High-protein diet as bad as smoking: Study

A high-protein diet could be as dangerous as smoking 20 cigarettes a day, according to a new study.

Researchers from the University of Southern California have found that people under 65 consuming high levels of dietary protein exposed themselves to a fourfold increase in their risk from cancer as against those on a low protein diet.

The increased mortality risk was equivalent to that of smoking 20 cigarettes a day.

According to the study of 6,318 adults over the age of 50, protein-lovers were 74 per cent more susceptible to early death from any cause than their low-protein counterparts. Their risk of death from diabetes was also several times higher than others.

The research defined a ''high-protein'' diet as deriving at least 20 per cent of daily calories from protein. According to the researchers middle-aged persons need consume around 0.8g of protein per kilogram of body weight, per day.

Even small decreases protein intake from moderate to low levels cut the likelihood of an early death by over a fifth. A "low-protein" diet includes less than 10 per cent of one's daily calorie intake from protein.

According to the author of the study Dr Valter Longo, professor of Biogerontology at the USC Davis School of Gerontology, animal-based proteins such as red meat, milk, and cheese were most harmful, but there was no evidence to suggest that protein from fish had a negative impact on the body, The Telgraph reported.

Healthline News quoted Longo as saying there was a misconception that because we all eat, understanding nutrition was simple. The question, he added, was not whether a certain diet allowed one to do well for three days, but could it help one survive to be 100?

The new study, which included 6,381 adults aged 50 and older who were followed for 18 years, was published yesterday in Cell Metabolism.

The study, however, found that the story was different for older adults. People aged over 65 who ate a high-protein diet had a 28 per cent lower risk of death from any cause as also a 60 per cent lowered risk of dying from cancer, as against those eating low amounts of protein.

However, consuming high amounts of protein still increased the risk of dying from diabetes.

According to the researchers, the apparent protective effect of high-protein diets in older adults, might have something to do with the growth hormone IGF-1. The level of this hormone decreased with age, which might contribute to the loss of muscle mass and increased susceptibility to disease and consume more protein, then, could help stimulate production of this hormone and maintain overall health as people aged.