Food allergies may be linked to chemicals in tap water
The huge rise in food allergies may be linked to chemicals in tap water according to new research.Food allergies have risen sharply over the past 20 years, with 1-2 per cent of adults and 4-6 per cent of children thought to be affected.
The number of children admitted to hospital for food-related anaphylaxis (a life-threatening allergic reaction) has risen seven-fold since 1990 – but no one quite knows why.
The latest theory Food Allergies? Pesticides in Tap Water Might be to Blame, published in the Annals of Allergy, Asthma and Immunology, suggests that chemicals called dichlorophenols could be to blame.
US researchers who looked at food allergies in more than 2,000 people found that those with the highest levels of dichlorophenols in their urine had an 80 per cent higher risk of having a food allergy.
Their theory is that dichlorophenols, which they say are found in purified tap water and in pesticides and disinfectants, have anti-bacterial properties that could affect the microflora in the gut that are thought to protect against food allergies.
Dichlorophenols are also by-products of a common antibacterial and antifungal agent called triclosan (used in many consumer products, including toothpaste) and in the UK are more likely to be found in household cleaning products, kitchen utensils and containers and pesticide residues than in water.
Although little research has been done on UK exposure levels, the Chemicals Regulation Directorate says dichlorophenols “have not been identified as a cause of concern”.
The reason behind the rise in food and other allergies remains a mystery.
One well-known theory is the hygiene hypothesis – that as we become increasingly obsessed with cleanliness, our children are not exposed to the bugs that help the immune system develop properly.
Another unproven theory is that the rise in allergies may be due to basic changes in Western diets, with processed foods becoming more common and fresh fruit and veg less so.
Some experts now think that government guidelines introduced in the Nineties may have contributed to the explosion in food allergies.
“Parents were advised to avoid giving peanuts to young infants on the grounds that early consumption of potential allergens could affect underdeveloped immune systems, resulting in allergy – when the opposite seems to be the case,” says Prof Brostoff.
The guidelines were quietly withdrawn in 2009 after a large study the previous year showed that Jewish children living in the UK were almost 10 times more likely to develop a peanut allergy than those living in Israel, where peanut protein – often in the form of Bamba, a popular snack – is commonly given to infants in the first year of life.
Prof Brostoff says the best thing parents can do to reduce the risk of food allergy in their children is to gradually introduce potential allergens – not just peanuts, but cow’s milk, eggs and fish – at an early age.
“The lining of the gut membrane is the most powerful immune organ in the body,” he says. “The advice I always give is that it is better to introduce foods when the gut is more plastic and able to adapt. Giving a food early in a baby’s life can help make the gut more tolerant, and numerically this effect is more important than the presence in the environment of any chemicals.”
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