You hear about them all the time, and countless foods and supplements containing them are peddled with promises that they’ll fix you up, keep you healthy, and put a little extra spring in your step.
But do antioxidants really fulfill all that hype? Or can filling up on them actually be harmful to your health?
A new cautionary note has been sounded in a study from scientists in Britain and the Netherlands, and our post includes the announcements from their respective universities.
First, from Maastricht University:
Researchers Professor Pietro Ghezzi of the Brighton and Sussex Medical School and Professor Harald Schmidt of Maastricht University urge caution in the use of antioxidants. Many people take antioxidants to treat or prevent disease. Ghezzi and Schmidt’s research has shown that such supplements help only in clear cases of vitamin deficiency, and that some antioxidants may even have harmful effects. The study has been published in the British Journal of Pharmacology.
The scientists investigated the benefits of antioxidant use in preventing or curing illness and came to the conclusion that ingesting these substances has no benefits. They prove beneficial only in cases where there is an established vitamin deficiency.
Professor Ghezzi explains, ‘Many people assume that taking antioxidants is good for them. Our research shows that this is only the case when an individual has been diagnosed with an obvious vitamin deficiency’.
No study to date has ever shown any benefits from antioxidants. On the contrary, some antioxidants are even harmful. This is because when antioxidants are ingested, the oxygen molecules affect not only disease but also the body’s immune system and ability to synthesise certain hormones; these effects may be harmful and have negative consequences that outweigh the good.
‘Nevertheless’, says Professor Schmidt, ‘oxidative stress can be valuable in treating disease under certain conditions. But that would entail the use of traditional medicines rather than antioxidants to treat the illness, since they attack only the sources of the oxygen molecules that are causing the disease in question, while leaving sources of healthy oxygen molecules unaffected’.
Our bodies need oxygen. Yet that same oxygen can also be the cause of oxidative stress and disease. Oxidative stress is a metabolic condition in which a greater number of reactive oxygen bonds are released than usual. It may be the result of factors such as excessive alcohol consumption, smoking, medicine use, physical or psychological stress, prolonged sun exposure, air pollution, intensive exercise or being overweight. To compensate for the effect, many people take antioxidants as a dietary supplement.
The study findings have been published in the British Journal of Pharmacology. [open access].
And from the Brighton and Sussex Medical School:
The lay press and thousands of nutritional products warn of oxygen radicals or oxidative stress and recommend taking so-called antioxidants to prevent or treat illness. Professor Pietro Ghezzi at BSMS and Professor Harald Schmidt at the University of Maastricht have analysed the evidence behind this and concluded that there are no demonstrated benefits to taking these supplements.
There’s more, after the jump. . .
Life depends on oxygen to produce energy for our body. The oxygen has also the potential to generate so-called oxygen radicals, which may cause “oxidative stress” and disease. Markers of oxidative stress have been correlated with cardiovascular disease, cancer, and diabetes. Because of these associations, antioxidant supplements are taken by millions of people.
Professor Ghezzi said: “A lot of people assume antioxidants will only do them good, but they can actually be doing harm. Our review shows that to be safe, you should only take these if you have been diagnosed with a clear vitamin deficiency.”
“Randomised clinical trials testing antioxidants have not shown conclusive evidence for any benefit. On the contrary, some antioxidants may have a harmful effect. This is due to the fact that oxygen radicals are not only triggers of disease, but have many important functions in our body, such as the immune defence and hormone synthesis. Thus antioxidants will always interfere with both healthy and potential disease-triggering oxygen molecules. The net effect is therefore zero or apparently even negative.”
Professor Schmidt said: “Nevertheless, oxidative stress could be important in some conditions and in a small proportion of patients. However it can be managed in a totally different manner, with classical drugs targeted only at those sources of oxygen molecules that are triggers of disease and leaving the healthy ones alone.”
One thing antioxidants are definitively good for is the corporate bottom line, with sales of supplements topping $5.6 billion in 2012, and certainly much larger by now.