Here are the basic details of the study and the outcome:
Objective To assess the association between food combination and Alzheimer disease (AD) risk. Because foods are not consumed in isolation, dietary pattern (DP) analysis of food combination, taking into account the interactions among food components, may offer methodological advantages.This study offers further confirmation that the traditional Western diet is deadly, and that eating closer to nature is better for our bodies and our brains.
Design Prospective cohort study.
Setting Northern Manhattan, New York, New York.
Patients or Other Participants Two thousand one hundred forty-eight community-based elderly subjects (aged 65 years) without dementia in New York provided dietary information and were prospectively evaluated with the same standardized neurological and neuropsychological measures approximately every 1.5 years. Using reduced rank regression, we calculated DPs based on their ability to explain variation in 7 potentially AD-related nutrients: saturated fatty acids, monounsaturated fatty acids, -3 polyunsaturated fatty acids, -6 polyunsaturated fatty acids, vitamin E, vitamin B12, and folate. The associations of reduced rank regression–derived DPs with AD risk were then examined using a Cox proportional hazards model.
Main Outcome Measure Incident AD risk.
Results Two hundred fifty-three subjects developed AD during a follow-up of 3.9 years. We identified a DP strongly associated with lower AD risk: compared with subjects in the lowest tertile of adherence to this pattern, the AD hazard ratio (95% confidence interval) for subjects in the highest DP tertile was 0.62 (0.43-0.89) after multivariable adjustment (P for trend = .01). This DP was characterized by higher intakes of salad dressing, nuts, fish, tomatoes, poultry, cruciferous vegetables, fruits, and dark and green leafy vegetables and a lower intake of high-fat dairy products, red meat, organ meat, and butter.
Conclusion Simultaneous consideration of previous knowledge regarding potentially AD-related nutrients and multiple food groups can aid in identifying food combinations that are associated with AD risk.Published online: April 12, 2010 (doi:10.1001/archneurol.2010.84)
Specifically, eating a diet high salad dressing (olive oil or sometimes safflower oil), nuts, fish, tomatoes, poultry, cruciferous vegetables (broccoli, cauliflower, Brussels sprouts, kale, cabbage, and bok choy, among others), fruits, and dark and green leafy vegetables offers protection against illness, including Alzheimer's Disease.
These are all part of the typical Mediterranean diet. This diet is rich in omega-3 & omega-6 polyunsaturated fatty acids (PUFA), vitamin E, and folate. It is also lower saturated fatty acids (SFA) and vitamin B12. The B12 finding is interesting, but this single nutrient is not an indicator for increased AD risk, as the authors point out. Rather, "source foods of vitamin B12 like meat and dairy products may also contain a high level of SFA, which is a potential AD risk factor."
On the other hand, a diet high in high-fat dairy products, red meat, organ meat, and butter increases the risk of AD significantly. This diet is much higher in saturated fats,
The authors point out in the discussion that looking at a single nutrient is unlikely to generate meaningful results - with which I am in total agreement. Far too many studies try to isolate a single nutrient and then proclaim that it does nothing to increase health or decrease disease. But that is not how we eat - we eat foods that contain a variety of nutrients, which more than likely work together to create disease or prevent disease.
For example, the healthiest diet in this group included omega-3 fats (which are known to reduce the risk of heart disease and stroke while helping to reduce symptoms of hypertension, depression, attention deficit hyperactivity disorder (ADHD), joint pain and other rheumatoid problems) and cruciferous vegetables (which are known to contain anti-cancer chemicals), as well as nuts (I recommend walnuts, almonds and seeds such as pumpkin seeds and sunflower seeds), fish (salmon is best, but other fish are low in SFAs), and fruit (low sugar fruits such as apples, dark berries, and melons are best) - all of which contain healthy nutrients.
No one of these foods by itself is likely to offer overwhelming health benefits, but the combination of foods is a powerful diet-based way to increase health and longevity.
The final paragraph of the discussion sums up this study quite well:
In conclusion, we identified a DP that was strongly protective against the development of AD. The results of the current study indicate that higher consumption of certain foods (salad dressing, nuts, fish, tomatoes, poultry, cruciferous vegetables, fruits, dark and green leafy vegetables) and lower of others (high-fat dairy, red meat, organ meat, and butter) may be associated with a decreased risk of developing AD via a more favorable profile of nutrients (ie, lower ingestion of SFA and higher ingestion of PUFA, vitamin E, and folate). Our findings provide support for further exploration of food combination–based dietary behavior for the prevention of this important public health problem.Reference:
Food Combination and Alzheimer Disease Risk
A Protective Diet
Arch Neurol. 2010;67(6):(doi:10.1001/archneurol.2010.84).