Intake of whole grain foods and risk of type 2 diabetes: results from three prospective cohort studies

Dear Editor,

Yang Hu et al reported that higher consumption of total whole grains contributes to a lower risk of type 2 diabetes and encourage the high consumption of whole-grain food as a preventive strategy to type 2 diabetes. [1] I would like to discuss the implication of climate change for these findings, and its implication on human health.

Extreme weather events are increasing and they impact agricultural production and food safety, which ultimately has an impact on nutrition and health condition. Evidence shows that droughts and extreme heat significantly reduced global cereal production. [2] The Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (AR5) finds that the production of major crops (wheat, rice, and maize) is negatively affected by climate change and contributes to the rapid food and cereal price increase. [3] Asia-Pacific regions, considered as major crop-producing countries, are more sensitive and vulnerable to extreme weather. [4] It is estimated that a 15% decline in average calorie availability and a 24% decline in cereal consumption in Asia in 2050 will occur with climate change compared to the scenario without climate change. [5] Declining agricultural food production also has impacts on the food choice and health conditions of the vulnerable population in low-middle income countries with weak health infrastructure. [6] With the traditional food shortage and increased food and cereal price, the population with low-middle socioeconomic status tend to reduce the food and cereal consumption and increase consumption of unhealthy processed food. [5.7.8]

The dietary pattern change, which increases meat and unhealthy processed food consumption and decreases cereal consumption will lead to more malnourished children in Asia and the Pacific regions. [5] Diets with high consumption of meat and animal fat increase the morbidity and mortality of diet-related diseases, including obesity, type 2 diabetes, and cardiovascular diseases. [8]

Climate change has impacts on dietary patterns, while on the contrary, dietary patterns also have climate impacts. Evidence shows that the plant-based foods, which contribute to fewer greenhouse gases emission, are more climate-friendly compared to meat. [9] Studies support that healthy dietary patterns with a high proportion of plant-based foods and low proportion in animal-based foods have positive impacts on environmental sustainability. [10]

While Yang Hu et al have outlined that the benefits of whole-grain food consumption on type 2 diabetes prevention, there are wider benefits of plant-based food consumption on the human health and sustainable development of the environment and agricultural system. [1] Changing the dietary pattern towards a healthy and sustainable model is encouraged to promote public health and mitigate climate change.

References
1. Hu Y, Ding M, Sampson L, Willett WC, Manson JE, Wang M, Rosner B, Hu FB, Sun Q. Intake of whole grain foods and risk of type 2 diabetes: results from three prospective cohort studies. BMJ. 2020 Jul 8;370.
2. Lesk C, Rowhani P, Ramankutty N. Influence of extreme weather disasters on global crop production. Nature. 2016 Jan;529(7584):84-7.
3. J.R., L. Xie, A.J. Challinor, K. Cochrane, S.M. Howden, M.M. Iqbal, D.B. Lobell, and M.I. Travasso, 2014: Food security and food production systems. In: Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Field, C.B., V.R. Barros, D.J. Dokken, K.J. Mach, M.D. Mastrandrea, T.E. Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. Genova, B. Girma, E.S. Kissel, A.N. Levy, S. MacCracken, P.R. Mastrandrea, and L.L.White (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 485-533.
4. Vogel E, Donat MG, Alexander LV, Meinshausen M, Ray DK, Karoly D, Meinshausen N, Frieler K. The effects of climate extremes on global agricultural yields. Environmental Research Letters. 2019 May 3;14(5):054010.
5. International Food Policy Research Institute, Climate Change: Impact on Agriculture and Costs of Adaptation, 2009
6. Shubair MM, Haider M, Bassa M. Climate change and type 2 diabetes. J Endocrinol Diabetes Mellit. 2013 Nov 30;1:22-6.
7. Green R, Cornelsen L, Dangour AD, Turner R, Shankar B, Mazzocchi M, Smith RD. The effect of rising food prices on food consumption: systematic review with meta-regression. Bmj. 2013 Jun 17;346.
8. Dain K, Hadley L. Diabetes and climate change—Two interconnected global challenges. Diabetes research and clinical practice. 2012 Aug 1;97(2):337-9.
9. Carlsson-Kanyama A, González AD. Potential contributions of food consumption patterns to climate change. The American journal of clinical nutrition. 2009 May 1;89(5):1704S-9S.
10. Reinhardt SL, Boehm R, Blackstone NT, El-Abbadi NH, McNally Brandow JS, Taylor SF, DeLonge MS. Systematic review of dietary patterns and sustainability in the United States. Advances in Nutrition. 2020 Mar 13.