Dietary patterns: a novel approach to examine the link between nutrition and cognitive function in older individuals

Abstract

Cognitive decline may lead to dementia whose most frequent cause is Alzheimer's disease (AD). Among the many potential risk factors of cognitive decline and AD, diet raises increasing interest. Most studies considered diet in the frame of a single nutrient approach with inconsistent results. A novel approach to examine the link between nutrition and cognitive function is the use of dietary patterns. The aim of the present review was to update and complete the body of knowledge about dietary patterns in relationship with various cognitive outcomes in the elderly. Two approaches can be used: a priori and a posteriori patterns. A priori patterns are defined by the adhesion to a predefined healthy diet using a score such as the Mediterranean diet (MeDi) score, the Healthy Eating Index, the Canadian Healthy Eating Index, the French National Nutrition and Health Programme (Programme National Nutrition Santé) Guideline Score (PNNS-GS), the Recommended Food Score (RFS) and Dietary Approaches to Stop Hypertension (DASH). MeDi score, RFS, PNNS-GS and DASH have been associated with lower risks of cognitive impairment, cognitive decline, and dementia or AD. Principal components analysis, reduced rank regression and clustering methods allow the identification of 'healthy' patterns associated with lower risk of cognitive decline. However, some studies did not report any associations with cognitive outcomes and results are discordant especially regarding MeDi and the risk of dementia. Several methodological challenges should be overcome to provide a higher level of evidence supporting the development of nutritional policies to prevent cognitive decline and AD.

Targeting the Prodromal Stage of Alzheimer's Disease: Bioenergetic and Mitochondrial Opportunities

“…MeDi, opposed to the Western diet, is characterized by the abundant consumption of plant foods such as vegetables, fruits, breads, potatoes, legumes, nuts, [160,161] AD = Alzheimer's disease; mTOR = mammalian target of rapamycin; Aβ = β-amyloid; Nrf2 = nuclear response factor 2 and seeds; olive oil as the source of fat; moderate amounts of dairy, fish, poultry, and eggs; low intake of red meats; and wine during normal meals [173,174,195]. The nutrients within the MeDi influence biological mechanisms affecting vascular, antioxidant, and inflammatory pathways [175,176]. MeDi was demonstrated to reduce risk of heart disease, decrease markers of oxidative stress, and lower inflammatory markers; hence, MeDi adherence might delay age-related cognitive decline [177][178][179][180].…”

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“…Healthy dietary patterns such as the Mediterranean Diet, Dietary Approaches to Stop Hypertension (DASH) Diet, and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) Diet all include grain-based foods as part of a balanced pattern (88,89). The basic components and recommended servings for each of these diets are provided in Table I.…”

“…The basic components and recommended servings for each of these diets are provided in Table I. Study findings have shown that these diets are associated with lower risks for cognitive impairment, cognitive decline, and dementia or Alzheimer's disease compared with typical "Western" diets that are high in red meat, dairy products, and sweets; are low in foods that provide key nutrients; and have minimal intakes of fruits, vegetables, fish, legumes, and whole grains (88,90). The Mediterranean, DASH, and Mind Diets, as well as other patterns that focus on dietary balance and diversity, are thought to promote general health because they include nutrients and phytonutrients in beneficial proportions.…”

“…Subsequent research has shown that the diet can improve not only blood pressure but many health outcomes, including cognition (93). Such diets emphasize inclusion of vegetables, fruits, whole grains, fat-free or low-fat dairy products, fish, poultry, beans, and healthy oils and recommend moderate consumption of foods that are high in saturated fat, red meat, and wine (79,88). There are a few differences between the two diets.…”

What do we know about the nutritional status of the very old? Insights from three cohorts of advanced age from the UK and New Zealand

“…Instead of concentrating on one single nutrient or food group when testing diet-disease hypothesis (a single nutrient/food approach), recent developments in nutritional epidemiology advocate the importance of whole diet, DP and consequent interaction of foods and nutrients (a whole diet/DP approach) on health outcomes in general and older adults population (42)(43)(44)(45) . Healthy DP defined either by a greater adherence to predefined dietary scores (e.g.…”