What Should Women Know About Vitamins and Supplements?

If you are a healthy woman, not pregnant, what vitamins or supplements should you take? Is that an easy question or a hard one?

When I had a practice focused on midlife women, some of my patients would come to the clinic with a bag full of bottles, big bottles, and little bottles of vitamins and supplements. They would ask me to look at them and help them think about which ones they should take, and whether should they be taking any others. I would do a little mental eye-roll, but I was grateful that they brought them in to ask about.

Well, now, I look at my little pile of pills at the breakfast table and ask the same question. What is the evidence that any of them do anything for my overall health? And is there a possibility of harm to my body, not just my bank account?

How to Choose Vitamins and Supplements

Let's go back to the question. If you are a healthy woman, not pregnant, what vitamins or supplements should you take?

The Subjectivity of "Healthy"

Well, you are a healthy woman. That's a very subjective phrase. And which of the 7 Domains of Health are we qualifying as healthy? Let's just say that your health record has no major medical problems. Many women are healthy according to their chart, but they don't feel the way they feel that they should feel. They want more energy, they want more peace of mind, they want more restorative sleep, they want to be thinner, they want a better sex life, and many healthy women take supplements or vitamins that offer them some of these things.

There's very little evidence that vitamins or supplements enhance the lifespan of healthy women who eat a balanced diet. Of course, many women do not eat a balanced diet and they spend all their lives inside, but we'll get to that.

Planning for Pregnancy

You are not pregnant. If all women ate a balanced diet with all the iron and folic acid they needed, they would not need prenatal vitamins, but many women do not. Some women eat a diet deficient in folic acid and therefore are at increased risk of a group of congenital anomalies called neural tube defects, problems where the fetus's nervous system doesn't develop normally.

Unfortunately, if you're going to decrease the risk of neural tube defects, you have to increase the folic acid in your diet before your OB prescribes prenatal vitamins at about eight weeks. You should take them before you become pregnant, which means you should plan your pregnancy.

Iron Deficiency

Next, many women have heavy periods and have given up a lot of their iron stores to a previous pregnancy or pregnancies. They enter the pregnancy with low iron and anemia, which gets worse with each pregnancy.

In the U.S., where people have access to food, a lot of food, iron deficiency in pregnancy is uncommon, but some women eat no sources of iron, meaning no meat, or very little, and have very heavy periods, so they're iron deficient.

Deliveries are always associated with blood loss, and if you're already low, you can get lower, and that can be a problem. Prenatal vitamins are specially formulated to have extra folic acid and iron.

Vitamin Guidelines and Recommendations

Now, what are vitamins? Vitamins are organic substances that are essential in small amounts to the normal function of the body of most animals. They act as coenzymes and precursors to normal metabolic function. They are present in natural foods.

Now, there are established guidelines about what the minimum daily requirement someone should have, and the labels of foods often have what percent of the minimum daily requirement is available with one serving of that food.

The U.S. Preventive Services Task Force has stated that for normal community living women, meaning women not in assisted living or nursing homes, there's no evidence that adding more vitamins can reduce the risk of heart disease or cancer.

And there is some evidence that women who take multivitamin pills actually don't live longer. They don't live as long as women who don't take vitamins.

If you eat a balanced diet, there are no vitamins you should take. Of course, if you're a vegan, you might not be getting the minimum daily requirement of B12, which is in meat and eggs. If you only eat macaroni and cheese, and I have those days, you're at risk of vitamin B deficiencies, and vitamin C deficiencies, but we are talking about women who eat a balanced diet.

Mineral Supplement Guidelines and Recommendations

Now, what are mineral supplements? Minerals like iron, magnesium, calcium, and zinc, as well as others, have some minimum daily requirements and are found in natural foods. They're usually added to the pills called vitamins and minerals.

There are deficiencies like iron deficiency in women who bleed a lot, run out of iron, and don't keep up with their diet. But healthy women eating a healthy diet don't need mineral supplements.

Well, what about all those other supplements? Fish oil, melatonin, coenzyme Q, and jillions of others? They are not regulated, there are no minimum daily requirements established, and there's no control over what's in the bottle that you purchase.

For healthy women, there's no need for supplements. And if there were, you would need to be very careful to know what is really in the bottle. If there was a supplement that was really good for something important, you could bet the pharmaceutical industry would jump on it, and produce it, and it would be FDA-regulated, and you would know in the bottle. But you don't know, so be careful.

Disease-Specific Vitamin and Mineral Needs

There are certainly some diseases where vitamins, minerals, or supplements would be indicated. People with macular degeneration of the eye may have a small decrease in the progression of the disease if they take a combination of certain vitamins and minerals. It's a small effect, but it's been shown to be useful in randomized trials, so now you can get a pill with that in it.

There are people with pernicious anemia where they can't absorb B12, and they get anemic. This disease is treated with high doses of B12 or injections of B12.

But if you're a healthy woman with a well-balanced diet, and I've said that three times now, four times, there are no recommended vitamins or supplements.

Vitamin D

Well, what about vitamin D? Vitamin D is important for our bone health and maybe it has some other effects on the body. We make vitamin D in our skin from sunshine. Isn't that amazing? We evolved outside in the sun, but some of us are inside all the time, and some of us are covered up with long sleeves, and a big hat, and a dermatologist on our shoulder, so some vitamin D would be good. Six hundred international units per day if you're under 70, and 800 per day after that. Of course, there are mushrooms, cod liver oil, oily fish, eggs, or vitamin-D-enriched milk. You get to choose.

Vitamin and Supplement Misinformation

But what if you heard from someone, saw on TV or in a magazine, or saw a person who specializes in another type of health practice, and they recommended something? They might say that something supports skin, hair health, or immune health, or is a substance from another cultural practice, such as Chinese herbal medicine, or Ayurvedic medicine, which is a practice from India. There is no regulatory process that requires that they tell the truth, or that there's really anything in those pills, so be careful.

Be hopeful, because hope is a powerfully positive supplement. Hope and optimism lead to better immune systems, lower risk of cancer, and more energy. I am working in my kitchen on a pill for that. But the pills are starting to look a bit like oatmeal chocolate chip cookies with dried cherries and butterscotch bits.

What is in my pile of morning pills? My prescribed pills for arthritis, a baby aspirin to prevent migraine, a vitamin that may slow macular degeneration, turmeric, which might help something or nothing, but gosh, those folks from India are smart, and beautiful, and live a long time, and I'm not that great at cook of Indian food, which has a lot of turmeric. There's some fish oil because it just might help my dry eyes according to the Moran Eye Center. Some of these are for scientifically valid reasons and some are covering my bases with the hopes for good intentions. I call them aspirational supplements.

The decision to take vitamins and supplements that have not been recommended to treat a specific dietary deficiency, like B12, iron, folic acid, or a disease is up to you.

Let's say you don't want to eat a well-balanced diet, just tea and toast, or butter and noodles, or just raw veggies. You don't want to be on the lookout for all the essential vitamins in minerals, so just take a multivitamin and mineral pill every day. Good for you.

Let's say that you have aspirational hopes for shiny thick hair, or more energy, and a supplement offers you those things. The scientific data for any claims are very scarce, but you are the only you there is. You get to choose, but choose wisely. Try to get vitamins and supplements that actually might have what they're advertising in the bottle, and not a lot of dust and scary stuff.

Consulting with Your Clinician

But whatever your decision, please tell your clinician. Some of these supplements have side effects in large doses, and some have adverse effects with your prescribed drugs. Eat your brightly colored fruits, and vegetables, and grains, and think about how good they are for you. Thanks for joining us on the "7 Domains of Women's Health."

_{updated: April 18, 2024
originally published: July 14, 2022}