Gut microbiome changes uniformly linked to allergic disease development in childhood

4th September 2023

Delays in gut microbiome maturation in young children are uniformly associated with distinct allergic diagnoses at five years of age, according to the findings of a study by Canadian researchers.

The study, which was published in the journal Nature Communications, revealed how specific gut microbiome features and early life influences are associated with children developing any of four common allergies: atopic eczema, asthma, food allergy and/or allergic rhinitis.

It is possible, therefore, that these findings could lead to methods for predicting whether a child would develop an allergic disease. They could also form the foundation of strategies to prevent them from developing, especially given that food allergies in particular continue to be a major source of life-threatening reactions in children.

Courtney Hoskinson, PhD candidate at the University of British Columbia (UBC) and the study‘s lead author said: ‘Typically, our bodies tolerate the millions of bacteria living in our guts because they do so many good things for our health. Some of the ways we tolerate them are by keeping a strong barrier between them and our immune cells and by limiting inflammatory signals that would call those immune cells into action.‘

‘We found a common breakdown in these mechanisms in babies prior to the development of allergies.‘

In the study, researchers evaluated the four clinically distinct allergic diseases diagnosed at five years of age in the large, deeply characterised CHILD cohort study. The team adopted a multi-omics approach to profile infant stool collected at study visits scheduled for ages three months and one year.

Gut microbiome and allergic diseases

The study used a deeply phenotyped cohort of 1,115 children. A total of 523 participants could be defined as a ‘healthy‘ control group in that they did not develop allergic sensitisation at any time in their life up to five years of age.

Some 592 children had been diagnosed by an expert physician at the five-year scheduled visit with one or more allergic disorders: atopic eczema (n = 367), asthma (n = 165), food allergy (n = 136) and allergic rhinitis (n = 187). There were gut microbiome features uniformly associated with these allergic diagnoses at five years of age.

When evaluating the association between early-life factors and a diagnosis of allergic disease at age five, male sex, a history of either maternal of paternal atopy and antibiotic usage before age one were all significantly linked with an increased risk of developing an allergic disease.

In contrast, breastfeeding up to age six months and self-identifying as Caucasian were negatively associated with an allergy diagnosis.

Dr Stuart Turvey, professor in the department of pediatrics at UBC, investigator at British Columbia Children‘s Hospital Research Institute and co-senior author on the study, added: ‘There are a lot of potential insights from this robust analysis. From these data we can see that factors such as antibiotic usage in the first year of life are more likely to result in later allergic disorders, while breastfeeding for the first six months is protective. This was universal to all the allergic disorders we studied.

‘Developing therapies that change these interactions during infancy may therefore prevent the development of all sorts of allergic diseases in childhood, which often last a lifetime.‘

‘Social jetlag’ resulting from irregular sleep patterns associated with harmful gut bacteria

8th August 2023

Irregular sleep patterns, caused by ‘social jetlag’ – the shift in a person’s internal body clock when sleeping patterns change between workdays and free days – are associated with harmful gut bacteria and adverse health outcomes, according to a new study.

Undertaken by King’s College London (KCL) and published in the European Journal of Nutrition, the study was designed to explore the relationship between social jetlag and gut microbial composition, diet and cardiometabolic health.

It found that social jetlag is associated with unfavourable diet quality, including a higher intake of potatoes and sugar-sweetened beverages and lower intakes of fruits and nuts, together with slightly higher markers of inflammation, compared to those without social jetlag.

The researchers used information from the ZOE PREDICT 1 study, which includes data from 1,002 monozygotic, dizygotic and non-twin healthy UK individuals aged 18-65 years.

The team assessed demographic, diet, cardiometabolic, stool metagenomics and postprandial metabolic measures. Sleep patterns were self-reported and used to calculate social jetlag. This was deemed to be a 90-minute difference in the timing of the midpoint of sleep – the halfway point between when a person goes to sleep and when they wake up – on weekdays versus weekend days.

The team also collected blood samples following the consumption of a standardised meal consisting of two high-fat muffins and a milkshake.

Social jetlag and the gut microbiome

A total of 934 individuals were included in the analysis and 145 were defined as having social jetlag and the others had a routine sleep schedule. All participants were healthy and lean, and slept for over seven hours a night throughout the week.

In an analysis of their gut microbiomes, three out of six microbiota species linked to ‘unfavourable’ health outcomes were more abundant in the social jet lag group. These microbes are associated with poor diet quality and are indicators of obesity and cardiometabolic health, and create markers in the blood related to higher levels of inflammation.

Senior author for the study Wendy Hall, said: ‘We know that major disruptions in sleep, such as shift work, can have a profound impact on your health. This is the first study to show that even small differences in sleep timings across the week seems to be linked to differences in gut bacterial species.

‘Some of these associations were linked to dietary differences, but our data also indicates that other, as yet unknown, factors may be involved. We need intervention trials to find out whether improving sleep time consistency can lead to beneficial changes in the gut microbiome and related health outcomes.‘

The gut microbiome refers to the community of bacterial species within the intestines and plays an important role in the overall health of the host. In fact, the microbiome can be easily disturbed, for instance after taking antibiotics, although taking a probiotic yogurt appears to restore the antibiotic-induced disturbance.