Carbohydrate is an essential part of our diets, but not all carbohydrate foods are equal. The Glycemic Index (GI) is a way of measuring the effects of food on blood sugar. Carbohydrate-containing foods with a low GI value (55 or less) are digested, absorbed and metabolized more slowly. They cause a lower and slower rise in blood glucose and therefore in insulin levels. Consuming low GI carbohydrates helps to reduce the risk of developing type 2 diabetes, and to facilitate the management of diabetes, its complications and other chronic lifestyle diseases.
Protein and lactose help to regulate blood sugar
With a glycemic index value of 55 or less, milk and dairy foods are considered to be low-glycemic. Foods with a value between 56 and 69 exert a moderate effect on blood sugar levels. High-glycemic foods are assigned a value of 70 to 100 and trigger the most rapid rise in blood glucose. Yogurt has a specifically low GI, which means that the rise in blood glucose, after eating a yogurt, is lower, compared to many other foods or snacks. Why is that so? Yogurt (plain: 27 (GI) and sweetened: 41 (GI)) has an overall low GI, due to its lactose and protein content.
How do we explain the difference between both types of yogurt? According to Wolever, sweetened yogurts contain about 2,5 times more carbohydrate per 100g than plain yogurts. Since GI is measured, by using portions of food containing equal amounts of carbohydrate, the amount of plain yogurt, containing 25g carbohydrate, has about twice as much protein, as the amount of sweetened yogurt, containing 25g carbohydrate. Adding dairy protein to carbohydrate, reduces therefore glycemic responses in a dose-dependent fashion, which accounts for almost the exact difference in GI between plain and sweetened yogurts.
Insulin response doesn’t matter
Relative to other carbohydrate foods, dairy foods, like yogurt, cause surprisingly a disproportionately high insulin response, by reducing hepatic insulin extraction. A high insulin response is generally considered to be deleterious, because hyperinsulinemia is associated with insulin resistance and increased risk for T2D. Nevertheless, a high intake of yogurt products does not increase the risk for type 2 diabetes, despite the fact that yogurt elicit a disproportionately high insulin response, relative to their glycemic impact. In addition, yogurt, whether consumed alone or as a part of mixed meals, likely elicits similar or lower insulin response than other meals/snacks. Therefore, Wolever concluded that choosing yogurt instead of other protein and carbohydrate sources, as part of a healthy dietary pattern, may assist in reducing the diet GI and therefore the risk for T2 diabetes.
Key-learnings
- Yogurt is associated with a reduced risk for T2D
- Low diet GI is associated with a reduced risk for T2D
- Yogurt has a low GI, mainly due to its lactose and protein content
- Plain yogurt (GI = 27) < artificially sweetened yogurt (GI = 41), due to higher content of protein per carbohydrate
- There are few data on the insulinemic impact of yogurt
- Even assuming that yogurt causes a high insulin response, because of its high protein content, when consumed alone or as a part of mixed meals, it will likely elicits similar or lower insulin response, compared to other meals/snacks.
- Yogurt can replace other foods, as a healthy way to reduce diet GI and to reduce the risk of developing T2D.
