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Everything You Need to Know About Vitamin Supplements

What are the best supplements for our unique needs? We asked the experts.
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Art Credit: Katherine Messenger

Remember taking those daily chewable Flintstone multivitamins as kids? I sure do! But somewhere along the way, most of us stop taking an extra hit of vitamins, except perhaps to avoid getting sick when flu season is upon us. But should we be taking a little extra to help us out? And if so, how much should we be taking? What are the best supplements for our unique needs? Rather than wind down the Internet rabbit hole, we asked some experts to give you the dish on taking supplements for grown-ups.

Why take vitamins?

Regardless of your lifestyle, vitamins are a helpful way to boost your immune system. Many experts say that vitamins do have a place in our diets, but that their primary function is to fill in small nutrient gaps. “They are ‘supplements’ intended to add to your diet, not take the place of real food or a healthy meal plan,” says Kathleen M. Zelman, MPH, RD, LD.

Reasons for taking vitamins include:
> Pregnancy. Prenatal supplements help prevent deficiencies that may contribute to chronic health conditions.
> Maintaining bone mass, particularly for osteoporosis prevention. Iron and calcium are particularly important for this.
> Boosting your immune system. Vitamin C benefits your immune system, helps prevent heart problems, and allows cuts or wounds to heal faster.
> Preventing folic acid deficiency which is common for women in their childbearing years.
> Assisting a restricted diet. Picky eaters or those with dietary restrictions who have limited variety within food groups often need some extra help to make up for what they aren't getting in their daily meals.

Do I need to take vitamins with food?

Taking vitamins with or without food varies on the type of vitamin and the time of day. Dr. Melissa Dorval, R.D., states, “Some vitamins and supplements should be taken with food or a meal for best absorption while you may need to take others on an empty stomach.” She shares that most vitamins such as daily multivitamins and vitamin C, E, and B-complex can be taken with our breakfast meal. Check the label for whether you should take your vitamin with food.

She warns, “We do not recommend taking calcium along with your multivitamin if your multi contains iron. The calcium may interfere with the iron’s absorption. If you take a multivitamin containing iron with your breakfast meal, take your calcium with the other meals you consume throughout the day, such as lunch and dinner.” Keep in mind that the form of calcium you take determines whether you should take it with or without food. Calcium carbonate requires consumption with food while you can take calcium citrate with or without food.

Is it possible to overdose on vitamins? 

It is possible to have an ‘overdose’ on vitamins with varying side effects. Having too much vitamin C can cause diarrhea or stomach cramps. It could even lead to fatigue or mild nerve damage. Too much calcium can cause constipation, bloating, and even kidney stones. Excessive or large amounts of folate can increase the risks of cancers in some people. Overdosing on iron can cause abdominal pain, constipation, nausea, vomiting, or even fainting.

David Katz, MD, Director of the Yale University Prevention Research Center states, “Scientists don’t yet know if routinely getting a little bit too much of a vitamin or mineral (as opposed to a mega dose) is a problem. There might be hints of concern, but they would be very subtle signs.”

Which vitamins and supplements should I be taking in my 20s and 30s? And how much?

The main concern for women in their 20s and 30s is getting enough calcium, vitamin D, folic acid, and iron. Always read the directions on the bottle for the recommended dosage (and click here for handy charts from the FDA, broken down by age and gender).

Our bodies need calcium to maintain strong and healthy bones, which is why it’s important for adults as we age. “Women start losing bone density in their 20s,” says Mary Ellen Camire, Ph.D., a nutrition professor at the University of Maine at Orono. “Calcium is your single best defense, and you should start taking it now.”

The Fix: The recommended dosage for calcium is 1,000 mg/day for women between the ages of 19 and 50. It's best to get calcium naturally through dark leafy greens such as kale or broccoli, or in dairy products like yogurt, milk, and cheese. But since many women don't get enough calcium through diet alone, supplements are a helpful boost. It's best to take smaller doses (500 mg or less) with meals to allow for maximum absorption into the body (but not at the same time as iron supplements—see above).

Vitamin C
Vitamin C has many healing and antioxidant powers. It doesn’t cure the common cold. But it does strengthen our immune system by protecting us against free radicals. Free radicals contribute to heart disease, cancer, and arthritis.

The Fix: Find vitamin C in all fruits and vegetables, especially in citrus fruits, red pepper, and broccoli. For vitamin intake, the recommended amount is about 75 mg/day. If you’re pregnant, take 85 mg/day. And if you’re breastfeeding, take 120 mg/day.

Folic Acid (Folate)
Folate helps create new cells alongside maintaining red blood cells. It also maintains balance in our nervous system’s message-carrying molecules for proper brain function. One of the biggest ways folate helps women is by preventing anemia, which is especially important to any pregnancy. Folate deficiency during pregnancy can lead to complications including premature births or birth defects.

The Fix: The daily recommended intake for women is 400 mg/day. This increases to 600 mg for pregnant women. You can find folate naturally in leafy green veggies, fruits, beans, and enriched cereals, breads, rice, and pasta.

Iron carries oxygen within the body, produces red blood cells, and regulates body temperature and proper cell growth. An iron deficiency causes our bodies to reduce the production of red blood cells leading to anemia. Anemia is common in women, causing side effects such as fatigue and weakness.

The Fix: Find iron in red meat, chicken, fish, turkey, cereal, whole grains, beans, and dark leafy greens. The recommended dosage for iron is 18 mg/day, 27 mg if you’re pregnant, but only 9 mg if you’re breastfeeding. The recommended daily allowance for vegetarians is 1.8 times higher than for people who eat meat.

While vitamins can help us in many ways, consult your doctor about what would work best with your body, health, and lifestyle, particularly if you're pregnant or trying to conceive.