Fasting and feasting are a very common process seen in most of the religions and communities across the world. A recent study from the University of Florida suggests that intermittent fasting is actually good and could help in the longevity of life.
In this study 24 participants were fasted (partial fast) and fed well on alternate days for a period of three weeks. On fasting days the participants were fed only a single meal with roast beef and gravy, mashed potatoes, Oreo cookies and orange sherbet that would contribute to only 25 percent of an average daily calorific value for an individual. On the other hand, the feasting day’s menu included bagels with cream cheese, oatmeal sweetened with honey and raisins, turkey sandwiches, apple sauce, spaghetti with chicken, yogurt and soda — and lemon pound cake, Snickers bars and vanilla ice cream that comes to 175 percent of an average daily calorific value.
The participants were tested for changes in weight, blood pressure, heart rate, glucose levels, cholesterol, markers of inflammation and genes involved in protective cell responses over 10 weeks. Also the researchers noticed that sirtuin proteins such as SIRT3 and another, SIRT1, tended to increase as a result of the diet. Interestingly SIRT3 gene expression is known to increase in mice as a result of fasting resulting in extended lifespan and to improve age-related diseases.
Researchers believe that SIRT3 protein levels go up due to the oxidative stress triggered by the free radicals generated during fasting. Small levels of these free radicals can be beneficial: When the body undergoes stress — which happens during fasting — small levels of oxidative stress can trigger protective pathways, Guo said. However prolonged and very frequent fasts would result in excess free radicals generation that damages the cells of the body.
Interestingly the increase in the levels of SIRT proteins was not noticed in participants who were on antioxidant supplements in addition to the ‘fast and feast cycles’. This suggests that the free radicals in these individuals were taken care or suppressed by the antioxidants hence no elevation in SIRT proteins observed. “This is in line with some research that indicates flooding the system with supplemental antioxidants may counteract the effects of fasting or exercise,” said Christiaan Leeuwenburgh, Ph.D., co-author of the paper and chief of the division of biology of aging in the department of aging and geriatric research.
“People don’t want to just under-eat for their whole lives,” said Martin Wegman, an M.D.-Ph.D. student at the UF College of Medicine and co-author of the paper recently published in the journal Rejuvenation Research. “We started thinking about the concept of intermittent fasting and found that intermittent fasting caused a slight increase to SIRT3, a well-known gene that promotes longevity and is involved in protective cell responses,” said Michael Guo, a UF M.D.-Ph.D. student who is pursuing the Ph.D. portion of the program in genetics at Harvard Medical School. This study should further focus on the global gene expression profile changes during fasting with focus on the muscle and fat tissue in a larger cohort of individuals.
So, fasting once in a while is not bad, after all!
The original publication can be accessed here.