Plant-Based Dietary Patterns, Plant Foods, and Age-Related Cognitive Decline

Abstract

The aging population is expanding, as is the prevalence of age-related cognitive decline (ARCD). Of the several risk factors that predict the onset and progression of ARCD, 2 important modifiable risk factors are diet and physical activity. Dietary patterns that emphasize plant foods can exert neuroprotective effects. In this comprehensive review, we examine studies in humans of plant-based dietary patterns and polyphenol-rich plant foods and their role in either preventing ARCD and/or improving cognitive function. As yet, there is no direct evidence to support the benefits of a vegetarian diet in preventing cognitive decline. However, there is emerging evidence for brain-health–promoting effects of several plant foods rich in polyphenols, anti-inflammatory dietary patterns, and plant-based dietary patterns such as the Mediterranean diet that include a variety of fruits, vegetables, legumes, nuts, and whole grains. The bioactive compounds present in these dietary patterns include antioxidant vitamins, polyphenols, other phytochemicals, and unsaturated fatty acids. In animal models these nutrients and non-nutrients have been shown to enhance neurogenesis, synaptic plasticity, and neuronal survival by reducing oxidative stress and neuroinflammation. In this review, we summarize the mounting evidence in favor of plant-centered dietary patterns, inclusive of polyphenol-rich foods for cognitive well-being. Randomized clinical trials support the role of plant foods (citrus fruits, grapes, berries, cocoa, nuts, green tea, and coffee) in improving specific domains of cognition, most notably frontal executive function. We also identify knowledge gaps and recommend future studies to identify whether plant-exclusive diets have an added cognitive advantage compared with plant-centered diets with fish and/or small amounts of animal foods.

Nutritional Status and the Influence of the Vegan Diet on the Gut Microbiota and Human Health

“…Such compounds are polyphenols found in grapes, berries, and nuts, indole-3-carbinol in cruciferous vegetables such as sprouts, cabbage, and cauliflower, isoflavones found in legumes, including clover, soy, and lupine, and lycopene in tomatoes. In general, these substances, which are referred as food ingredients, have no additive nutritional value, but they can affect various metabolic pathways of the body, providing multiple health benefits [36][37][38][39]. However, if a vegan diet is not appropriately planned, reduction of caloric intake and nutritional deficiency of fatty acids, proteins, vitamins, and minerals may appear [1].…”

Vegetarian or Vegan Diet: Stimulating or at Risk to Mental Health?

“…Some plant foods (citrus fruit, grapes, berries, cocoa, nuts, green tea and coffee) improve specific cognitive domains, most notably frontal executive functions [63].…”

Role of Lifestyle in Neuroplasticity and Neurogenesis in an Aging Brain

“…The intrinsic factors that are least likely to be modified in the process of aging are neuroinflammation, oxidative stress, and brain injury and other factors such as lifestyle that can be modified for slowing the aging process is a low intake of fat and sugar diets and alcohol and avoid opioid addictions [ 2 ]. One of the diet modifications can be done by adding polyphenols (e.g., phenolic acids, stilbenes, lignans, flavonols, and anthocyanins) which consists of 800 compounds with an antioxidant property that can be found in fruits, vegetables, tea, wine, juice, plants, and some herbs [ 3 ]. Even though polyphenols are not considered essential nutrients, these compounds can decrease the risk of age-related cognitive problems.…”

“…There is going to be an increase in the aging population, which will lead to a concomitant growth in age-related cognitive decline (ARCD). Approximately 8.5% of the world's population is aged >65 years (~617 million) and is expected to be 16.7 % by 2050 (~1.6 billion) leading to the personal, social, and economic burden of care for an individual with age-related problems which can delay healthy lifestyle measures [ 2 , 3 ].…”