Got Vitamin D ?
3 million Americans are estimated to be vitamin D-deficient. Why is that and what does that mean for you?
According to 2011 statistics, almost 1 in 3 Americans don’t have high enough vitamin D blood levels to maintain good bone health, and this deficiency can be found in all ethnicities and age groups. In this article, we’ll describe why exactly we need vitamin D and why deficiency happens to be so common.
For more information about best-selling vitamin D supplements and tests on their quality and safety, see Labdoor’s full reports and rankings here.
First, what is vitamin D good for?
Vitamin D helps us absorb calcium from food, and calcium, as we all know, supports strong bones so they don’t become thin, brittle, and prone to fractures. On top of that, vitamin D is crucial for cell growth and neural and immune health.
Our cells need direct interaction with vitamin D for proper growth and maturation. Our neurons specifically need vitamin D because nerve to nerve communication relies on the calcium we absorb with vitamin D. In fact, nerve pain is considered an early warning sign of vitamin D deficiency and a link has been found between vitamin D deficiency and neurological diseases like Alzheimer’s.
Vitamin D also helps to ensure that our immune system is fully activated to combat bacterial and viral bugs. For example, why do you think the flu so prevalent in the winter? There’s actually research evidence that our immune system becomes compromised in the winter because we get less sun and our vitamin D levels drop.
Why is vitamin D deficiency so common?
1) The American diet is typically low in vitamin D.
Dietary sources of vitamin D include fatty fish like salmon and tuna, eggs, mushrooms, and fortified foods like milk and breakfast cereals. However, the amount of vitamin D in fortified products, 50–100 IU per 8 ounces of milk, makes up only a small percentage of an adult’s recommended dietary allowance (RDA), 600 IU/day. This is even more so the case with older adults (70+) with an RDA of 800 IU/day.
2) Our exposure to the sun, which activates vitamin D production in our bodies, isn’t (and shouldn’t be) enough to meet our full vitamin D need.
Higher latitudes like Boston versus Florida get less vitamin D-producing UVB light, especially in the winter. Those living in big cities and working office jobs are also at higher risk. Air pollution absorbs UVB radiation, so it doesn’t reach us as well, and staying indoors limits our access to it even more. Finally, how much UVB exposure we need depends on our skin tone. Those with darker skin need more to produce the same amount of vitamin D as a person with lighter skin.
Despite the importance of sun for vitamin D synthesis, you should limit how much radiation you get from the sun and tanning beds. UV radiation is responsible for most of of the 1.5 million cases of skin cancer in the U.S. per year.
3) Vitamin D is a fat-soluble vitamin, which makes it hard for some people to process or use it.
This is common for people with diseases of the gut like celiac disease, pancreatitis, Crohn’s disease, and cystic fibrosis. Liver and kidney disease can also prevent vitamin D from being efficiently converted to its active form. People who are obese may also have more trouble using vitamin D since greater amounts of subcutaneous fat sequester the vitamin and impair release into the blood.
Is vitamin D supplementation right for me?
The definitive way to see if you are vitamin D-deficient is for your doctor to perform a blood test for you. If you are deficient or at higher risk, supplements might be a good option. To choose between brands, you’ll want to make sure you:
- Get enough, but not too much — Because vitamin D is fat-soluble, we accumulate it in our tissues. Too much can lead to weight loss, heart palpitations, and damage to your heart, blood vessels, and kidneys.
- Get the right kind — There’s some argument that vitamin D2 might be better absorbed than vitamin D3. It appears in research that nutritional doses of D2 and D3 are equivalent, but at high doses, D2 is less effective.
- Get one that’s been tested to be effective and safe — For that, check out Labdoor’s full rankings on 20 best-selling vitamin D supplements here. As always, please consult your doctor when starting any new supplements, especially if you are taking any medications or have any health problems.
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Other Sources:
- 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
- Dietary Reference Intakes for Calcium and Vitamin D — The Institute of Medicine
- Vitamin D and Health — Harvard School of Public Health
- Vitamin D: How Much Is Enough? — Harvard School of Public Health
- Vitamin D: an Evidence-Based Review — Journal of the American Board of Family Medicine
- The Protective Role of Melanin Against UV Damage in Human Skin — Photochemistry and Photobiology
- Vitamin D — Office of Dietary Supplements of the National Institutes of Health
- Vitamin D, Race, and Excessive Daytime Sleepiness — Journal of Clinical Sleep Medicine
- Vitamin D and African Americans — The Journal of Nutrition
- Vitamin D in Caucasian and African American Women — Vitamin D Council
