Low-carb improves pancreatic function and type 2 diabetes

A new study shows a lower-carb, higher-protein diet improves glucose control and pancreas function more than a standard diet for type 2 diabetes. And perhaps more importantly, the study showed these benefits in the absence of weight loss.

Several studies published over the past few years show that low-carb nutrition helps treat and even reverse type 2 diabetes. Much of the benefit has been presumed to be due to diet-induced weight loss that typically corresponds with improved insulin sensitivity and reduced hyperinsulinemia.

But could low-carb diets have unique benefits, aside from weight loss, that also improves pancreatic beta-cell function? A new study from Denmark suggests that they can.

Type 2 diabetes is a multifaceted disease process with insulin resistance and hyperinsulinemia, eventually leading to pancreatic beta-cell failure and insulin insufficiency.

The study randomized 28 individuals with type 2 diabetes to eat either a diet with 30% of energy from carb and 30% of energy from protein, or a diet with 50% of energy from carb and 17% of energy from protein. After six weeks, participants crossed over to the other diet.

Remarkably, the researchers provided all meals for the course of the study. That’s a lot of meals! And it is a fantastic way to improve diet consistency and compliance.

The diets were matched for calories and were designed to limit weight loss. Caloric matching eliminates the “real world” natural calorie reduction that usually accompanies low-carb diets. However, it allows a direct comparison of the effect of macronutrient content independent of weight loss.

Just as we have seen in other studies, the lower-carb, higher-protein diet resulted in significantly improved postprandial and 24-hour glucose readings.

What makes this study stand out is that the results also showed improved pancreatic beta-cell sensitivity and function. This is where it gets a little complicated.

There was no difference in fasting insulin levels between the groups, but the authors went further and measured pancreatic sensitivity markers, such as the proinsulin to insulin ratio. While these measurements are new to most people, the authors detail in the paper how these markers are well recognized as measurements of pancreatic function and sensitivity. Most of these markers significantly improved in the lower-carb group.

This study concludes that independent of weight loss, a 30% carb 30% protein diet:

1. improves glucose control
2. improves insulin sensitivity
3. improves pancreatic beta-cell function
4. improves satiety
5. decreases liver and pancreas fat

The study doesn’t indicate whether the main factor causing improvement was the lower carb level or the higher protein level; it is possible that both play a part in the positive changes seen. However, the study does demonstrate that a “high protein” diet — in this case, one with 30% of calories coming from protein — is not harming glucose and insulin control.

This study gives us hope that lower-carb, higher-protein diets can improve type 2 diabetes by improving insulin sensitivity and pancreatic function, independent of weight loss. That’s an essential step in understanding how diet can reverse type 2 diabetes and restore health.

Thanks for reading,
Bret Scher, MD FACC

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