High maternal sugar intake during pregnancy may increase the risk of allergy and allergic asthma in the offspring, according to an early study led by Queen Mary University of London (QMUL) involving almost 9,000 mother-child pairs.
While some research has reported an association between a high consumption of sugar-containing beverages and asthma in children, the relation between maternal sugar intake during pregnancy and allergy and asthma in the offspring has been little studied.
The team, which included researchers from University of Bristol, 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, which is 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.
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).
When comparing the 20 per cent of mothers with the highest sugar intake versus the 20 per cent of mothers with the lowest sugar intake, there was an increased risk of 38 per cent for allergy in the offspring (73 per cent for allergy to two or more allergens) and 101 per cent for allergic asthma. The team found no association with eczema or hay fever.
Lead researcher Professor Seif Shaheen from QMUL 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."
The team speculate that the associations may be explained by a high maternal intake of fructose causing a persistent postnatal allergic immune response leading to allergic inflammation in the developing lung.
The researchers controlled for numerous potential confounders in their analyses, such as background maternal characteristics, social factors and other aspects of maternal diet, including foods and nutrients that have been previously linked to childhood asthma and allergy.
Importantly, the offspring's free sugar intake in early childhood was found to have no association with the outcomes seen in the analysis.
As the study is observational, it does not prove a causal link between maternal sugar intake and allergies or asthma. A randomised controlled trial would be needed to definitively test causality.
The study was funded by a European Respiratory Society long-term fellowship.
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Notes to the editor
- Free sugars comprise sugars (monosaccharides and disaccharides) added to foods or drinks by the manufacturer, cook, or consumer, and 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.
- Research paper: 'Maternal intake of sugar during pregnancy and childhood respiratory and atopic outcomes'. Annabelle Bédard, Kate Northstone, A John Henderson, Seif O Shaheen. European Respiratory Journal.
Available here once embargo lifts: http://erj.ersjournals.com/lookup/doi/10.1183/13993003.00073-2017
About Queen Mary University of London
Queen Mary University of London (QMUL) is one of the UK's leading universities, and one of the largest institutions in the University of London, with 21,187 students from more than 155 countries.
A member of the Russell Group, we work across the humanities and social sciences, medicine and dentistry, and science and engineering, with inspirational teaching directly informed by our research. In the most recent national assessment of the quality of research, we were placed ninth in the UK (REF 2014).
As well as our main site at Mile End - which is home to one of the largest self-contained residential campuses in London - we have campuses at Whitechapel, Charterhouse Square, and West Smithfield dedicated to the study of medicine, and a base for legal studies at Lincoln's Inn Fields.
We have a rich history in London with roots in Europe's first public hospital, St Barts; England's first medical school, The London; one of the first colleges to provide higher education to women, Westfield College; and the Victorian philanthropic project, the People's Palace at Mile End.
Today, as well as retaining these close connections to our local community, we are known for our international collaborations in both teaching and research.
QMUL has an annual turnover of £350m, a research income worth £125m (2014/15), and generates employment and output worth £700m to the UK economy each year.
Children of the 90s
Based at the University of Bristol, Children of the 90s, also known as the Avon Longitudinal Study of Parents and Children (ALSPAC), is a long-term health-research project that enrolled more than 14,000 pregnant women in 1991 and 1992. It has been following the health and development of the parents and their children in detail ever since and is currently recruiting the children and the siblings of the original children into the study. It receives core funding from the Medical Research Council, the Wellcome Trust and the University of Bristol. Find out more at http://www.childrenofthe90s.ac.uk
European Respiratory Journal