A reader asked what I thought of a recent report which hit all the major news networks. The title of the report is: Low Protein Intake Is Associated with a Major Reduction in IGF-1, Cancer, and Overall Mortality in the 65 and Younger but Not Older Population. Click here to get your copy.
My first thought was: "What were the animal proteins these people were eating? Grain-fed or grass-fed? They are not the same."
Since the report was pretty heady stuff, I searched around and found this interesting comment.
A 24 hour dietary recall was used to classify subjects and then they were followed for 18 years. Is it possible their diets changed over that time
Next, the work in humans was correlative and observational. It was not an intervention or controlled study. All we can conclude is there is a relationship
Most importantly is the authors statistical analysis of the data and their interpretation. If we look at the raw data we see that the rate of cancer across the low, medium, and high protein groups was actually 9.8, 10.1, and 9.0%, respectively. There is no difference. However, the authors did some funky math to come up with this huge difference
In mice, there was no difference in the rate of cancer growth between the vegan protein (soy) and the animal protein (casein); however, the authors claim there was a "non-significant trend" but they do not report the probability value. If we look at the graph, it is barely discernible and does not exceed the standard deviation
Why then might the researchers make their conclusions off this lack of evidence? Its quite simple, the senior researcher, V. D. Luongo is the founder and has equity in L-Nutra, a Vegan Based Nutrition System. Luongo designed the study, obtained funding, and played a major role in the writing of the manuscript. This is a serious conflict of interest, and we should hold the publisher of the study, Cellular Metabolism, and their peer reviewers responsible for not identifying these issues. If you want to read more about it you can here at my objective critical analysis.
I strongly suggest that you read the man's more in-depth critical analysis to understand how "reports" must be evaluated. In addition, for more information about the advantages of a protein diet I also recommend this book.
Thursday, March 20, 2014