What Vitamins Should I Take and Not Take?


vitamins not to take

People often ask “what vitamins should I take?” We believe it’s best to get your vitamins and minerals by eating a healthy diet.

When you eliminate junk food and empty calories from your diet and replace it with nutrient-rich food choices, you get the nutrients you need unless you eat a diet that restricts certain food groups or have difficulty absorbing certain vitamins and minerals.

We’re all for healthy eating – lots of vegetables, lean sources of protein (including plant-based ones) and moderate amounts of heart-healthy fats like those in nuts and olive oil.

If you’re unsure what to eat, read about the Mediterranean diet, one of the healthiest diets in the world.


Why People Take Vitamin and Mineral Supplements

Some people think of vitamins and other supplements as a cheap insurance policy, a way to make up for what’s lacking in their diet. Sounds like a smart idea in theory, huh?

There’s a reason why you don’t want to take high doses of a vitamin or mineral without giving it careful consideration. When you take megadoses of a vitamin or mineral, it affects the absorption of other vitamins and minerals and creates an imbalance.

An example of how taking a supplement affects the absorption of other nutrients is zinc. Zinc is an essential mineral you need in small amounts for a healthy immune system. YOu also need it for wound healing, fertility and for a good sense of taste and smell.

If you take a zinc supplement without taking copper, you can develop a dangerous copper deficiency because zinc reduces the absorption of copper. Fortunately, most zinc supplements have copper added to prevent this.

There’s some evidence that you need more dietary zinc due to absorption issues after the age of 65. Low zinc levels have been linked with poor immune function and inflammation. If you take a zinc supplement, make sure it contains copper too.

Zinc, iron, magnesium and calcium can all block the absorption of each other because they’re similar in structure.

In general, you shouldn’t take large doses of a particular vitamin or mineral unless you have a deficiency or you’re taking it because you have a health problem that a certain vitamin or mineral can help.

For example, if you have certain intestinal disorders like inflammatory bowel disease, you may not fully absorb some vitamins and may need to supplement. Another example – if you have a deficiency of vitamin D or vitamin B12, as measured by a blood test, you need a vitamin D or vitamin B12 supplement.

If you eat a vegan diet, you may not get enough of some vitamins and minerals. For example, a vegan diet, in many cases, doesn’t offer enough calcium, zinc and vitamin B12.

If you’re on a calorie-restricted diet to lose weight, you may temporarily need a multi-vitamin and mineral supplement since you’re not consuming as much nutrient-rich food. Hopefully, the foods and beverages you’re choosing are smart ones.


If you’re pregnant or planning on becoming so, you need to supplement with folate to prevent brain and spinal cord birth defects. Most doctors recommend a multivitamin with folate and iron during pregnancy.

What Vitamins Should I Take and NOT Take?

Now let’s look at what NOT to take or take only with the advice of a doctor.

Beta-Carotene Supplements

Beta-carotene is an antioxidant related to vitamin A. You find it naturally in “orange” foods like sweet potatoes and carrots. Getting beta-carotene naturally from foods is a good thing. Beta-carotene is important for a healthy immune system and visual health.

What you don’t want to do is take a beta-carotene supplement unless you have a medical reason to do so. Research shows taking high doses of supplemental beta-carotene is linked with a higher risk of mortality and an increased risk of prostate cancer in men. Instead, eat your carrots and sweet potatoes.


Vitamins A, C and E

Some studies show taking supplemental doses of vitamins A and E may be harmful. Once thought to be helpful for preventing prostate cancer, a study showed supplemental vitamin E INCREASES prostate cancer risk in men.

Vitamin A can build up in your body at high doses and lead to problems such as liver inflammation and osteoporosis.

Vitamin C doesn’t build up in your body like vitamin A can. When you take large amounts, it’s excreted in your urine. What it can do is cause nausea, diarrhea and stomach upset. Plus, high doses increase the risk for kidney stones.

In addition, there’s no strong evidence that taking high doses of vitamin C is beneficial. You can get all the vitamin C you need for the day by eating a large orange.

Vitamin B6

Vitamin B6 is a member of the B vitamin family, vitamins essential for energy production. Most people get enough vitamin B6 from diet alone. One exception would be alcoholics, who are at greater risk for vitamin B6 deficiency. Don’t take it unless you really need it. High doses of vitamin B6 can lead to nerve damage.


Selenium is a mineral your body needs in trace amounts. At one time, experts believed selenium might lower the risk of certain forms of cancer due to its antioxidant activity. This idea was dispelled after a study showed an increased risk of prostate cancer in men taking selenium alone or a selenium/vitamin E supplement together. In this study, selenium only increased the risk of prostate cancer in men who already had high enough levels of selenium.

Some studies looking at populations that eat a lot of selenium-rich foods show they have a lower risk for certain types of cancer including lung cancer, bladder cancer and cancers of the digestive tract.

It’s possible that getting selenium naturally through foods may offer some protection against cancer. For now, get selenium by eating selenium-rich foods.


The best natural sources of selenium is seafood and organ meats. Cereals, grains and dairy products are other good sources. The best source? Brazil nuts top the list.


Some women need supplemental iron prior to menopause to avoid a deficiency. If you’re a man or post-menopausal, you don’t need supplemental iron unless you have a known deficiency.

Iron can build up in tissues and organs if you get too much of it. Plus, iron is a pro-oxidant, the opposite of an antioxidant. It damages cells at high doses.

Our advice – check an iron level before taking a multivitamin with iron or an iron supplement.


Calcium supplements are somewhat controversial right now. In the past, some studies linked calcium supplements with a higher risk for heart disease. More recent studies have NOT shown this link. Still, it’s best to get calcium from dietary sources whenever possible.


If you take a calcium supplement, consider taking a vitamin K-2 supplement as well. Preliminary research shows vitamin K2 helps to direct calcium to bone, where it should be, and not to the inner walls of arteries where it could contribute to heart disease.

What Vitamins Should I Take: The Bottom Line?

Try to get your vitamins and minerals by eating a healthy diet. If you eat a diet that restricts certain food groups, like a vegan diet, consider taking a calcium, B12, vitamin D and zinc/copper supplement.

If you have certain medical conditions, have problems absorbing some vitamins or minerals, are pregnant or eating a calorie-restricted diet, you may need to supplement.

Don’t take a vitamin or mineral supplement on the basis that it’s “probably not harmful.” It could be.


Am J Clin Nutr May 2009 vol. 89 no. 5 1627S-1633S.
Oregon State University. “Zinc deficiency mechanism linked to aging, multiple diseases”
MedLine Plus. “Beta-Carotene”
Fred Hutchinson Cancer Research Center. “Selenium and vitamin E supplements can increase risk of prostate cancer in some men”
JNCI J Natl Cancer Inst (2014) djt456.doi: 10.1093/jnci/djt456.
National Institutes of Health. “Vitamin B6”

Kristie Leong M.D.

Dr. Kristie Leong and Dr. Apollo Leong are physicians helping you to lead a healthy lifestyle by sharing nutrition and fitness tips and keeping you abreast of the latest health news.

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