Multivitamins are the most widely used nutritional supplement in the United States. But despite their popularity, there is a lot of debate as to whether multivitamin supplements are necessary.
While some diseases and health conditions can be caused by nutrient deficiencies, in the developed world, where there is a wide availability of nutrient-dense foods, some question how common true nutrient deficiencies are. And yet, the majority of Americans fall short of the recommended fruit and vegetable intake. Read on to hear what registered dietitians have to say about supplementation with multivitamins.
What Are Multivitamins?
Vitamins are nutrients that the body needs to maintain normal cell function, growth, and development. Typically, multivitamins are used when someone’s not able to get enough of these nutrients from their diet. There also are multivitamin-mineral supplements that provide minerals as well as vitamins.
An analysis of dietary supplement use in the United States from the 2017–2018 National Health and Nutrition Examination Survey (NHANES) found that multivitamin-mineral supplements were the most commonly consumed supplement among adult men and women, with 24% of adults ages 20 to 39 taking them regularly. For people ages 40 to 59, usage increased to 29.8% and grew to 39.4% for people ages 60 and older.
Who Needs a Multivitamin?
Despite their popularity, not everyone needs a multivitamin — but a few groups may benefit. Here’s a look at who falls into these groups.
Those Following Restrictive Diets
Multivitamins can be a nutritional tool to help bridge the gap for those who are following patterns of eating that restrict or omit food groups, such as vegans and vegetarians, says nutrition expert Maya Feller, MS, RD, CDN, the author of Eating from Our Roots: 80+ Healthy Home-Cooked Favorites from Cultures Around the World.
Keep in mind that if you have one or two dietary gaps to cover, you may not need a multivitamin. For example, if you follow a vegan diet but eat a wide variety of foods, you may just need to supplement nutrients that are generally not present in large amounts in plant foods, such as vitamin B-12, vitamin D, omega-3 fatty acids, and possibly calcium and iron, Feller says.
Or if you have iron deficiency anemia, your healthcare provider will likely recommend an iron supplement to help you get to a healthy range and then assess whether or not to continue that supplement, depending on what’s causing the anemia.
Those Who Are Pregnant or Trying to Conceive
Feller also notes that people who are pregnant or trying to conceive can also benefit from a multivitamin — specifically, a prenatal.
Similar to multivitamins, prenatal vitamins are meant to fill the gap in nutrients you may be missing or need to boost while pregnant so your body can grow a healthy baby. For example, folate or folic acid is particularly important before and during pregnancy, as it helps prevent major birth defects of the fetus’s brain and spine, according to the American College of Gynecology (ACOG).
Those With G.I Disorders
Multivitamins may be beneficial for people living with G.I. disorders that can cause excessive vomiting or diarrhea (and subsequent nutrient malabsorption), like celiac disease, Crohn’s disease, and ulcerative colitis. Similarly, people who’ve had surgery to remove parts of their digestive organs may also benefit from a multi.
Those Taking Certain Medications
Nutrients also can be depleted by certain medications. For example, proton pump inhibitors prescribed for acid reflux can decrease the body’s ability to absorb vitamin B12, and certain diuretics used to manage blood pressure can lead to decreased levels of calcium, magnesium, and potassium. Even certain oral contraceptives may impact nutrient levels.
Talk to your healthcare provider about how a drug may impact nutritional status when starting a new medication. If you’re curious about the potential effects of a medication you’ve been on for a long time, don’t be afraid to ask.
Potential Downsides to Multivitamins
There are some potential downsides to taking a multivitamin-mineral supplement. For starters, if you don’t need one, it can be an unnecessary expense. It’s also possible to overdo it on certain nutrients. “There also are tolerable upper limits for multivitamins,” Feller says. “When taken in excess specifically, the fat-soluble ones (vitamins A, D, E, and K) could potentially lead to toxic buildup in tissues. Therefore, it’s not recommended to supplement fat-soluble vitamins without having accurate lab work to verify that those vitamins or minerals supplements are needed.”
Meanwhile, water-soluble vitamins taken in excess simply don’t reach the cells in the body — that’s when you see that technicolor urine, Feller says. “You pee out what the body doesn’t use. It doesn’t mean the multivitamin isn’t working; it just means that you’re flushing your money down the toilet.”
Be mindful of minerals found in these products, too — especially if you take a few different supplements. For example, if you’re taking a multivitamin-mineral supplement that has a day’s worth of zinc and then you also take an immune-supporting supplement that provides a therapeutic dose of zinc, you may start to experience symptoms of excess zinc intake. Iron is another nutrient where getting enough is important, but too much can lead to severe adverse symptoms.
