Dietary fibre, probiotics: Allies in the fight against eczema and allergies

A diet rich in fibre appears to offer some protection against atopic dermatitis (AD) and a common allergy triggered by house dust mites in Asians, with the risks further mitigated by combining dietary fibre with probiotics, as reported in a study.

In a large cohort of young Chinese adults from Singapore and Malaysia, those with high vs low dietary fibre intake (≥98.3 vs ≤69.8 g/serving/week) had much lower odds of AD (adjusted odds ratio [aOR], 0.831, 95 percent confidence interval [CI], 0.717–0.963; p<0.05) and house dust mites allergy (aOR, 0.895, 95 percent CI, 0.810–0.989; p<0.05). [Eur J Nutr 2024;64:38]

Dietary fibre intake showed no association with dry skin (aOR, 1.054, 95 percent CI, 0.898–1.237; p=0.520), suggesting that dietary fibre may not influence the xerosis associated with AD, according to the investigators.

“Low dietary fibre intake may promote mucus-degrading bacteria, increasing allergen access, while high-fibre diets support skin barrier function, effectively limiting allergen ingress and reducing sensitization risk,” they said. “High dietary fibre intake [helps] with the stabilization of gut microbial community diversity and decreases leptin levels, thus mitigating low-grade chronic inflammation.” [Cell 2016;167:1339-1353.e1321; Dermatol Pract Concept 2021;11:e2021132; Environ Microbiol 2015;17:4954-4964; Br J Nutr 2021;125:329-336]

The investigators, however, stressed that a higher dietary fibre intake alone may not sufficiently modulate immune responses and inflammation. “Probiotic supplementation may offer complementary benefits in modulating immune responses by promoting a balanced gut microbiota.” [Science 2021;374:1632-1640; Cell 2021;184:4137-4153.e14]

Indeed, among study participants who frequently consumed probiotics (once or twice per week), even moderate fibre intake showed a significant effect on AD (aOR, 0.717, 95 percent CI, 0.584–0.881; p<0.01) but not on house dust mites allergy. Meanwhile, high dietary fibre intake remained significantly associated with reduced odds of both outcomes (AD: aOR, 0.720, 95 percent CI, 0.590–0.879; p<0.01; house dust mites allergy: aOR, 0.865, 95 percent CI, 0.754–0.991; p<0.05).

Further analysis indicated that a fibre-rich diet independently mitigated risks associated with high intake of fats, saturated fats, and protein.

“Our findings primarily highlight the impact of overall dietary fibre intake on AD and house dust mites allergy outcomes, with probiotic intake being an additional, but not definitive, factor. This nuanced understanding underscores the importance of dietary fibre in managing allergic conditions, while suggesting that further research is needed to clarify the role of probiotics,” the investigators said.

Then again, the potential benefits of dietary fibre for AD management must be weighed against individual tolerance and dietary limitations, they continued. For example, certain AD patients have gastrointestinal sensitivities that can make it challenging to adopt high-fibre diets. Additionally, common food allergens such as fruits, vegetables, and legumes—all of which are rich in fibre—may restrict dietary options. [Medicina 2005;41:837-845; Nutrients 2022;14:2641; Pediatr Neonatol 2022;63:520-526]

“[Dietary fibre] should be effectively integrated into a broader dietary strategy prioritizing overall nutritional adequacy and diversity… Encouraging individuals to adopt a diet rich in fibre alongside moderation in fat and protein intake may potentially offer a practical and effective approach to reducing the risk of AD development,” the investigators said.

The study included 13,561 young Chinese adults (mean age 22.51 years, 59.4 percent female). More than half of them had healthy BMI (18.0–23.0 kg/m²: 54.9 percent) and engaged in physical activities once or twice per week (52.7 percent). The estimated average dietary fibre intake of 12.73 g/serving/day in this cohort fell below the recommended daily dietary fibre intake of 23.0 g/serving/day for a typical healthy individual in Singapore.