Can a drop of water cause sunburn?
To the gardening world it may have always been considered a fact, but science has never proved the widely held belief that watering your garden in the midday sun can lead to burnt plants. Now a study into sunlit water droplets, published in New Phytologist, provides an answer that not only reverberates across gardens and allotments, but may have implications for forest fires and human sunburn.
"The problem of light focusing by water droplets adhered to plants has never been thoroughly investigated, neither theoretically, nor experimentally", said lead researcher Dr Gabor Horvath, from Hungary's Eotvos University. "However, this is far from a trivial question. The prevailing opinion is that forest fires can be sparked by intense sunlight focused by water drops on dried-out vegetation."
The team conducted both computational and experimental studies to determine how the contact angle between the water droplet and a leaf affects the light environment on a leaf blade. The aim was to clarify the environmental conditions under which sunlit water drops can cause leaf burn.
These experiments found that water droplets on a smooth surface, such as maple or ginkgo leaves, cannot cause leaf burn. However in contrast the team found that floating fern leaves, which have small wax hairs, are susceptible to leaf burn. This is because the hairs can hold the water droplets in focus above the leaf's surface, acting as a magnifying glass. The latter not only partly confirms the widely held belief of gardeners, but also opens an analogous issue of sunburn on hairy human skin after bathing.
"In sunshine water drops residing on smooth hairless plant leaves are unlikely to damage the leaf tissue", summarised Horvath and co-authors. "However water drops held by plant hairs can indeed cause sunburn and the same phenomenon can occur when water droplets are held above human skin by body hair."
Monday, January 11, 2010
Sedentary TV time may cut life short
Study highlights:
A study found that every hour spent in front of the television per day brings with it an 11 percent greater risk of premature death from all causes, and an 18 percent greater risk of dying from cardiovascular disease.
The findings apply to both obese and overweight people as well as people with a healthy weight because prolonged periods of sitting have an unhealthy influence on blood sugar and blood fat levels.
DALLAS, Jan. 11, 2010 — Couch potatoes beware: every hour of television watched per day may increase the risk of dying earlier from cardiovascular disease, according to research reported in Circulation: Journal of the American Heart Association.
Australian researchers tracked the lifestyle habits of 8,800 adults and found that each hour spent in front of the television daily was associated with:
• an 11 percent increased risk of death from all causes,
• a 9 percent increased risk of cancer death; and
• an 18 percent increased risk of cardiovascular disease (CVD)-related death.
Compared with people who watched less than two hours of television daily, those who watched more than four hours a day had a 46 percent higher risk of death from all causes and an 80 percent increased risk for CVD-related death. This association held regardless of other independent and common cardiovascular disease risk factors, including smoking, high blood pressure, high blood cholesterol, unhealthy diet, excessive waist circumference, and leisure-time exercises.
While the study focused specifically on television watching, the findings suggest that any prolonged sedentary behavior, such as sitting at a desk or in front of a computer, may pose a risk to one’s health. The human body was designed to move, not sit for extended periods of time, said David Dunstan, Ph.D., the study’s lead author and professor and Head of the Physical Activity Laboratory in the Division of Metabolism and Obesity at the Baker IDI Heart and Diabetes Institute in Victoria, Australia.
“What has happened is that a lot of the normal activities of daily living that involved standing up and moving the muscles in the body have been converted to sitting,” Dunstan said. “Technological, social, and economic changes mean that people don’t move their muscles as much as they used to - consequently the levels of energy expenditure as people go about their lives continue to shrink. For many people, on a daily basis they simply shift from one chair to another – from the chair in the car to the chair in the office to the chair in front of the television.”
Dunstan said the findings apply not only to individuals who are overweight and obese, but also those who have a healthy weight. “Even if someone has a healthy body weight, sitting for long periods of time still has an unhealthy influence on their blood sugar and blood fats,” he said.
Although the study was conducted in Australia, Dunstan said the findings are certainly applicable to Americans. Average daily television watching is approximately three hours in Australia and the United Kingdom, and up to eight hours in the United States, where two-thirds of all adults are either overweight or obese.
The benefits of exercise have been long established, but researchers wanted to know what happens when people sit too much. Television-watching is the most common sedentary activity carried out in the home.
Researchers interviewed 3,846 men and 4,954 women age 25 and older who underwent oral glucose-tolerance tests and provided blood samples so researchers could measure biomarkers such as cholesterol and blood sugar levels. Participants were enrolled from 1999–2000 and followed through 2006. They reported their television-viewing habits for the previous seven days and were grouped into one of three categories: those who watched less than two hours per day; those who watched between two and four hours daily; and those who watched more than four hours.
People with a history of CVD were excluded from the study. During the more than six-year follow-up, there were 284 deaths — 87 due to CVD and 125 due to cancer.
The association between cancer and television viewing was only modest, researchers reported. However, there was a direct association between the amount of television watched and elevated CVD death as well as death from all causes even after accounting for typical CVD risk factors and other lifestyle factors. The implications are simple, Dunstan said. “In addition to doing regular exercise, avoid sitting for prolonged periods and keep in mind to ‘move more, more often’. Too much sitting is bad for health.”
A study found that every hour spent in front of the television per day brings with it an 11 percent greater risk of premature death from all causes, and an 18 percent greater risk of dying from cardiovascular disease.
The findings apply to both obese and overweight people as well as people with a healthy weight because prolonged periods of sitting have an unhealthy influence on blood sugar and blood fat levels.
DALLAS, Jan. 11, 2010 — Couch potatoes beware: every hour of television watched per day may increase the risk of dying earlier from cardiovascular disease, according to research reported in Circulation: Journal of the American Heart Association.
Australian researchers tracked the lifestyle habits of 8,800 adults and found that each hour spent in front of the television daily was associated with:
• an 11 percent increased risk of death from all causes,
• a 9 percent increased risk of cancer death; and
• an 18 percent increased risk of cardiovascular disease (CVD)-related death.
Compared with people who watched less than two hours of television daily, those who watched more than four hours a day had a 46 percent higher risk of death from all causes and an 80 percent increased risk for CVD-related death. This association held regardless of other independent and common cardiovascular disease risk factors, including smoking, high blood pressure, high blood cholesterol, unhealthy diet, excessive waist circumference, and leisure-time exercises.
While the study focused specifically on television watching, the findings suggest that any prolonged sedentary behavior, such as sitting at a desk or in front of a computer, may pose a risk to one’s health. The human body was designed to move, not sit for extended periods of time, said David Dunstan, Ph.D., the study’s lead author and professor and Head of the Physical Activity Laboratory in the Division of Metabolism and Obesity at the Baker IDI Heart and Diabetes Institute in Victoria, Australia.
“What has happened is that a lot of the normal activities of daily living that involved standing up and moving the muscles in the body have been converted to sitting,” Dunstan said. “Technological, social, and economic changes mean that people don’t move their muscles as much as they used to - consequently the levels of energy expenditure as people go about their lives continue to shrink. For many people, on a daily basis they simply shift from one chair to another – from the chair in the car to the chair in the office to the chair in front of the television.”
Dunstan said the findings apply not only to individuals who are overweight and obese, but also those who have a healthy weight. “Even if someone has a healthy body weight, sitting for long periods of time still has an unhealthy influence on their blood sugar and blood fats,” he said.
Although the study was conducted in Australia, Dunstan said the findings are certainly applicable to Americans. Average daily television watching is approximately three hours in Australia and the United Kingdom, and up to eight hours in the United States, where two-thirds of all adults are either overweight or obese.
The benefits of exercise have been long established, but researchers wanted to know what happens when people sit too much. Television-watching is the most common sedentary activity carried out in the home.
Researchers interviewed 3,846 men and 4,954 women age 25 and older who underwent oral glucose-tolerance tests and provided blood samples so researchers could measure biomarkers such as cholesterol and blood sugar levels. Participants were enrolled from 1999–2000 and followed through 2006. They reported their television-viewing habits for the previous seven days and were grouped into one of three categories: those who watched less than two hours per day; those who watched between two and four hours daily; and those who watched more than four hours.
People with a history of CVD were excluded from the study. During the more than six-year follow-up, there were 284 deaths — 87 due to CVD and 125 due to cancer.
The association between cancer and television viewing was only modest, researchers reported. However, there was a direct association between the amount of television watched and elevated CVD death as well as death from all causes even after accounting for typical CVD risk factors and other lifestyle factors. The implications are simple, Dunstan said. “In addition to doing regular exercise, avoid sitting for prolonged periods and keep in mind to ‘move more, more often’. Too much sitting is bad for health.”
Exercise = Reduced Cogntive Risk
Exercise associated with preventing, improving mild cognitive impairment
Moderate physical activity performed in midlife or later appears to be associated with a reduced risk of mild cognitive impairment, whereas a six-month high-intensity aerobic exercise program may improve cognitive function in individuals who already have the condition, according to two reports in the January issue of Archives of Neurology, one of the JAMA/Archives journals.
Mild cognitive impairment is an intermediate state between the normal thinking, learning and memory changes that occur with age and dementia, according to background information in one of the articles. Each year, 10 percent to 15 percent of individuals with mild cognitive impairment will develop dementia, as compared with 1 percent to 2 percent of the general population. Previous studies in animals and humans have suggested that exercise may improve cognitive function.
In one article, Laura D. Baker, Ph.D., of the University of Washington School of Medicine and Veterans Affairs Puget Sound Health Care System, Seattle, and colleagues report the results of a randomized, controlled clinical trial involving 33 adults with mild cognitive impairment (17 women, average age 70). A group of 23 were randomly assigned to an aerobic exercise group and exercised at high intensity levels under the supervision of a trainer for 45 to 60 minutes per day, four days per week. The control group of 10 individuals performed supervised stretching exercises according to the same schedule but kept their heart rate low. Fitness testing, body fat analysis, blood tests of metabolic markers and cognitive functions were assessed before, during and after the six-month trial.
A total of 29 participants completed the study. Overall, the patients in the high-intensity aerobic exercise group experienced improved cognitive function compared with those in the control group. These effects were more pronounced in women than in men, despite similar increases in fitness. The sex differences may be related to the metabolic effects of exercise, as changes to the body's use and production of insulin, glucose and the stress hormone cortisol differed in men and women.
"Aerobic exercise is a cost-effective practice that is associated with numerous physical benefits. The results of this study suggest that exercise also provides a cognitive benefit for some adults with mild cognitive impairment," the authors conclude. "Six months of a behavioral intervention involving regular intervals of increased heart rate was sufficient to improve cognitive performance for an at-risk group without the cost and adverse effects associated with most pharmaceutical therapies."
In another report, Yonas E. Geda, M.D., M.Sc., and colleagues at Mayo Clinic, Rochester, Minn., studied 1,324 individuals without dementia who were part of the Mayo Clinic Study of Aging. Participants completed a physical exercise questionnaire between 2006 and 2008. They were then assessed by an expert consensus panel, who classified each as having normal cognition or mild cognitive impairment.
A total of 198 participants (median or midpoint age, 83 years) were determined to have mild cognitive impairment and 1,126 (median age 80) had normal cognition. Those who reported performing moderate exercise—such as brisk walking, aerobics, yoga, strength training or swimming—during midlife or late life were less likely to have mild cognitive impairment. Midlife moderate exercise was associated with 39 percent reduction in the odds of developing the condition, and moderate exercise in late life was associated with a 32 percent reduction. The findings were consistent among men and women.
Light exercise (such as bowling, slow dancing or golfing with a cart) or vigorous exercise (including jogging, skiing and racquetball) were not independently associated with reduced risk for mild cognitive impairment.
Physical exercise may protect against mild cognitive impairment via the production of nerve-protecting compounds, greater blood flow to the brain, improved development and survival of neurons and the decreased risk of heart and blood vessel diseases, the authors note. "A second possibility is that physical exercise may be a marker for a healthy lifestyle," they write. "A subject who engages in regular physical exercise may also show the same type of discipline in dietary habits, accident prevention, adherence to preventive intervention, compliance with medical care and similar health-promoting behaviors."
Future study is needed to confirm whether exercise is associated with the decreased risk of mild cognitive impairment and provide additional information on cause and effect relationships, they conclude.
Moderate physical activity performed in midlife or later appears to be associated with a reduced risk of mild cognitive impairment, whereas a six-month high-intensity aerobic exercise program may improve cognitive function in individuals who already have the condition, according to two reports in the January issue of Archives of Neurology, one of the JAMA/Archives journals.
Mild cognitive impairment is an intermediate state between the normal thinking, learning and memory changes that occur with age and dementia, according to background information in one of the articles. Each year, 10 percent to 15 percent of individuals with mild cognitive impairment will develop dementia, as compared with 1 percent to 2 percent of the general population. Previous studies in animals and humans have suggested that exercise may improve cognitive function.
In one article, Laura D. Baker, Ph.D., of the University of Washington School of Medicine and Veterans Affairs Puget Sound Health Care System, Seattle, and colleagues report the results of a randomized, controlled clinical trial involving 33 adults with mild cognitive impairment (17 women, average age 70). A group of 23 were randomly assigned to an aerobic exercise group and exercised at high intensity levels under the supervision of a trainer for 45 to 60 minutes per day, four days per week. The control group of 10 individuals performed supervised stretching exercises according to the same schedule but kept their heart rate low. Fitness testing, body fat analysis, blood tests of metabolic markers and cognitive functions were assessed before, during and after the six-month trial.
A total of 29 participants completed the study. Overall, the patients in the high-intensity aerobic exercise group experienced improved cognitive function compared with those in the control group. These effects were more pronounced in women than in men, despite similar increases in fitness. The sex differences may be related to the metabolic effects of exercise, as changes to the body's use and production of insulin, glucose and the stress hormone cortisol differed in men and women.
"Aerobic exercise is a cost-effective practice that is associated with numerous physical benefits. The results of this study suggest that exercise also provides a cognitive benefit for some adults with mild cognitive impairment," the authors conclude. "Six months of a behavioral intervention involving regular intervals of increased heart rate was sufficient to improve cognitive performance for an at-risk group without the cost and adverse effects associated with most pharmaceutical therapies."
In another report, Yonas E. Geda, M.D., M.Sc., and colleagues at Mayo Clinic, Rochester, Minn., studied 1,324 individuals without dementia who were part of the Mayo Clinic Study of Aging. Participants completed a physical exercise questionnaire between 2006 and 2008. They were then assessed by an expert consensus panel, who classified each as having normal cognition or mild cognitive impairment.
A total of 198 participants (median or midpoint age, 83 years) were determined to have mild cognitive impairment and 1,126 (median age 80) had normal cognition. Those who reported performing moderate exercise—such as brisk walking, aerobics, yoga, strength training or swimming—during midlife or late life were less likely to have mild cognitive impairment. Midlife moderate exercise was associated with 39 percent reduction in the odds of developing the condition, and moderate exercise in late life was associated with a 32 percent reduction. The findings were consistent among men and women.
Light exercise (such as bowling, slow dancing or golfing with a cart) or vigorous exercise (including jogging, skiing and racquetball) were not independently associated with reduced risk for mild cognitive impairment.
Physical exercise may protect against mild cognitive impairment via the production of nerve-protecting compounds, greater blood flow to the brain, improved development and survival of neurons and the decreased risk of heart and blood vessel diseases, the authors note. "A second possibility is that physical exercise may be a marker for a healthy lifestyle," they write. "A subject who engages in regular physical exercise may also show the same type of discipline in dietary habits, accident prevention, adherence to preventive intervention, compliance with medical care and similar health-promoting behaviors."
Future study is needed to confirm whether exercise is associated with the decreased risk of mild cognitive impairment and provide additional information on cause and effect relationships, they conclude.
YOGA REDUCES INFLAMMATION
YOGA REDUCES CYTOKINE LEVELS KNOWN TO PROMOTE INFLAMMATION
Regularly practicing yoga exercises may lower a number of compounds in the blood and reduce the level of inflammation that normally rises because of both normal aging and stress, a new study has shown.
The study, done by Ohio State University researchers and just reported in the journal Psychosomatic Medicine, showed that women who routinely practiced yoga had lower amounts of the cytokine interleukin-6 (IL-6) in their blood.
The women also showed smaller increases in IL-6 after stressful experiences than did women who were the same age and weight but who were not yoga practitioners.
IL-6 is an important part of the body’s inflammatory response and has been implicated in heart disease, stroke, type-2 diabetes, arthritis and a host of other age-related debilitating diseases. Reducing inflammation may provide substantial short- and long-term health benefits, the researchers suggest.
“In addition to having lower levels of inflammation before they were stressed, we also saw lower inflammatory responses to stress among the expert yoga practitioners in the study,” explained Janice Kiecolt-Glaser, professor of psychiatry and psychology and lead author of the study.
“Hopefully, this means that people can eventually learn to respond less strongly to stressors in their everyday lives by using yoga and other stress-reducing modalities.”
For the study, the researchers assembled a group of 50 women, age 41 on average. They were divided into two groups – “novices,” who had either taken yoga classes or who practiced at home with yoga videos for no more than 6 to 12 sessions, and “experts,” who had practiced yoga one of two times weekly for at least two years and at least twice weekly for the last year.
Each of the women was asked to attend three sessions in the university’s Clinical Research Center at two-week intervals. Each session began with participants filling out questionnaires and completing several psychological tests to gauge mood and anxiety levels.
Each woman also was fitted with a catheter in one arm through which blood samples could be taken several times during the research tasks for later evaluation.
Participants then performed several tasks during each visit designed to increase their stress levels including immersing their foot into extremely cold water for a minute, after which they were asked to solve a series of successively more difficult mathematics problems without paper or pencil.
Following these “stressors,” participants would either participate in a yoga session, walk on treadmill set at a slow pace (.5 miles per hour) designed to mirror the metabolic demands of the yoga session or watch neutral, rather boring videos. The treadmill and video tasks were designed as contrast conditions to the yoga session.
Once the blood samples were analyzed after the study, researchers saw that the women labeled as “novices” had levels of the pro-inflammatory cytokine IL-6 that were 41 percent higher than those in the study’s “experts.”
“In essence, the experts walked into the study with lower levels of inflammation than the novices, and the experts were also better able to limit their stress responses than were the novices,” Kiecolt-Glaser explained.
The researchers did not find the differences they had expected between the novices and experts in their physiological responses to the yoga session.
Co-author Lisa Christian, an assistant professor of psychology, psychiatry and obstetrics and gynecology, suggested one possible reason:
“The yoga poses we used were chosen from those thought to be restorative or relaxing. We had to limit the movements to those novices could perform as well as experts.
“Part of the problem with sorting out exactly what makes yoga effective in reducing stress is that if you try to break it down into its components, like the movements or the breathing, it’s hard to say what particular thing is causing the effect,” said Christian, herself a yoga instructor. “That research simply hasn’t been done yet.”
Ron Glaser, a co-author and a professor of molecular virology, immunology and medical genetics, said that the study has some fairly clear implications for health.
“We know that inflammation plays a major role in many diseases. Yoga appears to be a simple and enjoyable way to add an intervention that might reduce risks for developing heart disease, diabetes and other age-related diseases” he said.
“This is an easy thing people can do to help reduce their risks of illness.”
Bill Malarkey, an professor of internal medicine and co-author on the study, pointed to the inflexibility that routinely comes with aging.
“Muscles shorten and tighten over time, mainly because of inactivity,” he said. “The stretching and exercise that comes with yoga actually increases a person’s flexibility and that, in turn, allows relaxation which can lower stress.”
Malarkey sees the people’s adoption of yoga or other regular exercise as one of the key solutions to our current health care crisis. “People need to be educated about this. They need to be taking responsibility for their health and how they live. Doing yoga and similar activities can make a difference.”
As a clinician, he says, “Much of my time is being spent simply trying to get people to slow down.”
The researchers’ next step is a clinical trial to see if yoga can improve the health and reduce inflammation that has been linked to debilitating fatigue among breast cancer survivors. They’re seeking 200 women to volunteer for the study that’s funded by the National Cancer Institute.
Regularly practicing yoga exercises may lower a number of compounds in the blood and reduce the level of inflammation that normally rises because of both normal aging and stress, a new study has shown.
The study, done by Ohio State University researchers and just reported in the journal Psychosomatic Medicine, showed that women who routinely practiced yoga had lower amounts of the cytokine interleukin-6 (IL-6) in their blood.
The women also showed smaller increases in IL-6 after stressful experiences than did women who were the same age and weight but who were not yoga practitioners.
IL-6 is an important part of the body’s inflammatory response and has been implicated in heart disease, stroke, type-2 diabetes, arthritis and a host of other age-related debilitating diseases. Reducing inflammation may provide substantial short- and long-term health benefits, the researchers suggest.
“In addition to having lower levels of inflammation before they were stressed, we also saw lower inflammatory responses to stress among the expert yoga practitioners in the study,” explained Janice Kiecolt-Glaser, professor of psychiatry and psychology and lead author of the study.
“Hopefully, this means that people can eventually learn to respond less strongly to stressors in their everyday lives by using yoga and other stress-reducing modalities.”
For the study, the researchers assembled a group of 50 women, age 41 on average. They were divided into two groups – “novices,” who had either taken yoga classes or who practiced at home with yoga videos for no more than 6 to 12 sessions, and “experts,” who had practiced yoga one of two times weekly for at least two years and at least twice weekly for the last year.
Each of the women was asked to attend three sessions in the university’s Clinical Research Center at two-week intervals. Each session began with participants filling out questionnaires and completing several psychological tests to gauge mood and anxiety levels.
Each woman also was fitted with a catheter in one arm through which blood samples could be taken several times during the research tasks for later evaluation.
Participants then performed several tasks during each visit designed to increase their stress levels including immersing their foot into extremely cold water for a minute, after which they were asked to solve a series of successively more difficult mathematics problems without paper or pencil.
Following these “stressors,” participants would either participate in a yoga session, walk on treadmill set at a slow pace (.5 miles per hour) designed to mirror the metabolic demands of the yoga session or watch neutral, rather boring videos. The treadmill and video tasks were designed as contrast conditions to the yoga session.
Once the blood samples were analyzed after the study, researchers saw that the women labeled as “novices” had levels of the pro-inflammatory cytokine IL-6 that were 41 percent higher than those in the study’s “experts.”
“In essence, the experts walked into the study with lower levels of inflammation than the novices, and the experts were also better able to limit their stress responses than were the novices,” Kiecolt-Glaser explained.
The researchers did not find the differences they had expected between the novices and experts in their physiological responses to the yoga session.
Co-author Lisa Christian, an assistant professor of psychology, psychiatry and obstetrics and gynecology, suggested one possible reason:
“The yoga poses we used were chosen from those thought to be restorative or relaxing. We had to limit the movements to those novices could perform as well as experts.
“Part of the problem with sorting out exactly what makes yoga effective in reducing stress is that if you try to break it down into its components, like the movements or the breathing, it’s hard to say what particular thing is causing the effect,” said Christian, herself a yoga instructor. “That research simply hasn’t been done yet.”
Ron Glaser, a co-author and a professor of molecular virology, immunology and medical genetics, said that the study has some fairly clear implications for health.
“We know that inflammation plays a major role in many diseases. Yoga appears to be a simple and enjoyable way to add an intervention that might reduce risks for developing heart disease, diabetes and other age-related diseases” he said.
“This is an easy thing people can do to help reduce their risks of illness.”
Bill Malarkey, an professor of internal medicine and co-author on the study, pointed to the inflexibility that routinely comes with aging.
“Muscles shorten and tighten over time, mainly because of inactivity,” he said. “The stretching and exercise that comes with yoga actually increases a person’s flexibility and that, in turn, allows relaxation which can lower stress.”
Malarkey sees the people’s adoption of yoga or other regular exercise as one of the key solutions to our current health care crisis. “People need to be educated about this. They need to be taking responsibility for their health and how they live. Doing yoga and similar activities can make a difference.”
As a clinician, he says, “Much of my time is being spent simply trying to get people to slow down.”
The researchers’ next step is a clinical trial to see if yoga can improve the health and reduce inflammation that has been linked to debilitating fatigue among breast cancer survivors. They’re seeking 200 women to volunteer for the study that’s funded by the National Cancer Institute.
Mango fights colon, and breast cancer
*
Mango. If you know little about this fruit, understand this: It's been found to prevent or stop certain colon and breast cancer cells in the lab.
That's according to a new study by Texas AgriLife Research food scientists, who examined the five varieties most common in the U.S.: Kent, Francine, Ataulfo, Tommy/Atkins and Haden.
Though the mango is an ancient fruit heavily consumed in many parts of the world, little has been known about its health aspects. The National Mango Board commissioned a variety of studies with several U.S. researchers to help determine its nutritional value.
"If you look at what people currently perceive as a superfood, people think of high antioxidant capacity, and mango is not quite there," said Dr. Susanne Talcott, who with her husband, Dr. Steve Talcott, conducted the study on cancer cells. "In comparison with antioxidants in blueberry, acai and pomegranate, it's not even close."
But the team checked mango against cancer cells anyway, and found it prevented or stopped cancer growth in certain breast and colon cell lines, Susanne Talcott noted.
"It has about four to five times less antioxidant capacity than an average wine grape, and it still holds up fairly well in anticancer activity. If you look at it from the physiological and nutritional standpoint, taking everything together, it would be a high-ranking super food," she said. "It would be good to include mangoes as part of the regular diet."
The Talcotts tested mango polyphenol extracts in vitro on colon, breast, lung, leukemia and prostate cancers. Polyphenols are natural substances in plants and are associated with a variety of compounds known to promote good health.
Mango showed some impact on lung, leukemia and prostate cancers but was most effective on the most common breast and colon cancers.
"What we found is that not all cell lines are sensitive to the same extent to an anticancer agent," she said. "But the breast and colon cancer lines underwent apotosis, or programmed cell death. Additionally, we found that when we tested normal colon cells side by side with the colon cancer cells, that the mango polyphenolics did not harm the normal cells."
The duo did further tests on the colon cancer lines because a mango contains both small molecules that are readily absorbed and larger molecules that would not be absorbed and thus remain present in a colon.
"We found the normal cells weren't killed, so mango is not expected to be damaging in the body," she said. "That is a general observation for any natural agent, that they target cancer cells and leave the healthy cells alone, in reasonable concentrations at least."
The Talcotts evaluated polyphenolics, and more specifically gallotannins as being the class of bioactive compounds (responsible for preventing or stopping cancer cells). Tannins are polyphenols that are often bitter or drying and found in such common foods as grape seed, wine and tea.
The study found that the cell cycle, which is the division cells go through, was interrupted. This is crucial information, Suzanne Talcott said, because it indicates a possible mechanism for how the cancer cells are prevented or stopped.
"For cells that may be on the verge of mutating or being damaged, mango polyphenolics prevent this kind of damage," she said.
The Talcotts hope to do a small clinical trial with individuals who have increased inflamation in their intestines with a higher risk for cancer.
"From there, if there is any proven efficacy, then we would do a larger trial to see if there is any clinical relevance," she said.
###
According to the National Mango Board, based in Winter Park, Fla., most mangoes consumed in the U.S. are produced in Mexico, Ecuador, Peru, Brazil, Guatemala and Haiti. Mangoes are native to southeast Asia and India and are produced in tropical climates. They were introduced to the U.S. in the late 1800s, and a few commercial acres still exist in California and Florida.
Mango. If you know little about this fruit, understand this: It's been found to prevent or stop certain colon and breast cancer cells in the lab.
That's according to a new study by Texas AgriLife Research food scientists, who examined the five varieties most common in the U.S.: Kent, Francine, Ataulfo, Tommy/Atkins and Haden.
Though the mango is an ancient fruit heavily consumed in many parts of the world, little has been known about its health aspects. The National Mango Board commissioned a variety of studies with several U.S. researchers to help determine its nutritional value.
"If you look at what people currently perceive as a superfood, people think of high antioxidant capacity, and mango is not quite there," said Dr. Susanne Talcott, who with her husband, Dr. Steve Talcott, conducted the study on cancer cells. "In comparison with antioxidants in blueberry, acai and pomegranate, it's not even close."
But the team checked mango against cancer cells anyway, and found it prevented or stopped cancer growth in certain breast and colon cell lines, Susanne Talcott noted.
"It has about four to five times less antioxidant capacity than an average wine grape, and it still holds up fairly well in anticancer activity. If you look at it from the physiological and nutritional standpoint, taking everything together, it would be a high-ranking super food," she said. "It would be good to include mangoes as part of the regular diet."
The Talcotts tested mango polyphenol extracts in vitro on colon, breast, lung, leukemia and prostate cancers. Polyphenols are natural substances in plants and are associated with a variety of compounds known to promote good health.
Mango showed some impact on lung, leukemia and prostate cancers but was most effective on the most common breast and colon cancers.
"What we found is that not all cell lines are sensitive to the same extent to an anticancer agent," she said. "But the breast and colon cancer lines underwent apotosis, or programmed cell death. Additionally, we found that when we tested normal colon cells side by side with the colon cancer cells, that the mango polyphenolics did not harm the normal cells."
The duo did further tests on the colon cancer lines because a mango contains both small molecules that are readily absorbed and larger molecules that would not be absorbed and thus remain present in a colon.
"We found the normal cells weren't killed, so mango is not expected to be damaging in the body," she said. "That is a general observation for any natural agent, that they target cancer cells and leave the healthy cells alone, in reasonable concentrations at least."
The Talcotts evaluated polyphenolics, and more specifically gallotannins as being the class of bioactive compounds (responsible for preventing or stopping cancer cells). Tannins are polyphenols that are often bitter or drying and found in such common foods as grape seed, wine and tea.
The study found that the cell cycle, which is the division cells go through, was interrupted. This is crucial information, Suzanne Talcott said, because it indicates a possible mechanism for how the cancer cells are prevented or stopped.
"For cells that may be on the verge of mutating or being damaged, mango polyphenolics prevent this kind of damage," she said.
The Talcotts hope to do a small clinical trial with individuals who have increased inflamation in their intestines with a higher risk for cancer.
"From there, if there is any proven efficacy, then we would do a larger trial to see if there is any clinical relevance," she said.
###
According to the National Mango Board, based in Winter Park, Fla., most mangoes consumed in the U.S. are produced in Mexico, Ecuador, Peru, Brazil, Guatemala and Haiti. Mangoes are native to southeast Asia and India and are produced in tropical climates. They were introduced to the U.S. in the late 1800s, and a few commercial acres still exist in California and Florida.
Tuesday, January 5, 2010
Eating fruit fights breast cancer
Eating fruit, such as pomegranates, that contain anti-aromatase phytochemicals reduces the incidence of hormone-dependent breast cancer, according to results of a study published in the January issue of Cancer Prevention Research, a journal of the American Association for Cancer Research.
Pomegranate is enriched in a series of compounds known as ellagitannins that, as shown in this study, appear to be responsible for the anti-proliferative effect of the pomegranate.
"Phytochemicals suppress estrogen production that prevents the proliferation of breast cancer cells and the growth of estrogen-responsive tumors," said principal investigator Shiuan Chen, Ph.D., director of the Division of Tumor Cell Biology and co-leader of the Breast Cancer Research Program at City of Hope in Duarte, Calif.
Previous research has shown that pomegranate juice — punica granatum L — is high in antioxidant activity, which is generally attributed to the fruit's high polyphenol content. Ellagic acid found in pomegranates inhibits aromatase, an enzyme that converts androgen to estrogen. Aromatase plays a key role in breast carcinogenesis; therefore, the growth of breast cancer is inhibited.
Chen, along with Lynn Adams, Ph.D., a research fellow at Beckman Research Institute of City of Hope, and colleagues, evaluated whether phytochemicals in pomegranates can suppress aromatase and ultimately inhibit cancer growth.
After screening and examining a panel of 10 ellagitannin-derived compounds in pomegranates, the investigators found that those compounds have the potential to prevent estrogen-responsive breast cancers. Urolithin B, which is a metabolite produced from ellagic acid and related compounds, significantly inhibited cell growth
"We were surprised by our findings," said Chen. "We previously found other fruits, such as grapes, to be capable of the inhibition of aromatase. But, phytochemicals in pomegranates and in grapes are different."
According to Gary Stoner, Ph.D., professor in the Department of Internal Medicine at Ohio State University, additional studies will be needed to confirm the chemopreventive action of Urolithin B against hormone-dependent breast cancer.
"This is an in vitro study in which relatively high levels of ellagitannin compounds were required to demonstrate an anti-proliferative effect on cultured breast cancer cells," said Stoner, who is not associated with this study. "It's not clear that these levels could be achieved in animals or in humans because the ellagitannins are not well absorbed into blood when provided in the diet."
Stoner believes these results are promising enough to suggest that more experiments with pomegranate in animals and humans are warranted.
Powel Brown, M.D., Ph.D., medical oncologist and chairman of the Clinical Cancer Prevention Department at the University of Texas M. D. Anderson Cancer Center, agreed with Stoner's sentiments and said these results are intriguing. He recommended that future studies focus on testing pomegranate juice for its effect on estrogen levels, menopausal symptoms, breast density or even as a cancer preventive agent.
"More research on the individual components and the combination of chemicals is needed to understand the potential risks and benefits of using pomegranate juice or isolated compounds for a health benefit or for cancer prevention," Brown said. "This study does suggest that studies of the ellagitannins from pomegranates should be continued."
Until then, Stoner said people "might consider consuming more pomegranates to protect against cancer development in the breast and perhaps in other tissues and organs."
Pomegranate is enriched in a series of compounds known as ellagitannins that, as shown in this study, appear to be responsible for the anti-proliferative effect of the pomegranate.
"Phytochemicals suppress estrogen production that prevents the proliferation of breast cancer cells and the growth of estrogen-responsive tumors," said principal investigator Shiuan Chen, Ph.D., director of the Division of Tumor Cell Biology and co-leader of the Breast Cancer Research Program at City of Hope in Duarte, Calif.
Previous research has shown that pomegranate juice — punica granatum L — is high in antioxidant activity, which is generally attributed to the fruit's high polyphenol content. Ellagic acid found in pomegranates inhibits aromatase, an enzyme that converts androgen to estrogen. Aromatase plays a key role in breast carcinogenesis; therefore, the growth of breast cancer is inhibited.
Chen, along with Lynn Adams, Ph.D., a research fellow at Beckman Research Institute of City of Hope, and colleagues, evaluated whether phytochemicals in pomegranates can suppress aromatase and ultimately inhibit cancer growth.
After screening and examining a panel of 10 ellagitannin-derived compounds in pomegranates, the investigators found that those compounds have the potential to prevent estrogen-responsive breast cancers. Urolithin B, which is a metabolite produced from ellagic acid and related compounds, significantly inhibited cell growth
"We were surprised by our findings," said Chen. "We previously found other fruits, such as grapes, to be capable of the inhibition of aromatase. But, phytochemicals in pomegranates and in grapes are different."
According to Gary Stoner, Ph.D., professor in the Department of Internal Medicine at Ohio State University, additional studies will be needed to confirm the chemopreventive action of Urolithin B against hormone-dependent breast cancer.
"This is an in vitro study in which relatively high levels of ellagitannin compounds were required to demonstrate an anti-proliferative effect on cultured breast cancer cells," said Stoner, who is not associated with this study. "It's not clear that these levels could be achieved in animals or in humans because the ellagitannins are not well absorbed into blood when provided in the diet."
Stoner believes these results are promising enough to suggest that more experiments with pomegranate in animals and humans are warranted.
Powel Brown, M.D., Ph.D., medical oncologist and chairman of the Clinical Cancer Prevention Department at the University of Texas M. D. Anderson Cancer Center, agreed with Stoner's sentiments and said these results are intriguing. He recommended that future studies focus on testing pomegranate juice for its effect on estrogen levels, menopausal symptoms, breast density or even as a cancer preventive agent.
"More research on the individual components and the combination of chemicals is needed to understand the potential risks and benefits of using pomegranate juice or isolated compounds for a health benefit or for cancer prevention," Brown said. "This study does suggest that studies of the ellagitannins from pomegranates should be continued."
Until then, Stoner said people "might consider consuming more pomegranates to protect against cancer development in the breast and perhaps in other tissues and organs."
Parity Among Prostate Cancer Treatments?
Report suggests similar effectiveness among options for managing low-risk prostate cancer
A comprehensive appraisal of the management and treatment options for low-risk prostate cancer found that the rates of survival and tumor recurrence are similar among the most common treatment approaches, although costs can vary considerably. The report was prepared by the Institute for Clinical and Economic Review (ICER), a leader in comparative effectiveness research based at the Massachusetts General Hospital's Institute for Technology Assessment.
Bringing together the findings from three previous reviews completed by ICER, the final summary report, "Management Options for Low-Risk Prostate Cancer: A Report on Comparative Effectiveness and Value," compares multiple approaches to managing the most common non-skin cancer among U.S. men:
• Active surveillance, a "watch and wait" strategy with careful monitoring and referral for surgery or radiation if necessary;
• Radical prostatectomy, surgical removal of the prostate via traditional "open" or robot-assisted approaches;
• Brachytherapy, implantation of radioactive seeds in the prostate;
• Intensity-modulated radiation therapy (IMRT) and proton therapy, two forms of external radiation therapy.
The ICER review found that there are no definitive head-to-head studies comparing these options, but that accumulated evidence from multiple studies over the years suggests that overall survival and the rate of cancer recurrence are quite similar among all options, including active surveillance. There are different risks for certain side effects and complications, but no treatment option stands out as superior overall. Because low-risk prostate cancer is typically slow-growing and may not cause any symptoms, active surveillance is a reasonable option, particularly for men 65 and older, approximately half of whom will never have their cancer progress to the point of requiring treatment.
"ICER's review provides a welcome objective summary of what we know and what we don't know that can help men in conversations with their doctor," stated David Most, PhD, prostate cancer survivor and Founder and President of Health Information Research, Inc., who was a member of the Evidence Review Group that participated in the ICER appraisal process. "Given the numerous sources of information we have on the different management options, it really can be difficult to know what to do. Having a report like this from ICER will help patients make informed healthcare decisions that reflect their values about the risks and benefits among the different options."
The ICER report included a review of published literature on the treatment of low-risk prostate cancer as well as simulation modeling to project the long-term effects of each treatment approach. The evidence on radical prostatectomy, brachytherapy, and IMRT was judged to demonstrate comparable overall clinical effectiveness for most men, while there was not enough evidence to date to make a comparison on proton therapy.
The evidence on active surveillance was stronger for older men, and therefore ICER rated its clinical effectiveness as comparable to immediate treatment for men 65 and over. Long-term outcomes with active surveillance are not yet available, but for younger men active surveillance may still be a reasonable option given that surgery or radiation can be done if regular blood tests and prostate biopsies suggest the cancer is growing.
The ICER report also found that, based on Medicare payments, active surveillance costs approximately $300-$1,000 per year, while brachytherapy and radical prostatectomy procedures cost approximately $10,000. IMRT and proton therapy are more expensive, costing $20,000 and $35,000 per treatment course, respectively.
A comprehensive appraisal of the management and treatment options for low-risk prostate cancer found that the rates of survival and tumor recurrence are similar among the most common treatment approaches, although costs can vary considerably. The report was prepared by the Institute for Clinical and Economic Review (ICER), a leader in comparative effectiveness research based at the Massachusetts General Hospital's Institute for Technology Assessment.
Bringing together the findings from three previous reviews completed by ICER, the final summary report, "Management Options for Low-Risk Prostate Cancer: A Report on Comparative Effectiveness and Value," compares multiple approaches to managing the most common non-skin cancer among U.S. men:
• Active surveillance, a "watch and wait" strategy with careful monitoring and referral for surgery or radiation if necessary;
• Radical prostatectomy, surgical removal of the prostate via traditional "open" or robot-assisted approaches;
• Brachytherapy, implantation of radioactive seeds in the prostate;
• Intensity-modulated radiation therapy (IMRT) and proton therapy, two forms of external radiation therapy.
The ICER review found that there are no definitive head-to-head studies comparing these options, but that accumulated evidence from multiple studies over the years suggests that overall survival and the rate of cancer recurrence are quite similar among all options, including active surveillance. There are different risks for certain side effects and complications, but no treatment option stands out as superior overall. Because low-risk prostate cancer is typically slow-growing and may not cause any symptoms, active surveillance is a reasonable option, particularly for men 65 and older, approximately half of whom will never have their cancer progress to the point of requiring treatment.
"ICER's review provides a welcome objective summary of what we know and what we don't know that can help men in conversations with their doctor," stated David Most, PhD, prostate cancer survivor and Founder and President of Health Information Research, Inc., who was a member of the Evidence Review Group that participated in the ICER appraisal process. "Given the numerous sources of information we have on the different management options, it really can be difficult to know what to do. Having a report like this from ICER will help patients make informed healthcare decisions that reflect their values about the risks and benefits among the different options."
The ICER report included a review of published literature on the treatment of low-risk prostate cancer as well as simulation modeling to project the long-term effects of each treatment approach. The evidence on radical prostatectomy, brachytherapy, and IMRT was judged to demonstrate comparable overall clinical effectiveness for most men, while there was not enough evidence to date to make a comparison on proton therapy.
The evidence on active surveillance was stronger for older men, and therefore ICER rated its clinical effectiveness as comparable to immediate treatment for men 65 and over. Long-term outcomes with active surveillance are not yet available, but for younger men active surveillance may still be a reasonable option given that surgery or radiation can be done if regular blood tests and prostate biopsies suggest the cancer is growing.
The ICER report also found that, based on Medicare payments, active surveillance costs approximately $300-$1,000 per year, while brachytherapy and radical prostatectomy procedures cost approximately $10,000. IMRT and proton therapy are more expensive, costing $20,000 and $35,000 per treatment course, respectively.
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