Can Whey Protein Control Blood Sugar?

Researchers from Israel believe people with diabetes could benefit from this protein-rich beverage.


You have seen the advertisements—overly muscular body builders tauting the health benefits of one or more high-protein drinks. Although you may not be in training for the Mr. or Mrs. America contest, whey-protein drinks have been found to be helpful for people with type 2 diabetes.

When consumed before breakfast, whey protein shakes can help prevent the blood sugar fluctuations that are common after meals, says Israeli researchers from Tel Aviv University. If left unchecked (continuous and long-term), these erratic variations in blood sugar can cause serious issues over time—worsening diabetes, cardiovascular disease, and damaging the retina of the eye.  

In fact, people with diabetes who drank the whey protein drink before breakfast saw a 28% drop in after-meal glucose scores, reported the authors of the study published in Diabetologia.1

The researchers evaluated the effectiveness of whey protein, a nutrient-rich byproduct from cheese production, against a mock product on 15 patients with well-controlled Type 2 diabetes. Some of the patients drank a protein drink containing 50 grams of whey protein, mixed with 250 milliliters of water, while the other patients consumed a placebo.

They then ate a standard, high-glycemic-index breakfast as researchers monitored their glucose, insulin, and incretin levels over an entire 3-hour post-meal period. The patients were only taking a sulfonylurea, which increase insulin production from the pancreas, or metformin, which suppresses the liver from producing too much glucose. 

Interestingly, the glucose levels weren't the only signs of improvement; Insulin response more than doubled (105%) while C-peptide responses spiked by 43%, noted the researchers.1

How it Works

So why does whey protein seem so effective? The reason behind this lies in its ability to stimulate secretion of glucagon-like peptide-1 (GLP-1). This potent intestinal hormone is one of the body's most essential tools for lowering blood glucose levels, said Dr. Daniela Jakubowicz and colleagues, authors of the study.

Consequently, when patients drank whey protein their GLP-1 levels soared, doubling and tripling the numbers; total GLP-1 and intact GLP-1 rose by 141% and 298%, respectively. It is known that protein ingestion will increase GLP-1 secretion, so the premise behind the study was to evaluate how beneficial it could be to blood glucose levels.

These results present valuable new insight into how a simple, commonplace protein could be a "novel approach for enhancing glucose-lowering strategies in Type 2 diabetes," Dr. Jakubowicz and colleagues said.

After seeing the spikes in GLP-1, though, Dr. Jakubowicz and colleagues now faced a new question: How exactly is this happening?

In previous research, Dr. Jakubowicz suggested this is caused by how the gastrointestinal system digests whey protein.

As the body breaks down the whey, amino acids and bioactive peptides must be created, stimulating cellular activity in the intestine that causes GLP-1 and other necessary incretins to secrete more, Dr. Jakubowicz said.2

Another explanation has to do with DPP-4, an enzyme that inhibits GLP-1.3

They expected to see this enzyme's activity diminish. This would explain why GLP-1 suddenly rocketed in its numbers, but interestingly, DPP-4's numbers didn't show that.

Whether the patients were drinking whey or just a placebo, they all had similar DPP-4 activity.

"This would suggest that altered inactivation of GLP-1 by whey protein is not executed through changes in plasma DPP-4 activity," said Dr. Jakubowicz and colleagues.

This, of course, lends room for speculation. Dr. Jakubowicz and colleagues postulate that whey protein is internally inhibiting DPP-4. This would explain why GLP-1 levels rose so much, but it's not a new idea.

Eight years ago, researchers made the same conclusions after performing metabolic tests on mice.4

So there are more questions to be answered, like how GLP-1 plays its role in aiding insulin response for patients with Type 2 diabetes.

In the meantime, key recommendations for individuals with diabetes to maintain their health still include:

  • Regular physical activity
  • Choosing healthy meal options while maintinaing consistency in the amount of carbohydrates are eaten at meals to reduce post-meal blood glucose rise
  • Taking medications as prescribed
  • Monitoring blood glucose levels at various times throughout the day to assess meal and medication effects.

The research was funded by the Israeli Ministry of Health and Milk Council.

Updated on: June 22, 2016