Food For Thought- Kimchi With Kefir

“LONG LIVE LIFE! — DOCTOR METCHNIKOFF AND THE STRUGGLE AGAINST DEATH”

“NONE OF US SHOULD DESPAIR TO SEE THE YEAR 2000! WE’LL REACH THE AGE OF THE PATRIARCHS, AND MONSIEUR METCHNIKOFF WILL BE DAMNED ONLY BY HEIRS TO FORTUNES !!!”

Headlines such as these shook the world in the early 1900s, as the scientific community was waking up to the beneficial roles of microscopic creatures in our gut. Despite these early reports of the beneficial effects of gut microbiota in human health, the topic got side-lined and was overlooked for a long time. It was only in the 1990’s that there was a renewed interest in the field, and today we have accumulated a wealth of knowledge about the beneficial roles of gut microbiota such as regulating its host’s nutrient metabolism and producing neurotransmitters and neurohormones. The study of gut microbiota can be dated back to Elie Metchnikoff who rose to fame, and was awarded the Nobel Prize in 1908, for his discovery of phagocytes, an important player of the immune system.

Metchnikoff postulated that humans with longer large intestines had shorter lifespans. Since intestines are host to microbes that release toxic compounds, Metchnikoff reasoned that these microbes could have been useful to us when our ancestors consumed raw food, but now they caused more harm as the consumption of cooked food has rendered their ‘services’ unnecessary. In the 1880’s Louis Pasteur was playing around with the idea that microbes living inside us had health benefits. This inspired the Russian zoologist, Metchnikoff to take Pasteur’s ideas forward with renewed vigor. Metchnikoff studied the various components of fermented milk and concluded that one of its ingredients, lactic acid, a by-product of Lactobacillus, prevented the growth of harmful bacteria, thus limiting the release of toxins. For this reason, he recommended consuming fermented milk for health benefits, a diet that became very popular in his time.

Research into the effects of microbes residing within our gut has moved forward rapidly and now we have investigative tools Pasteur or Metchnikoff would have never dreamed of. The scientific community is now well aware of the effects of gut microbiota on physical and psychological health. Recent decades have seen scientists focussing on the interplay between the gut and the brain. Although the digestive and nervous systems have distinct roles in the human body, the gut and the brain are constantly engaged in a complex dance that is often referred to as the ‘gut-brain axis’. The very thought of having microbes in the body might elicit a negative, perhaps concerned reaction from someone not familiar with the importance of the gut microbiota; however, these tiny creatures play essential roles in their host’s nutrient metabolism. The bi-directional communication between the gut and the brain occurs due to a complex interplay between the central nervous system (CNS), autonomic nervous system (ANS), enteric nervous system (ENS) and the hypothalamus-pituitary axis.

Recent studies have shown connections between the presence of microbial population in the gut and anxiety, depressive disorders, and dysbiosis in autism. Mood disorders have also been linked to intestinal disorders. Studies on germ-free mice have established the importance of gut microbiota in the optimal development of the CNS and ENS. Mice without gut microbes displayed altered levels of certain proteins in the brain that aid in the growth and maintenance of nerve cells. Incorrect levels of these proteins (known as brain-derived neurotrophic factors) can cause a range of disorders related to the capacity to retain memory. Gut microbiota also produce neurotransmitters and neurohormones such as GABA and serotonin that can interact with the enteric nervous system. These are chemicals that jump from cell to cell passing the messages to and from the brain. These microorganisms contain landing pads for these chemicals (neurotransmitter receptors), therefore, they can respond to signals from the host’s brain. Studies have shown that introducing stressors like cortisol for a few hours is sufficient to change the microbial profile of the gut. The brain can activate receptors on these microbes and modulate the contraction and relaxation of the gut, which enables the food to pass through the digestive system in a timely manner. Furthermore, the gut-brain axis controls the secretion of stomach acid, mucous, and even unleashes an immune response if required.

Humans, for the longest time, have been consuming fermented food when experiencing discomfort due to digestive problems. Foods such as idli, kefir, miso, paneer, soybean, and kimchi are sources of good probiotic bacteria. Today, probiotics are consumed worldwide to maintain a healthy microbial profile, as the bacteria in these foods influence the microbial populations of the gut. Microbiome transplantation from one healthy individual to a diseased individual is an increasingly popular therapy to improve the microbiome profile. A good microbial profile is crucial for human health. Avoiding drugs, reducing sugar consumption, and incorporating fibres in the diet are some of the ways in which we can dramatically improve our gut microbiota. The role of the gut microbiome in maintaining human health is immense; researchers are continuously working on developing therapeutics aimed towards maintaining and improving the functions of these gut microbiota.

So, join in for some spicy kimchi with a gulp of kefir!

Author:

Shannon Rodriques has a bachelors in Life Science from the department of Life Science and Biochemistry, St. Xavier’s College Mumbai. His interest lies in biological science but his key areas of interest are in the fields of physiology, immunology and developmental biology. His favourite quote is by Issac Asimov who once said “The saddest aspect of life right now is that Science gathers knowledge faster than society gathers wisdom”. Shannon believes in bridging the gap between society and science by making science more simple and easy to understand through articles and other means of communication.

Editors:

Saurja Dasgupta is originally from Kolkata, India. He obtained his Ph.D. at the University of Chicago, where he studied the structure, function, and evolution of catalytic RNA. He is currently doing his postdoctoral research at Massachusetts General Hospital, Boston, where he is trying to understand the biochemical milieu that could have given birth to life on earth (and elsewhere) and reconstruct primitive cells. One of his scientific dreams is to observe the spontaneous emergence of Darwinian evolution in a chemical system.  When not thinking about science, Saurja pursues his love for the written word through poetry and song-writing (and meditating on Leonard Cohen’s music). His other passions are trying to make science easier to understand, and fighting unreason and pseudoscientific thinking with a mixture of calm compassion and swashbuckling spirit.

Sumbul Jawed Khan received her Ph. D. in Biological Sciences and Bioengineering from the Indian Institute of Technology Kanpur, where she studied the role of microenvironment in cancer progression and tumor formation. During her post-doctoral research at the University of Illinois at Urbana-Champaign, she investigated the gene regulatory networks that are important for tissue regeneration after damage or wounding. She is committed to science outreach activities and believes it is essential to inspire young people to apply scientific methods to tackle the challenges faced by humanity. As an editor, her aim is to simplify, translate, and excite people about the current advances in science.