Fourth Summit on Yogurt (Proceedings in Journal of Nutrition)

What’s the effect of yogurt on blood glucose?


Yogurt has a much lower impact on glucose levels than people think. Therefore, it gets the green light to be included in a diabetes-friendly diet. In fact, research has shown that diets including yogurt may even help to reduce the risk of developing type 2 diabetes (T2D).
One explanation is associated to glycemic index of yogurt, which was the aim of the presentation of Thomas Wolever (University of Toronto, Canada) at the Fourth Global Summit on the Health Effects of Yogurt.

Most yogurts have a minimal effect on blood sugar

The differences between carbohydrate foods can be described in relation to their glycemic index. Simply put this index, which goes from 100 to 0, indicates how quickly a food raises blood glucose levels. Glucose is rated at 100, and the closer to 100 a food is rated, the more it increases blood sugar levels. Generally, GI values of foods are classified as low GI(GI≤55), medium GI (55<GI<70) and high GI (GI≥70).

Wolever looked at 93 GI values for yogurt from the database of the GI values of foods published online by the University of Sydney. None of them were classified as high GI food, and the majority (92 %) enter the low GI category, whatever the sugar content (GI = 27 and 41 respectively for plain and sweetened yogurt). Recent research has provided evidence that diets with a high GI are associated with an increased risk of T2D. Choosing low GI foods allows people to reduce the GI of the diet, which may reduce the risk of developing T2D.

Yogurt swaps can change the game

Why does yogurt have a low GI? The author explores several aspects that could explain this asset. One of suggested explanation is that during the fermentation process, lactic acid is formed, and it may reduce glycemic response by slowing gastric emptying. Another stronger suggestion stipulates that the varying amounts of fat and protein, nutrients, which are known to reduce glycemic response, could also play a role. Protein content shows stronger effect on lowering glycemic response than fat do.

Indeed, Wolever notes that the 43 plain yogurts analyzed have a lower GI than the 50 sweetened yogurts. However, this difference is not explained by sugar, but rather by the protein-to-carbohydrate ratio, higher for plain yogurt. As yogurt has a lower GI than most other carbohydrate foods, the authors conclude that swapping yogurt for other protein and carbohydrate sources can reduce the GI of the diet, and is also in line with recommended dietary patterns.

Want to learn more about yogurt science and gut microbiota? Discover our next story here

Source: Wolever T MS. The Journal of Nutrition. First published June 14, 2017.