ISLAMABAD - Fasting for regular periods could help protect the brain against degenerative illnesses, according to US scientists.

Researchers at the National Institute on Ageing in Baltimore said they had found evidence which shows that periods of stopping virtually all food intake for one or two days a week could protect the brain against some of the worst effects of Alzheimer’s, Parkinson’s and other ailments, The Guardian Health News Reported.

“Reducing your calorie intake could help your brain, but doing so by cutting your intake of food is not likely the best method of triggering this protection.

It is likely to be better to go on intermittent bouts of fasting, in which you eat hardly anything at all, and then have periods when you eat as much as you want,” said Professor Mark Mattson, head of the institute’s laboratory of neurosciences. Cutting daily food intake to around 500 calories which amounts to little more than a few vegetables and some tea for two days out of seven had clear beneficial effects in their studies, claimed Mattson, who is also professor of neuroscience at the Johns Hopkins University School of Medicine in Baltimore.

Scientists have known for some time that a low-calorie diet is a recipe for longer life. The link between reductions in energy intake and the boosting of cell growth in the brain might seem an unlikely one, but Mattson insisted that there were sound evolutionary reasons for believing it to be the case. “When resources became scarce, our ancestors would have had to scrounge for food,” said Mattson.

“Those whose brains responded best who remembered where promising sources could be found or recalled how to avoid predators would have been the ones who got the food. Thus a mechanism linking periods of starvation to neural growth would have evolved.” This model has been worked out using studies of fasting on humans and the resulting impact on their general health - even sufferers from asthma have shown benefits, said Mattson - and from experiments on the impact on the brains of animals affected by the rodent equivalent of Alzheimer’s and Parkinson’s. Now Mattson’s team is preparing to study the impact of fasting on the brain by using MRI scans and other techniques.

If this final link can be established, Mattson said that a person could optimise his or her brain function by subjecting themselves to bouts of “intermittent energy restriction”. In other words, they could cut their food intake to a bare minimum for two days a week, while indulging for the other five.

15 minutes of exercise a day may extend life by 3 years

Doing just 15 minutes of moderate exercise a day may add three years to your life, a large study in Taiwan has found.

Most people struggle to stick to the standard guideline of 30 minutes a day of exercise, five days a week, and experts hope that by identifying a lower dose, more people will be motivated to get off the couch.

Lead researcher Chi Pang Wen of Taiwan`s National Health Research Institutes said dedicating 15 minutes a day to a moderate form of exercise, like brisk walking, would benefit anyone.

“It’s for men, women, the young and old, smokers, healthy and unhealthy people. Doctors, when they see any type of patient, this is a one-size-fits-all type of advice,” Wen told Reuters in a telephone interview.

Wen and colleagues, who published their findings in medical journal The Lancet on Tuesday, tracked over 416,000 participants for 13 years, analysing their health records and reported levels of physical activity each year.

After taking into account differences in age, weight, sex and a range of health-related indicators, they found that just 15 minutes of moderate exercise a day increased life expectancy by three years compared to those who remained inactive.

“The first 15 minutes ... the benefits are enormous,” Wen said. Daily exercise was also linked to a lower incidence of cancer, and appeared to reduce cancer-related deaths in one person in ten.

“Sooner or later, you are going to die. But compared to the inactive group, the low exercise group has a reduction of 10 percent in cancer mortality,” Wen said.

Wen said the Taiwan findings were consistent with similar studies in the past using Caucasian participants, but his team was the first to come up with the minimum level of exercise necessary.

“None of the other papers were able to conclude ... what specific amount of exercise would be enough. Ours is the first one to say that 15 minutes would be enough,” he said.

“We hope this will make it more attractive for inactive people, that they can allocate 15 minutes a day, rather than 30, which is more difficult.”