When studying metabolic status and its association with the microbiota composition, it was found that the amount of cardiovascular risk factors correlated with the predominance of the opportunistic [9
genus, the number of which was significantly (adj. p
< 0.001) higher in patients with a greater number of risk factors.
3.3.6. Diet and Gut Microbiota
Among bacteria associated with clinical parameters, Blautia (associations with first grade arterial hypertension, DM-2) abundance was significantly associated with resistant starch consumption (adj. p = 0.007). Notably, high consumption of cholesterol, as well as of alcohol, was strongly associated with a lower abundance of Bifidobacterium (adj. p = 0.008 and 0.006, respectively).
To analyze dietary habits, the subjects were divided into two clusters using the k-medoid algorithm with Bray–Curtis distance matrix, calculated from the percentage of proteins, fats and carbohydrates in the donors’ diets according to food frequency questionnaires. The first cluster contained 64 samples, the second, 22.
These clusters were significantly different in relation to the percentage of proteins, fats and carbohydrates in the donors’ diets (p < 0.001 for each nutrient). The first dietary cluster was characterized by a greater proportion of carbohydrates in the diet, the second by a greater proportion of fats and proteins. In the second dietary cluster, the proportion of samples from donors with newly diagnosed DM-2 was two times greater (15.6% in the first cluster and 32% in the second cluster).
The dietary clusters were not differentiated by age, gender or BMI of their subjects (p = 0.5, 0.25, 0.4, respectively). In the second dietary cluster, a difference between samples from healthy donors and donors with DM-2 was found in the Prevotella genus abundance (higher in the DM-2 group, adj. p < 0.001). However, the trend was not obvious, possibly due to a wide spread in the nutrient composition of the diet (for example, donors with impaired glucose metabolism in the second diet cluster consumed more calcium (p = 0.03)). Therefore, a similar method of searching for optimal dietary clusters was used, but the number of clusters was determined by the Calinski–Harabasz index, in order to identify samples with more similar diets. Ten clusters were identified.
Donors in one of the clusters had a very similar diet, consuming a lot of fats, although half of them had normal glucose metabolism and the other half were newly diagnosed with DM-2. There were no differences in age, gender or quantity of consumed calories between these two groups (p = 0.8, 0.5 and 0.3 respectively), nor in other nutritional features.
GML analysis showed that Blautia
genus abundance (adj. p
= 0.0001) was higher in the samples from donors with DM-2, which is consistent with previous analyses [6