Protein Requirements

It’s time for lunch or dinner again and you may be trying to decide if it should be chicken, fish or maybe even beef. After all, we know protein is important and it will help us lose weight and build muscle. So what about all those vegetarians or maybe even vegans out there? Do they eat beans all day to get enough protein?

It is true that protein is used for building and repairing muscle and tissues, red blood cells, hair and finger nails. Protein is a necessary macronutrient and we would die without it. However, most of us are more likely to be at risk of excess protein consumption than protein deficiency. The body stores very little protein. Any excess protein consumed is converted to fat (not muscle mass). Excess animal protein intake has been linked to liver and kidney problems, arthritis, osteoporosis and digestive issues. In the China study conducted by T. Colin Campbell, PhD., groups of people who ate the most animal protein had the most heart disease and certain cancers. Dan Buettner investigated dietary habits of centenarians in some of the world’s populations with the highest concentration of centenarians and recommends in his book “Blue Zones” to limit meat to twice a week.

The world health organization established a daily protein requirement that is less than the US R ecommended Dietary Allowance (RDA).

• WHO Daily Protein Requirement: 0.45 grams of protein per kilogram (2.2 pounds) of ideal body weight per day. *

• US RDA Daily Protein Requirement: 0.8 grams of protein per kilogram (2.2 pounds) of ideal body weight per day. *

The table below gives the daily protein requirement by ideal weight. The lower value is based on the WHO recommendation and the upper value is based on the US RDA.

*Protein requirements are different for children, adolescents and during pregnancy or lactation

The table below provides Recommended Dietary Allowance for Protein   by age as provided by the Center for Disease Control (CDC)

Protein in some common Vegan Foods

Protein in Meat and Animal Products

Looking at the tables above, it seems to be more of a challenge to stay below the US RDA for protein not to mention the significantly lower WHO recommendations. Many people already consume 1.5 to 2 times the recommended RDA.

Protein Requirements for Athletes

There is some debate on whether the RDA is sufficient for athletes. The American Dietetic Association recommends a protein intake to 1.6 to 1.8 gآper kg body weight per day for strength-trained individuals (American Dietetic Association et al., 2000). Some experts question this recommendation citing shortcomings of the laboratory procedure used to justify the increased protein RDA (field-based nitrogen balance).

Dr. Longo and colleagues question the heightened RDA requirements in their Letter to the Editor of the Journal of Sports Science and Medicine (Dec 2008) entitled "The best athletes in ancient Rome were vegetarian!" The authors point out that analysis of some remains of ancient gladiators of Rome point to the fact that they may have been vegetarian. It is also mentioned that “ Observational studies of vegetarian and non-vegetarian athletes (Hanne et al., 1986) have found no differences in performance or fitness associated with the amount of animal protein consumed.”

Sources:

Longo, et. al, "THE BEST ATHLETES IN ANCIENT ROME WERE VEGETARIAN!", Journal of Sports Science and Medicine (2008) 7, 565

USDA Nutrient Database for Standard Reference, Release 18, 2005 and manufacturers' information.

Author: Angela Hubner

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