red meat and cancer

red meat and cancer

red meat and cancer, Eating too much red and processed meat can increase your risk of developing a range of cancers, says a detailed eight-year study of nearly half a million people.

The study, which is the first to assess the overall risk from meat of developing a range of cancers, found that the people surveyed who ate the most were up to 60 per cent more likely to develop some types of cancer than those who ate the least.

"A particular strength of this study includes the large size of the cohort, which enabled us to investigate low-incidence cancers that have not previously been [assessed]," write the authors in the journal PLoS Medicine.To overcome the limitations of previous studies which have tested small numbers of people or collected data over shorter time frames, the epidemiologists led by Amanda Cross at the U.S. National Institutes of Health in Rockville, Maryland, recruited 494,000 people and collected data on many aspects of their lifestyle.

The study population consisted of men and women, aged between 50 and 71, none of whom had previously had cancer. In this study, red meat was classed as beef, pork or lamb.

The researchers compared the 20 per cent of participants who consumed the most meat to the 20 per cent who consumed the least. Statistical analysis of the data for red meat showed a 20 to 60 per cent increased risk of developing colorectal, liver, lung, and oesophageal cancers. A diet rich in processed meat was associated with a 20 per cent elevated risk for colorectal and a 16 per cent elevated risk for lung cancer.

The study controlled for the influence of a number of other lifestyle factors, which might also increase the risk of developing cancer, such as smoking.

Cross and her team suggest that certain carcinogenic compounds in meat – including N-nitroso compounds, heterocyclic amines, and polycyclic aromatic hydrocarbons – could be linked to the increased rates of cancer."There is no doubt there is a link between colorectal cancer and red meat, there are now over 20 studies all showing a similar risk," commented Peter Clifton, director of the Nutrition Clinic of Australian government research body, the CSIRO.

Ian Olver, with the Cancer Council Australia, in Sydney, points out that one limitation of the study is the lack of information about how the meat was prepared.

"With meat there are probably three things that are important," he said. "One is just the fat content of the meat, because we know that fat is associated with cancer. The second is how you cook the meat, because clearly if you barbeque the meat there will be more carcinogens than a slow cooked type of meat. And the third is how you preserve the meat; for example in southeast Asia where it is common to salt or smoke meat, we know you get carcinogens produced by those processes."

Another limitation of the study is that it didn't quantify how much meat the people in the highest consumption category where eating. It does however benefit from having a huge number of participants, Olver said.

Other studies have shown that eating fish decreases the risk of developing colorectal cancers, while the risks from white meats, such as chicken, appear to be lower. Overall, dietary factors are thought to contribute to around 35 per cent of cancers.

People who eat lots of red meat may have a higher risk of some types of kidney cancer, suggests a large U.S. study.

Researchers found that middle-aged adults who ate the most red meat were 19 percent more likely to be diagnosed with kidney cancer than those who ate the least. A higher intake of chemicals found in grilled or barbecued meat was also linked to increased risk of the disease, they reported in the American Journal of Clinical Nutrition.

“Red meat is an important source for iron (and) it has protein,” said Dr. Mohammed El-Faramawi, an epidemiologist from the University of North Texas Health Science Center in Fort Worth, who has studied diet and kidney cancer risks but wasn’t involved in the new study.“You should not stop eating red meat because there is an association between red meat and renal cancer,” he told Reuters Health. Instead, eating a limited amount of meat while following dietary recommendations is a good idea, he said.

U.S. guidelines call for limiting high-fat foods including processed meat, and instead eating more lean meat and poultry, seafood and nuts.

Eating red meat in large amounts — even if it doesn’t necessarily lead to kidney cancer — increases the risk of a host of health problems, such as plaque buildup in the arteries, El-Faramawi added.

Previous studies examining the link between red meat and kidney cancer arrived at mixed conclusions, according to Carrie Daniel, from the National Cancer Institute in Rockville, Maryland, and her colleagues.

To try to clear up that picture, they used data from a study of close to 500,000 U.S. adults age 50 and older, who were surveyed on their dietary habits, including meat consumption, and then followed for an average of nine years to track any new cancer diagnoses.

During that time, about 1,800 of them — less than half a percent — were diagnosed with kidney cancer.On average, men in the study ate two or three ounces of red meat per day, compared to one or two ounces among women. Participants with the highest consumption of red meat — about four ounces per day — were 19 percent more likely to be diagnosed with kidney cancer than those who ate the smallest amount, less than one ounce per day.

That was after accounting for other aspects of diet and lifestyle that could have influenced cancer risks, such as age, race, fruit and vegetable consumption, smoking and drinking and other medical conditions including high blood pressure and diabetes.

When the researchers looked at the most common types of kidney cancers, they found that the association between red meat and cancer was stronger for so-called papillary cancers, but there was no effect for clear-cell kidney cancers.

People who ate the most well-done grilled and barbecued meat — and therefore had the highest exposure to carcinogenic chemicals that come out of the cooking process — also had an extra risk of kidney cancer compared to those who didn’t cook much meat that way.

The study doesn’t prove that eating red meat, or cooking it a certain way, causes kidney cancer. And, El-Faramawi pointed out, some people who eat lots of red meat won’t develop cancer, while others that hardly eat any will.

Daniel and her colleagues said more research is needed to figure out why red meat may be linked to some types of kidney cancers but not others.

But for now, meat-related cooking chemicals “can be reduced by avoiding direct exposure of meat to an open flame or a hot metal surface, reducing the cooking time, and using a microwave oven to partially cook meat before exposing it to high temperatures,” Daniel told Reuters Health in an email.

“Our findings,” she concluded, “support the dietary recommendations for cancer prevention currently put forth by the American Cancer Society — limit intake of red and processed meats and prepare meat by cooking methods such as baking and broiling.”

Red meat and cancer are again linked in a recent study. It seems eating red meat contributes to a higher risk of dying from cardiovascular disease and cancer and all-cause mortality, says a study published online first in the Archives of Internal Medicine. The study found that people who substitute red meat with other foods, such as fish and poultry, are linked to a lower risk of mortality.

Dr. An Pan, Ph.D, of the Harvard School of Public Health, Boston, and team evaluated data from two prospective cohort studies, with repeated measures of diet and up to 28 years of follow-up, which included data from 37,698 men and 83,644 women. They noted 23,926 deaths, which included 5,910 deaths from cardio disease (CVD) and 9,464 deaths from cancer.

“We found that a higher intake of red meat was associated with a significantly elevated risk of total, CVD and cancer mortality, and this association was observed for unprocessed and processed red meat, with a relatively greater risk for processed red meat. Substitution of fish, poultry, nuts, legumes, low-fat dairy products and whole grains for red meat was associated with a significantly lower risk of mortality,” reports the team.

Some very interesting figures of the analysis showed that for one serving per day the risk of mortality increased by 12% for consuming total red meat, by 13% for unprocessed red meat and by 20% for processed red meat.The researchers found that a daily 100-gram serving of unprocessed red meat (about the size of a deck of cards) was associated with a 19% increased risk of type 2 diabetes. They also found that one daily serving of half that quantity of processed meat — 50 grams (for example, one hot dog or sausage or two slices of bacon) — was associated with a 51% increased risk. So processed red meat is certainly one to avoid. I had written about this in previous blogs

After analyzing meat substitutes, they estimated that replacing one daily serving of total red meat with one serving of either fish, poultry, vegetables, nuts, low-fat dairy products or whole grains lowered the mortality risk by 7%, 14%, 10%, 19%, 10% and 14% respectively, saying:

“We estimated that 9.3 percent in women of total deaths during follow-up could be prevented if all the participants consumed fewer than 0.5 servings per day of total red meat in these cohorts.”

So this study certainly makes it seem worth replacing that steak sometimes for a poultry- or vegetable-based dish. A reduction of 9.3% mortality for women makes a strong statement as far as I’m concerned.

I am a firefighter and cancer survivor circumnavigating the globe by bicycle to fund research for a cure for breast, prostate and lung cancer. The posted blogs are my personal opinion and thoughts.