Not everyone should be taking a multivitamin
In some situations, they can be helpful. In others, they can lead to dangerous nutrient deficiencies or imbalances. Experts weigh in on how to make an informed decision.
A large amount of vitamins can cause nausea, vomiting, dehydration, confusion, and organ damage, such as [to the] liver or kidney. Additionally, multivitamins containing certain minerals like calcium, magnesium, or zinc can interfere with the absorption of certain medications, such as antibiotics or thyroid medications.
That said, there are some situations in which a multivitamin may be helpful. Experts explain who may benefit from taking multivitamins and how we can make an informed decision about whether or not to include them in our daily routine.
Who should take multivitamins?
According to the National Institutes of Health (NIH), approximately one-third of all adults in the United States and one-quarter of adolescents take multivitamins. However, only a portion of them have received a recommendation from a healthcare professional to do so.
Whether or not you should take multivitamins depends on your individual nutritional needs, which can vary depending on factors such as age, gender, health status, and dietary habits. It’s important to consult with a healthcare professional before starting any supplement regimen to determine if it’s necessary and safe for you. While multivitamins can be a convenient way to help fill nutrient gaps, they shouldn’t replace a healthy diet and lifestyle.
For example, people who are pregnant or planning to become pregnant are one population who are recommended to take vitamin supplements. The Centers for Disease Control and Prevention (CDC) recommends they get up to 400 mcg of folic acid daily to help prevent neural tube defects (NTDs) or birth defects that occur when the neural tube doesn’t close properly in newborns, like spina bifida.
A multivitamin is recommended for pregnant people because it can be difficult to eat a healthy and well-balanced diet to meet the nutritional needs of the pregnancy and the mother. This is especially true if a person develops food aversions or has nausea throughout the pregnancy.
The CDC also recommends older adults take vitamins like B12 and D as they may have trouble getting enough nutrients from their diets. Often older adults have decreased appetites and don’t eat as much, but also, their bodies can have trouble absorbing the nutrients.
Individuals with nutrient deficiencies or absorption problems (people with cystic fibrosis, celiac disease, or other digestive disorders) and those who follow strict dietary restrictions (vegans, for example) also may benefit from taking multivitamins.
Who shouldn’t take multivitamins?
While taking a multivitamin may benefit some individuals, experts warn against taking multivitamins without consulting a healthcare professional.
Individuals who take certain medications, such as blood thinners, antibiotics, or diuretics, may require targeted supplementation rather than a multivitamin, says dietician Susan Schachter.
Multivitamins may contain ingredients that can interact with your other medications, making them less effective, ineffective, or even cause serious side effects. Multivitamins containing vitamin K, for example, can interfere with the effectiveness of blood thinning medications such as warfarin (sold under the brand Coumadin) and increase the risk of blood clots.
Coumadin is prescribed to prevent blood clot formation and stroke, and taking vitamin K could counter the effect of Coumadin and potentially put a patient taking Coumadin at risk.
Additionally, multivitamins often contain higher levels of vitamins and minerals than the recommended daily intake. People with kidney or liver disease may not be able to clear these nutrients from their bodies, which can lead to an excess buildup and damage to their organs. For example, taking too much vitamin A can cause nausea, dizziness, headaches, and even liver damage.
Taking multivitamins can even cause nutrient deficiency or imbalances, as taking too much of one nutrient can interfere with the absorption or use of other nutrients in the body (too much vitamin C, for example, can interfere with iron absorption).
You can think about nutrients as a team playing a game. For the team to do well, every player has to perform their role. If one player takes over, it might cause an imbalance. In the same way, when taking multivitamins, some nutrients can overshadow others. For example, taking high doses of zinc can inhibit copper absorption, leading to a possible copper deficiency.
What’s in a multivitamin?
Multivitamins are supplements, and the Food and Drug Administration (FDA) does not regulate their content. This means there’s a risk of inaccurate labeling or contamination, which can result in consuming harmful ingredients.
(What’s in melatonin? And is it giving you nightmares?)
Unlike medications prescribed by medical doctors, vitamins do not undergo the same rigorous evaluation of appropriate dosages and potential interactions for each individual patient. This is where an individualized approach becomes crucial—patients who mistakenly believe they’re pursuing a healthy path by taking multivitamins often find themselves deficient due to a lack of understanding regarding their specific nutritional needs and how to meet their health goals.
If you take multivitamins, look for products certified by a third-party organization, such as the US Pharmacopeia (USP), which verifies supplements’ quality, purity, and potency.
(Supplements may contain more than what’s on the label.)
While multivitamins can be tempting, the best way to obtain nutrients is via food consumption rather than supplements, highlighting the importance of identifying potential deficiencies and adjusting our diets accordingly.
The bottom line? Food is a true nutritional powerhouse, offering a spectrum of vitamins, minerals, and other essential nutrients that support our well-being. These nutrients keep us healthy and boost our immune system. Beyond nutrients, food contains fiber, antioxidants, and phytochemicals that can help protect against chronic diseases and improve our overall health.
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How these two vitamin supplements could do more harm than good
Fat-soluble vitamins are more likely to cause adverse effects if consumed in large doses. Here’s what the experts say about vitamins A and E
Everyone is always searching for that magic pill that will give them great health, but dietary supplements just aren’t it because the benefits often don’t outweigh the risks.
That’s not to say that some groups of people don’t need to supplement certain nutrients at certain points in their life; only that most people don’t need to supplement all the vitamins they may think they do.
Many don’t suggest the use of vitamin supplements unless there is a specific reason to do so.
Such advice is especially pertinent to fat-soluble vitamins.
Water soluble vs. fat soluble
Water-soluble and fat-soluble nutrients are absorbed differently in the body.
Water-soluble vitamins, which include vitamin C and all eight B vitamins, are dissolved, processed, and metabolized quickly in the body, and are not stored for later use.
Excess amounts of water-soluble vitamins are excreted in the urine.
On the other hand, fat-soluble nutrients—vitamins A, D, E, and K—are stored in the liver and adipose (fatty) tissue throughout the body for future use. While that helps to stockpile vitamin D during the summer sunshine to compensate for less sunlight exposure during winter months, it also means these vitamins can accumulate to potentially toxic levels.
It’s for that reason that Tolerable Upper Intake Level (UL) safety guidelines are provided by the National Academies of Sciences, Engineering, and Medicine to show the maximum quantity of certain vitamins that can be safely consumed without adverse health effects.
Fat-soluble vitamins tend to have lower ULs compared to water-soluble vitamins, emphasizing the need for caution when consuming them.
Among the four fat-soluble vitamins, the experts say vitamins A and E require more caution than others.
Concerns over vitamin A
Vitamin A is important for vision, growth, reproduction, and immune health. When consumed through natural food sources such as beef liver, sweet potatoes, spinach, carrots, or pumpkin pie within recommended doses— 900 micrograms daily for adult men and 700 micrograms daily for adult women—vitamin A is considered safe and essential.
The maximum daily upper intake limit for vitamin A is set at 3,000 micrograms, though it’s important to note that such allowances include consumption or absorption of all sources of vitamin A including from foods, supplements, and creams/lotions that contain retinol. (For context, consider that a single 3-ounce serving of pan-fried beef liver contains 6,582 micrograms of the vitamin.)
Exceeding the UL is dangerous and “one single large dose of it can contribute to toxicity. Such toxicity can cause issues like joint pain, liver damage, and birth defects.
Vitamin A is essential for normal fetal development, but too much of it can cause harm to both the mother and the developing fetus, causing an increased risk of birth defects of the eyes, heart, organs, and central nervous system.
Even in modest amounts and outside of pregnancy, “vitamin A supplements have been linked to skin irritation and an increased risk of bone fractures.
Research published earlier this year shows that vitamin A toxicity can also result from topical vitamin A (retinol) which is used to treat acne and psoriasis.
There have even been issues with vitamin A’s inclusion in multivitamins. “At one point, there was concern about the amount of vitamin A in multivitamin supplements and bone loss in older women,” explains Lichtenstein. She says it’s for this reason that some multivitamin brands now only include vitamin A as an ingredient in the form of beta-carotene. (Studies show that beta-carotene is converted into vitamin A in the body but carries less of the risks associated with other forms.)
What’s more, though some studies show that vitamin A derived from a balanced diet might reduce the risk of certain cancers; the NIH Office of Dietary Supplements notes that its supplement form might increase the risk of certain cancers because of vitamin A’s role in regulating cell growth and differentiation.
Longer-term, high-dose intake of vitamin A may also lead to liver disease, elevated blood lipids, bone and muscle pain and visual issues. Early signs of vitamin A toxicity may include dry skin, nausea, headache, fatigue, large liver, and hair loss, among other possible symptoms.
Concerns over vitamin E
Vitamin E is an even more controversial fat-soluble supplement.
When it occurs naturally in foods like wheat germ oil, avocado, fish, seeds, and nuts like almonds, hazelnuts, and peanuts, vitamin E is a powerful antioxidant that protects one’s cells from the effects of free radicals and improves skin and eye health.
However the safety profile of its synthetic form is a matter of debate among academics: Due to occasional reports of negative health effects of vitamin E supplements, scientists have debated whether these supplements could be harmful and even increase the risk of death.
One of the points of controversy and confusion regarding vitamin E is the fact that the nutrient has multiple forms‑some of which are more studied than others.
Vitamin E has eight chemical forms naturally, whereas most of the vitamin E supplements are synthetic alpha-tocopherol. It’s this alpha-tocopherol form that seems to carry more risks than other forms of vitamin E. This is an argument that it is better to eat foods that are rich in vitamin E rather than taking a synthetic supplement.
There is a need to better understand how the different forms of vitamin E act and interact in our bodies.
There’s also some confusion with how much vitamin E one can safely consume. The daily recommended dietary allowance (RDA) of vitamin E is 15 milligrams for both adult men and adult women, but its daily upper intake limit is 1,000 milligrams. The NIH Office of Dietary Supplements notes that “taking vitamin E supplements even below these upper limits might cause harm.
Indeed, clinical research shows that taking just 268 milligrams of vitamin E daily can increase the risk of prostate cancer in men by 17 percent. The form used in supplements has also been linked to lung cancer.
And you don’t have to reach toxic levels to experience downsides. The randomized trials of vitamin E have documented issues even in moderate amounts.
Higher doses of vitamin E supplementation may also interfere with blood clotting, which may cause hemorrhages.
Because of these issues and others, research published by the American Heart Association shows that supplemental vitamin E is no longer recommended at the higher levels needed to help protect against chronic disease like cancer, arthritis and cataracts.
Ultimately, it is about evaluating the balance between potential risks and rewards.
Lack of regulation for dietary supplements
Another area of concern for the experts that effects both water- and fat-soluble vitamins is that supplemental nutrients aren’t regulated by the U.S. Food and Drug Administration (FDA) using the same criteria as foods and drugs.
This can lead to unfounded claims and even labels that misrepresent the ingredients within each supplement bottle. “According to a recent independent analysis of 57 dietary supplements, 84 percent of them did not contain the amount of ingredients claimed, while 40 percent of the supplements did not contain any of the ingredients claimed. Moreover, 12 percent of the supplements contained undeclared ingredients, which is prohibited by the FDA.
It falls upon consumers, then, to choose reputable supplement brands and to purchase products that have been tested and marked by established third parties. And be very wary of any supplement that claims it can treat a disease since supplements are not allowed to make such claims.
It’s also important to check the daily dosage recommendations and upper limits of dietary supplements and to make sure that one supplement you’re taking won’t interfere with another. Talk to your doctor or dietitian to help determine the specific nutrients that you need.
It is a common misconception that vitamin supplements are beneficial for everyone. They can be beneficial for certain individuals in particular situations, but are not universally necessary, can be expensive, and are not entirely risk-free.
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Some vitamins and minerals simply work better when eaten together
When specific nutrients are used together in a meal, they can boost the nervous system, improve cardio health, and improve the immune response, to name a few benefits. “It’s like one plus one equals three.”
The concept of dynamic duos like Sherlock Holmes and Watson, or trios such as The Three Musketeers, doesn’t just apply to entertainment. It’s also relevant to your diet. That’s because when certain vitamins, minerals, or phytonutrients, are consumed together, they have a more powerful effect on your health than when they’re eaten alone—a concept called nutrient synergy.
In some cases, consuming certain nutrients together enhances the body’s ability to absorb one or the other; in other instances, the nutrients can have additive effects. This biochemical synergy can boost the functioning of the nervous system, and improve cardiovascular health, respiratory and musculoskeletal systems, and the immune response.
It’s always existed but we’re just discovering the importance of nutrient synergy—the idea that the whole is more impactful than the sum of its parts. With nutrient synergy, when you combine nutrients in the proper amounts, they’re more useful to the body than either one is by itself.
A study published this year in the American Journal of Clinical Nutrition, for example, found that when people consume a healthy fat (such as olive oil) along with foods that are rich in beta carotene—carrots or sweet potato—or lycopene which is found in tomatoes, the fat increases the bioavailability of these health-promoting phytochemicals.
[Many of these power nutrient pairings occur in Mediterranean cooking. Read about why the Mediterranean diet has stood the test of time.]
Other studies have found that pairing black pepper and turmeric increases the absorbability of turmeric’s active ingredient, curcumin, by 2,000 percent. Research has found that when magnesium is consumed with vitamin D, the mighty mineral helps activate vitamin D in the body so that it can positively influence bone growth and maintenance.
Some nutrients are just better together. It’s like one plus one equals three because they enhance each other.
Here’s a look at six dynamic nutrient combos that have synergistic effects.
Vitamin C and iron
The synergistic effect: The human body easily absorbs iron present in meat, poultry, and seafood. But the iron in plant foods is more difficult to extract.
Vitamin C helps liberate iron from plant-based foods and make it more absorbable,” Ayoob says. This matters because your body requires sufficient iron for proper growth and development and because the mighty mineral is needed to make hemoglobin, a protein in red blood cells that carries oxygen to every cell in your body and brain.
Insufficient iron can trigger iron-deficiency anemia, including weariness, lethargy, and issues with concentration and memory. A shortage of iron also reduces the immune system’s ability to fight off infections. In recent years, the power of this nutrient pair has been so well supported by randomized, controlled trials that a recent review published in 2022 in the journal Nutrients concluded that women with iron-deficiency anemia should increase their intakes of iron and vitamin C.
How to bring them together: For breakfast, have a bowl of iron-fortified cereal with sliced strawberries or kiwi fruit. For lunch, make a spinach salad with black beans, red pepper strips, and tomato slices. Or, stir-fry shrimp, broccoli florets, mushrooms, and sesame seeds, and call it dinner.
Consuming 25 milligrams of vitamin C, the amount in ¼ cup of broccoli, will double the absorption of iron present in this vegetable, says Joan Salge Blake, a registered dietitian and nutrition professor at Boston University.
Calcium, and vitamins D and K
The synergistic effect: You probably know that calcium and vitamin D are important for building and maintaining strong bones. But you may not realize how they interact or how vitamin K contributes to this mission.
Vitamin D helps you absorb calcium from your diet and vitamin K helps lay calcium down in the bone. The positive trio can help protect people from osteoporosis and reduce their risk of fracturing a bone. And because vitamin K helps direct calcium to where it belongs in the bones, it helps keep it from accumulating in the arteries where it can lead to blood clots.
How to bring them together: Make an omelet with eggs, spinach, mushrooms, milk, and cheese, or a smoothie with plain yogurt, fortified oat milk, blueberries, and a tablespoon of tahini. Prepare a salad with raw kale, roasted soybeans, and canned sardines, and lightly drizzle it with soybean oil before tossing it.
[Read more about why you probably aren’t getting enough vitamin D.]
Vitamins C and E
The synergistic effect: Both vitamins have strong antioxidant properties which means they help protect cells from damage caused by pollutants, exposure to ultraviolet rays, and other sources of unstable molecules called free radicals. But they do so in different ways. Vitamin E neutralizes free radicals and vitamin C removes them before they can damage cells.
In other words, they tag-team each other as antioxidants. In addition, a study in a 2020 issue of the journal Nutrients found that boosting intake of vitamins C and E reduced pain in people with fibromyalgia.
How to bring them together: Have a bowl of sliced strawberries and kiwi fruit, topped with sunflower seeds and chopped almonds. Make a salad with raw spinach leaves, tomato slices, red pepper slices, and a vinaigrette dressing. Stir-fry broccoli and cauliflower florets with peanuts and sunflower oil.
Vitamins B6, B12, and folate (B9)
The synergistic effect: This trio of B vitamins plays a vital role in reducing high levels of homocysteine, which are associated with a greater risk of cardiovascular disease.
In a study in a 2023 issue of JAMA Network, researchers tracked the intake and blood levels of folate, vitamin B6, and vitamin B12 and the incidence of metabolic syndrome—a cluster of conditions including high blood pressure, high blood sugar, abnormal cholesterol levels, and excess belly fat that increase the risk of heart disease, stroke, and type 2 diabetes—among 4,414 adults. Those with the highest intake of these three B vitamins had a significantly lower incidence of developing metabolic syndrome over a 30-year period.
Together this threesome also helps protect brain health and proper neurological function. “If you get enough of these together, it seems to slow down cognitive decline—it’s a long game.
How to bring them together: Have a bowl of fortified cereal with sliced banana and low-fat milk. Make a big salad with spinach, avocado, chickpeas, cooked bulgur, and a sprinkling of nutritional yeast. Or, have broiled sockeye salmon with asparagus and baked winter squash.
Potassium, magnesium, and calcium
The synergistic effect: Together these three minerals lower blood pressure, dilate blood vessels, and help with electrolyte balance, which is hugely important for proper nerve function.
In a study involving 16,684 adults, published in a 2022 issue of Nutrition Research and Practice, researchers found that people who had a higher intake of potassium, magnesium, and calcium had a lower risk of developing high blood pressure over a seven-year period—which in turn reduced the risk for heart disease, stroke, and even a particular eye disease.
The three minerals also help regulate heart rhythm and fluid balance in the body. An additional perk, according to a 2023 study in PLOS One, found that getting enough calcium, potassium, and magnesium, may help protect adults ages 40 and older from developing glaucoma.
How to bring them together: Make a pot of oatmeal, using milk instead of water, and top it with pumpkin seeds, chia seeds, and banana slices. Add chopped spinach to your lentil soup and grate some cheese on it. Have a baked potato topped with plain yogurt or cottage cheese and cooked broccoli florets.
Vitamin E and selenium
The synergistic effect: While this is a newly discovered combo, mounting research supports the ability of these nutrients to work together as potent antioxidants to protect cells from damage.
They help support immune cells and the function of immune cells—and they appear to enhance one another but the mechanism isn’t clear. Vitamin E can help regenerate selenium as it gets used as an antioxidant. What’s more, a 2021 study found that when they’re consumed together, vitamin E and selenium can control allergy symptoms and reduce airway inflammation from asthma in mice.
How to bring them together: Make your own trail mix with almonds, dried fruits, and Brazil nuts. Bake or roast halibut and serve it with cooked broccoli and brown rice. Make a smoothie with spinach, plain yogurt, kiwi slices, green grapes, and a drop of sunflower oil.
Real food. Not supplements.
Keep in mind that all of these pairings relate to the presence of these nutrients in foods, not supplements.
Think of it this way: It’s like going to the symphony—the first violinist is magnificent but when you put the whole orchestra behind the first violinist, it makes something magical. They work well by themselves but when they’re combined, the effect is even better.”