The findings of the study, Acute and second-meal effects of peanuts on glycaemic response and appetite in obese women with type 2 diabetes risk: a randomized cross-over clinical trial, published in the British Journal of Nutrition, are good news for everyone and especially people who are overweight and who are at higher risk of diabetes.
The joint American-Brazilian team of investigators led by Dr Richard Mattes of Purdue conducted a three-phase study using meals containing 42.5g of either peanuts, peanut butter, or no peanuts or peanut butter (the control group). These were consumed by a rigorously selected group of 15 women aged 18-50 who all had BMIs >30, making them clinically obese, as part of a breakfast consisting of orange juice and cream of wheat cereal, followed by a high refined carbohydrate lunch consisting of white bread and strawberry jam.
In the study, blood samples and appetite ratings were taken over a series of three hours following breakfast and again after lunch to assess glucose (blood sugar) control and satiety (feelings of fullness). Peanut butter or peanuts eaten at breakfast were found to promote secretion of the appetite-suppressing hormone peptide YY (PYY). Participants who consumed peanut butter or peanuts reported a lower desire to eat for up to 8-12 hours later, and maintained lower blood sugar following a high carbohydrate lunch compared to participants that did not include peanut butter or peanuts.
Peanut butter had a slightly stronger satiety effect. This is possibly due to the processing of peanut butter which ruptures peanut walls and this may help slow the rate that carbohydrates are absorbed from the gut, resulting in a lower glycaemic response in the blood. That was particularly beneficial for this group of obese women who are at increased risk of type 2 diabetes and who need help with bodyweight management while maintaining their blood sugar levels.
The investigators suggested that the nutrient benefits of peanuts were synergistic, with their high protein, high fibre and healthy fats all helping to maintain blood sugar control as well as contribute to feelings of fullness.
Peanuts contain more protein by weight per 100g than any other nut and they are good sources of fibre.
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