There are plenty of reasons why broccoli is good for us. But it was 20 years ago, with AICR support, that Paul Talalay found one concrete way these cruciferous vegetables protect against cancer. It was Talalay who identified sulforaphane from broccoli, and went on to show its cancer protective properties. Now a Professor at Johns Hopkins University, Talalay's research in cruciferous vegetables continues to answer questions as to how these foods play a role in cancer protection.
Q: You were trained as a surgeon. How did you become interested in cancer prevention?
A: I've been interested in the cancer problem all my life. I saw my first cancer patient when I was in medical school. But I realized treatment and prevention are, in fact, part of the same disease process. It's just a question of timing. The silent, pre-diagnostic period is the best opportunity for prevention. My mission was to treat the disease before the diagnosis.
Q: When did you first start looking at dietary factors and cancer risk?
A: I turned my attention to prevention in the late 1970s. What became clear was that chemicals in our foods considered benign could prevent the carcinogenic effects of other chemicals. Things we were eating already could stop cancer. We began to study them.
Q: What did you discover?
A: We discovered that our cells have developed elaborate systems to protect themselves. We found that the food's [antioxidants] raised the intrinsic mechanisms that cells used to protect themselves. Instead of creating novel new systems, we use what nature gave us.
"Things we were eating already could stop cancer.
We began to study them."
Q: How did you start looking at cruciferous vegetables, like broccoli?
A: One evening in the early '80s, a PhD student said, "everyone says if you eat a lot of vegetables you'll avoid a lot of disease." I gave him $20, he went down to Northeast Market and brought back to the lab a bunch of vegetables and other foods. We used a bioassay we had developed that measured the activity of one member of the cell's protective system – an enzyme. Among the things you could buy in the grocery store, the crucifers were particularly effective at increasing these protective mechanisms. This led to the isolation of the most important of these compounds in broccoli: sulforaphane.
Q: The idea that the body is capable of protecting itself from various carcinogens by diet must have been revolutionary. What did the scientific community think?
A: There has not been much "wowing" because [the discovery process] has occurred in a stepwise fashion – an incremental, slow process. We have since built evidence on how cruciferous compounds can reduce risk of cancer on all fronts: the mechanistic, utility and therapeutic fronts. Now we're conducting clinical trials.
Q: Some of your more recent research has looked at how heat affects phytochemicals. What have you found?
A: Plants do not contain the active component like sulforaphane; they contain a precursor, which is an inactive form. When you chew the plant or prepare it for a meal by cutting it, you release an enzyme that makes the compound active. When you cook plants, you kill this enzyme.
By some quirk of nature our gastrointestinal microflora contains the same enzyme that produces this final active product. But crucifers are particularly rich [in the precursors] and we found that raw crucifers are much more effective than cooked.
Q: You were one of AICR's earliest grantees, which is exciting for us because you were such a visionary in the diet-cancer field.
A: On the contrary – what a visionary they were! AICR has provided continuous support for our lab for nearly 20 years.… In retrospect, AICR has been involved in nearly all of the central contributions of our laboratory.
Excerpted from Winter 2012 ScienceNow.
Two women dining together are likely to start eating in synch with one another, especially at the beginning of meals, suggests a new study published in PLoS ONE.
For the study, researchers observed 70 pairs of young women, who had signed up to participate in a study on portion size. The women sat across from one another and were served a meal. For 20 minutes, the researchers noted the number and timing of bites the women took by observing them through a hidden camera tucked into a lamp.
For the most part, within five seconds of one woman taking a bite her dining companion followed suit. Both women mimicked each other's eating behavior. The mimicry was more prominent at the beginning than at the end of the meal. This study suggests that behavioral mimicry may partially account for social modeling of food intake.
Source: Hermans RCJ, Lichtwarck-Aschoff A, Bevelander KE, Herman CP, Larsen JK, et al. (2012) Mimicry of Food Intake: The Dynamic Interplay between Eating Companions. PLoS ONE 7(2): e31027. doi:10.1371/journal.pone.0031027
The study, published last week in BMJ Research, pulled together all relevant randomized controlled trials (RCTs), considered one of the most reliable and informative types of studies. In RCTs, participants are randomly assigned to the treatment exercise in this case or non-treatment group and then tracked for the same period of time.
This analysis looked at 34 RCTs that evaluated how exercise affected adult cancer patients. Almost two-thirds of the studies focused on breast cancer survivors; the others examined prostate, gynecologic, colorectal, gastric or lung cancer. Studies included aerobic, resistance and strength training with the survivors active anywhere from 3 to 60 weeks, depending upon the study. (Thirteen weeks was the median.)
When looking at breast cancer alone, the analysis found that compared to the control group, the physically active women were less depressed, fatigued and had lower levels of IGF1, an insulin-like hormone linked to increased risk of breast cancer. The physically active women also had signs of overall improved quality of life.
In patients having completed treatment for all types of cancer combined, the analysis found physical activity linked to lower BMI and body weight, (which links to lower cancer risk) along with improvements in physical function and quality of life.
Sources: Fong DY, Ho JW, Hui BP, Lee AM, Macfarlane DJ, Leung SS, Cerin E, Chan WY, Leung IP, Lam SH, Taylor AJ, Cheng KK. "Physical activity for cancer survivors: meta-analysis of randomized controlled trials." BMJ. 2012 Jan 30;344:e70.
Most doctors don't broach the issue of weight loss with their patients, but whether they do may depend upon the doctor's weight – not the patient's, suggests a new survey that was published in the journal Obesity.
The study drew data from an online survey completed by a cross-section of 498 primary care U.S. physicians. The survey showed physicians images of five body sizes, ranging from normal to morbidly obese, asking which image they typically initiate a weight loss conversation.
The study researchers found that practitioners at a normal BMI were only likely to discuss weight loss with their obese patients 30 percent of the time. Practitioners at an overweight or obese BMI were likely to bring up weight loss even less: 18 percent. And physicians with a normal BMI had greater confidence in their ability to provide diet and exercise counseling to their obese patients. When obese patients weighed the same or more than their physician, the doctors were only about ten percent likely to record an obesity diagnosis or initiate a talk about weight loss. They were 90 percent likely to talk weight loss and diagnose obesity when doctors perceived their patients weighed less than they did.
Source: Sara N.Bleich, Wendy L. Bennett, Kimberly A.Gudzune and Lisa A.Cooper. "Impact of Physician BMI on Obesity Care and Beliefs." Obesity (2012); doi:10.1038/oby.2011.402
The research showing that alcohol increases the risk of colorectal cancer is clear. But now a large new study suggests that people who have a family history of colorectal cancer may be especially susceptible to the effects of alcohol increasing their risk of the cancer. The study was published last month online in the American Journal of Clinical Nutrition.
In the study, researchers looked at alcohol consumption patterns among approximately 135,000 men and women, starting in 1980 (for the women) and 1986 (for the men). Participants regularly answered questionnaires about how much alcohol they drank and reported whether they had been diagnosed with colon cancer.
After following the participants through 2006, the study first looked at the whole population. It found that those who drank the most alcohol – over 30 grams of alcohol per day on average, which is about 2 drinks – had an increased risk of colon cancer when compared to those who didn't drink any alcohol.
Yet the link was most pronounced among the drinkers with a parent and/or sibling who had colorectal cancer. Among people with a family history of colorectal cancer, those who drank over 30 grams of alcohol daily had slightly over double the risk of colon cancer – 100 percent more – compared to the nondrinkers. Among those with no family history of colorectal cancer, the risk of drinking over 30 grams of alcohol daily was linked to a 23 percent higher risk of the cancer compared to the nondrinkers.
Source: Alcohol consumption and the risk of colon cancer by family history of colorectal cancer Am J Clin Nutr 2012 95: 2 413-419; First published online January 4, 2012.