Bacteria and yeasts have been making food tastier for centuries: the curds so common in most Indian cuisines, the cheeses of Western cuisine, our fermented idli-dosa-dhokla batters, relishes of fermented fish, and an assortment of
alcoholic beverages. And yet it’s taken us a while to ascertain that they have more than taste benefits; they can have health benefits too.
About a century ago, Nobel laureate Ilya Ilyich Mechnikov, who was recognized for his work on phagocytosis, said, “Lactic acid bacteria can render a great service in the fight against intestinal putrefaction… (and can) postpone and ameliorate old age”.
In the 21st century, enter the cult of functional foods. Joining the race with older panaceas such as “low-fat”, “wholegrain” and antioxidant-rich “superfood” are “probiotics”, with their promise of a healthier life—probiotic is Greek for “for life” (to read more about probiotics, visit www.livemint.com/probiotic.htm).
In the ongoing debate about the actual benefits of probiotics, and all the hoopla over introducing specific strains of goodness into the gut (not every Bifidobacteria, Lactobacilli or other bacteria are worthy of a probiotic title, only those proven to have a positive effect), we sometimes overlook the fact that these bacteria already have a home...inside us.
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Bacteria in your belly, already
Probiotic foods may replenish or bolster stocks of beneficial bacteria in those who find their original levels of bacteria in the gut depleted by illness or antibiotics.
But probiotics aren’t introducing anything your body didn’t have in the first place. What must come entirely from outside, in fact, is not the bacteria but the stuff they feed on: prebiotics.
After all, the reason these symbionts live in our digestive tracts is to partake of the food we eat. The foods these bacteria prefer are indigestible by humans: They are “nondigestible food ingredients that beneficially affect the host by selectively stimulating the growth of one or a limited number of bacterial species in the colon, such as Bifidobacteria and Lactobacilli which have the potential to improve host health” (Ashwell M., Concepts of Functional Foods, 2002). That is, in fact, the textbook definition of “prebiotics” (meaning “before life”).
Prebiotics, nourishment by proxy
A true prebiotic must abide by three rules.
Rule 1: It must not be broken down in the stomach, nor be absorbed in the gastrointestinal tract. That is, it must get to the bacteria, not get eaten by the human host.
Rule 2: It must then be fermented by these bacteria.
Rule 3: It must preferentially nourish those bacterial strains that are known to benefit the host’s health.
So prebiotics seem designed to nourish the bacteria that nourish your health. Indeed, some prebiotics go one step further. Studies from the last decade suggest that some prebiotics help us absorb minerals such as calcium and magnesium better; others may protect us against colorectal diseases, or even ameliorate our lipid levels (cholesterol and triglycerides).
Building blocks of bacterial benefit
These are foods so old that some of us are in danger of disregarding them. Prebiotics are found in common foods: whole grains such as (unprocessed) oats, wheat and barley, legumes, fruits such as bananas, vegetables such as onions, garlic, tomatoes and leafy greens, and even the humble jicama (sankalu). Researchers know them as inulins, oligosaccharides, galactans, polydextrose and polyols. For many scientists, all this recent research is directed towards the Holy Grail of immunity-in-a-pill, a mix of probiotics and prebiotics, called “synbiotics”. But for layfolk, it may be a rediscovery of old-fashioned wholesomeness.
The author is a deputy features editor at Mint.
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