12 Vitamin Mistakes You Might Not Realize You’re Making

Updated: Apr. 08, 2021

Vitamins and supplements, which some 50 percent of Americans take regularly, might optimize your health—if you're smart about how you use them. Here's what to know about popping those pills safely.


You pop a multivitamin

Unless your doctor recommends one for a specific reason, this daily habit may be worth skipping. “For the most part, multivitamins are a poor investment, says Les Emhof, MD, an MDVIP-affiliated physician in Tallahassee, Florida. “They just give you expensive urine.” In an editorial published in the Annals of Internal Medicine in 2013, Johns Hopkins University researchers concluded that popping a multi does not lower disease or mortality risk. Experts agree that your best bet is to get vitamins and minerals from whole foods. Don’t miss these other 8 vitamins that are useless or even dangerous.


You’re take a random assortment

Every body is different, so choosing vitamins and supplements willy nilly—or trying brands your friends have recommended—isn’t necessarily what’s best for your individual needs. Dr. Emhof gives his patients a blood test to suss out common deficiencies such as vitamin D and B12, and then doles out recommendations based on the results. For other issues, your doctor may suggest supplements based on medical history. For example, if you are grappling with nighttime leg cramps, you might have a magnesium deficiency (here are more signs you’re low in magnesium)—not a potassium deficiency, he says. Find out how to spot other signs you need more potassium.


You live in a sunny climate, so you skip vitamin D

If you’re living in the northern part of the country during a snowy winter, you’re probably short on vitamin D—but it’s also likely true for people living in the sunny south, says Dr. Emhof. “I live in Florida, and 90 percent of my patients are vitamin D deficient,” he says. (Here’s how to know if you need more vitamin D.) While the Institute of Medicine recommends that adults 70 and younger need 600 international units (IUs) of vitamin D per day, Dr. Emhof says some people may need at least 5,000 IU. “You need a blood test to determine the right amount for you,” he advises. Before you head to the pharmacy, here’s what you need to know before taking vitamin D supplements.


You assume you need calcium supplemnents

This mineral, along with vitamin D, is key for skeletal strength, but too much calcium might be a bad thing. Research in the Journal of the American Heart Association recently showed that taking a calcium supplement was associated with 22 percent higher odds of atherosclerosis, or clogged arteries. (Check out the silent signs you could have clogged arteries.) Eating calcium-rich foods, on the other hand, was found to be protective for your ticker—so continue to bone up on yogurt, cottage cheese, and leafy greens. Don’t miss these other 8 vitamins women should stop wasting money on.


Your probiotic is weak

We’re all into boosting gut health these days, so if you’re taking a probiotic, make sure it has enough going for it to make it worthwhile. (Here are signs you should be taking a probiotic.) “So many supplements don’t have enough varying strains of bacteria, and that won’t do anything for you,” says Dr. Emhof. He tells his patients to look for one with 10 strains, like the Ultimate 10 Probiotic. Another good option is Just Thrive Probiotic, 100 percent of which has been shown to survive the harrowing journey to the small intestine through stomach acid, where many other probiotics are killed off. You could also stock your grocery cart with these 7 probiotic-rich foods for gut health.


You’re overdosing

If some is good…more must be better, right? Not so much. Popping megadoses of vitamins, particularly vitamin E and vitamin A, hasn’t been shown to protect against heart disease, and may even raise your risk of dying, points out the National Institutes of Health. Plus, these supplements could actually increase your risk of cancer. Which vitamins should you take? Steal the supplement secrets doctors tell their friends.

iStock/Roel Smart

You ignore your meds

Look at the array of supplements you pop daily—are they all compatible with your medications? While it’s easy to assume that “natural” supplements and herbs are harmless, they can interact with certain prescriptions and have dangerous consequences. In fact, one in six older adults are taking a potentially harmful combination of drugs and supplements, reports a 2016 study from the University of Illinois at Chicago. The lesson: Be open with your doctor about everything you’re taking—even if it seems benign. And be aware that there are also potential downsides to certain drug and food combinations.


You take iron too often

Iron supplements are so important to treat symptoms of anemia, but getting the dosage right can be tough. (Not to mention, side effects such as nausea often accompany them, making the mineral hard to stick with.) A new study in the journal Blood suggests that waiting longer intervals between taking each dose may help improve absorption. (Don’t miss these other 14 simple ways to make vitamins more effective.) The research is still preliminary, but if you’ve been wrestling with GI complaints after popping your iron pills or not seeing improvement in levels, this may be one strategy to ask your doc about. You could also try loading up on these 11 high-iron foods for vegetarians.


You’re don’t take iron strategically

Speaking of iron, if you’re donating blood, you may want to pop a supplement afterward, suggests a 2015 National Institutes of Health study. Doing so helps cut the time it takes for your blood to recover its iron and hemoglobin counts by more than half, and can possibly help you avoid iron-deficiency anemia, a common side effect of regular blood donation. This is how you should be storing your vitamins and supplements at home.


You take a turmeric supplement

Have you heard about the disease-busting, anti-inflammatory power of turmeric? It’s one of the most buzzed-about ingredients today because it’s rife with the powerful antioxidant pigment curcumin, which may offer protection against dementia, among other benefits. (Find out if turmeric really lives up to its hype.) However, a curcumin supplement is best taken with food for proper absorption, notes Dr. Emhof. Though there’s nothing wrong with a supplement, you’re better off sprinkling turmeric on your food at meal times. Add the yellow spice to rice dishes, casseroles, slow cooker recipes, and even smoothies.


You don’t scrutinize the ingredients list

Don’t assume that what’s on the label is actually what’s in the bottle. At least that’s the takeaway from the New York State attorney general’s office last year when they revealed the results of tests on major supplement brands. Their labs discovered that 80 percent of herbal supplement labels were misleading, as reported in the New York Times. (Don’t miss these other 8 secrets vitamin manufacturers don’t want you to know.) A good place to look for quality supplements is on the Consumer Lab website. Read these 11 ways you read nutrition labels wrong before taking a peek.


You assume your doctor knows a lot about supplements

Vitamins and supplements may be a nearly $28 billion dollar industry, but that doesn’t mean all doctors are up to speed. “Unfortunately, medical schools traditionally don’t teach nutrition,” Dr. Emhof says. So while you want to ask your doctor questions about the supplements you should take (and are taking), know in advance that he or she may not have all the answers. Your doctor can order a blood test, however, which will highlight any shortfalls in your diet that might suggest a need for supplementation. Check out these 10 symptoms that you’re low on key vitamins.