Some benefits seen in both groups
The patients in the study were a mean age of 71 and had been in a prediabetic state for an average of 4.8 years at the beginning of the study. They were 55% male and there were no other significant differences in characteristics between the groups.
While the conversion from being prediabetic to type 2 diabetes in the adult population has been reported to be about 10.6%, and the risk has been observed to be even higher in the 65 and older population, rates were lower than that in both groups.
“At the end of our 1-year study, we observed a [rate of] new-onset type 2 diabetes of 2.7% and 5.2% in the sardine group and control group, respectively,” the authors note. They add the differences were not statistically significant.
Both the sardine consumption and control groups showed significant reductions in A1c versus baseline (P = .011 and P = .010, respectively), as well as significant reductions in glucose fasting concentrations (P = .020 and P = .040, respectively).
And while the sardine group showed greater improvements in HDL versus the control group (P = .045), only the control group showed a significant decrease in total cholesterol versus baseline (P = .032).
Both groups showed improvements in the management of body weight, body mass index, and waist and hip circumference, in addition to improvement in body composition – despite no physical activity components in the programs, the authors note.
“This is probably because both groups followed the same base type 2 diabetes-preventive diet, with the one exception of sardine supplementation, and, although they did not modify their physical activity, both groups reduced their daily caloric intake through food,” the authors note.
The possibility of reducing diabetes risk through dietary changes as opposed to weight loss is especially important in the older population, the authors note, as some studies suggest a link between weight loss in the elderly and an increased risk of mortality.
In a second phase of the study, the researchers say they are evaluating the effect of sardines on the intestinal microbiota, “since it affects the regulation of many biological processes, and we need to understand if they have played a part in this protective effect against type 2 diabetes,” Dr. Díaz-Rizzolo concluded.
The study was funded by RecerCaixa 2013. The authors report that “no industry sponsorship was received for this work that could have influenced its outcome.”
A version of this article first appeared on Medscape.com.