Dairy consumption and cancer risk in Chinese adults are being examined in a research

Dairy consumption and cancer risk in Chinese adults are being examined in a research ...

Although all evidence to date on whether eating dairy products affects the risk of cancer has been inconsistent, studies on Western populations show that dairy products may be linked to a lower risk of colorectal cancer and a higher risk of prostate cancer, but there is evidence to be no clear connection for breast or other types of cancer. * These findings, however, may not be the same for non-Western populations, where amounts and types of dairy consumption and the ability to metabolize dairy products greatly differ.

In China, cheese and butter consumption is very low, and milk and yoghurt consumption is much lower than Western households. In addition, most Chinese adults are incapable of properly metabolizing dairy goods because of the lack of lactase, a key ingredient in reducing milk sugar lactose.**

Researchers fromOxford Population Health, Peking University, and the Chinese Academy of Medical Sciences in Beijing, have today published the results of a new large-scale study inBMC Medicine. These collected data from over 510,000 participants in theChina Kadoorie Biobank study.

Participants (59% female, 41% male) came from ten geographically diverse districts across China and participated in the study between 2004 and 2008. Each participant (aged 30-79 years) completed a questionnaire about how often they consumed different foods, including dairy products. The participants included regular dairy consumers (at least once a week) and people who never or rarely consumed dairy products (non-consumers).

Participants were followed-up for an average of 11 years, and the researchers used data from national cancer and death registries as well as health insurance records to identify new cancer diagnoses. Both fatal and nonfatal events were included. The data analyses weighed on several factors, including age, gender, gender, and family history of cancer, as well as socio-economic status (i.e. alcohol intake, smoking, physical activity, soy consumption, and fresh fruit intake), body mass index, chronic hepatitis B virus infection (

The study found that the following areas are being investigated:

  • Overall, around a fifth (20%) of the participants consumed dairy products regularly (primarily milk), 11% consumed dairy products monthly, and 69% were non-consumers. The average consumption was 38g per day overall in the whole study population and 81g per day among regular dairy consumers (compared with an average consumption of around 300g per day in participants from the UK Biobank).
  • During the study period 29,277 new cancer cases were recorded, with the highest rate being for lung cancer (6,282 cases), followed by female breast (2,582 cases), stomach (3,577 cases), colorectal (3,350 cases) and liver cancer (3,191 cases).
  • People who consumed dairy products regularly had significantly greater risks of developing liver and breast cancer. For each 50g/day intake, the risk increased by 12% and 17% respectively.
  • Regular dairy consumption was associated with an increased risk of lymphoma (though this was not statistically significant).
  • There was no association between dairy intake and colorectal cancer, prostate cancer, or any other type of cancer investigated.***

Both liver and breast cancer are among China''s most common types of cancer, accounting for around 393,000 and 368,000 new cancer cases each year. **** While these studies do not suggest causation, there are several valid biological mechanisms that may be able to explain these associations. For example, female sex hormones present in cows milk (such as oestrogen and progessterone) may have a role in the increased risk of breast cancer, while saturated and trans-fatty acids from dairy products may also be divided

This was the first significant study to investigate the relationship between dairy products and cancer risk in a Chinese population, according to Dr Maria Kakkoura, an epidemiologist at Oxford Population Health. Further research is needed to validate these current findings, to establish if these associations are causal, and to investigate the potential underlying mechanisms involved.

Although China''s average dairy consumption has been significantly lower than in European countries, it has also increased dramatically in recent decades.

While our findings suggest there may be a direct link between regular dairy consumption and certain cancers, it is important to be aware that dairy products are a source of protein, vitamins, and minerals. It would not be prudent to reduce dairy consumption based solely on the present study or without ensuring adequate intake of protein, vitamins, and minerals.

InBMC Medicine, this research is published.

Wellcome''s Livestock, Environment, and People Programme (LEAP) programme provided guidance on this type of work.

Meat, fish, and dairy products, and the Risk of Cancer. Continuous Update Project Expert Report 2018.

et al. The basis of a systematic review and meta-analysis of lactose malabsorption in adults. Lancet Gastroentrol Hepatol. 2017;2(10):738-46.

*** The complete list of site-specific cancer types examined by the study is: bladder, cervical, colorectal, endometrial, female breast, kidney, laryngeal, leukaemia, liver, lung, lymphoma, oesophageal, oral cavity, ovarian, pancreatic, prostate, and stomach.

**** Feng, RuiMei, and others on China''s current cancer situation: good or bad news from the 2018 Global Cancer Statistics? Cancer communication 39.1 (2019): 1-12.

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