“A glass of milk a day, strong Chinese”, many people should have heard this slogan, many primary and secondary schools will also provide students with Milk snacks are provided. Drinking more milk can be said to have become a healthy consensus among Chinese people. But last week, a “milk carcinogen” study[1] hit the Internet. The study included 500,000 Chinese adults and was followed up for nearly 11 years. The results showed thatevery 50g of dairy products consumed per day was associated with a 7% increase in the risk of cancer and an increased risk of liver cancer. A 12% higher was associated with a 17% higher risk of breast cancer in women. Faced with such a result, people can’t help but ask, is this milk still drinkable?
What’s up with the “milk cancer” study?
Dairy products such as milk have long been considered to be anti-cancer foods, and many studies have proved that dairy products are effective against cancer, especially colorectal cancer. Protection[2]. However, most of these studies are aimed at Westerners, and Westerners and Chinese have huge differences in the metabolism of milk, such as rare in the Westlactose intolerancelactose intolerancelactose intolerancelactose intolerance strong>, but it affects about 90% of Asians[3] . In order to explore the relationship between the consumption of dairy products and the incidence of cancer among Chinese people, China Kadoorie Biobank, Peking University, Oxford University and other institutions jointly conducted research in Qingdao, Harbin, Five cities, Haikou, Suzhou, and Liuzhou, and rural areas in Sichuan, Gansu, Henan, Zhejiang, and Hunan provinces were surveyed, and a total of 512,726 people were included in the study. At baseline, the mean age of all participants was 52 years, 59% were female, 44% lived in cities, 20.4% consumed dairy products at least once a week, 68.5 % never or rarely consume dairy products. Overall, dairy consumption in urban areas is higher than in rural areas. Consumption of dairy products does help increase height, the study found. People who ate dairy products at least once a week were on average 0.6cm taller and had an average of 0.3cm longer legs than those who ate little dairy. Also, those who ate dairy were relatively lean, with a slightly lower BMI than those who ate little dairy. After an average of 10.8 years of follow-up, 29,277 of the 500,000 participants developed cancer. Regular consumption of dairy products was associated with a 9% higher risk of cancer, an 18% higher risk of liver cancer, a 22% higher risk of breast cancer in women, and a 23% higher risk of lymphoma, compared with little or no dairy consumption. However, after adjustment for multiple biasing factors, the association with lymphoma was no longer significant. On average, every 50g of dairy per day was associated with a 7% higher risk of cancer, a 12% higher risk of liver cancer, and a 17% higher risk of breast cancer in women . Also, similar associations were found across subgroups, regardless of whether they were male or female, young or old, and whether they lived in urban or rural areas.
Dairy intake is associated with increased risk of overall cancer, liver cancer, lymphoma and breast cancer in women The association of lymphoma is no longer significant after multiple adjustmentThe researchers also offer several explanations for this result: span>It starts withdiet patterns. Compared to the West, Chinese consumption of dairy products is generally lower and more plant-based foods are included in their daily diet. In a recent cohort study involving a high proportion of vegetarians and vegans who did not drink milk, dairy consumption was also positively associated with breast cancer risk< span lang="EN-US">[4]. Second,Chinese and Westerners also have different cancer profiles. In previous Western studies, the protective effect of dairy products on cancer was mainly reflected in colorectal cancer, while the incidence of colorectal cancer in China was significantly lower than that in the West. In this study, the incidence of liver cancer related to dairy products was found to be higher in China than in the West. In addition, dairy consumption increases blood insulin-like growth factor-1( IGF-1)horizontal[5], and higher IGF-1 levels are associated with an increased risk of some cancers, including breast cancer[6 ]. There are also a large number of lactose intolerant people in China, and their metabolism of milk may also be different, making the relationship between dairy products and cancer different from that in Western populations[6].
High proportion of lactose intolerant people in China
strong>Is it really impossible to drink milk?
Drinking milk does appear to be associated with an increased risk of cancer, according to research. However, it should be noted that this study is only an observational study, and the correlation between milk and cancer does not equal causation. Whether Chinese drinking milk increases the risk of cancer still needs more research. In addition, dairy products such as milk are an important source of calcium and have a certain protective effect on cardiovascular disease. Co-author Dr Huaidong Du from the University of Oxford also said: “While our research suggests that there may be a direct link between regular consumption of dairy products and some cancers, dairy products are also protein, Important source of vitamins and minerals. Based on current research alone, or without ensuring adequate intake of protein, vitamins and minerals from other sources, it would be unwise to reduce dairy consumption.”< span>
References:[1].Kakkoura MG, DuH, Guo Y, et al. Dairy consumption and risks of total and site-specific cancers in Chinese adults: an 11-year prospective study of 0.5 million people[J]. BMCmedicine, 2022, 20(1): 1-13.[2].Barrubés L, Babio N, Becerra-Tomás N, et al. Association between dairy product consumption and colorectal cancer risk in adults: a systematic review and meta-analysis of epidemiologic studies[J]. Advances in Nutrition, 2019, 10(suppl_2): S190-S211. [3].https://web.archive.org/web/20070421075017/http://www.gnxp.com/MT2/archives/001681.html[ 4]. Fraser G E, Jaceldo-Siegl K, Orlich M, et al. Dairy, soy, and risk of breast cancer: those confounded milks[J]. International journal of epidemiology, 2020, 49(5):1526-1537.< /span>[5].Har rison S,Lennon R, Holly J, et al. Does milk intake promote prostate cancer initiationor progression via effects on insulin-like growth factors (IGFs)? A systematic review and meta-analysis[J]. Cancer Causes & Control, 2017, 28 (6): 497-528.[6].Murphy N,Knuppel A, Papadimitriou N, et al. Insulin-like growth factor-1, insulin-like growth factor-binding protein-3, and breast cancer risk: observational and Mendelian randomization analyses with∼ 430 000women[J]. Annals of Oncology, 2020, 31(5): 641-649.[7].Shrier I,Szilagyi A, Correa J A. Impact of lactose containing foods and the genetics of lactase on diseases: an analytical review of population data[J]. Nutrition and cancer, 2008, 60(3): 292-300.< img class="content_title" data-galleryid="" data-ratio="0.4281391830559758" data-type="png" data-w="1322" layout="responsive" sizes="(min-width: 320px) 320px, 100vw" src="300,640" srcrc="https://mmbiz.qpic.cn/mmbiz_png/ZbHdNdNfVmlFI5rib89Hop4n6n1dWjwaZGJqZHJvN8cmv9CxPFxRPNrgbOXibAwVCSt5kSJQwXHqiaOUT05RdZggQ/640?wx_fmt=png">