Almonds pegged as beneficial snack for gut health and immunity in King’s College London study

20 Oct 2022 --- Almond consumption can lead to significant butyrate – a form of beneficial short-chain fatty acid (SCFA) – increases and greater stool frequency, resulting in beneficial changes to the gut microbiota’s functionality. This is according to a recent UK-based King’s College London study funded by the Almond Board of California, US.

“These findings indicate almonds can be incorporated into the diet of healthy adults to potentially boost the production of an important bacterial metabolite called butyrate,” Dr. Alice Creedon, post-doctoral researcher, Department of Nutritional Sciences at King’s College London, tells NutritionInsight.

“Butyrate is involved in several health-promoting processes such as providing energy to the cells lining the gut, regulation of the immune system and signaling to the cells of the gut to absorb certain nutrients.”

According to the researchers, almonds were well tolerated and did not cause any gastrointestinal symptoms, suggesting that eating them can be a safe strategy to boost fiber intake.

Healthy snacking and increasing fiber levels
The findings also inform consumers that almonds can be added to the diet of adults who typically consume below the recommended level of fiber without triggering bothersome gut symptoms, as is often the case when high-fiber foods are added to the diet of these individuals, Creedon explains. 

She continues: “In terms of the nutrition industry, these findings indicate almonds could be better marketed for their role as a healthy snack food.”

“Due to the effect of almonds on increasing butyrate production, they could be promoted as a snack food that can be consumed to benefit gut health by targeting bacterial metabolism.”

According to Creedon, the results show that almond processing (to almond flour) does not alter the effect of almonds on the gut, indicating both whole almonds and almond flour as potential sources of gut health promoting fiber and polyphenols for fortifying cereals and other food products.

Due to almonds’ ability to increase butyrate production, they may be marketed as a snack food that improves gut health by focusing on bacterial metabolism.“Almonds may also increase stool frequency, which could benefit those suffering from constipation, but this requires confirmation in future trials,” she underpins.

Inflammation and colon cancer
The researchers note that the primary fuel source for colonocytes – the cells that line the colon – is butyrate, which is created by microbes in the gut when they digest fiber.

Butyrate may be involved in several processes that affect human health, including enhancing sleep and reducing inflammation and has been linked to a lower risk of colon cancer.

“These findings are exciting as they demonstrate that almonds may increase an important health-promoting metabolite (butyrate),” says Creedon.

“The team is currently working on trials that will further explore this effect of almonds, as well as investigating the impact of almonds on our immune system and mental health.”

Whole and ground almond impact
The researchers set out to determine the impact of whole almonds and ground almonds on gut microbiota composition, diversity and transit time.

In healthy adults, eating almonds does not significantly impact the number of fecal bifidobacteria, other gastrointestinal microbiota, gastrointestinal transit, pH, pressure, stool quantity or gut symptoms. 

Almonds would, therefore, probably be well tolerated if added to the diets of low-fiber consumers in the general population to boost fiber intake. Consuming almonds may impact the Lachnospiraceae family and certain aspects of bacterial metabolism, particularly fecal butyrate.

Investigating fecal SCFAs and stool output
The research was based on 87 healthy adult participants, both male and female, between the ages of 18 and 45, who reported regularly consuming two or more snacks daily.

Participants underwent comprehensive screening for exclusion criteria and ate a regular diet with less fiber than advised.

The research included groups of 29 individuals each. The first group received 56 g of whole almonds daily (approximately 2 oz). In comparison, group two received 56 g of ground almonds daily (almond flour), and the control group consumed two energy-balanced snack muffins daily.

Participants consumed their study snacks for four weeks instead of their regular snacks. With each snack, they drank at least 100 ml of water.

Fecal SCFAs, whole-gut transit time, gut pH, stool output (both frequency and consistency), the relative abundance of fecal bifidobacteria, fecal microbiota composition and diversity and gut symptoms were among the outcomes that were measured.

Analysis of the fecal microbiota revealed no significant baseline differences in phyla or genera between bacteria groups. Furthermore, compared to the control snack, almonds, whether whole or ground, did not enhance the amount of fecal bifidobacteria.

By Nicole Kerr