Protein: How Much Is Too Much?
For those familiar with the Atkins diet, lower amounts of carbohydrate and greater amounts of protein intake beyond the RDA (Recommended Dietary Allowance) are essential components of Phase One, or “Induction”. Will this soften your bones or damage your kidneys?
Not really. There has always been some concern about bone health with increasing amounts of protein because of calcium loss, but this has been shown to be balanced by increased absorption from the intestine. As for damage to the kidneys, this stems from the need to restrict protein in patients who already have chronic kidney disease. There have been no studies showing that protein has any adverse effects in people with normal kidney function.
That said, the March issue of Applied Physiology, Nutrition and Metabolism contains an excellent review of a potentially controversial topic, “Protein requirements beyond the RDAs: Implications for optimizing health”.
The key term is “optimize”. It’s important to understand that the RDA, or Recommended Dietary Allowance, is not the optimal amount of protein you should be consuming; certainly not in the elderly. Instead, it’s the amount of protein below which you will start to lose nitrogen. Phrased another way, the RDA is the amount of protein you need to prevent your tissues from breaking down.
So from another perspective, what’s ideal in order to preserve long term health, not just survive? Presuming present good health and normal kidney function, shoot for 1.3 grams/kilogram of ideal body weight per day, which translates to about 90-100 grams of protein per day. And how do you figure that out? Here’s an easy way to keep track. It’s called the “Rule of 7”: There are 7 grams of protein in every egg and every ounce of meat, poultry or fish. Did someone say 6 grams? Don’t get hung up on statistics! It’s a handy working guide.
Here are a few additional key points:
- To preserve muscle mass, older adults need higher protein intakes e.g. > 1.2 g/kg day.
- Include a high-quality protein source at breakfast, e.g. 25+ grams. (Good protein sources are animal based rather than plant based)
- Higher protein diets help control hunger and increase the burning of calories, or thermogenesis. It’s one of the key reasons why low carbohydrate diets work.
Journal Abstract
Phillips, S. M., S. Chevalier, et al. (2016). “Protein “requirements” beyond the RDA: implications for optimizing health.” Appl Physiol Nutr Metab: 1-8.
Substantial evidence supports the increased consumption of high-quality protein to achieve optimal health outcomes. A growing body of research indicates that protein intakes well above the current Recommended Dietary Allowance help to promote healthy aging, appetite regulation, weight management, and goals aligned with athletic performance. Higher protein intakes may help prevent age-related sarcopenia, the loss of muscle mass, and strength that predisposes older adults to frailty, disability, and loss of autonomy. Higher protein diets also improve satiety and lead to greater reductions in body weight and fat mass compared with standard protein diets, and may therefore serve as a successful strategy to help prevent and/or treat obesity. Athletes can also benefit from higher protein intakes to maximize athletic performance given the critical role protein plays in stimulating muscle protein remodelling after exercise. Protein quality, per meal dose, and timing of ingestion are also important considerations. Despite persistent beliefs to the contrary, we can find no evidence-based link between higher protein diets and renal disease or adverse bone health. This brief synopsis highlights recent learnings based on presentations at the 2015 Canadian Nutrition Society conference, Advances in Protein Nutrition across the Lifespan. Current evidence indicates intakes in the range of at least 1.2 to 1.6 g/(kg.day) of high-quality protein is a more ideal target for achieving optimal health outcomes in adults.