Prediabetes affects a third of the US, and most of them develop type 2 diabetes, but effective dietary intervention strategies are still limited. While pistachios have shown promise in improving markers of dietary quality, little is known about how they affect intestinal microbiomes. It is an important player in glucose regulation and inflammation.
A new study led by Pennsylvania's associate professor of nutrition science, Christina Petersen, determined that nighttime pistachio consumption affects gut bacteria in adults with prediabetics. According to Petersen, the potential therapeutic implications of the findings remain unknown, but they may prove important to those working to improve metabolic health.
Findings published in the Journal Current Developments in Nutrition suggested that replacing traditional carbohydrate-based bedtime snacks with pistachios could potentially reshape the gut microbiome. Previous studies by these researchers have demonstrated that pistachios have similar effects as 15-30 grams of carbohydrates.
“A common dietary recommendation for pre-diabetics is to consume nighttime snacks, consisting of 15-30 grams of carbohydrates, to help regulate blood sugar levels overnight and morning.” “As an example, you can eat one or two slices of whole grain bread.”
Researchers observed that consuming about 2 ounces of pistachios each night for 12 weeks significantly differed in the profile of the hairy microbial community compared to those who consumed the recommended 15-30 grams of carbohydrate snacks. Certain bacteria groups, including members of the Lacnospira family, known as “good” bacteria that produce beneficial short-chain fatty acids, such as Roseburia and butyric acid, were more abundant following the pistachio state.
According to Petersen, butyric acid acts as the main source of energy for colon cells, maintains bowel barriers and supports anti-inflammatory processes.
“Pistachios appears to be able to meaningfully change the gut microbial landscape of diabetic adults, especially when consumed as a nighttime snack,” Petersen said. “These microbiome changes may offer other long-term health benefits, which may help slow the onset of type 2 diabetes or reduce systemic inflammation.
The effect of the first part of the study had no effect on Part 2, as 51 pre-diabetic adults were involved and conducted over two 12 weeks separated by breaks. By the end of the study, all participants received both treatments. Stool samples were collected and analyzed using 16S RRNA gene sequencing, a technique useful for classifying bacteria based on stool composition.
Petersen noted that participants who ate pistachios also experienced a decline in several bacterial groups associated with less favorable metabolic outcomes.
“The levels of hypertrophy – a bacteria that helps produce compounds that accumulate in the blood and can harm kidney and heart health – low after consumption of pistachio,” Petersen said. “The levels of Eubacterium flavonifixer, which break down beneficial antioxidant compounds in foods like pistachios, have also been reduced.”
Petersen added that the intensity of this study is the design used – in a randomized crossover clinical trial, all participants receive both treatments in a randomized order. By including all participants in the pistachio group and standard care group, this study helped researchers better understand how certain foods, such as pistachio, affect the gut microbiota.
This study showed alterations in intestinal bacteria, but it remains unclear whether these changes will be directly converted to improved health. This is a question that needs further research, Petersen said.
Jordan Bissanz, assistant professor of biochemistry and molecular biology in Pennsylvania. Penny Kris-Etherton retired as professor of nutrition science in Pennsylvania. Justin Wright, LLC from Light Lab. And Regina Ramendera, Jeremy Chen Si and Khushi Kanani of Junior Tae University all contributed to this study.
The study was funded by American Pistachio Growers, the Institute for Clinical Sciences in Pennsylvania State through the National Center for Advancement of Translation Science, through the National Institutes of Health, with additional support from Junior College and the National Science Foundation. Registered on ClinicalTrials.gov (NCT04056208).
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