That was the key finding of a study conducted by the Chinese Centre for Disease Control and Prevention, Shanxi Centre for Disease Control and Prevention, Linyi Centre for Disease Control and Prevention, Duke University, and Beijing Union University.
Previous studies have often linked dietary patterns to cognitive function, but the finer details of these associations have not been completely understood.
Consumption and cognition
The researchers therefore conducted a cross-sectional study to explore the dietary patterns linked to cognitive function among older adults in underdeveloped regions, assessing 1,504 community-dwelling older adults aged 60 and above.
They used a food frequency questionnaire 24-hour dietary recall to evaluate the participants’ diets, factor analysis to extract their dietary patterns, and the Mini-Mental State Examination (MMSE) to assess their global cognitive function.
They subsequently identified two dietary patterns: a mushroom, vegetable and fruit (MVF) pattern, and a meat and soybean product (MS) pattern; both patterns were "significantly positively associated" with improvements in cognitive function.
The MVF pattern included some of the components found in the Mediterranean diet, which has been reported by multiple studies to be able to help lower the risk of Alzheimer's disease, as well as "pre-dementia syndromes and their progression to overt dementia".
The pattern was also consistent to a certain extent with several other dietary patterns that have been linked to better cognitive function, including those characterised by high fruit, wholegrain, fresh dairy, vegetable, nut and fish intake.
The antioxidant and anti-inflammatory properties of fruits and vegetables have been said to show protective effects on cognition, with a cohort study even suggesting that frequent mushroom consumption was "significantly associated with cognitive function because of the natural, free radical scavengers and antioxidant and anti-inflammatory effects in mushrooms".
Additionally, higher total long-term nut consumption was linked to slightly improved cognitive performance, possibly because of the interaction of the nutrients and other bioactive components of nuts.
When it came to the MS pattern, the researchers stated that despite red meat traditionally being associated with deteriorating cognitive performance, particularly in the elderly, evidence to the contrary has emerged.
While some studies have found no relationship between high meat intake and global cognitive function, the current study suggested that the MS pattern could protect against cognitive impairment.
This may be due to the nutritious components of lean red meat, such as protein, iron, and monounsaturated and polyunsaturated fatty acids.
Additionally, greater consumption of soy products and fish has also been linked to better cognitive function.
Despite its positive effects on cognitive function, however, the MVF pattern was also found to be related to a greater prevalence of diabetes and hypertension, likely due to the higher salt intake in the MVF dietary pattern.
Unlike Westerners, the Chinese typically boil or stew vegetables with salt, which is a highly important risk factor for both hypertension and diabetes.
Still, the researchers wrote that "since diet can influence cognition through more than one pathway, the positive effect of the MVF dietary pattern for cognitive function may outweigh its negative effect".
In terms of the inconsistencies observed in the relationship between the MS dietary pattern and cognitive function, a possible explanation is the study differences in total energy intake, as well as tools used to evaluate cognition, and sample size.
The study participants were from economically underdeveloped areas, characterised by a mean low daily energy intake of just 1,500kcal daily (1,602kcal for men and 1,392kcal for women). This was much lower than their Hong Kong and Japanese counterparts who had been assessed in other studies.
In fact, over 80% of the subjects did not meet the Chinese Nutrition Association’s energy intake recommendations, leading the researchers to say the study's results supported "the importance of energy intake for cognitive function".
This was consistent with previous studies that had shown how crucial both quality and quantity were when it came to dietary impact on cognitive performance, with a slightly lower energy intake associated with better cognitive function.
The researchers concluded: "Both the MVF and MS patterns were positively associated with cognitive function among older adults in underdeveloped regions.
"Our finding is very meaningful to dementia prevention for economically disadvantaged older adults, especially those with low energy intake. Further longitudinal studies are warranted to confirm this association."
"Dietary Patterns Associated with Cognitive Function among the Older People in Underdeveloped Regions: Finding from the NCDFaC Study"
Authors: Zhaoxue Yin, et al.