▎ WuXi AppTec content team editor
Once upon a time, meat was a "rare food" that people could only eat during the New Year's Festival; nowadays, although there is no meat in the meal, at least every three or five minutes you can open a meat, not only chicken and duck but also fish, pork is often eaten, and sometimes some lamb, beef or processed meat (such as bacon, sausage, fish balls, etc.) are eaten for taste.
However, eating too much meat is not only not good for health, but may also be harmful. Previous studies have found that eating meat often and eating more meat is associated with an increased risk of a variety of diseases, including ischemic heart disease, cerebrovascular disease, pneumonia, colonic diverticulosis and diabetes.
Recently, a study published in the Journal of Biomedical Center Medicine (BMC Medicine) added new evidence for the health benefits of eating meat in moderation. The study showed that eating meat no more than 5 times a week was associated with a lower risk of cancer, including overall cancer risk, as well as colorectal, postmenopausal, and prostate cancer risk.
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Researchers from the University of Oxford analysed data from the UK biobank and included 472377 participants aged 40-70 who did not develop cancer when they joined the study, 46% of whom were male and 54% female.
After the study began, the researchers counted the participants' dietary information, including vegetables, fruits, grains and meats. Meats include processed meats, beef, lamb, pork, chicken, turkey or other poultry, as well as fish such as oily and non-oily fish.
Based on the number of times the participants ate meat each week and the type of meat, the researchers divided the participants into 4 groups:
Eat meat regularly, eat meat 5 times a week>, and there is no limit to the type of meat;
Eat a small amount of meat group, eat meat ≤ 5 times a week, also unlimited type of meat;
Fish vegetarian group, eat only fish, do not eat other meat;
Vegetarian group, do not eat any meat.
In addition, the researchers collected information about the participants' height, weight, smoking, alcohol consumption and exercise, as well as information on the incidence of different types of cancer during follow-up.
The researchers statistically found that among the participants:
More than half (52.4%) ate meat > 5 times a week;
43.5% eat meat ≤ 5 times a week;
2.3% are fish vegetarians;
1.8% were vegetarians.
Fish vegetarians and vegetarians tend to have lower body mass index (BMI), younger age, and fewer unhealthy behaviors (e.g., smoking, alcoholism) than people who eat meat regularly and in small amounts.
During a follow-up period of an average of 11.4 years, a total of 54961 participants developed new cancers, of which 5882 had new colorectal cancer, 7537 female participants had new postmenopausal breast cancer, and 9501 male participants had new prostate cancer.
After removing other factors, the researchers found that eating meat in moderation or not eating meat was associated with a reduced risk of cancer. Specifically:
Compared with the participants in the meat-eating group who ate meat regularly, the participants in the small-amount meat group, the fish vegetarian group, and the vegetarian group had a 2%, 10%, and 14% lower overall cancer risk, respectively; the colorectal cancer risk was reduced by 9%, 16%, and 22%, respectively.
Compared with female participants in the group who ate meat regularly, female participants in the small meat group, fish vegetarian group, and vegetarian group had a 4%, 8%, and 18% lower risk of postmenopausal breast cancer, respectively.
Compared with the male participants in the meat-eating group who regularly ate meat, the risk of prostate cancer was reduced by 20% and 31%, respectively, compared to the male participants in the fish vegetarian group and the vegetarian group. The risk of prostate cancer in male participants in the small meat-eating group was not significantly different from that of male participants in the meat-eating group who regularly ate meat.
The researchers analyzed the association between eating little or no meat and reduced cancer risk, possibly related to a variety of factors:
Multiple studies have found that red meat is one of the risk factors for colorectal cancer, and people who regularly eat red meat are more likely to develop colorectal cancer;
People who eat less meat typically eat more plant-based foods, including fruits, vegetables, and whole grains, which may help reduce the risk of certain cancers;
People who eat less meat may have a lower weight and are less likely to develop obesity, which is a risk factor for more than a dozen cancers.
However, the relevant biological mechanism is not yet fully defined, and more research and exploration are needed.
Since the study was an observational study that only showed that eating meat in moderation or not eating meat was associated with a lower cancer risk, and did not show a causal relationship, the study also had some limitations, such as diet relying on participant recall, diet data was collected at a single point in time, not the participant's lifetime diet, etc., which may also have an impact on the findings.
However, the study concludes by highlighting that the study's findings add evidence to diet as one of the modifiable risk factors for cancer. But it should be noted that eating less meat or not eating meat does not necessarily make your diet healthier, and if you don't eat meat, but eat more ultra-processed foods, it is also harmful to health. If you want to reduce the risk of cancer through diet, you need to pay attention to the improvement and improvement of the overall diet.
So how to eat it helps reduce cancer risk?
According to the "Dietary Guidelines for Chinese Residents 2016", the daily diet should be done in the following aspects:
The daily diet should include cereals and potatoes, vegetables and fruits, livestock and poultry meat, eggs and milk, soybean nuts and other foods; eat more than 12 kinds of food every day, and more than 25 kinds of food per week.
Eat 250 g-400 g of cereals and potatoes per day, of which 50 g-150 g of whole grains and mixed legumes and 50 g-100 g of potatoes.
There are vegetables in the meal, at least 300 g-500 g per day, and dark vegetables should account for 1/2.
Eat fruit every day, eat 200 g-350 g fresh fruit per day, juice can not replace fresh fruit.
Eat dairy products every day, which is equivalent to 300g of liquid milk.
Eat soy products regularly and eat nuts in moderation.
Eat fish, poultry, eggs and lean meat in moderation, eat 280 g-525 g of fish per week, 280 g-525 g of livestock and poultry meat, and 280 g-350 g of eggs. Fish, poultry, eggs and lean meats are consumed on average 120 g-200 g per day, giving priority to fish and poultry, eating eggs without discarding egg yolks, and eating less fatty, smoked and cured meat foods.
No more than 6 g of salt per day, 25 g-30 g of cooking oil per day.
Control the intake of added sugars, no more than 50 g per day, preferably below 25 g.
The intake of trans fatty acids per day should not exceed 2 g.
Drink enough water, adults 7 to 8 cups (1500 ml-1700 ml) per day, advocate drinking boiled water and tea, do not drink or drink less sugary drinks.
In addition, it should also be noted that when cooking, try to use steaming, boiling, and frying to avoid roasting or frying. This is because in the process of roasting and frying, some carcinogens will also be produced, increasing the risk of cancer.
All in all, eating more meat and eating meat often is harmful to health, and eating meat in moderation is conducive to health. For overall health, meat and vegetables should be combined to achieve balanced and comprehensive nutritional intake.