Processed Meat Consumption and CHD, diabetes and colorectal cancer
Growing evidence suggests that processed meats are particularly adverse for cardiometabolic health, perhaps attributable to their far higher levels of preservatives (especially sodium), for example, Micha et al. (2012) conducted meta-analyses of prospective cohorts and found a higher risk of coronary heart disease (CHD) with processed meat consumption (Relative Risk per 50 g: 1.42, 95 %CI = 1.07–1.89). The World Health Organization’s (WHO) International Agency for Research on Cancer (IARC) has even classified processed meat as carcinogenic (Group 1) to humans because of an association with colorectal on 26 October 2015.
Two recent studies also found the relative risk of colorectal cancer and cardiovascular death as a function of the average intake of processed meat (Figure 1). The increased risk of colorectal cancer is clear and strong, it is estimated that an intake of 26.5g processed meat (average of Western Europeans’ consumption) would lead to a 9% increase in colorectal cancer risk. (Godfray et al., 2018 cited IARC results), and intake of 50g of processed meat per day increases the risk of colorectal cancer by 18%. (Yau, 2019 cited IARC results) It is also estimated "that 34,000 cancer deaths per year worldwide are attributable to diets high in processed meat" (Godfray et al. 2018).
How many grams per day of processed food can be eaten?
Figure 2 reports the observed consumption levels of processed meats associated with the lowest disease risk in meta-analyses as follows: 0.07 serving/day (CHD), 0.11 serving/day (diabetes), 0.12 serving/day (colorectal cancer) — 50g/serving. That implies not more than 3.5g/day, and only South Koreans achieved (Column 4 of Figure 2).
In fact, the mean global intake of processed meat was 13.7 g/day (Micha et al. 2015), which is 4-time more than the lowest disease risk. Central Latin Americans consume the most (44.4 g/day), and East Asians consume the least (4.1 g/day). China is said to be the country with one of the lowest consumption rate (3.9g/day) of processed meat as shown in Figure 1, however, from my personal experience, Hongkongers are consuming much more than that.
Unfortunately, there is no data about the consumption quantity of processed meat in Hong Kong. The two surveys on the consumption habit of processed meat by the Centre of Health Protection in 2009 and 2016 (CHP, 2019a) are based on the number of times per week rather than the weight of consumption. (Figures 3 and 4)
The two surveys clearly show an increasing consumption frequency, especially by male respondents, on processed meat. For example, there was 13.0% male who consumed processed meat 4 or more days per week, and it increased to 15.3% in 2016.
Coincidentally, the incidence rate of colorectal cancer in Hong Kong is also rising steadily. Figure 4 shows the age-standardized incidence rate of colorectal cancer from 1983 to 2016, and the increasing trend is clear in the male population. It grows from less than 40 per 100,000 male persons in 1983 to more than 50 per 100,000 male persons in 2016. Interestingly, there is no such trend of increase in the female population. Would it be the consequence of the increasing consumption of processed meat by the male, ceteris paribus? It may be a good thesis for further study.
Yau, A. (2019) Processed Meat, Red Meat and Cancer, Food Safety Focus (113th Issue, December 2015), Centre for Food Safety, HKSAR Government. https://www.cfs.gov.hk/english/multimedia/multimedia_pub/multimedia_pub_fsf_113_01.html
CHP (2019a) HK Consumption of Processed Meat 2009 and 2016, Statistics on Behavioural Risk Factors, Centre for Health Protection, HKSAR Government. https://www.chp.gov.hk/en/static/24016.html
CHP (2019b) Colorectal Cancer, Centre for Health Protection, HKSAR Government. https://www.chp.gov.hk/en/healthtopics/content/25/51.html
Godfray, H.C.J., Aveyard, P., Garnett, T., Hall, J.W., Key, T.J., Lorimer, J., Pierrehumbert, R.T., Scarborough, P., Springmann, M. and Jebb, S.A. (2018) Meat consumption, health, and the environment, Science, Jul. 360, no. 6399. https://doi.org/10.1126/science.aam5324
Micha R, Michas G, Mozaffarian D (2012) Unprocessed red and processed meats and risk of coronary artery disease and type 2 diabetes — an updated review of the evidence. Curr Atheroscler Rep 2012;14:515–24. doi:10.1007/s11883–012–0282–8
Micha R, Khatibzadeh S, Shi P on behalf of the Global Burden of Diseases Nutrition and Chronic Diseases Expert Group (NutriCoDE), et al (2015) Global, regional and national consumption of major food groups in 1990 and 2010: a systematic analysis including 266 country-specific nutrition surveys worldwide, BMJ Open 2015;5:e008705. doi: 10.1136/bmjopen-2015–008705