How much Protein Serving?

There has been much debate on how much protein we can safely digest in one serving or meal, supplement companies all recommend different serving sizes for their products and most references seem to refer to a study done in the 1970′s on subjects with pre-existing health problems and how a high protein diet put additional strain on their kidneys and renal system. The UK Food Standads Agency state as a guideline on their website; “The daily recommendation for adults (over the age of 19) is 55 g protein per day. But it’s the balance of foods we eat over a few days that’s important, rather than what we eat every day. So if you don’t manage to eat much protein on one day, you should aim to eat a bit more over the next few days.
This is because the body contains a small reserve of protein so it can cope with day-to-day variations. However, eating large amounts of protein is bad for the kidneys, so it’s important not to eat too much protein, and it’s especially important to keep within twice the recommended amount.” They do not support any of the above with any evidence.

The American Heart Association (AHA) stated in 2001 “Individuals who follow these (high protein) diets are risk for potential cardiac, renal, bone and liver abnormalities overall.” This sweeping statement must cause concern and in turn deter many people from following an Atkins type high protein diet plan which incorporates a reduction in carbohydrate intake.

The justification of such a statement is unclear as there is no scientific evidence that high protein intake has adverse effects on liver function. Relative to renel function there is no scientific ducumentation to support the theory that healthy kidneys are damaged by the increased demands of protein consumed at 2 – 3 times the Recommended Daily Allowance (RDA). A study by Portman Dellalieux investigated bodybuilders and other highly trained athletes with medium to high protein intakes. The athletes underwent a 7 day nutrition record analisys as well as blood sample and urine collection to determine the potential consequences of such a diet. The subsequent data showed despite higher uric acid and calcium the athletes had renal clearances of creatinine, urea and albumin which were al considered to be within a normal range. This admittedly short study was done with protein ingestation of up to 2.8gr/kg of bodyweight, 3.5 times as much as the recommended daily allowance.
In contrast to the theory that a high protein diet promotes osteoporosis, there has been some epidemiological studies showing a positive effect of protein intake and bone mineral density, further to that recent studies suggest over a short period the RDA of 0.8gr/kg of protein does not support calcium homeostasis.

Finally a negative relationship has been found between protein intake and blood pressure in several epidemiological surveys(Honolulu Heart Study 6406 cases studied, Chinese Study 2672 cases and MRFIT Study with 11342 adult males studied), all these factors show there is little if any hard and fast scientific evidence to support the above AHA statement. For healthy individuals with normal renal function the risks of a high protein diet are minimal.

Dr. Eric L. Knight, a researcher at Brigham and Women’s Hospital and Massachusetts General Hospital in Boston concluded after studying the effects of protein consumption vs kidney function that, “Based on this study, I would say in individuals with normal kidney function, we have no reason to believe that a relatively high protein intake has a harmful effect on the kidneys.” The findings appear in the March 2003 issue of the Annals of Internal Medicine.

So what does this really mean to people concerned with increasing muscularity, wanting to maintain a protein based diet to control fat levels or those involved in an intense exercise program which stresses skeletal muscle? I think it shows that anecdotal evidence relating to high protein intakes doesn’t relate to the people who are most likely to be consuming the most protein, almost all studies are done on people with medical problems which a high protein intake may effect negatively, the studies I have mentioned which were done on healthy individuals who exercised to a degree found no problems.

This I believe shows the old 30gr of protein per seving theory to be not only out dated but also incorrect, this figure was a conclusion drawn by an American study done in the 1970′s on recovering alcohilics who were suffering from a degree of liver and renal failure. It was found that servings of over 30gr protein at any one time was not fully digested and caused stress to the subjects renal system as the demands put on the kidneys to process the additional nitrogen and elevated urea production were increased.

Could someone like Ronnie Coleman build such a physique on 6 meals a day containing 30gr of protein? I think not, my own theory which is only my theory, is that as a naturally skinny person who can eat large amounts of fat, carbohydrate and protein without getting fatter or more muscular has a body whch process nutrients without storing them. Where the narurally fat person is the exact opposite, whatever they eat tends to be stored well, good or bad.

I believe as individuals with differing numbers of muscle fibers and muscle density we can all digest differing amounts of protein, the demands we all put on our bodies mentally and physically differ greatly so does our ability to deal with them this alone will have an effect on our ability to digest protein. Until a study is done on people who are pushing the boundaries of protein consumption I think we must do what we feel to be right for ourselves and follow what seems to allow us to recover from our chosen form of exercise swiftly and allow those of us who want added muscle tissue to still have enough excess protein in our diet to support this new tissue growth.