Are multivitamins doing us more harm than good?


If you walk into a pharmacy or supermarket in Australia, you’re likely to see whole aisles dedicated to vitamin and mineral supplements. According to Roy Morgan, in 2018 over 8.3 million Australians bought vitamins, minerals or other supplements. The claims on these products range from promising to increase your energy levels through to treating the common cold, but are these pills actually improving our health or causing more harm?  

Dr. JoAnn Manson, a professor at the Harvard T. H. Chan School of Public Health states that “supplements are never a substitute for a balanced, healthful diet, and they can be a distraction from healthy lifestyle practices that confer much greater benefits”.

Understanding vitamins and minerals

Vitamins and minerals are nutrients that our body needs in small amounts. They are essential to many body functions including: 

  • growth
  • development
  • nerve function
  • blood clotting
  • immune function
  • eyesight

The amounts we need depend on a range of factors including our:

  • age
  • gender
  • diet choices
  • medical conditions
  • how active we are
  • genetics
  • level of exposure to sunlight and other environmental exposures like pollutants

We get the majority of our vitamins and minerals through the foods and drinks we consume every day. For most healthy individuals, a balanced healthy diet based on the five food groups  can  adequately provide all vitamin and mineral needs meaning you don’t need to take supplements. However, if you are restrictive on certain food groups, or eliminate them entirely, some supplementation could be needed. This is certainly the case for vegans who require vitamin B12 supplementation in the absence of animal products in their diets.

Supplements can not replace a healthy diet and health benefits are harder to achieve if a consistently poor diet with supplementation is chosen. It’s important to understand that having high doses of some supplements can increase the risk of interactions with medications and lead to detrimental health consequences.

Do you need to take supplements?

For the average person, if you follow the Australians Dietary Guidelines, you should be able to get all the vitamins and minerals you need from the food you eat. If you have an existing health condition or are highly active, you may need to be even more vigilant on your food choices to ensure you get enough of the nutrients you need.  If you can’t eat enough food to provide these, supplementation could be a complimentary solution to meeting your needs. If this sounds like you, consult an Accredited Practicing Dietitian or your GP to advise on what supplements you may need. The Australian Dietary Guidelines recommend a diet that is high in vegetables, fruit, and wholegrains with smaller but regular amounts of dairy products (mostly reduced fat) and lean meat or alternatives (like tofu, beans and other vegetable proteins). They also recommend limiting the amounts of added salt, sugar, alcohol and saturated fats in your diet.

There are some people who may still need supplements. These can include:

  • pregnant women who need to take folic acid or other supplements as advised by their doctor
  • vegans who may need to take B12, iron or omega fatty acid supplements
  • people with some medical conditions
  • highly active people or athletes

 You can use the CSIRO diet score online tool to see how balanced your diet is and where you may need to make some improvements to better meet your nutrient needs.

What foods contain vitamins and minerals?

Vitamins and minerals are found in highest quantities within foods that come from the five food groups. Some examples include:

  • Calcium – Dairy - milk, cheese, yoghurt plus tofu, Asian green vegetables, salmon (if consumed with the bones e.g. tinned)
  • Iron – Offal like liver and from animal flesh like red meat, pork and to a lesser extend in chicken, salmon and tinned tuna
  • Zinc – Crustaceans like oysters other seafood, red meat and chicken and to a lesser extent from brown rice, nuts and legumes (e.g. red kidney beans, chickpeas and lentils)
  • Folate – Plant based sources like beans, lentils, beetroot, green leafy vegetables, oranges and wholegrains like seeded breads and breakfast cereals and seeds

You can find out where other vitamins and minerals are found at Healthdirect Australia.

If your diet is unhealthy, can you take supplements instead?

Supplements can never replace a healthy diet. Although it might be tempting to think you can take a pill instead of eating your serves of fruits and vegetables each day, that’s not the case. If you’re not eating enough vegetables, supplements can help boost your stores and meet your daily needs. However, you’ll miss out on other components that occur naturally in wholefoods and we don’t understand the role of all of these components yet.

When we get our vitamins and minerals from whole foods, we’re able to absorb them more effectively. For example, our bodies absorb calcium more efficiently when it’s in the presence of vitamin D. Some research has also shown a better absorption when combined with lactose (the naturally occurring sugar found in dairy milk).

When we eat our five serves of vegetables each day, we’re also consuming a lot of fibres, both soluble and insoluble. Different types of fibre have  many benefits including reducing our cholesterol sand helping to manage our blood sugar levels. Some fibres have a prebiotic function which means that it helps to feed our gut microbiomes. Our gut microbiomes are made up of many microorganisms that help to digest and synthesise nutrients. These microorganisms also play a role in your metabolism, body weight, immune regulation and disease prevention. Our gut microbiomes also need vitamins and minerals to thrive which is why eating whole foods is a better way to get both at the same time.  

Are supplements safe?

Taking too many supplements can be toxic for our bodies and also interfere with other medications we may be taking.

For example if you take over 1.5mg of Vitamin A day over many years, it can make your bones  more likely to fracture. If you’re pregnant, it can also be harmful for your baby. Vitamin A is a fat soluble vitamin that accumulates in our fat cells over time.  If we end up storing too much, that’s when toxicity occurs. Rapid weight loss in people who have high vitamin A stores in their fat cells can cause a surge in blood vitamin A levels that can cause immediate and fatal health consequences.

According to the National Health Service in the UK, taking too much Vitamin B3 can result in skin flushes or even liver damage. It’s important to not go over the daily recommended intake for each nutrient and to remember that you may already be absorbing a certain amount from your diet that adequately meets your needs.

Who regulates the sale of vitamins and minerals in Australia?

The Therapeutic Goods Administration (TGA) regulates the sale of vitamins and minerals in Australia.  This government department ensures that:

  • all products only contain high quality and safe ingredients
  • all claims about the product are supported with research
  • the product only claims to treat minor health problems and not serious or life-threatening illnesses

All information contained in this article is intended for general information purposes only. The information provided should not be relied upon as medical advice and does not supersede or replace a consultation with a suitably qualified health care professional.


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