Cancer & Metastasis Current Global News
A study out Wednesday suggests eating a lot of highly processed foods might be associated with higher rates of cancer. The study appears in BMJ, and the authors admit more study is needed, but warn that the rapid adoption of what they call “ultra-processed foods” may increase the cancer burden in the coming decades.
We asked Marji McCullough, SCD, RD, strategic director of nutritional epidemiology for her thoughts on the study.
“This was a well-conducted study but we should be cautious about interpreting what exactly is responsible for the higher cancer risk. For example, people eating more highly processed foods are eating fewer healthy foods that may reduce the risk of cancer.
“Highly processed foods are frequently packed with sugar, salt, fat and calories. The authors did try to control for these factors, but it’s difficult to totally control for these and other dietary components.
“Of note, a large proportion of the highly processed foods in this study were sugary products and beverages, which contribute to weight gain and add little nutritional value to the diet.
“In addition, people who eat more highly processed foods tend to have other unhealthy dietary and lifestyle behaviors which might not have been fully accounted for in this study.
“We know people who eat more processed and red meat, potatoes, refined grains, and sugar sweetened beverages and foods are at a higher risk of developing certain cancers. It’s still unclear what role processing has in this relationship; more research on this will be done to more carefully tease out this risk.
“In the meantime, this is one more piece of evidence that a diet rich in whole grains, whole fruits and vegetables, as recommended in the American Cancer Society guidelines, is beneficial for lowering cancer risk.”
Marji also had an important tip for shoppers: “Focus your shopping on the perimeter of the grocery store,” she says. “That’s usually where the whole foods tend to be; vegetables, fruit, whole grains, etc.”
Preliminary data was released today from two rodent studies by the National Toxicology Program (NTP), to explore potential links between cell phones and cancer. The studies have found high exposure to radiofrequency radiation (RFR) resulted in tumors in tissues surrounding nerves in the hearts of male rats, but found no link in female rats nor in any mice. As is commonly done in these types of studies, researchers used exposure levels that were higher, and often far higher, than the amounts typically emitted by cell phones.
The authors say the new data does not go much further than what they reported in 2016.
Below are comments from Otis W. Brawley, M.D., in response to the new data.
“These draft reports are bound to create a lot of concern, but in fact they won’t change what I tell people: the evidence for an association between cell phones and cancer is weak, and so far, we have not seen a higher cancer risk in people. But if you’re concerned about this animal data, wear an earpiece.
“Perhaps the most important thing to take away from today’s news may be this line from the press release:
“The levels and duration of exposure to RFR were much greater than what people experience with even the highest level of cell phone use, and exposed the rodent’s whole bodies. So, these findings should not be directly extrapolated to human cell phone usage,” said John Bucher, Ph.D., NTP senior scientist.
“The animals in this study were exposed at high levels for 9 hours per day. So while the link to some rare cancers are important, there is no reason to think this study reflects real life exposures.
“Dr. Bucher confirmed this in a press conference with reporters, and when asked whether the new data has changed how he uses cell phones, he replied that it has not, nor has he told his family to change what they do.
“Some additional cautions: as one of the reporters on the press conference pointed out, while some radiated animals did indeed have more tumors, in fact they lived longer. Also, it’s far from a slam dunk to apply findings in one species to another. Also, these studies were negative for common tumors, which is somewhat comforting. It suggests if anything, cell phone radiation may (and only “may”) be linked to some very rare tumors. And newer, lower energy cell phones, and more cell towers are likely to make exposures even lower.
“A final point to remember is that we should not base our decisions or our point of view on a single study. When deciding where the truth lies, you really need to take all the available evidence into account. And in fact, most studies looking into cell phones and cancer are negative.”
A study published this week in Science reports promising results of a blood test designed to detect eight common cancer types by measuring circulating proteins and mutations in cell-free DNA. The study comes from the Johns Hopkins Kimmel Cancer Center at Johns Hopkins and has created a lot of buzz. We asked J. Leonard Lichtenfeld, M.D., MACP, deputy chief medical officer to share his thoughts about the study.
“The study reported this week on the potential of cell free DNA providing another option for the early detection of cancer represents elegant science. It is one more step down what we expect to be a long path of discovery to determine if this approach is not only effective at early detection but, far more important, also improves outcomes for those diagnosed with cancer.
“The test is one of several approaches with a similar focus on the early detection of cancer. Which tests will achieve this goal is not certain at this time.
“It is important to remember that it is one thing to advance the science and the technology; however it is something entirely different to demonstrate that the test will actually make a difference in saving lives. Notwithstanding the results of this study in patients who have already been diagnosed with cancer, it is possible that we may find that the test will find cancers early and we won’t be able to accurately determine where the cancer came from. Or we may learn that simply find these cancers early may not make treatment more effective or impact lives to the degree we had hoped for. These are answers we need.
“In simpler terms: we have a long way to go to demonstrate the utility and value of this test. We cannot make assumptions regarding the ability of this test to detect cancer early based on this study. We need additional research (which is being undertaken) to prove that it is possible to find cancer signals in the blood of patients before it is otherwise known they have cancers. Those studies are moving forward at this time.
“We have made assumptions in the past about the ability of blood tests to diagnose cancer early with—for example–tests for prostate and colon cancers. The prostate cancer experience should teach us that we need to prove value and utility before we again subject potentially millions of people to possibly unnecessary medical procedures and treatment which ultimately have not necessarily improved the length or the quality of their years.”
A study in today’s JAMA Oncology links diets that include foods that can cause inflammation to an increased risk of colorectal cancer. Those foods include meats, refined grains, and high-calorie beverages. We asked Marji McCullough, SCD, RD, strategic director of nutritional epidemiology at the ACS.
“There has been a lot of interest in the role of diet in inflammation, and in fact several anti-inflammatory diets have begun to be promoted. This is an observational study, not interventional, so it has some limitations, but it does shed some light on the issue.
“There are several ways diet may influence colorectal cancer risk, including inhibiting or promoting inflammation, which is the focus of this paper. Chronic inflammation can cause DNA damage and lead to unregulated cell growth. Other ways diet could influence colorectal cancer risk is through antioxidant effects (protecting against DNA damage), influencing the cell cycle, and direct consumption of carcinogens.
“While it’s tempting to focus on specific foods, how overall diet contributes to this inflammatory effect is likely more important than individual foods because foods may act together in influencing disease risk.
“It’s possible the impact of diet is even greater than that measured in the current study, which captured only some of the foods that are likely to influence inflammation. For example, certain spices and food preparation methods that were not included may have strong effects on inflammation.
“It’s interesting to consider that what you eat may be just as important as what you don’t. In other words, many foods and beverages are substitutions for each other. One strength of this paper is that it takes the total diet into account.
“Another important aspect of this study is that it focused on foods, not supplements. It underscores how food can have significant roles in influencing disease risk.
“As far as what people should know about colorectal cancer and diet: The International Agency for Research on Cancer (IARC) determined that processed meat is a carcinogen, and red meat is a probable carcinogen, so lower intakes of both would reduce colorectal cancer risk. Whole grains and (low fat) dairy foods are associated with lower risk of colorectal cancer. Whole grains add bulk to the diet and may dilute carcinogens. Whole grains and other plant foods also contribute to beneficial microbiome diversity. Dairy foods contain calcium and vitamin D, which have beneficial effects on cell proliferation and differentiation.
“The bottom line: It’s important to consider the total diet, as a combination of lots of healthy foods and lower amounts of unhealthy foods are likely to have additive and synergistic effects on lowering cancer risk.”