Raising questions, busting myths around the pedestrian but venerated curd

For the vast majority of residents of the Indian subcontinent, curd in some form or other is an essential item of the daily menu. Particularly in the punishing summer, solicitous grandmothers insist to this day that children consume it religiously, considering it a panacea for every ill ranging from a parched palate to an upset stomach. This well-integrated member of most regional Indian cuisines has also traditionally served as a countervailing force to the infamous Indian spice intake. Data by the Indian Council of Agricultural Research (2012) suggests that seven per cent of the country’s total annual milk production — and India is the world’s largest producer of milk — is used to make curd for direct consumption.

But few of us have thought to consider exactly why curd is so popular. Perhaps one can start by blaming Ayurveda. This system of medicine prescribes curd as a home remedy for conditions ranging from dysentery, loss of appetite, urinary problems and general debility. According to Alakananda Ma, an Ayurvedic doctor who is a member of the National Ayurvedic Medical Association, curd has both sour and sweet properties, which means in turn that different kinds of curd have different effects on the body. “Sweet curd increases mucus, kapha (governs weight, growth, lubrication of joints) and fat; acidic curd deranges pitta (controls digestion and metabolism) and kapha; and extremely acidic dahi vitiates the blood,” says Ma. “So, while it is a product that has many benefits, it is only beneficial if it is eaten with care,” she asserts.

Curd contains lactic acid bacteria called lactobacillus, which are “probiotic” or healthy bacteria that are introduced into the body to promote the growth of healthy gut bacteria. Allopathic doctors too routinely prescribe doses of lactobacilli when treating infections with antibiotics.

Less known, though, is the fact that the probiotic content of the widely available homemade curd varies considerably from home to home. This lack of standardisation in terms of the types of strains of good bacteria present in homemade curd and its count per a specific amount of curd calls its probiotic properties into question.

Meanwhile, in the era of convenience foods made for the harried urbanite short on time, packaged probiotic curd, Greek yoghurt and little bottles of the probiotic drink, Yakult, leave the shelves faster than the time it takes to say FMCG. Products like kefir milk (a fermented milk drink similar to thin yogurt made with kefir grains) and kombucha (a fermented, slightly alcoholic, sweetened black or green drink), both items of Eastern European provenance, have found a safe little corner in the urban Indian’s shopping basket.

Yoghurt (think packaged yoghurt like those sold under the Epigamia brand) contains two specific strains of bacteria called Lactobacillus bulgaricus and Streptococcus thermophilus. Other strains of lactic acid bacteria may be present too, depending on the brand of yoghurt. Experts say that the addition of specific strains, and an understanding of what these strains are beneficial for, help make these commercially produced products a more reliable form of probiotic consumption than homemade curd.

Research on probiotics is said to have begun in 1907 as Russian scientist and Nobel laureate Élie Metchnikoff suggested that gut flora could be modified and improved by replacing harmful microbes with useful, healthy microbes. Nearly a century later, probiotics have become trendy essentials with people shifting to healthier lifestyles. Along with organic food, probiotics came to be looked at as “functional foods” — foods that provide health-enhancing properties beyond their nutrients. The probiotic content of cultured foods like yoghurt, fermented vegetables like the Korean kimchi and the German sauerkraut, and even nutrition bars, are tom-tommed routinely. Probiotic supplements with greater clarity about the number and type of healthy bacteria they contained became common in markets, especially in the West.

Now, extensive research on indigenous strains of bacteria is helping address the problem of standardisation in the creation of probiotic products such as packaged curd. J B Prajapati, head of the dairy microbiology department at Anand Agricultural University in Gujarat, has been working on Lactobacillus helveticus and Lactobacillus rhamnosus for more than 25 years. The former bacterial strain is known for its ability to remove allergens and other undesired molecules from food; the latter may help prevent urinary tract infections and provide health benefits such as better digestion. “We have standardised several types of dahi (curd), lassi (sweet buttermilk) and buttermilk which contain these beneficial bacteria,” says Prajapati.

Scientists Virender K Batish and Sunita Grover, at the National Dairy Research Institute (NDRI) in Karnal, have been working on Indian strains of probiotic bacteria. Their laboratory has a repository of 120 strains. The scientists plan to market two types of bacteria soon — Lactobacillus plantarum-91 (Lp-91) and Lactobacillus fermentum-1 (Lf-1). “The two strains are quite promising. Lp-91 has been shown to lower cholesterol in animals by 21 per cent. We are ready to conduct studies on humans now,” Grover says. The scientists plan to screen all bacterial samples to see which of them can induce a feeling of satiety after meals — a feature that can help deal with India’s looming obesity problem.

Milk products producer Mother Dairy was one of the first companies to introduce indigenous probiotic curd to the Indian market. Theirs was the first “synbiotic” fermented product (a combination of probiotics and prebiotics, the latter being a type of dietary fibre that “feed” the probiotic bacteria). It contains strains of Bifidobacterium animalis (BB 12) and Lactobacillus acidophilus (A-5), both of which are established “healthy bacteria”. Mother Dairy describes their regular curd as resembling the homemade variety without any of the effort required to make it. They make no mention of its probiotic content.

Manish Gupta, consultant, gastroenterology and hepatology, at Paras Hospital in Gurugram, says that both curd and yoghurt have comparable probiotic content, though the strains of good bacteria in homemade curd remain difficult to identify. Shikha Sharma, a nutritionist and founder of Nutri Health Systems, also explains that commercially prepared curd that carry the “probiotic” label contain added healthy bacterial strains, which make it a richer source of probiotics than both homemade and store-bought curd.

Thus, while probiotic curd contains a higher count of healthy bacteria, curd in general, whether homemade or packaged, is not to be discounted on the probiotic front. That said, its benefits may be exaggerated as the strains present may not be strong enough to fight the acidic environment of the stomach and multiply effectively to promote health and immunity. The moral of the somewhat complicated story: Don’t treat everything your grandmother told you as gospel.