How Does Vitamin D Boost The Immune System

How Does Vitamin D Boost The Immune System

Vitamin D is both a nutrient we eat and a hormone our bodies make. It is a fat-soluble vitamin that has long been known to help the body absorb and retain calcium and phosphorus; both are critical for building bone. Also, laboratory studies show that vitamin D can reduce cancer cell growth, help control infections and reduce inflammation. Many of the body's organs and tissues have receptors for vitamin D, which suggest important roles beyond bone health, and scientists are actively investigating other possible functions.

Few foods naturally contain vitamin D, though some foods are fortified with the vitamin. For most people, the best way to get enough vitamin D is taking a supplement because it is hard to eat enough through food. Vitamin D supplements are available in two forms: vitamin D2 ("ergocalciferol" or pre-vitamin D) and vitamin D3 ("cholecalciferol"). Both are also naturally occurring forms that are  produced in the presence of the sun's ultraviolet-B (UVB) rays, hence its nickname, "the sunshine vitamin," but D2 is produced in plants and fungi and D3 in animals, including humans. Vitamin D production in the skin is the primary natural source of vitamin D, but many people have insufficient levels because they live in places where sunlight is limited in winter, or because they have limited sun exposure due to being inside much of the time. Also, people with darker skin tend to have lower blood levels of vitamin D because the pigment (melanin) acts like a shade, reducing production of vitamin D (and also reducing damaging effects of sunlight on skin, including skin cancer).

Recommended Amounts

The Recommended Dietary Allowance for vitamin D provides the daily amount needed to maintain healthy bones and normal calcium metabolism in healthy people. It assumes minimal sun exposure.

RDA: The Recommended Dietary Allowance for adults 19 years and older is 600 IU daily for men and women, and for adults >70 years it is 800 IU daily.

UL: The Tolerable Upper Intake Level is the maximum daily intake unlikely to cause harmful effects on health. The UL for vitamin D for adults and children ages 9+ is 4,000 IU.

Many people may not be meeting the minimum requirement for the vitamin. NHANES data found that the median intake of vitamin D from food and supplements in women ages 51 to 71 years was 308 IU daily, but only 140 IU from food alone (including fortified products). [1] Worldwide, an estimated 1 billion people have inadequate levels of vitamin D in their blood, and deficiencies can be found in all ethnicities and age groups. [2-4]  In industrialized countries, doctors are seeing the resurgence of rickets, the bone-weakening disease that had been largely eradicated through vitamin D fortification. [5-7] There is scientific debate about how much vitamin D people need each day and what the optimal serum levels should be to prevent disease. The Institute of Medicine (IOM) released in November 2010 recommendations increasing the daily vitamin D intake for children and adults in the U.S. and Canada, to 600 IU per day. [1] The report also increased the upper limit from 2,000 to 4,000 IU per day. Although some groups such as The Endocrine Society recommend 1,500 to 2,000 IU daily to reach adequate serum levels of vitamin D, the IOM felt there was not enough evidence to establish a cause and effect link with vitamin D and health benefits other than for bone health.  Since that time,  new evidence has supported other benefits of consuming an adequate amount of vitamin D, although there is still not consensus on the amount considered to be adequate.

Vitamin D and Health

The role of vitamin D in disease prevention is a popular area of research, but clear answers about the benefit of taking amounts beyond the RDA are not conclusive. Although observational studies see a strong connection with lower rates of certain diseases in populations that live in sunnier climates or have higher serum levels of vitamin D, clinical trials that give people vitamin D supplements to affect a particular disease are still inconclusive. This may be due to different study designs, differences in the absorption rates of vitamin D in different populations, and different dosages given to participants. Learn more about the research on vitamin D and specific health conditions and diseases:

Bone health and muscle strength

Several studies link low vitamin D blood levels with an increased risk of fractures in older adults, and they suggest that vitamin D supplementation may prevent such fractures—as long as it is taken in a high enough dose. [8-12]

A meta-analysis of 12 randomized controlled trials that included more than 42,000 people 65+ years of age, most of them women, looked at vitamin D supplementation with or without calcium, and with calcium or a placebo. Researchers found that higher intakes of vitamin D supplements—about 500-800 IU per day—reduced hip and non-spine fractures by about 20%, while lower intakes (400 IU or less) failed to offer any fracture prevention benefit. [12]

A systematic review looked at the effect of vitamin D supplements taken with or without calcium on the prevention of hip fractures (primary outcome) and fractures of any type (secondary outcome) in older men and postmenopausal women 65+ years of age. It included 53 clinical trials with 91,791 participants who lived independently or in a nursing home or hospital. It did not find a strong association between vitamin D supplements alone and prevention of fractures of any type. However, it did find a small protective effect from all types of fractures when vitamin D was taken with calcium. All of the trials used vitamin D supplements containing 800 IU or less. [13]

Vitamin D may also help increase muscle strength, which in turn helps to prevent falls, a common problem that leads to substantial disability and death in older people. [14–16] A combined analysis of multiple studies found that taking 700 to 1,000 IU of vitamin D per day lowered the risk of falls by 19%, but taking 200 to 600 IU per day did not offer any such protection. [17]

Though taking 800-1,000 IU daily may have benefit for bone health in older adults, it is important to be cautious of very high dosage supplements. A clinical trial that gave women 70+ years of age a once-yearly dosage of vitamin D at 500,000 IU for five years caused a 15% increased risk of falls and a 26% higher fracture risk than women who received a placebo. [18] It was speculated that super-saturating the body with a very high dose given infrequently may have actually promoted lower blood levels of the active form of vitamin D that might not have occurred with smaller, more frequent doses. [13]

Cancer

Nearly 30 years ago, researchers noticed an intriguing relationship between colon cancer deaths and geographic location: People who lived at higher latitudes, such as in the northern U.S., had higher rates of death from colon cancer than people who lived closer to the equator. [19] Many scientific hypotheses about vitamin D and disease stem from studies that have compared solar radiation and disease rates in different countries. These studies can be a good starting point for other research but don't provide the most definitive information. The sun's UVB rays are weaker at higher latitudes, and in turn, people's vitamin D blood levels in these locales tend to be lower. This led to the hypothesis that low vitamin D levels might somehow increase colon cancer risk. [3]

Animal and laboratory studies have found that vitamin D can inhibit the development of tumors and slow the growth of existing tumors including those from the breast, ovary, colon, prostate, and brain. In humans, epidemiological studies show that higher serum levels of vitamin D are associated with substantially lower rates of colon, pancreatic, prostate, and other cancers, with the evidence strongest for colorectal cancer. [20-32]

However, clinical trials have not found a consistent association:

The Women's Health Initiative trial, which followed roughly 36,000 women for an average of seven years, failed to find any reduction in colon or breast cancer risk in women who received daily supplements of 400 IU of vitamin D and 1,000 mg of calcium, compared with those who received a placebo. [33,34] Limitations of the study were suggested: 1) the relatively low dose of vitamin D given, 2) some people in the placebo group decided on their own to take extra calcium and vitamin D supplements, minimizing the differences between the placebo group and the supplement group, and 3) about one-third of the women assigned to vitamin D did not take their supplements. 4) seven years may be too short to expect a reduction in cancer risk. [35,36]

A large clinical trial called the VITamin D and OmegA-3 TriaL (VITAL) followed 25,871 men and women 50+ years of age free of any cancers at the start of the study who took either a 2,000 IU vitamin D supplement or placebo daily for a median of five years. [37] The findings did not show significantly different rates of breast, prostate, and colorectal cancer between the vitamin D and placebo groups. The authors noted that a longer follow-up period would be necessary to better assess potential effects of supplementation, as many cancers take at least 5-10 years to develop.

Although vitamin D does not seem to be a major factor in reducing cancer incidence, evidence including that from randomized trials suggests that having higher vitamin D status may improve survival if one develops cancer.  In the VITAL trial, a lower death rate from cancer was observed in those assigned to take vitamin D, and this benefit seemed to increase over time since starting on vitamin D. A meta-analysis of randomized trials of vitamin D, which included the VITAL study, found a 13% statistically significant lower risk of cancer mortality in those assigned to vitamin D compared to placebo. [38] These findings are consistent with observational data, which suggest that vitamin D may have a stronger effect on cancer progression than for incidence.

Heart disease

The heart is basically a large muscle, and like skeletal muscle, it has receptors for vitamin D. [39] Immune and inflammatory cells that play a role in cardiovascular disease conditions like atherosclerosis are regulated by vitamin D. [40] The vitamin also helps to keep arteries flexible and relaxed, which in turn helps to control high blood pressure. [41]

In the Health Professionals Follow-up Study nearly 50,000 healthy men were followed for 10 years. [42] Those who had the lowest levels of vitamin D were twice as likely to have a heart attack as men who had the highest levels. Meta-analyses of epidemiological studies have found that people with the lowest serum levels of vitamin D had a significantly increased risk of strokes and any heart disease event compared with those with the highest levels. [40;43-46]

However, taking vitamin D supplements has not been found to reduce cardiovascular risk. A meta-analysis of 51 clinical trials did not demonstrate that vitamin D supplementation lowered the risk of heart attack, stroke, or deaths from cardiovascular disease. [47] The VITamin D and OmegA-3 TriaL (VITAL) came to the same conclusion; it followed 25,871 men and women free of cardiovascular disease who took either a 2,000 IU vitamin D supplement or placebo daily for a median of five years. No association was found between taking the supplements and a lower risk of major cardiovascular events (heart attack, stroke, or death from cardiovascular causes) compared with the placebo. [37]

Type 2 diabetes

Vitamin D deficiency may negatively affect the biochemical pathways that lead to the development of Type 2 diabetes (T2DM), including impairment of beta cell function in the pancreas, insulin resistance, and inflammation. Prospective observational studies have shown that higher vitamin D blood levels are associated with lower rates of T2DM. [48]

More than 83,000 women without diabetes at baseline were followed in the Nurses' Health Study for the development of T2DM. Vitamin D and calcium intakes from diet and supplements were assessed throughout the 20-year study. [49] The authors found that when comparing the women with the highest intakes of vitamin D from supplements with women with the lowest intakes, there was a 13% lower risk of developing T2DM. The effect was even stronger when vitamin D was combined with calcium: there was a 33% lower risk of T2DM in women when comparing the highest intakes of calcium and vitamin D from supplements (>1,200 mg, >800 IU daily) with the lowest intakes (<600 mg, 400 IU).

A randomized clinical trial gave 2,423 adults who had prediabetes either 4000 IU of vitamin D or a placebo daily for two years. The majority of participants did not have vitamin D deficiency at the start of the study. At two years, vitamin D blood levels in the supplement versus placebo group was 54.3 ng/mL versus 28.2 ng/mL, respectively, but no significant differences were observed in rates of T2DM at the 2.5 year follow-up. [50] The authors noted that a lack of effect of vitamin D may have been due to the majority of participants having vitamin D blood levels in a normal range of greater than 20 ng/mL, which is considered an acceptable level to reduce health risks.  Notably, among the participants who had the lowest blood levels of vitamin D at the beginning of the study, vitamin D supplementation did reduce risk of diabetes. This is consistent with the important concept that taking additional vitamin D may not benefit those who already have adequate blood levels, but those with initially low blood levels may benefit.

Immune function

Vitamin D's role in regulating the immune system has led scientists to explore two parallel research paths: Does vitamin D deficiency contribute to the development of multiple sclerosis, type 1 diabetes, and other so-called "autoimmune" diseases, where the body's immune system attacks its own organs and tissues? And could vitamin D supplements help boost our body's defenses to fight infectious disease, such as tuberculosis and seasonal flu?

Multiple Sclerosis
The rate of multiple sclerosis (MS) is increasing in both developed and developing countries, with an unclear cause. However, a person's genetic background plus environmental factors including inadequate vitamin D and UVB exposure have been identified to increase risk. [51] Vitamin D was first proposed over 40 years ago as having a role in MS given observations at the time including that rates of MS were much higher far north (or far south) of the equator than in sunnier climates, and that geographic regions with diets high in fish had lower rates of MS. [52] A prospective study of dietary intake of vitamin D found women with daily intake above 400 IU had a 40% lower risk of MS. [53] In a study among healthy young adults in the US, white men and women with the highest vitamin D serum levels had a 62% lower risk of developing MS than those with the lowest vitamin D levels. [54] The study didn't find this effect among black men and women, possibly because there were fewer black study participants and most of them had low vitamin D levels, making it harder to find any link between vitamin D and MS if one exists. Another prospective study in young adults from Sweden also found a 61% lower risk of MS with higher serum vitamin D levels; [55] and a prospective study among young Finnish women found that low serum vitamin D levels were associated with a 43% increased risk of MS. [56] In prospective studies of persons with MS, higher vitamin D levels have been associated with reduced disease activity and progression. [57,58] While several clinical trials are underway to examine vitamin D as a treatment in persons with MS, there are no clinical trials aimed at prevention of MS, likely because MS is a rare disease and the trial would need to be large and of long duration. Collectively, the current evidence suggests that low vitamin D may have a causal role in MS and if so, approximately 40% of cases may be prevented by correcting vitamin D insufficiency. [59] This conclusion has been strengthened substantially by recent evidence that genetically determined low levels of vitamin D predict higher risk of multiple sclerosis.

Type 1 Diabetes
Type 1 diabetes (T1D) is another disease that varies with geography—a child in Finland is about 400 times more likely to develop T1D than a child in Venezuela. [60] While this may largely be due to genetic differences, some studies suggest that T1D rates are lower in sunnier areas. Early evidence suggesting that vitamin D may play a role in T1D comes from a 30-year study that followed more than 10,000 Finnish children from birth: Children who regularly received vitamin D supplements during infancy had a nearly 90% lower risk of developing type 1 diabetes than those who did not receive supplements. [61] However, multiple studies examining the association between dietary vitamin D or trials supplementing children at high risk for T1D with vitamin D have produced mixed and inconclusive results [62] Approximately 40% of T1D cases begin in adulthood. A prospective study among healthy young adults in the US found that white individuals with the highest levels of serum vitamin D had a 44% lower risk of developing T1D in adulthood than those with the lowest levels. [63] No randomized controlled trials on vitamin D and adult onset T1D have been conducted, and it is not clear that they would be possible to conduct. More research is needed in this area.

Flu and the Common Cold
The flu virus wreaks the most havoc in the winter, abating in the summer months. This seasonality led a British doctor to hypothesize that a sunlight-related "seasonal stimulus" triggered influenza outbreaks. [64] More than 20 years after this initial hypothesis, several scientists published a paper suggesting that vitamin D may be the seasonal stimulus. [65] Among the evidence they cite:

• • Vitamin D levels are lowest in the winter months. [65]
  • The active form of vitamin D tempers the damaging inflammatory response of some white blood cells, while it also boosts immune cells' production of microbe-fighting proteins. [65]
  • Children who have vitamin D-deficiency rickets are more likely to get respiratory infections, while children exposed to sunlight seem to have fewer respiratory infections. [65]
  • Adults who have low vitamin D levels are more likely to report having had a recent cough, cold, or upper respiratory tract infection. [66]

A randomized controlled trial in Japanese school children tested whether taking daily vitamin D supplements would prevent seasonal flu. [67] The trial followed nearly 340 children for four months during the height of the winter flu season. Half of the study participants received pills that contained 1,200 IU of vitamin D; the other half received placebo pills. Researchers found that type A influenza rates in the vitamin D group were about 40% lower than in the placebo group; there was no significant difference in type B influenza rates.

Although randomized controlled trials exploring the potential of vitamin D to prevent other acute respiratory infections have yielded mixed results, a large meta-analysis of individual participant data indicated that daily or weekly vitamin D supplementation lowers risk of acute respiratory infections. [68] This effect was particularly prominent for very deficient individuals.

The findings from this large meta-analysis have raised the possibility that low vitamin D levels may also increase risk of or severity of novel coronavirus 2019 (COVID-19) infection. Although there is no direct evidence on this issue because this such a new disease, avoiding low levels of vitamin D makes sense for this and other reasons. Thus, if there is reason to believe that levels might be low, such as having darker skin or limited sun exposure, taking a supplement of 1000 or 2000 IU per day is reasonable. This amount is now part of many standard multiple vitamin supplements and inexpensive.

More research is needed before we can definitively say that vitamin D protects against the flu and other acute respiratory infections. Even if vitamin D has some benefit, don't skip your flu shot. And when it comes to limiting risk of COVID-19, it is important to practice careful social distancing and hand washing.

Tuberculosis
Before the advent of antibiotics, sunlight and sun lamps were part of the standard treatment for tuberculosis (TB). [69] More recent research suggests that the "sunshine vitamin" may be linked to TB risk. Several case-control studies, when analyzed together, suggest that people diagnosed with tuberculosis have lower vitamin D levels than healthy people of similar age and other characteristics. [70] Such studies do not follow individuals over time, so they cannot tell us whether vitamin D deficiency led to the increased TB risk or whether taking vitamin D supplements would prevent TB. There are also genetic differences in the receptor that binds vitamin D, and these differences may influence TB risk. [71] Again, more research is needed.

Risk of premature death

A promising report in the Archives of Internal Medicine suggests that taking vitamin D supplements may reduce overall mortality rates: A combined analysis of multiple studies found that taking modest levels of vitamin D supplements was associated with a statistically significant 7% reduction in mortality from any cause. [72] The analysis looked at the findings from 18 randomized controlled trials that enrolled a total of nearly 60,000 study participants; most of the study participants took between 400 and 800 IU of vitamin D per day for an average of five years. Keep in mind that this analysis has several limitations, chief among them the fact that the studies it included were not designed to explore mortality in general, or explore specific causes of death.  A recent meta-analysis suggests that this reduction in mortality is driven mostly by a reduction in cancer mortality. [38] More research is needed before any broad claims can be made about vitamin D and mortality. [73]

Food Sources

Few foods are naturally rich in vitamin D3. The best sources are the flesh of fatty fish and fish liver oils. Smaller amounts are found in egg yolks, cheese, and beef liver. Certain mushrooms contain some vitamin D2; in addition some commercially sold mushrooms contain higher amounts of D2 due to intentionally being exposed to high amounts of ultraviolet light. Many foods and supplements are fortified with vitamin D like dairy products and cereals.

• Cod liver oil
• Salmon
• Swordfish
• Tuna fish
• Orange juice fortified with vitamin D
• Dairy and plant milks fortified with vitamin D
• Sardines
• Beef liver
• Egg yolk
• Fortified cereals

Is There a Difference Between Vitamin D3 and Vitamin D2 Supplements?

If you purchase vitamin D supplements, you may see two different forms: vitamin D2 and vitamin D3. Vitamin D2 is made from plants and is found in fortified foods and some supplements. Vitamin D3 is naturally produced in the human body and is found in animal foods. There is ongoing debate whether vitamin D3 "cholecalciferol" is better than vitamin D2 "ergocalciferol" at increasing blood levels of the vitamin. A meta-analysis of randomized controlled trials that compared the effects of vitamin D2 and D3 supplements on blood levels found that D3 supplements tended to raise blood concentrations of the vitamin more and sustained those levels longer than D2. [74,75] Some experts cite vitamin D3 as the preferred form as it is naturally produced in the body and found in most foods that naturally contain the vitamin.

Ultraviolet Light

Vitamin D3 can be formed when a chemical reaction occurs in human skin, when a steroid called 7-dehydrocholesterol is broken down by the sun's UVB light or so-called "tanning" rays. The amount of the vitamin absorbed can vary widely. The following are conditions that decrease exposure to UVB light and therefore lessen vitamin D absorption:

• Use of sunscreen; correctly applied sunscreen can reduce vitamin D absorption by more than 90%. [76]
• Wearing full clothing that covers the skin.
• Spending limited time outdoors.
• Darker skin tones due to having higher amounts of the pigment melanin, which acts as a type of natural sunscreen. [77]
• Older ages when there is a decrease in 7-dehydrocholesterol levels and changes in skin, and a population that is likely to spend more time indoors.
• Certain seasons and living in northern latitudes above the equator where UVB light is weaker. [76] In the northern hemisphere, people who live in Boston (U.S.), Edmonton (Canada), and Bergen (Norway) can't make enough vitamin D from the sun for 4, 5, and 6 months out of the year, respectively. [76] In the southern hemisphere, residents of Buenos Aires (Argentina) and Cape Town (South Africa) make far less vitamin D from the sun during their winter months (June through August) than they can during their spring and summer months. [76] The body stores vitamin D from summer sun exposure, but it must last for many months. By late winter, many people in these higher-latitude locales are deficient. [77]

Note that because ultraviolet rays can cause skin cancer, it is important to avoid excessive sun exposure and in general, tanning beds should not be used.

Signs of Deficiency and Toxicity

Deficiency

Vitamin D deficiency may occur from a lack in the diet, poor absorption, or having a metabolic need for higher amounts. If one is not eating enough vitamin D and does not receive enough ultraviolet sun exposure over an extended period (see section above), a deficiency may arise. People who cannot tolerate or do not eat milk, eggs, and fish, such as those with a lactose intolerance or who follow a vegan diet, are at higher risk for a deficiency. Other people at high risk of vitamin D deficiency include:

• People with inflammatory bowel disease (ulcerative colitis, Crohn's disease) or other conditions that disrupt the normal digestion of fat. Vitamin D is a fat-soluble vitamin that depends on the gut's ability to absorb dietary fat.
• People who are obese tend to have lower blood vitamin D levels. Vitamin D accumulates in excess fat tissues but is not easily available for use by the body when needed. Higher doses of vitamin D supplementation may be needed to achieve a desirable blood level. Conversely, blood levels of vitamin D rise when obese people lose weight.
• People who have undergone gastric bypass surgery, which typically removes the upper part of the small intestine where vitamin D is absorbed.

Conditions resulting from prolonged vitamin D deficiency:

• Rickets: A condition in infants and children of soft bones and skeletal deformities caused by failure of bone tissue to harden.
• Osteomalacia: A condition in adults of weak and softened bones that can be reversed with supplementation. This is different than osteoporosis, in which the bones are porous and brittle and the condition is irreversible.

Toxicity

Vitamin D toxicity most often occurs from taking supplements. The low amounts of the vitamin found in food are unlikely to reach a toxic level, and a high amount of sun exposure does not lead to toxicity because excess heat on the skin prevents D3 from forming. It is advised to not take daily vitamin D supplements containing more than 4,000 IU unless monitored under the supervision of your doctor.

Symptoms of toxicity:

• Anorexia
• Weight loss
• Irregular heart beat
• Hardening of blood vessels and tissues due to increased blood levels of calcium, potentially leading to damage of the heart and kidneys

Did You Know?

• Catching the sun's rays in a sunny office or driving in a car unfortunately won't help to obtain vitamin D as window glass completely blocks UVB ultraviolet light.

References

1. Institute of Medicine. Dietary Reference Intakes for Calcium and Vitamin D. Washington, D.C.: National Academies Press, 2010. https://www.ncbi.nlm.nih.gov/books/NBK56070/
2. Holick MF. Vitamin D deficiency. New England Journal of Medicine. 2007 Jul 19;357(3):266-81.
3. Gordon CM, DePeter KC, Feldman HA, Grace E, Emans SJ. Prevalence of vitamin D deficiency among healthy adolescents. Archives of pediatrics & adolescent medicine. 2004 Jun 1;158(6):531-7.
4. Lips PT. Worldwide status of vitamin D nutrition. The Journal of steroid biochemistry and molecular biology. 2010 Jul 1;121(1-2):297-300.
5. Robinson PD, Högler W, Craig ME, Verge CF, Walker JL, Piper AC, Woodhead HJ, Cowell CT, Ambler GR. The re-emerging burden of rickets: a decade of experience from Sydney. Archives of Disease in Childhood. 2006 Jul 1;91(7):564-8.
6. Kreiter SR, Schwartz RP, Kirkman Jr HN, Charlton PA, Calikoglu AS, Davenport ML. Nutritional rickets in African American breast-fed infants. The Journal of pediatrics. 2000 Aug 1;137(2):153-7.
7. Misra M, Pacaud D, Petryk A, Collett-Solberg PF, Kappy M. Vitamin D deficiency in children and its management: review of current knowledge and recommendations. Pediatrics. 2008 Aug 1;122(2):398-417.
8. Boonen S, Lips P, Bouillon R, Bischoff-Ferrari HA, Vanderschueren D, Haentjens P. Need for additional calcium to reduce the risk of hip fracture with vitamin D supplementation: evidence from a comparative metaanalysis of randomized controlled trials. The Journal of Clinical Endocrinology & Metabolism. 2007 Apr 1;92(4):1415-23.
9. Bischoff-Ferrari HA, Willett WC, Wong JB, Giovannucci E, Dietrich T, Dawson-Hughes B. Fracture prevention with vitamin D supplementation: a meta-analysis of randomized controlled trials. Jama. 2005 May 11;293(18):2257-64.
10. Cauley JA, LaCroix AZ, Wu L, Horwitz M, Danielson ME, Bauer DC, Lee JS, Jackson RD, Robbins JA, Wu C, Stanczyk FZ. Serum 25-hydroxyvitamin D concentrations and risk for hip fractures. Annals of internal medicine. 2008 Aug 19;149(4):242-50.
11. Cauley JA, Parimi N, Ensrud KE, Bauer DC, Cawthon PM, Cummings SR, Hoffman AR, Shikany JM, Barrett‐Connor E, Orwoll E. Serum 25‐hydroxyvitamin D and the risk of hip and nonspine fractures in older men. Journal of Bone and Mineral Research. 2010 Mar;25(3):545-53.
12. Bischoff-Ferrari HA, Willett WC, Wong JB, Stuck AE, Staehelin HB, Orav EJ, Thoma A, Kiel DP, Henschkowski J. Prevention of nonvertebral fractures with oral vitamin D and dose dependency: a meta-analysis of randomized controlled trials. Archives of internal medicine. 2009 Mar 23;169(6):551-61.
13. Avenell A, Mak JC, O'Connell D. Vitamin D and vitamin D analogues for preventing fractures in post‐menopausal women and older men. Cochrane Database of Systematic Reviews. 2014(4).
14. Bischoff-Ferrari HA, Dawson-Hughes B, Willett WC, Staehelin HB, Bazemore MG, Zee RY, Wong JB. Effect of vitamin D on falls: a meta-analysis. Jama. 2004 Apr 28;291(16):1999-2006.
15. Broe KE, Chen TC, Weinberg J, Bischoff‐Ferrari HA, Holick MF, Kiel DP. A higher dose of vitamin D reduces the risk of falls in nursing home residents: a randomized, multiple‐dose study. Journal of the American Geriatrics Society. 2007 Feb;55(2):234-9.
16. Bischoff-Ferrari HA, Orav EJ, Dawson-Hughes B. Effect of cholecalciferol plus calcium on falling in ambulatory older men and women: a 3-year randomized controlled trial. Archives of internal medicine. 2006 Feb 27;166(4):424-30.
17. Bischoff-Ferrari HA, Dawson-Hughes B, Staehelin HB, Orav JE, Stuck AE, Theiler R, Wong JB, Egli A, Kiel DP, Henschkowski J. Fall prevention with supplemental and active forms of vitamin D: a meta-analysis of randomised controlled trials. BMJ. 2009 Oct 1;339:b3692.
18. Sanders KM, Stuart AL, Williamson EJ, Simpson JA, Kotowicz MA, Young D, Nicholson GC. Annual high-dose oral vitamin D and falls and fractures in older women: a randomized controlled trial. Jama. 2010 May 12;303(18):1815-22.
19. Garland CF, Garland FC. Do sunlight and vitamin D reduce the likelihood of colon cancer?. International journal of epidemiology. 1980 Sep 1;9(3):227-31.
20. Garland CF, Gorham ED, Mohr SB, Garland FC. Vitamin D for cancer prevention: global perspective. Annals of epidemiology. 2009 Jul 1;19(7):468-83.
21. McCullough ML, Zoltick ES, Weinstein SJ, Fedirko V, Wang M, Cook NR, Eliassen AH, Zeleniuch-Jacquotte A, Agnoli C, Albanes D, Barnett MJ. Circulating vitamin D and colorectal cancer risk: an international pooling project of 17 cohorts. JNCI: Journal of the National Cancer Institute. 2019 Feb 1;111(2):158-69.
22. Yin L, Grandi N, Raum E, Haug U, Arndt V, Brenner H. Meta‐analysis: longitudinal studies of serum vitamin D and colorectal cancer risk. Alimentary pharmacology & therapeutics. 2009 Jul;30(2):113-25.
23. Wu K, Feskanich D, Fuchs CS, Willett WC, Hollis BW, Giovannucci EL. A nested case–control study of plasma 25-hydroxyvitamin D concentrations and risk of colorectal cancer. Journal of the National Cancer Institute. 2007 Jul 18;99(14):1120-9.
24. Gorham ED, Garland CF, Garland FC, Grant WB, Mohr SB, Lipkin M, Newmark HL, Giovannucci E, Wei M, Holick MF. Optimal vitamin D status for colorectal cancer prevention: a quantitative meta analysis. American journal of preventive medicine. 2007 Mar 1;32(3):210-6.
25. Giovannucci E. Epidemiological evidence for vitamin D and colorectal cancer. Journal of Bone and Mineral Research. 2007 Dec;22(S2):V81-5.
26. Lin J, Zhang SM, Cook NR, Manson JE, Lee IM, Buring JE. Intakes of calcium and vitamin D and risk of colorectal cancer in women. American journal of epidemiology. 2005 Apr 15;161(8):755-64.
27. Huncharek M, Muscat J, Kupelnick B. Colorectal cancer risk and dietary intake of calcium, vitamin D, and dairy products: a meta-analysis of 26,335 cases from 60 observational studies. Nutrition and cancer. 2008 Dec 31;61(1):47-69.
28. Bertone-Johnson ER, Chen WY, Holick MF, Hollis BW, Colditz GA, Willett WC, Hankinson SE. Plasma 25-hydroxyvitamin D and 1, 25-dihydroxyvitamin D and risk of breast cancer. Cancer Epidemiology and Prevention Biomarkers. 2005 Aug 1;14(8):1991-7.
29. Garland CF, Gorham ED, Mohr SB, Grant WB, Giovannucci EL, Lipkin M, Newmark H, Holick MF, Garland FC. Vitamin D and prevention of breast cancer: pooled analysis. The Journal of steroid biochemistry and molecular biology. 2007 Mar 1;103(3-5):708-11.
30. Lin J, Manson JE, Lee IM, Cook NR, Buring JE, Zhang SM. Intakes of calcium and vitamin D and breast cancer risk in women. Archives of Internal Medicine. 2007 May 28;167(10):1050-9.
31. Robien K, Cutler GJ, Lazovich D. Vitamin D intake and breast cancer risk in postmenopausal women: the Iowa Women's Health Study. Cancer causes & control. 2007 Sep 1;18(7):775-82.
32. Freedman DM, Chang SC, Falk RT, Purdue MP, Huang WY, McCarty CA, Hollis BW, Graubard BI, Berg CD, Ziegler RG. Serum levels of vitamin D metabolites and breast cancer risk in the prostate, lung, colorectal, and ovarian cancer screening trial. Cancer Epidemiology and Prevention Biomarkers. 2008 Apr 1;17(4):889-94.
33. Wactawski-Wende J, Kotchen JM, Anderson GL, Assaf AR, Brunner RL, O'sullivan MJ, Margolis KL, Ockene JK, Phillips L, Pottern L, Prentice RL. Calcium plus vitamin D supplementation and the risk of colorectal cancer. New England Journal of Medicine. 2006 Feb 16;354(7):684-96.
34. Chlebowski RT, Johnson KC, Kooperberg C, Pettinger M, Wactawski-Wende J, Rohan T, Rossouw J, Lane D, O'Sullivan MJ, Yasmeen S, Hiatt RA. Calcium plus vitamin D supplementation and the risk of breast cancer. JNCI: Journal of the National Cancer Institute. 2008 Nov 19;100(22):1581-91.
35. Holick MF. Calcium plus vitamin D and the risk of colorectal cancer. N Engl J Med. 2006; 354:2287-8; author reply 2287-8.
36. Giovannucci E. Calcium plus vitamin D and the risk of colorectal cancer. N Engl J Med. 2006; 354:2287-8; author reply 2287-8.
37. Manson JE, Cook NR, Lee IM, Christen W, Bassuk SS, Mora S, Gibson H, Gordon D, Copeland T, D'Agostino D, Friedenberg G. Vitamin D supplements and prevention of cancer and cardiovascular disease. New England Journal of Medicine. 2019 Jan 3;380(1):33-44.
38. Keum N, Lee DH, Greenwood DC, Manson JE, Giovannucci E. Vitamin D supplementation and total cancer incidence and mortality: a meta-analysis of randomized controlled trials. Annals of Oncology. 2019 May 1;30(5):733-43.
39. Giovannucci E. Expanding roles of vitamin D. J Clin Endocrinol Metab. 2009; 94:418-20.
40. Norman PE, Powell JT. Vitamin D and cardiovascular disease. Circulation research. 2014 Jan 17;114(2):379-93.
41. Holick MF. The vitamin D deficiency pandemic and consequences for nonskeletal health: mechanisms of action. Molecular aspects of medicine. 2008 Dec 1;29(6):361-8.
42. Giovannucci E, Liu Y, Hollis BW, Rimm EB. 25-hydroxyvitamin D and risk of myocardial infarction in men: a prospective study. Archives of internal medicine. 2008 Jun 9;168(11):1174-80.
43. Pilz S, März W, Wellnitz B, Seelhorst U, Fahrleitner-Pammer A, Dimai HP, Boehm BO, Dobnig H. Association of vitamin D deficiency with heart failure and sudden cardiac death in a large cross-sectional study of patients referred for coronary angiography. The Journal of Clinical Endocrinology & Metabolism. 2008 Oct 1;93(10):3927-35.
44. Pilz S, Dobnig H, Fischer JE, Wellnitz B, Seelhorst U, Boehm BO, März W. Low vitamin D levels predict stroke in patients referred to coronary angiography. Stroke. 2008 Sep 1;39(9):2611-3.
45. Booth TW, Lanier PJ. Vitamin D deficiency and risk of cardiovascular disease. Circulation Res117. 2008;503:511.
46. Dobnig H, Pilz S, Scharnagl H, Renner W, Seelhorst U, Wellnitz B, Kinkeldei J, Boehm BO, Weihrauch G, Maerz W. Independent association of low serum 25-hydroxyvitamin D and 1, 25-dihydroxyvitamin D levels with all-cause and cardiovascular mortality. Archives of internal medicine. 2008 Jun 23;168(12):1340-9.
47. Elamin MB, Abu Elnour NO, Elamin KB, Fatourechi MM, Alkatib AA, Almandoz JP, Liu H, Lane MA, Mullan RJ, Hazem A, Erwin PJ. Vitamin D and cardiovascular outcomes: a systematic review and meta-analysis. The Journal of Clinical Endocrinology & Metabolism. 2011 Jul 1;96(7):1931-42.
48. Mitri J, Pittas AG. Vitamin D and diabetes. Endocrinol Metab Clin North Am. 2014 Mar;43(1):205-32.
49. Pittas AG, Dawson-Hughes B, Li T, Van Dam RM, Willett WC, Manson JE, Hu FB. Vitamin D and calcium intake in relation to type 2 diabetes in women. Diabetes care. 2006 Mar 1;29(3):650-6.
50. Pittas AG, Dawson-Hughes B, Sheehan P, Ware JH, Knowler WC, Aroda VR, Brodsky I, Ceglia L, Chadha C, Chatterjee R, Desouza C, Dolor R, Foreyt J, Fuss P, Ghazi A, Hsia DS, Johnson KC, Kashyap SR, Kim S, LeBlanc ES, Lewis MR, Liao E, Neff LM, Nelson J, O'Neil P, Park J, Peters A, Phillips LS, Pratley R, Raskin P, Rasouli N, Robbins D, Rosen C, Vickery EM, Staten M; D2d Research Group. Vitamin D Supplementation and Prevention of Type 2 Diabetes. N Engl J Med. 2019 Aug 8;381(6):520-530
51. Dobson R, Giovannoni G. Multiple sclerosis–a review. European journal of neurology. 2019 Jan;26(1):27-40.
52. Goldberg P. Multiple sclerosis: vitamin D and calcium as environmental determinants of prevalence: (A viewpoint) part 1: sunlight, dietary factors and epidemiology. International Journal of Environmental Studies. 1974 Jan 1;6(1):19-27.
53. Munger KL, Zhang SM, O'reilly E, Hernan MA, Olek MJ, Willett WC, Ascherio A. Vitamin D intake and incidence of multiple sclerosis. Neurology. 2004 Jan 13;62(1):60-5.
54. Munger KL, Levin LI, Hollis BW, Howard NS, Ascherio A. Serum 25-hydroxyvitamin D levels and risk of multiple sclerosis. Jama. 2006 Dec 20;296(23):2832-8.
55. Salzer J, Hallmans G, Nyström M, Stenlund H, Wadell G, Sundström P. Vitamin D as a protective factor in multiple sclerosis. Neurology. 2012 Nov 20;79(21):2140-5.
56. Munger KL, Hongell K, Åivo J, Soilu-Hänninen M, Surcel HM, Ascherio A. 25-Hydroxyvitamin D deficiency and risk of MS among women in the Finnish Maternity Cohort. Neurology. 2017 Oct 10;89(15):1578-83.
57. Ascherio A, Munger KL, White R, Köchert K, Simon KC, Polman CH, Freedman MS, Hartung HP, Miller DH, Montalbán X, Edan G. Vitamin D as an early predictor of multiple sclerosis activity and progression. JAMA neurology. 2014 Mar 1;71(3):306-14.
58. Fitzgerald KC, Munger KL, Köchert K, Arnason BG, Comi G, Cook S, Goodin DS, Filippi M, Hartung HP, Jeffery DR, O'Connor P. Association of vitamin D levels with multiple sclerosis activity and progression in patients receiving interferon beta-1b. JAMA neurology. 2015 Dec 1;72(12):1458-65.
59. Ascherio A, Munger KL. Epidemiology of multiple sclerosis: from risk factors to prevention—an update. InSeminars in neurology 2016 Apr (Vol. 36, No. 02, pp. 103-114). Thieme Medical Publishers.
60. Gillespie KM. Type 1 diabetes: pathogenesis and prevention. Cmaj. 2006 Jul 18;175(2):165-70.
61. Hyppönen E, Läärä E, Reunanen A, Järvelin MR, Virtanen SM. Intake of vitamin D and risk of type 1 diabetes: a birth-cohort study. The Lancet. 2001 Nov 3;358(9292):1500-3.
62. Rewers M, Ludvigsson J. Environmental risk factors for type 1 diabetes. The Lancet. 2016 Jun 4;387(10035):2340-8.
63. Munger KL, Levin LI, Massa J, Horst R, Orban T, Ascherio A. Preclinical serum 25-hydroxyvitamin D levels and risk of type 1 diabetes in a cohort of US military personnel. American journal of epidemiology. 2013 Mar 1;177(5):411-9.
64. Hope-Simpson RE. The role of season in the epidemiology of influenza. Epidemiology & Infection. 1981 Feb;86(1):35-47.
65. Cannell JJ, Vieth R, Umhau JC, Holick MF, Grant WB, Madronich S, Garland CF, Giovannucci E. Epidemic influenza and vitamin D. Epidemiology & Infection. 2006 Dec;134(6):1129-40.
66. Ginde AA, Mansbach JM, Camargo CA. Association between serum 25-hydroxyvitamin D level and upper respiratory tract infection in the Third National Health and Nutrition Examination Survey. Archives of internal medicine. 2009 Feb 23;169(4):384-90.
67. Urashima M, Segawa T, Okazaki M, Kurihara M, Wada Y, Ida H. Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. The American journal of clinical nutrition. 2010 May 1;91(5):1255-60.
68. Martineau AR, Jolliffe DA, Hooper RL, Greenberg L, Aloia JF, Bergman P, Dubnov-Raz G, Esposito S, Ganmaa D, Ginde AA, Goodall EC. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ. 2017 Feb 15;356:i6583.
69. Zasloff M. Fighting infections with vitamin D. Nature medicine. 2006 Apr;12(4):388-90.
70. Nnoaham KE, Clarke A. Low serum vitamin D levels and tuberculosis: a systematic review and meta-analysis. International journal of epidemiology. 2008 Feb 1;37(1):113-9.
71. Chocano-Bedoya P, Ronnenberg AG. Vitamin D and tuberculosis. Nutrition reviews. 2009 May 1;67(5):289-93.
72. Autier P, Gandini S. Vitamin D supplementation and total mortality: a meta-analysis of randomized controlled trials. Archives of internal medicine. 2007 Sep 10;167(16):1730-7.
73. Giovannucci E. Can vitamin D reduce total mortality?. Archives of Internal Medicine. 2007 Sep 10;167(16):1709-10.
74. Tripkovic L, Lambert H, Hart K, Smith CP, Bucca G, Penson S, Chope G, Hyppönen E, Berry J, Vieth R, Lanham-New S. Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis. The American journal of clinical nutrition. 2012 Jun 1;95(6):1357-64.
75. Wilson LR, Tripkovic L, Hart KH, Lanham-New SA. Vitamin D deficiency as a public health issue: using vitamin D 2 or vitamin D 3 in future fortification strategies. Proceedings of the Nutrition Society. 2017 Aug;76(3):392-9.
76. Holick MF. Vitamin D: importance in the prevention of cancers, type 1 diabetes, heart disease, and osteoporosis.Am J Clin Nutr. 2004; 79:362-71
77. Holick MF. Vitamin D deficiency.N Engl J Med. 2007; 357:266-81.

Updated March 2020

Terms of Use

The contents of this website are for educational purposes and are not intended to offer personal medical advice. You should seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. The Nutrition Source does not recommend or endorse any products.

How Does Vitamin D Boost The Immune System

Source: https://www.hsph.harvard.edu/nutritionsource/vitamin-d/

Share:

Read More

Century Vitamin D

Century Vitamin D

21st Century, Vitamin D3, 25 mcg (1,000 IU), 300 Tablets

In Stock

Package Quantity: 300 Count

• Expiration Date: November 1 2023
• Date First Available: May 9 2012
• Shipping Weight:
• Product code: CEN-27292
• UPC Code: 740985272923
• Package Quantity: 300 Count
• Dimensions:

Similar item to consider

Gummiology, Adult Gummies, Vitamin D3 Gummies, No Gelatin, Peach & Sour Cherry Flavors, 100 Vegetarian Gummies

$9.00

Frequently purchased together

Product overview

Description

• Vitamin Supplement
• Strong Bones & Immune Support
• Gluten Free
• Guaranteed Quality - Laboratory Tested

Vitamin D3 is essential for absorption of calcium and supports bone, teeth and immune system health.

Suggested use

As a vitamin supplement, adults take one (1) tablet daily with any meal or as directed by your healthcare provider. Do not exceed recommended dosage. Individual results may vary.

Other ingredients

Cellulose, croscarmellose sodium, maltodextrin, stearic acid. Contains <2% of: Magnesium stearate, silicon dioxide.

No added yeast, artificial flavors or colors.

Warnings

Consult a healthcare provider prior to use if pregnant, nursing, on medications, have a medical condition or are planning a medical procedure. Stop use and contact a physician if adverse reactions occur.

Keep out of reach of children. Do not use if product appears to be tampered with or seal is broken. Store at room temperature.

Disclaimer

While iHerb strives to ensure the accuracy of its product images and information, some manufacturing changes to packaging and/or ingredients may be pending update on our site. Although items may occasionally ship with alternate packaging, freshness is always guaranteed. We recommend that you read labels, warnings and directions of all products before use and not rely solely on the information provided by iHerb.

Supplement Facts
Serving Size: 1 Tablet
	Amount Per Serving:	% Daily Value
Vitamin D3 (as Cholecalciferol)	25 mcg (1,000 IU)	125%
Calcium (from Calcium Carbonate)	90 mg	7%

Century Vitamin D

Source: https://www.iherb.com/pr/21st-century-vitamin-d3-25-mcg-1-000-iu-300-tablets/43744

Share:

Read More

Why Is Vitamin D Important For Athletes

Why Is Vitamin D Important For Athletes

Vitamin D is often referred to as the sunshine vitamin, given that our primary source of this vitamin is exposure to the sun. Nevertheless, it is estimated that as much as 88% of the population receives less than the optimal amount of vitamin D.¹

The ability to synthesize vitamin D decreases as we age – by as much as 75%.

And, given that vitamin D is a fat-soluble vitamin, individuals who carry an excess amount of body fat can risk up to 55% of their vitamin D becoming trapped in fat cells and not available in the bloodstream.²

We often wrongly assume that athletes, because they train outdoors, receive enough sunlight to achieve their vitamin D needs. Although time in the sun is a significant factor, the sun is often not strong enough to meet vitamin D needs, even when the athlete spends seemingly adequate time in the sun.

In addition, skin pigmentation and sunscreen use can limit vitamin D production.

Besides the skin, only the eyes are the body's other organ directly exposed to sunlight. Therefore, the use of sunglasses, hats, helmets, and clothing can limit vitamin D production, even when time in the sun seems adequate.

Although it has already been established that athletes can be at risk for suboptimal vitamin D production, and the role of the vitamin in promoting normal health is well known, current research suggests that vitamin D might be of great interest to those athletes who have performance goals in mind.

In the body, vitamin D is associated with:^2-4

• Optimal calcium absorption*
• Bone and teeth health*
• Muscle strength and mass*
• Healthy immune function*
• Normal blood pressure*

• Promoting cell growth*
• Healthy neuromuscular function*
• A normal inflammatory response*
• Optimizing weight management *

What the research says about vitamin D in athletes

Research about vitamin D and athletes is an ever-expanding topic. Studies from the 1930s to the 1950s that linked better performances in summer months than winter months attributed the result to exposure to ultraviolet light. As this body of evidence grew, however, we began to tie ultraviolet light exposure to increases in vitamin D levels.

Athletes who train indoors, or in higher latitudes (north of Atlanta), or in winter months, or who use sunscreen, sunglasses, or other methods to shield the skin can have suboptimal vitamin D levels.

In fact, it is estimated that only 5% of collegiate athletes meet the recommended intake of vitamin D. ⁵

Even if athletes receive less vitamin D than is recommended, will supplemental vitamin D help? In 2016, researchers found that 70% of athletes tested had an inadequate vitamin D level at baseline. After a year of supplementing with vitamin D3 at 2,200 IU per day, 80% of those same athletes were shown to have an adequate vitamin D level.⁶

Further studies have examined the impact of vitamin D supplementation on performance. For example, a 2013 study from England in professional athletes and healthy active non-elite athletes showed an increase in sprint performance and vertical leap after eight weeks of supplementing 5,000 IU/day of vitamin D3.⁷

Muscles used in training and the recovery from that training are central to athletic performance. A 2013 study found that supplementing 4,000 IU vitamin D for 28 days had a positive impact on the recovery of peak isometric force after a physically stressful event.⁸

Because vitamin D plays a prominent role in bone health, it is of particular importance to athletes.

There have been several studies that link adequate vitamin D status to bone health and the prevention of bone injury in athletes. Studies also show that inadequate levels of vitamin D are linked to 3.6 times more stress fractures in young men.⁹ On the other hand, the inclusion of 800 IU/day of vitamin D in conjunction with calcium supplementation reduced the rate of stress fractures by 20% in female U.S. Navy recruits.¹⁰

A 2015 study looking at the correlation between vitamin D levels and the ability to keep a roster position in the National Football League found that in 80 NFL players, 77% had a deficient vitamin D level and there was a statistically significant relationship between a lower vitamin D level and the ability to make the regular season roster, often due to performance or injury.¹¹

One overlooked aspect of vitamin D is its role in immune function. The stress of training and competition travel places a burden not only on an athlete's bones and muscles, but also on the immune system. Every athlete knows competing when even the slightest bit ill will significantly diminish performance.

Vitamin D is essential for activating immune cells.

A common health issue impacting athletes is upper respiratory tract infections (URTIs). Recent studies in college athletes found that those athletes with lower vitamin D levels reported more frequent, more severe, and longer lasting URTIs than those who had higher levels of vitamin D.^5,12

A growing body of evidence supports having an adequate level of vitamin D in athletes not only to sustain normal health, but also to positively impact athletic performance. Given the high incidence of vitamin D insufficiency, the relatively few sources of vitamin D in the food supply, and the environmental factors that limit an athlete's ability to synthesize vitamin D, supplementation should be one of the more essential parts of an athlete's nutrition routine.

---

References

1. Bendik I, Friedel A, Roos F, et al. Vitamin D: a critical and essential micronutrient for human health. Front Physiol 2014;5:248.  doi: 10.3389/fphys.2014.00248
2. National Institutes of Health – Office of Dietary Supplements – Vitamin D – Fact Sheet for Health Professionals https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/ [accessed May 20, 2018]
3. Larson-Meyer D, Willis K. Vitamin D and athletes.Curr Sports Med Rep 2010;9(4):220-226.
4. Holick M. Vitamin D deficiency. N Engl J Med2007;357(3):266-281.
5. Halliday T, Peterson N, Thomas J, et al. Vitamin D status relative to diet, lifestyle, injury, and illness in college athletes. Med Sci Sports Exerc 2011;43(2):335-343.
6. Backx E, Tieland M, Maase K, et al. The impact of 1-year vitamin D supplementation on vitamin D status in athletes: a dose-response study. Eur J Clin Nutr 2016;70(9):1009-1014.
7. Close G, Russell J, Cobley J, et al. Assessment of vitamin D concentration in non-supplemented professional athletes and healthy adults during the winter months in the UK: implications for skeletal muscle function. J Sports Sci 2013;31(4):344-353.
8. Barker T, Schneider E, Dixon B, et al. Supplemental vitamin D enhances the recovery in peak isometric force shortly after intense exercise. Nutr Metab2013;10:69.
9. Ruohola J, Laaksi I, Ylikomi T, et al. Association between serum 25(OH)D concentrations and bone stress fractures in Finnish young men. J Bone Miner Res 2006;21(9):1483-1488.
10. Lappe J, Cullen D, Haynatzki G, et al. Calcium and vitamin D supplementation decreases incidence of stress fractures in female Navy recruits.J Bone Miner Res 2008;23(5):741-749.
11. Maroon J, Mathyssek C, Bost J, et al. Vitamin D profile in National Football League players. Am J Sports Med 2015;43(5):1241-1245.
12. He C, Handzlik M, Fraser W, et al. Influence of vitamin D status on respiratory infection incidence and immune function during four months of winter training in endurance sport athletes. Exerc Immunol Rev2013;19:86-101.

Why Is Vitamin D Important For Athletes

Source: https://www.thorne.com/take-5-daily/article/the-risks-of-being-vitamin-d-deficient-as-an-athlete

Share:

Read More

Dr Joe Prendergast Vitamin D

Dr Joe Prendergast Vitamin D

Clinic Management Software

Dr Joe Prendergast M.D.

Endocrinologist

1. My Story … 80 year old arteries at 37 years – 15 year old arteries at 87 !!
2. Cardiovascular disease – Arginine, Citrulline and Nitric Oxide.
3. Halting and Reversing Kidney Disease.
4. Arginine plus Nitric Oxide – the Trojan Horse.

Watch these 4 great movies on the HealthQuest Youtube Channel

80 year old arteries at age 37 … 15 year old arteries at 72 years of age!. Joe used the results of the research he conducted together with three pharmacologists (who subsequently won the Nobel prize in medicine for their research on Nitric Oxide and its vital cell signalling properties) to create a treatment program for atherosclerosis and circulation restoration. Dr. Joe was able to reverse his own life threatening problem with atherosclerosis completely.

Why We Age – The Role for Anti-oxidants and Arginine Dr Joe discusses the ageing process and how Antioxidants, Arginine, Citrulline and Nitric Oxide have a vital role to play in slowing the ageing process and improving life quality.

Dr Joe has found that supplying arginine, citrulline and vitamin D to patients with kidney disease prevents the disease from progressing and helps to reverse the condition. A patient in his 70's with type 1 diabetes (since he was 4 yrs old) developed kidney failure after a botched operation and was placed on dialysis. With Dr Joe using the arginine, citrulline and vitamin D treatment and the highly skilled young nephrologist conducting his dialysis and kidney treatment, the patient was able to come off dialysis as the kidneys healed.

L Arginine, Citrulline and Nitric Oxide accelerate the healing, improves the outcome and returns the patient to a normal life more rapidly after a heart attack. They also promote the reversal of the atherosclerotic plaques of cardiovascular disease.

Dr. Joseph Prendergast is an endocrinologist who specializes in the treatment of diabetes and cardiovascular disease. He serves on numerous boards including the California Medical Review Board, and he recently received an award from the American Medical Association for his humanitarian efforts. He has published more than 40 scientific papers and has lectured extensively in the United States and is considered to be one of the foremost leaders in his field.

Dr. Joe reversed his own problems with atherosclerosis completely … his arteries went from those of an 80 year old at age 37 to those of an 15 year old at age 72!

He then applied the same treatment to all of his own patients (80% of whom are diabetics) with absolutely amazing results. NOT ONE of his patients has been hospitalised for circulatory problems, heart attacks, strokes, peripheral neuropathy, gangrene, amputatations in over 17 years since he started applying the treatment to them … this is absolutely unheard of !!

Dr Joe Prendergast Vitamin D

Source: https://www.healthquest.net.au/dr-joe-prendergast-m-d/

Share:

Read More

What Vegetables And Fruits Have Vitamin D

What Vegetables And Fruits Have Vitamin D

10 Vitamin D–Rich Foods to Add to Your Diet

Fish, mushrooms, and several fortified foods can help you get your fix of the Sunshine Vitamin.

Reviewed: December 17, 2019

Tuna, swordfish, and salmon are all good sources of vitamin D.

Are you getting enough vitamin D in your diet? This nutrient is important for growing healthy cells, keeping your immune system humming to ward off illness, and aiding in calcium absorption so your bones stay strong. It also helps prevent the bone disease rickets in children, and with calcium, the so-called Sunshine Vitamin can help guard against osteoporosis in older adults, the National Institutes of Health (NIH) notes.

Vitamin D is produced in your body when the sun's ultraviolet rays hit your skin, and the recommended daily allowance (RDA) of vitamin D is 600 international units (IU), which is 15 micrograms (mcg) for most adults, according to the NIH. For those older than 80, the RDA is 800 IU (20 mcg).

Yet most people don't get enough vitamin D via sunlight, nor is food a good source of the nutrient, says Lori Zanini, RD, a Los Angeles–based dietitian.

People typically don't exceed 288 IU per day from diet alone. Even if you drink milk fortified with vitamin D, 8 fluid ounces (oz) has only 100 IU — one-sixth the amount that you need daily. No wonder 41.6 percent of Americans have a vitamin D deficiency, per a study. A vitamin D deficiency means you have 20 nanograms per milliliter or less of the nutrient in your blood. If you are nonwhite, obese, or do not have a college education, you may be at greater risk for being vitamin D deficient. Your healthcare provider can test your blood to find out for sure.

RELATED: Do You Need to Take a Vitamin D Supplement?

To get your fix, you can opt for supplements. Zanini recommends vitamin D3 (cholecalciferol), which is found in animal sources of food and is generally better absorbed in the body, though plant-derived vitamin D2 (ergocalciferol) is used in supplements as well. Yet research is mixed on whether vitamin D supplements offer concrete health benefits. Authors of a study published in January 2019 in The New England Journal of Medicine theorized that there is a reduced cancer risk for African Americans who take vitamin D supplements, as well as a significantly lower death rate in people with cancer who take them. But major studies published recently, including an October 2018 review in The Lancet, have not shown benefits from supplementation, despite prior hype about it.

"Getting vitamin D from food is a priority," says Zanini. Make sure your diet is rich in the following fare, so you can increase your intake.

889

Sockeye Salmon Is a Source of Protein

Not only is salmon a great option if you're looking for protein to add to your diet but it's also rich in the Sunshine Vitamin. According to the NIH, 3 oz of cooked sockeye salmon has about 447 IU of vitamin D. "In addition to vitamin D, salmon is a great addition to anyone's diet, with it also being a good source of healthy protein and omega-3 fatty acids," says Zanini. According to the NIH, fish offer two critical omega-3s: eicosapentaenoic acid and docosahexaenoic acid, which you must get through food. Omega-3s help keep your immune, pulmonary, endocrine, and cardiovascular systems healthy.

Add sockeye salmon to your dinner rotation with this flavorful Dijon-based recipe. Other cold-water fatty fish, like mackerel and sardines, also have similarly high levels of vitamin D, per the NIH.

RELATED: What Are the Health Benefits of Tilapia?

890

Enjoy Swordfish — in Moderation

Swordfish is another favorite of Zanini's. Three cooked ounces provide 566 IU per serving, which nearly gets you to your daily recommended intake of vitamin D, according to the NIH. "The American Heart Association [AHA] recommends eating at least two servings of fish per week, and this fish is versatile and tasty," she adds. The AHA advises children and pregnant women to avoid large fish, such as swordfish, because they have higher levels of mercury contamination than smaller, less long-lived species. Yet the health benefits for older adults in particular outweigh the risks, according to the organization.

Try swordfish in kebabs complete with onions, green bell peppers, mushrooms, and cherry tomatoes.

891

Canned Tuna Packs More Than 25 Percent of Your Daily Goal

892

Eat Mushrooms for a Versatile Vitamin D Punch

While mushrooms don't naturally offer a high amount of vitamin D, some are treated with UV light, providing a larger dose of the nutrient as a result. The vitamin D amounts will vary depending on the amount of UV light the mushrooms are exposed to, according to the Agricultural Research Service. A serving has between 124 and 1,022 IU per 100 grams (g).

Growers such as Monterey Mushrooms produce varieties high in vitamin D, but you have to read the labels. Once you have them, add sautéed mushrooms to eggs or fish for a meal even richer in vitamin D. Or make a more substantial mushroom dish, such as veggie-stuffed portobellos.

893

Fortified Milk Offers a Double Whammy: Vitamin D and Calcium

In addition to being an excellent source of calcium, 8 fluid ounces (fl oz) of milk has between 115 and 124 IU of vitamin D, the NIH notes. Be sure to check the label of your favorite brand for the exact amount. Fortified plant-based milks, such as soy and almond, can provide similar amounts of vitamin D, as well.

Enjoy a cold 8 oz glass of your preferred fortified milk straight up, blend it into a smoothie, or use it to whip up your choice of coffee drink.

RELATED: 9 Best and Worst Milks for Your Cholesterol Levels

894

Fortified Orange Juice Can Give You a Healthy Start to the Day

One cup (8 fl oz) of fortified orange juice can add up to 137 IU of vitamin D to your daily total, though the NIH recommends checking the label for exact numbers because counts can vary. Serve a glass of OJ with breakfast or use it in this mango-strawberry smoothie recipe, a delicious and portable morning meal. Keep in mind that it's generally healthiest to enjoy whole fruit rather than its juice form, since the former still contains filling fiber, so drink juice in moderation. If you have a health condition for which you need to watch your carbohydrate and sugar intake, such as diabetes, it may be best to get your vitamin D from another source. Work with your healthcare team to figure out how much, if any, OJ is right for your diet.

895

Fortified Yogurt Makes for a Gut-Healthy Snack

Yogurt is a convenient, tasty snack — and when consumed plain or with fresh fruit, it's healthy, too. This type of dairy is an excellent source of good-for-the-gut probiotics, and reaching for a fortified variety will knock off between 10 and 20 percent of your daily requirement of vitamin D, depending on the brand. Many fortified varieties are flavored (meaning they're likely to be sugar bombs), so read the nutrition label to find out what you're getting. The AHA recommends a max of 9 teaspoons (tsp) or 26 g of added sugar for men per day and a max of 6 tsp or 25 g of added sugar for women per day.

Try cooking a meal with plain yogurt for a vitamin D–enhanced entrée: This Middle Eastern–style chopped vegetable salad includes greens, herbs, and grains and also uses a cup of plain yogurt. It is a cooling alternative to a hot dish.

RELATED: Eat These 3 Foods for a Healthy Gut

896

Cereal Can Be Fortified With Vitamin D, and Oatmeal Offers Fiber

A packet of unsweetened, fortified oatmeal can add a solid dose of vitamin D to your diet. Ready-to-eat fortified cereal typically gives you 40 IU of vitamin D per serving, per the NIH, but it may provide more if you choose a more heavily fortified cereal, like Raisin Bran, which has 60.2 IU per cup, notes the U.S. Department of Agriculture.

Fortified cereal can be a solid base for a nutrient-rich, high-fiber meal — especially if you add fortified low-fat or fat-free milk to your bowl for an extra 60 IU per half cup. Or you can be more adventurous and make a breakfast cookie that includes both fortified cereal and vitamin D–fortified margarine.

897

Eggs Contain Protein and Immunity-Boosting Benefits

898

Sardines Give You Calcium, Omega-3s, and Protein

Buying fresh fish can be pricey. If that's holding you back, give canned sardines a try. They're more affordable than other forms of fish and are high in protein, heart-healthy omega-3 fatty acids, calcium, and vitamin D. Two sardines from a can offer 46 IU of the vitamin, or 12 percent of your daily value, according to the NIH. The underrated fish works well on top of salads, as well as in pasta sauces and stews.

What Vegetables And Fruits Have Vitamin D

Source: https://www.everydayhealth.com/foods-high-vitamin-d/

Share:

Read More

Vitamin D 10mcg In Units

Vitamin D 10mcg In Units

Vitamin D is needed to support healthy bone development and to prevent rickets, a condition that causes weak or deformed bones. Vitamin D deficiency rickets among breastfed infants is rare, but it can occur if an infant does not receive additional vitamin D from foods, a vitamin D supplement, or adequate exposure to sunlight.

Do infants get enough vitamin D from breast milk?

Breast milk alone does not provide infants with an adequate amount of vitamin D. Shortly after birth, most infants will need an additional source of vitamin D.

To avoid developing a vitamin D deficiency, the Dietary Guidelines for Americans and American Academy of Pediatrics recommend breastfed and partially breastfed infants be supplemented with 400 IU per day of vitamin D beginning in the first few days of life. Families who do not wish to provide a supplement directly to their infant should discuss with a healthcare provider the risks and benefits of maternal high dose supplementation options.

Once a child has started eating solid foods, parents can make sure their child is getting enough vitamin D from foods or supplements.

Why are infants at risk for vitamin D deficiency?

The risk for vitamin D deficiency is increased when there is limited exposure to sunlight or when an infant is not consuming an adequate amount of vitamin D. Although reducing sun exposure is important for preventing cancer, it also decreases the amount of vitamin D that a person can make from sunlight.

Other factors that decrease the amount of vitamin D a person can make from sunlight include:

• Living at high latitudes (closer to the polar regions), particularly during winter months.
• High levels of air pollution.
• Dense cloud covering.
• The degree to which clothing covers the skin.
• Use of sunscreen.
• Darker skin types.

Vitamin D 10mcg In Units

Source: https://www.cdc.gov/breastfeeding/breastfeeding-special-circumstances/diet-and-micronutrients/vitamin-d.html/

Share:

Read More