is high protein diet safe?

There is an increasing concern over the ill-effect of taking protein supplements among generally health conscious people, who swears off carbs but welcomes a larger portion of protein into their diet. Anecdotal experiences have reported kidney failures and kidney stones affecting those who consumes a huge amount of protein. This causes some anxiety as whether one should start taking protein supplements at all.

As a rule of thumb before we continue, balanced and fresh whole food is always preferred to popping supplement pills and nutrition shakes. Now that I've made clear my obligatory health message, we can discuss high protein diet with better conscience.

People consume high protein intake mainly for 2 reasons. Firstly as a body building supplements for the bodybuilders, and secondly, though with varying results, as a weight loss regime. High protein diet is defined as a daily consumption of greater than or equal to 1.5 g/kg/day. That means, for a person weighing 75kg, he would have to eat slightly more than half a kilo of chicken breast a day.

A study was done to review the existing evidence regarding the effects of protein intake on kidney function with particular emphasis on kidney disease. The findings have shown that while high protein intake may worsen the kidney function of those with pre-existing kidney problem, it did not affect those with normal and healthy kidneys, even when one has risk of kidney disease such as high cholesterol level, high blood pressure and obese.

With regards to kidney stone, the study also found that it is not likely that diet alone causes stone formation, rather, metabolic abnormalities is the bigger culprit.

The study concluded that at present, there is no sufficient proof that high protein diet causes deterioration of kidney function in an otherwise healthy individual.

However, since a compromised kidney function may not be symptomatic in the early stage, it is always recommended that you have your kidney health checked and consult your doctor before getting that tub of whey.

The normal kidney test parameters are as follows:

1. Urea (3.0-8.0 mmol/L)
2. Creatinine Female (0.04 - 0.11 mmol/L)
3. Creatinine Male (0.04 - 0.13 mmol/L)
4. Estimated GFR (>60 mL/min/1.72m²)
5. Urine protein (<30mg/day)

• Urea is a nitrogen-containing substance normally cleared from the blood by the kidney into the urine. Diseases that compromise the function of the kidney often lead to increased blood levels of urea.
• Creatinine is a chemical waste molecule that is generated from muscle metabolism. It is transported through the bloodstream to the kidneys, which then filter out most of the creatinine and dispose of it in the urine. Elevated creatinine level signifies impaired kidney function or kidney disease.
• Glomerular filtration is the process by which the kidneys filter the blood,removing excess wastes and fluids. EGFR is the best test to measure your level of kidney function and determine your stage of kidney disease.
• Being tested positive for urine protein means the presence of an excess of serum proteins in the urine. However, there is a basal level of urine protein that can occur below 30 mg/day which can be considered non-problematic.

Once you have have a normal kidney function baseline you may start on protein supplements with your doctor's advice, but do keep your kidney function in check during your yearly medical check-up. If you're not already doing it, now would be a good time to start.

For those interested to read the paper:

Dietary protein intake and renal function 

William F Martin, Lawrence E Armstrong and Nancy R Rodriguez 

Nutrition & Metabolism 2005, 2:25 

Abstract

Recent trends in weight loss diets have led to a substantial increase in protein intake by individuals. As a result, the safety of habitually consuming dietary protein in excess of recommended intakes has been questioned. In particular, there is concern that high protein intake may promote renal damage by chronically increasing glomerular pressure and hyperfiltration. There is, however, a serious question as to whether there is significant evidence to support this relationship in healthy individuals. In fact, some studies suggest that hyperfiltration, the purported mechanism for renal damage, is a normal adaptative mechanism that occurs in response to several physiological conditions. This paper reviews the available evidence that increased dietary protein intake is a health concern in terms of the potential to initiate or promote renal disease. While protein restriction may be appropriate for treatment of existing kidney disease, we find no significant evidence for a detrimental effect of high protein intakes on kidney function in healthy persons after centuries of a high protein Western diet.