Observational studies support an association between higher serum 25 OH D levels and a lower risk of CVD incidence and mortality. For example, a meta-analysis included 34 observational studies that followed , participants mean age greater than 50 years for 1.
The results showed that baseline serum 25 OH D levels were inversely associated with total number of CVD events including myocardial infarction, ischemic heart disease, heart failure, and stroke and mortality risk [ ]. Another large observational study that followed , adults from Denmark for 0—7 years found that levels of 25 OH D that were low about Other meta-analyses of prospective studies have found associations between lower vitamin D status measured by serum 25 OH D levels or vitamin D intakes and an increased risk of ischemic stroke, ischemic heart disease, myocardial infarction, and early death [ , ].
In contrast to the observational studies, clinical trials have provided little support for the hypothesis that supplemental vitamin D reduces the risk of CVD or CVD mortality.
For example, a 3-year trial in New Zealand randomized 5, adults mean age Vitamin D supplementation had no effect on the incidence rate of myocardial infarction, angina, heart failure, arrhythmia, arteriosclerosis, stroke, venous thrombosis, or death from CVD. Similarly, the VITAL clinical trial described above found that vitamin D supplements did not significantly decrease rates of heart attacks, strokes, coronary revascularization, or deaths from cardiovascular causes [ 91 ].
High serum cholesterol levels and hypertension are two of the main risk factors for CVD. The data on supplemental vitamin D and cholesterol levels are mixed, as shown in one meta-analysis of 41 clinical trials in a total of 3, participants mean age 55 years. The results of this analysis showed that 0. Studies of the effects of vitamin D supplements on hypertension have also had mixed findings.
In contrast, another meta-analysis of 30 clinical trials in 4, participants mean age Another meta-analysis of genetic studies in , participants primarily adults found that a low vitamin D status increased blood pressure and hypertension risk in people with genetic variants associated with low endogenous production of 25 OH D [ ].
Depression Vitamin D is involved in various brain processes, and vitamin D receptors are present on neurons and glia in areas of the brain thought to be involved in the pathophysiology of depression [ ]. A systematic review and meta-analysis of 14 observational studies that included a total of 31, adults mean age ranging from Clinical trials, however, do not support these findings.
For example, a meta-analysis of 9 trials with a total of 4, adult participants diagnosed with depression or depressive symptoms found no significant reduction in symptoms after supplementation with vitamin D [ ]. They also had different study durations 5 days to 5 years , mean participant ages range, 22 years to 75 years , and baseline 25 OH D levels; furthermore, some but not all studies administered concurrent antidepressant medications.
Three trials conducted since that meta-analysis also found no effect of vitamin D supplementation on depressive symptoms. Most participants had minimal or mild depression, had a low mean baseline 25 OH level of The groups showed no significant differences in the incidence and recurrent rates of depression, clinically relevant depressive symptoms, or changes in mood scores. Overall, clinical trials did not find that vitamin D supplements helped prevent or treat depressive symptoms or mild depression, especially in middle-aged to older adults who were not taking prescription antidepressants.
No studies have evaluated whether vitamin D supplements may benefit individuals under medical care for clinical depression who have low or deficient 25 OH D levels and are taking antidepressant medication. Multiple sclerosis MS is an autoimmune disease of the central nervous system that damages the myelin sheath surrounding and protecting nerve cells in the brain and spinal cord. This damage hinders or blocks messages between the brain and body, leading to clinical features, such as vision loss, motor weakness, spasticity, ataxia, tremor, sensory loss, and cognitive impairment [ , ].
Some people with MS eventually lose the ability to write, speak, or walk. The geographical distribution of MS around the world is unequal. Few people near the equator develop the disease, whereas the prevalence is higher further north and south. This uneven distribution has led to speculation that lower vitamin D levels in people who have less sunlight exposure might predispose them to the disease [ ].
Many epidemiological and genetic studies have shown an association between MS and low 25 OH D levels before and after the disease begins [ ]. Observational studies suggest that adequate vitamin D levels might reduce the risk of contracting MS and, once MS is present, decrease the risk of relapse and slow the disease's progression [ ].
One study, for example, tested 25 OH D levels in 1, women in Finland an average of 9 years before their MS diagnosis and compared their outcomes with those of 2, similar women who did not develop MS [ ]. More than half the women who developed MS had deficient or insufficient vitamin D levels. Two earlier prospective studies of similar design—one in the United States with non-Hispanic White individuals [ ] and the other with individuals in northern Sweden [ ]—found that levels of 25 OH D greater than No clinical trials have examined whether vitamin D supplementation can prevent the onset of MS, but several have investigated whether supplemental vitamin D can help manage the disease.
A Cochrane review analyzed 12 such trials that had a total of participants with MS; the reviewers judged all of these trials to be of low quality [ ]. Overall, vitamin D supplementation, when compared with placebo administration, had no effect on relevant clinical outcomes, such as recurrent relapse or worsened disability.
Experts have reached no firm consensus on whether vitamin D can help prevent MS given the lack of clinical trial evidence [ ]. In addition, studies have not consistently shown that vitamin D supplementation tempers the signs and symptoms of active MS or reduces rates of relapse. Type 2 diabetes Vitamin D plays a role in glucose metabolism. It stimulates insulin secretion via the vitamin D receptor on pancreatic beta cells and reduces peripheral insulin resistance through vitamin D receptors in the muscles and liver [ ].
Vitamin D might be involved in the pathophysiology of type 2 diabetes through its effects on glucose metabolism and insulin signaling as well as its ability to reduce inflammation and improve pancreatic beta-cell function [ , ]. Observational studies have linked lower serum 25 OH D levels to an increased risk of diabetes, but their results might have been confounded by the fact that many participants were overweight or obese and were therefore more predisposed to developing diabetes and having lower 25 OH D levels [ 1 ].
A review of 71 observational studies in adults with and without type 2 diabetes from 16 countries found a significant inverse relationship between vitamin D status and blood sugar levels in participants who did and did not have diabetes [ ].
In contrast to observational studies, clinical trials provide little support for the benefits of vitamin D supplementation for glucose homeostasis.
In the 54 participants who completed the study, vitamin D supplementation did not improve insulin sensitivity or insulin secretion in comparison with placebo. Vitamin D had no significant effects on glucose homeostasis, insulin secretion or resistance, or hemoglobin A1c levels a measure of average blood sugar levels over the previous 2—3 months , irrespective of the study population, vitamin D dose, or trial quality.
Several trials have investigated whether vitamin D supplementation can prevent the transition from prediabetes to diabetes in patients with adequate 25 OH D levels, and all have had negative results. In a trial in Norway, men and women aged 25—80 years mean age 62 years with prediabetes received mcg 20, IU vitamin D 3 or a placebo each week for 5 years [ ].
The results showed no significant differences in rates of progression to type 2 diabetes; in serum glucose, insulin, or hemoglobin A1c levels; or in measures of insulin resistance. The largest trial to date of vitamin D supplements for diabetes prevention randomized 2, men and women aged 25 years and older mean age 60 years with prediabetes who were overweight or obese mean BMI of Vitamin D did not significantly prevent the development of diabetes in comparison with placebo.
Studies have also assessed the value of vitamin D supplementation for managing diabetes, and they have found that the vitamin offers limited benefits. One meta-analysis of 20 clinical trials compared the effects of 0. However, the supplementation had no significant effects on fasting blood glucose, hemoglobin A1c, or fasting insulin levels.
Clinical trials to date provide little evidence that vitamin D supplementation helps maintain glucose homeostasis, reduces the risk of progression from prediabetes to type 2 diabetes, or helps manage the disease, particularly in vitamin D-replete individuals. Weight loss Observational studies indicate that greater body weights are associated with lower vitamin D status, and obese individuals frequently have marginal or deficient circulating 25 OH D levels [ ].
However, clinical trials do not support a cause-and-effect relationship between vitamin D and weight loss. A systematic review and meta-analysis of 15 weight-loss intervention studies that used caloric restriction, exercise, or both, but not necessarily vitamin D supplementation or other treatments, found that people who lost weight had significantly greater increases in serum 25 OH D levels than those who maintained their weight [ ].
However, a meta-analysis of 12 vitamin D supplementation trials including 5 in which body composition measurements were primary outcomes found that vitamin D supplements without calorie restriction did not affect body weight or fat mass when the results were compared with those of placebo [ ].
Overall, the available research suggests that consuming higher amounts of vitamin D or taking vitamin D supplements does not promote weight loss. Excess amounts of vitamin D are toxic. Because vitamin D increases calcium absorption in the gastrointestinal tract, vitamin D toxicity results in marked hypercalcemia total calcium greater than Hypercalcemia, in turn, can lead to nausea, vomiting, muscle weakness, neuropsychiatric disturbances, pain, loss of appetite, dehydration, polyuria, excessive thirst, and kidney stones.
In extreme cases, vitamin D toxicity causes renal failure, calcification of soft tissues throughout the body including in coronary vessels and heart valves , cardiac arrhythmias, and even death. Vitamin D toxicity has been caused by consumption of dietary supplements that contained excessive vitamin D amounts because of manufacturing errors, that were taken inappropriately or in excessive amounts, or that were incorrectly prescribed by physicians, [ ].
Experts do not believe that excessive sun exposure results in vitamin D toxicity because thermal activation of previtamin D 3 in the skin gives rise to various non-vitamin D forms that limit formation of vitamin D 3.
Some vitamin D 3 is also converted to nonactive forms [ 1 ]. However, other, shorter from 24 weeks to 5 years clinical trials of vitamin D supplementation alone or with calcium in adults found greater risks of hypercalcemia and hypercalciuria, but not of kidney stones [ , ].
While acknowledging that signs and symptoms of toxicity are unlikely at daily intakes below mcg 10, IU , the FNB noted that even vitamin D intakes lower than the ULs might have adverse health effects over time. Vitamin D supplements may interact with several types of medications. A few examples are provided below. Individuals taking these and other medications on a regular basis should discuss their vitamin D intakes and status with their healthcare providers.
Statins Statin medications reduce cholesterol synthesis. Because endogenous vitamin D is derived from cholesterol, statins may also reduce vitamin D synthesis [ ]. These medications can reduce calcium absorption and impair vitamin D metabolism [ ]. Thiazide diuretics Thiazide diuretics e. The combination of these diuretics with vitamin D supplements which increase intestinal calcium absorption might lead to hypercalcemia, especially among older adults and individuals with compromised renal function or hyperparathyroidism [ , , ].
The federal government's Dietary Guidelines for Americans notes that "Because foods provide an array of nutrients and other components that have benefits for health, nutritional needs should be met primarily through foods. In some cases, fortified foods and dietary supplements are useful when it is not possible otherwise to meet needs for one or more nutrients e.
For more information about building a healthy dietary pattern, refer to the Dietary Guidelines for Americans and the U. Department of Agriculture's MyPlate. This fact sheet by the Office of Dietary Supplements ODS provides information that should not take the place of medical advice. We encourage you to talk to your healthcare providers doctor, registered dietitian, pharmacist, etc. Any mention in this publication of a specific product or service, or recommendation from an organization or professional society, does not represent an endorsement by ODS of that product, service, or expert advice.
Updated: August 17, History of changes to this fact sheet. Find ODS on:. Strengthening Knowledge and Understanding of Dietary Supplements. Health Information Health Information. Vitamin D. Present Knowledge in Nutrition, 10th ed. Washington DC: Wiley-Blackwell, Jones G.
Modern Nutrition in Health and Disease, 11th ed. Intestinal absorption of vitamin D: A systematic review. Nutr Rev ; Vitamin D assays and the definition of hypovitaminosis D. Br J Clin Pharmacol ; Screening for vitamin deficiency in adults: U. Preventive Services Task Force recommendation statement. Ann Intern Med ; The importance of hydroxyvitamin D assay standardization and the Vitamin D Standardization Program. Vitamin D: moving forward to address emerging science.
Nutrients , 9, ; doi Public Health Nutrition ; J Clin Endocrinol Metab ; Vitamin D deficiency. N Engl J Med ; The vitamin D paradox in Black Americans: A systems-based approach to investigating clinical practice, research, and public health—expert panel meeting report. BMC Proceedings, ;12 Suppl 6 Comparative analysis of nutritional guidelines for vitamin D.
Nat Rev Endocrinol ; Vitamin D and Health. Vitamin D in foods: An evolution of knowledge. Elsevier, Food and Drug Administration. Food additives permitted for direct addition to food for human consumption; vitamin D2 mushroom powder. Federal Register ; Vitamin D bioavailability: State of the art. Crit Rev Food Sci Nutr ; Including food hydroxyvitamin D in intake estimates may reduce the discrepancy between dietary and serum measures of vitamin D status. J Nutr ; Relative effectiveness of oral hydroxyvitamin D3 and vitamin D3 in raising wintertime serum hydroxyvitamin D in older adults.
Am J Clin Nutr ; Assessing the vitamin D status of the US population. Vitamin D for milk and milk alternatives. January 4, Department of Agriculture, Agricultural Research Service.
FoodData Central. Food labeling: Revision of the Nutrition and Supplement Facts labels. Federal Register 81 Hossein-nezhad A, Holick MF. Vitamin D for health: A global perspective. Mayo Clin Proc ; Department of Health and Human Services. Washington, DC: U. Holick MF. Vitamin D: the underappreciated D-lightful hormone that is important for skeletal and cellular health.
Curr Opin Endocrinol Diabetes ; Nutritional rickets among children in the United States: review of cases reported between and Comparison of vitamin D2 and vitamin D3 supplementation in raising serum hydroxyvitamin D status: A systematic review and meta-analysis. Bioavailability of vitamin D2 and D3 in healthy volunteers, a randomised placebo-controlled trial. J Clin Endocrin Metab ; Long-term vitamin D3 supplementation is more effective than vitamin D2 in maintaining serum hydroxyvitamin D status over the winter months.
Br J Nutr ; Supplemental hydroxycholecalciferol is more effective than cholecalciferol in raising serum hydroxyvitamin D concentrations in older adults. Is calcifediol better than cholecalciferol for vitamin D supplementation?
Osteoporos Int ; Dietary Supplement Label Database. Percent reporting and mean amounts of selected vitamins and minerals food and beverages and dietary supplements by gender and age, in the United States, Usual nutrient intake from foods and beverages, by gender and age. Trends in use of high-dose vitamin D supplements exceeding or International Units daily, JAMA ; The emerging issue of hydroxyvitamin D in foods.
Vitamin D status in the United States, Lancet ; Global consensus recommendations on prevention and management of nutritional rickets. Nutritional rickets and osteomalacia in the twenty-first century: Revised concepts, public health, and prevention strategies. Curr Osteoporos Rep ; Nutritional rickets among children in the United States: Review of cases reported between and Increasing incidence of nutritional rickets: A population-based study in Olmsted County, Minnesota.
Vitamin D-deficiency rickets among children in Canada. CMAJ ; Vitamin D, cod-liver oil, sunlight, and rickets: A historical perspective. Pediatrics ;e Nutritional rickets around the world: An update. Paediatr Int Child Health ; Clinical management of low vitamin D: A scoping review of physicians' practices.
Nutrients Apr 16;10 4. Am J Med ; Considerations in dietetic counseling for vitamin D. J Acad Nutr Diet ; Screening for vitamin D deficiency: Systematic review for the U. Preventive Services Task Force recommendation. Evidence Synthesis Number June Picciano MF. Nutrient composition of human milk. Pediatr Clin North Am ; Prevention of rickets and vitamin D deficiency in infants, children, and adolescents.
Pediatrics ; Maternal vitamin D status: Effect on milk vitamin D content and vitamin D status of breastfeeding infants. Adv Nutr ; The 'sunshine vitamin': benefits beyond bone? J Natl Cancer Inst ; Adherence to vitamin D intake guidelines in the United States.
Vitamin D synthesis following a single bout of sun exposure in older and younger men and women. According to one review, This number goes up to It directly interacts with the cells that are responsible for fighting infection 6. If you often become sick, especially with colds or the flu , low levels of vitamin D may be a contributing factor.
Several large observational studies have shown a link between a deficiency and respiratory tract infections such as colds, bronchitis, and pneumonia 7 , 8. A number of studies have found that taking vitamin D supplements at a dosage of up to 4, IU daily may reduce your risk of developing a respiratory tract infection 9 , 10 , Vitamin D plays important roles in immune function. One of the most common symptoms of a deficiency is an increased risk of illness or infections.
Feeling tired can have many causes, and vitamin D deficiency may be one of them. Case studies have shown that very low blood levels of vitamin D can cause fatigue that can have a severe negative effect on quality of life In a study including 39 children, low vitamin D levels were associated with poor sleep quality, shorter sleep duration, and delayed bedtimes One observational study in female nurses also found a strong connection between low vitamin D levels and self-reported fatigue.
Interestingly, several studies have also found that supplementing with vitamin D could reduce the severity of fatigue in people with a deficiency 15 , For more information on how to reduce fatigue, consider reading about the 11 best vitamins and supplements to boost energy.
Excessive fatigue and tiredness may be a sign of vitamin D deficiency. Taking supplements may help improve energy levels. Large observational studies have found a relationship between a deficiency and chronic lower back pain 17 , One study including 98 people with lower back pain found that increased pain severity was associated with lower levels of vitamin D Another review of 81 studies also found that people with arthritis, muscle pain, and chronic widespread pain tended to have lower levels of vitamin D than people without these conditions Low blood levels of vitamin D may be a cause or contributing factor to bone pain and lower back pain.
In review studies, researchers have linked vitamin D deficiency to depression, particularly in older adults 21 , On the other hand, most of the controlled trials, which carry more scientific weight than observational studies, did not show a link between the two However, the researchers who analyzed the studies noted that the dosages of vitamin D in controlled studies were often very low.
Some studies have shown that giving vitamin D to people who are deficient helps improve depression, including seasonal depression, which typically occurs during the colder months 24 , Depression is associated with low vitamin D levels, and some studies have found that supplementing improves mood.
In fact, results from a test-tube study suggest that the vitamin increases the production of compounds that are crucial for forming new skin as part of the wound-healing process One review of four studies found that vitamin D deficiency compromised certain aspects of healing in people who had dental surgery It found that those with severe vitamin D deficiency were more likely to have higher levels of inflammatory markers that can jeopardize healing However, one study involving 60 people with diabetes-related foot ulcers found that taking a vitamin D supplement for 12 weeks significantly improved wound healing compared with a control group Inadequate vitamin D levels may lead to poor wound healing following surgery, injury, or infection.
Vitamin D plays a crucial role in calcium absorption and bone metabolism. Many older people who are diagnosed with bone loss believe they need to take more calcium.
However, they may be deficient in vitamin D as well. Low bone mineral density is an indication that your bones have lost calcium and other minerals. This places older adults, especially women, at an increased risk of fractures. In a large observational study in more than 1, middle-age menopausal or postmenopausal women, researchers found a strong link between low vitamin D levels and low bone mineral density It means that your result is normal within the testing population, but if you are at the lower end of the range it may not be sufficient for optimal vitamin D status.
Whatever your number and health status, work with your provider to achieve the optimal level for you, through supplementation, nutrition, or getting more sun exposure. Your choice! When in doubt, give our ZRT Clinical Consultants a call and they can help walk you through the ever-evolving and sometimes conflicting data regarding ideal vitamin D levels. Call us at Twitter Facebook LinkedIn Instagram.
Reference Range The reference range, a term often used in conjunction with laboratory testing, is a set of values that include the upper and lower limits of a lab test based on a group of otherwise healthy individuals. Categories: Vitamin D. Please enable JavaScript to view the comments powered by Disqus. Alison McAllister Dr. Allison Smith Dr. Beth Baldwin Dr. David Zava Dr.
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