Eating a handful of almonds a day substantially boosts the production of butyrate, a short-chain fatty acid that promotes gut health.
A team of scientists from King’s College London investigated the impact of consuming whole and ground almonds on the composition of gut microbes. The study was published recently in the American Journal of Clinical Nutrition. It was funded by the Almond Board of California.
The human gut microbiome consists of thousands of microorganisms living in the intestines. These play a vital role in digesting nutrients and can have a significant positive or negative influence on our health, including our digestive and immune systems. Although the mechanisms of how the gut microbiomes have an impact on human health are still being investigated, evidence indicates that eating specific types of food can positively influence the types of bacteria in our intestines or what they do in our gut.
Investigators recruited 87 healthy adults who snacked on typical unhealthy snacks (e.g. chocolate, chips) and who were already eating less than the recommended amount of dietary fiber. Participants were split into three groups: one group changed their snacks to 2 ounces (56 grams) of whole almonds a day, another to 2 ounces (56 grams) of ground almonds a day, and the control group ate energy-matched muffins as a control. The trial lasted four weeks.
“Part of the way in which the gut microbiota impact human health is through the production of short-chain fatty acids, such as butyrate. These molecules act as a fuel source for cells in the colon, they regulate absorption of other nutrients in the gut, and help balance the immune system.”
– Lead author Professor Kevin Whelan, Head of Department of Nutritional Sciences
Researchers discovered that butyrate was substantially higher among almond eaters compared to those who consumed the muffin. Butyrate, a short-chain fatty acid, is the main source of fuel for the cells lining the colon. When these cells function effectively, it provides ideal conditions for gut microbes to flourish, for the gut wall to be strong and not leaky or inflamed, and for nutrients to be absorbed.
No significant difference was observed in gut transit time – the time it takes for food to move all the way through the gut. However, participants who consumed whole almonds had an additional 1.5 bowel movements per week compared to the other groups. These results indicate that eating almonds could also benefit those with constipation.
Testing showed that eating whole and ground almonds improved peoples’ diets, having higher intakes of monosaturated fatty acids, fiber, potassium, and other important nutrients compared to the control group.
Professor Whelan added: “We think these findings suggest almond consumption may benefit bacterial metabolism in a way that has the potential to influence human health.”
Reference: “The Impact of Almonds and Almond Processing On Gastrointestinal Physiology, Luminal Microbiology and Gastrointestinal Symptoms: a Randomized Controlled Trial and Mastication Study” by Alice C Creedon, Eirini Dimidi, Estella S Hung, Megan Rossi, Christopher Probert, Terri Grassby, Jesus Miguens-Blanco, Julian R Marchesi, S Mark Scott, Sarah E Berry and Kevin Whelan, 20 September 2022, American Journal of Clinical Nutrition.