Effects of Consumption of Nut Components on Cognitive Function, Intestinal Microbial Communities and Markers of Health
Condition: Cognitive Function; Urinary Metabolites; Intestinal Microbiota
Study type: Interventional

Summary: 
      Tree nuts (for example brazil nuts, almonds, hazelnuts, walnuts, cashew nuts etc) contain a
      wide variety of nutrients including fatty acids, polyphenols and micronutrients. The
      beneficial health effects ascribed to the consumption of tree nuts include improvements to
      cardiovascular outcomes and regulation of glucose levels and inflammation. Emerging evidence
      suggests that specific components of nuts may also contribute to brain health and function.

      The aim of the present study is to assess the effects of four weeks' supplementation of nut
      components on cognition and subjective measures. Urinary metabolites and intestinal microbial
      communities will also be assessed allowing biomarkers of nut exposure to be highlighted.
    

Detailed description: 
      To date, only two small human intervention trials have evaluated the effects of nuts as a
      sole intervention on cognition. One study reported a benefit verbal fluency and
      constructional praxis following daily consumption of 6 g brazil nuts for 6 months in older
      adults diagnosed with mild cognitive impairment. Eight weeks' consumption of 60 g/d walnuts
      in healthy young adults aged 18-25 years also resulted in improved inferential verbal
      reasoning scores compared to placebo.

      The development of various 'omics' technologies has enabled researchers to investigate the
      influence of nutrients or dietary change on metabolic pathways at multiple levels with a view
      to developing biological markers of dietary intake.

      Metabolomic approaches have been used successfully to study nut consumption; for example
      putative biomarkers of nut consumption have been revealed as metabolites associated with
      serotonin pathways. Furthermore, certain nut biomarkers identified using metabolomics appear
      to be negatively associated with health parameters which is suggested to be due to gut
      microbiota dysbiosis and provides an important link between nut consumption, the gut
      microflora and metabolic pathways.

      This study will assess the effects of four weeks' supplementation with nut components on
      cognition. Metabolomic and metagenomic approaches will be utilised to analyse urinary
      metabolites and intestinal microbial communities allowing biomarkers of nut exposure to be
      highlighted. Metabolic and gut microbiota responses will then be correlated with changes in
      cognition in order to identify inter-individual differences in response, and further
      understanding of the mechanisms underpinning cognitive benefits of nut consumption.
    

Intervention name(s): Nut components; Placebo
Intervention type(s): Other; Other
Intervention description(s): nut components consumed daily for a period of 28 days; Placebo consumed daily for a period of 28 days
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: 2 x 4 week intervention with 4 week washout
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Other
Keywords: Cognition; Metagenomics; Metabolomics