Multivitamins are a type of supplement that contain a variety of minerals and vitamins. In most cases, multivitamins won’t be harmful. But sometimes, taking large doses of certain nutrients can have serious side effects. For most of us, a healthy, balanced diet will provide us with all the nutrients we need. 

Do you need to take supplements? 

The first thing to note is that not everyone needs a supplement. For most of us, it’s possible to get all the nutrients you need from a healthy, balanced diet. Plus, supplements can’t always mimic the wide range of benefits you get from eating nutritious foods.

So, the first step is to understand if you need to take one. Your age, your diet, or if you have a certain medical might require you to supplement your diet. 

A blood test can be a useful way to understand if you’re getting enough nutrients from your diet. Your results will tell you whether you’re deficient in anything and help you understand what supplement you should be taking.

What are multivitamins? 

Multivitamins are a type of supplement that contain a variety of minerals and vitamins. The nutrients in multivitamins vary between brands and products.

Vitamins commonly found in multivitamins include:

  • Vitamin A
  • B vitamins — like folic acid and vitamin 12
  • Vitamin C 
  • Vitamin D
  • Vitamin E
  • Vitamin K

Minerals commonly found in multivitamins include:

  • Calcium
  • Iodine
  • Iron
  • Magnesium
  • Manganese
  • Molybdenum
  • Selenium
  • Zinc

In addition to vitamins and minerals, multivitamins might also contain things like herbs, amino acids, and fatty acids.

Are multivitamins good for you?

Despite some bold claims, multivitamins might not be as good for your health as some companies make out. They’re often believed to help reduce your risk of chronic diseases, like heart disease. But, extensive reviews don’t show this. So in healthy people, it’s unlikely they have any benefit. 

Also, if you do take a multivitamin and are on medication, make sure these won’t interact with each other. This is why it’s a good idea to speak to a doctor or pharmacist before starting any supplement.

Multivitamins: Can you take too much?

In most cases, multivitamins won’t be harmful. But sometimes, taking large doses of certain nutrients can have serious side effects. 

Water-soluble vitamins

If you have too much of a water-soluble vitamin, like vitamin C or B vitamins, your body will flush the excess out so it will rarely be harmful. But mega-doses can potentially cause issues. For example, too much vitamin C supplement can cause diarrhoea and too much vitamin B7 can cause liver damage.

Fat-soluble vitamins

In the case of fat-soluble vitamins, these can build up in your body — potentially causing harmful side effects. For example, too much vitamin A over many years might affect your bones and increase your risk of fractures as you age. Or taking too much while pregnant can harm your unborn baby.

Minerals, like iron, can also be harmful if you have too much.

As a result, it’s better to understand if you’re deficient in a particular nutrient and to take a supplement only with that nutrient.

Which supplements are best to use? 

There’s a lot of misinformation out there about supplements. We’ve created some handy articles that help you understand what to look for: 


Holmquist, C., Larsson, S., Wolk, A., & De Faire, U. (2003). Multivitamin supplements are inversely associated with risk of myocardial infarction in men and women—Stockholm Heart Epidemiology Program (SHEEP). The Journal of nutrition, 133(8), 2650-2654.

Huang, H. Y., Caballero, B., Chang, S., Alberg, A., Semba, R., Schneyer, C., ... & Vassy, J. (2006). Multivitamin/mineral supplements and prevention of chronic disease. Evid Rep Technol Assess (Full Rep), 139, 1-117.

Jenkins, D. J., Spence, J. D., Giovannucci, E. L., Kim, Y. I., Josse, R., Vieth, R., ... & Paquette, M. (2018). Supplemental vitamins and minerals for CVD prevention and treatment. Journal of the American College of Cardiology, 71(22), 2570-2584.

Koro, C. E., Bowlin, S. J., Bourgeois, N., & Fedder, D. O. (2004). Glycemic control from 1988 to 2000 among US adults diagnosed with type 2 diabetes: a preliminary report. Diabetes care, 27(1), 17-20.

National Health Services (2017).Behind the headlines: most multivitamins and supplements are wasted money. Retrieved 4 May 2020 from

Watkins, M. L., Erickson, J. D., Thun, M. J., Mulinare, J., & Heath Jr, C. W. (2000). Multivitamin use and mortality in a large prospective study. American journal of epidemiology, 152(2), 149-162.

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Cesare Attuoni

Written by Cesare Attuoni

2nd Jun 2020 • 4 min read