Dietary Guidelines Aim to Reduce Alzheimer’s Risk

New dietary guidelines http for the prevention of Alzheimer’s disease have been developed by the Physicians Committee for Responsible Medicine (PCRM).

PCRM is a nonprofit organization that advocates preventive medicine, especially good nutrition; conducts clinical research; and advocates for higher ethical standards in research, according to their Web site. The new guidelines were released last week at the International Conference on Nutrition and the Brain held in Washington, DC, sponsored jointly by PCRM and George Washington University School of Medicine.

The current generation of clinicians is in a battle over food — especially Alzheimer’s-promoting foods, such as those which contain saturated and trans fats. We potentially have the capabilities to prevent a disease that is poised to affect 100 million people worldwide by 2050. 

The guidelines are very similar to the habits that prevent heart disease in that they recommends avoiding saturated and trans fats, grounding the diet in plant-based foods, and adding sources of vitamin E and B. Combining this diet with physical exercise and avoiding excess metals, such as iron and copper in multivitamins, can maximize protection for the brain.

The PCRM recommendations eating meals such as roasted broccoli salad, spiced chickpea curry, baby bok choy, and blueberry sorbet.

Several Alzheimer’s experts asked to comment on the guidelines for Medscape Medical News all had similar opinions: that the recommendations were for a healthy diet and exercise, which was always good general advice, but that high levels of evidence that following these guidelines would definitively reduce Alzheimer’s risk are lacking.

The 7 Dietary Principles to Reduce Alzheimer’s Risk

1. Minimize saturated fats and trans fats.
2. Vegetables, legumes (beans, peas, and lentils), fruits, and whole grains should be the primary staples of the diet.
3. One ounce of nuts or seeds (one small handful) daily provides a healthful source of vitamin E.
4. A reliable source of vitamin B12, such as fortified foods or a supplement providing at least 2.4 μg per day for adults) should be part of the daily diet.
5. Choose multivitamins without iron and copper, and consume iron supplements only when directed by your physician.
6. Avoid the use of cookware, antacids, baking powder, or other products that contribute dietary aluminium.
7. Engage in aerobic exercise equivalent to 40 minutes of brisk walking 3 times per week.

The Evidence

Dr. Barnard cited several studies that supported these guidelines. For example, in the Chicago Health and Aging Project, individuals who consumed the most saturated fat (around 25 g each day) were 2 to 3 times more likely to develop Alzheimer’s disease than those who consumed only half that amount. He acknowledged that not all studies agree.

For example, a Dutch study found no protective effect of avoiding saturated fats, although the population was somewhat younger than that in the Chicago study. He suggested that high-fat foods and/or the increases in cholesterol they may cause can contribute to the production of β-amyloid plaques in the brain. High-fat foods also increase the risk for obesity and type 2 diabetes, common risk factors for Alzheimer’s disease, he added.

A large study of Kaiser Permanente patients showed that participants with total cholesterol levels above 250 mg/dL in midlife had a 50% higher risk for Alzheimer’s disease 3 decades later compared with participants with cholesterol levels below 200 mg/dL, Dr. Barnard reported. And he noted that the APOE ε4 allele, which is strongly linked to Alzheimer’s risk, produces a protein that plays a key role in cholesterol transport.

Recommendation for vegetables, legumes, fruits, and whole grains –  these foods are rich in vitamins, such as folate and vitamin B6, that play protective roles for brain health. Studies of Mediterranean-style diets and vegetable-rich diets, such as the Chicago Health and Aging Project, have shown reduced risk for cognitive problems compared with other dietary patterns.

An Oxford University study of older people with elevated homocysteine levels and memory problems, in which supplementation with B vitamins improved memory and reduced brain atrophy.

On potentially harmful metals, he noted that excessive iron and copper have been linked to cognitive problems. And while the role of aluminium in Alzheimer’s disease remains controversial, he pointed out that aluminum has been demonstrated in the brains of individuals with Alzheimer’s disease, and studies in the United Kingdom and France have found increased Alzheimer’s prevalence in areas where tap water contained higher aluminium concentrations.

He added that several studies have found a correlation between exercise and a reduced risk for Alzheimer’s.

The full guidelines document is available at the PCRM Web site.

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