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A Friendly Force

Research on benign effects of bacteria on nutrition has policy implications.

Written by K Srinath Reddy | Published: April 8, 2016 12:00 am
bacteria, research, bacteria on nutrition, bacteria research, malnutrition, malnutrition in children, children malnutrition, india express The gut microbiome, in particular, has been linked to nutrition and immunity.

One of the major revelations of life science research in the past decade has been the recognition that the trillions of bacteria that reside in our gut, and in other parts of our body, share a mutually dependent bond with us. The gut microbiome, in particular, has been linked to nutrition and immunity. Disturbances in this friendly force have been related to an increased susceptibility for several health disorders.

Truly, human physiology can no longer consider itself distinctively separate from the microbiome that resides as a collective colony within us. While the specific composition of the microbiome varies from person to person and changes over life, associations of different microbiome profiles are now being associated with health or disease across populations.

Recently published scientific studies have thrown light on the role of the microbiome in childhood malnutrition and also provide a link to malnutrition in the mother. These studies, conducted by researchers in Bangladesh, Malawi, France and the US, were published in February this year, in leading international journals, Science and Cell. The animal models employed were mice and piglets, while young children and lactating mothers provided the human link.

The studies were stimulated by an observation that germ-free mice do not grow well. What about humans? This question led the scientists to compare the microbiomes of poorly nourished and well-nourished infants and young children. Gut microbiomes were isolated from fecal samples of malnourished and healthy children. The microbiome was “immature” and less diverse in malnourished children compared to the better developed “mature microbiome” found in healthy children of the same age.

When the immature microbiome from malnourished children was introduced with food into specially bred “germ free” mice, they failed to thrive and had impaired growth. When similar mice received the mature microbiome from healthy children, while being fed an identical diet, they had good muscle and bone growth. When the malnourished mice subsequently received the mature microbiome from the healthy mice, good growth was restored in them.

The mechanism by which the friendly bacteria help child growth is still to be elucidated, but it appears that they may influence the activity of growth hormones produced in the human body. The growth of brain, liver, muscle and bones are thereby affected by changes in the microbiome. Interestingly, other studies have implicated the microbiome in the development of obesity.

How is the microbiome of the young infant shaped? Passage through the natural birth passage of the mother provides the first gift of protective bacteria, something which babies born through Caesarean section would not receive. Immediately thereafter, mother’s milk seems to provide the stimulus for the growth and maturation of the infant’s microbiome. Studies of the chemical composition of mothers’ milk have shown the presence of a modified sugar (sialylated oligosaccharides). This is not utilised by the baby for its own nutrition.

However, the bacteria constituting the infant’s microbiome thrive on this sugar which serves as their food. Malnourished mothers have low levels of this sugar in their milk. Consequently, the microbiomes of their infants fail to mature. That, in turn, leads to malnourished babies. Malnutrition begets malnutrition, not just in one human baby but in trillions of living forms!

Giving these oligosaccharides to malnourished young mice or piglets helps improve their growth, suggesting a potential pathway to remediation in malnourished children with immature microbiomes.

Mother Nature offers us some big lessons through this fresh glimpse of its operation. First, mother’s milk is highly protective, yet another reminder that there is really no substitute. Second, multiple life forms are highly interdependent; some of the lowly and much derided bacteria are essential allies for health throughout our life course. Third, malnutrition in children may have several causes but one preventable cause that must be addressed with urgency is the prevention of malnutrition in mothers. This must begin from the time the future mother is a girl child but particular attention must be paid to the period of pregnancy. Finally, as more of the mysteries of life are opened up by modern science, we must regard nature with both awe and humility.


The writer is president, Public Health Foundation of India

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  1. K
    Apr 8, 2016 at 8:02 am
    Nature has numerous life forms to help us. It is for us to utilise them for the welfare of humanity.
    1. D
      Apr 8, 2016 at 8:23 pm
      Brilliant study and nicely drawn conclusions by Mr Reddy. Indian wisdom puts cow's milk as second best after mother's for infants and it has been recommended since ages especially in case of lactation failure or if mother is unable to feed due to any reason. The presence of oligosaccharides must be studied in cow's milk (Indian breeds). Secondly, nowadays doctors are promoting C-section to expectant mothers for monetary gains but people must be sensitized about why it will ultimately impact the gut-health of subsequently born child. lt;br/gt;Kudos to the author for publishing these invaluable insights!!
      1. D
        Apr 8, 2016 at 7:07 am
        "we must regard nature with both awe and humility." And reverence perhaps.
        1. R
          Apr 8, 2016 at 5:42 am
          Interesting article. However, there is one aspect which is missing in this analysis. In the Western world, most babies are weaned away from mother's milk at a fairly average age. Westeners often say they see no difference in development of kids who had mother's milk and those who did not. The article takes the position that most health related professionals have taken in India - mother's milk is the best. The article also reaches the same conclusion. It would be interesting to compare nutritional and other development status of children, from income groups who can afford good nutrition, when they are raised on mother's milk and on other foods.