A Global Perspective on White Rice Consumption and Risk of Type 2

Diabetes Care Volume 43, November 2020 2625 COMMENTARY

A Global Perspective on White Rob M. van Dam Rice Consumption and Risk of Type 2 Diabetes Diabetes Care 2020;43:2625–2627 | https://doi.org/10.2337/dci20-0042

Preventive policies to improve diet and prospective cohort studies in Asian coun- The PURE study is a large prospective physical activity are urgently needed to tries, higher white rice consumption was cohort study using standardized me- stem the rising global burden of type 2 associated with a higher risk of type 2 thodology that facilitates comparing diabetes (1). In randomized trials, both diabetes. Therefore, it is crucial to de- results for different world regions. How- high-carbohydrate diets (low in satu- terminewhetherwhitericeconsump- ever, the inclusion of many different rated fat and high in fiber), combined tion contributes to the development of countries also represents challenges with physical activity and caloric restric- type 2 diabetes, particularly in populations for analyzing and interpreting the tion, and moderate-fat Mediterranean with high intake levels. data. First, the differences in rice intakes diets reduced diabetes risk (2). These Bhavadharini et al. (12) evaluated the for the various regions were so large that findings suggest that diets with variable association between white rice consump- there was limited overlap in intake dis- carbohydrate intakes are compatible tion and diabetes risk in ;130,000 par- tributions. As a result, participants in low with diabetes-prevention lifestyles but ticipants aged 35 to 70 years in the and high rice intake categories differed do not identify the optimal amount and Prospective Urban Rural Epidemiology greatly in their risk factor profiles be- type of dietary carbohydrates. Further- (PURE) cohort study. This study’sunique cause they were mostly from different more, the impact of high carbohydrate feature is that it represents 21 countries in world regions. Also, the used categori- intakes in other parts of the world be- Asia, North and South America, Europe, zation of rice consumption did not allow yond the range studied in Western pop- and Africa. White rice consumption was the evaluation of contrasts in rice intake ulations remains unclear. classified according to the number of that were most relevant for the distri- Rice provides ;20% of the world’s standard bowls (150 g) of rice consumed, bution in different regions. Surprisingly, calorie intake (3). Of the 10 countries ranging from less than one bowl per day the highest rice intake category (median with the largest number of diabetes to three or more bowls per day. Partic- 900 g/day) was not associated with a cases, 6 countries in Asia and South ipants with high rice consumption had a higher diabetes risk than the second- America have rice as the main staple very high intake of carbohydrate (71% of highest category (395 g/day), which is food (4). Rice is predominantly con- total energy) and low intakes of fat (15%), not consistent with a dose-response re- sumed as white rice, a refined grain protein (12%), and fiber (11 g/day). lationship. A downside of the large num- resulting from a milling process that During a mean of 9.5 years, ;6,000 in- ber of countries included in the PURE removes the bran and germ and leaves cident cases of diabetes occurred. High study is that most countries’ participant the starchy endosperm. As a result, white white rice consumption was associated numbers were too small for independent rice is low in fiber, polyphenols, and with a 20% higher diabetes risk (95% analyses. Confounding factors may differ micronutrients such as magnesium CI 3% to 41%) compared with low rice substantially by country, and country- that may benefit glucose metabolism consumption. However, risk estimates specific analyses would have allowed (5–7). White rice also has a high glycemic differed by region, with a 65% higher risk for a more rigorous exploration and ad- index (GI) and glycemic load (GL), reflect- for high versus low rice consumption in justment for confounders. In general, a ing high postprandial blood glucose lev- South Asia and no substantial associa- more detailed evaluation of potential els (5). In several (8–10) but not all (9–11) tion in China. confounders such as intakes of alcohol,

Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Republic of Singapore Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA Corresponding author: Rob M. van Dam, [email protected] © 2020 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at https://www.diabetesjournals.org/content/license. See accompanying article, p. 2643. 2626 Commentary Diabetes Care Volume 43, November 2020

coffee, dairy, and red meat would have prospective studies (20). The arsenic 4. International Diabetes Federation. IDF Diabetes been desirable (6). content of rice varies by region depend- Atlas, 9th edition, 2019. Accessed 31 August 2020. In line with the PURE study results for ing on soil and water contamination (19), Available from https://www.diabetesatlas.org fi 5. Wu W, Qiu J, Wang A, Li Z. Impact of whole South Asia, higher re ned grain con- which could contribute to variation in cereals and processing on type 2 diabetes mellitus: sumption was strongly associated with rice’s health effects. a review. Crit Rev Food Sci Nutr 2020;60:1447–1474 higher diabetes risk in a South Indian An important issue is what foods are 6. Neuenschwander M, Ballon A, Weber KS, cohort study (13). The lack of association optimal alternatives for white rice to et al. Role of diet in type 2 diabetes incidence: between rice consumption and diabetes reduce diabetes incidence. Brown rice umbrella review of meta-analyses of prospective fi fi observational studies. BMJ 2019;366:l2368 risk in China agrees with previous nd- is higher in ber and micronutrients 7. Sun Q, Spiegelman D, van Dam RM, et al. ings for Singapore Chinese and Japanese than white rice (5), but it can be high-GI White rice, brown rice, and risk of type 2 diabetes men (9,11) but not for women in Shang- depending on the rice variety (high or low in US men and women. Arch Intern Med 2010; hai and Japan (8,9). Findings from pop- amylose) and preparation (21). One po- 170:961–969 ulations with lower rice consumption tential concern is that arsenic levels are 8. Villegas R, Liu S, Gao YT, et al. Prospective study of dietary carbohydrates, glycemic index, levels have also been mixed (7,10). higher in brown rice than white rice if glycemic load, and incidence of type 2 diabetes Thus, the available evidence raises the grown in arsenic-rich areas (19). In U.S. mellitus in middle-aged Chinese women. Arch question of what may explain the vari- cohorts, replacement of white rice with Intern Med 2007;167:2310–2316 ation in associations between white rice brown rice was associated with lower 9. Nanri A, Mizoue T, Noda M, et al.; Japan Public consumption and diabetes risk across diabetes risk, although the risk reduction Health Center-based Prospective Study Group. Rice intake and type 2 diabetes in Japanese men different populations. was greater for replacement with mixed and women: the Japan Public Health Center-based In lower-income rice-consuming pop- whole grains (7). In a subgroup with the Prospective Study. Am J Clin Nutr 2010;92:1468–1477 ulations in Asia, individuals commonly metabolic syndrome, parboiled brown 10. Golozar A, Khalili D, Etemadi A, et al. White rice intake and incidence of type-2 diabetes: derive most of their dietary energy from rice consumption reduced HbA1c levels white rice (14). In this context, high rice compared with white rice in a crossover analysis of two prospective cohort studies from Iran. BMC Public Health 2017;17:133 consumption will be associated with low trial in India (22). Low-GI varieties of rice 11. SeahJYH,KohWP,YuanJM,vanDamRM.Rice consumption of many other food groups, also warrant consideration, but results intake and risk of type 2 diabetes: the Singapore resulting in an unbalanced diet lacking from trials in people without diabetes Chinese Health Study. Eur J Nutr 2019;58:3349–3360 in fiber, micronutrients, polyunsaturated suggest that reducing carbohydrate in- 12. Bhavadharini B, Mohan V, Dehghan M, et al. White rice intake and incident diabetes: a study fatty acids, and healthy sources of pro- take through replacement with unsatu- of 132,373 participants in 21 countries. Diabetes tein(14).Sucha dietary patternislikelyto ratedfatismore likelytoimproveglucose Care 2020;43:2643–2650 be associated with a higher risk of type 2 metabolism than GI reduction (23,24). 13. Anjana RM, Sudha V, Nair DH, et al. Diabetes diabetes (6), but this will not be solely The PURE study highlights that more inAsianIndiansdhowmuchispreventable?Ten- due to white rice intake. Economic de- research on the health impact of high- year follow-up of the Chennai Urban Rural Epi- demiology Study (CURES-142). Diabetes Res Clin velopment in China has been associated carbohydrate foods in different world Pract 2015;109:253–261 with increasing dietary diversity, moving regions is warranted (12). Such research 14. Sowmya N, Lakshmipriya N, Arumugam K, from the dominance of staple foods to should include prospective cohort stud- et al. Comparison of dietary profile of a rural increasing consumption of cooking oils, ies that evaluate specific food substitu- south Indian population with the current dietary animal products, and vegetables (15). In tions (7,11) and longer-term randomized recommendations for prevention of non-com- municable diseases (CURES 147). Indian J Med recent decades, these dietary changes trials of various white rice alternatives. Res 2016;144:112–119 may have changed the dietary pattern Currently, reducing white rice consump- 15. Li Y, Wang DD, Ley SH, et al. Time trends of associated with high rice consumption tion to achieve a more balanced dietary dietary and lifestyle factors and their potential and its association with diabetes risk. pattern with a variety of whole grains, impact on diabetes burden in China. Diabetes White rice typically has a high GI and fruits, vegetables, legumes, nuts, and Care 2017;40:1685–1694 16. Livesey G, Taylor R, Livesey HF, et al. Dietary GL, resulting in high postprandial blood nontropical vegetable oils can be recom- glycemic index and load and the risk of type 2 glucose and insulin levels that have been mended to reduce the risk of type 2 di- diabetes: assessment of causal relations. Nu- postulated to reduce insulin sensitivity abetes and cardiovascular diseases (6,25). trients 2019;11:1436 and b-cell function (16). In several pro- 17. Livesey G, Taylor R, Livesey HF, et al. Dietary spective cohort studies, dietary GI and GL glycemic index and load and the risk of type 2 diabetes: a systematic review and updated meta- Duality of Interest. No potential conflicts of were directly associated with type 2 di- analyses of prospective cohort studies. Nutrients interest relevant to this article were reported. abetes risk (17). Based on this mecha- 2019;11:1280 nism, the impact of white rice is expected 18. Gao H, Salim A, Lee J, Tai ES, van Dam RM. 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