Summary: Consuming a handful of almonds each day increases butyrate production, improves bacterial metabolism, and positively influences health.
Font: King’s College London
A team of King’s researchers investigated the impact of whole and ground almonds on the composition of gut microbes.
The study, published today in the American journal of clinical nutritionis funded by the California Almond Board.
The gut microbiome consists of thousands of microorganisms that live in the gut. These play a vital role in the digestion of nutrients and can have a positive or negative influence on our health, including our digestive and immune systems.
The mechanisms of how gut microbiomes impact human health are still being investigated, but evidence suggests that eating specific types of food can positively influence the types of bacteria in our gut or what they do in our gut.
The researchers recruited 87 healthy adults who already ate less than the recommended amount of dietary fiber and ate typical unhealthy snacks (eg, chocolate, potato chips).
The participants were divided into three groups: one group swapped their snacks for 56 g of whole almonds per day, another for 56 g of ground almonds per day, and the control group ate energy-matched muffins as a control. The trial lasted four weeks.
“Part of the way the gut microbiota affects human health is through the production of short-chain fatty acids, such as butyrate. These molecules act as a fuel source for colon cells, regulate the absorption of other nutrients in the gut and help balance the immune system,” said lead author Professor Kevin Whelan, Head of the Department of Nutritional Sciences. .
The researchers found that butyrate was significantly higher among those who ate almonds compared to those who ate muffins. Butyrate is a short-chain fatty acid that is the main source of fuel for the cells that line the colon.
When these cells are working effectively, they provide an ideal condition for intestinal microbes to flourish, for the intestinal wall to be strong from leaking or inflamed, and for nutrients to be absorbed.
No significant difference was seen in intestinal transit time, the time it takes for food to move through the entire intestine; however, the whole almond eaters had an additional 1.5 stools per week compared to the other groups. These findings suggest that eating almonds might also benefit people with constipation.
The tests showed that eating whole and ground almonds improved people’s diets, with higher intakes of monounsaturated fatty acids, fiber, potassium and other important nutrients compared to the control group.
Professor Whelan added: “We think these findings suggest that almond consumption may benefit bacterial metabolism in a way that has the potential to influence human health.”
About this news on diet and microbiome research
Author: Kevin Whelan
Font: King’s College London
Contact: Kevin Whelan – King’s College London
Image: The image is in the public domain.
original research: Open access.
“The impact of almonds and almond processing on gastrointestinal physiology, luminal microbiology, and gastrointestinal symptoms: a randomized controlled trial and chewing study.by Kevin Whelan et al. American journal of clinical nutrition
Summary
The impact of almonds and almond processing on gastrointestinal physiology, luminal microbiology, and gastrointestinal symptoms: a randomized controlled trial and chewing study.
Background
See also
Almonds contain lipids, fiber, and polyphenols and possess physicochemical properties that affect the bioaccessibility of nutrients, which are assumed to affect gut physiology and microbiota.
Objectives
To investigate the impact of whole almonds and ground almonds (almond flour) on faecal bifidobacteria (main outcome), gut microbiota composition, and transit time.
Design
Healthy adults (n = 87) participated in a 3-arm parallel randomized controlled trial. Participants received whole almonds (56 g/d), ground almonds (56 g/d), or an isocaloric control muffin instead of their usual snacks for 4 weeks. Gut microbiota composition and diversity (16S rRNA gene sequencing), short-chain fatty acids (gas chromatography), volatile organic compounds (gas chromatography, mass spectrometry), intestinal transit time (wireless motility capsule), Stool output and bowel symptoms (7-day diary) were measured at baseline and endpoint. The impact of almond shape on particle size distribution (PSD) and predicted lipid release was measured in a subgroup (n = 31).
Results
A modified intention-to-treat analysis was performed on 79 participants. There were no significant differences in fecal bifidobacteria abundance after consumption of whole almonds (8.7%, SD 7.7%), ground almonds (7.8%, SD 6.9%) or control (13.0% , SD 10.2%; what = 0.613). Consumption of almonds (whole and ground pooled) resulted in higher amounts of butyrate (24.1 μmol/g, SD 15.0 μmol/g) compared to control (18.2 μmol/g, SD 9, 1 µmol/g; p = 0.046). There was no effect of almonds on the gut microbiota at the level of phylum or diversity, gut transit time, stool consistency, or gut symptoms. Almond form (whole versus ground) had no effect on study results. Ground almonds resulted in significantly lower PSD and higher predicted lipid release (10.4%, SD 1.8%) compared to whole almonds (9.3%, SD 2.0%; p = 0.017).
Conclusions
Almond consumption has a limited impact on the composition of the gut microbiota, but increases butyrate concentrations in adults, suggesting positive alterations in the functionality of the microbiota. Almonds can be incorporated into the diet to increase fiber intake without triggering intestinal symptoms.
