All berry conflicting

International studies have suggested some antioxidant vitamins may shorten lifespan, now studies are telling us that antioxidants…

International studies have suggested some antioxidant vitamins may shorten lifespan, now studies are telling us that antioxidants cannot prevent ageing. PAUL GALLAGHER reports

WHETHER THEY take the form of supplements, diet pills or creams, antioxidants have been the staple of the cosmetic and health industry for many years.

Recent studies carried out on antioxidant vitamins however have questioned their benefit, with some studies concluding that some antioxidant taken in supplement form can even lead to an increased risk of mortality.

Most recently, research has also cast doubt on the idea that antioxidants have any properties at all in either reducing or preventing the ageing process.

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Antioxidants are compounds that help to protect the body from “free radicals” – highly reactive molecules capable of causing damage in the brain and other tissues. These free radicals cause oxidation in the body, analogous to rust when iron is exposed to oxygen, referred to as “oxidative stress”.

In the field of ageing research, the free radical theory has dominated the research field for more than 50 years, suggesting that ageing is primarily caused by a build-up of molecular damage as a result of oxidative stress.

Antioxidants are believed to work by “cleaning up” surplus free radicals and minimising their damage. In the cosmetics industry, this reflected in the large quantity of anti-ageing products on the market that advertise their anti-oxidant properties.

Research at proving this theory has been inconclusive, however. Recent studies carried out at University College London (UCL), using a simple nematode worm, suggests the central idea behind antioxidants playing a major part in age reduction is flawed.

Despite appearing to be a significant distance from the human species, nematode worms, used in the study, are viewed as a useful tool for researchers to get clues on long-term change as they share many genes with humans and have a lifespan measured in days.

The worms were genetically manipulated, so that their bodies would “clean up” the free radicals, just as antioxidants are believed to do.

Theoretically, this would have given them an advantage over other nematode worms in terms of ageing and lifespan. However, the genetically manipulated worms lived just as long as the normal nematode worms.

The findings, combined with the results of other recent findings using mice carried out at the Barshop Institute for longevity and ageing studies at the University of Texas, imply that the free radical theory on ageing is incorrect and that oxidative damage may not be the major factor in ageing, effectively relegating the idea that antioxidants play a part at all in reducing or preventing ageing.

Dr David Gems, from UCL’s institute of healthy ageing and genetics department, who led the research, believes we are reaching an important point in how we understand ageing.

“The fact is that we don’t understand much about the fundamentals of ageing. We know that genes and molecular cell-damage is a factor, but we don’t know what causes this damage,” he says.

“What is significant is that the oxidative or free radical theory has filled a knowledge vacuum for over 50 years, and has been the premise by which the cosmetics and diet industry have based and marketed many of their products, but there is clearly something wrong with it and it’s time to start thinking about ageing in new ways,” says Gems.

“A balanced and healthy diet is clearly beneficial for reducing the risk of many ‘old age’ diseases, such as cancer, diabetes and osteoporosis, but there is no clear evidence that eating antioxidants can slow or prevent ageing, and even less evidence to support the claims made by antioxidant pills and creams. Oxidative damage is clearly not a universal, major driver of the ageing process,” he says.

Studies carried out on antioxidant vitamins have also questioned the benefits of antioxidants in supplement form. Last April, the published findings of a review carried out at Copenhagen University Hospital in Denmark on antioxidants supplements involving 67 studies and 232,606 adult participants, suggested that antioxidants beta carotene and vitamins A and E increased the risk of death.

Other large-scale clinical trials carried out in 2000 did not support, and even questioned, the use of vitamin E and beta carotene for protection against heart disease.

And in the 1990s, clinical studies looking at whether antioxidant supplements protected smokers against lung cancer found that beta carotene actually increased cancer risk.

The Food Safety Authority of Ireland (FSAI) also points out that continuous high intakes of vitamins can cause side effects. The FSAI stresses that high intakes of the antioxidant vitamin A can cause headaches, liver damage, bone damage and birth defects, while very high doses of the antioxidant vitamin E can cause gastrointestinal distress, double vision and muscle weakness.

The benefits of antioxidants has its roots in the observation that people who eat a diet high in fruit and vegetables, such as broccoli, tomatoes and blackberries (considered rich sources of antioxidants) have lower incidence of various cancers and diseases associated with damage from oxidative stress.

Many also believe that antioxidant-rich foods includes properties that can “slow down” or “reduce” the ageing process.

What is starting to become clear, however, is that the benefits of an antioxidant-rich diet is complex, and while many people take antioxidant supplements to help them avoid having to follow a rigid antioxidant diet, researchers have found that supplements alone will not have the same effect as supplements coupled with foods rich in antioxidants.

Paula Mee, a nutritionist, says there is “no conferred” body of evidence to show that a diet of antioxidants alone can prevent ageing.

“It has been suggested that people on a diet of raw fruit and vegetables may appear to look younger, but this could be from a number of things, such as managing stress levels, not smoking and exercise.

“An antioxidant-rich diet found in a range of fruit and vegetables is clearly beneficial, but epidemiological studies where diets of fruit and veg have shown lower instances of heart disease and cancer, have included the whole package of the diet and there may be many other variables and compounds at work that we do not know yet.”

Mee also says that if people believe they are not getting enough antioxidant-rich vitamins from their daily diet, and choose to start taking supplements, then their supplement intake should be carefully regulated and should stay within 100 per cent of the recommended daily allowance (RDA).

“Large doses of antioxidant vitamins combined with an already normal and healthy diet could have unknown risks and should be avoided.

“In certain instances, it may be good for people to start taking large doses of supplements, as might be the case where someone is recovering from an illness, and antioxidant supplements used in these instances can prove beneficial, but large doses of vitamin supplements should only be taken under medical or dietetic supervision,” she adds.

Alan Ruth, a chartered biologist and chief executive of the Irish Health Trade Association (IHTA), which represents the interests of manufacturers and distributors of health store products, is critical of many recent studies on antioxidants.

“In general, conclusions on antioxidants have been drawn selectively from a very small number of recent studies, which have included ‘meta-analyses’ and ‘systematic reviews’. In most cases, the methodology used in these studies has been seriously flawed,” he says.

“There is a plethora of recent studies on antioxidants that have shown positive and beneficial results,” he says.

Ruth also believes that many of the trials carried out on antioxidants had limitations, and often included the expectation that a simple antioxidant vitamin could be expected to overturn serious illness, such as cancer or heart disease, mistakenly giving the impression that antioxidants offer a ‘magic cure’ that doesn’t exist.”

When used as part of a healthy lifestyle, antioxidants have an important and positive role to play, he says.

Des O’Carroll, president of Irish Cosmetic Association (ICA), says: “Skincare companies undertake rigorous research to ensure that product claims are backed up by robust scientific evidence.

“There are also well-documented, peer-reviewed scientific studies, conducted on human skin which clearly show how antioxidants can reduce the appearance of fine lines and wrinkles protecting cells from free radical damage by stimulating collagen production,” he adds.

While the issues surrounding the benefits of antioxidants is certain to undergo further study and debate, Mee suggests the best advice at present is to stick to the recommended five servings of fruit and vegetables per day.