Whey lowers the glycemic index

Adding whey—found in milk and also available as a nutritional supplement—to a high-carbohydrate meal may help people with diabetes keep blood sugar levels under control.

In the study, researchers from Sweden and Denmark compared the effects of eating a high glycemic index meal with or without whey supplementation on blood sugar levels after the meal.

For two days, 14 people with diet-treated type II diabetes ate a high-glycemic index breakfast of white bread followed by a high-glycemic lunch of mashed potatoes and meatballs.

A whey supplement containing 18.2 grams of protein mixed in water was added to both meals on one day. On another day, subjects ate the same meals with lean ham and lactose dissolved in water in place of the whey supplement.

Researchers took blood samples before and after the meals and found that insulin levels were higher after the whey-supplemented meals.

For example, insulin levels were 31% higher after the high-glycemic index breakfast and 57% higher after the high-glycemic index lunch when whey was included compared with when it was not. The study also shows that the rise in blood sugar levels after lunch were reduced by 21% with whey supplementation.

Milk is known to have an insulinotropic effect, which means that it affects the production and activity of insulin. Researchers think that this is because of the whey found in milk. Liquid protein also exits the stomach faster and is digested more rapidly than a solid protein, which may explain the higher insulin response.

Reference
Frid AH, Nilsson M, Holst JJ, Bjorck IM. (2005). Effect of whey on blood glucose and insulin responses to composite breakfast and lunch meals in type 2 diabetic subjects. American Journal of Clinical Nutrition, 82, 69-75