SCIENCE
10 THINGS YOU NEED TO KNOW ABOUT VITAMINS
No doubt you’ve heard claims that they boost energy, save your memory, and prevent serious disease. But there is no one-pill-helps-all solution, and good research is in short supply. Here’s what you should know to make smart decisions.
BY KAREN ROBOCK
1 Nutritious meals beat a pill or a powder pretty much every time.
“People forget they are supposed to supplement food, not replace it,” says Monica Auslander Moreno, R.D.N., lead dietitian of Essence Nutrition in Miami. Vitamin supplements are useful to enhance the benefits of a well-balanced diet loaded with nutritious vegetables, fruits, whole grains, and proteins—not to offset too many drive-through trips. But despite the food-first mantra nutrition experts preach, more than half of Americans rely on supplements to try to meet their needs, and we spend close to $50 billion a year on them. “People think it’s easier to pop a pill than to actually address a nutrition knowledge gap or an intake shortfall,” says Auslander Moreno.
2 Multivitamins might—might!—protect you from dementia and cognitive decline.
Research on the effcacy of brain-boosting, memory-aiding supplements has been mixed, and in 2019 the Global Council on Brain Health published a report questioning so-called memory supplements, a multibillion-dollar business that targets the aging population. But the findings of a new study published in Alzheimer’s and Dementia showed that supplements could play a role in improving cognition and possibly slow brain aging. Researchers, who were looking at whether taking daily cocoa extract or a multivitamin for three years could benefit cognition, expected to see benefits from regular use of cocoa extract, but they instead found that multivitamins measurably improved memory and executive function in older adults.
“Our findings opened up a new avenue for investigation to identify a potentially simple and highly accessible strategy to protect against cognitive decline,” says Laura D. Baker, Ph.D., one of the study’s lead investigators and a professor of gerontology and geriatric medicine at Wake Forest University School of Medicine in North Carolina. Nothing is definitive, but, says Baker, “we are planning a larger study, with even more participant diversity, to confirm our initial findings and better understand why multivitamins might offer protection against cognitive decline.”
3 There are folks who very likely need certain supplements.
People on restricted diets, as well as those facing food insecurity or with certain gastric disorders that inhibit nutrient absorption, might not be having all their nutritional needs met. Auslander Moreno recommends a B vitamin complex and iron as well as an omega-3 supplement to some of her vegan clients. People with anemia or inflammatory bowel disease as well as pregnant and lactating women often need some degree of supplementation too, she says, and folks who have had gastric bypass or live with Crohn’s disease may also be deficient. People over 50 may need a boost of specific micronutrients in their diets, as we tend to absorb some nutrients, like B vitamins, less well as we age. Auslander Moreno recommends supplements not to all her clients, but “only to those for whom intake of a nutrient is or risks being suboptimal,” she explains.
4 Multivitamins are not proven to reduce the risk of cancer or heart disease.
According to the latest report from the U.S. Preventive ServicesTask Force (USPSTF), there is insufficient evidence that your daily multi is protecting you from these two major diseases. When the task force examined the effects of vitamins A, B3, B6, B12, C, D, and E as well as multivitamins, calcium, and several other nutrients, it found little or no benefit to popping a daily pill in preventing any form of cancer or heart disease (the leading causes of death in the United States). “I and my colleagues have been following the literature around supplements, and there remains no convincing evidence that for otherwise healthy adults who have a healthful diet, supplements offer much in the way of benefits,” says Jeffrey Linder, M.D., chief of general internal medicine in the department of medicine at Northwestern University Feinberg School of Medicine in Chicago and coauthor of an editorial published in JAMA. In fact, says Dr. Linder, relying on multis may breed complacency: “Multivitamins and supplements are probably distracting people from things that will help them live longer, like eating a healthful diet, getting exercise, being a healthy weight, and avoiding smoking.” That said, if you are not eating well or are at risk of deficiencies because of a health condition, you should talk to your doctor and follow their advice on whether supplementing makes sense for you.
5 Not all vitamin supplementsare created equal.
The supplement industry is not regulated like the pharmaceutical industry is. “The FDA, sadly, is underequipped to regulate supplements,” says Auslander Moreno. And manufacturers aren’t required to gain approval or meet specific FDA safety or efficacy standards before products hit store shelves. “I would prefer if we had a system where supplements were subject to rigorous regulation and maintenance auditing to keep people safe and informed,” Auslander Moreno says. For now, your best bet is to look for recognized third-party testing certifications that can verify the quality of what you’re buying. NSF and USP, for example, ensure that a supplement contains what it says it does and that it doesn’t have unacceptable levels of impurities.
6 You should talk to your doctor before you start taking a supplement.
They can help you determine which, if any, vitamins you might need and whether there are any potential interactions with medicines you are taking. Some supplements can change the metabolism, absorption, or excretion of prescription or over-the-counter drugs, and this can affect how well a medication works. If you’re taking a blood thinner, for example, you should avoid supplementing with vitamin E, as it also has a blood-thinning effect. And someone taking a B12 supplement who is then given metformin for type 2 diabetes may require a bigger dose of B12 than before. That’s why taking a DIY approach to supplementing isn’t a great idea.
7 A daily dose of vitamin D doesn’t guarantee healthy bones.
The first large randomized controlled study in the U.S. found that vitamin D pills, taken with or without calcium, had no effect on bone fracture rates. (People who have osteoporosis or low bone mass may still require a supplement.) Some still argue that vitamin D supplements help with immune function and reduce inflammation, but it’s more complicated than that, according to findings from the recent Vitamin D and Omega-3 Trial (VITAL) study. “Low vitamin D levels are associated with almost everything from colon cancer to cardiovascular disease and other conditions,” says Dr. Linder. “However, there’s no evidence that supplementing with vitamin D prevents any of these things from happening.” Unfortunately, this is another ask-your-doctor situation.
8 If you hope to get pregnant, take a multi.
This is advisable because it contains folic acid, a B vitamin important for metabolism and cell growth. Most people get enough—many foods (including breads, pastas, and breakfast cereals) are enriched with folic acid, and folate is found naturally in a number of fruits, vegetables, and legumes including leafy green vegetables, oranges, and beans. But folic acid is so effective at preventing some major birth defects when moms-to-be supplement with it before and during early pregnancy that the Centers for Disease Control and Prevention recommends that all women of reproductive age take 400 micrograms of folic acid and that pregnant women also get 400 micrograms.
9 Certain vitamins can be bad for your health.
Some have the potential to do more harm than good, especially at higher doses. One serious example is that people who have cancer should not take vitamin C during chemotherapy, as it may reduce the effectiveness of treatment. The USPSTF guidelines caution against beta-carotene, since it has been found to increase the chances of cardiovascular death and lung cancer, particularly in people who smoke. They also raise a red flag about vitamin A: “In excess, vitamin A is associated with decreased bone density, hip fractures, and liver problems,” explains Dr. Linder. Pets and kids should be kept away from vitamins not intended for them.
10 There’s a lot we just don’t know.
“We should be investing a lot more in nutrition research,” says Taylor C. Wallace, Ph.D., a nutrition scientist and an affiliate professor in the department of nutrition and food studies at George Mason University in Virginia. “We already know that what we feed our bodies has a great deal to do with our short-term wellness and long-term health, but all things considered, there’s not a lot of research being done to understand exactly which nutrients we need and in what quantities,” he says. Only about 5% of the National Institutes of Health’s annual budget is allocated to nutrition research. That’s why Wallace sees a daily multivitamin as a low-risk way to protect yourself against possible hidden micronutrient deficiencies. “A multivitamin is like a bit of added insurance,” he says. ■