What Vitamins Should I Take? We Asked RDs to Weigh In

You probably have that friend who swears by the vitamin regimen they take every morning. Maybe they've even bragged about their newfound energy, glowing skin, and super-strong immune system. There's a good chance you've wondered if you should hop on the vitamin bandwagon and pop a slew of supplements to start your day, too.

Well, it turns out there's no one-size-fits-all when it comes to vitamins. So, what vitamins do you actually need, and how do you know if you need them? We spoke with dietitians to get the scoop on the most important vitamins for your health, how to tell if you have a nutritional deficiency, and which vitamin supplements are worth adding to your routine.

Experts Featured in This Article:

Amanda Sauceda, RDN, is a gut health nutritionist.

Amy Margulies, RD, LDN, is a Philadelphia-based nutrition expert and owner of The Rebellious RD.

Alyssa Simpson, RDN, is a digestive health dietitian in Phoenix.

Leah Oladitan, RDN, LD, is the founder of The Child Nutritionist.

Do You Need Vitamins?

First things first: Yes, everyone needs vitamins for optimal health. “Vitamins are critical across the lifespan, and there are some vitamins that play a larger role in different periods of life,” says Amanda Sauceda, RDN, gut health nutritionist. But that doesn't mean your vitamin intake has to be in the form of a pill or supplement.

Here's the deal: There are 13 essential vitamins: vitamins A, C, D, E, K, and the B vitamins (thiamine, riboflavin, niacin, pantothenic acid, biotin, B6, B12, and folate), says Amy Margulies, RD, LDN, Philadelphia-based nutrition expert and owner of The Rebellious RD.

Of those, “Vitamin D, vitamin C, and B vitamins are the MVPs for overall health,” says Alyssa Simpson, RDN, digestive health dietitian in Phoenix. “They help keep your immune system strong, your energy levels high, and your body resilient.”

Experts agree you should aim to reach the daily recommended amounts of these key vitamins from food before reaching for any supplements. “A healthy diet filled with fruits, vegetables, whole grains, and fish is one of the best ways to get the micronutrients your body needs,” Margulies says. “It's also a great way to naturally replace processed foods, red meat, and other less nutritious options with choices that truly support your overall health.”

Of course, there are a few caveats to be aware of. Some groups of people are more prone to nutritional deficiencies than others and therefore might need to supplement. “Vegetarians and vegans may lack vitamin B12 and iron, while those with limited sun exposure are at risk for low vitamin D,” Simpson explains. “Older adults often have reduced nutrient absorption, individuals with gut issues may struggle to absorb key vitamins and minerals, and pregnant women have higher nutrient needs to support their growing baby.”

Signs of Nutrient Deficiencies

How can you tell if you're nutrient deficient and need to be taking vitamins? “Bloodwork is the best way to confirm deficiencies in nutrients like vitamin D, iron, and B12,” says Simpson.

That said, there are some specific symptoms to look out for. Below are signs of common nutritional deficiencies, according to Margulies:

Benefits of Vitamins

You now know vitamins are super important for your health — but what are the actual benefits of each one? According to the National Institutes of Health (NIH), here are the top benefits of the 13 essential vitamins:

Beyond these vitamins, some key minerals for health are iron, potassium, magnesium, and calcium. Per the NIH, these minerals are necessary for many bodily functions. You need iron to carry oxygen from your lungs to every part of your body, while you need calcium to maintain strong bones, for instance.

As for the benefits of taking vitamin supplements? “Vitamin supplements act as a safety net,” Simpson says. “They're not a replacement for a healthy diet, but they can support energy, immunity, and overall health when nutrient intake falls short due to busy lifestyles or specific health needs.”

It's important to keep your expectations in check, though. While a multivitamin or other vitamin supplements might help support your overall well-being, don't expect them to be miracle workers. “Research shows dietary changes — not supplements — are crucial for improving health,” notes Leah Martin, RDN, LD, founder of The Child Nutritionist. “Taking a multivitamin does not show a benefit in preventing chronic diseases like heart disease, cancer, or mental decline with age — but following a Mediterranean diet does all of this and more.”

So, Which Vitamins Should You Take

For starters, it's not a bad idea to take a multivitamin even if you're a normal, healthy person, Sauceda says. “Multivitamins help to cover your bases, and they can be helpful for a healthy adult that knows there could be some gaps in their diet,” she explains. However, don't feel like you have to take a multivitamin. Even though you may not get enough of every vitamin daily, “chances are your weekly total is pretty good,” she says.

If you have nutritional deficiencies, that's a different story. As we stated previously, to find out if this is the case for you, you'll want to head to the doc first and get bloodwork to confirm, because taking too much of certain vitamins can have negative side effects.

“Supplements aren't risk-free,” Simpson says. “Taking vitamins you don't need or excessive amounts — especially without bloodwork to confirm a deficiency — can lead to toxicity or interact with medications, causing unintended health issues.” Simpson explains that too much iron or vitamin A can cause toxicity, while high doses of vitamin C or magnesium may lead to digestive issues like nausea or diarrhea. Once you know you're nutrient deficient, you should speak to your physician or a registered dietitian to come up with a supplement plan tailored to your individual needs, says Margulies.

Keep in mind that there are some common life experiences that may require supplementing with certain vitamins. One example? Vitamin B12 as an older adult.

“When you're an older adult you may need to emphasize B12,” says Sauceda. “This vitamin requires stomach acid to be able to be properly absorbed, and medications along with natural changes in the body due to aging can lead to absorption issues. We need B12 for brain health and healthy red blood cells.”

Pregnancy is another time in your life where you'll need to supplement with folic acid. “All people able to become pregnant should take 400 milligrams daily of folic acid to help prevent serious birth defects early in pregnancy,” says Martin.

Additionally, many Americans don't get enough vitamin D from their diets. Research varies on just how many of us are actually deficient. Past studies have suggested that anywhere from 42 percent to 95 percent of Americans aren't getting enough vitamin D. More recent studies suggest that 22 percent of Americans have a moderate vitamin D deficiency.

“It's hard to get enough vitamin D from food alone, with an RDA of 600 IU daily for most adults and 800 IU for those over 70,” Margulies notes. “While your body can make vitamin D from sunlight, sunscreen (which you should wear!) and limited winter sun in much of the US make it even tougher.”

Finally, certain eating plans and health conditions can make someone more likely to develop nutritional deficiencies than others and therefore could necessitate vitamin supplements. Case in point: “Vegetarians and vegans may lack vitamin B12 and iron,” says Simpson, while Sauceda explains that people with digestive disorders like celiac disease and inflammatory bowel disease may experience various nutritional deficiencies, including deficiencies in vitamin B12, vitamin D, and iron.

How to Choose Vitamins

Not all vitamins are created equally. “Vitamin supplements are not regulated like medication for safety or effectiveness,” says Martin. “Adverse events, including hospitalization and death, have been linked to supplements.”

That's why it's important to do your due diligence and choose vitamins from reputable brands. How to do this? Look for third-party testing, Simpson recommends. “Certifications like USP, NSF, or ConsumerLab indicate the supplement has been independently tested for quality, purity, and accuracy of ingredients,” she says.

You'll also want to check the ingredients and dosage to make sure you're getting the best product for your needs. “Prioritize active, bioavailable forms [of vitamins] — like methylated B12 for better absorption — and watch for fillers, artificial colorings, or sweeteners that may not support your health,” Simpson suggests.

Margulies adds that you want to ensure that the dose isn't too high “as some [supplements] contain excessive doses and too many specific vitamins and minerals can be harmful.” Your doctor can recommend a specific dosage for your needs if you have a specific deficiency, as everyone is different.

Margulies adds that if you have a nutritional deficiency, you should look for a supplement that provides the specific vitamin or mineral you need without any unnecessary extras so you don't end up taking too much of the nutrients you're not deficient in. “Your doctor or pharmacist can help recommend trusted brands for you,” says Margulies.

What if you just want to take a multivitamin? The NIH recommends choosing a multivitamin that contains some or all of your daily values and states that this should be safe for healthy people. The organization also suggests looking for a multivitamin designed for your needs (for example, there are special multivitamins for pregnant people, women, and seniors) to make sure you're getting the right amount of nutrients for you. You can also check out the NIH's dietary supplement fact sheet to learn more about a specific vitamin and its recommended daily allowance.

The bottom line on vitamins: “Supplements can be powerful tools for supporting natural health, much like food, but they shouldn't be taken lightly,” Simpson says. “It's possible to get excessive doses, encounter contaminants, or experience interactions with medications or other health conditions.” That's why consulting your provider is such a crucial part of the process. They'll help ensure you're getting the right dosage and that it's coming from a trusted source. “When chosen carefully and used appropriately, supplements can be some of the most effective tools to fill nutrient gaps and optimize overall wellness,” Simpson says.

Christina Heiser is a New York City-based freelance writer who's been covering health, beauty, fitness, and nutrition for over a decade. Her work has appeared in PS, Women's Health, Shape, Parade, and more.