How much protein you need is the stuff of myths and controversies. Who is right? Who do you believe?

A professor from Eastern Michigan University and a Nutritional Physiologist for the United States Army Research Institute of Environmental Medicine recently teamed up to discuss the science around dietary protein and address a few misconceptions.

Here are a few common protein myths:

• The RDA is the optimal protein intake amount
• Lower protein helps keep your bones strong
• Lower protein keeps your kidneys healthy
• Lower protein leads to less inflammation

The authors clearly addressed why each of these is incorrect, countering unfounded myths with science. The truth is:

1. The RDA for protein is the minimum amount required, not optimal

The RDA (Recommended Dietary Allowance) for protein is 0.36g/lb/day (or 54 grams for a 150-pound person). This amount is often misunderstood as the optimal intake, when in reality it is only the minimum amount needed to prevent muscle mass loss in 97.5% of the U.S. adult population.

A healthy, optimal amount is generally higher, especially for athletes, those building muscle, dieters and older adults. Over the past two decades, science has clearly shown the potential muscle-related benefits achieved by consuming more than the RDA of protein.

2. Increased protein intake may actually protect bone mineral density

Nearly a century ago, higher calcium levels were found in the blood of those consuming higher amounts of protein. It was later hypothesized the calcium was being pulled from the bones into the blood causing bones to weaken—and so the myth started. However, that’s not what really happens.

Recent data from well-controlled studies has shown that the observed higher levels of calcium in the blood due to higher protein intake actually results from increased calcium bioavailability and greater intestinal absorption.

In fact, higher protein diets may actually protect against osteoporosis. A recent meta-analysis demonstrated that those with the highest protein intakes had significantly lower hip fracture incidence relative to those with the lowest protein intakes. Increased protein intake may actually be protective of bone and serve a critical role in accruing and maintaining bone mineral density.

3. Higher-protein diets are safe for the kidneys of healthy adults

Some people say too much protein is bad for your kidneys. This is true if you already have kidney disease. In a recent evaluation of NHANES data, those in the top 10% for protein intake (~0.64g/lb/day) of non-dairy animal, animal and plant protein sources still exhibited normal kidney function.

That’s about 96 grams of protein for a 150-pound person, well above the 54 gram minimum RDA.

Overall, the researchers concluded the currently available data suggests that higher-protein diets do increase renal workload, but they do not negatively impact kidney health nor increase the risk of developing chronic kidney disease in healthy adults.

4. More protein is associated with less inflammation

A few people assume that higher-protein intakes might increase systemic inflammation. However, an analysis of the Framingham Heart Study Offspring Cohort shows just the opposite. Higher protein intake was associated with lower inflammation and oxidative stress scores when measuring nine inflammatory biomarkers.

This potential beneficial effect was observed for higher total protein intake and higher animal protein intake but was even more pronounced with higher plant protein intake.

In summary, protein has become a hot research topic over the past two decades, but there has been a lack of change in the American diet in response to this research. This may be a result of common misconceptions and myths about protein intake.

The authors strongly encourage the reevaluation of protein recommendations based on high-quality science.

Reference: Nutrients; 2019, 11(5), 1136.

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