ARE THOSE FOOD SUPPLEMENTS SAFE?

 The European Food Safety Agency defines food supplements as concentrated sources of nutrients or other substances (like vitamins, minerals and amino acids) with a nutritional or physiological effect.

Their use is justified among people with poor nutrition or digestive illness, but controversy arises when anyone with normal nutritional intake uses them over the long term. 

Health authorities, especially in Europe, are reviewing the legislation there. Lax regulatory constraint in most countries benefits supplements, so state officials often intervene when doctors or the news media report side effects.

The claims made for diet supplements are based on a pharmacological reasoning that is often extrapolated to some clinical benefit. The blood marker homocysteine, for example, is increased among people who have a shortage of Vitamin B6 or suffer from chronic inflammation commonly found in cardiovascular diseases and malignant tumours. When Vitamin B6 is administered, the blood level of homocysteine tends to decrease. 

From this mere “blood testing” observation, promoters of Vitamin B6 avow that it makes a wonderful diet supplement, preventing and treating cardiovascular diseases and cancers. Such statements, however, need to be validated by clinical human trials. 

The main issue regarding diet supplements is that the law doesn’t require their efficacy and safety to be proved before such claims are made.

Several medical institutions recently unveiled the results of large clinical tests of the long-term effects of supplements. A five-year French study involving 2,500 people found no benefit in the prevention of cardiac events between one group given placebos and others given a B vitamin complex and/or Omega 3. 

It’s more worrying when other reliable trials reveal harmful effects. A study in Canada found that excess iron could affect liver function, and that too much Vitamin A or E intake significantly increased the risk of lung or prostate cancer. 

In another assessment involving 60,000 women, the regular intake of betacaroten as a diet supplement was associated with increased risk of cancer among female smokers.

It must be stressed that supplements can't replicate all the benefits of whole foods like vegetables and fruit, which offer much greater nutritional value thanks to their variety of micro-nutrients. 

Whole foods also provide essential fibre to facilitate digestion and contain protective substances such as phytochemicals and natural anti-oxidants.

Most scientific studies have reached the same conclusion: People of normal health gain no substantial benefit from the regular use of supplements, and in some cases add to their risk of falling ill. 

The well-regarded Mayo Clinic in the US recommends periodically checking the website of that country’s Food and Drug Administration for updates on supplement side effects.

 

Dr Gerard Lalande is managing director of CEO-Health, which provides medical referrals for expatriates and customised executive medical check-ups in Thailand. He can be contacted at gerard.lalande@ceo-health.com.