Dietary and Lifestyle Management Strategies
Analysis of some dietary patterns indicates that dietary nutrient composition may affect the risk of developing Alzheimer’s disease (Gu 2011)
The Mediterranean diet has been shown to reduce the risk of Alzheimer’s and other dementias in a host of studies. A recent review found a reduced risk of Alzheimer’s among those whose dietary pattern included a higher intake of fruits, vegetables, fish, nuts, and legumes, as well as a lower intake of meats, high fat dairy, and sweets (Gu 2011). Another recent review of the literature noted a reduced risk of neurodegenerative diseases such as Alzheimer’s, Parkinson’s, and mild cognitive impairment, when patients were on a Mediterranean diet (Demarin 2011).
Yet another review found that the Mediterranean diet reduced both the risk of Alzheimer’s disease and the rate of progression from pre-dementia syndromes to overt dementia. The researchers pointed out that the Mediterranean diet largely comprises individual foods (e.g., fish, vegetable oils, non-starchy vegetables, low glycemic index fruits, and red wine), independently proposed as potential protective factors against dementia and pre-dementia (Solfrizzi 2011).
In one study, participants who most closely adhered to the Mediterranean diet, showed 28% lower risk of developing cognitive impairment over a 4.5-year period than those who were less adherent. Also, highly adherent participants with some cognitive impairment at the start of the study experienced 48% lower risk of developing Alzheimer’s disease at follow-up (an average of 4.3 years later) (Scarmeas 2009).
The Mediterranean diet also appears to affect the mortality rate in Alzheimer’s. For example, Alzheimer’s patients whose adherence to the Mediterranean diet was greatest during a study period of 4.4 years were 76% less likely to die than those whose adherence was least. Alzheimer’s patients who adhered to the Mediterranean diet to a moderate degree lived an average 1.3 years longer than those who adhered to the diet to the least degree. Patients who followed the diet very strictly lived, on average, 3.9 years longer (Scarmeas 2007).
The ketogenic diet, which involves a strict regimen of very high fat, moderate protein, and low carbohydrates, prompts the body to switch from its normal metabolic process of burning glucose to burning ketones. Ketones are substances produced when the body breaks down fat instead of glucose for energy. Initial research is being carried out to investigate the impact of the ketogenic diet on Alzheimer’s development and progression (Jóźwiak 2011). In a transgenic mouse model, 43 days on a ketogenic diet resulted in ketone production and decreased amyloid beta levels (Van der Auwera 2005).
The ketogenic diet can cause adverse side effects (e.g., increased cholesterol levels, kidney stones, and gastroesophageal reflux) (Jóźwiak 2011).
Low-Calorie Diet (Calorie restriction)
Researchers reported that a low-calorie diet reduces the risk of mild cognitive impairment, which is the stage of memory loss between normal aging and overt dementia. Healthy study subjects between ages 70 and 89 were divided into three groups based on their normal daily caloric intake: 600-1526; 1526-2143; and 2143-6000 calories per day. Those in the highest calorie group were almost twice as likely to develop mild cognitive impairment. This association was found to be dose-dependent; the risk increased gradually with the increase in calories (Geda 2012; Pasinetti 2007).
Regular exercise is associated with increases in brain-derived neurotrophic factor (BDNF), hippocampal neurogenesis, synaptic plasticity, brain volume, dendritic spines, and vascular function, as well as a reduction in cell death (Cotman 2007; van Praag 2009). Research focusing on Alzheimer’s patients found that those who exercised had reduced brain atrophy compared with those who did not (Burns 2008). As little as three minutes of very intense exercise has been shown to sharply raise BDNF levels, as well as produce a 20% improvement in memory (Winter 2007).
The benefits of exercise may be enhanced by consumption of omega-3 fatty acids and plant polyphenols (van Praag 2009). Exercise and diets rich in omega-3 fatty acids have been shown to help normalize BDNF levels (Gomez-Pinilla 2008; Wu 2004a).