Is Taking Vitamins Actually Good For You?

In a perfect world, we would get all the nutrients we need from food. Unfortunately, that's rarely the case. Our hectic lifestyles make it difficult to cook healthily, plan our meals, and meet our nutritional needs. On top of that, over 70% of the foods available in stores are ultra-processed, which diminishes their nutritional value, reports Northwestern University. Given these facts, it's not surprising that most Americans are "well-fed but malnourished," as the Kresser Institute puts it.

The average U.S. adult consumes about 3,600 calories per day, but more than half of these calories come from processed foods with little or no nutritional value, says the Kresser Institute. Millions of Americans are deficient in iron, folate, vitamin A, and other micronutrients. The Linus Pauling Institute estimates that nearly 50% of the population fails to get enough calcium from food; a whopping 97% of Americans don't meet the recommended daily potassium requirements; and 61% are deficient in magnesium.

While it makes sense to take a daily multivitamin to prevent nutrient deficiencies, some experts say that supplements are a waste of money. So what are the potential benefits and pitfalls of taking vitamins?

About half of American adults take vitamin supplements, according to Johns Hopkins Medicine. Yet, clinical research doesn't support the claims behind these products. As it turns out, multivitamins and other supplements are unlikely to protect against cancer, cardiovascular problems, or cognitive decline. Moreover, some can be detrimental to human health when consumed in excess.

In clinical trials, alpha-tocopherol and beta-carotene failed to reduce lung cancer risk in male smokers. These supplements actually increased the odds of stroke and lung cancer, according to a 2012 review published in the International Journal of Preventive Medicine. Other dietary supplements, including vitamins C, D, E, and calcium, didn't lower the risk of heart disease, colorectal cancer, or premature death. Some had the opposite effect, leading to a higher risk of cardiovascular events, prostate cancer, and other ailments. For example, subjects who took vitamin E for longer than five years had 17% higher odds of developing prostate cancer, notes the review.

However, vitamin supplements are unlikely to affect your health in the short run, explain the researchers. Additionally, pregnant women and other groups at risk for nutrient deficiencies may need dietary supplements. Apart from that, most people should be able to obtain the necessary nutrients from food. "Pills are not a shortcut to better health and the prevention of chronic diseases," says internal medicine specialist Larry Appel (via Johns Hopkins Medicine). He also points out that healthy eating and weight management are more beneficial than any pill. 

There are instances where it makes sense to take vitamin supplements. These products may benefit pregnant women and those trying to conceive, as well as older adults or people who've had bariatric surgery, explains the Mayo Clinic. You may also need to take multivitamins and other supplements if you have food allergies, inflammatory bowel disease, or other conditions that affect nutrient absorption.

Consider your lifestyle, too. For example, individuals who spend a lot of time indoors or live in cold climates may need vitamin D supplements, dietician Anne Linge told the University of Washington. The human body produces this nutrition when exposed to sunlight. If you live in a cold area, your body may not synthesize vitamin D properly. Another nutrient you might not be getting enough of is vitamin B12, which occurs mostly in animal foods. Therefore, vegans and vegetarians may need supplements to make up for what they aren't getting in their diets. The same goes for those taking Metformin, a diabetes drug, and other medications that deplete vitamin B12 levels, says Linge.

If you're at risk for osteoporosis, consider taking calcium and vitamin D supplements. Both nutrients are essential for bone health and may help prevent osteoporotic fractures, according to 2018 research published in Therapeutics and Clinical Risk Management. Note, though—calcium supplements can interfere with certain antibiotics and other drugs and may increase the risk of kidney stones. Likewise, excess vitamin D may cause stomach pain, muscle aches, and kidney problems, warns the Cleveland Clinic.