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Walnut consumption and health outcomes with public health relevance—a systematic review of cohort studies and randomized controlled trials published from 2017 to present.
- Source :
- Nutrition Reviews; Jan2023, Vol. 81 Issue 1, p26-54, 29p
- Publication Year :
- 2023
-
Abstract
- Context Considering the accumulation of recent studies investigating the health effects of walnut consumption, both including and beyond cardiovascular health effects, a systematic review of this literature to investigate the strength of the evidence is warranted. Objective To investigate associations between walnut consumption and outcomes with public health relevance (specifically all-cause mortality, type 2 diabetes, CVD, metabolic syndrome, obesity, cancer, neurological and mental health, musculoskeletal, gastrointestinal, and maternal disorders) and the effect on associated disease risk markers, reported in studies published from 2017 to present. Data Sources MEDLINE, FSTA, CENTRAL, and Scopus were searched from 1 January 2017 to 5 May 2021. Data Extraction Human studies (cohort studies and RCTs) ≥3 weeks in duration comparing consumption of walnuts (whole, pieces, or 100% butter) to a control and measuring associations with relevant public health outcomes and disease risk markers were assessed. Key study characteristics were extracted independently by 2 investigators using a standardized table. The quality of the studies was assessed using the Cochrane Risk-of-Bias tool 2.0 and the Newcastle–Ottawa Scale. Data Analysis Only 1 RCT was considered to be at low risk of bias for any of its outcomes. The cohort studies were considered to be of moderate or high quality. The results were synthesized using vote counting, based on the direction of effect. Thirty-three articles, 23 describing RCTs (walnut dose ∼10–99 g/day, 1,948 subjects) and 10 describing cohort studies (∼675,928 subjects), were included. Vote counting could be performed for the blood lipids, cardiovascular function, inflammation- and hemostatic-related factors, markers of glucose metabolism, and body weight and composition outcome groupings. The results are presented in effect direction plots. With respect to blood lipids, results from 8/8 RCTs favoured walnuts, in accordance with associations with a reduced risk of CVD suggested by cohort studies; results from 6/6 RCTs favoured control with respect to body weight and composition, although most of these effects were small. This was contrary to cohort study results suggesting small benefits of walnut consumption on body weight. There was no overall consistent direction of effect for cardiovascular function, markers of glucose metabolism, or inflammation- and hemostatic-related factors. Conclusions Evidence published since 2017 is consistent with previous research suggesting that walnut consumption improves lipid profiles and is associated with reduced CVD risk. Evidence is accumulating in other areas, such as cognitive health, although more research is needed to draw firm conclusions. Systematic Review Registration PROSPERO registration no. CRD4202122. [ABSTRACT FROM AUTHOR]
- Subjects :
- EVALUATION of medical care
BIOMARKERS
ONLINE information services
MEDICAL databases
OBESITY
MUSCULOSKELETAL system diseases
CARDIOVASCULAR diseases risk factors
CONFIDENCE intervals
BODY weight
WALNUT
SYSTEMATIC reviews
MORTALITY
GUT microbiome
PUBLIC health
CARDIOVASCULAR diseases
GASTROINTESTINAL diseases
RANDOMIZED controlled trials
COMPARATIVE studies
TYPE 2 diabetes
OXIDATIVE stress
RESEARCH funding
QUALITY assurance
METABOLIC syndrome
AGING
MEDLINE
TUMORS
LONGITUDINAL method
MENTAL illness
LIPIDS
Subjects
Details
- Language :
- English
- ISSN :
- 00296643
- Volume :
- 81
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Nutrition Reviews
- Publication Type :
- Academic Journal
- Accession number :
- 160777768
- Full Text :
- https://doi.org/10.1093/nutrit/nuac040