Forget the biscuits and crisps; the secret to a healthier gut and reduced inflammation might be found in a humble green nut eaten before bed. Recent scientific studies are pointing to pistachios as a nutritional powerhouse, with specific benefits for our gut bacteria, especially when consumed in the evening.
The Science Behind the Snack
A US study involving 51 adults, published in the journal Current Developments in Nutrition in July 2025, found that consuming pistachios at night positively altered gut bacteria. This effect, however, was notably observed in adults with pre-diabetes. The research suggested that swapping a carbohydrate-based snack like toast for a serving of pistachios could help reshape the gut microbiome—the complex community of microbes residing in our intestines.
Backing this up, a separate 2023 study in the journal Foods concluded that pistachios are more effective than other nuts at increasing the population of beneficial bacteria in the gut.
Why Pistachios Are a Gut Health Superstar
So, what gives pistachios their gut-boosting edge? According to experts, it's their unique nutritional profile. Dr Federica Amati, head nutritionist at ZOE, told The Independent that these nuts are packed with fibre and polyphenols, which act as premium fuel for our gut microbes. “Think of them as feeding the good bacteria that help keep your gut happy,” she explained.
Registered nutritionist Rob Hobson elaborated further, noting that the dietary fibre and specific carbohydrates in pistachios function as prebiotics. “They feed beneficial gut bacteria such as Bifidobacteria and Lactobacillus,” he said. When these fibres ferment in the colon, they produce vital short-chain fatty acids like butyrate, which are known to maintain a healthy gut lining, reduce inflammation, and support immune function.
Beyond fibre, pistachios release other beneficial compounds including polyphenols, tocopherols (a form of Vitamin E), and the antioxidant lutein. Mr Hobson confirmed that these compounds are metabolised by gut microbes, directly influencing the composition and activity of our microbiota.
Making the Simple Switch for Better Health
The combination of healthy fats and protein in pistachios also plays a crucial role by slowing digestion. This allows the nutrients to travel further down the gut to where fermentation occurs, thereby helping to balance the entire microbiome.
Choosing a handful of pistachios over conventional evening snacks is a double win. It not only provides these proven prebiotic benefits but also lowers your intake of sugar and salt, which can be detrimental to gut health. “Unlike high-risk snacks, pistachios don’t contain added sugars or emulsifiers that can disrupt your microbiome,” Mr Hobson concluded. “Having a handful of pistachios as a snack or sprinkling them on your meals is a simple and delicious way to support your gut health.”
