To date, there has been little evidence that dairy products are effective in counteracting the ill effects of 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. These results may not be the same for non-Western populations with very different sizes and types of dairy consumption and their ability to metabolize dairy products.
In China, for example, consumption of cottage cheese and butter is very low, while consumption of milk and yogurt is much lower than in the West. In addition, many Chinese are unable to properly metabolize dairy products due to a lack of lactase, the main enzyme that breaks down lactose in milk sugar.
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.
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 a variety of 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 death registers, as well as health insurance records, to diagnose 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))).
- People who regularly consumed dairy products were at higher risk for liver and breast cancer. For each 50 g / day intake, the risk 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 gastrointestinal cancer, prostate cancer or other types of cancer.
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. Researchers say that while the results of this study do not prove causality, there are several plausible biological mechanisms that may 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. Investigate potential 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.
Associated Professor Huaydong Du, a senior researcher at Oxford Public Health and one of the study’s co-authors, added: you need to know that. It is unwise to reduce consumption without relying on the results of current research or ensuring adequate intake of protein, milk and minerals from other sources. “
The study was published BMC Medicine.
A new study links milk intake to the risk of breast cancer
Maria G. Kakkoura et al., An 11-year prospective study of 0.5 million people with general and site-specific cancer risks in dairy consumption and Chinese adults, BMC Medicine (2022). DOI: 10.1186 / s12916-022-02330-3
Submitted by Oxford University
Quote: Dairy products due to an increase in cancer (2022, May 6) May 8, 2022 https://medicalxpress.com/news/2022-05-dairy-products-linked-cancer.html
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