White rice and resistant starchOne of last week’s big nutrition news items was about a method to reduce the calories in white rice. Researchers from Sri Lanka found that when you add a small amount of fat to white rice during the cooking process, and then refrigerate the cooked rice for at least 12 hours, the result is a higher content of resistant starch.

Resistant starch is starch that is poorly digested in the small intestine, and there is lots to like about it. Since it isn’t well digested and absorbed, this type of starch provides fewer calories than other carbohydrates. It also stimulates growth of good bacteria in the colon and production of short chain fatty acids. These fats may lower the pH of the intestines which inhibits growth of harmful bacteria. Consumption of resistant starch has been associated with improved intestinal health and better insulin sensitivity (1-5).

The potential benefits of boosting the resistant starch content of rice are likely to be greatest for people in Asia who have chronic diseases like diabetes and metabolic syndrome and whose diets include large amounts of white rice. Asians are at high risk for diabetes compared to people of European ancestry. There is evidence that Asians have a much greater blood glucose response to rice compared to people of other ethnicities (6-10). Among Asian populations, overreliance on white rice and other refined starches like noodles is linked to higher risk for chronic disease (11-14).

It’s certainly possible that shifting the starch content of white rice toward resistant starch could have benefits in these populations. And the fact that cooks can do this easily at home is a plus. Replacing some refined starch with good fats isn’t a bad idea either. (So far, these researchers have used only coconut oil, but they plan to test healthier fats.)

But what does it mean for the average vegan? I would say probably not much. Hopefully, you are not eating all that much white rice. Although I might have it occasionally at a restaurant, I doubt that I eat white rice more than three or four times a year. Instead, like most vegans, my diet is built around foods that are rich in resistant starches and in fiber. Beans are especially good sources of resistant starch as are bananas, uncooked oats, and barley.

So while there may be public health benefits of these findings for some population groups, I wouldn’t change any of my cooking practices based on them. If you eat a diet based mostly on whole plant foods, you don’t need to worry about whether the occasional cup of white rice in your meals has a lot or a little bit of resistant starch.

 

References:
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  2. Grabitske HA & Slavin JL. Gastrointestinal effects of low-digestible carbohydrates. Crit Rev Food Sci Nutr 2009; 49:327-360.
  3. Maki KC, Phillips AK. Dietary substitutions for refined carbohydrate that show promise for reducing risk of type 2 diabetes in men and women. J Nutr 2015;145:159S-163S
  4. Yamada Y, Hosoya S, Nishimura S, Tanaka T, Kajimoto Y, Nishimura A, Kajimoto O. Effect of bread containing resistant starch on postprandial blood glucose levels in humans. Biosci Biotechnol Biochem.2005;69:559-566.
  1. Noakes M, Clifton PM, Nestel PJ, Le Leu R, McIntosh G. Effect of high-amylose starch and oat bran on metabolic variables and bowel function in subjects with hypertriglyceridemia. Am J Clin Nutr. 1996; 64:944-61.
  1. Chan JC, Malik V, Jia W,et al. Diabetes in Asia: epidemiology, risk factors, and pathophysiology. JAMA 2009; 301:2129–2140.
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  1. Song S, Young Paik H, Song WO, Song Y. Metabolic syndrome risk factors are associated with white rice intake in Korean adolescent girls and boys. Br J Nutr 2015;113:479-87.
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