Nighttime Pistachios Reshape Gut Health in Prediabetes

New Study Reveals Significant Microbial Shifts

For millions grappling with prediabetes, controlling blood sugar is paramount, yet effective dietary strategies remain elusive. New research suggests that a simple bedtime snack – pistachios – may significantly alter the gut microbiome, offering a promising avenue for improving metabolic health.

Pistachios Impact Gut Bacteria

A study led by nutritional scientist **Kristina Petersen** found that adults with prediabetes who consumed approximately two ounces of pistachios nightly for 12 weeks experienced notable changes in their gut bacteria. These shifts occurred when pistachios replaced traditional carbohydrate-based snacks, such as whole-grain bread, often recommended for overnight glucose regulation.

“Pistachios seem to be able to meaningfully shift the gut microbial landscape in adults with prediabetes especially when consumed as a nighttime snack,” stated **Petersen**. She added that these alterations could potentially slow the onset of Type 2 diabetes or reduce inflammation.

“Good” Bacteria Flourish

Researchers observed a significant increase in beneficial bacteria, including species like Roseburia and members of the Lachnospiraceae family. These microbes are known for producing short-chain fatty acids, such as butyrate, which nourish colon cells and support anti-inflammatory processes.

The study, published in *Current Developments in Nutrition*, involved 51 adults and utilized a randomized crossover design. This method ensured that each participant experienced both the pistachio snack and the standard carbohydrate snack, allowing for direct comparison of their effects on the gut microbiome via stool sample analysis.

Detrimental Bacteria Decline

**Petersen** also noted a decrease in certain bacteria associated with poorer metabolic health. Levels of *Blautia hydrogenotrophica*, linked to kidney and heart health issues, were lower after pistachio consumption. Additionally, *Eubacterium flavonifractor*, which can break down beneficial compounds in foods, also decreased.

The findings align with previous research indicating that pistachios offer comparable blood glucose benefits to 15 to 30 grams of carbohydrates. However, the direct link between these microbiome changes and tangible health improvements requires further investigation, **Petersen** cautioned.

Broader Implications for Health

Prediabetes affects an estimated one-third of U.S. adults, with a high likelihood of progression to Type 2 diabetes. Interventions that target the gut microbiome, a critical regulator of glucose and inflammation, are therefore of significant interest.

The research team, including **Terrence Riley**, **Jordan Bisanz**, **Penny Kris-Etherton**, **Justin Wright**, **Regina Lamendella**, **Jeremy Chen See**, and **Khushi Kanani**, received funding from the American Pistachio Growers, Penn State, the National Institutes of Health, Juniata College, and the U.S. National Science Foundation. The study is registered at ClinicalTrials.gov (NCT04056208).