For decades, studies have concluded that multivitamins do little, if any, to prevent chronic disease. Yet a third of American adults get one every day, according to the National Institutes of Health (NIH). If you’re still wondering if you need a multi, here’s what they want you to know.
What exactly are multivitamins?
The term “multivitamin” is a misnomer, especially since these supplements often contain more than just vitamins. “Manufacturers can include a combination of vitamins and minerals, but they can also add other ingredients, such as herbs, antioxidants and amino acids,” says Sonya Angelone, RDN, a nutritionist in a private practice in the San Francisco Bay Area. “Depending on the brand, the formulas can vary significantly and are often designed for a specific group based on age, gender or health condition.”
Although multis have been around since the 1940s, according to past research there is still no standard definition of the nutrients they should contain. It’s surprising considering they’re the most popular dietary supplement in the United States, according to the Centers for Disease Control and Prevention (CDC).
What are the nutrients commonly found in multivitamins?
In a perfect world, a multivitamin would provide all the vitamins and minerals needed to stay strong and healthy in the right amounts. In reality, this is usually not the case, and an increasing number of multis exceed the daily value (DV; the recommended amount of a nutrient most people can consume in a day) for many vitamins and minerals. How come?
“There is a lot of competition in the supplement market, and adding a large dose of a nutrient seems like a ‘good deal’ to the consumer,” says Lisa Young, PhD, RDN, a New York City nutritionist and author of Finally Complete, Finally Subtle. “However, this could be problematic, as more than one nutrient in supplement form is not necessarily better.”
Take fat-soluble vitamins like A, D, E, and K, for example. As we store these nutrients in our fatty tissue, excessive doses can build up in the body to dangerous levels, according to Mount Sinai. Too much of some minerals, such as iron, can also be toxic and can interfere with the absorption of other nutrients, according to the NIH.
Although formulations differ from manufacturer to manufacturer, the typical multi, such as Bayer’s One A Day, contains the following nutrients:
Additionally, some women’s formulas contain iron. Just know that if you take gummies the list could be considerably shorter. This is because some nutrients, particularly iron, have unpleasant flavors that would ruin the candy-like taste that makes gummy candies so popular, reports ConsumerLab, an independent nutrition testing company.
What are the advertised benefits of multivitamins?
If you’re not always eating right, a multi can be a helpful way to fill in nutritional gaps, the CDC says. True nutritional deficiencies are rare in the United States, with less than 10 percent of Americans affected, according to information gathered between 2003 and 2006 by the CDC. For the most part, these deficiencies are limited to four nutrients: vitamin B6, vitamin D, iron and, to a lesser extent, vitamin C. Furthermore, no supplement lives up to the nutrient package a balanced diet can provide, says the dr. . Young. After all, food provides not only vitamins and minerals; it also provides proteins, carbohydrates, fats and fibers.
While much of the seven decades of multivitamin research has concluded that taking one will likely not protect against chronic disease, the NIH notes that most of these studies are not of high quality. More often than not, this body of research has relied on people’s reports of their diets over relatively short periods of time. It’s not as reliable or effective as the studies where researchers give someone a daily multi and then follow it for decades to see if they develop heart disease or cancer.
So, without more rigorous research, here’s what we currently know about the impact of multivitamins on various conditions.
Cancer The largest and longest-running randomized trial of multivitamins, known as the Physician’s Health Study, looked at the use of multivitamins among 14,000 American male doctors aged 50 and over. The results showed a modest reduction in the overall cancer incidence in men who took a multivitamin compared with those who did not, but the group also had a lower average BMI and smoking incidence than the general population. “Some studies have supported these claims, while others haven’t shown the same result, so we don’t know for sure yet,” says Alexander Michels, PhD, research coordinator and head of communications at the Linus Pauling Institute at Oregon State University.
Heart disease When it comes to heart health, the Physician’s Health Study was even less optimistic. After following 13,316 male doctors for an average of 11 years, he concluded that multis offered no protection against heart attack, stroke, or death from heart disease.
Brain health “As with cancer, the evidence here is mixed,” says Dr. Michels. “One [of the largest] recent clinical trials on multivitamins, called the COSMOS study, have reported a reduction in cognitive decline, but the Physicians Health Study did not report the same effect ”.
Bone health Even though the results are mixed, Michels is still a fan of taking a strong bone multivitamin. “Bone health is not just about vitamin D and calcium,” he explains. “Healthy bones require many different minerals and vitamins, most of which are provided by a multivitamin supplement.”
The potential risks of taking a multivitamin
Taking a vitamin may seem pretty harmless, but you might be surprised to learn that these supplements can be risky for some people. Although they are regulated by the FDA, they are not subject to the same standards as prescription drugs. In addition to the potential toxicity when over-supplementing or combining multivitamins with other supplements, research has found that some vitamins and minerals can have dangerous interactions with several medications, including:
So, if you are considering a vitamin supplement, be sure to speak to your doctor first. It can also help you time it correctly. “To avoid a potential interaction, it’s best to take a multivitamin several hours before or after taking medications,” says Young.
Who Should Take a Multivitamin?
While food is superior to supplements, a multi can be beneficial for some people. According to the NIH, these supplements may be a good option if:
- They are vegan or strictly vegetarian
- You suffer from celiac disease The National Celiac Association recommends asking your doctor for multivitamins if you are celiac or are following a gluten-free diet, as you will need to avoid many of the fortified foods that provide the necessary nutrients.
- They are over 50 years old With age, your body’s ability to absorb, produce or use certain nutrients such as vitamins B12 changes.
- I’m pregnant (or planning to become pregnant), which changes your nutritional needs
- Follow a strict calorie or weight loss diet
- Having a chronic illness which interferes with your ability to absorb nutrients
People with a known vitamin deficiency or those who may have a poor appetite will want to take a multivitamin as directed by their doctor, says Young.
When to take a multivitamin
“The best time is when you remember it and do it regularly,” says Young. “For most people it would be in the morning with some food that contains some healthy fat, such as eggs, avocado or nut butter, to help you absorb its fat-soluble vitamins better.”
What to look for in a multivitamin
When it comes to choosing a multi, many nutritionists have a philosophy of less is more. “Since we also eat food and hopefully get nutrients from a well-planned diet, I recommend looking for a supplement with no more than 100 percent of the daily value for each nutrient,” says Young. “In fact, I often advise clients who want to take a multivitamin to take it three times a week rather than every day.”
Of course there are exceptions. So, if you have a health condition or are taking medications that impair your ability to absorb certain nutrients, speak to a registered dietitian or your doctor.
Is a multivitamin right for you?
The answer really depends on your eating habits and your health. “Sure, you can get most of the nutrients you need from the foods you eat, but people just aren’t doing it,” says Michels. “National polls in the United States have shown this over and over again: Many of us are not consuming enough vitamins A, C, D and E, or magnesium, calcium and potassium.” In the end, if your diet is great, you probably don’t need it. But if you’re not always eating right, pregnant, over 50, or living with a chronic health condition, a multiple might be a good idea, so talk to your doctor.