Tuesday, January 4, 2011

Research Update: The Right Rice And Surprising News About Milk

White rice, brown rice and risk of type 2 diabetes
Archives of Internal Medicine 2010 170:961-69

This study was by my former research group at Harvard headed by Dr. Frank Hu, an absolute nutrition all star.  This is a prospective cohort study on 157,463 women and 39,765 men from the Health Professional Follow up study and the Nurses’ Health Study I and II that were followed for about 20 years.   Participants with the highest intake of white rice (≥5 servings per week) had a 17% increased risk of type 2 diabetes compared to those with the lowest consumption of white rice (<1 serving per month).  In contrast, participants with the highest consumption of brown rice (≥2 servings per week) had an 11% lower risk of type 2 diabetes when compared to those with the lowest consumption (<1 serving per month).

Take Home Message:  Switching from white rice to brown rice is an easy thing we can all do to reduce our risk of type 2 diabetes.  Possible mechanisms presented by the authors were the higher glycemic index and the lower fiber content of white rice compared to brown rice.  The increased risk of 17% for white rice is a high number considering that this is just one food.  I actually like the taste of brown rice better anyway J

Milk and hip fractures
Journal of Bone and Mineral Research 2010 Accepted article (to be published shortly)

This is a meta-analysis that was undertaken by Harvard’s Department of Nutrition in collaboration with some European research groups.  A meta-analysis is a type of study where a researcher searches the literature for all of the relevant studies on a subject and combines them statistically to come up with a summary measure of association.  For women, 6 studies were combined (195,102 women and 3,574 hip fractures) and they found no protective effect whatsoever for milk and hip fracture.  In men, 3 studies were combined (75,149 men and 195 hip fractures) and again they found no significant protective effect of milk on risk of hip fracture.

Take Home Message: This may come as a huge surprise to a lot of people, but milk may not be a big player at all if your goal is to reduce risk of hip or other fractures.  This is not the first meta-analysis to find a neutral effect of milk on risk of hip fracture.  In fact, from an ecological perspective, the countries with the highest dairy intake (Northern European countries) have the highest risk of fracture while the countries with the lowest intake of dairy (African countries) have the lowest risk of fracture.

If you’ve read my book or work with me privately, you already know that I’m not a big fan of dairy products to start.  #1) We are the only species to drink another species milk.  #2) Most adults are unable to digest the protein in milk. #3) Dairy was designed for the cow and they have 4 stomachs.   So how do you protect your bones?  Make sure you are getting enough vitamin D, get enough physical activity (both cardio and strength training) and be sure to get calcium from your diet independent of milk.  You can find it in dark green, leafy vegetables like lettuce, spinach and kale, beans, legumes, salmon, oranges and almonds.


Anonymous said...

I wonder about the increasing incidence of diabetes in Japan, Tom. I believe they eat white rice and it is not a factor in this. The westernization of their culture certainly is, however. I do agree with having brown rice instead none the less.

As for dairy. Not a big fan of it myself. I'm in the only for baby cows group. There are plenty of good sources of calcium besides dairy. Add adequate vit D and stress bearing exercises and I would think it would be helpful for the incidence of fractures.

Dr. Thomas Halton said...

Thanks for the comment Dr. J,
It seems that from a metabolic standpoint, a large amount of physical activity tends to minimize the effects of the glycemic load on negative health outcomes. At Harvard, my research group was always discussing the fact that a high glycemic load had such a negative impact on health for Americans but not for the Asian cultures that ate so much white rice.

It turned out that the Chinese and Indian people engaged in a very large amount of physical activity, usually working on their feet in farms or factories for hours upon hours a day. Now that the economies in these countries are starting to improve, workers are becoming much more sedentary and sure enough, rates of obesity, heart disease and type 2 diabetes are sky rocketing in these countries.

It will become increasingly important for these nations to focus on lowering the glycemic load of their diets now that physical activity is becoming more Americanized (AKA non-existent!).