Expert: Guideline needed to limit consumption of red, processed meats

In October, WHO released data suggesting an association between red or processed meats and an increased risk for colorectal cancer.

This report ― along with years of research on these types of meats and the associated cancer risk ― have experts questioning the most recent U.S. Dietary Guidelines, which do not include updated recommendations for the consumption of red or processed meats.

Susan Higginbotham, PhD, MPH, RD

HemOnc Today asked Susan Higginbotham, PhD, MPH, RD, vice president of research for the American Institute for Cancer Research (AICR), about the association between consumption of red and processed meats and cancer risk, as well as why she believes the U.S. Dietary Guidelines should include recommendations for the consumption of these types of meat.

Question: Does the consumption of red and processed meats cause cancer?

Answer: Yes. WHO’s most recent findings are in agreement with AICR’s expert report and our Continuous Update Project. We have a panel of experts who have found the evidence to be convincing that both red meat and processed meats are causes of colorectal cancer. For red meat, the risk is increased by about 18% per 100 grams of red meat per day. For processed meat, the risk is similar, but for 50 grams consumed per day. So, we welcome the WHO International Agency for Research on Cancer report.

Q: What do the scientific data suggest?

A: Overall, evidence consistently indicates that a diet high in red and processed meat increases the risk for colorectal cancer. This evidence is not from a single study or single population, but from a variety of studies conducted by different investigators and in different settings. AICR’s Continuous Update Project conducts systematic literature reviews that collects this information, synthesizes it and conducts meta-analyses. The main point I want to get across is that there is not just one single study reporting this increase in risk. There have been many studies over a number of years now.

Q: Why is this only coming to light now?

A: The link is not new. The reason it is getting attention now is because IARC issued this monograph. When IARC came out and called processed meat a carcinogen ― and red meat probably a carcinogen ― it made headlines. But this evidence about red and processed meat has been accumulating for the past 10 years or so. I think that it got a lot of attention this year because of the Dietary Guidelines Advisory Committee. Members looked at the evidence and advised the government to make a guideline to limit consumption of red and processed meat. They did not do this, but this was the advice based upon evidence.

Q: Is there something that farmers/suppliers of this type of meat can do to lower the cancer risk?

A: This is an important question and one that requires more research. There are a lot of theories as to why these meats increase risk, but nobody is sure yet. It could lie in the processing and the different chemicals that are added during processing, such as salting and smoking and curing for processed meats. It could be the heme iron in red meats. There are many different theories, but no solid evidence yet as to what it is that is causing this increase in risk. This is such an important question for the public, however. If manufacturers knew how to make their meat safer, everyone would benefit.

Q: What types of challenges are there in terms of bringing this information to the public? Should the U.S. Dietary Guidelines include information on the potential cancer risk associated with consumption of red or processed meats?

A: We at AICR do think that the Dietary Guidelines should have included this information. The evidence is out there, and their own advisory committee advised them to recommend limiting red and processed meat. The public is bombarded with nutrition information and the latest findings from individual studies, and it is hard to sort out what is important from what is just another soundbite. I think there is information fatigue and a growing sentiment, especially with nutrition information, that what you hear today may be contradicted tomorrow. It is important for the public to understand that AICR’s recommendations, WHO’s findings and the Dietary Guideline’s Advisory Committee advice are all based upon a thorough review of the totality of evidence. Although the finding of a 15% to 18% increased risk for colorectal cancer associated with eating this type of meat is relatively modest, it is an important finding because so many Americans do consume this meat daily.

Q: How much is too much? Should red and processed meats be eliminated entirely from the American diet?

A: AICR recommends that red meat be limited to no more than 18 ounces per week, so that’s about three to six servings per week. Processed meat should only be consumed on special occasions ― if at all.

Q: Do you have any final thoughts on this topic?

A: I would like to emphasize our take-home message to the public that diet does matter and some types of cancer can be prevented. By eating a healthy diet, maintaining a healthy weight and being physically active, we estimate that half of all colorectal cancers in the United States can be prevented. If people followed these guidelines, we estimate that a total of 340,000 cases of cancer could be prevented each year. These are not necessarily simple changes, but they are doable and can make a significant difference in cancer risk. – by Jennifer Southall

For more information:

Susan Higginbotham, PhD, MPH, RD, can be reached at s.higginbotham@aicr.org.

Disclosure: Higginbotham reports no relevant financial disclosures.