Popular herbal supplement hinders the growth of pancreatic cancer cells
A new study from the University of Pittsburgh Cancer Institute suggests that a commonly used herbal supplement, triphala, has cancer-fighting properties that prevent or slow the growth of pancreatic cancer tumors implanted in mice. The study found that an extract of triphala, the dried and powdered fruits of three plants, caused pancreatic cancer cells to die through a process called apoptosis – the body’s normal method of disposing of damaged, unwanted or unneeded cells. This process often is faulty in cancer cells. Results of the study, abstract number LB-142, are being presented in a late-breaking session at the annual meeting of the American Association for Cancer Research, April 14-18, at the Los Angeles Convention Center.
Triphala, one of the most popular herbal preparations in the world, is used for the treatment of intestinal-related disorders. It is typically taken with water and thought to promote appetite and digestion and to increase the number of red blood cells.
"We discovered that triphala fed orally to mice with human pancreatic tumors was an extremely effective inhibitor of the cancer process, inducing apoptosis in cancer cells," said Sanjay K. Srivastava, Ph.D., lead investigator and assistant professor, department of pharmacology, University of Pittsburgh School of Medicine. "Triphala triggered the cancerous cells to die off and significantly reduced the size of the tumors without causing any toxic side effects."
Dr. Srivastava and colleagues fed mice grafted with human pancreatic tumors 1 to 2 milligrams of triphala for five days a week and then compared tumor size and levels of apoptotic proteins in the tumors to a control group of mice that received normal saline only. They found that the mice that received triphala had increased levels of proteins associated with apoptosis and significantly smaller tumor sizes when compared to the control group. Triphala-treated tumors were half the size of tumors in untreated mice. Further testing revealed that triphala activated tumor-suppressor genes, resulting in the generation of proteins that support apoptosis, but did not negatively affect normal pancreatic cells.
"Our results demonstrate that triphala has strong anticancer properties given its ability to induce apoptosis in pancreatic cancer cells without damaging normal pancreatic cells," said Dr. Srivastava. "With follow-up studies, we hope to demonstrate its potential use as a novel agent for the prevention and treatment of pancreatic cancer," said Dr. Srivastava.
Tuesday, April 17, 2007
Cruciferous vegetables give cancer-fighting help
Nutrients in certain vegetables may provide cancer-fighting benefit
Chemicals in cruciferous vegetables, such as broccoli, watercress, cabbage and cauliflower, appear to not only stop human prostate cancer cells from growing in mice but also may cut off the formation of blood vessels that "feed" tumors, says a University of Pittsburgh Cancer Institute study.
"The contribution of diet and nutrition to cancer risk, prevention and treatment has been a major focus of research in recent years because certain nutrients in vegetables and dietary agents appear to protect the body against diseases such as cancer," said Shivendra Singh, Ph.D., lead investigator and professor of pharmacology and urology at the University of Pittsburgh School of Medicine. "From epidemiologic data, we know that increased consumption of vegetables reduces the risk for certain types of cancer, but now we are beginning to understand the mechanisms by which certain vegetables like broccoli may help our bodies fight cancer and other diseases."
Dr. Singh’s study is based on phytochemicals, called isothiocyanates (ITCs), found in several cruciferous vegetables and generated when vegetables are either cut or chewed. His laboratory has found that phenethyl-ITC, or PEITC, is highly effective in suppressing the growth of human prostate cancer cells at concentrations achievable through dietary intake.
The current study follows previous research in which Dr. Singh’s laboratory found that mice grafted with human prostate tumors that received a small amount of PEITC daily for 31 days had significantly reduced tumor size when compared to a control group of mice. Now the researchers have shown that treating cells in culture with PEITC inhibits angiogenesis, a process that plays an important role in the growth and spread of cancer by forming new blood vessels that pass oxygen and nutrients to tumor cells.
"Angiogenesis is a major issue in cancer metastases," said Dr. Singh. "Our results provide promising preliminary evidence that constituents of many edible cruciferous vegetables may slow down, or even halt, this process."
Chemicals in cruciferous vegetables, such as broccoli, watercress, cabbage and cauliflower, appear to not only stop human prostate cancer cells from growing in mice but also may cut off the formation of blood vessels that "feed" tumors, says a University of Pittsburgh Cancer Institute study.
"The contribution of diet and nutrition to cancer risk, prevention and treatment has been a major focus of research in recent years because certain nutrients in vegetables and dietary agents appear to protect the body against diseases such as cancer," said Shivendra Singh, Ph.D., lead investigator and professor of pharmacology and urology at the University of Pittsburgh School of Medicine. "From epidemiologic data, we know that increased consumption of vegetables reduces the risk for certain types of cancer, but now we are beginning to understand the mechanisms by which certain vegetables like broccoli may help our bodies fight cancer and other diseases."
Dr. Singh’s study is based on phytochemicals, called isothiocyanates (ITCs), found in several cruciferous vegetables and generated when vegetables are either cut or chewed. His laboratory has found that phenethyl-ITC, or PEITC, is highly effective in suppressing the growth of human prostate cancer cells at concentrations achievable through dietary intake.
The current study follows previous research in which Dr. Singh’s laboratory found that mice grafted with human prostate tumors that received a small amount of PEITC daily for 31 days had significantly reduced tumor size when compared to a control group of mice. Now the researchers have shown that treating cells in culture with PEITC inhibits angiogenesis, a process that plays an important role in the growth and spread of cancer by forming new blood vessels that pass oxygen and nutrients to tumor cells.
"Angiogenesis is a major issue in cancer metastases," said Dr. Singh. "Our results provide promising preliminary evidence that constituents of many edible cruciferous vegetables may slow down, or even halt, this process."
Monday, April 16, 2007
Fruit and vegetable intake and head and neck cancer
Fruit and vegetable intake and head and neck cancer in a large United States prospective cohort study: Abstract 849
A new study among AARP members shows that just one additional serving of fruit and vegetables per day may lower your risk of head and neck cancer, but the data suggest that you may not want to stop at just one, according to researchers from the National Cancer Institute.
A large prospective study of 500,000 men and women aged 50 and older has found that those who ate more fruit and vegetables had a reduced risk of head and neck cancer. Head and neck cancer is the sixth leading cause of cancer-related mortality worldwide, resulting in more than 350,000 deaths annually.
"Identifying protective factors for head and neck cancer is particularly important as it has a high mortality rate," said Neal Freedman, Ph.D., cancer prevention fellow at the National Cancer Institute.
At the beginning of the study, participants reported their typical dietary habits on a food frequency questionnaire. Freedman and his colleagues followed participants for five years and recorded all diagnoses of head and neck cancer cases during this time.
In their findings, the researchers report that participants who ate six servings of fruit and vegetables per day per 1000 calories had 29 percent less risk for head and neck cancer than did participants who consumed one and a half servings per 1000 calories per day. Typically, adults consume approximately 2000 calories per day. One serving equals approximately one medium sized fresh fruit, one half cup of cut fruit, six ounces fruit juice, one cup leafy vegetables, or one half cup of other vegetables.
"Increasing consumption by just one serving of fruit or vegetables per 1000 calories per day was associated with a six percent reduction in head and neck cancer risk," Freedman said.
According to Freedman, people who ate a lot of fruit also tended to eat a lot of vegetables, and vice versa. To measure these two types of foods independently, the researchers included both fruit and vegetable intake in the statistical models, a common statistical approach. This allowed them to compare participants with different levels of fruit consumption while holding constant the level of vegetable intake and vice versa. When examining fruit and vegetable intake simultaneously, the protective association with vegetables seemed to be stronger than the association with fruits.
"Although we cannot absolutely rule out a cancer preventive role for other lifestyle factors that go along with eating more fruits and vegetables, our results are consistent with those from previous studies," Freedman said. "Our study suggests that fruit and vegetable consumption may protect against head and neck cancer and adds support to current dietary recommendations to increase fruit and vegetable consumption."
A new study among AARP members shows that just one additional serving of fruit and vegetables per day may lower your risk of head and neck cancer, but the data suggest that you may not want to stop at just one, according to researchers from the National Cancer Institute.
A large prospective study of 500,000 men and women aged 50 and older has found that those who ate more fruit and vegetables had a reduced risk of head and neck cancer. Head and neck cancer is the sixth leading cause of cancer-related mortality worldwide, resulting in more than 350,000 deaths annually.
"Identifying protective factors for head and neck cancer is particularly important as it has a high mortality rate," said Neal Freedman, Ph.D., cancer prevention fellow at the National Cancer Institute.
At the beginning of the study, participants reported their typical dietary habits on a food frequency questionnaire. Freedman and his colleagues followed participants for five years and recorded all diagnoses of head and neck cancer cases during this time.
In their findings, the researchers report that participants who ate six servings of fruit and vegetables per day per 1000 calories had 29 percent less risk for head and neck cancer than did participants who consumed one and a half servings per 1000 calories per day. Typically, adults consume approximately 2000 calories per day. One serving equals approximately one medium sized fresh fruit, one half cup of cut fruit, six ounces fruit juice, one cup leafy vegetables, or one half cup of other vegetables.
"Increasing consumption by just one serving of fruit or vegetables per 1000 calories per day was associated with a six percent reduction in head and neck cancer risk," Freedman said.
According to Freedman, people who ate a lot of fruit also tended to eat a lot of vegetables, and vice versa. To measure these two types of foods independently, the researchers included both fruit and vegetable intake in the statistical models, a common statistical approach. This allowed them to compare participants with different levels of fruit consumption while holding constant the level of vegetable intake and vice versa. When examining fruit and vegetable intake simultaneously, the protective association with vegetables seemed to be stronger than the association with fruits.
"Although we cannot absolutely rule out a cancer preventive role for other lifestyle factors that go along with eating more fruits and vegetables, our results are consistent with those from previous studies," Freedman said. "Our study suggests that fruit and vegetable consumption may protect against head and neck cancer and adds support to current dietary recommendations to increase fruit and vegetable consumption."
Flavonols and pancreatic cancer risk
A study of food consumption in 183,518 residents of California and Hawaii has found that a diet high in flavonols might help reduce pancreatic cancer risk, especially in smokers. These compounds are generally ubiquitous in plant-based foods, but are found in highest concentrations in onions, apples, berries, kale and broccoli.
People who ate the largest amounts of flavonols had a 23 percent reduced risk of developing pancreatic cancer compared to those who ate the least, according to a research team led by Laurence Kolonel, M.D., Ph.D., at the Cancer Research Center of Hawaii.
Smokers gained the most benefit. Those who ate the most flavonols reduced their risk of developing pancreatic cancer by 59 percent, compared to those who ate the least, says the study’s lead author, Ute Nöthlings, DrPH, who conducted the study as a postdoctoral fellow in Hawaii and is now a researcher at the German Institute of Human Nutrition Potsdam-Rehbruecke.
‘The effect was largest in smokers, presumably because they are at increased pancreatic cancer risk already," said Nöthlings. Smoking is the only established risk factor for pancreatic cancer, and "short of stopping tobacco use, it has been difficult to consistently show lifestyle factors that might help protect against this deadly cancer," she says.
As part of a larger research project known as The Multiethnic Cohort Study, Kolonel and Nöthlings followed the participants for an average of eight years after they filled out a comprehensive food questionnaire.
Although Nöthlings says the study has a large statistical power because of the large number of pancreatic cancer cases (529) that occurred in the study population, she says that this one study cannot firmly answer the question of whether flavonols can prevent development of pancreatic cancer. "Further epidemiological studies in other populations and geographic regions are needed to confirm our findings," she said.
The study also is the first to examine prospectively specific classes of flavonols and pancreatic cancer risk.
The researchers looked at consumption of three flavonols: quercetin, which is most abundant in onions and apples; kaempferol, found in spinach and some cabbages; and myricetin, found mostly in red onions and berries.
Of the three individual flavonols, kaempferol was associated with the largest risk reduction (22 percent) across all participants. When the researchers divided intake into quartiles, and then compared highest intake to lowest, all the three classes of flavonols were associated with a significant trend toward reduced pancreatic cancer risk in current smokers, but not in never or former smokers. The interaction with smoking status was statistically significant for total flavonols, quercetin and kaempferol.
The researchers say their study did not examine the biological mechanisms by which these flavonols could exert a protective effect against pancreatic cancer. "But anti-carcinogenic effects of flavonoids in general have been attributed to the ability of these constituents to inhibit cell cycle, cell proliferation and oxidative stress, and to induce detoxification enzymes and apoptosis," Nöthlings said.
People who ate the largest amounts of flavonols had a 23 percent reduced risk of developing pancreatic cancer compared to those who ate the least, according to a research team led by Laurence Kolonel, M.D., Ph.D., at the Cancer Research Center of Hawaii.
Smokers gained the most benefit. Those who ate the most flavonols reduced their risk of developing pancreatic cancer by 59 percent, compared to those who ate the least, says the study’s lead author, Ute Nöthlings, DrPH, who conducted the study as a postdoctoral fellow in Hawaii and is now a researcher at the German Institute of Human Nutrition Potsdam-Rehbruecke.
‘The effect was largest in smokers, presumably because they are at increased pancreatic cancer risk already," said Nöthlings. Smoking is the only established risk factor for pancreatic cancer, and "short of stopping tobacco use, it has been difficult to consistently show lifestyle factors that might help protect against this deadly cancer," she says.
As part of a larger research project known as The Multiethnic Cohort Study, Kolonel and Nöthlings followed the participants for an average of eight years after they filled out a comprehensive food questionnaire.
Although Nöthlings says the study has a large statistical power because of the large number of pancreatic cancer cases (529) that occurred in the study population, she says that this one study cannot firmly answer the question of whether flavonols can prevent development of pancreatic cancer. "Further epidemiological studies in other populations and geographic regions are needed to confirm our findings," she said.
The study also is the first to examine prospectively specific classes of flavonols and pancreatic cancer risk.
The researchers looked at consumption of three flavonols: quercetin, which is most abundant in onions and apples; kaempferol, found in spinach and some cabbages; and myricetin, found mostly in red onions and berries.
Of the three individual flavonols, kaempferol was associated with the largest risk reduction (22 percent) across all participants. When the researchers divided intake into quartiles, and then compared highest intake to lowest, all the three classes of flavonols were associated with a significant trend toward reduced pancreatic cancer risk in current smokers, but not in never or former smokers. The interaction with smoking status was statistically significant for total flavonols, quercetin and kaempferol.
The researchers say their study did not examine the biological mechanisms by which these flavonols could exert a protective effect against pancreatic cancer. "But anti-carcinogenic effects of flavonoids in general have been attributed to the ability of these constituents to inhibit cell cycle, cell proliferation and oxidative stress, and to induce detoxification enzymes and apoptosis," Nöthlings said.
Cruciferous vegies & soy vs breast/ ovarian cancers
We all know that eating fruits, vegetables and soy products provides essential nutrition for a healthy lifestyle, while obesity leads to the opposite. Yet proving the effect of nutrition, or obesity, on cancer is an experimental challenge and a focus for scientists. According to emerging evidence being presented at the 2007 Annual Meeting of the American Association for Cancer Research, eating well might still be one of the more pleasurable ways to prevent cancer and promote good health.
Eating such foods as broccoli and soy are believed to offer some protection against cancer, but how this occurs is not well-understood. Now, in laboratory experiments, researchers at the University of California, Los Angeles, have discovered a biological mechanism whereby two compounds in these foods might lower the invasive and metastatic potential of breast and ovarian cancer cells.
They found that diindolylmethane (DIM), a compound resulting from digestion of cruciferous vegetables, and genistein, a major isoflavone in soy, reduce production of two proteins whose chemotactic attraction to each other is necessary for the spread of breast and ovarian cancers.
When applying purified versions of DIM and genistein to motile cancer cells, the researchers could literally watch these cells come to a near halt. When either compound was applied, migration and invasion were substantially reduced.
"We think these compounds might slow or prevent the metastasis of breast and ovarian cancer, which would greatly increase the effectiveness of current treatments," said Erin Hsu, a graduate student in molecular toxicology. "But we need to test that notion in animals before we can be more definitive."
Both DIM and genistein are already being developed for use as a preventive and a chemotherapy treatment for breast cancer, although more extensive toxicological studies are necessary, the researchers say.
The researchers looked at the potential of DIM and genistein to interfere with the "CXCR4/CXCL12 axis," which is known to play a central role in the metastasis of breast cancer and is also thought to play a role in the development of ovarian cancer. Primary cancer cells express very high levels of the CXCR4 chemokine receptor on the surface of their cells, and the organs to which these cancers metastasize secrete high levels of the CXCL12 chemokine ligand. This attraction stimulates the invasive properties of cancer cells and acts like a homing device, drawing the cancer cells to the organs they metastasize to.
When breast and ovarian cancer cell lines are exposed to purified DIM or genistein, levels of CXCR4 and CXCL12 messenger RNAs and proteins decrease in a dose-dependent manner, compared to untreated cells, according to Hsu.
To assess whether the compounds had any effect on the metastatic potential of the cells, the researchers placed the cells in one end of a compartment and watched how they moved toward CXCL12 at the other end. "The cells degrade the extracellular matrix in the upper compartment in order to move toward CXCL12 in the lower compartment, a system that represents a cell culture model for invasiveness," she said.
But if the cells are treated with either DIM or genistein, movement toward CXCL12 is reduced by at least 80 percent compared to untreated cells, the researchers say.
Hsu says that this same chemotactic attraction is thought to play a role in the development of more than 23 different types of cancer, and, so far, they have found that messenger RNA expression of CXCR4 and CXCL12 is substantially reduced when melanoma and prostate cancer cells are treated with the two compounds.
"We have also tested other phytochemicals and seen similar effects, indicating that this mechanism may mediate protective effects of other vegetable products as well," Hsu said.
The amount of DIM and genistein used in this study is probably comparable to use of a high dose of supplements, and is likely not achievable through consumption of food alone, the researchers say.
The mission of the American Association for Cancer Research is to prevent and cure cancer. Founded in 1907, AACR is the world’s oldest and largest professional organization dedicated to advancing cancer research. The membership includes more than 25,000 basic, translational, and clinical researchers; health care professionals; and cancer survivors and advocates in the United States and more than 70 other countries. AACR marshals the full spectrum of expertise from the cancer community to accelerate progress in the prevention, diagnosis and treatment of cancer through high-quality scientific and educational programs. It funds innovative, meritorious research grants. The AACR Annual Meeting attracts over 17,000 participants who share the latest discoveries and developments in the field. Special Conferences throughout the year present novel data across a wide variety of topics in cancer research, diagnosis and treatment. AACR publishes five major peer-reviewed journals: Cancer Research; Clinical Cancer Research; Molecular Cancer Therapeutics; Molecular Cancer Research; and Cancer Epidemiology, Biomarkers & Prevention. Its most recent publication, CR, is a magazine for cancer survivors, patient advocates, their families, physicians, and scientists. It provides a forum for sharing essential, evidence-based information and perspectives on progress in cancer research, survivorship and advocacy.
Eating such foods as broccoli and soy are believed to offer some protection against cancer, but how this occurs is not well-understood. Now, in laboratory experiments, researchers at the University of California, Los Angeles, have discovered a biological mechanism whereby two compounds in these foods might lower the invasive and metastatic potential of breast and ovarian cancer cells.
They found that diindolylmethane (DIM), a compound resulting from digestion of cruciferous vegetables, and genistein, a major isoflavone in soy, reduce production of two proteins whose chemotactic attraction to each other is necessary for the spread of breast and ovarian cancers.
When applying purified versions of DIM and genistein to motile cancer cells, the researchers could literally watch these cells come to a near halt. When either compound was applied, migration and invasion were substantially reduced.
"We think these compounds might slow or prevent the metastasis of breast and ovarian cancer, which would greatly increase the effectiveness of current treatments," said Erin Hsu, a graduate student in molecular toxicology. "But we need to test that notion in animals before we can be more definitive."
Both DIM and genistein are already being developed for use as a preventive and a chemotherapy treatment for breast cancer, although more extensive toxicological studies are necessary, the researchers say.
The researchers looked at the potential of DIM and genistein to interfere with the "CXCR4/CXCL12 axis," which is known to play a central role in the metastasis of breast cancer and is also thought to play a role in the development of ovarian cancer. Primary cancer cells express very high levels of the CXCR4 chemokine receptor on the surface of their cells, and the organs to which these cancers metastasize secrete high levels of the CXCL12 chemokine ligand. This attraction stimulates the invasive properties of cancer cells and acts like a homing device, drawing the cancer cells to the organs they metastasize to.
When breast and ovarian cancer cell lines are exposed to purified DIM or genistein, levels of CXCR4 and CXCL12 messenger RNAs and proteins decrease in a dose-dependent manner, compared to untreated cells, according to Hsu.
To assess whether the compounds had any effect on the metastatic potential of the cells, the researchers placed the cells in one end of a compartment and watched how they moved toward CXCL12 at the other end. "The cells degrade the extracellular matrix in the upper compartment in order to move toward CXCL12 in the lower compartment, a system that represents a cell culture model for invasiveness," she said.
But if the cells are treated with either DIM or genistein, movement toward CXCL12 is reduced by at least 80 percent compared to untreated cells, the researchers say.
Hsu says that this same chemotactic attraction is thought to play a role in the development of more than 23 different types of cancer, and, so far, they have found that messenger RNA expression of CXCR4 and CXCL12 is substantially reduced when melanoma and prostate cancer cells are treated with the two compounds.
"We have also tested other phytochemicals and seen similar effects, indicating that this mechanism may mediate protective effects of other vegetable products as well," Hsu said.
The amount of DIM and genistein used in this study is probably comparable to use of a high dose of supplements, and is likely not achievable through consumption of food alone, the researchers say.
The mission of the American Association for Cancer Research is to prevent and cure cancer. Founded in 1907, AACR is the world’s oldest and largest professional organization dedicated to advancing cancer research. The membership includes more than 25,000 basic, translational, and clinical researchers; health care professionals; and cancer survivors and advocates in the United States and more than 70 other countries. AACR marshals the full spectrum of expertise from the cancer community to accelerate progress in the prevention, diagnosis and treatment of cancer through high-quality scientific and educational programs. It funds innovative, meritorious research grants. The AACR Annual Meeting attracts over 17,000 participants who share the latest discoveries and developments in the field. Special Conferences throughout the year present novel data across a wide variety of topics in cancer research, diagnosis and treatment. AACR publishes five major peer-reviewed journals: Cancer Research; Clinical Cancer Research; Molecular Cancer Therapeutics; Molecular Cancer Research; and Cancer Epidemiology, Biomarkers & Prevention. Its most recent publication, CR, is a magazine for cancer survivors, patient advocates, their families, physicians, and scientists. It provides a forum for sharing essential, evidence-based information and perspectives on progress in cancer research, survivorship and advocacy.
Eating cured meats frequently can lead to bad health
Eating cured meats frequently can lead to lower lung function and potential COPD
Frequent consumption of cured meats results in lower lung function test scores and increases the odds of developing chronic obstructive pulmonary disease (COPD), according to a large cross-sectional survey of adults in the U.S.
The study results appear in the second issue for April 2007 of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society.
Rui Jiang, M.D., Dr.P.H., of Columbia University Medical Center in New York, and three associates showed that the "odds ratio" for developing COPD among individuals who consumed cured meat products 14 times or more per month was 1.93, as compared with those who did not consume cured meats. An odds ratio greater than 1 implies that the event is more likely to occur within that group.
"Cured meats, such as bacon, sausage, luncheon meats and cured hams, are high in nitrites, which are added to meat products as a preservative, an anti-microbial agent, and a color fixative," said Dr. Jiang. "Nitrates generate reactive nitrogen species that may cause damage to the lungs, producing structural changes resembling emphysema."
Although certain rodent studies suggest that inhalation of nitrogen dioxide may contribute to emphysema, no other human studies to date have examined the relationship between consumption of cured meats and COPD, which is the fourth leading cause of death in the U.S.
In 2004, more than 11 million U.S. adults were estimated to suffer from COPD, which results from chronic bronchitis and emphysema, two inflammatory lung diseases that frequently co-exist and interfere with breathing.
The study cohort consisted of 7,352 individuals who participated in the Third National Health and Nutrition Examination Survey, conducted from 1988 to 1994 by the National Center for Health Statistics. The average age of participants was 64.5 years, and 48 percent were male.
"Individuals who consumed cured meats frequently were more likely to be male, of lower socioeconomic status, to be tobacco users, and were less likely to report physician-diagnosed asthma than individuals who never consumed cured meats," said Dr. Jiang. "Those who consumed cured meats more frequently had lower intakes of vitamin C, beta-carotene, fish, fruits, vegetables, and vitamin or mineral supplements. They also had higher intakes of vitamin E and total energy."
The hazard ratio from cured meats associated with lower lung function test results and increased odds for COPD did not change after researchers made adjustments for multiple dietary and other risk factors.
"Adjustment for these factors in our analyses did not appreciably change our findings, suggesting that the observed association between cured meats and lung function was unlikely to be explained by potential dietary confounding factors reported in previous studies," said Dr. Jiang.
The researchers noted that high dietary nitrite intake warrants further evaluation in prospective longitudinal studies as a novel risk factor for COPD.
Frequent consumption of cured meats results in lower lung function test scores and increases the odds of developing chronic obstructive pulmonary disease (COPD), according to a large cross-sectional survey of adults in the U.S.
The study results appear in the second issue for April 2007 of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society.
Rui Jiang, M.D., Dr.P.H., of Columbia University Medical Center in New York, and three associates showed that the "odds ratio" for developing COPD among individuals who consumed cured meat products 14 times or more per month was 1.93, as compared with those who did not consume cured meats. An odds ratio greater than 1 implies that the event is more likely to occur within that group.
"Cured meats, such as bacon, sausage, luncheon meats and cured hams, are high in nitrites, which are added to meat products as a preservative, an anti-microbial agent, and a color fixative," said Dr. Jiang. "Nitrates generate reactive nitrogen species that may cause damage to the lungs, producing structural changes resembling emphysema."
Although certain rodent studies suggest that inhalation of nitrogen dioxide may contribute to emphysema, no other human studies to date have examined the relationship between consumption of cured meats and COPD, which is the fourth leading cause of death in the U.S.
In 2004, more than 11 million U.S. adults were estimated to suffer from COPD, which results from chronic bronchitis and emphysema, two inflammatory lung diseases that frequently co-exist and interfere with breathing.
The study cohort consisted of 7,352 individuals who participated in the Third National Health and Nutrition Examination Survey, conducted from 1988 to 1994 by the National Center for Health Statistics. The average age of participants was 64.5 years, and 48 percent were male.
"Individuals who consumed cured meats frequently were more likely to be male, of lower socioeconomic status, to be tobacco users, and were less likely to report physician-diagnosed asthma than individuals who never consumed cured meats," said Dr. Jiang. "Those who consumed cured meats more frequently had lower intakes of vitamin C, beta-carotene, fish, fruits, vegetables, and vitamin or mineral supplements. They also had higher intakes of vitamin E and total energy."
The hazard ratio from cured meats associated with lower lung function test results and increased odds for COPD did not change after researchers made adjustments for multiple dietary and other risk factors.
"Adjustment for these factors in our analyses did not appreciably change our findings, suggesting that the observed association between cured meats and lung function was unlikely to be explained by potential dietary confounding factors reported in previous studies," said Dr. Jiang.
The researchers noted that high dietary nitrite intake warrants further evaluation in prospective longitudinal studies as a novel risk factor for COPD.
Breastfeeding reduces risk of breast cancer
Breastfeeding reduces risk of breast cancer for women who delay childbirth
Study presented at AACR meeting suggests that breastfeeding has protective benefit for both receptor positive and negative tumors
Breastfeeding can offset the increased risk of invasive breast cancer for women who had their first full-term pregnancy after the age of 25, a study led by researchers at the University of Southern California (USC) suggests.
The findings of the study were presented at a news conference on Monday, April 16 at the 2007 annual meeting of the American Association for Cancer Research held in Los Angeles.
"Breastfeeding may have a protective effect that negates the increased risk of breast cancer associated with late pregnancies," says Giske Ursin, M.D., Ph.D, associate professor of preventive medicine at the Keck School of Medicine of the University of Southern California. "As more women may choose to delay pregnancy until after 25, it is important to note that breastfeeding provides protection against both estrogen and progesterone receptor positive and negative tumors."
While having a first full-term pregnancy before the age of 25 and having many children protect against the type of breast cancers that express estrogen and progesterone receptors, these factors do not protect against the rarer tumors that do not have these receptors. Breastfeeding, however, appears to protect against both types of breast tumors, Ursin says.
Researchers analyzed data for women aged 55 and older—including 995 invasive breast cancer patients–who participated in the Women's Contraceptive and Reproductive Experiences (CARE) Study. The women varied by their age at first birth, their breastfeeding history and hormone receptor status.
Previous results from the Women's CARE Study have shown that early age at first pregnancy (younger than 25) and having many children (defined as four or more) are associated with a lower risk of breast cancer, Ursin says. Researchers sought to gain a better understanding of the associations between reproductive factors and breast cancer risk in women with a late age at first birth, she says.
Breastfeeding appears to have a protective effect regardless of when women started giving birth, Ursin says. This is important since having many children was only protective among women who gave birth early, she says. Giving birth after age 25—the average age that women in the U.S. first give birth, according to Census data—was associated with increased risk of hormone receptor negative breast cancer.
"Evidence suggests that women who have children after age 25 can reduce their risk of breast cancer by choosing to breastfeed," Ursin says.
Study presented at AACR meeting suggests that breastfeeding has protective benefit for both receptor positive and negative tumors
Breastfeeding can offset the increased risk of invasive breast cancer for women who had their first full-term pregnancy after the age of 25, a study led by researchers at the University of Southern California (USC) suggests.
The findings of the study were presented at a news conference on Monday, April 16 at the 2007 annual meeting of the American Association for Cancer Research held in Los Angeles.
"Breastfeeding may have a protective effect that negates the increased risk of breast cancer associated with late pregnancies," says Giske Ursin, M.D., Ph.D, associate professor of preventive medicine at the Keck School of Medicine of the University of Southern California. "As more women may choose to delay pregnancy until after 25, it is important to note that breastfeeding provides protection against both estrogen and progesterone receptor positive and negative tumors."
While having a first full-term pregnancy before the age of 25 and having many children protect against the type of breast cancers that express estrogen and progesterone receptors, these factors do not protect against the rarer tumors that do not have these receptors. Breastfeeding, however, appears to protect against both types of breast tumors, Ursin says.
Researchers analyzed data for women aged 55 and older—including 995 invasive breast cancer patients–who participated in the Women's Contraceptive and Reproductive Experiences (CARE) Study. The women varied by their age at first birth, their breastfeeding history and hormone receptor status.
Previous results from the Women's CARE Study have shown that early age at first pregnancy (younger than 25) and having many children (defined as four or more) are associated with a lower risk of breast cancer, Ursin says. Researchers sought to gain a better understanding of the associations between reproductive factors and breast cancer risk in women with a late age at first birth, she says.
Breastfeeding appears to have a protective effect regardless of when women started giving birth, Ursin says. This is important since having many children was only protective among women who gave birth early, she says. Giving birth after age 25—the average age that women in the U.S. first give birth, according to Census data—was associated with increased risk of hormone receptor negative breast cancer.
"Evidence suggests that women who have children after age 25 can reduce their risk of breast cancer by choosing to breastfeed," Ursin says.
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