Over 20 million people in the United States (about 8% of the population) have type 2 diabetes.1 Worldwide prevalence of diabetes in adults is about 6%, and Asian countries have somewhat higher rates (9% in China and Korea, and 11% in Japan).2,3 This is interesting to consider. In spite of considerably more overweight and obesity in the USA and our dangerous diet, there is considerably more diabetes in China, Korea and Japan. This is mostly because of white rice.
Type 2 diabetes arises out of insulin resistance, a state in which the body’s cells cannot respond properly to insulin – a hormone that allows for the transport of glucose into the body’s cells and storage of the energy contained in that glucose. Carrying excess fat and eating high glycemic load (GL) foods contribute to the development of insulin resistance (and of course, eating high glycemic foods contributes to weight gain).
Refined carbohydrates like white rice, devoid of fiber to slow down absorption of sugars, raise blood glucose more and faster than their intact, unprocessed counterparts. The effect of a food on blood glucose is indicated by its glycemic index (GI) – a 1-100 measure of the blood glucose response per gram of carbohydrate. Glycemic load (GL), a related indicator, takes into account both the GI and the carbohydrate content of a typical portion size.
A meta-analysis has explored the link between white rice and diabetes
An analysis of four prospective studies on white rice consumption and diabetes has been published – it included 2 studies in Asian populations and 2 in Western populations. In Asian countries, where white rice is a staple food, the average intake of white rice was 3-4 servings per day, and in Western countries the average was 1-2 servings per week. A comparison of the highest vs. lowest white rice intake groups yielded a 55% increase in diabetes risk in Asians, and a 12% increase in Westerners. Overall, the researchers found that each daily serving of white rice increased the risk of diabetes by 11%.4
This research serves to remind us: High-glycemic, nutrient-depleted, refined carbohydrates (like white rice) are more than just empty calories – they are disease-causing foods.
Westerners on average ate less than one daily serving of white rice – but what about the other high-GL foods that Americans eat daily? White pasta, white potato, and white bread are also high in GL and therefore likely to be just as dangerous. It’s no wonder that U.S. diabetes rates have tripled in the past 30 years, and are expected to double or even triple by 2050.2
(High = 20 and above; Low = 1-10)
|White potato (1 medium baked)||29|
|White rice (1 cup cooked)||26|
|White bread (1 bagel, 3.5 in. diameter)||24|
|White pasta (1 cup cooked)||21|
|Chocolate cake (1/10 box cake mix + 2T frosting)||20|
|Black rice (1 cup cooked)||14|
|Butternut squash (1 cup cooked)||8|
|Green peas (1 cup cooked)||8|
|Lentils (1 cup cooked)||8|
|Black beans (1 cup cooked)5||6|
Indeed, more and more research is demonstrating potato consumption is associated with diabetes, and this association was found to be most likely due to glycemic load (not due to preparation or added fats). Substituting 1 serving of whole grains per day with potatoes was estimated to increase diabetes risk by 30%.6 Also, in a 6-year study of 65,000 women, those with diets high in refined carbohydrates from white bread, white rice, and pasta were 2.5 times as likely to be diagnosed with type 2 diabetes compared to those who ate lower-GL foods such as intact whole grains and whole wheat bread.7
Not just diabetes – cancer too
High GL foods have dangers that reach beyond diabetes. Diets including large quantities of high GL foods increase the risk of several chronic diseases including diabetes, heart disease, and cancers.8 Let’s make it clear: white rice, white flour products, and white potatoes are foods that should not be central in our diets. Low-nutrient, high glycemic foods are not only unfavorable from the perspective of weight gain and diabetes, but could also contribute significantly to cancer by causing excessive insulin secretion. High insulin levels in the blood can promote the growth of cancer cells, in part by interacting with the receptor for insulin-like growth factor 1 (IGF-1).9 A study of Korean women found that each daily serving of white rice increased breast cancer risk by 19%.10 Similarly, a U.S. study found a link between starch consumption and breast cancer recurrence.11 Diabetics are 30% more likely to develop colorectal cancer, 20% more likely to develop breast cancer, and 82% more likely to develop pancreatic cancer than non-diabetics. This increased risk of cancer observed in diabetics is thought to be due in part to cancer-promoting effects of insulin therapy.12,13
In the past, white rice was looked upon as a healthful, low fat staple in a vegetarian diet. We have progressed in knowledge and science and it is clear that white rice can no longer be considered healthful, or even neutral – it is a disease-causing food. The damaging effects of high-GL foods have been brought to light, and we now know that the most healthful carbohydrate sources are those that minimize glycemic effects – beans, peas, intact whole grains, and starchy vegetables.
1. American Diabetes Association: Diabetes statistics [http://www.diabetes.org/diabetes-basics/diabetes-statistics/]
2. World Health Organization. Diabetes Fact Sheet. [http://www.who.int/mediacentre/factsheets/fs312/en/ ]
3. IDF Diabetes Atlas: Fifth Edition. International Diabetes Federation; 2011.
4. Hu EA, Pan A, Malik V, et al: White rice consumption and risk of type 2 diabetes: meta-analysis and systematic review. BMJ 2012;344:e1454.
5. Atkinson FS, Foster-Powell K, Brand-Miller JC: International tables of glycemic index and glycemic load values: 2008. Diabetes Care 2008;31:2281-2283.
6. Halton TL, Willett WC, Liu S, et al: Potato and french fry consumption and risk of type 2 diabetes in women. Am J Clin Nutr 2006;83:284-290.
7. Salmeron J, Manson JE, Stampfer MJ, et al: Dietary fiber, glycemic load, and risk of non-insulin-dependent diabetes mellitus in women. JAMA 1997;277:472-477.
8. Barclay AW, Petocz P, McMillan-Price J, et al: Glycemic index, glycemic load, and chronic disease risk--a meta-analysis of observational studies. Am J Clin Nutr 2008;87:627-637.
9. Gallagher EJ, LeRoith D: The proliferating role of insulin and insulin-like growth factors in cancer. Trends Endocrinol Metab 2010;21:610-618.
10. Yun SH, Kim K, Nam SJ, et al: The association of carbohydrate intake, glycemic load, glycemic index, and selected rice foods with breast cancer risk: a case-control study in South Korea. Asia Pac J Clin Nutr 2010;19:383-392.
11. Emond JA, Patterson RE, Pierce JP: Change in Carbohydrate Intake and Breast Cancer Prognosis. In San Antonio Breast Cancer Symposium, vol. Presentation #P3-09-01; 2011.
12. Pollak M, Russell-Jones D: Insulin analogues and cancer risk: cause for concern or cause celebre? Int J Clin Pract 2010;64:628-636.
13. Experts call for further research into the relationship between insulin therapy and cancer. 2010. EurekAlert! http://www.eurekalert.org/pub_releases/2010-03/w-ecf030210.php. Accessed October 20, 2011.