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Almonds & Gut Health: The Research

Research shows that eating almonds is associated with positive gut health attributes, and the latest study findings suggest almonds may help benefit some gut microbiota functionality.


The gut microbiome refers to the community of microorganisms, including bacteria and other microbes, that live in our gastrointestinal tract and play a crucial role in many bodily functions, including digestion, metabolism, immunity, and brain function. Maintaining a healthy gut microbiome is essential for overall well-being, and eating a balanced, fiber-rich diet helps increase microbiome diversity to support better health. Research on the link between almonds and gut health is growing, and results from several studies indicate that almond consumption may benefit the gut microbiome and overall gut health.  

In one study1, researchers found that incorporating a morning almond snack in the dietary regimen of predominately breakfast-skipping college freshmen improved the diversity and composition of the gut microbiome. The researchers looked at gut microbiome diversity and abundance among those who had a morning snack of almonds versus those who ate graham crackers. Those in the almond group had a 3% greater quantitative alpha-diversity and an 8% greater qualitative alpha-diversity than the cracker group after the intervention. Increased bacterial richness is associated with favorable health outcomes, such as glucose tolerance and insulin sensitivity. The fiber, monounsaturated fats and polyphenol content of almonds are likely responsible for the greater alpha-diversity, according to the researchers.

Another study found that overall, almond consumption increased the relative abundance of specific beneficial bacteria in the gut. This study was designed to measure the metabolizable energy of different almond forms2 and researchers collected fecal samples that were later analyzed to track changes in gut microbiota. A group of 18 healthy adult men and women consumed 1.5 servings (43g) of either whole almonds, roasted almonds, chopped almonds or almond butter every day for a three-week period. Participants repeated this for each almond form, and fecal samples were collected at the end of each three-week period. The researchers suggest that the fiber and polyunsaturated fatty acids found in almonds may be partly responsible for modulating the composition of the gut microbiome.

Almond Consumption May Benefit Some Gut Microbiota Functionality, Study Finds

A study from King’s College London3 set out to determine the impact whole almonds and ground almonds have on the composition of gut microbiota, gut microbiota diversity and gut transit time.

Led by Professor Kevin Whelan, the study found that consuming almonds significantly increased butyrate, a type of beneficial short-chain fatty acid (SCFA), in the colon. Butyrate, which is produced by microbes in the gut when they digest fiber, is the primary fuel source for colonocytes, the cells that line the colon, and may play a role in multiple processes related to human health, including improving sleep quality and fighting inflammation, and has been associated with a lower risk of colon cancer.4,5The study also found that almond consumption significantly increased stool output, which is associated with a well-functioning gastrointestinal system.

How do almonds impact your gut health?

Here’s everything you need to know about this new study:

Study Participants:

The study comprised healthy adult volunteers (75 females, 12 males), average age 27.5 years, who were regular snackers, and who were consuming a typical diet that was lower in fiber than recommended.

Study Design:

Participants were randomly assigned to a group, each comprising 29 participants; group one received 56 g/day (about 2 oz./day) of whole almonds, group two 56 g/day (about 2 oz./day) of ground almonds (almond flour), and the control group ate energy-matched snack muffins (two per day). Participants were required to eat their study snacks instead of customary snacks, and they did this twice a day for four weeks. They drank at least 100 mL water with each snack.

Study Results:

The study found that participants who consumed whole and ground almonds experienced significant increases in butyrate as well as increased stool frequency. Almonds were well tolerated and did not lead to gastrointestinal symptoms, which indicates almond consumption may be a way to increase fiber without causing any adverse effects. This is suggestive of positive alterations to microbiota functionality.


Limitations of this study are seen in both the sex distribution of volunteers, where more than 86% were female, as well as in age. Average age of participants was 27.5 years. The researchers recognize their findings are not necessarily generalizable to males or to older populations.

Looking Into the Future of Almonds and Gut Health Research

Given the promising findings, more research is in the works to look at the impact almonds have on gut health and to help improve our knowledge in the area.

Feeding Your Gut with Nutrients

Several nutrients naturally found in almonds—fiber, polyunsaturated fatty acids and polyphenols—are thought to be responsible for the potential benefits relating almonds to improvements in gut microbiota. One serving (28 g) of almonds has 13 g of unsaturated fat and only 1 g of saturated fat, 4 g fiber, and essential nutrients, including: 77 mg (20%DV) magnesium, 210 mg (4%DV) potassium, and 7.27 mg (50%DV) vitamin E, making them a nutrient-rich snack.

While promising, it’s important to remember that gut health in general is an area of study still in its infancy—there is more to discover and more to understand. Although findings from these initial studies on almonds are promising, further research is warranted.

1. Dhillon, J., Li, Z., & Ortiz, R. M. (2019). Almond snacking for 8 wk increases alpha-diversity of the gastrointestinal microbiome and decreases Bacteroides fragilis abundance compared with an isocaloric snack in college freshmen. Current Developments in Nutrition, 3(8). 10.1093/cdn/nzz079


2. Holscher, H. D., Baer, D. J., et al. (2018). Almond consumption and processing affects the composition of the gastrointestinal microbiota of healthy adult men and women: A randomized controlled trial. Nutrients, 10(2), 126. 10.3390/nu10020126


3. Creedon, A. C., Dimidi, E., Hung, E. S., Rossi, M., Probert, C., Grassby, T., Miguens-Blanco, J., Marchesi, J. R., Scott, S. M., Berry, S. E., & Whelan, K. (2022). The impact of almonds and almond processing on gastrointestinal physiology, luminal microbiology and gastrointestinal symptoms: A randomized controlled trial and mastication study. American Journal of Clinical Nutrition, 116(6), 1790-1804.


4. Koh, A., De Vadder, F., Kovatcheva-Datchary, P., & Backhed, F. (2016). From dietary fiber to host physiology: Short-chain fatty acids as key bacterial metabolites. Cell, 165(6), 1332-1345. 10.1016/j.cell.2016.05.041


5. Szentirmai, E., Millican, N. S., Massie, A. R., & Kapas, L. (2019). Butyrate, a metabolite of intestinal bacteria, enhances sleep. Scientific Reports, 9:7035, 1-9.