You can never have too much of a good thing, right? Unfortunately, in regards to protein, specifically animal protein, there is increasing evidence to show that too much animal protein can be harmful. This is a follow up to my last article regarding protein supplementation. Protein supplementation is often sourced from whey protein, found in dairy products. Recent fad diets, such as the Atkins or other similar low carbohydrate diets, also have placed a heavy emphasis on animal protein.
Data from the National Health and Nutrition Examination Survey indicate that Americans get as much as 46% of their protein from animal products and 16% of their protein from dairy products. Plant protein made up about 30% of intake. ( 8% of protein was not classified). Chicken and beef were the primary sources of animal protein; while cheese, milk , and dairy desserts were the main sources of dairy protein intake. Plant protein sources included mostly bread, nuts, and seeds.(1)
One adverse effect of high animal protein intake is an increased risk of kidney stones. The connection between high protein intake and kidney stone onset or recurrence has been demonstrated in a large epidemiologic study carried out in male healthy male subjects, published in the New England Journal of Medicine . (2) A reduction in animal protein intake is very effective in preventing kidney stone relapse combined with a reduction in salt intake and an increase in fruit and vegetable intake, whereas a high protein low carbohydrate diet can contribute to the formation of kidney stones.(3)
In addition, high protein intake is associated with renal insufficiency since the kidney filters the protein in the body. In those with renal insufficiency, lower protein intake may slow the progression of advanced renal disease.(4) There is also an increased risk of diabetes type 2 with a diet higher in animal protein and a modestly reduced risk with a higher intake of vegetable protein.(5)
Therefore, if you are concerned about getting enough protein for building muscle, I recommend getting vegetable protein instead of animal protein. In the International Study of Macro-/micronutrients and Blood Pressure (INTERMAP), patients who have lower risk for cardiovascular disease had a higher intake of vegetable protein and lower intake of animal protein.(6) A diet with a higher proportion of protein from plant sources is associated with lower mortality in those with chronic kidney disease as well.(7) As I mentioned from my last article though, it is unlikely you really need the extra protein supplement at all.
(7) Chen, X et al. “The Associations of Plant Protein Intake With All-Cause Mortality in CKD.” Am J Kidney Dis. 2016 Mar;67(3):423-30. Web. 24 July 2016.