A common link between climate change and health：Food
of Physicians (醫界蔬食聯盟)
According to the Fourth Assessment Report of the IPCC on Climate Change(1), the biggest source of global greenhouse gas emission is agriculture（food production）which account for more than one-third of all global greenhouse gas（GHG）emissions(2) (Figure 1), including livestock industry accounted for approximately 18% of human-induced GHG(3). Therefore, the FAO report in 2013 claims that we cannot ignore the potential effect of our daily food for mitigation of climate change(4).
In addition, based on the IPCC report in 2014, the global crop yield may drop 2% every 10 years due to climate change, while global food demand is expected to rise 14% every 10 years because of population growth(5). This shortage of food including water will certainly make the current situation of starvation and malnutrition worse and even cause conflicts within societies and between countries, because hunger breeds discontentment. The effects of food shortage are multiple including health and social impacts (Figure 1).
The relationship between food and health is also multifaceted. Food not only provide nutrition, but also affect our health status through changing intestinal microbiota, modulating gene expression, and influencing common cancers(6), ect. (Figure 1). Healthy food would provide more healthy nutrition (Figure 2) with less harmful ingredients(7,8,9,10), increase good probiotics in the intestine(11,12,13), modulate healthful gene expression (14) including lengthening the telomere(15), prevent and cure chronic diseases(16) and common cancers (Table 1), even stop epidemics of zoonotic diseases (Table 1). Food, thus, is a common link between climate change and health.
Furthermore, the 2010 report by the International Panel for Sustainable Resource Management of the UNEP concludes that the global shift to a vegan diet without meat, egg & milk is necessary to rescue our world from the worst impact of climate change, hunger and energy shortage, because the Western diet containing meat and milk products is not sustainable (17)! In fact, the ecological footprints of plant-based diets are much more sustainable than animal food(18) (Table 2). Convincing evidences have also shown that vegetarian dietary patterns make people living longer and healthy (Table 3). Therefore, plant-based diets are both sustainable and healthful and can be defined as sustainable food.
Sustainable food consumption can reduce greenhouse gas emission to gain more time for our adaptation to climate change. During the era of climate change, people have to make dietary adaptation in order to promote our health while decreasing chronic diseases and cancers which in turn can improve our tolerance to high temperature variability(19), and avoid social conflicts.
As medical professionals, we are duty-bound to need to promote sustainable food, because sustainable food is good for both climate change and human health (Figure 2). After all, healthy living (20) is the best revenge for climate change.
1. The Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4).
2. Agriculture and the climate change negotiations: an FAO perspective. Proceedings of the Symposium on Mitigation Greenhouse Gas Emissions from Animal Production. 2009/5.
3. Food and Agriculture Organization. Livestock’s long shadow–Environmental issues and options. 2006.
4. Food and Agriculture Organization. Tackling climate change through livestock: A global assessment of emissions and mitigation opportunities. 2013.
5. The Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5) Climate Change 2014: Impacts, Adaptation, and Vulnerability.
6. Grant W. A multicountry ecological study of cancer incidence rates in 2008 with respect to various risk-modifying factors. Nutrients 2014;6:163-189.
7. Zeneng Wang, Elizabeth Klipfell, Brian J. Bennett, et al. Gut flora metabolism of phosphatidylcholine promotes cardiovascular disease. Nature 2011; 472: 57-63.
8. K. Rak, D. J. Rader. Cardiovascular disease: The diet-microbe morbid union. Nature 2011;472(7341): 40–41.
9. Koeth RA, Wang Z, Levison BS, et al. Intestinal microbiota metabolism of l-carnitine, a nutrient in red meat, promotes atherosclerosis. Nat Med 2013;19(5): 567-585. doi:10.1038/nm.3145.
10. Tang WHW, Wang Z, Levison BS, et al. Intestinal microbial metabolism of phosphatidylcholine and cardiovascular risk. N Engl J Med 2013;368: 1575-84. doi: 10.1056/NEJMoa1109400
11. Wu GD, Chen J, Hoffmann C, Bittinger K, Chen YY, Keilbaugh SA,et al. Linking Long-Term Dietary Patterns with Gut Microbial Enterotypes. Science 2011; 334: 106-108.
12. David LA, Maurice CF, Carmody RN, et al. Diet rapidly and reproducibly alters the human gut microbiome. Nature 2014;505: 559-563. doi:10.1038/nature12820
13. Kim MS, Hwang SS , Park EJ, Bae JW. Strict vegetarian diet improves the risk factors associated with metabolic diseases by modulating gut microbiota and reducing intestinal inflammation. Environ Microbiol Rep. 2013;5: 765-775.
14. Ornish D, Magbanua MJM, Weidner G, et al. Changes in prostate gene expression in men undergoing an intensive nutrition and lifestyle intervention. PNAS 2008;105(24): 8369-8374.
15. Ornish D, Lin J, Chan JM, et al. Effect of comprehensive lifestyle changes on telomerase activity and telomere length in men with biopsy-proven low-risk prostate cancer: 5-year follow-up of a descriptive pilot study. Lancet Oncol. 17 September 2013. doi: 10.1016/S1470-2045(13)70366-8
16. Esselstyn CB Jr., Gendy G, Doyle J, Golubic M, Roizen MF. A way to reverse CAD? J Fam Pract. 2014;63: 356-364b.
17. International Panel for Sustainable Resource Management, UNEP. Assessing the environmental impacts of consumption and production Priority Products and Materials. 2010/6 http://www.unep.org/resourcepanel/Portals/24102/PDFs/ PriorityProductsAndMaterials_Report.pdf
18. Pimentel D, Pimentel M. Sustainability of meat-based and plant-based diets and the environment. Am J Clin Nutr 2003;78: 660s-663S.
19. Zanobettia A, O’Neillb MS, Gronlundb CJ, & Schwartza JD. Summer temperature variability and long-term survival among elderly people with chronic disease. PNAS 2012. doi:10.1073/pnas.1113070109
20. Ford ES, Bergmann MM, Kro¨ ger J, Schienkiewitz A, Weikert C, Boeing H. Healthy living is the best revenge: findings from the European Prospective
Investigation Into Cancer and Nutrition-Potsdam study. Arch Intern Med 2009; 169(15): 1355-1362.