Emergent Fitness: Low Protein Intake Associated with Lower Risk of Cancer? I Think NOT!

A recent study seems to contradict everything I've said regarding the non-harmful effects of animal proteins. I now stand before the Vegetarian Inquisition. Time to be a man and defend myself!

The Article: "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" (Link Here)

The Major Theses of the Paper

If you follow the link to the article (found above), you'll readily note the highlights of the article -

High protein intake is linked to increased cancer, diabetes, and overall mortality
High IGF-1 levels increased the relationship between mortality and high protein
Higher protein consumption may be protective for older adults
Plant-derived proteins are associated with lower mortality than animal-derived proteins

It seems I've got some work to do.

Addressing Thesis 1

The first conclusion the authors of this study make seems awfully similar to the contention that Campbell makes in The China Study. If you've been following my series on vegetarianism wherein I've been breaking down Denise Minger's very thorough critique of Campbell's work, you well know of the impossibility of indicting protein (especially animal sources of protein) as if the term "protein" somehow could sufficiently encompass all of the various sources of amino acids in existence.

Speaking of animal proteins in particular, we already know that the source, and the type of protein from that source, will drastically effect how our bodies react. For instance, casein protein, which comes from milk, has carcinogenic properties when it is consumed in an environment where other toxins are already present - i.e. when we consume casein along with aflatoxin (which is rampantly prevalent in peanuts). Whey protein, however, which also comes from milk, has anti-carcinogenic properties.

So, as we can see, we make a rather big mistake when we categorize all animal sources protein into a single group. The authors of this particular study make this mistake. They broadly categorize all sources of protein as either animal or plant based. As the vigilant reader will easily note, certain sources of animal protein don't necessarily represent the panacea of health foods. I'm of course referring here to processed "franken-meats" (Oscar-Meyer anyone?).

Something else to keep in mind is that the average American (oh yeah! Did I mention that the authors based their study on "average" Americans, not health conscious omnivores) consumes, not only a plethora of processed meats, but also a variety of processed grain and flower products, along with a variety sugary goods, with these meats - i.e. buns, Doritos, soft drinks, etc. Such foods likely contributed to the increased risk of cancer mortality among the higher protein groups which the authors examined.

Addressing Thesis 2

So what is IGF-1? It is merely a shorthand name for insulin-like growth factor 1. Like its name suggests, IFG-1 is like insulin. Thus, like insulin, it is an anabolic hormone, related to, among many things, muscle growth and the supply of nutrients to various cells.

You may now ask: "If IGF-1 is like insulin, and insulin is spiked by carbs, why are we talking about protein?"

Good question! In reality, carbohydrates are not the only nutrients which effect insulin. Protein, too, will spike insulin, and also IGF-1. So what's so bad about it? Like any hormone in your body, IGF-1 is good when in the context of balance. Your body produces a variety of hormones for various biological and survival reasons. In the proper quantity, these hormones keep you alive and thriving. In the wrong quantities, they can be chronic stressors.

Intermittent fasting can actually lower IGF-1.

In this particular study, unnaturally high levels of IGF-1 seem correlative with increased risk of mortality. However, is this increased level related to excess protein consumption, or the actual health of the study participants prior to the test? IGF-1, interestingly enough, is related to a high body mass index. Since we've already established that the group in this study which consumed the highest amount of animal protein was also likely consuming other processed junk foods, and, moreover, since we may readily say that such foods are hyper-palatable and thus conducive to over-consumption, the reason the higher protein group had higher levels of IGF-1 was likely due, much in part, if not totally, to the overall poor quality of their diet. Animal protein, as a broad categorization, likely had nothing to do with the results the authors observed.

Addressing Thesis 3

I actually agree with this component of their study. I've read some interesting research (though I can't find it at the moment) that suggests that, as people age, their ability to efficiently metabolize dietary protein degrades. As a result, older individuals may likely need to consume higher quantities of protein in order for them to more easily hold on to their lean mass. However, as a caveat, one can also more readily hold on to, and build, lean mass by doing some form of intelligently designed resistance training program, even in the context of a low protein diet (Read this article I wrote for more info about this issue - Click Here).