Mounting evidence suggests microorganisms that line our digestive tracts – called the gut microbiota – may be the key to preventing allergies. Children's immune systems today have become 'disturbed' and sometimes 'hyper-active' to the environment and parents are finding it harder and harder to navigate through the minefield of potentially dangerous and unknown triggers. It is a source of tremendous emotional and social distresses.
Fortunately, numerous studies in recent years have tied exposure to beneficial gut microbiota to a host of positive health effects including the prevention of atopic diseases (i.e. eczema, allergic rhinitis and asthma). Could manipulation of our gut microbiota be the answer to preventing allergies once and for all?
The Rise of Allergies
Atopic diseases have increased in frequency in recent decades and now affect approximately 20% of the population in developing countries. The disease has a profound impact on the quality of life, social relationships, development and may interfere with a child's school and physical activities.
According to Consultant Gastroenterologist, Associate Professor Dr Raja Affendi Raja Ali, "the increase in prevalence of atopic diseases in a relatively short period of time, can potentially rules out genetic elements as the dominant factor". Instead, he adds, "lifestyle patterns, dietary habits, and environmental pollution, or in other words 'exposome factors' could be reasons why places like Malaysia is experiencing a spike in incidence of auto-immune related conditions such as asthma and allergies".
What is Gut Microbiome?
The gut microbiome is the collective genomes of bacteria, archaea, viruses and other microbes that reside in out intestine. They contribute to metabolism (e.g. digestion, making nutrients), protect against pathogens, and regulate some parts of the immune system.
More than 100 trillion microbes call our gut home, they constitute 90% of the total number of cells associated with our bodies. This shows just how significant these microbes are to us. Understanding more about interaction between our gut microbiome and host could help us unlock therapies to improve human health.
Assoc Prof Dr Raja Affendi, who is also the Head of Gastroenterology & Hepatology Unit at Hospital Universiti Kebangsaan Malaysia (HUKM) explains that, "our gut microbiome plays an important part in human health and disease, there is an intricate link between these tiny life-forms and how it affects our body". Prof Raja Affendi is currently exploring these links in an experiment to investigate the effects of lactobacillus-based cultured milk drink among patients with irritable bowel syndrome who have problem with constipation.
Link to Allergy
One area of health that has garnered significant interest is the role of gut microbiome in allergy prevention. Researchers found that the disruption of gut microbiome by factors such as birth by C-section, breastfeeding, introduction of solid foods, and use of antibiotics by the mother or infant, increased atopic disease incidence. Similarly, scientists have found that babies with fewer gut microbial diversity had a higher risk of developing allergies as infants.
The microbiome of the gut helps regulate the activities of important allergy-associated immune cells. They work by producing molecules capable of stimulating the production of protective immune cells against allergy early in infancy.
One of the most studied microbe in the area of allergy prevention is the bacteria Lactobacillus sp. In one study, Lactobacillus was given before and after pregnancy to mothers with a family history of allergy or asthma. Results indicated a promising effect on the prevention of atopic disease. Similarly, Lactobacillus strains were tested on children with eczema which revealed a moderate improvement in the clinical severity of eczema and a randomised, double-blind study found that Lactobacillus was able to significantly prevent eczema in children below the age of two.
Diversifying Gut Microbiome
The gut microbiome hosts up to 1000 bacterial species that encode about 5 million genes which perform many of the functions required for host physiology and survival. To promote the growth of good gut microbiota and diversify the gut microbiome, you should:
Eat more prebiotics
Prebiotics are non-digestible food ingredients that can stimulate the growth of bacteria in the gut, thus, help improve our health. Prebiotics occur naturally in foods such as leeks, asparagus, chicory, Jerusalem artichokes, garlic, onions, wheat, oats, and soybeans.
Supplement with probiotics
Probiotics are able to replenish the gut with certain strains of bacteria (e.g. Lactobacillus and Bifidobacteria) which confer health benefits when present in adequate amounts. Probiotics are normally consumed in fermented foods with active live cultures (e.g. kimchi, tempeh, yogurt, sauerkraut, aged cheese, kefir, cultured milk drinks).
Physical exercise promotes microbiome diversity (which is associated with a healthier state) and increases beneficial gut bacteria populations. The Malaysian Physical Activity Pyramid recommends 60 minutes of moderate intensity exercise most days of the week followed by reducing sedentary behaviour.
The gut microbiome plays an important role in immune function and needs to be properly balanced and nourished if you want to maintain good overall health. Allergies tend to start from young and manifest as a person gets older. Fortunately, as we learn more about gut microbiota functions, specifically its relationship to allergy, we could be able to one day, develop a strategy to manipulate gut microbiome to prevent or treat various atopic diseases.