Herbal, 'natural' foods can harm, even kill, warn experts

Foods with herbal, traditional and 'natural' additives are believed by many to prolong life, promote alertness, even prevent cancer, without any side effects. But, cautioned experts who collected in Singapore for a conference, they can easily be dangerous, even fatal, warning that often, it is only the lack of negative statistics that keeps these products on the shelves.

While food fortification is useful in dealing with deficiencies, like that of Vitamin A, iodine and iron especially in poor and developing countries, they were not necessarily cures. ''As a result of malnutrition and imbalanced micronutrients intake worldwide, more than 190 million children are at risk of Vitamin A deficiency,'' Kenny C K Koh of pharmaceutical firm Roche Singapore Pte Ltd said.

But the addition of nutrients to food is no longer as simple as when salt was iodised in 1922 in Switzerland to prevent goitre - the enlargement of the thyroid gland due to iodine deficiency. Today, consumers are commonly bombarded with pills or health food fortified with extra, 'natural' substances to give them more energy. Some herbs or herb extracts claim to sharpen memory - like the Memory Plus tablets promoted by Vishwanath Anand in India -- and others, like betacarotene, are believed to help prevent cancer.

Experts now feel the safe amount of micronutrients to be added are yet to be determined by a simple and standard method.

David Richardson, group chief scientist of Nestle UK Ltd, said the traditional approach to estimating safe levels of vitamins and minerals for enrichment purposes was based on an ''arbitrary multiple'' of the recommended daily allowance for such substances. He said recent developments in nutrition science have drawn attention to the shortcomings of the system.

He urged caution in determining safety levels of nutrient additions, saying ''risk nutrients'' like vitamins A and D, iron, zinc, copper and phosphorus may be harmful when taken in excess. Unutilised, they stay in the body and affect its functioning instead of being excreted.

Richardson also identified vitamin C, calcium, iodine and potassium, thiamine, riboflavin and betacarotene as among ''low-risk'' nutrients that are ''known to have adverse effects (when taken) at higher levels with a relatively narrow safety margin''. Most of these are flushed out over time when they are in excess.

''There is a possibility that frequent consumption of (risk nutrients) could (increase) the risks of acute or chronic intoxication and an imbalance in nutrient supply,'' Richardson added.

The experts also warned against too much dependence on herb-based organic foods, often believed to cure a wide array of ailments. Prolonged consumption may have disastrous effects, they said.

Che Chun Tao, pharmaceutical chemist at the Hong Kong University of Science and Technology, says traditional Chinese herbs - now also found in health capsules and pills produced by western firms are not without their own dangers.

''Traditional herbs are often claimed to be relatively safe for use, but only based on short-term therapeutic applications,'' Chun said. Moreover, he said, ''Cumulative adverse effects'' may arise after extended use of some herbal products.

''There have been numerous reports that dietary supplements containing botanical ingredients have caused liver damage. Supplements containing Chinese herbs have caused life-threatening reactions in children,'' said Bruce Silverglade, legal affairs director of the US-based Centre for Science in the Public Interest. He said certain products sold as diet wonders have harmed some users. In March 1996, for instance, he said the US Food and Drug Administration issued a public warning against a health formulation called 'Diet Pep', which has caused heart attacks and hepatitis in some users.

''This product contains (the traditional Chinese herb) 'Ma Huang' and kola nut, a combination that the FDA considers dangerous,'' Silverglade said.

'Royal jelly', another popular health food, has also caught the FDA's attention. Used to ease insomnia and liver ailments, this bee extract was found to have caused ''10 serious asthma attacks'' and the death of an asthmatic girl, Silverglade said, citing a report from the Medical Journal of Australia. Royal jelly, a product used by bees to feed the growing queen, is believed to have miraculous properties by some.

Experts add that the loss or retention of some nutrients is affected by handling or certain food preparations. Iron, commonly found in meat, is sometimes ''poorly absorbed'' when eaten in combination with some cereals and vegetables.

Betacarotene had become popular among health buffs, told that it contains cancer-preventing anti-oxidants. But even this has been under re-examination in recent years, Silvergrade said.

He cited results of a 1994 study of 30,000 smokers in Finland, who took betacarotene as a supplement for five to eight years.

''This study found no reduction in the incidence of lung cancer among smokers. In fact, there was a higher incidence of lung cancer in those taking the betacarotene supplements as compared to those who took a placebo,'' he said.

In another study using betacarotene, researchers noted an ''elevated risk of lung cancer'' among the participants who were given anti-oxidant supplements.

Despite these and other findings, experts believe that micronutrients in general raise the nutritional value of food. But they say their use has to be weighed against a person's individual needs and lifestyles. In short, popping a health pill is not an instant formula for health or disease prevention.