Updated 14 August 2017

Are vitamin supplements fatal?

Taking vitamin supplements may not be good for you. What's more, these pills may also be dangerous and, in some cases, fatal. DietDoc gives perspective on this controversial topic.

Taking vitamin supplements may not be good for you. What's more, these pills may also be dangerous and, in some cases, fatal.

According to the Association for Dietetics in South Africa, this shocking news is based on a recent review prepared by NICUS (Nutrition Information Service of the University of Stellenbosch). The NICUS article is entitled "Are We Oxidising Ourselves with Antioxidants? Be Careful of the Supplements You Take".

New research
The latest so-called 'meta-analysis' of the results of a large number of research studies involving many thousands of experimental subjects in many different areas of the world, has come to the startling conclusion that "pill popping" of vitamin supplements increases the risk of mortality (death).

Different types of studies
Let me try to explain what this type of research entails. You are aware of the fact that scientists are studying many different aspects of diet and health. There are a number of different ways in which scientists do this. Firstly there are so-called 'Epidemiological Studies'.

a) Epidemiological studies
In epidemiological studies, the researchers study a large group of people and what they eat, and then have a look at the types of diseases these people suffer from. It was these epidemiological studies that first indicated that people who eat plenty of fruit and vegetables tend to develop fewer diseases of lifestyle (e.g. heart disease, cancer, etc). The researchers deduced that certain components in fruit and vegetables such as beta-carotene, and vitamins A, E, and C, were protective against these diseases.

The next step in the reasoning of scientists and vitamin manufacturers was the following: "If eating fruit and vegetables protects us against diseases, then taking the vitamins found in fruit and vegetables in pill form will do the same job."

We all know that this has lead to a tidal wave of recommendations to take vitamin supplements, and manufacturers have climbed on the bandwagon in a big way. There are literally thousands of different vitamin products available on the market today, and 'selling health, via vitamin pills' is mega-business. So convincing has the sales pitch been, that most people are convinced they can prevent the majority of diseases, or cure the diseases they already suffer from, by taking vitamin pills.

b) Meta-analyses
In this type of study, researchers go back to the scientific literature and search for studies that meet certain strict requirements (large populations, accurate measurement of outcomes, control groups, a random design, etc.) and then see what type of ultimate results can be obtained by combining the original results of all these studies.

This is what was done in the case of vitamin supplementation. A team of researchers identified 68 well conducted studies which involved more than 200 000 subjects in Europe, North and South America, Asia and Australia. The researchers then had a look at the effect of taking vitamin and some mineral supplements on the overall number of deaths in this large combined population. They found the following worrying results:

Taken alone or together with other supplements, the following supplements increased mortality signficantly:

  • Beta-carotene (the so-called 'precursor' of vitamin A which is transformed into vitamin A in the body)
  • Vitamin A
  • Vitamin E

The following supplements did NOT increase mortality (death):

  • Vitamin C
  • Selenium (a trace element)

The startling findings that taking supplements of beta-carotene, and vitamins A and E on their own, or in combination, can increase the risk of death, need to be taken very seriously. Millions of people all over the world, including in South Africa, take vitamin supplements that contain vitamins A and E and beta-carotene on a daily basis.

What should we do?
In the light of these new findings on vitamin supplements, NICUS (2007) recommends the following:

  • Ensure you are eating a balanced diet that provides all the necessary nutrients, including vitamins and minerals, that you need for good health.
  • If you think you may need additional vitamins and minerals, consult an expert, such as a dietitian or doctor.
  • Avoid taking a supplement that claims to be a 'cure-all'.
  • Don't take vitamin supplements that only contain a single nutrient (e.g. pills that only contain vitamin A, or E, or beta-carotene).
  • Have a careful look at the label of the vitamin supplement you intend taking and if you can't make out what the label means, ask the pharmacist to explain how much of each vitamin, but especially vitamins A and E and beta-carotene, the supplement contains. If the levels exceed 100% of the Recommended Daily Allowance (RDA) don't buy them. Rather use a multi-vitamin, multi-mineral supplement than one that only contains single vitamins or minerals.
  • Don't take vitamin supplements for long periods.
  • Tell your doctor if you suspect that the vitamin and/or mineral supplements you are taking are causing side-effects or making you ill.

There are exceptions to every rule and this also applies to how we are going to react to these new findings on the potential danger of using vitamin and mineral supplements. Please keep in mind the following:

People with special needs identified by a dietician or doctor will be advised to take a vitamin or mineral supplement for a specific period e.g.
- If you suffer from iron- or vitamin B12-anaemia you will need to take either iron and folic acid, or vitamin B12 supplements, until your anaemia clears up.
- If you are at risk of osteoporosis, you will need to take calcium supplements.
- If your system has been debilitated by acute illnesses or infections, your doctor or dietician may prescribe a complete vitamin and mineral supplement.
- If you are pregnant, your gynaecologist or doctor may prescribe an iron and/or folic acid supplement.
- Children below the age of 6 years in the developing world will still be given one or two high doses of vitamin A to prevent child mortality and blindness.

So please don't fall for the hype propagated by advertisements about vitamin and mineral supplements that they are 'magic bullets' that will cure or prevent every disease known to mankind. Try to obtain your vitamins and minerals from a balanced diet. Get expert help if you think you may need vitamin and mineral supplements. Don't take these supplements every day or for longer than strictly necessary. Always keep in mind that moderation is the key to good health.

- Dr Ingrid van Heerden, DietDoc, Health24, April 2007

(NICUS, 2007. Are We Oxidising Ourselves with Antioxidants? Be Careful of the Supplements You Take.

Read more:
Vitamins and minerals

Any questions? Ask DietDoc


5 reasons to love avocados

2018-10-14 07:00

Read Health24’s Comments Policy

Comment on this story
Comments have been closed for this article.