Feed the (wo)man diabetes

As I wrote in another article, Eating meat: the fast track to diabesity, epidemiological (population-study) evidence strongly points to meat consumption as a major contributing factor to obesity and diabetes.

Epidemiological studies, however, can only suggest, not prove, a cause-and-effect relationship; until a ‘smoking gun’ that shows a mechanism of action is found, the ideas generated by epidemiological research are just hypotheses.

Well, in the case of animal protein consumption as a contributor to diabetes risk, that smoking gun has been found, and it bears the decidedly unsexy title of ribosomal protein S6 kinase 1.

First, a little bit of background on the epidemiological studies:

• The EPIC-PANACEA study (which involved nearly 400 000 European men and women) found that the more red meat, processed meat and poultry people consumed, the more weight they gained over the 5 year study period (1), even if their energy (kilojoule/calorie) intake was lower than those who ate less meat!
• A meta-analysis of 12 studies on meat consumption and diabetes (2) found that high intake of meat of any kind increased the risk of developing type 2 diabetes by 17% compared to low meat intake; high intake of red meat by 21%; and high intake of processed meat by 41%.
• The Adventist Health Study found that eating a vegetarian diet reduced the risk of developing metabolic syndrome, a precursor to diabetes, by a whopping 56% (3), while a vegan diet slashed the risk of developing diabetes itself by nearly 50% (4).

And now we can turn our attention to the studies which spell out exactly how excess protein – the component of animal foods that most people think is so good for them – causes insulin resistance, the metabolic defect that leads to type 2 diabetes.

A person suffering from insulin resistance has more insulin circulating in their bloodstream than a ‘normal’ person, but their insulin does not work properly. As a result, their cells have reduced ability to take up glucose from the bloodstream and burn it as a fuel, leaving them with a sustained high blood glucose level that contributes to elevated blood pressure, cholesterol and triglycerides, heart disease and fatty liver.

Over time, insulin resistance can progress to type 2 diabetes.

Firstly – and in direct contradiction to the claim made by advocates of high-protein diets, that carbohydrates make you fat because they stimulate insulin release while protein does not – it’s been know for many decades that amino acids (the building blocks of protein) are responsible for roughly 60% of the rise in insulin levels after a meal (5).

Intake of protein causes a 360% larger insulin spike in obese people compared to those of normal weight (6), suggesting that excess protein intake is even more dangerous if you’re already overweight.

Secondly, the branched chain amino acids leucine, isoleucine and valine, which cause the biggest spikes in insulin after a meal, are found in higher amounts in animal proteins – especially in whey protein (7), which is one of the two protein types found in milk, not to mention the main ingredient in those enormous tubs of protein powder beloved of body builders!

Thirdly, and this is where ribosomal protein S6 kinase 1 (S6K1 to its friends) comes in, excess amino acids in the bloodstream – the simple consequence of eating too much protein – activate S6K1, which in turn activates a protein called mTOR (mammalian target of rapamycin – a protein involved in insulin signalling) in an abnormal way, causing insulin resistance (8).

So the ‘smoking gun’ linking excess protein intake to diabetes is that the amino acids in protein cause insulin resistance to develop. The fact that vegans have a dramatically lower risk of diabetes than meat-eaters indicates that the particular pattern of amino acids found in plant proteins does not cause insulin resistance, however.

So, next time your personal trainer, neighbour, colleague or other self-appointed expert on nutrition tells you that ‘carbs’ cause diabetes and you should be on a high-protein diet to prevent it, grab this golden opportunity to look REALLY smart: ask them how on earth it is that they don’t know that amino acids negatively affect insulin signaling through class 3 PI3K, or hVps34 mediation of mTOR/S6K1 phosphorylation of IRS1. That should stop them dead in their tracks :).

Are you diabetic or pre-diabetic? Do you have a family history of diabetes? Would you like expert guidance in constructing and adopting the ultimate diabetes prevention and reversal diet?

Having lost several of my close family members to type 2 diabetes, I have a particular passion for diabetes prevention and reversal. Become an EmpowerEd member today to get in-depth information and guidance on how to become, or remain, a non-diabetic.