What's the Deal with Vitamin D?

Learn the latest about this controversial must-have vitamin.

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There’s a lot of confusion out there about vitamin D. It’s a nutrient and a hormone; we can get it from a pill, from food, from the sun. And there are different types! So what do we do, and how much do we do it? And the question burning in everyone’s mind: do I really have to drink a cup of milk every day?

Vitamin D

Vitamin D is a group of fat-soluble vitamins that help the body absorb and retain calcium and phosphorus, both of which are critical for bone health. In experimental studies of cancer cells and of tumors in rodents, vitamin D has been found to have several biological activities that might slow or prevent the development of cancer. It’s been shown in studies to help control infections and modulate the inflammatory/immune system. There is mounting evidence that higher vitamin D blood levels are associated with lower rates of Type 2 diabetes. Some studies have found links between low blood levels of vitamin D and an increased risk of depression. 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. So, yeah, it’s important.

And we’re not getting enough! According to the National Institute of Health, the Recommended Dietary Allowance (RDA) for adults 19 years and older is 600 IU (15 mcg) daily for men and women, and for adults over 70 years, it is 800 IU (20 mcg) daily. The Tolerable Upper Intake Level (UL) 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 (100 mcg).

The CDC’s National Health and Nutrition Examination Survey found that the median intake of vitamin D from food and supplements combined in women ages 51 to 71 years was 308 IU daily, but only 140 IU from food alone (including fortified products). 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.

So what’s the plan?

A Vitamin D Rich Diet

We subscribe to the notion that nutrients are best received through food, but very few foods naturally contain vitamin D. The best natural sources are fatty fish like trout, salmon, tuna, mackerel and fish liver oil. Beef liver, egg yolks and cheese also have small amounts of vitamin D. Most Americans get the majority of their dietary vitamin D from fortified foods, like—you guessed it—milk. Almost all of the U.S. milk supply is fortified with about 3 mcg (120 IU) vitamin D per cup. Milk consumption in the U.S. has been on a steep decline for years, however, as people lean more toward plant-based alternatives like soy milk, almond milk, and oat milk. But good news: many of those are similarly fortified. It’s also added to many breakfast cereals, some orange juices, some yogurts, and other food products.

Mr. Sun, Mr. Golden Sun

Your body makes vitamin D when your bare skin is exposed to the sun’s ultraviolet-B (UVB) rays. (Vitamin D2 is produced in plants and fungi; Vitamin D3 is produced in animals, like us.) Most of us get some vitamin D this way.

According to the National Institutes of Health, the general recommendation is that exposing your face, arms and legs to sunlight for 5 to 30 minutes, two to three times per week is sufficient to produce adequate amounts of vitamin D, but this greatly varies depending on weather, season, location, and more. Not to mention, what else can we get from UVB rays? Yup, skin cancer. The same things that protect against damaging UVB rays like sunscreen and pigment (melanin) also block the production of vitamin D, along with clouds, smog and old age.

This feels like the ideal time to employ one of my favorite sayings: damned if you do, damned if you don’t. Time to consider supplementation.

Supplements

Sometimes we all need a little help. Luckily, the cup of vitamin D supplements runneth over. The two forms of vitamin D in supplements are D2 (ergocalciferol) and D3 (cholecalciferol). Vitamin D2 is made from plants and is found in fortified foods; Vitamin D3 is naturally produced in the human body and is found in animal foods. Both forms increase vitamin D in your blood, but D3 might raise it higher and for longer than D2. You can find it in a solo supplement, or combined with other vitamins, liquid or pill form. Find what works for you!

Read more in the top trending articles about vitamin D:

This article from Insider discusses how muscle cramps and back pain were the result of a vitamin D deficiency.

In a 2022 study of more than 427,000 White European participants using Mendelian randomization, a 54% higher risk of dementia was seen among participants with low vitamin D blood levels of <25 nmol/L compared with those having adequate levels of 50 nmol/L.

In this report from Scientific Reports says that hip fractures were less likely to occur in individuals who were prescribed vitamin D.

This Science Direct report outlines the administration of vitamin D3 supplements demonstrated a potential reduction in the occurrence of atrial fibrillation in both men and women with overall good health.

Until next week, go get some sunshine and continue to Age and Prosper!