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Vitamin D has been in the news lately. Studies have revealed that people with lower levels of vitamin D are more likely to become seriously ill with COVID-19. Clinical trials are even underway to test vitamin D as a COVID-19 treatment. More study is needed to confirm the initial findings, but there’s still good reason to pay attention to vitamin D.

Vitamin D is already a well-established player in promoting bone health and immunity and is being studied for possible benefits in preventing and treating lots of common conditions, like cancer, heart disease and stroke, diabetes, autoimmune conditions, depression, Alzheimer’s and dementia. So how do you make sure you are getting enough of this powerful nutrient?

Between 40–70 percent of people, depending on race, are estimated to be deficient in vitamin D. Your health care provider can check your vitamin D blood level with a simple blood test. They will be looking for 20–30 nanograms/ml of 25 hydroxyvitamin D [25(OH)D]. You’ll likely get enough vitamin D if you eat 600 IU per day if you’re under 70 and 800 IU if you’re 70 or older.

If you and your doctor decide you need vitamin D, there are a few ways to get more.

Vitamin D is special, because it is the only nutrient humans synthesize themselves. Vitamin D is made in the skin as a result of exposure to sunshine. So getting outside, without sunscreen on, for short bursts can help you get the vitamin D you need without getting sunburned.

You can also aim to eat foods high in vitamin D. Fish like salmon and swordfish are vitamin D powerhouses, providing between 400 and 600 IU per 3-ounce serving. If they are too expensive, 3 ounces of ordinary canned tuna provides 154 IU, and two sardines provides 46 IU. Egg yolks include 41 IU each.

Many foods are fortified with vitamin D, including mushrooms, some of which are treated with UV light for between 124 and 1,000 IU of vitamin D per serving. Other fortified foods, including milk and some yogurt, orange juice, and breakfast cereal, provide between 80–140 IU.

While whole foods are always the best way to incorporate nutrients into your diet, you may want to talk to your doctor about a supplement, especially if you don’t eat much fish or dairy.

Vitamin D is a fat-soluble vitamin, so it can build up in the body. So you shouldn’t take too much. The upper limit is 4,000 IU a day, although some scientists feel that it could be as high as 10,000 IU daily. Given how hard it is to get, almost everyone could stand to include more vitamin D in their lives. Consider having a fortified cereal with milk and a hard-boiled egg for breakfast, taking a walk in the sunshine at midday, and making a dinner that includes tuna and mushrooms. You will be boosting your vitamin D and lending your immune system a hand to fight off any infection that comes its way.

Kristin Irace, RD, is a registered dietitian at Southwestern Vermont Medical Center.


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