Sunday, May 9, 2010

You are what you eat

The race to develop a drug to treat Alzheimer’s disease is a top priority for many pharmaceutical companies. With the aging population, the size of the market is ever increasing, and some people estimate that the winner of the race will pocket several billion dollars in the first year of a drug being on the market, in the US alone. However, it would be far easier if we could simply find a way to decrease our risk of getting Alzheimer’s disease in the first place. One recent study suggests that it’s as easy as eating healthy.

We’ve known for a long time that what you put in your plate is the single most important modifiable environmental factor for your risk of getting a variety of diseases, ranging from obvious ones like scurvy (drink your OJ!) to less obvious ones like prostate cancer (stay away from red meat!). Given these relationships, a team of researchers decided to study what combination of foods may relate to a risk of getting Alzheimer’s disease. They asked over 2000 elderly subjects to describe their eating habits in great detail, then followed them for 4 years.

After the 4 years had passed, 253 subjects had developed Alzheimer’s disease. After careful analysis of the subjects’ diets, the researchers concluded that the following diet characteristics significantly lowered your risk of developing Alzheimer’s disease:

  • The diet is rich in omega 3 and 6 fatty acids
  • The diet is rich in vitamin E and folate
  • The diet is poor in saturated fatty acids
  • The diet is poor in vitamin B12
  • Eating salad dressing, nuts, fish, tomatoes, poultry, cruciferous vegetables, fruits, dark and green leafy vegetables is correlated to a decrease in the risk of Alzheimer’s disease
  • Eating high-fat dairy, red meat, organ meat, and butter is correlated with an increase in the risk of Alzheimer’s disease.
Subjects who adhered best to the characteristics described above saw their risk of developing Alzheimer’s disease drop by 38%. By now, I’m sure my alert Scientific Chick readers are already wondering if the researchers looked at other factors, such as age. Differences in age, education, ethnicity and sex didn’t change the relationship between diet and Alzheimer’s disease. However, other factors did lessen the importance of the diet, such as smoking, body mass index, and caloric intake. But even when controlling for all these factors, the relationship between diet and risk of developing Alzheimer’s disease remained significant.

The major strength of this study is that it looked at existing dietary patterns instead of trying to impose them, which is often unreliable. However, some of the results can be misleading. A low intake of vitamin B12 may seem to protect you against Alzheimer’s disease, but it’s because a lot of food that contains B12 (such as meat and dairy) also contain high levels of saturated fats, which increase your risk for Alzheimer’s disease. Overall, as with any scientific study, the results must be interpreted carefully. It’s a combination of foods that is important: you can drink antioxidant-rich blueberry juice all you want, but if you’re having it with a side of ground beef, you’re missing the point. In addition, there could be some factor other than diet at play that the authors did not control for.

So while we don’t have a miracle drug yet, and no single food can prevent Alzheimer’s disease, it seems like a healthy, varied and unprocessed diet is a good place to start to ensure healthy aging.

P.S. It's Jello.

Reference: Food combination and Alzheimer disease risk: A protective diet (2010) Gu Y et al. Arch Neurol [Epub ahead of print]

5 Responses to “You are what you eat”

Fawn said...

Time and again, it all seems to come back to food.

Sometimes I wonder if we are now eating TOO varied a diet. Wherever each of us came from, we all had a lot fewer choices than we have now. Eating simple, natural foods would not have been a choice, but the only option!

Also: ugliest jello mold ever! LOL

Dr. Julie said...

Fawn, if you think we eat too varied a diet, I have a great book recommendation for you: The 100-mile diet: A year of local eating. I just finished it and loved every page. And I'm very thankful I don't have to eat potatoes every single day of the winter. :) But I absolutely see your point, and yes, nothing beats local, simple, unprocessed natural foods.

Shinerpunch: Many thanks. I had a case of the perma-smiles after reading the review.

Unknown said...

Salad dressing? Really? Will any kind do? Is it for fat-soluble vitamins? In which case, what about fat free dressing? Explain.

Dr. Julie said...

@ david: Yes, the salad dressing also made me wonder. I think one of the reasons it's correlated with a positive outcome is because chances are, if you're eating salad dressing, you're eating salad (hopefully!). It might just be one of those correlations, or it could be that most salad dressings contain good-for-you (but in small quantities) olive oil.

Either way, I wouldn't recommend eating salad dressing without the salad. :)

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