Youth and sedentary lifestyle

A team of researchers from the University of Valparaíso carried out an unprecedented study that concluded that the consumption of fresh blueberries provides relevant benefits in the glycemic control of young but sedentary people.

The research, carried out by the academics of the School of Nutrition and Dietetics of the University of Valparaíso Ximena Palma and Samanta Thomas, together with Dr. Gonzalo Cruz, of the Center for Neurobiology and Integrative Physiopathology (CENFI) and academic of the Institute of Physiology of the UV , aimed to evaluate postprandial glucose management (after meals) and the antioxidant capacity of fresh blueberries.

Natural food

The study published in Nutrients, a major open access scientific journal in the area of ​​nutrition, explains that “blueberries are fruits rich in polyphenols with antioxidant and anti-inflammatory properties. Berry polyphenols work by blocking digestive enzymes, remodeling gastrointestinal microbiota pathways, and affecting the release of gastrointestinal hormones to regulate insulin dynamics and glucose management. However, most studies use fruit extracts instead of fresh fruits. We aimed to evaluate postprandial glucose management and the antioxidant capacity of fresh blueberries consumed acutely or as a six-day supplementation in ten sedentary subjects.

The researcher Ximena Palma, Master in Biological Sciences with a mention in Nutrition, explains that "it was important to be able to use natural foods and not extracts, concentrates or supplements, because I have always been in favor of taking advantage of the composition of foods, especially unprocessed foods, to obtain benefits over health. And that's why we wanted to see if there was any effect on glycemic control when consuming a serving of natural blueberries, which is super feasible on a day-to-day basis."

Blueberry effect

The researcher adds that “We tried two ideas: the effect of a single serving of blueberries in conjunction with high carbohydrate intake, and also the effect after consuming an equal-sized serving of the same fruit for six days. By consuming them raw, and not processed, we can obtain a higher concentration of those water-soluble compounds, such as polyphenols and vitamin C, since these could be lost to some degree when subjected to cooking or dehydration, for example. We can also ensure a higher concentration of antioxidant compounds, since if you break the food matrix, for example, you can expose these substances to environmental oxygen and reduce their concentration; and dietary fiber, which, although it was not the objective of our research, also has various health benefits, which could be diminished by turning the fruit into juice or jam, for example."

The results of the study indicated that the consumption of fresh blueberries improves glucose management after meals (postprandial), presumably due to actions in the gastrointestinal tract, while supplementation improves insulin sensitivity, probably due to antioxidant and anti-inflammatory effects.

Beneficial features

For Dr. Gonzalo Cruz, who directs the CENFI Reproductive and Metabolic Alterations Laboratory, it is important to consume foods rich in polyphenols due to their anti-inflammatory and antioxidant effect and the content of dietary fiber, especially berries.

“Polyphenols can block the enzymes that digest carbohydrates and thus, for better glycemic control, it would be preferable to even consume them before carbohydrates or perhaps at the same time. In the study we show that the consumption of a cup of 'berries' manages to reduce the increase in glucose that is observed when consuming white bread”.

Along the same lines, Dr. Cruz anticipates that “in the case of lunch, vegetables and salads could also be consumed before the main course, in order to take advantage of the nutrients and have the effect produced by polyphenols on glycemia. Or also eat the 'berries' for dessert, but before lunch”.

Chile, largest exporter

Until last year, Chile was the largest exporter, and second largest producer, of fresh blueberries in the world, which Ximena Palma sees as an excellent opportunity, since "blueberries are fundamentally known for being rich in antioxidants, but few people knows that polyphenols (the antioxidants we studied) can also modulate other physiological processes, such as digestion and consequent absorption of carbohydrates, insulin secretion and inflammation, among others. If we can promote and make these effects known, I am sure that people would be more interested in their consumption”.

PhD Science, Mention Research and Development of Bioactive Products, Samanta Thomas, points out that "it is surprising that a single serving of 150 grams of blueberries was responsible for decreasing the area under the postprandial glucose curve and increasing insulin secretion fifteen minutes after intake. In other words, it produced an acute or immediate response of extremely important metabolic parameters in glycemic control”.