Rise in Incidence of Allergy
The rise in the incidence of allergic disease in affluent countries over the last 20 to 30 years has been attributed to lifestyle factors. Similar increases in the prevalence of allergy are being seen in developing countries as Western dietary and lifestyle habits are adopted.

Lifestyle

Some experts believe that the lifestyle factors associated with the development of allergy are related to hygiene. That is to say that living in a really clean and hygienic house with reduced exposure to microbes increases the risk of developing allergy. Several studies and observations support this theory. For example, the incidence of allergy is higher in firstborn children than second or third children. This is because the second and third children are exposed to more bugs, introduced to them by the first child from playschool, nursery or school. Another fact that supports this idea is that children born on farms, where hygiene standards will differ from an urban household, are less likely to suffer from allergy.

Genetics

Lifestyle, however, does not explain everything. For example, most newborns are sensitised to allergens while in the womb. However, not all babies go on to develop allergy. Genetics provide a possible explanation why some children develop allergy while others do not. If a baby inherits allergy-linked genes from its mother, it is four to five times more likely to develop food allergy or eczema by age one than if it inherits allergy-linked genes from its father.

Functional Foods

Understanding allergy is difficult, to say the least, and many theories and hypotheses offer small amounts of information that help to give clarity to the overall picture. A new area of research with promising results is the possible beneficial effect of certain functional foods on allergy. The functional food in question is the probiotic LGG. It is now added to some brands of milk and yoghurt (e.g. Avonmore LGG milk, Danone yoghurt).

A recent study looked at whether the development of allergic disease can be prevented in early infancy by giving probiotic bacteria to pregnant mothers four weeks before they gave birth and during breastfeeding until their baby reached six months. The babies were all from families where there was a history of allergic disease. The infants were assessed up to the age of two to see if they would develop eczema. The mothers and babies in this study were assigned to take an LGG probiotic or a placebo. Neither group knew whether they were taking the probiotic or the placebo. This is known as a blind study and it is considered to be the most reliable way to conduct research of this nature.

The results showed that although some children in both groups developed eczema (this would be expected because their parents had a history of allergy, making them much more likely to develop allergy), there were differences in the incidence of eczema. In fact, there was a significant difference in the numbers in each group who developed eczema. LGG conferred a significant protective effect; whereas 47% of children receiving the placebo developed eczema, only 15% of the children taking the probiotic developed the condition.

Many more studies of this nature are needed before the research could be described as conclusive. However, the results are very promising. Eating foods with probiotic LGG is an easy step for pregnant women to take, as these foods are widely available in supermarkets and are nourishing too. LGG milk and yoghurts will also contribute to calcium needs, which increase by 50% in the second half of pregnancy.

Recommendations

Probiotics are safe to eat during pregnancy and although their beneficial effect in reducing the risk of eczema remains to be proven, the potential benefits to babies born to mothers who themselves have an allergy may indeed be very worthwhile.