Soy protein hydrolysate shows promise for weight management
compared to carbohydrate, and when the protein is eaten before
carbs the glucose response may be blunted.
The research, published in the journal Metabolism , could tap into the burgeoning weight loss and management market, estimated to already be worth $7bn (€5.2bn) globally.
It also has implications for diabetes.
With 50 per cent of Europeans and 62 per cent of Americans classed as overweight, the food industry is waking up to the potential of products for weight loss and management.
The slimming ingredients market can be divided into five groups based on the mechanisms of action - boosting fat burning/ thermogenesis, inhibiting protein breakdown, suppressing appetite/ boosting satiety (feeling of fullness), blocking fat absorption, and regulating mood (linked to food consumption).
The new study, by Mandy Claessens and co-workers from Maastricht University and Kerry Bio-Science, tested the effect of SPH on diet-induced thermogenesis (DIT) and glucose, glycogen, and insulin response with and without a carbohydrate pre- and afterload.
Claessens and co-workers recruited eight healthy non-obese men (average age 28.5, average weight 75.9 average BMI 23.3 kg per sq. m) to take part in the single-blind crossover study.
The test was divided into five trials and required to drink beverages (250 mL) containing SPH, carbohydrate, and SPH with carbohydrate as pre- or afterload.
Beverages contained 0.4 grams of protein or maltodextrin.
The researchers report that consumption of the SPH beverage produced a higher DIT than carb beverage, with similar insulin responses produced by both beverages.
The protein beverage resulted in an increase in the glucagon, but not glucose, response, while the carb drink induced a glucose, but not glucagons, response.
Thermogenesis and insulin responses were not significantly different when the carb beverage was consumed before or after the protein drink.
Interestingly, drinking the SPH drink before the carb drink blunted the glucose reponse associated with the maltodextrin.
"This study shows that the larger DIT after protein than after carbohydrate may be related to the glucagon response that is induced by protein but not by carbohydrate; that the protein-induced DIT and glucagon response are not influenced by a carbohydrate pre- or afterload; and that protein ingestion can fully prevent the plasma glucose increase associated with carbohydrate when carbohydrates are ingested after proteins," wrote the researchers.
"The finding that protein ingestion before carbohydrate prevents the carbohydrate -induced increase in blood glucose is of interest in view of the discussion about glycemic index and its effect on health because this condition may allow ingestion of high-glycemic index carbohydrates without the associated high blood glucose response," they added.
"To find out how protein/peptide preloads influence plasma glucose levels over 24 hours or over longer periods, long-term studies with high-protein diets should be performed," concluded Claessens.
Source: Metabolism (Elsevier) August 2007, Volume 56, Issue 8, Pages 1051-1059 "The thermogenic and metabolic effects of protein hydrolysate with or without a carbohydrate load in healthy male subjects" Authors: M. Claessens, W. Calame, A.D. Siemensma, W.H.M. Saris, M.A. van Baak
