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Monday, June 14, 2010

Nonsensical Study About White Rice

So Why Is Diabetes Rare in China?


A recent study has warned us that people who eat white rice instead of brown rice are more likely to get diabetes! But it leaves out a crucial piece of information: people in Asian countries whose diet is based heavily on white rice are practically immune to type 2 diabetes. The take-home message from this study isn’t that white rice is harmful, or that it would make much difference if you ate brown rice instead. It’s that we should be wary of researchers who fail to read the basic literature on nutrition before they design their research.

Brown rice is the whole-grain version of rice. To make brown rice, you remove only the husk of the rice seed. To make white rice, you also grind off the bran layer and the germ, which is the embryo of the rice seed. In most of the areas where rice is the staple of the diet, people prefer white rice, for two very practical reasons: brown rice goes rancid very easily, and it takes a lot longer to cook.

Polishing off the bran and germ of the rice seed removes the oils that can cause spoilage. Unfortunately, it also removes most of the vitamin B1 (thiamine) from the rice. Originally, white rice was an expensive food, reserved largely for rich people who could afford a varied diet, so the lack of vitamin B1 in their rice wasn’t a big deal. Unfortunately, when the invention of steam-powered rice mills meant that lots of poor people were subsisting heavily on white rice, a debilitating and potentially deadly deficiency disease called beriberi became endemic in Asia. After chemists identified thiamine and figured out how to make it cheaply to “enrich” white rice, beriberi ceased to be a common problem. Even so, brown rice is better for you because it’s a source of fiber.

Back in the 1930s and 1940s, a German-born American physician named Walter Kempner recognized the health benefits of a plant-based diet centered on rice. Kempner recognized that heart disease and diabetes were rare in Asia, where people ate a rice-based diet that was low in fat and cholesterol. He started recommending a diet based on rice, fruit, fruit juices, and sugar for patients with severe high blood pressure and kidney disease. His spectacular results with these patients encouraged him to recommend this rice-based diet for people with heart disease and diabetes. Those patients also got dramatic benefits, even though most of these patients were eating white rice. So where did the authors of the study published in Archives of Internal Medicine get the idea that white rice might cause diabetes?

It’s been obvious since the 1870s that type 2 diabetes is linked to obesity. We’ve known since the 1930s that the poor glucose tolerance that underlies it is linked to a high-fat diet and can be reversed by a switch to a starchy diet. The China-Cornell-Oxford Project, also known as the China Study, demonstrated that people who are eating a low-fat diet based heavily on white rice and vegetables stay slim and are virtually immune to diabetes. So why did the researchers just try to implicate white rice as a cause of diabetes? Could it be that they have never bothered to read the historical literature on the subject?

If you are eating the standard American diet, you are at high risk for obesity, type 2 diabetes, various kinds of cancer, and a wide assortment of other degenerative diseases. That’s because those diseases have been linked to a high intake of animal protein, fat, and cholesterol. You can dramatically reduce your risk of those diseases by switching to a low-fat (<10% of calories), high-fiber diet based on plant foods. As long as you get enough thiamine and enough fiber in your diet, it doesn’t matter much if the rice you eat is white.