As a supplement, vitamin D has been a common staple on drugstore shelves for years — and its popularity is only growing.
In the United States, its market value is expected to reach $1.3 billion by 2025. Studies show a sharp rise in vitamin D deficiency diagnoses over the past two decades, and the over-the-counter supplement claims to boost vitamin D deficiency. health of your bones, muscle function and immune system.
The supplement took on new life last year when people started taking vitamin D pills as a preventive measure against Covid. Today, medical experts generally agree: vitamin D does not prevent contracting the virus. And while scientists are still trying to determine if it can reduce the severity of infections, due to its immune-boosting benefits, it certainly does not replace vaccination.
But Covid concerns aside, doctors have mixed opinions of the supplement. Some say that when taken in moderation, it’s a harmless daily pill that can only help most Americans. Others argue that it’s a largely unnecessary expense – and that in most cases it’s even irresponsible to test patients for vitamin D deficiencies.
“It’s a really tricky subject. There really isn’t any consensus literature. There aren’t any good large-scale studies on vitamin D without any conflict of interest,” Dr. Neha Vyas, family physician at the Cleveland Clinic. “You really have to be careful.”
If You Feel Healthy, You Probably Don’t Need Supplements
“You really don’t need to screen people with vitamin D deficiency who are low risk or asymptomatic,” says Dr. Kendall Moseley, medical director of the Johns Hopkins Metabolic Bone & Osteoporosis Center. “One of the reasons there’s been an ‘increased prevalence’ of vitamin D deficiency over the past five to 10 years isn’t really because we’re all becoming vitamin D deficient. We’re just looking for more now.”
A landmark study published last month in the New England Journal of Medicine confirms Moseley’s position. Researchers studied 25,871 participants – men aged 50 and older and women aged 55 and older – and found that vitamin D supplements had no tangible effect on the health of “middle-aged adults. and older generally in good health”.
If you break bones during simple activities, feel bone pain when touched, or have enough muscle pain or weakness to prevent you from being able to get up comfortably from your chairs, you should consult your doctor about possible vitamin D deficiency, says Moseley. . Generalized fatigue and low mood can also be correlated with deficiencies, she adds – and you may be particularly at risk if you have darker skin or spend your winters in places at high latitudes.
Moseley points out that if you have any of these symptoms, over-the-counter supplements are not recommended because if you have a severe deficiency, the specific dose you need to take is important.
But Vyas says you shouldn’t be surprised if your doctor sees vitamin D as an immediate culprit: Many symptoms associated with vitamin D deficiencies are also often associated with other, more serious health conditions.
“As scientists, we have to be very careful how we approach our patients,” says Vyas. “We don’t want to say, ‘Oh, you’re tired’ or ‘Oh, you’re depressed, let me check your vitamin D’, because there are so many [potential] reasons for that.”
The Dangers of Vitamin D Toxicity
If your doctor doesn’t think you’re particularly at risk for severe vitamin D deficiency, or thinks your symptoms don’t warrant screening, your path forward essentially comes down to risk versus reward.
Mild deficiencies are actually “pretty common” because most people don’t get enough sunlight in their daily lives to absorb a healthy amount of the vitamin, says Dr. Jad Sfeir, an endocrinologist at the Mayo Clinic. They go largely unnoticed, he says: Most people could live their whole lives with a mild impairment and never know it.
Yet even mild deficiencies can have eventual consequences. “Ultimately, this puts you at risk of making your bones quite fragile and prone to fractures,” says Sfeir. “It can go for years, completely unnoticed, until we detect osteoporosis by looking at a bone density scan – in women, usually after menopause, and in men, usually after age 60. or 70 years.”
Sfeir says you can safely fix the problem early by ingesting about 600 to 800 international units (IU) of vitamin D daily. If you can get this entirely from your diet, you may never need supplements, he says. So consider tracking how much vitamin D you get from sources like fortified milk and orange juice, or fatty fish like salmon or mackerel.
Just be careful when adding over-the-counter supplements to the mix. Exceeding a total of 4,000 IUs per day exposes you to a dangerous level of toxicity, by overdosing the amount of calcium in your bloodstream and urine, Sfeir says. This can lead to symptoms such as kidney stones, nausea, vomiting, cognitive changes, memory impairment and even kidney failure, Moseley adds.
Currently, if you search for “vitamin D” on Amazon, you’ll see a plethora of potentially dangerous high-dose options – from 2,000 IU to 5,000 IU per tablet – before you get to anything below the figure of 600 IU of Sfeir. Moseley also notes that vitamin D can exist in other supplements you’re already taking, from beauty supplements to energy pills.
In a high-profile example, published last month in the medical journal BMJ Case Reports, a Briton was hospitalized for eight days, just a month after starting a regimen of 150,000 IU vitamin D a day.
“It can take a year — or longer, sometimes — for things to normalize. In really extreme cases, patients need to go on dialysis,” says Moseley. “It is much more difficult to repair an excess of vitamin D than to repair a lack of vitamin D.”
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