Cancer Reserach Update

Linking Diabetes to Cancer: Changes for Prevention

March 21, 2012 | Issue 92

Also in this issue:

  1. In Brief: See Pastry; Love Your Meal More
  2. Half Your Burger, Live Longer?
  3. Exercise Affects DNA – Fast
  4. Childhood Cancer Survivors at Increased Risk of Obesity

Linking Diabetes to Cancer: Changes for Prevention

Karen CollinsDiabetes affects one of every ten American adults. A strong body of evidence now suggests that people with type 2 diabetes are at increased risk of developing several cancers. Yesterday, AICR Nutrition Advisor Karen Collins, MS, RD, CDN, co-presented a webinar on the connection between diabetes and cancer. Here, we asked Karen about what lifestyle steps people with type 2 diabetes, prediabetes, or anyone trying to prevent both diseases can do.

Q: What are the cancers people with type 2 diabetes are at increased risk for?

A: Research shows that the greatest increase in risk are cancers of the liver, endometrium, pancreas and bladder and non-Hodgkin's lymphoma. Liver cancer is two and a half fold risk and pancreatic is almost 75 percent higher. There's a smaller increase in risk for colon and breast cancers. But because those are the leading cancers in the United States, the fact that risk increases somewhat substantially for them means a lot more cancers.

Q: As more studies have come out on the diabetes-cancer link, what's new?

A: We're seeing more and more that the link makes sense and it's not just coincidental. As we're learning about how cancer development is linked to elevated levels of insulin and inflammation, it's becoming more apparent that the metabolic abnormalities in diabetes and prediabetes – before diabetes occurs – are the perfect conditions in the body for cancer to develop.

Q: About one-third of adults have prediabetes. How does this affect their cancer risk?

A: That's the scary part: the pre-diabetes that's happening with the increase in obesity and the sedentary quality of our lives. All the conditions common between type 2 diabetes and cancer don't just appear with a diabetes diagnosis.

Most people think the damage starts at diabetes. People are not thinking about cancer, they're worried about the damage that occurs from running high blood sugars, like going blind and kidney failure. But all those things happen way down the line with diabetes. The situation today matters.

Q: What are some first steps that people at risk or with diabetes can do to reduce their risk?

A: One of the top things is weight. For people who have been gaining weight, or have fat around their waists in particular then it's time to take action. If you have elevated triglycerides or your blood pressure is creeping up, these are signs that metabolically things are not right in your body.

You don't need a massive amount of weight loss. Research shows that for people who have pre-diabetes, even a 5 to 7 percent weight loss is enough to dramatically reduce their risk of developing diabetes. It doesn't mean going on a diet; take a look at your eating habits. Take a look at where you can cut 500 calories a day – it could be cutting a huge bottle of soda or having less cereal. You can stack up blocks of 100 calories scattered throughout the day.

"You're not going to lose weight in one day but it's a very positive thing to know that in one day's walk you are making a change in insulin resistance and other metabolic conditions that can make a big difference. "

Q: How does physical activity fit into the recommendations?

A: What's really exciting about the research in both diabetes and cancer is that exercising – like a 30 minute walk a day, all at once or in two to three blocks – will reduce inflammation and bring down insulin levels, which can have a dramatic effect. You will also probably feel so much better. You're not going to lose weight in one day but it's a very positive thing to know that in one day's walk you are making a change in insulin resistance and other metabolic conditions that can make a big difference.

Q: For people managing diabetes, how does counting carbs and the glycemic index relate to the diet for cancer prevention?

A: Counting carbs, with or without conscious attention to the glycemic index, can be essential for many people. But just because two foods are similar in glycemic index does not mean their total impact on health is the same. Often, if you focus on a high-fiber diet that includes plenty of vegetables, fruits, whole grains, and beans, you'll get all kinds of benefits for diabetes and cancer prevention.

This is all about looking beyond blood sugar. It's recognizing insulin resistance and inflammation and all these other things are important and seeing how foods can promote health and reduce your risk of cancer.

Q: Should a person with diabetes be doing something different if he knows he's at higher risk for cancer?

A: These people, of all people, should not be falling behind on their cancer screenings. The consensus report looked at whether medical treatment would change: the answer was no. In fact, one of the most common first-line treatments for type 2 diabetes is metformin, and it may actually help to reduce cancer risk.

Q: And for diet and exercise?

A: Having diabetes really reinforces, 'don't delay, get on this' – you can sometimes be so overwhelmed with a diagnosis of diabetes that people take their time. You can get blood sugar controlled by more medication but that's not as good in terms of overall long-term health as combining medical treatment and healthy weight and lifestyle choices. It's better to say, I'm not going to lose 50 pounds but lets get on the stick and lose 10. I'm going to start toward a 30-minute walk now.

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Q: How does heart disease fit into all this?

A: That's the interesting parallel. It's been known for a while that people with type 2 diabetes are at dramatically increased risk for heart disease. Now that we know they are at increased risk for some types of cancer, with a few tweaks you can have a unified pattern of eating to reduce risk for all three.

AICR recommendations line up well with those of AHA (American Heart Association) and ADA (American Diabetes Association). There are things like red meat. In diabetes control they don't differentiate between red meat and other choices, like chicken or fish. We would recommend less than 18 ounces of red meat, even if lean, to prevent colorectal cancer. It's a pretty positive thing to know that small changes can have the triple-effect – reduce the risk of type 2 diabetes, heart disease and cancer.

AICR/AADE Webinar (Archived): The Diabetes-Cancer Connection: From Research to Practice
Offered in collaboration with American Association of Diabetes Educators. Presenters are: Karen Collins, MS, RD, CDN and oncologist Michael Pollak, MD.
CE Credits

Follow Karen on her blog.

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Food Photos on a tableIn Brief: See Pastry; Love Your Meal More

Seeing pictures of a decadent high-calorie pastry while eating may make you enjoy your low-calorie food more, suggests a small new brain study published in PLoS ONE.

The study, conducted by researchers at the Nestlé Research Center in Switzerland, showed food photographs to 14 participants. Photos were either of high-calorie foods, such as pastries, pizza, and lamb-chops or low-calorie foods, such as watermelon, yogurt and beans. Participants were then given an unfamiliar metallic-like taste, which involved passing a light electric current on their tongue.

After seeing the high-calories foods, participants were more likely to rate the electric taste more enjoyable than compared to the low-calorie images. The images also affected brain activity. An EEG showed that visual images affected regions of the brain related to sensory perception.

Sources: Ohla K , Toepel U , le Coutre J , Hudry J (2012) "Visual-Gustatory Interaction: Orbitofrontal and Insular Cortices Mediate the Effect of High-Calorie Visual Food Cues on Taste Pleasantness." PLoS ONE 7(3): e32434. doi:10.1371/journal.pone.0032434.

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Research Roundup

Half Your Burger, Live Longer?

raw Red Meat slabs A daily serving of red meat may shorten your life but substituting that meat with chicken, fish or another protein may extend it, suggests a study published last week in the Archives of Internal Medicine.

The Harvard University study pulled data from approximately 120,000 participants. The men were from the Health Professionals Follow-up Study, which began in 1986; the women were part of the Nurses' Health Study, which began in 1980. Everyone was cancer and heart disease free when the study began.

Participants filled out questionnaires about their eating habits at the start of the study and then every four years.

The study focused on red meats and mortality, looking at death from any cause, heart disease, and cancer. After tracking participants for up to 28 years, the researchers found that one daily serving of unprocessed red meat linked to a 13 percent increased risk of death during the course of the study. One daily serving of processed red meat, such as a hot dog or two slices of bacon, linked to a 20 percent increased risk. Bacon and hot dogs linked to a higher risk than other items.

For cancer specifically, the increase in mortality risk was 10 percent for unprocessed red meat and 16 percent for processed red meat. Earlier death for heart disease was 18 percent and 21 percent increase in risk, respectively.

In calculations, the authors estimated that almost 10 percent of deaths in men and 8 percent in women could be prevented during the course of the study if everyone ate less than half a serving per day (approximately 42 grams) of red meat.

Replacing a daily red meat serving with poultry linked to a 14 percent lower risk, a 19 percent lower risk for nuts, 7 percent lower risk for fish and 10 percent for legumes.

The findings add to the body of evidence on red meats and cancer. AICR's latest Continuous Update Project (CUP) report released last year concluded that consuming too much red and processed meat increases the risk of colorectal cancer.

Sources: An Pan; Qi Sun, Adam M. Bernstein, Matthias B. Schulze, JoAnn E. Manson, Meir J. Stampfer, Walter C. Willett, Frank B. Hu. "Red Meat Consumption and Mortality." Arch Intern Med. Published online March 12, 2012

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Exercise Affects DNA – Fast

leg musculatureAmong inactive people, a few minutes of exercise can immediately affect which genes turn 'on' and 'off' in muscle DNA, according to a study published in Cell Metabolism last week.

The study looked at compounds called methyl groups that attach to DNA. When methyl groups bind to DNA they can change which genes are expressed.

After 14 inactive men and women did a bout of exercise, study researchers found their skeletal muscle DNA had fewer methyl groups compared to before they exercised. The DNA changes took place in areas of DNA involved in turning "on" genes important for muscles' adaptation to exercise.

In order to better understand the effects of exercise, the researchers then conducted an experiment with muscle in lab dishes. They exposed muscles to caffeine, which produces similar gene expression as exercise, and saw a similar loss of DNA methyl groups. The findings offer more evidence that environmental changes can alter our genome in ways that can affect health.

Sources: Romain Barrès, Jie Yan, Brendan Egan, Jonas Thue Treebak, Morten Rasmussen, Tomas Fritz, Kenneth Caidahl, Anna Krook, Donal J. O'Gorman, Juleen R. Zierath. Acute Exercise Remodels Promoter Methylation in Human Skeletal Muscle. Cell Metabolism, 2012; 15 (3): 405 DOI: 10.1016/j.cmet.2012.01.001.

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Childhood Cancer Survivors at Increased Risk of Obesity

Bald Child survivor with a Daffodil After children recover from cancer they are at a greater risk of chronic health conditions, and obesity, which puts them at increased risk for cancer along with other diseases. Cancer-related treatment may play a role in being an overweight adult, while being physically active and having a relatively standard amount of cancer-related anxiety deceases the risk, suggests a recent study published in the Journal of Clinical Oncology.

The study drew from almost 9,300 childhood cancer survivors who were at least 18 years old at the time of the follow-up questionnaire in 2003. More than 60 percent of the young adults were diagnosed with cancer when they were younger than 10.

Children diagnosed at ages 5 through 9 was one of the factors that increased risk for obesity, compared to other age groups, the study found. Poor physical function among the survivors was the strongest predictor of obesity. Increased cancer-related pain, anxiety, and inactivity all were predictors of poor physical function. More than a third of the survivors reported some degree of cancer-related anxiety and almost a quarter had cancer-related pain.

Taking a specific drug that helps treat depression was also linked to obesity.

Increasing motivation and the ability for survivors to be physically active is one of the study's conclusions. Activity reduced risk of obesity and previous studies have shown childhood cancer survivors are relatively inactive, this research suggests.

Source: Green DM, Cox CL, Zhu L, Krull KR, Srivastava DK, Stovall M, Nolan VG, Ness KK, Donaldson SS, Oeffinger KC, Meacham LR, Sklar CA, Armstrong GT, Robison LL. "Risk factors for obesity in adult survivors of childhood cancer: a report from the Childhood Cancer Survivor Study." J Clin Oncol. 2012 Jan 20;30(3):246-55.

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