That means if your meals are rich in lean proteins, whole grains, fruits, and vegetables, your supply of vitamins A, C, K, potassium, calcium, and so on, shouldn’t really be a huge concern. For example, most adult men only need 120 micrograms (mcg) of vitamin K per day, according to the National Institutes of Health (NIH). You can get that from just one cup of raw spinach, while many vitamin K supplements only offer 100 mcg per tablet.
What’s more, consistently overdoing it on certain vitamins may actually do you more harm than good, says Wirtz, specifically fat-soluble ones like vitamins A, D, E, and K.
“We’ve seen individuals with acute liver failure due to mega doses of vitamin and mineral supplements,” she explains.
Mega doses refer to supplements that contain more than 100 percent of the daily value listed on the label, she explains. For instance, vitamin A can be toxic if you consume high amounts of it over an extended period of time, according to the NIH. Your body can only absorb fat-soluble vitamins when you pair them with oils and fats in your diet, so excess amounts are primarily stored in your liver, causing it to build up in your body. This chronic build up lead to hypervitaminosis A, which is rare, but can cause dizziness, nausea, headaches, skin irritation, or joint and bone pain.
“Sometime I think the health halo effects surrounding these nutritional supplements can lead people astray and cause them to be less cautious when they’re consuming something like that,” says Wirtz.
Water soluble vitamins, like B vitamins, tend to be less risky because, assuming you have healthy kidneys, your body will be able to flush them out, she adds. (That doesn’t mean they don’t come with their own health concerns. Taking high doses of vitamins B6 and B12 has been associated with lung cancer in men.)
When Do You Need to Worry About Your Vitamin Deficiency Risk?
While your nutrient-dense diet of whole foods probably has you covered, some people are a greater risk for deficiencies than others, says Wirtz.
Vegans and vegetarians, for example, may have a hard time getting enough vitamin B12 and iron, because those nutrients are typically found in meat, she says. In addition, vegans may have a hard time getting enough calcium, vitamin D, and omega-3 fatty acids, according to a review published in the Journal of the American Osteopathic Association.
And for those with celiac disease, going gluten-free means you might fall short on vitamin D, B12, and calcium, according to a review published in Clinical Nutrition. That’s because you may need to cut out wheat-based foods that are often fortified with those nutrients, says Wirtz. It’s not that these diets are totally unhealthy, but they require some planning to ensure that you’re giving your body what it needs, she explains.
That said, there are some vitamin deficiencies you hear about all the time, like vitamin D. One oft-cited study published in Nutrition Research found that 43 percent of U.S. were deficient in D. The problem is, the current recommendations for vitamin D just aren’t agreed on right now, says Wirtz.
“Many experts say that most adults should be getting at least 800 to 1,000 international units (IU) of vitamin D per day, while some are advising upwards of 2,000 IUs a day,” she explains. But depending on where you live—think Midwest in January—getting enough sun can be a struggle. Plus, while some foods do contain vitamin D, like fatty fish and fortified milk, it can be difficult to get enough through food sources alone. For this reason, if you think you might be at risk for vitamin D deficiency, a supplement might be actually be beneficial.
Your move, then, is to check in with your doc before you start popping any pills. If you suspect you’re not getting enough of a certain vitamin or mineral, he or she can run tests to rule out any other health problems that might be causing weird symptoms. Then your doc can help you figure out your next move once you’re tested.
7 Foods Doctors Prescribe:
If you’re truly curious about which nutrients to keep on your radar, check out this quick cheat sheet on three supplements that can be helpful—and three that are just wasting your money.