A study published within the journal Alzheimer’s Research & Therapy describes that the Mediterranean and MIND diets could effectively preserve episodic and visuospatial working memory in midlife.
Study: Food plan patterns and cognitive performance in a UK Female Twin Registry (TwinsUK). Image Credit: DiViArt / Shutterstock
Background
Age-related cognitive decline is a public health concern as it will probably affect morbidity and mortality. Although most people experience cognitive decline in midlife, the speed of cognitive decline can significantly vary between individuals depending on their cardiovascular health and lifestyle behaviors. A faster-than-usual rate of cognitive decline with age could be a risk factor for Alzheimer’s disease.
Nutrient-rich dietary patterns, akin to the Mediterranean (MED) and the Mediterranean-dietary approaches to stop hypertension intervention for neurodegenerative delay (MIND) diets, are known to have neuroprotective and cognition-enhancing abilities. On this context, evidence indicates that the MED weight loss program can improve cognitive functions by positively influencing the gut microbiota.
On this study, scientists have investigated the impact of MED and MIND diets on cognitive function and 10-year change in cognitive performance in cognitively healthy female twins.
Study design
The study analyzed data obtained from the UK Adult Twin Registry that enrolled healthy female twins between 1992 and 2004. A complete of 509 female twins who had complete baseline data on weight loss program and cognitive performance between 1998 and 2000 were included within the evaluation. Of those twins, 34% were monozygotic (genetically an identical) and 66% were dizygotic (50% an identical genes).
The baseline dietary intake was assessed using a food frequency questionnaire. The dietary intake data was used to calculate weight loss program scores for the MED and MIND dietary patterns. The next dietary rating is indicative of upper adherence to the respective diets.
The participants’ cognitive performance was assessed at baseline and after ten years (2008 – 2010). Six forms of cognitive functions were tested, including response speed, spatial working memory, episodic memory, visual episodic memory, decision time, and visuospatial working memory.
Fecal samples were collected from the participants on the 10-year follow-up to research gut microbiota.
Change in adjusted mean (SE). Age-related cognition and spatial span length over 10 years in MZ twins discordant for MIND and MED weight loss program rating
Necessary observations
The assessment of the impact of dietary patterns on baseline cognitive performance revealed no significant association between MED weight loss program scores and cognitive test scores. For the MIND weight loss program, each 1-point increase in weight loss program rating was found to be related to faster response time and higher visual episodic memory after adjusting for demographic, health, and lifestyle confounding aspects.
The assessment of the impact of dietary patterns on cognitive performance at a 10-year follow-up revealed that increasing adherence to the MED or MIND weight loss program is related to improved episodic memory.
The assessment of the impact of dietary patterns on 10-year change in cognitive performance within the discordant monozygotic twin pairs revealed that the monozygotic twin with a high weight loss program rating has less decline in global cognition basically. Nevertheless, this difference was not statistically significant.
Inside each monozygotic pair, the dual with high MED or MIND weight loss program scores observed greater preservation of visuospatial working memory. This remark was significant for the MED weight loss program. No significant impact of MED or MIND weight loss program on 10-year change in other cognitive performances was observed in discordant monozygotic twins.
Regarding the connection between dietary patterns and gut microbiota, the findings revealed that prime adherence to the MIND weight loss program at baseline is related to the next abundance of Ruminococcaceae UCG-010 (short-chain fatty acid-producing bacteria) and a lower abundance of Dorea at 10-year follow-up. This association became non-significant after adjusting for dietary fiber intake.
Further evaluation revealed that the next abundance of Ruminococcaceae UCG-010 is related to a lower decline in global cognition and improved spatial working memory on the 10-year follow-up.
Study significance
The study finds that each MED and MIND diets could effectively preserve episodic and visuospatial working memory in midlife. These neuroprotective effects might be attributed to high dietary fiber content and increased abundance of short-chain fatty acid-producing bacteria within the gut.
As mentioned by the scientists, the possible influence of unidentified genetic aspects on the study outcomes in your entire study population can’t be ruled out, as the identical pattern of cognitive improvement has not been present in monozygotic co-twins.
Future studies should include longer follow-ups with repeated cognitive assessments to know the impact of weight loss program on cognitive performance in older age.