The rates of food allergy in Singapore and Asia are generally lower than in the West, with the exception of shellfish allergy. Genetics explains this in part; however, children of migrant parents tend to adopt the allergic characteristics profile of their newly adopted country, suggesting a strong environmental influence. These environmental risk factors include alterations in the environmental microbiota (hygiene hypothesis), changes in nutritional patterns and a rich sedentary lifestyle, which possibly influence epigenetic mechanisms pre- or perinatally in a dynamic (epi)genetic-environmental interplay.

Prenatally, the consumption of probiotics in pregnancy has some impact on prevention of allergic diseases such as eczema, but evidence for the prevention of food allergy is still lacking. In addition, there is increasing evidence that higher intake of peanut, milk and wheat during pregnancy is associated with reduced allergic diseases, including food allergy in mid-childhood.

Postnatally, although there is no good evidence to show that breastfeeding is protective for allergies, breast milk is still recommended in high-risk allergic infants because of its immunoprotective properties, as well as its numerous other health benefits for infants. However, there is evidence for the use of hydrolysed formulas in preventing food allergies in infants who cannot be completely breast milk-fed. A study from Singapore has shown that consuming probiotics in the first six months of life does not impact allergic outcomes.

The timing of introduction of complementary solids in infancy is a persistent source of contention in allergy prevention. It is possible that despite rapid urbanisation in Singapore, maintenance of traditional dietary practices such as early introduction of egg and fish in rice porridge, and peanut in soups may have contributed to the low rates of food allergy. This would be in keeping with current knowledge and theories that early consumption of peanut and egg may prevent food allergy. Another interesting practice observed in Singapore is that many community doctors still advise that egg be introduced by one year of age, or even reintroduced if there is a history of mild egg allergy before the uptake of the measles, mumps and rubella (MMR) vaccine. This is due to the lack of knowledge that MMR is safe in egg-allergic children, even those with anaphylaxis to egg. Nonetheless, in terms of early introduction, it would account for the preliminary finding that 80.5% of this cohort had been introduced egg of any form by the age of 12 months (Lee AJ, unpublished), and may even have contributed to the low rates of egg allergy in Singapore.

Since 2010, local clinical practice guidelines in the manage-ment of food allergy have recommended the introduction of semi-solid foods at 4–6 months, and to avoid delay beyond six months even in high-risk atopic children. However, preliminary findings show that the median age of weaning in Singapore is 6 (range 1–24) months. Many physicians in Singapore still advise weaning at six months in accordance with the guidelines of World Health Organization, whose recommendations also cater to more underdeveloped countries. There is no evidence that delayed weaning beyond six months is protective for allergic diseases and food allergy; however, data from ongoing placebo controlled trials in high-risk cohorts are still pending, and would be needed in order to finalise local guidelines on weaning practices to prevent allergic diseases.

In conclusion, with the exception of shellfish, overall food allergy rates in Singapore continue to be low and non-epidemic, unlike in highly industrialised nations. Peanut is an increasingly common life-threatening allergen, and together with unique allergies such as GOS, should always be observed for. More studies analysing weaning and lifestyle practices, particularly with respect to food allergy prevention, are necessary in order to maintain this low prevalence in Singapore.


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