Sugar intake during pregnancy linked to childhood allergy, asthma

A study of almost 9000 mother-child pairs has found that high intake of sugar during pregnancy may increase the risk of allergy and allergic asthma in children.

When comparing the 20% of mothers with the highest sugar intake versus the 20% of mothers with the lowest sugar intake, there was an increased risk of 38% for allergy in the offspring (73% for allergy to two or more allergens) and 101% for allergic asthma.

Led by Queen Mary University of London (QMUL), the team used data from a world-leading birth cohort study, the Avon Longitudinal Study of Parents and Children (ALSPAC), also known as ‘Children of the 90s’. The cohort recruited mothers who were pregnant in the early 1990s and has been following up their offspring ever since.

The current study, published in the European Respiratory Journal, analysed associations between maternal intake of free sugars in pregnancy and allergy (defined by positive skin tests to common allergens, namely dust mite, cat and grass) and asthma at seven years of age. Free sugars comprise sugars (monosaccharides and disaccharides) added to foods or drinks by the manufacturer, cook or consumer, plus sugars naturally present in honey, syrups and unsweetened fruit juices. The intake of free sugars was estimated by a food frequency questionnaire in the last trimester of pregnancy.

While there was only weak evidence for a link between free sugar intake in pregnancy and asthma overall, there were strong positive associations with allergy and allergic asthma (where the child was diagnosed with asthma and had positive skin tests to allergens). Importantly, the offspring’s free sugar intake in early childhood was found to have no association with the outcomes seen in the analysis. The team found no association with eczema or hay fever.

Lead researcher Professor Seif Shaheen from QMUL’s Blizard Institute said: “We cannot say on the basis of these observations that a high intake of sugar by mothers in pregnancy is definitely causing allergy and allergic asthma in their offspring. However, given the extremely high consumption of sugar in the West, we will certainly be investigating this hypothesis further with some urgency.

“The first step is to see whether we can replicate these findings in a different cohort of mothers and children. If we can, then we will design a trial to test whether we can prevent childhood allergy and allergic asthma by reducing the consumption of sugar by mothers during pregnancy. In the meantime, we would recommend that pregnant women follow current guidelines and avoid excessive sugar consumption.”

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