For Immediate Release: November 4, 2011
Contact: Mya Nelson, firstname.lastname@example.org, 202-328-7744 x3047
Highlights from the 2011 AICR Research Conference
Links jump to sections:
- Omega 3s and Fiber Together for Colon Cancer Prevention
- Tomato Juice May Reduce Damaging Side Effects of Treatment for Prostate Cancer Patients
- Flaxseed Supplementation Reduces Radiation Therapy-Induced Lung Damage
- Weight Loss Prior to Diagnosis May Reduce Risk of Dying from Prostate Cancer
- Exercise During, And Following, Cancer Treatment May Prevent Heart Disease Years Later
- Vitamin D's Role in Cancer Prevention: New Insights from Basic Laboratory Research
- Heavier Young Adults May Have Increased Cancer Risk Decades Later
November 3, 2011
A series of laboratory studies show how omega-3 fatty acids and fiber act synergistically to reduce the risk of colon cancer.
Healthy fats in fish and high amounts of dietary fiber are two elements of an overall cancer-preventive diet, yet studies have produced conflicting evidence on whether or not these two components have direct effects on cancer risk. A series of recent experimental findings now provides new evidence that the two nutrients act in synergy to reduce the risk of colon cancer.
The research was highlighted today during the AICR Annual Research Conference in Washington, DC.
"Across cell and human studies, the research has shown a degree of uncertainty on whether dietary fiber and omega-3 fatty acids independently have beneficial effects in terms of colon cancer," said Robert S. Chapkin, Regents Professor at Texas A&M University and the lead researcher. "What we are seeing in our studies may explain why.
"When we put both fiber and omega-3 fatty acids together, there's a true synergism that we don't see with either one alone. Together, it invokes novel mechanisms involved in protecting against colon cancer."
Chapkin and his colleagues, including co-presenter Joanne R. Lupton, have conducted a series of cell and animal studies on omega-3 fatty acids and the compound butyrate, a byproduct of dietary fiber fermentation. The researchers were attempting to understand their previous animal studies which consistently showed that when the omega 3-fatty acid called docosahexaenoic acid (DHA) was combined with fermentable fiber (e.g., pectins) the number of colon tumors was reduced far more than either component could reduce tumors by itself. Foods high in long-chain omega-3 fatty acids include cold-water fish; foods high in fermentable fiber include oat bran, apple and citrus fruits.
One study revealed that dietary fat and fiber together appear to drive a molecular mechanism involving mitochondria that tells the cell to die; it increased programmed cell death (apoptosis) to pre-cancerous and colon cancer cells.
Another study found a fish-oil-plus-fermentable-fiber diet led to extensive changes in non-coding RNA (microRNAs), a relative to DNA that can turn genes 'on' and 'off.' This study also showed that the diet affected genes involved with regulating intestinal stem cells.
"Undifferentiated stem cells can become corrupted and are more prone to cancer," said Chapkin. "We found that the protective diet was suppressing genes that keep cells in an undifferentiated state."
Now that animal studies have shown how the combination of dietary fiber and fish oil synergistically work at the molecular level, Chapkin says, the next step is to examine their combined effects in humans. "Collectively, these novel observations emphasize the need to examine both the fat and fiber composition of diets. The failure to address a molecular interaction between fat and fiber may explain why the chemoprotective effects of fish oil and fiber are obscured in some population studies," said Chapkin.
Kolar S, Barhoumi R, Jones CK, Wesley J, Lupton JR, Fan YY, Chapkin RS. "Interactive effects of fatty acid and butyrate-induced mitochondrial Ca(2+) loading and apoptosis in colonocytes." Cancer. 11 May 2011.
Cho Y, Kim H, Turner ND, Mann JC, Wei J, Taddeo SS, Davidson LA, Wang N, Vannucci M, Carroll RJ, Chapkin RS, Lupton JR. "A chemoprotective fish oil- and pectin-containing diet temporally alters gene expression profiles in exfoliated rat colonocytes throughout oncogenesis." J Nutr. 1 Jun 2011.
Shah MS, Schwartz SL, Zhao C, Davidson LA, Zhou B, Lupton JR, Ivanov I, Chapkin RS. "Integrated microRNA and mRNA expression profiling in a rat colon carcinogenesis model: effect of a chemo-protective diet." Physiol Genomics. 1 May 2011.
November 3, 2011
Preliminary study hints at daily glass of tomato juice during treatment providing protection from damaging radiation.
Tomato juice reduces damaging inflammation in patients undergoing radiation therapy for prostate cancer, according to a new study presented today during the poster sessions at the 2011 AICR Annual Research Conference.
The study was one of approximately 120 poster presentations featured at the AICR Research Conference.
AICR's expert report and its updates have found that foods containing lycopene reduce the risk of prostate cancer. Lycopene is an antioxidant compound found in tomatoes, tomato products, and other red fruits such as watermelon and red guavas.
The authors of the study wanted to see what effects lycopene might have on reducing the harmful side effects of radiation therapy for prostate cancer.
The study involved 17 patients undergoing radiation treatment for prostate cancer. Twelve of the patients consumed from 4 to 12 ounces of tomato juice daily throughout their treatment. The duration of treatments ranged from 5 to 8 weeks.
At the end of treatment, participants who drank the tomato juice had decreased levels of several markers of inflammation, including C-reactive protein and interleukin-6, when compared to the five patients who did not drink tomato juice.
This is a small study and the findings would need to be replicated, notes the study's lead author Mridul Datta, PhD, MS, RD, Post-doctoral Fellow at Wake Forest Baptist Medical Center.
"Due to the small number of patients in the intervention groups, we could not distinguish between the benefits of consuming different amounts of tomato juice," Datta noted.
Tomato juice has many compounds in it well studied for its protection against inflammation. It's possible these compounds worked together to protect against damaging inflammation, she said.
"The synergistic effects of whole foods cannot be replicated through supplements," explained Datta. "Rather than giving patients more pills, we wanted to focus on a food-based therapy."
November 3, 2011
Recent AICR-funded animal study demonstrates new role for an ancient grain.
Compounds in flaxseed may protect lung tissue against the common and harmful side effects of radiation therapy, suggests a new study presented today as a poster at the 2011 AICR Annual Research Conference in Washington, DC. The study was published in the online journal BioMed Central Cancer and was supported by AICR.
Approximately one-third of patients experience irreversible lung damage during radiation therapy. According to the study's lead author, Melpo Christofidou-Solomidou, PhD, Professor of Medicine at University of Pennsylvania Medical Center, less than therapeutic doses of radiation are often delivered in order to spare the lungs, thereby compromising treatment.
This study focused on flaxseed's lignans, estrogen-like compounds well studied for their cancer-protective properties. Flaxseeds are also rich in fiber and omega-3 fatty acids.
In the study, mice were fed varying amounts of lignans then exposed to radiation. The group that consumed the highest concentration of lignans experienced the greatest increase in survival and least weight loss, another common side effect of radiation therapy. Key proteins that play a role in cancer protection were increased, as well.
Previous studies by Christofidou-Solomidou found dietary flaxseed protects against lung damage. "This is the first study of its kind to identify that lignan is the component of flaxseed that protects against lung damage," she said.
The amount of lignans the mice consumed was equivalent to approximately one serving of flaxseeds (about 3-4 tablespoons of whole seeds).
These findings are promising but it is too early to make a health claim regarding flaxseed intake, according to Christofidou-Solomidou.
"This study provides compelling data that point to protective components in this small, yet powerful ancient grain, but we still need more research," said Christofidou-Solomidou.
Clinical trials testing the effects of flaxseed on radiation therapy are currently underway.
Christofidou-Solomidou M, Tyagi S, Tan KS, Hagan S, Pietrofesa R, Dukes F, Arguiri E, Heitjan DF, Solomides CC, Cengel KA. "Dietary flaxseed administered post thoracic radiation treatment improves survival and mitigates radiation-induced pneumonopathy in mice." BMC Cancer. 24 June 2011.
November 3, 2011
New AICR-funded study suggests slight weight loss decades before diagnosis may improve prostate cancer prognosis.
Men who lose weight but remain in the healthy weight range years before a prostate cancer diagnosis may lower their risk of death from the cancer, suggests a new AICR-supported study that was highlighted today at the 2011 AICR Annual Research Conference in Washington, DC.
The study was one of the approximately 120 poster presentations featured at the AICR Research Conference.
"There has been some evidence that early and mid-life risk factors may influence prostate cancer incidence and survival," said Julie Kasperzyk, ScD, Research Fellow at the Harvard School of Public Health and the study's lead author. "In this study, we see that weight loss before a prostate cancer diagnosis may be associated with improved outcomes… even among men who fall into the healthy weight category."
The study involved 521 Swedish men diagnosed with prostate cancer between 1989-1994. At diagnosis, participants reported their height and weight, as well as their weight 2 and 20 years before diagnosis. PSA screening was not routine in this population.
After a median 6.5 years of follow-up, men who had lost more than 2 kilograms (4.4 pounds) in the two years before diagnosis had a 59 percent increased risk of dying from the disease during the course of the study. This is likely a consequence of undiagnosed disease, said Kasperzyk.
Yet when weight change during the two years prior to diagnosis was excluded, there was a reverse association that was unexpected.
"Our study found that men who had lost more than 2 kg had a 42 percent reduced risk of prostate cancer specific mortality… This is a provocative finding but we need biological data to back this up and tease out the mechanisms," Kasperzyk said.
Approximately half of the men started at a healthy BMI and most remained at a healthy BMI two years before diagnosis, suggesting that many men stayed within the healthy weight range during the 18-year range.
Research has shown that weight may influence insulin, andrgen and growth hormone signaling, all factors that are implicated to play a role in prostate tumor development.
"This study suggests there are some favorable changes going on with men who lost weight where the tumors are less aggressive… the metabolic milieu during the time of tumor initiation and growth could prime the tumor to be less aggressive.
"We're just really now touching the tip of the iceberg with metabolic processes and prostate cancer," said Kasperzyk.
November 4, 2011
Cancer survivors, especially those diagnosed with early-stage prostate and breast cancer, are at heightened risk of cardiovascular disease years following their diagnosis. The condition is caused by chemotherapy and other cancer therapies that can damage the cardiovascular system.
Recent research, highlighted today during a presentation at the 2011 AICR Annual Research Conference in Washington, DC, suggests that cancer patients who participate in a structured exercise program during chemotherapy (a practice commonly prescribed to heart patients) may reduce the harmful effects of chemotherapy on the cardiovascular system, and therefore may reduce the risk of cardiovascular disease, years after treatment.
"We are starting to learn that individuals that have completed treatments for early-stage cancers years earlier may be at higher risk of dying from cardiovascular disease than cancer, and moreover, may be at higher risk of cardiovascular disease compared with persons who have not had a history of cancer," said Lee W. Jones, PhD, Scientific Director of the Duke Center for Cancer Survivorship at Duke Cancer Institute and a leading researcher in exercise and cancer survivorship.
Cancer therapies can damage survivors' lungs, heart, blood vessels and muscles.
"Exercise rehabilitation following a diagnosis of cancer has, until recently, received scant attention, yet fitness is among one of the strongest indicators of cardiovascular health."
Research now concludes that structured exercise for cancer patients is safe and linked to improvements in cancer-related side effects and quality of life.
Research in the field, presented by Jones, shows that the benefits of exercise in cancer survivors may extend beyond improving treatment side effects and quality of life. For example, several recent observational studies show that increased exercise levels are associated with decreased risk of dying from cancer and other causes following a cancer diagnosis. The reduction in risk of dying of cancer with regular exercise (in cancer survivors) ranged between 18 percent to 67 percent for mortality from any cause.
The findings on exercise extending cancer survivors' lifespan are promising, but they still need to be confirmed in randomized trials, explained Jones. Those studies are coming.
In the presentation, Jones discussed findings from a new study he led that found fitness levels declined almost 10 percent among women undergoing chemotherapy. This study randomly allocated 20 breast cancer patients into either an exercise or non-exercise group. The exercisers biked three times weekly in supervised sessions. After 12 weeks, the fitness levels of the women who did not exercise declined almost 10 percent. But fitness levels among the exercise group improved by 12 percent.
"Our data suggests that women with breast cancer shouldn't wait to exercise after the completion of therapy (as many are inclined to do), but that an exercise training program during treatment, if possible, may prevent the [cardiovascular] 'hit' before it happens," said Jones.
Jones recommends that cancer patients who are not currently exercising regularly should try to perform endurance exercise training (e.g., walking, cycling) at least 3 times a week at between an easy and moderate intensity, for at least 20 minutes per session. Those persons who are currently exercising 3 times a week, should strive to exercise 5 or more days a week but should vary both the duration and intensity of the exercise sessions to encompass both longer duration but easier intensity sessions mixed with shorter sessions of higher intensity.
Jones suggests that cancer patients should talk with their health professional about an exercise program.
November 4, 2011
A new basic research study provides a deeper understanding of the vitamin D levels needed to protect against prostate cancer.
Research from animal models is providing important new insights into vitamin D's role in cancer prevention. A study has now shown the first direct link between levels of vitamin D found in humans and the molecular underpinnings of prostate cancer.
The research was highlighted today during the 2011 AICR Annual Research Conference in Washington, DC.
People obtain vitamin D from sun, food, or supplements. Human studies have long found a link between biomarkers of higher vitamin D levels and cancer prevention. But human studies look at a precursor to vitamin D, explained James C. Fleet, PhD, Professor of Foods and Nutrition at Purdue University and the session presenter.
In the body, the pre-hormone form (called 25OHD) is converted into the active form of vitamin D, 1,25(OH)2D, and this conversion is tightly controlled. Cell studies were finding mechanisms in which this active form of vitamin D suppressed the development of cancer.
"What was missing in the population research was anything showing a direct effect that the levels of the inactive precursor form (25OHD) seen in the blood might have on cells and cancer development," said Fleet. "For that, you have to go to animal models."
In a new animal study, published in Cancer Prevention Research, Fleet and his group have shown how adequate vitamin D levels affect biological processes that protect against prostate cancer. The study is unique in that it uses dietary vitamin D to make blood 25OHD levels comparable to human levels.
Mice predisposed to prostate cancer were broken into one of three dietary groups: consuming low, medium or high amounts of vitamin D. The diet vitamin D levels led to blood 25OHD levels of 26, 78, and 237 nmol/L, respectively. Levels just below 30 nmol/l are seen in approximately 5 percent of White people and 30 percent of African Americans.
"We found that the animals with the lowest levels of vitamin D had biomarkers that suggested they would be more prone to cancer. The really high levels of vitamin D offered no benefit or harm to the animal – for either cancer or bones," said Fleet.
Low vitamin D levels increased cell proliferation and decreased programmed cell death (apoptosis). This diet also increased the severity of prostate lesions that are early indicators of prostate cancer.
In current research, Fleet is working to pinpoint how varying levels of vitamin D affect prostate and colon biology by regulating inflammation. He is also conducting research on how lifelong exposure to low or high vitamin D levels may reduce the risk of cancer.
The studies have implications for vitamin D recommendations, said Fleet. "These animal studies are putting into place a clear picture of the relationship between vitamin D and cancer… is the goal to prevent people from having vitamin D levels that are too low or is it to get people to go higher? These are important differences."
Kovalenko PL, Zhang Z, Yu JG, Li Y, Clinton SK, Fleet JC. "Dietary vitamin d and vitamin d receptor level modulate epithelial cell proliferation and apoptosis in the prostate." Cancer Prev Res.4 Oct 2011.
November 4, 2011
New study links higher BMI at age 25 to increased risk of six obesity-related cancers.
Heavier young adults may have increased risk of cancer later in life, independent of weight change, suggests a new study highlighted today at the 2011 AICR Annual Research Conference in Washington, DC.
The study was one of the approximately 120 poster presentations featured at the AICR Annual Research Conference.
"Cancer is a chronic disease with a long latent period and our study and others show that it is plausible early adulthood might represent a critical window of exposure that affects cancer risk later in life," said the study's lead author Xuesong Han, Research Assistant Professor at University of North Carolina Chapel Hill and an AICR Marilyn Gentry Fellow.
Research shows that overweight and obesity are linked to increased risk of many common types of cancer. Han and her colleagues focused on six types of obesity-related cancer: postmenopausal breast, endometrial, colorectal, kidney, pancreatic and esophageal.
The study used data from 13,901 participants of the Atherosclerosis Risk in Communities (ARIC) study. The study began in 1987-1989 when participants were ages 45 to 64. At that time, participants reported their weight at age 25 and had their weight and height measured. Cancer incidence was tracked through 2006.
Every 5 kg/m2 increase in BMI at age 25 linked to a 9 percent greater risk of the six obesity-related cancers combined. For example, a person with a BMI of 30 would have a 9 percent greater increase in risk than someone with a BMI of 25. A BMI increase of 5 kg/m2 is equivalent to a 5'4" woman gaining approximately 30 pounds.
Those obese at age 25 had 3.4 times the risk of endometrial cancer and 4.7 times the risk of esophageal cancer compared to those who were normal weight.
The risk remained after adjusting for weight change during adulthood.
Excess body fat may increase levels of estrogen and insulin, and lead to inflammation says Han. "Early adulthood may also present a risk accumulation from childhood and adolescence, and unhealthy behaviors of early adulthood may continue over time."
"This study suggests that excess weight during young adulthood should be avoided because it might contribute to increases in cancer risk that might be independent of weight change later in life."
The American Institute for Cancer Research (AICR) is the cancer charity that fosters research on the relationship of nutrition, physical activity and weight management to cancer risk, interprets the scientific literature and educates the public about the results. It has contributed more than $95 million for innovative research conducted at universities, hospitals and research centers across the country. AICR has published two landmark reports that interpret the accumulated research in the field, and is committed to a process of continuous review. AICR also provides a wide range of educational programs to help millions of Americans learn to make dietary changes for lower cancer risk. Its award-winning New American Plate program is presented in brochures, seminars and on its website, www.aicr.org. AICR is a member of the World Cancer Research Fund International.