Peanuts as a nighttime snack enrich butyrate-producing bacteria compared to an isocaloric lower-fat higher-carbohydrate snack in adults with elevated fasting glucose: A randomized crossover trial

Clin Nutr. 2022 Oct;41(10):2169-2177. doi: 10.1016/j.clnu.2022.08.004. Epub 2022 Aug 13.


Background: Tree nuts have glucoregulatory effects and influence gut microbiota composition. The effect of peanuts on the microbiota has not been investigated.

Objectives: The aim was to examine the effect of 28 g/d of peanuts for 6-wks, compared to an isocaloric lower-fat higher-carbohydrate (LFHC) snack, on gut microbiota composition. A secondary aim was to identify functional and active compositional differences in a subset of participants using metatranscriptomics.

Methods: In a randomized, crossover trial, 50 adults (48% female; 42 ± 15 y; BMI 28.3 ± 5.6 kg/m2; plasma glucose 100 ± 8 mg/dL) consumed 28 g/d of dry roasted, unsalted, peanuts (164 kcal; 11% E carbohydrate, 17% E protein, 73% E fat, and 2.4 g fiber) or a LFHC snack (164 kcal; 53% E carbohydrate, 17% E protein, 33% E fat, and 3 g fiber) for 6-wk (4-wk washout period). Gut bacterial composition was measured using 16S rRNA sequencing in the whole cohort. Exploratory metatranscriptomic analyses were conducted on a random subset (n = 24) of samples from the Peanut condition.

Results: No between-condition differences in α- or β- diversity were observed. Following peanut intake, Ruminococcaceae were significantly more abundant [Linear discriminant analysis score (LDA) = 2.8; P = 0.027)] compared to LFHC. Metatranscriptomics showed increased expression of the K03518 (aerobic carbon-monoxide dehydrogenase small subunit) gene following peanut intake (LDA = 2.0; P = 0.004) and Roseburia intestinalis L1-82 was identified as a contributor to the increased expression.

Conclusion: An increased abundance of Ruminococcaceae was observed following consumption of 28 g/d of peanuts in adults with elevated fasting glucose after 6-wks. Metatranscriptomics revealed increased expression of the K03518 gene. These results suggest peanut intake enriches a known butyrate producer and the increased expression of a gene implicated in butyrate production adds further support for peanut-induced gut microbiome modulation. NCT: 03654651.

Keywords: Diet quality; Glucose; Gut microbiota; Peanuts; Short chain fatty acids.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Arachis* / genetics
  • Arachis* / metabolism
  • Bacteria
  • Blood Glucose / metabolism
  • Butyrates
  • Carbon / metabolism
  • Cross-Over Studies
  • Fasting
  • Glucose / metabolism
  • Humans
  • Oxidoreductases / metabolism
  • RNA, Ribosomal, 16S / genetics
  • Snacks*


  • Blood Glucose
  • Butyrates
  • RNA, Ribosomal, 16S
  • Carbon
  • Oxidoreductases
  • Glucose