Could High-Protein Diets in Mid-life Reduce Lifespan?

Key Takeaways:

• Excessive consumption of animal proteins, such as meat and dairy, during mid-life may potentially reduce lifespan.
• People in their 50s who consume more than 20% of their calories from animal proteins could quadruple their risk of death due to cancer or diabetes and double their risk of death from any cause over the next 18 years, compared to those who follow low-protein diets.
• However, people older than 65 who consume large quantities of animal proteins had a 60 percent lower risk of fatality from cancer and a 28 percent lower risk of death from any cause compared to those who limit meat and dairy intake in their diet.
• The co-relation between protein consumption and the risk of early death could be due to the activation of natural growth hormone and a cellular growth factor called IGF-1.
• A parallel study in mice also found high-protein, low-carb diets to shorten their lifespan.

There are numerous individuals who, during their middle years, frequently enjoy protein-rich foods such as steaks and cheeseburgers. However, recent studies suggest that excessive consumption of meat and cheese during mid-life could potentially reduce one’s lifespan.

Understanding the Connection between Protein-Rich Diets and Lifespan

These studies, surprisingly, found that consuming a lot of protein from animals may have the reverse effect as we age.

“Our findings indicate that a low-protein diet in middle age could prevent cancer and mortality in general,” said study co-author Eileen Crimmins, AARP Chair in Gerontology at the University of Southern California. She also proposed that “avoiding a low-protein diet may be significant in old age to maintain a healthy body and protect against frailty.”

Pivotal Findings Published

The conclusions of these studies were published on 4th of March in the esteemed journal, Cell Metabolism.

Insights from the Study

In the study which examined data from over 6,800 middle-aged and elder citizens of the United States, 50-year-olds who consumed more than 20% of their calories from animal proteins such as meat or dairy increased their risk of death due to cancer or diabetes fourfold. Their risk of death from any cause approximately doubled in the following 18 years, compared to those who followed low-protein diets.

Interestingly, middle-aged individuals who consumed “moderate” levels of animal proteins still found that their risk of fatality due to cancer tripled.

Conversely, those who followed a plant-based high-protein diet in their 50s experienced a significantly lower risk, or none at all.

Furthermore, the study demonstrated that individuals older than 65 who consumed large quantities of animal proteins had a 60 percent lower risk of fatality from cancer and a 28 percent lower risk of death from any cause compared to those who limited meat and dairy intake in their diet.

Reducing Protein Intake

“Many Americans consume roughly double the protein they require, with the best course of action being reducing daily protein intake, especially animal-derived proteins,” Dr. Valter Longo of the University of Southern California and the senior author of the study, said. He warned, however, not to drastically cut protein intake as it could quickly lead from protection to malnutrition.

Parallel Study on Mice

A parallel study conducted on mice found that a diet high in protein and low in carbohydrate shortened their lifespan.

The study’s senior author, Dr. Longo, believes that a diet high in protein, particularly if the proteins are animal-derived, is nearly as detrimental to health as smoking.

Linking Protein to Early Death

The co-relation between protein consumption and the risk of early death may partially result from the activation of natural growth hormone and a cellular growth factor called IGF-1. “It’s important to note that the activity of these factors, along with body weight, naturally declines with aging. This may explain why older people did not benefit and seemed to fare worse on a low-protein diet,” added Dr. Longo.

Implications of the Study

The research findings stand to further our understanding of diet and health connections. “We’ve explicitly demonstrated that not all calories are equal. We need to understand where the calories are derived from and how they interact,” Steve Simpson, senior author of the mice study, commented.

“This research has significant implications for our daily food intake, body fat, heart and metabolic health, and ultimately our lifespan,” added Simpson, a researcher at the University of Sydney.

Additional Information

The U.S. National Library of Medicine has further details on dietary proteins.