High-protein diets like the Paleo Diet and the Atkins Diet have long been associated with bodies packed with muscle and low in fat. They also have been suggested by many as a way to lose weight quickly. But a new study suggests that high protein diets may increase cancer risk, especially if a person is between the ages of 50 and 65.

The study titled Low Protein Intake Is Associated with a Major Reduction in IGF-1, Cancer, and Overall Mortality in the 65 and Younger but Not Older Population was published in the journal Cell Metabolism on March 4, 2014, and already media outlets are pouring over the results.

In the study, researchers followed 6,381 adults aged 50 or over that represented a cross-section of society, meaning the study population is representative of the United States population in terms of ethnicity, education, and health characteristics. Participants in the study reported dietary intake and were divided into three categories regarding protein intake.

The first group was called the “high protein group” and consisted of individuals whose protein intake was at least twenty percent of their total calorie intake. The second group was called the “moderate protein group” and consisted of individuals whose protein intake was between 10 and 19 percent of their total calorie intake. The final group, the “low protein group” was anything beneath that.

Results showed that both high and moderate protein groups were at a higher risk for diabetes mortality compared to the low protein group. Researchers noted however that this needed further study to solidify the link.

Results also showed that among those between the ages of 50 and 65, high protein levels were linked to significantly increased risks of all-cause and cancer mortality. In this age group, those in the high protein group were four times more likely to die of cancer than their low protein group counterparts.

When researchers analyzed the animal-plant protein variable, they found that when they removed animal protein from the statistical sample, the link between high protein consumption and mortality disappeared. Researchers suggest that consuming a high level of animal proteins can lead to death by all health-related causes, including cancer.

Participants aged 65 or older actually need more protein than those in the low protein group, due to the fact that those over 65 suffer from protein malnourishment as their body weight starts to drop.

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