Does White Rice Cause Type 2 Diabetes?

Rice was first domesticated in the Yangtze River Valley in China

The following article at Yahoo News suggests it does.

http://ca.news.yahoo.com/white-rice-seen-type-2-diabetes-says-study-233837784.html

Background

Rice was first domesticated 8 or 9000 thousand years ago in China.

Among populations that eat rice as a staple food, white rice is the primary contributor to glycemic load.

Diabetes is characterized by elevated blood sugars.  Glycemic index (GI) is an indicator of how high a carbohydrate source tends to increase blood sugar.  The higher the GI, the higher the blood sugar.  The average glycemic index for white rice is 64; for brown rice it’s 55, and for whole wheat it’s 41. 

Study Method

Boston-based researchers looked for well-designed research that focused on development of diabetes over time, while measuring white rice consumption in the study population.  They found and combined four studies involving populations in China, Japan, the U.S., and Australia.  Out of a total of 352,328 participants, 13,284 developed type 2 diabetes over the course of four to 22 years.

Findings

Comparing the highest white rice consumers (over 450 g/day) with the lowest consumers (under 300 g/day, roughly), the risk of diabetes was 55% higher in the heavy consumers.  This applied only to the Asian populations.  The more rice servings per day, the higher the risk.

The Asian populations ate an average of 3 or 4 servings of white rice daily.  The Western populations ate quite a bit less: 1 or 2 servings weekly.

So What?

Western populations don’t eat nearly as much rice as Asians.  If they did, would they show a similar dose-response to white rice consumption and development of diabetes?  Nobody knows for sure, but I suspect so. 

Glycemic load has already been linked to development of type 2 diabetes in Western populations, at least in women.  To the extent that heavy white rice consumption is a glycemic load, reducing intake may lower risk of diabetes.

Chinese and Japanese at risk for type 2 diabetes should consider cutting back on white rice if they’re at the very high end of consumption.  That’s probably good advice for Westerner’s, too. 

Steve Parker, M.D.

Reference: Hu, Emily, et al.  White rice consumption and risk of type 2 diabetes: Meta-analysis and systemic review.  British Medical Journal, 2012:e1454.   doi: 10.1136/bmj.e1454