Fast lane to health

Study shows calorie restriction can help achieve longevity and good health

 
By Manupriya
Last Updated: Saturday 04 July 2015

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EVER wondered how your grandmother regularly kept fasts even in old age and still managed to have a long and healthy life? Turns out, fasting itself is the secret. Scientists have found that apart from virtues like healthy eating and exercising, calorie restriction can help achieve longevity and good health, the two major goals of biological research today.

A team of scientists, led by Liping Zhao of State Key Laboratory of Microbial Metabolism at the School of Life Sciences and Biotechnology of Shanghai Jiao Tong University, in China, have found that calorie restriction can enhance the population of gut microbes that have a positive co-relation with life span.

For their experiment, they divided mice in two groups: one was kept on a low fat diet and other on a high fat one. Each group was then subdivided into three smaller groups—one performed sedentary activity, second performed sedentary activity and was kept under 30 per cent calorie restriction and the last exercised but had no calorie restriction. When scientists analysed the type of microbes present in each of the six groups, some interesting facts came up. They noticed that with every change in diet and lifestyle the composition of microbial population in the gut of the mice also changed.

imageIn their study, published in Nature Communications on July 16, the scientists wrote that irrespective of whether the diet was high-fat or low fat, calorie restriction increased the population of bacterial species linked with longer life span and decreased those that were negatively correlated with lifespan. The group subjected to both low fat diet and calorie restriction turned out to be the healthiest at the end of the experiment. The gut population of this group had astonishingly high population of bacteria of Lactobacillus species and lowest levels of Streptococccae and TM7. Studies have shown that Lactobacilli increase gut’s ability to fight infection whereas Streptococcae and TM7 perform no such roles and can be linked to inflammation. Yoghurt or curd, which is routinely consumed in Indian households, is loaded with Lactobacilli.

Fasting, which is a common religious practice in India, is a definite form of calorie restriction. Does this mean that over the years, the Indian population has gained something in terms of good health and life span through fasts? Unfortunately, no scientific study has explored the connection between fasting and its impact on human health as yet. So the answer remains shrouded in mystery. It is, however, important to understand that sometimes fasting is confused with binging on a potato-rich, high-fat diet. That does not amount to calorie restriction.

Many other aspects of calorie restriction have also been studied. A 2011 study, published in Biochemical and Biophysical Research Communications by a team of researchers from Central Drug Research Institute in Lucknow, evaluated the effect of calorie restriction on neurodegenerative disorders like Parkinson’s disease. Working with Caenorhabditis elegans—the favourite worm of scientists for aging-related studies—they found that calorie restriction enhances production of sirtuin protein. “This protein mediates the protection of dopamine synthesizing neurons, thereby increasing the levels of neurotransmitter dopamine. We believe that calorie restriction can have major implications in prevention and cure of age-associated diseases like Parkinson’s,” says lead author Aamir Nazir.

He also says the same protein is produced in excess while exercising. This makes one wonder if calorie restriction can be a replacement for exercise. Aamir says the benefits of exercise span far beyond just burning calories. “Hence a healthy exercise regime cannot be replaced,” he says. Aamir further cautions that the meaning of calorie restriction may vary from individual to individual and will depend on the body weight, fat storage and activity level.

But Rekha Sharma, the president of Delhi-based India Dietetic Association, is not convinced. “Calorie restriction causes more harm than benefit as it lowers the basal metabolic rate of the body,” says Sharma. She certainly does not recommend fasting over regular exercising. While scientists may agree or disagree over the benefits of calorie restriction, more studies, and those too on human subjects, are needed to reach a conclusion.

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