Vitamin Spotlight: Vitamin D

There are a number of vitamins and minerals that are essential for your body to stay healthy. One of them is vitamin D. Here, we’re looking at the essentials of this vitamin, including its benefits and purpose.

What is Vitamin D?

Like vitamin A, vitamin D is a fat-soluble vitamin. It’s present in very few foods naturally, is added to others, and can be taken as a dietary supplement. However, Vitamin D is unique from most other vitamins because your body can make its own vitamin D when you expose your skin to sunlight. The vitamin is produced endogenously when UV rays from the sun hit the skin and trigger synthesis of vitamin D.

Regardless of how vitamin D is obtained, it is biologically inert, so it must go through two hydroxylations (a chemical process) in the body for it to activate. The first hydroxylation occurs in the liver, where vitamin D is converted to calcidiol. The second hydroxylation happens in the kidney and forms calcitriol.

What Does Vitamin D Do for the Body?

Vitamin D is important for a number of reasons, but it’s best known for its contribution to building strong bones. Calcium and phosphorus are necessary to develop the structure and strength of your bones, but vitamin D is required for your body to absorb these minerals. So even if you get a lot of calcium and phosphorus, your body can’t absorb them if you don’t get enough vitamin D.

Beyond building strong bones and teeth, research in the past few years has shed more light on the functions that vitamin D helps with, including:

  • A strong immune system. Vitamin D can help boost your immune system, thereby helping you fight infection.
  • A healthy cardiovascular system. Vitamin D can help you maintain a healthy heart and circulation.
  • Strong muscle function. Vitamin D is important to musculoskeletal health, helping your muscles perform well.
  • A strong respiratory system. Vitamin D helps your body maintain healthy lungs and airways.
  • Diabetes management. Vitamin D helps regulate your insulin levels.
  • Disease prevention. Vitamin D may help protect against a number of conditions, including types of cancer, multiple sclerosis, and diabetes.

What Foods Contain Vitamin D?

As explained earlier, not many foods naturally contain vitamin D. Fish oil and fatty fish are the best food sources of vitamin D. Among fatty fish, reach for salmon, tuna, and mackerel for the best source. There are small amounts of vitamin D in several other foods, including beef liver, cheese, egg yolks and mushrooms. Most people get vitamin D from fortified foods, where vitamin D has been added, such as milk and other dairy products.

Despite vitamin D being present in these foods, sun exposure can be the most efficient way for getting enough vitamin D. By some estimates, just five to ten minutes of sun exposure on bare skin two to three times per week can be enough to produce sufficient vitamin D. Just remember, vitamin D breaks down quickly, so it’s easy to run low on the vitamin, especially in the winter.

What are the Side Effects of Vitamin D Deficiency?

There are a few common side effects of a deficiency. You may find yourself getting sick more often, feeling frequently fatigued or weak, experiencing depression, having bone pain and experiencing impaired wound healing.

Ongoing vitamin D deficiency can further negatively impact your health, resulting in obesity, diabetes, hypertension, chronic fatigue syndrome or osteoporosis.

 How Can I Tell if I’m Deficient in Vitamin D?

Vitamin D deficiency is common, and some people are more susceptible to it than others. Having darker skin, not eating much fish or milk, living far from the equator or staying indoors can put you more at risk for vitamin D deficiency.

If you don’t eat fish or milk and don’t get much sunlight without sunscreen, you may want to take a vitamin D supplement to prevent a deficiency. But remember that there is such a thing as too much vitamin D. Excess amounts can result in nausea, vomiting, weakness, heart rhythm problems and kidney damage.

While everyone’s dietary needs are different, the general recommended dietary allowance for vitamin D among adults is 1,000 mg per day. And as we shared, vitamin D deficiency is fairly common, as it’s much more difficult to get enough of this vitamin, as opposed to other vitamins that are prominent in a number of foods.

Concerned you may not be getting enough vitamin D? Consider taking a DNA test, such as PathwayFit, which looks at which vitamins you may need to optimize. With the guidance of your physician, you can determine an effective diet for you.