Diet High in Animal Proteins Could Increase the Risk of Early Death: Study

A recent study shows that eating a diet that's rich in animal proteins during middle age could make you up to four times more likely to die of cancer than a low-protein diet--a mortality risk that's comparable to smoking, according to study authors.

"The research shows that a low-protein diet in middle age is useful for preventing cancer and overall mortality, through a process that involves regulating IGF-I and possibly insulin levels," study co-author Eileen Crimmins said in a release, via The Huffington Post. 

The study suggests that while eating proteins is often linked to a higher risk in cancer mortality, middle-aged individuals who also eat lots of proteins from animal sources-including milk and cheese, along with meat-are at an increased risk of early death, in general.

In fact, study findings showed that those who follow such a diet are 74 percent more likely to die of any cause within the study period than their more low-protein counterparts and also at an increased risk of diabetes.

Yet how much is too much?

''People talk about a balanced diet but no one knows what it is, particularly in terms of the balance of macronutrients, the ratio of protein to carbohydrate to fat,'' said David Le Couteur, a co-author of the study from the Charles Perkins Centre at the University of Sydney, via The Guardian. 

For the study, which was conducted on 900 mice, researchers put them on one of 25 diets, each with a different ration of proteins, fats and carbohydrates or with a reduced total energy content.

While the mice on the high-protein, low-carbohydrate diet showed signs of reduced body fat and consumed less food overall, they also had shorter lifespans and poor heart health.

Researchers said they believe this may have been due to the negative health effects of high-protein diets that can affect the branch of amino-acids in the body.

Yet on the other hand, mice that consumed a high-carbohydrate, low-protein diet were slightly rounder from an increase in body fat, with up to 10 percent more than the high-protein diet mice. They also lived longer and showed fewer signs of age-related health problems.

Lastly, those on the low-protein, high-fat diets were the least healthy and diet young, possibly due to restricted calorie intake and other issues.

More information regarding the study can be found via the journal Cell Metabolism.