Investigation into the effect of almond consumption on ectopic fat, endothelial function and other cardiometabolic disease risk factors

: an observational study and a randomised controlled trial in UK adults

Abstract

Background: Suboptimal dietary patterns associated with many snack foods, typically high-fat, high-refined carbohydrate foods, that are low in fibre and nutrients, present an easily identifiable target to improve cardio-metabolic health.Meta-analyses of epidemiological and interventional studies have reported that almonds are associated with lower intermediary risk of CVD. However, tree nut and almond consumption levels are unknown in the UK population, and the impact of almond snack consumption on endothelial function and liver fat, as key drivers of CVD, remains unclear.

Aim: 1) to investigate the prevalence of tree nut/almond consumption and its association with diet quality and CVD risk in the UK adult population, and 2) to study the effects of snacking on tree nuts, specifically whole almonds, on CVD risk markers, including endothelial function and liver fat as main outcomes, and other metabolic risk factors, in displacement of typical snacks.

Methods: In cross-sectional analysis using the UK National Diet and Nutrition Survey (NDNS) data from adult respondents(≥19y), the average consumption of almonds was determined and its association with intermediary CVD risk markers, including body composition and fasting blood lipids using analysis of covariance (ANCOVA) adjusted for covariates was explored. Following a 2-week run-in period consuming control snacks, a 6-week parallel arm trial was undertaken where participants were randomized to isoenergetic treatments: 1) control snacks (mini-muffins) replicating the UK average snack nutrient profile; or 2) dry-roasted whole almonds, providing 20% estimated energy requirement. Endothelial function (via flow-mediated dilation (FMD)), liver fat (via MRI/1H-MRS), heart rate variability (HRV) and other risk measures were assessed at baseline and endpoint. A total of 107 participants (75F,32M; mean age 56.2y, SD 10.4) were randomized and 105 completed the trial.

Date of Award	1 Nov 2020
Original language	English
Awarding Institution	King's College London
Supervisor	Wendy Hall (Supervisor) & Sarah Berry (Supervisor)