Dairy products associated with increased risk of cancer in the main study

According to a large study of Chinese adults’ consumption of dairy products and the risk of cancer, increased consumption of dairy products is associated with liver cancer and breast cancer in women.

The first major study to study dairy consumption and cancer risk in adults in China found that high intake was associated with increased risks of liver cancer and breast cancer in women.

To date, there is no conclusive evidence that dairy products affect cancer. Studies on Western populations show that dairy products may be associated with a lower risk of gastrointestinal cancer and a higher risk of prostate cancer, but no clear link has been found for breast or other types of cancer.[1] These results, however, may not be the same for non-Western populations whose sizes and types of dairy consumption and their ability to metabolize dairy products are quite different.

In China, for example, consumption of cottage cheese and butter is very low, while consumption of milk and yogurt is much lower than in Western countries. In addition, many Chinese adults are unable to properly metabolize dairy products due to a lack of lactase, the main enzyme that breaks down lactose in milk sugar.[2]

Researchers at Oxford Public Health, Peking University and the Chinese Academy of Medical Sciences have released the results of a new large-scale study in Beijing today to determine whether dairy products have a different effect on cancer in the Chinese. BMC Medicine. It collected data from more than 510,000 participants in China’s Kadoorie Biobank study.

Dairy products Cancer risk

Oxford University

Participants (59% females, 41% males), from ten different geographical regions of China and joined the study between 2004 and 2008, had no previous history of cancer. At the time of recruitment, each participant (30-79 years old) filled out a questionnaire on how much they ate different foods, including dairy products. Researchers divided participants into three groups: regular consumers of dairy products (at least once a week), consumers of dairy products, and people who have never consumed dairy products on a monthly or infrequent basis (non-consumers).

Participants were monitored for an average of 11 years, and the researchers used data from the National Cancer and Mortality Register, as well as health insurance records to identify new cancers. Includes fatal and non-fatal events. The data analysis takes into account a number of other factors that may affect the risk of cancer, including age, gender, region, family history of cancer, socioeconomic status (i.e. education and income), and lifestyle factors (i.e. .drinking alcohol, smoking, physical condition). activity, soy consumption and consumption of fresh fruits), body mass index, chronic hepatitis B virus infection (for liver cancer) and female reproductive factors (for breast cancer).

The study found:

  • Overall, one-fifth of participants (20%) consumed dairy products regularly (primarily milk), 11% consumed dairy products on a monthly basis, and 69% did not consume them at all. The average consumption was 38 g per day in the general study population and 81 g per day among regular consumers of dairy products (compared to the consumption of approximately 300 g per day in the UK Biobank participants).
  • During the study period, 29,277 new cancers were registered, with the highest rates of lung cancer (6,282 cases), followed by breast (2,582 cases), gastric (3,577 cases), colon (3,350 cases) and liver cancer (3 cases). 191) cases). cases).
  • People who regularly consumed dairy products were at higher risk for liver and breast cancer. The risk for each 50 g / day intake increased by 12% and 17%, respectively.
  • Regular consumption of milk is associated with an increased risk of lymphoma (this is not statistically significant).
  • There was no association between milk intake and colorectal cancer, prostate cancer or other types of cancer.[3]

Liver and breast cancer is one of the most common types of cancer in China, accounting for 393,000 and 368,000 new cases of cancer each year, respectively.[4] Although the results of this study do not prove the cause, the researchers say that there are several reasonable biological mechanisms that can explain these compounds. Increased consumption of dairy products, for example, increases insulin-like growth factor-I (IGF-I) levels, which promotes cell proliferation and is associated with a higher risk for several types of cancer. Potentially, female sex hormones (such as estrogen and progesterone) in cow’s milk increase the risk of breast cancer, while saturated and trans fatty acids from dairy products increase the risk of liver cancer. For most Chinese who do not produce enough lactase, dairy products can also be broken down into foods that can cause cancer.

Dr. Maria Kakkoura, an Oxford nutritionist and the first author of the study, said: “This is the first major study to examine the link between dairy products and cancer risk in the Chinese population. Additional research is needed to confirm these current findings, to determine if these associations are causal, and to investigate possible underlying mechanisms.

The average level of consumption of dairy products in China remains much lower than in European countries, but in recent decades it has grown rapidly.

Huaydong Du, a senior Oxford public health researcher and co-author of the study, added: “Although our findings suggest that there may be a direct link between regular milk consumption and some cancers, these important dairy products are a source of protein, vitamins and minerals. you need to know that. It is unwise to reduce milk consumption without relying on the results of current research or ensuring adequate intake of protein, vitamins and minerals from other sources.

The study was published BMC Medicine.

Reference: “Dairy Consumption and General and Site Cancer Risks in Chinese Adults: An 11-Year Prospective Study of 0.5 Million People,” Maria G. Kakkoura, Huaidong Du, Yu Guo, Kanqing Yu, Ling Yang, Pei Pei, Yiping Chen, Sam Sansome, Wing Ching Chan, Xiaoming Yang, Lei Fan, Jun Lw, Junshi Chen, Liming Li, Timothy J. Kei and Zhengming Chen on behalf of the Joint Group of Kadoori Biobank (CKB) of China, May 6, 2022, BMC Medicine.
DOI: 10.1186 / s12916-022-02330-3

This work was supported by Wellcome under the Livestock, Environment and People (LEAP) program.

Notes

  1. World Cancer Foundation / American Cancer Research Institute. Meat, fish and dairy products and cancer risk. Expert Report of the Continuous Update Project 2018.
  2. “Country, Regional, and Global Assessment for Lactose Malabsorption in Adults: A Systematic Review and Meta-Analysis” by Christian Lovold Storhaug, MS; Svein Kjetil Fosse, MS and Dr Lars T Fadnes, PhD, 6 July 2017,

Leave a Comment

Your email address will not be published.