Jordi Salas-Salvadó is a professor of Human Nutrition and Bromatology for the Faculty of Medicine and Health Sciences at the Rovira i Virgili University in Spain. He is well known for his expertise in obesity, type 2 diabetes mellitus, metabolic syndrome and cardiovascular disease. Read here part II of the interview.
How can yogurt intake play a role in weight management, as obesity is an important mediator for Type 2 Diabetes?
Dairy consumption has been studied extensively for its possible roles in body weight regulation. Epidemiologic studies indicate that dairy products, and in particular yogurt, may have the potential to reduce the risk of obesity. In addition, limited findings suggest that yogurt may have a more powerful effect on weight and body fat than other dairy foods, but further randomized controlled trials are needed to confirm this. Potential mechanisms for these findings are unclear, although evidence suggests that the consumption of dairy products, and specifically yogurt, may facilitate body weight and fat loss because dairy products contain calcium, protein — mainly casein and whey — and other bioactive compounds that may favorably affect energy balance. For example, one hypothesis is that dietary calcium plays a critical role in the regulation of body weight by affecting adipocyte intracellular calcium concentration, decreasing fatty acid synthesis while increasing lipolysis, leading to decreased triacylglycerol storage. Another possible mechanism is the inhibition of fat absorption in the intestine, because calcium interacts with free fatty acids to form calcium –fatty acid soaps. The formation of these insoluble complexes increases fecal fat excretion. Finally, it has also been suggested that probiotics from yogurt beneficially influence the inflammatory/anti-inflammatory balance of gut microbiota, which might mediate the lower risk of presenting overweight/obesity, but more research is needed in this regard.
In your study about the benefits of yogurt for the incidence of Type 2 Diabetes, why did you focus specifically on an older population?
Some studies recently reported a strong inverse association between dairy consumption, especially low-fat dairy consumption, and incidence of type 2 diabetes in healthy young adults and middle-aged individuals. However, to our knowledge, no studies have evaluated the effect of dairy consumption in elderly individuals at high cardiovascular risk. Importantly, elderly population is in higher risk of nutritional deficits. Therefore, increasing diary consumption, specially yogurt, by older adults could represent a convenient and economical strategy to enhance their intake of key macronutrients and micronutrients for this age group. Furthermore, yogurt has a relatively long shelf-life, and there are no obstacles in consumption for individuals with chewing difficulty. Last but not least, lactose intolerance is relatively prevalent in older population, thus yogurt is a convenient option due to its lower lactose content, in contrast to other dairy products.
You have examined the Mediterranean diet in particular, is there a difference in the role of yogurt compared to the Western diet? And how is yogurt related to a healthy lifestyle?
Historically, yogurt is a traditional component of Mediterranean, Middle Eastern, and South Asian gastronomies. Overall, although typical Western and Mediterranean diets can have a similar total dairy products content, the dairy products included in the Mediterranean Diet tend to be lower in fat, and specially are in yogurt form. In fact, we concluded, that a healthy dietary pattern incorporating a high consumption of low-fat dairy products and particularly low-fat milk and both low-fat and whole-fat yogurt may be protective against diabetes in older adults at high cardiovascular risk. Interestingly, some authors found that when yogurt consumption was jointly studied with healthy nutritional patterns such as a high consumption of fruit, the beneficial association was even more apparent.
On the other hand, although the relationship is unknown, it has also been reported that those consuming an average of 2.3 servings yogurt per week were more likely than non-consumers to eat more healthy foods, including fruit, vegetables, nuts, fish, and whole grains, and had a smaller proportion of their energy intake from processed meat, refined grains, and beer. Similarly, in our study, individuals who consumed higher amounts of dairy also consumed higher amounts of other foods, such as fruit, legumes, and lower amounts of total meat, fish, nuts, and alcohol, which might also have an impact on diabetes risk. However, the apparently protective relationship of dairy on diabetes persisted in multivariate models that accounted for dietary variables.