Meat Consumption, Cognitive Function and Disorders: A Systematic Review with Narrative Synthesis and Meta-Analysis

Abstract

Cognitive impairment, Alzheimer’s disease, and other forms of dementia are increasing in prevalence worldwide, while global dietary patterns are transitioning to a ‘western type’ with increasing meat consumption. Studies which have explored the associations between cognitive function and meat intakes have produced inconsistent findings. The aim of this systematic review was to explore the evidence linking meat intake with cognitive disorders. Twenty-nine studies were retrieved, including twelve cohort, three case-control, thirteen cross-sectional studies, and one intervention study. The majority (21/29) showed that meat consumption was not significantly associated with cognitive function or disorders. Meta-analysis of five studies showed no significant differences in meat consumption between cases with cognitive disorders and controls (standardized mean difference = −0.32, 95% CI: −1.01, 0.36); however, there was considerable heterogeneity. In contrast, a meta-analysis of five studies showed reduced odds of cognitive disorders by consuming meat weekly or more (OR = 0.73, 95% CI: 0.57, 0.88); however, potential publication bias was noted in relation to this finding. Overall, there was no strong association between meat intake and cognitive disorders. However, the evidence base was limited, requiring more studies of high quality to isolate the specific effect of meat consumption from dietary patterns to confirm these associations.

Diet and general cognitive ability in the UK Biobank dataset

“…Consistent with the results from previous reviews 7 , 22 , in the adjusted model, we showed the benefits of habitual consumption of fish and unprocessed red meat on general cognitive ability. As fish contains some essential macronutrients including protein and unsaturated fatty acids 23 and as unprocessed red meat is a good source of protein, and B group vitamins 24 , our findings could be explained by the positive associations observed with cognition and (i) B vitamins, (ii) n−3 fatty acids, (iii) proteins, and (iv) dietary patterns that are moderately high in protein (e.g.…”

Diet–Cognition Associations Differ in Mild Cognitive Impairment Subtypes

“…For other food items, meat consumption was generally considered to have an adverse effect on cognitive outcomes due to its high saturated fat content [ 47 , 48 ] which is potentially associated with the overproduction of circulating free fatty acids and systemic inflammation. However, the specific effect of meat consumption on cognitive disorders was often discordant [ 18 ]. A longitudinal study of a large cohort with a mean follow-up of 9.8 years and active ascertainment of dementia showed that low meat consumption (≤1 time/week) was associated with an increased risk of cognitive impairment compared with regular consumption (≥4 times/week) [ 8 ].…”

“…The increased consumption of fish or nuts was observed to reduce the risk of MCI [ 7 , 15 , 16 ], benefiting cognitive abilities. Few studies have examined the effect of staple foods [ 17 ] or meat [ 18 ] that are generally considered to have negative effects on health because of their high contents of carbohydrate or saturated fat. Most previous studies, however, tended to focus on the outcome of MCI, without data specifically on subtypes of MCI, including single domain/multidomain amnestic and non-amnestic subtypes [ 19 ], which feature as deficits of distinct cognitive domains related to unequal brain function and have varied prevalence.…”

Nutrition, Gut Microbiota, and Alzheimer's Disease

“…Moreover, low meat consumers also ate less fish, fruit and vegetables, therefore, they could have low dietary intake in general and some nutritional deficiencies (31). No strong association between meat consumption and cognitive decline was observed in the meta-analysis by Zhang et al (32).…”