Do Vitamins Work? Mayo Clinic Has the Answer

There has been much debate about whether or not vitamins really work, with some studies suggesting that they do not provide any significant health benefits, while others claim that they can help to prevent a wide range of diseases and disorders. With so much conflicting information out there, it can be difficult to know what to believe.

Fortunately, the Mayo Clinic – one of the most respected medical institutions in the world – has conducted extensive research into the efficacy of vitamins in promoting good health. In this article, we will take a closer look at their findings to help you make informed decisions about your own supplement regimen.

What Are Vitamins?

Vitamins are organic compounds that our bodies need in small amounts to function properly. They play a vital role in many of our bodily processes, including metabolism, immune function, and the regulation of gene expression.

There are thirteen essential vitamins that our bodies need to stay healthy:

  • Vitamin A
  • Vitamin C
  • Vitamin D
  • Vitamin E
  • Vitamin K
  • Thiamine (B1)
  • Riboflavin (B2)
  • Niacin (B3)
  • Pantothenic acid (B5)
  • Pyridoxine (B6)
  • Biotin
  • Folate (B9)
  • Cobalamin (B12)

Do We Get Enough Vitamins from Diet?

While it is certainly possible to get all of the vitamins we need from a healthy, balanced diet, many people do not consume enough nutrient-dense foods to meet their nutritional needs. Some estimates suggest that up to 40% of Americans are deficient in one or more essential vitamins.

This is where supplements come in. By providing concentrated doses of certain vitamins, they can help to fill in any gaps in our diets and ensure that our bodies have all of the nutrients they need to stay healthy.

Do Vitamins Help to Prevent Disease?

One of the biggest claims made by advocates of vitamin supplementation is that they can help to prevent a wide range of diseases and disorders, ranging from the common cold to cancer. But what does the research say?

Vitamin C

Vitamin C – also known as ascorbic acid – is one of the most popular vitamins for preventing and treating the common cold. While there is some evidence to suggest that it may help to reduce the severity and duration of symptoms, overall, the evidence is mixed.

According to the Mayo Clinic, “Taking vitamin C supplements regularly doesn’t seem to reduce the risk of getting a cold, but it may help reduce symptoms, including the severity and duration of the common cold, when taken within 24 hours of onset of symptoms.”

Vitamin E

Vitamin E is a powerful antioxidant that is often touted as a potential prevention strategy for a variety of conditions, including heart disease, dementia, and cancer. However, the evidence is not clear-cut.

According to the Mayo Clinic, “Taking vitamin E supplements does not seem to prevent heart disease or cancer in most people. It’s also not clear whether vitamin E supplements can prevent dementia or cognitive decline.”

Vitamin D

Vitamin D is essential for bone health, and some studies have suggested that it may also play a role in preventing a variety of other conditions, including heart disease, cancer, and autoimmune disorders.

However, the Mayo Clinic notes that the evidence is still inconclusive:

  • “Some studies have suggested that taking vitamin D supplements can reduce the risk of certain types of cancer, such as colorectal and breast cancer.”
  • “However, other studies have found no such benefits.”
  • “Research has also found mixed results regarding the relationship between vitamin D and heart disease.”

The Bottom Line

So, do vitamins really work? The answer, as with many things in the field of medicine, is complicated.

While some vitamins have been shown to provide health benefits, the evidence is often mixed or inconclusive. In general, it is best to get your vitamins and minerals from a healthy, varied diet supplemented with vitamins only when necessary and as recommended by your doctor.


Q: Do vitamins have any side effects?

While vitamins are generally safe when taken in recommended doses, some can cause side effects, especially when taken in high amounts. For example, taking too much vitamin C can cause diarrhea, while high levels of vitamin A can be toxic.

Q: Can vitamins be harmful?

Yes, in some cases, taking too many vitamins can be harmful. For example, high doses of vitamin A, vitamin D, and iron can be toxic.

Q: Do we need to take vitamins every day?

It depends on the vitamin. Some vitamins – like vitamin C – are water-soluble, meaning they’re not stored in the body and need to be replenished daily. Others – like vitamin D – can be stored in the body and don’t need to be taken every day.

Q: Should I take a multivitamin?

It depends on your individual needs. If you have a well-balanced diet and are not deficient in any essential vitamins, a multivitamin may not provide any additional health benefits. However, if you have trouble getting enough of certain vitamins – like vitamin D or B12 – a multivitamin may be helpful.

Q: Should I talk to my doctor before taking vitamins?

Yes, you should always talk to your doctor before starting any new supplement regimen, as they can advise you on the best course of action based on your individual health needs.


  • Mayo Clinic. (2021). Vitamins and Supplements: Nutrition in a Pill?
  • Mayo Clinic. (2021). Vitamin C: An Essential Nutrient for Good Health
  • Mayo Clinic. (2021). Vitamin E: Does it Prevent Heart Disease?
  • Mayo Clinic. (2021). Vitamin D: Can it Prevent Cancer?

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