Walnuts contribute to the reproduction of bacteria beneficial for the intestines, MedicalXpress reported referring to scientists from the University of Pennsylvania.
The scientists conducted a study with 42 volunteers with overweight. Before the start of the experiment, all of them followed the so-called American diet for two weeks – they ate a lot of fats and carbohydrates. Then they were randomly divided into three groups depending on the new diet. The first group was set to eat whole walnuts, the second group was to take an equivalent amount of alpha-linolenic acid (ALA) and polyunsaturated fatty acids without walnuts, and the third group should have took ALA, partially replaced by oleic fatty acid, but also without walnuts.
After six weeks researchers collected samples of intestinal bacteria 72 hours before the end of the preliminary American diet, as well as during the experiment.
Walnuts contributed to the growth of beneficial intestinal bacteria, such as Roseburia, which protect the intestinal lining. The bacterial content of Eubacterium eligens, which may be useful for normalizing blood pressure, has also increased. Walnuts have contributed to an increase in the number of Lachnospiraceae bacteria that help significantly lower blood pressure, total cholesterol and low density lipoprotein cholesterol.
Serious changes in the composition of intestinal bacteria were not found in people from two other groups.