Hundreds of research studies suggest that vitamin D can help prevent everything from osteoporosis to autoimmune disorders, cardiovascular disease, and cancer.
Doctors are recommending it. Health podcasters are talking about it. Even your mom is nagging you about it.
What is vitamin D?
Vitamin D is a fat-soluble vitamin that we (mostly) get from the sun, but also from certain foods, and of course, from supplements.
What does vitamin D do?
Recent research suggests that nearly every cell of our body has receptors for vitamin D. Not surprisingly, it has wide-ranging effects on the body.
Vitamin D helps support your:
- immune system
- cell function
- blood sugar regulation
- bone health
- calcium absorption and circulation
- normal blood pressure
How do I know if I need to supplement?
For many of us, supplementing with vitamin D is a good idea. Especially if we fall into one of the categories of people who are more likely to have a vitamin D deficiency.
However, the only way to know for sure if we’re deficient is to get a blood test.
In order to optimize bone health and minimize the risk of disease, people should aim to achieve a blood level of vitamin D of at least 50 nmol/L (20 ng/mL).2 (The “sweet spot” might be closer to around 75 nmol/L, or 30 ng/mL.)
How do you get vitamin D?
The best vitamin D source, ever: The sun
Many people can meet their vitamin D requirements through sunshine alone. And as far as “natural sources of vitamin D” goes, sunlight is a tippy top choice.
A good general guideline: Get about 10-20 minutes a day of midday sun, with face, arms, hands, and legs uncovered (and no sunscreen).
The amount of vitamin D you get (and absorb) from the sun depends on a bunch of things, like geographic location, skin tone, clothing style, sunscreen use, age, and overall health.
The best vitamin D food sources
you can significantly bump up your vitamin D intake by prioritizing certain foods in your diet.
Here are some of the best sources:
The best vitamin D supplement
Vitamin D supplements can come as a pill, liquid, sublingual spray, or (yes) chewable gummy worm.
While the delivery method of the supplement isn’t so important, the form of the vitamin D in it is.
Usually, you’ll find two forms of vitamin D available in pharmacies and health food stores:
Vitamin D2, derived from yeast or mushrooms (and vegan-friendly)
Vitamin D3, typically sourced from lanolin (from sheep’s wool)
While both forms can raise blood levels of vitamin D, vitamin D3 appears to do a better job of optimizing vitamin D levels, as well as maintaining these levels longer-term.
However—and this is important—taking vitamin D when you’re not deficient will have little to no benefit—and may even cause harm.
Diseases associated with vitamin D deficiency
As you might imagine, the worse a deficiency is, the more likely negative health effects start to show up.
More extreme deficiencies of vitamin D dramatically increase the risk of premature death, infections, and many other diseases.
Some diseases associated with vitamin D deficiency:
- Osteoporosis, and general weakening or softening of the bones26
- Immune dysfunction, such as autoimmune conditions and increased susceptibility to infection
- Type 2 diabetes
- Cardiovascular disease
- Cancer, especially cancer mortality
- Obesity
- Depression
Vitamin D: Your next steps
- If possible, get some (safe) sun exposure, and aim to eat vitamin D-rich foods.
Many people’s vitamin D requirements can and should be met through sun exposure and diet alone.
Eat vitamin D-rich foods, along with a range of colorful fruits and veggies high in vitamins and minerals—like calcium, magnesium, vitamin K, and vitamin A—that support vitamin D’s work in the body.
- If you suspect a deficiency, get a blood test.
When possible, get a blood test to confirm suspected deficiencies. (That goes for other nutrients too—like iron or vitamin B12—not just vitamin D.)
And, remember that in the presence of other deficiencies, we should be careful about supplementing with high doses of vitamin D.
- Be mindful of those who are more vulnerable to deficiency.
- has malabsorption issues
- has darker skin
- lives far from the equator
- covers up (either with clothes or sunscreen)
The bottom line: Even if something is essential to our health—like vitamins, minerals, water, and, oh, let’s say, a good stash of toilet paper—more isn’t always better.
