is the Director and
Senior Consultant, Institute of Gastroenterology, Hepatobiliary Science &
Transplant, SRM Institutes for Medical Sciences, Chennai, Tamil Nadu. He is
also the Adjunct Professor, Yale University School of Medicine, New Haven, CT,
The following is an exclusive interview conducted by Medindia with Dr.
Q. Please explain about the microbiome to our readers?
A. Microbiome refers to a large number
of bacteria and other smaller organisms in our body. We have co-evolved with
these bacteria in our intestine over millions of years. Microbiome benefits us
in terms of nutrition, immunity, and protects us from harmful bacteria such as
the cholera or the typhoid
bacteria. These are good bacteria or probiotics in our intestine.
Q. How does microbiome play a role in different diseases in the
A. Nowadays, the intestinal bacteria are
being blamed for everything from obesity to diseases of the brain. But the
immediate connection is with gastrointestinal disorders, such as with diarrheal
diseases, fatty liver, inflammatory bowel disease. If we go beyond the gut, the
first connection is with the joints because these bacteria somehow also
influence the development of arthritis. Now there is a lot of research going on
towards what is called the gut-brain access, and the microbiome comes in
between. So it is the gut microbiome brain access, and that’s been shown to be
very important in a variety of conditions including perhaps autism and other
Q. Is the microbiota in Indians different from that of Westerners?
A. Certainly, it is the diet that
determines largely what the microbiome is. The microbiome of Indians is
different in many ways because we eat a lot more carbohydrates so we have a
preponderance of bacteria that can ferment carbohydrates. Whereas the western
diet is a very meat-based diet, you may have a predominance of what is called
the Bacteroides, which are considered to be pro-inflammatory.
Q. Does Indian diet influence microbiomes?
A. Indian diet is more
carbohydrate-rich. We still do not understand the effects of other factors.
Q. What are the nutrients that help in keeping the gut healthy?
A. In the microbiome, some bacteria are
considered good, for instance, bifidobacteria, lactobacilli. So there are some
oligosaccharides which are sugars of small chain length, which facilitate the
growth of these bacteria. There are some diets which promote the growth of
bacteroides, which is considered to be pro-inflammatory under certain
Q. Fecal transplant is being discussed – What are your current
A. The problem with fecal transplant is
that we are taking a whole concoction of the human gut bacteria, which probably
consists of more than a thousand five hundred bacterial species – some good,
some bad and some neutral and we are giving the whole concoction from one
person to another. So, fecal microbiota transplant under certain circumstances
has been beneficial for people with antibiotic-associated diarrhea or with
resistant Clostridium deficit diarrhea. These are disorders that are not
prevalent in India. While there are instances of antibiotic-associated
diarrhea, it generally stops with stopping the antibiotic and taking
probiotics. But when it becomes resistance, these are conditions which might
require a fecal transplant. It is now being used for inflammatory bowel
disease, without clear evidence that there is a benefit.
Currently, in the US, clinical trials involving fecal transplants have
been suspended because there have been severe infections in three patients and
Fecal transplants are done in India. In India, they are not
regulated. There is no uniform way of doing it. In some places, it is given as
an oral capsule or multiple oral capsules. In some places, it is provided by
spray into the large intestine. So there is a lot of heterogeneity, and there
is no regulation. At the moment, it has to be taken with caution.
Q. What is the message you want to give to our readers?
A. In a nutshell, it lies in eating a balanced diet because as long as it
has everything in balance, our microbiome is also likely to be in balance.