Breast milk goes a long way to setting up healthy immune systems for life, new research shows. Image Credit: iStock

Breast is best, new mothers are routinely told, an adage that emphasises the importance of mother’s milk in children’s development. Recent research bears that out, with scientists underscoring the role of breastfeeding in building healthy bacterial colonies in our digestive systems.

A team of researchers from Newcastle University recently established that breast milk is the most significant factor associated with establishing the gastrointestinal microbiome. As humans, we host several collections of microorganisms and their genetic material at various sites around our bodies, from the cornea to the lungs, with the most important sited in the alimentary canal. This gut microbiome, which can weigh up to two kilos per person, controls our digestion and benefits the immune system, among other areas, and its imbalance has been linked to weight gain, high blood sugar, high cholesterol and other disorders.

As an adult, while you can’t undo the past, there are certainly things you can do to improve the health of your gut.

- Dr Michael Ruscio, Author, Healthy Gut, Healthy You

The new study, published in the journal Nature in October, shows that a child has until the age of two-and-a-half to establish healthy gut bacteria — with little change after this point.

“Breastfeeding has long been understood to be good for infants and epidemiological evidence shows being breastfed early in life is associated with lower risk of many later life diseases, such as allergy and obesity,” said Dr Christopher Stewart from Newcastle University’s Institute of Cellular Medicine. He co-led the research, which used a group of patients involved in the ongoing multinational TEDDY (The Environmental Determinants of Diabetes in the Young) study.

Breast milk contains Bifidobacterium, one of the major bacterial groups in the human gastrointestinal tract, and a key component of probiotics because of their therapeutic properties. Once infants are weaned, the Newcastle research revealed, the composition of our intestinal bacteria is rapidly altered and appears to remain constant over our adult lives. “Remarkably, from this point on, the microbiome progressed quickly towards being stable, where the bacteria in the gut will potentially remain for the rest of that individual’s life,” said Dr Stewart.

The question here is whether or not this bacterial profile can be changed in later life, and what needs to be done.

“It is essentially true that we see a trend in the literature that early life factors occurring up to two to three years of age seem to have a long-term impact on the microbiota and certain immune and inflammatory diseases (such as allergies, asthma, and atopic dermatitis),” says Dr Michael Ruscio, a California-based functional medicine practitioner and the bestselling author of Healthy Gut, Healthy You, which posits that most ailments can be healed by balancing the gut microbiome.

If children are not exposed to all kinds of bugs early in life, their immune system development remains incomplete.

- Nishi Singh, Dubai Higher Colleges of Technology

“Early-life factors like C-sections, not being breastfed, antibiotic use, and where someone lives seem to be the most tightly correlated with long-term effects,” he tells Better Health. “This development influences the formation of the immune system, and both of these tend to have more of a long-term impact during that formative window.”

His view is that while the research shows that the broad structure of the microbiome is fixed early on, it can be altered — and balanced — later in life.

“The important thing to mention is that as an adult, while you can’t undo the past, there are certainly things you can do to improve the health of your gut,” he says. “There really are a wealth of modifiable factors that can influence someone’s symptoms and health outcomes. Just because your genetics and your early-life history aren’t modifiable, doesn’t mean you can’t be healthy and you can’t feel well, as many interventions can generally trump the impact of genetics and early-life factors.”

For starters, cut out sugar, artificial sweeteners, processed fats and emulsifiers. Many of these are in highly processed junk food, which is lethal for alimentary bacteria. For example, Tim Spector, Professor of Genetic Epidemiology at King’s College London and Director of the British Gut Microbiome Project, explains how he put his son on a fast-food diet of chicken nuggets, burgers and soft drinks. After ten days, the boy lost 40 per cent of his microbe species and reported feeling sick and lethargic, Spector says in an introduction to The Healthy Gut Handbook by Justin Pattison. Emulsifiers help maintain the texture of junk food, but produce abnormal chemicals in the gut, which are believed to lead to weight gain and spur the onset of diabetes.

“Emulsifiers might be particularly problematic because they may damage the lining of the gut, thus causing a ‘leaky gut’, which is one antecedent for autoimmune conditions,” Dr Ruscio says.

After breastfeeding

He recommends that children be breastfed for as long as possible. As they grow into toddlers, they must be allowed to play outside and in the dirt, and they shouldn’t be “over-washed”. In other words, don’t be excessively concerned about hygiene.

“Bringing up children in sterile environments robs them of the opportunity to be exposed to the microbes that are necessary to educate their developing immune system in the crucial first few years of life,” explains Dr Nishi Singh, Consultant Medical Microbiologist-Virologist and former Chair, Health Sciences at the Dubai Higher Colleges of Technology. The thymus, the immune gland that performs this function of training the immune system, produces T-lymphocytes or T cells, a kind of white blood cell that protects the body from threats such as viruses and infections. Genetic mutations can turn some of these T-cells rogue, so that they do not differentiate between invaders and the body’s own cells, and begin attacking healthy tissues. In serious cases, this leads to autoimmune diseases such as type 1 diabetes, arthritis, allergies and more. “If children are not exposed to all kinds of bugs early in life, their immune system development remains incomplete,” Dr Singh explains.

She advocates a rough-and-tumble childhood, with exposure to as many different stimuli as possible. “Children growing up in a ‘normal’ environment with siblings, outdoor play, and household pets are exposed to a variety of bugs, and these, along with natural practises like breastfeeding with the right nutrients, allows all the right families of microbes to become a part of their microbiome. The relative proportions of different families determine health. For a child growing in sterile environment, this opportunity is lost. So mothers in UAE, do let the child eat that cookie off the floor and give your child the opportunity to grow with a healthy microbiome.”

In other words, the five-second rule applies — within reason.