Diet to Prevent Dementia
Alzheimer’s disease (AD) is the most common cause of dementia. It affects up to 20% of individuals over 80 years of age. It is a complex disease involving chronic neuro-inflammation and neurodegeneration, characterized by beta-amyloid plaques, dysfunctional tau protein and neurofibrillary tangles in the brain. AD is a slowly progressive disease leading to cognitive decline and memory impairment which affect daily living and social functioning.
A growing body of evidence shows that lifestyle habits and nutritional patterns could delay the course of the neurodegeneration process. There is no single dietary pattern proven to prevent AD or dementia. Nevertheless, research suggests that by adopting several dietary habits, accompanied by a healthy lifestyle, the negative consequences of dementia may be delayed (1).
Diet to Prevent Dementia
Various nutrients and food items such as omega 3 fats, polyunsaturated fatty acids, vitamins, and antioxidants have been investigated for their potential protective role in dementia. Results have remained inconclusive, and research has shifted toward examination of dietary patterns. Various dietary patterns have been researched for their effects on cognitive decline. Here are the main dietary protocols that are being investigated for the prevention of Alzheimer’s disease and cognitive decline:
Caloric restriction – this involves reducing calorie intake on a daily basis. It is often used alongside other dietary approaches such as a Mediterranean diet.
Intermittent Fasting – this may involve eating during a restricted time window such as between 10am and 6pm each day. Or it may involve having a couple of days a week where just 500-800 calories are eaten. Normal eating is resumed on the other days. This may be combined with other dietary patterns involving specific foods.
Ketogenic diets – high fat ketogenic protocols that include carbohydrate restriction, often alongside time restricted eating, may hold promise for Alzheimer’s prevention in those who are genetically predisposed to the disease (1,2).
Mediterranean diet – adherence to the Mediterranean diet is associated with decreases in cardiovascular and neurological disorders, including AD, and related cognitive decline (1,3). This diet consists of fruit, vegetables, legumes, nuts, seeds and fish. It is high in polyphenol rich foods such as olives (4), berries, nuts, seeds and red wine. It is low in meat and dairy products and moderate in alcohol.
Mediterranean-DASH diet Intervention for Neurological Delay (MIND) – a hybrid of the Mediterranean and DASH diets, with modifications based on the science of nutrition and the brain. The diet recommends 10 healthy food groups: green leafy vegetables, other vegetables, nuts, berries, beans, whole grains, fish, poultry, olive oil, and wine and recommends avoiding 5 unhealthy food groups: red meats, butter and margarine, cheese, pastries and sweets, and fried/fast food. It is associated with slower rates of cognitive decline and a significant reduction in Alzheimer’s disease (3,5).
Nutrients for Brain Health – nutrients play a key role in brain development and functioning. In addition some nutrients have a particular effect on the development of AD, due to their role in neurotransmitter synthesis, modulation of epigenetic mechanisms, and as antioxidants. In addition, some non-nutrient food-derived substances have shown potential in the control of neuro-inflammation and consequently in the prevention of AD (6). Compounds such as curcumin, resveratrol, epigallocatechin-3-gallate, quercetin, luteolin, limonoids, aged garlic extract and B-complex vitamins are being investigated for their potential role in Alzheimer’s prevention (7).
Foods to Avoid – dietary interventions also include advice to eliminate or reduce certain high-risk foods including artificially sweetened drinks, sugary drinks, ultra-processed foods, trans fats, and advanced glycation end product–rich foods such as fats and proteins cooked at high temperatures,
Combining some of these dietary practices with physical and mental exercise is likely to lead to the best outcomes. For more information see blog posts on Healthy Habits to Reduce Dementia and The Microbiome and Alzheimer’s Disease.
References
1. 2020 Apr 8;12(4):1019. Influence of the Mediterranean and Ketogenic Diets on Cognitive Status and Decline: A Narrative Review. Vinciguerra F et al.
2. Diabetes Metab Syndr. Mar-Apr 2019;13(2):1187-1191. Ketogenic diet rescues cognition in ApoE4+ patient with mild Alzheimer’s disease: A case study. Morrill SJ, Gibas KJ.
3. Eur J Nutr. 2021; 60(2): 849–860. Dietary patterns are related to cognitive functioning in elderly enriched with individuals at increased risk for Alzheimer’s disease. Wesselman LMP et al.
4. Int J Mol Sci. 2019 Jun 7;20(11):2797. Mediterranean and MIND Diets Containing Olive Biophenols Reduces the Prevalence of Alzheimer’s Disease. Omar SH.
5. Contemp Clin Trials. 2021 Mar;102:106270. Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) study: Rationale, design and baseline characteristics of a randomized control trial of the MIND diet on cognitive decline. Liu X et al.
6. Clin Geriatr Med. 2018 Nov;34(4):677-697. Nutrition and Alzheimer Disease.Munoz-Fernandez SS et al.
7. J Alzheimers Dis. 2020;77(1):33-51. The Emerging Role of Nutraceuticals and Phytochemicals in the Prevention and Treatment of Alzheimer’s Disease. Calfio C et al.