Yes and no. Body size is more influential than sex when it comes to vitamin D intake recommendations, Foroutan says. On average, men weigh more than women.
However, the relative amount of body fat an individual has may be more pertinent, since vitamin D is stored in body fat. A study published online in November in PLoS One aimed to analyze the effect that body mass index may have on vitamin D dosing targets.
Findings suggested that participants who were obese needed 2 to 3 times more vitamin D than their normal-weight counterparts. But men and women are at different risks for various chronic conditions, which means adjusting your vitamin D target may be helpful for managing symptoms or delaying disease progression. People who live in colder climates generally need more vitamin D than those who live closer to the equator, but among all geographic locations, people with darker skin tones often need more of the vitamin than those with lighter skin.
Indeed, people with highly pigmented skin who live in cold climates are considered to be at a particularly high risk of vitamin D deficiency , according to a study published in June in the Journal of the American Academy of Dermatology.
While wearing sunscreen daily is key to help prevent sunburns, premature aging, and skin cancer , this healthy habit can also affect how much vitamin D your skin synthesizes from the sun. To get your fix, aim to spend 10 to 15 minutes outdoors without sunscreen, Foroutan says.
Generally, research on the role vitamin D may play in disease prevention and management is murky. Particularly with regard to the benefits of taking supplements, most of the studies have been observational or done on small groups or both. Until recent years, there has been a lack of large randomized, controlled trials, which are the gold standard for medical research because such studies point to cause-and-effect relationships between factors.
The data now coming in from such trials fails to back up previous claims about the benefits of vitamin D supplementation. Bone Health As mentioned, vitamin D helps in the absorption of calcium in the gut.
Type 2 Diabetes Observational studies have associated low vitamin D levels with a higher risk of developing type 2 diabetes. A dose of 4, IU of vitamin D per day did not result in a significantly lower risk of developing type 2 diabetes compared with a placebo. Cardiovascular Disease Taking vitamin D supplements does not reduce the risk of heart attack, stroke, or death from heart disease, according to the findings of a randomized, controlled clinical trial involving more than 25, participants that was published in the aforementioned January in The New England Journal of Medicine.
Cancer In the same study, researchers found that vitamin D supplementation was not found to reduce the risk of cancer in participants overall. However, those who had developed cancer and were taking vitamin D were less likely to die early than those who took a placebo. Researchers also found a possible reduction in cancer risk for African Americans, and they called for further study to confirm those results. Rheumatoid arthritis RA A small observational study of 44 people with RA and 25 controls found that vitamin D deficiency appeared to be more prevalent among people with RA , suggesting these people may benefit from taking a supplement.
Mood Disorders Vitamin D is an established therapy for seasonal depression, also called seasonal affective disorder , according to the National Institute of Mental Health.
Thyroid Disease The connection between vitamin D and people with hypothyroidism seems clearer, though larger-scale research is necessary. They can perform a blood test to see if you may benefit from upping your intake of vitamin D—rich foods like salmon, fortified milk, and eggs , or taking a vitamin D supplement, according to MedlinePlus. Additional reporting by Melinda Carstensen and Jamie Ludwig. By subscribing you agree to the Terms of Use and Privacy Policy. Health Topics.
Health Tools. In adults, a vitamin D deficiency may 17 , 18 , 19 :. In children, a severe vitamin D deficiency can cause delays in growth and rickets, a disease where the bones become soft. Furthermore, vitamin D deficiency is linked with several cancers, type 1 diabetes, multiple sclerosis, high blood pressure, and thyroid problems 17 , 20 , Vitamin D deficiency is prevalent worldwide but occurs at higher rates in specific populations.
A deficiency in vitamin D is linked to various health problems. This is only a partial list of factors that help determine the amount of vitamin D a person needs.
One study involving healthy adults showed that a daily intake of 1,—1, IU was needed to maintain sufficient blood levels 23 , People who are overweight or have obesity may also need higher amounts of vitamin D 27 , All things considered, a daily vitamin D intake of 1,—4, IU, or 25— micrograms, should be enough to ensure optimal blood levels in most people. Make sure not to take more than that without consulting with a healthcare professional However, some studies suggest that a higher daily intake of 1,—4, IU 25— micrograms is needed to maintain optimal blood levels.
Blood levels of vitamin D are assessed by measuring 25 OH D in the blood, which is the storage form of vitamin D in the body A committee at the IOM did not find higher blood levels to be associated with any additional health benefits Vitamin D intake is generally quite low, since very few foods contain significant amounts Foods that do contain vitamin D include fatty fish like salmon as well as fish liver oils.
Egg yolks also contain small amounts, and in some countries milk and cereals are enriched with vitamin D The main sources of vitamin D are sunshine, fatty fish, egg yolks, fish liver oils, fortified foods, and supplements. Additionally, the amount of sunlight needed varies. Older individuals and dark-skinned people tend to produce less vitamin D in the skin 34 , Also, geographic location and season are relatively crucial because vitamin D production is affected in places further away from the equator 35 , The Skin Cancer Organization recommends that you only do this two to three times weekly, followed by sunscreen use.
Keep in mind that the same process that helps your body synthesize vitamin D can cause DNA damage, sunburn, genetic mutations. This can cause wrinkles to develop and increase your risk for skin cancer The RDA and AI values are typically based on total daily intake from foods, beverages, and, if needed, supplements. There is an increased risk of an adverse event when exceeding the UL - although sometimes the risk is acceptable when the nutrient is used in medical treatment, such as to treat a severe deficiency.
The DVs are shown in green in the table below. Note : The FDA initially gave large manufacturers and small manufacturers until July of and , respectively, to update their labels with the new DVs. However, in September , it extended these deadlines to January 1 of and , respectively.
Until then, the old DVs may still appear. ConsumerLab's Dr. Tod Cooperman explains why labels on many vitamin and mineral supplements are outdated and wrong and why you should use the information on this page to find your daily nutritional requirements.
Get additional information about each nutrient, including ConsumerLab's independent tests and reviews of supplements, using the "Report" links above. Also, see reports on Multivitamins and other popular supplements. Until all labels are updated to reflect the latest rules by January , be aware that a product listing mcg of synthetic folate, such as folic acid, actually provides about mcg to mcg DFE.
Consequently, if a product made with folic acid lists 1, mcg DFE, it only contains about mcg of folic acid which is far below the adult UL of 1, mcg of synthetic folate. AIs established for potassium in were reduced in due to a change in approach, focusing specifically on nutritional adequacy.
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