Maybe you’ve heard reports that many people are now deficient in vitamin D, “the sunshine vitamin,” as we’ve tried to ward off skin cancer by staying out of the sun or wearing sunscreen. Damned if you do, damned if you don’t.
Sunlight used to be our bodies’ main source of vitamin D, its ultraviolet rays causing bare skin to manufacture vitamin D. But those same UV rays also cause skin cancer, so we’ve blocked them with sunscreen or avoided the sun. Consequently, vitamin D levels have decreased, leaving increasing numbers of people reportedly deficient in a vitamin that is essential to bone health because it helps the body absorb calcium.
After the results of recent bloodwork came in, I was told that I am deficient — a serious concern when you have a family history of osteoporosis, the fragile-bone disease. I already am in the bone-thinning stage called osteopenia, which may or may not progress to osteoporosis.
Vitamin D deficiency is also a concern for people other than those with weak bones. It has been linked not only to fractures but also heart disease, cancer, type 2 diabetes, depression, and more.
Getting enough vitamin D from food is nearly impossible; only a few foods contain much of it. Although only minimal unprotected exposure of the face or limbs to the sun — 15 minutes two to three times a week — supposedly produces adequate vitamin D, it would be hard to get that consistently when one’s facial moisturizer contains sunscreen and the rest of the body is covered most of the year in northern climates. To meet my doctor’s recommendation of 2,000 IUs a day, I’ve doubled the amount of a D3 supplement.
Vitamin D screening isn’t routine, but doctors report that requests for it increased as an “pandemic” of vitamin D deficiency was reported. I’m screened because of osteopenia. Should you ask to be screened if you never have been? It depends. As I read about vitamin D, I learned that guidance is squishy, like a lot of medical advice these days. That’s because researchers don’t agree about what blood level of vitamin D is too low.
An expert report issued by the Institute of Medicine (now the National Academy of Medicine) estimated that a level of 20 nanograms per milliliter is adequate for bone health. In contrast, the Endocrine Society said that more than twice that amount, 40–60 ng/mL, guarantees sufficiency. In a report published in the New England Journal of Medicine, a committee of epidemiologists and endocrinologists said that levels as low as 12.5 ng/mL are fine for healthy people. The National Academy of Medicine revised its guideline to 12 ng/mL. Since studies have found that only 6 percent of Americans have levels below 12.5, and 13 percent below 20 ng/ML, routine screening isn’t called for.
Furthermore, studies have found no connection between vitamin D supplements and reduced risk of heart disease, type 2 diabetes, and cancer. The jury is still out on prevention of fractures.
Consumer Reports on Health believes that most people can meet their vitamin D needs without a supplement, it said in April 2019. It advises minimal unprotected exposure to sunlight, along with eating select foods. In contrast, the American Academy of Dermatology recommends against any unprotected sun exposure and favors relying on diet and supplements.
There’s more agreement about who should be screened: populations that would be at high risk from a deficiency of vitamin D. Older people with osteopenia are among the at-risk populations. My test result was 16 ng/mL, low enough in combination with osteopenia to warrant significant supplementation.
Now I’m taking about three times the recommended daily allowance of vitamin D, which is 600–800 IUs. Even before the deficiency diagnosis, I was taking more than 1,000 IUs a day. That brings up a question to ask my doctor: If you’re getting more of a vitamin than the RDA but are still deficient, is something wrong with your body’s ability to absorb the vitamin?
FOLLOW-UP TO LAST WEEK’S TOMATO STORY
The green tomatoes that were unlikely to ripen on the balcony are turning red inside. They're on the countertop in a brown paper bag with a banana, which produce the ethylene that promotes ripening. So far I’ve had red tomatoes on salads and a sandwich. There may be enough eventually for a tomato sauce.
ANTI-TRUMP QUOTATIONS: 80TH IN AN ONGOING SERIES
“[Trump] fired an arrow at the heart of our most cherished norms and arrows. But it took the rest of us to ensure that he hit his target.”
— Catherine Rampling, Washington Post columnist