What You Need to Know About Vitamin D

Known as the sunshine vitamin, vitamin D is probably the most talked-about of the micronutrients. If you haven’t previously supplemented it, now might be a good time to consider it as we spend more time at home to avoid COVID-19. Public Health of England went as far as recommending a vitamin D supplement.

Let us start by saying there is no evidence that vitamin D reduces risk of COVID-19. But, vitamin D does help prevent viruses from replicating in the body. It helps the immune system resist bacteria and viruses. In some studies, higher levels of vitamin D showed to help reduce risk of flu, but more research is needed.

In addition, vitamin D is  associated with good bone health. It regulates the levels of calcium and phosphorus in the blood. It is also essential to thyroid functioning and can prevent cells from becoming cancerous. The body also needs vitamin D in order to absorb calcium.

So, make sure you’re getting your daily dose.

How to Get Vitamin D

The recommended daily intake for children and adults up to age 70 is 600 IU. Adults over 70 should increase their dose to 800 IU. Of course, if you have any health concerns or conditions, talk to your doctor before taking dietary supplements.

It’s not easy to get in the diet because most of us don’t eat vitamin D-rich foods like cod liver oil, beef liver, swordfish and sardines.  More common food sources are tuna, salmon, egg yolks, and shitake mushrooms. It’s also fortified in milk, yogurt, juices, breads, and breakfast cereals.

Another source of vitamin D is sunshine. It’s not quite as simple as going for a walk on a clear day though. Vitamin D isn’t just absorbed. The body gets to work making it when direct sunlight (not through glass) hits the skin. The process can take several hours or even days as the compound gets activated in the liver and kidneys.

A fair-skinned person wearing a bathing suit needs about 5 to 15 minutes of midday sun exposure a few times a week to get the recommended doses. Someone with very dark skin will need 50 to 150 minutes in the sun. However, again, it’s not so simple. Absorption can be impacted by cloud cover, air pollution, sunscreen, latitude, altitude, and your age. It’s generally assumed that most people do not get adequate vitamin D from the sun and in fact, sunbathing is not generally recommended for skin health reasons.


The body only absorbs about half of the vitamin D ingested, but there are a few tricks for getting more. As a fat-soluble vitamin, vitamin D needs fat in your diet to bind to. So take it at the same time as you eat some fat, like full-fat dairy, olive oil, or nuts. Taking a smaller dose two or three times a day with a meal can also help increase absorption.

Getting too much vitamin D can lead to a build up of calcium in the blood, which can cause kidney stones. Do not exceed 2,000 IU per day without talking to your dietitian or doctor. A common cause of vitamin D toxicity is taking both a multivitamin and vitamin D supplement.

Image by Helin Loik-Tomson

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Candace Nelson

In the mountains or water debate, Candace Nelson, MS, CN chooses water every time. She is a licensed nutritionist and loves taking any fitness class that makes her forget she's working out. Read more at candacenelson.net

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