Four healthy lifestyle factors—never smoking, maintaining a healthy weight, exercising regularly and following a healthy diet—together appear to be associated with as much as an 80 percent reduction in the risk of developing the most common and deadly chronic diseases, according to a report in the August 10/24 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
Cardiovascular disease, cancer and diabetes—chronic diseases that together account for most deaths—are largely preventable, according to background information in the article. "An impressive body of research has implicated modifiable lifestyle factors such as smoking, physical activity, diet and body weight in the causes of these diseases," the authors write.
To further describe the reduction in risk associated with these factors, Earl S. Ford, M.D., M.P.H., of the Centers for Disease Control and Prevention, Atlanta, and colleagues assessed data from 23,513 German adults age 35 to 65. At the beginning of the European Prospective Investigation Into Cancer and Nutrition–Potsdam (EPIC-Potsdam) study—between 1994 and 1998—participants completed an assessment of their body weight and height, a personal interview that included questions about diseases, a questionnaire on sociodemographic and lifestyle characteristics and a food frequency questionnaire.
Their responses were assessed for adherence to four healthy lifestyle factors: never smoking, having a body mass index lower than 30, exercising for at least three and a half hours per week and following healthy dietary principles (for example, having a diet with high consumption of fruits and vegetables while limiting meat consumption). Follow-up questionnaires were administered every two to three years.
Most participants had one to three of these health factors, fewer than 4 percent had zero healthy factors and 9 percent had all four factors. Over an average of 7.8 years of follow-up, 2,006 participants developed new cases of diabetes (3.7 percent), heart attack (0.9 percent), stroke (0.8 percent) or cancer (3.8 percent).
After adjusting for age, sex, education level and occupation, individuals with more healthy lifestyle factors were less likely to develop chronic diseases. Participants who had all four factors at the beginning of the study had a 78 percent lower risk of developing any of the chronic diseases during the follow-up period than those who had none of the healthy factors. The four factors were associated with a 93 percent reduced risk of diabetes, 81 percent reduced risk of heart attack, 50 percent reduced risk of stroke and 36 percent reduced risk of cancer.
The largest reduction in risk was associated with having a BMI lower than 30, followed by never smoking, at least 3.5 hours of physical activity and then adhering to good dietary principles.
"Our results reinforce current public health recommendations to avoid smoking, to maintain a healthy weight, to engage in physical activity appropriately and to eat adequate amounts of fruits and vegetables and foods containing whole grains and to partake of red meat prudently," the authors write. "Because the roots of these factors often originate during the formative stages of life, it is especially important to start early in teaching the important lessons concerning healthy living."
Monday, August 10, 2009
Friday, August 7, 2009
Beetroot juice boosts stamina
Beetroot juice boosts stamina
Drinking beetroot juice boosts your stamina and could help you exercise for up to 16% longer. A University of Exeter led-study shows for the first time how the nitrate contained in beetroot juice leads to a reduction in oxygen uptake, making exercise less tiring.
The study reveals that drinking beetroot juice reduces oxygen uptake to an extent that cannot be achieved by any other known means, including training.
The research team believes that the findings could be of great interest to endurance athletes. They could also be relevant to elderly people or those with cardiovascular, respiratory or metabolic diseases.
The research team conducted their study with eight men aged between 19 and 38. They were given 500ml per day of organic beetroot juice for six consecutive days before completing a series of tests, involving cycling on an exercise bike. On another occasion, they were given a placebo of blackcurrant cordial for six consecutive days before completing the same cycling tests.
After drinking beetroot juice the group was able to cycle for an average of 11.25 minutes, which is 92 seconds longer than when they were given the placebo. This would translate into an approximate 2% reduction in the time taken to cover a set distance. The group that had consumed the beetroot juice also had lower resting blood pressure.
The researchers are not yet sure of the exact mechanism that causes the nitrate in the beetroot juice to boost stamina. However, they suspect it could be a result of the nitrate turning into nitric oxide in the body, reducing the oxygen cost of exercise.
The research was carried out by the University of Exeter and Peninsula Medical School and published in the Journal of Applied Physiology. The research team now hopes to conduct further studies to try to understand in more detail the effects of nitrate-rich foods on exercise physiology.
Corresponding author of the study, Professor Andy Jones of the University of Exeter's School of Sport and Health Sciences, said: "Our study is the first to show that nitrate-rich food can increase exercise endurance. We were amazed by the effects of beetroot juice on oxygen uptake because these effects cannot be achieved by any other known means, including training. I am sure professional and amateur athletes will be interested in the results of this research. I am also keen to explore the relevance of the findings to those people who suffer from poor fitness and may be able to use dietary supplements to help them go about their daily lives."
Drinking beetroot juice boosts your stamina and could help you exercise for up to 16% longer. A University of Exeter led-study shows for the first time how the nitrate contained in beetroot juice leads to a reduction in oxygen uptake, making exercise less tiring.
The study reveals that drinking beetroot juice reduces oxygen uptake to an extent that cannot be achieved by any other known means, including training.
The research team believes that the findings could be of great interest to endurance athletes. They could also be relevant to elderly people or those with cardiovascular, respiratory or metabolic diseases.
The research team conducted their study with eight men aged between 19 and 38. They were given 500ml per day of organic beetroot juice for six consecutive days before completing a series of tests, involving cycling on an exercise bike. On another occasion, they were given a placebo of blackcurrant cordial for six consecutive days before completing the same cycling tests.
After drinking beetroot juice the group was able to cycle for an average of 11.25 minutes, which is 92 seconds longer than when they were given the placebo. This would translate into an approximate 2% reduction in the time taken to cover a set distance. The group that had consumed the beetroot juice also had lower resting blood pressure.
The researchers are not yet sure of the exact mechanism that causes the nitrate in the beetroot juice to boost stamina. However, they suspect it could be a result of the nitrate turning into nitric oxide in the body, reducing the oxygen cost of exercise.
The research was carried out by the University of Exeter and Peninsula Medical School and published in the Journal of Applied Physiology. The research team now hopes to conduct further studies to try to understand in more detail the effects of nitrate-rich foods on exercise physiology.
Corresponding author of the study, Professor Andy Jones of the University of Exeter's School of Sport and Health Sciences, said: "Our study is the first to show that nitrate-rich food can increase exercise endurance. We were amazed by the effects of beetroot juice on oxygen uptake because these effects cannot be achieved by any other known means, including training. I am sure professional and amateur athletes will be interested in the results of this research. I am also keen to explore the relevance of the findings to those people who suffer from poor fitness and may be able to use dietary supplements to help them go about their daily lives."
Tuesday, August 4, 2009
Millions of US children low in vitamin D
Seven out of ten U.S. children have low levels of vitamin D, raising their risk of bone and heart disease, according to a study of over 6,000 children by researchers at Albert Einstein College of Medicine of Yeshiva University. The striking findings suggest that vitamin D deficiency could place millions of children at risk for high blood pressure and other risk factors for heart disease. The study is published today in the online version of Pediatrics.
Vitamin D deficiency was thought to be relatively rare in the U.S. However, recent studies have documented this growing problem in adults. With cases of rickets (a bone disease in infants caused by low vitamin D levels) on the rise, it became clear that many children were also not getting enough of this essential vitamin, which is needed for healthy bone growth, among other biological processes.
"Several small studies had found a high prevalence of vitamin D deficiency in specific populations of children, but no one had examined this issue nationwide," says study leader Michal L. Melamed, M.D., assistant professor of medicine and of epidemiology & population health at Einstein. Dr. Melamed has published extensively on the importance of vitamin D.
To learn more about the prevalence of vitamin D deficiency (defined as less than 15 ng/mL of blood) and vitamin D insufficiency (15 to 29 ng/mL), the researchers analyzed data on more than 6,000 children, ages one to 21, collected by the National Health and Nutrition Examination Survey (NHANES) 2001-2004.
The researchers found that 9 percent of the study sample, equivalent to 7.6 million children across the U.S., was vitamin D deficient, while another 61 percent, or 50.8 million, was vitamin D insufficient. Low vitamin D levels were especially common in children who were older, female, African-American, Mexican-American, obese, drank milk less than once a week, or spent more than four hours a day watching TV, playing videogames, or using computers.
The researchers also found that low levels of vitamin D deficiency were associated with higher parathyroid hormone levels, a marker of bone health, higher systolic blood pressure, and lower serum calcium and HDL (good) cholesterol levels, which are key risk factors for heart disease.
"We expected the prevalence of vitamin D deficiency would be high, but the magnitude of the problem nationwide was shocking," says lead author Juhi Kumar, M.D., M.P.H., a fellow in pediatrics at Children's Hospital at Montefiore Medical Center, The University Hospital and Academic Medical Center for Albert Einstein College of Medicine. Dr. Kumar will become an assistant professor of pediatrics at Weill Cornell Medical College in August, 2009.
"We know from earlier NHANES data that vitamin D levels have declined over the last 20 years," says Dr. Melamed. "Kids have more sedentary lifestyles today and are not spending as much time outdoors. The widespread use of sunscreens, which block UV-B rays, has only compounded the problem." The body uses UV-B sunlight to convert a form of cholesterol in the skin into vitamin D.
Dr. Melamed recommends that children should consume more foods rich in vitamin D, such as milk and fish. "But it's very hard to get enough vitamin D from dietary sources alone," she says.
Vitamin D supplementation can help. In the study, children who took vitamin D supplements (400 IU/day) were less likely to be deficient in the vitamin. However, only four percent of the study population actually used supplements. The American Academy of Pediatrics, which recently updated its vitamin D guidelines, now recommends that infants, children, and teens should take 400 IU per day in supplement form.
Supplements are especially important for those living in the country's northern regions where the sun may be too weak to maintain healthy vitamin D levels. Supplements are also critical for infants who are breast-fed, say the researchers. Breast milk contains relatively little vitamin D, while formula is fortified with the vitamin.
The authors recommend that pediatricians should routinely screen high-risk children for vitamin D deficiency, and that parents should ensure that their kids get adequate amounts of the vitamin through a combination of diet, supplements, and exposure to sunlight.
"The message for pediatricians is that vitamin D deficiency is a real problem with consequences not only for bone health but also potentially for long-term cardiovascular health. Pediatricians should be screening children for vitamin D levels, especially in the high-risk populations," says Dr. Kumar. A study co-led by Dr. Melamed and published in the Archives of Internal Medicine in August 2008 reported that individuals with low levels of vitamin D may have an increased risk of death from all causes.
As for parents, says Dr. Melamed, "It would good for them to turn off the TV and send their kids outside. Just 15 to 20 minutes a day should be enough. And unless they burn easily, don't put sunscreen on them until they've been out in the sun for 10 minutes, so they get the good stuff but not sun damage."
Vitamin D deficiency was thought to be relatively rare in the U.S. However, recent studies have documented this growing problem in adults. With cases of rickets (a bone disease in infants caused by low vitamin D levels) on the rise, it became clear that many children were also not getting enough of this essential vitamin, which is needed for healthy bone growth, among other biological processes.
"Several small studies had found a high prevalence of vitamin D deficiency in specific populations of children, but no one had examined this issue nationwide," says study leader Michal L. Melamed, M.D., assistant professor of medicine and of epidemiology & population health at Einstein. Dr. Melamed has published extensively on the importance of vitamin D.
To learn more about the prevalence of vitamin D deficiency (defined as less than 15 ng/mL of blood) and vitamin D insufficiency (15 to 29 ng/mL), the researchers analyzed data on more than 6,000 children, ages one to 21, collected by the National Health and Nutrition Examination Survey (NHANES) 2001-2004.
The researchers found that 9 percent of the study sample, equivalent to 7.6 million children across the U.S., was vitamin D deficient, while another 61 percent, or 50.8 million, was vitamin D insufficient. Low vitamin D levels were especially common in children who were older, female, African-American, Mexican-American, obese, drank milk less than once a week, or spent more than four hours a day watching TV, playing videogames, or using computers.
The researchers also found that low levels of vitamin D deficiency were associated with higher parathyroid hormone levels, a marker of bone health, higher systolic blood pressure, and lower serum calcium and HDL (good) cholesterol levels, which are key risk factors for heart disease.
"We expected the prevalence of vitamin D deficiency would be high, but the magnitude of the problem nationwide was shocking," says lead author Juhi Kumar, M.D., M.P.H., a fellow in pediatrics at Children's Hospital at Montefiore Medical Center, The University Hospital and Academic Medical Center for Albert Einstein College of Medicine. Dr. Kumar will become an assistant professor of pediatrics at Weill Cornell Medical College in August, 2009.
"We know from earlier NHANES data that vitamin D levels have declined over the last 20 years," says Dr. Melamed. "Kids have more sedentary lifestyles today and are not spending as much time outdoors. The widespread use of sunscreens, which block UV-B rays, has only compounded the problem." The body uses UV-B sunlight to convert a form of cholesterol in the skin into vitamin D.
Dr. Melamed recommends that children should consume more foods rich in vitamin D, such as milk and fish. "But it's very hard to get enough vitamin D from dietary sources alone," she says.
Vitamin D supplementation can help. In the study, children who took vitamin D supplements (400 IU/day) were less likely to be deficient in the vitamin. However, only four percent of the study population actually used supplements. The American Academy of Pediatrics, which recently updated its vitamin D guidelines, now recommends that infants, children, and teens should take 400 IU per day in supplement form.
Supplements are especially important for those living in the country's northern regions where the sun may be too weak to maintain healthy vitamin D levels. Supplements are also critical for infants who are breast-fed, say the researchers. Breast milk contains relatively little vitamin D, while formula is fortified with the vitamin.
The authors recommend that pediatricians should routinely screen high-risk children for vitamin D deficiency, and that parents should ensure that their kids get adequate amounts of the vitamin through a combination of diet, supplements, and exposure to sunlight.
"The message for pediatricians is that vitamin D deficiency is a real problem with consequences not only for bone health but also potentially for long-term cardiovascular health. Pediatricians should be screening children for vitamin D levels, especially in the high-risk populations," says Dr. Kumar. A study co-led by Dr. Melamed and published in the Archives of Internal Medicine in August 2008 reported that individuals with low levels of vitamin D may have an increased risk of death from all causes.
As for parents, says Dr. Melamed, "It would good for them to turn off the TV and send their kids outside. Just 15 to 20 minutes a day should be enough. And unless they burn easily, don't put sunscreen on them until they've been out in the sun for 10 minutes, so they get the good stuff but not sun damage."
Mounting evidence of fish oil's heart health benefits
Researchers set forth recommendations for daily intake
There is mounting evidence that omega-3 fatty acids from fish or fish oil supplements not only help prevent cardiovascular diseases in healthy individuals, but also reduce the incidence of cardiac events and mortality in patients with existing heart disease. A new study, published in the August 11, 2009, issue of the Journal of the American College of Cardiology, extensively reviews data from a broad range of studies in tens of thousands of patients and sets forth suggested daily targets for omega-3 consumption.
"This isn't just hype; we now have tremendous and compelling evidence from very large studies, some dating back 20 and 30 years, that demonstrate the protective benefits of omega-3 fish oil in multiple aspects of preventive cardiology," said Carl Lavie, M.D., F.A.C.C., medical director of Cardiac Rehabilitation and Prevention, Ochsner Medical Center, New Orleans, LA, and lead author of the article. "The strongest evidence of a cardioprotective effect of omega-3s appears in patients with established cardiovascular disease and following a heart attack with up to a 30 percent reduction in CV-related death."
Dietary intake of fish oil can also decrease the risk of atherosclerosis, arrhythmias, heart attack, sudden cardiac death and even health failure. Dr. Lavie adds that although there is a smaller benefit in reducing heart failure death—9 percent mortality benefit in a major recent randomized controlled trial—this is still very impressive given patients' grave prognosis.
"If we translate this finding, it means that we only need to treat 56 patients for four years to prevent one death," he said. "And we are talking about a very safe and relatively inexpensive therapy."
Most of the evidence for the cardioprotective benefits supports the use of DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), the long-chain fatty acids in the omega-3 family. According to Dr. Lavie, EPA and DHA work by getting into the membranes of cells and, in doing so, may help to improve the heart's electrical activity, vascular tone, plaque stabilization and blood pressure, among other benefits. Studies show that the reduction in CV events is inversely related to the tissue level EPA and, even more so, DHA.
Based on these findings, and because the body does not produce its own essential fatty acids, the authors recommend that healthy individuals should consume 500 mg daily of omega-3 fish oil containing EPA and DHA, and people with known heart disease or heart failure aim for at least 800 to 1,000 mg daily.
"There are clear health and heart benefits associated with increasing one's intake of foods that are rich in Omega-3s, including oily fish like salmon, sardines, trout, herring, and oysters" said Dr. Lavie "Patients should talk with their doctors about whether a fish oil supplement is needed to get the right amount and, in turn, benefit from the associated cardiovascular protection."
Dr. Lavie and his team came across only a few negative studies, including a recent one that showed no benefit in post-MI patients, but it has raised the possibility that omega-3 fatty acids may not provide as much additional protective benefits in low-risk patients already receiving extensive and rigorous post-MI therapies. "It was a one-year study that enrolled fewer than 4,000 patients and the majority were using aspirin, clopidogrel, statins, beta-blockers and ACE-inhibitors—the best of modern medicine," he said. "It may be that their risk was so low to start, that a larger study with longer follow-up would be required to better assess the true efficacy of omega-3 in such relatively low-risk patients."
Authors say further studies are needed to investigate and determine optimal dosages, as well as the relative ration of DHA and EPA that provides maximal heart protection in those at risk of cardiovascular disease, and in the treatment of atherosclerosis, arrhythmias and heart attacks.
Interestingly, culture has historically played a role; sometimes dubbed the "Eskimo factor," research shows cultures that have traditionally supported a diet rich in fish oil (Asian and Alaskan American populations) had a lower prevalence of cardiovascular disease and mortality, including a reduced prevalence of atherosclerosis and heart disease, compared to European and United States populations where consumption of fish is lower. Ironically, the introduction of Western dietary practices into Asian and Native American cultures may be diluting the cardioprotective benefits enjoyed by these populations by both reducing the overall intake of fish oils, as well as overwhelming its benefits with other deleterious dietary practices, including high intakes of saturated and trans fats and cholesterol.
There is mounting evidence that omega-3 fatty acids from fish or fish oil supplements not only help prevent cardiovascular diseases in healthy individuals, but also reduce the incidence of cardiac events and mortality in patients with existing heart disease. A new study, published in the August 11, 2009, issue of the Journal of the American College of Cardiology, extensively reviews data from a broad range of studies in tens of thousands of patients and sets forth suggested daily targets for omega-3 consumption.
"This isn't just hype; we now have tremendous and compelling evidence from very large studies, some dating back 20 and 30 years, that demonstrate the protective benefits of omega-3 fish oil in multiple aspects of preventive cardiology," said Carl Lavie, M.D., F.A.C.C., medical director of Cardiac Rehabilitation and Prevention, Ochsner Medical Center, New Orleans, LA, and lead author of the article. "The strongest evidence of a cardioprotective effect of omega-3s appears in patients with established cardiovascular disease and following a heart attack with up to a 30 percent reduction in CV-related death."
Dietary intake of fish oil can also decrease the risk of atherosclerosis, arrhythmias, heart attack, sudden cardiac death and even health failure. Dr. Lavie adds that although there is a smaller benefit in reducing heart failure death—9 percent mortality benefit in a major recent randomized controlled trial—this is still very impressive given patients' grave prognosis.
"If we translate this finding, it means that we only need to treat 56 patients for four years to prevent one death," he said. "And we are talking about a very safe and relatively inexpensive therapy."
Most of the evidence for the cardioprotective benefits supports the use of DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), the long-chain fatty acids in the omega-3 family. According to Dr. Lavie, EPA and DHA work by getting into the membranes of cells and, in doing so, may help to improve the heart's electrical activity, vascular tone, plaque stabilization and blood pressure, among other benefits. Studies show that the reduction in CV events is inversely related to the tissue level EPA and, even more so, DHA.
Based on these findings, and because the body does not produce its own essential fatty acids, the authors recommend that healthy individuals should consume 500 mg daily of omega-3 fish oil containing EPA and DHA, and people with known heart disease or heart failure aim for at least 800 to 1,000 mg daily.
"There are clear health and heart benefits associated with increasing one's intake of foods that are rich in Omega-3s, including oily fish like salmon, sardines, trout, herring, and oysters" said Dr. Lavie "Patients should talk with their doctors about whether a fish oil supplement is needed to get the right amount and, in turn, benefit from the associated cardiovascular protection."
Dr. Lavie and his team came across only a few negative studies, including a recent one that showed no benefit in post-MI patients, but it has raised the possibility that omega-3 fatty acids may not provide as much additional protective benefits in low-risk patients already receiving extensive and rigorous post-MI therapies. "It was a one-year study that enrolled fewer than 4,000 patients and the majority were using aspirin, clopidogrel, statins, beta-blockers and ACE-inhibitors—the best of modern medicine," he said. "It may be that their risk was so low to start, that a larger study with longer follow-up would be required to better assess the true efficacy of omega-3 in such relatively low-risk patients."
Authors say further studies are needed to investigate and determine optimal dosages, as well as the relative ration of DHA and EPA that provides maximal heart protection in those at risk of cardiovascular disease, and in the treatment of atherosclerosis, arrhythmias and heart attacks.
Interestingly, culture has historically played a role; sometimes dubbed the "Eskimo factor," research shows cultures that have traditionally supported a diet rich in fish oil (Asian and Alaskan American populations) had a lower prevalence of cardiovascular disease and mortality, including a reduced prevalence of atherosclerosis and heart disease, compared to European and United States populations where consumption of fish is lower. Ironically, the introduction of Western dietary practices into Asian and Native American cultures may be diluting the cardioprotective benefits enjoyed by these populations by both reducing the overall intake of fish oils, as well as overwhelming its benefits with other deleterious dietary practices, including high intakes of saturated and trans fats and cholesterol.
Heavy drinkers face significantly higher cancer risk
Montreal study links heavy consumption of beer and spirits to 6 different cancers
Heavy drinkers of beer and spirits face a much higher risk of developing cancer than the population at large, says a group of Montreal epidemiologists and cancer researchers. Their findings show that people in the highest consumption category increased their risk of developing oesophageal cancer sevenfold, colon cancer by 80% and even lung cancer by 50%.
In all, the researchers found statistically significant relationships between heavy consumption of beer and spririts and six different cancers. Moderate drinking (i.e. less than daily) and wine consumption did not show the same effects, however.
"We looked at the data in two ways," said Benedetti, an assistant professor at McGill's Departments of Medicine and of Epidemiology, Biostatistics and Occupational Health. "We compared people who drank heavily to our reference group, who abstained or drank only very occasionally. We also looked for trends across our categories: non-drinkers, weekly drinkers and daily drinkers.
The results were astounding. "We saw increased risk for esophageal cancer, stomach cancer, colon cancer, liver cancer, pancreatic cancer, lung cancer and prostate cancer," Benedetti added. "The strongest risk was for esophageal and liver cancer."
"This study crystalizes many strands of evidence from different studies on different types of cancer and alcohol consumption," said Dr. Jack Siematycki, professor, Canada Research Chair and Guzzo Chair in Environment and Cancer, at the Université de Montréal.
The researchers used data originally collected for a large occupational cancer study conducted in Montreal in the 1980s. The information was a treasure-trove, said Benedetti.
"Lifetime interviews were conducted with people about their job histories, and detailed information about all the things they could have been exposed to was collected," she explained. "As it turns out, the data also included information about non-occupational factors such as drinking alcohol, smoking cigarettes, diet and socio-economic status, among others."
Benedetti, the study's lead author, conducted this research while still a postdoctorial fellow under the supervision of her co-authors, Dr. Siemiatycki and Dr. Parent. Their results were published in the current issue of the journal Cancer Detection and Prevention.
"For the most part we showed that light drinkers were less affected or not affected at all," said Benedetti. "It is people who drink every day or multiple times a day who are at risk. This adds to the growing body of evidence that heavy drinking is extremely unhealthy in so many ways. Cancer very much included."
The way you eat may affect your risk for breast cancer
How you eat may be just as important as how much you eat, if mice studies are any clue.
Cancer researchers have long studied the role of diet on breast cancer risk, but results to date have been mixed. New findings published in Cancer Prevention Research, a journal of the American Association for Cancer Research, suggest the method by which calories are restricted may be more important for cancer protection than the actual overall degree of calorie restriction.
"Understanding how calorie restriction provides protection against the development of mammary tumors should help us identify pathways that could be targeted for chemoprevention studies," said Margot P. Cleary, Ph.D., professor at the Hormel Institute, University of Minnesota. "Further identification of serum factors that are involved in tumor development would possibly provide a way to identify at risk individuals and target interventions to these people."
Previous studies have shown that intermittent calorie restriction provided greater protection from mammary tumor development than did the same overall degree of restriction, which was implemented in a chronic fashion. The researchers compared changes of a growth factor (IGF-1) in relationship to these two calorie restriction methods — chronic and intermittent — and tumor development beginning in 10-week old female mice at risk to develop mammary tumors. Their hope was to explain why intermittent restriction is more effective.
The overall degree of restriction was 25 percent reduction compared to control mice. Mammary tumor incidence was 71 percent in the control mice who ate the amount of food they wanted, 35 percent among those who were chronically restricted and only nine percent in those who intermittently restricted calories.
The researchers were initially surprised by these findings for several reasons. First, the prevailing wisdom is that the degree of protection from calorie restriction is proportional to the degree of mammary tumor prevention. Second, they originally thought that intermittent calorie restriction might enhance tumor growth due to growth factors being secreted in response to re-feeding, Cleary said.
In an accompanying editorial also published in Cancer Prevention Research, Michael Pollak, M.D., stated that some major challenges of pharmacologic approaches to cancer prevention and/or treatment include defining the underlying causes and determining the relevance of these caloric restriction methods. Pollak is professor of oncology at McGill University and director of the Cancer Prevention Center at the Jewish General Hospital, both in Montreal.
This study "contributes to accumulating evidence that caloric restriction acts by altering hormone levels rather than by directly starving cancers of energy. In particular, lower levels of insulin are associated with reduced food intake, and this may be protective," said Pollak, who is also an editorial board member for Cancer Prevention Research.
In the editorial Pollak wrote: "there is reason for concern that the 'obesity epidemic' may lead to an increased prevalence of a hormonal profile associated with elevated cancer risk and/or an adverse cancer prognosis. Therefore, in addition to its well-known general health benefits, maintaining an ideal body weight is also important in the specific contexts of cancer prevention and improving the prognosis of cancer patients."
Based on varied findings from clinical trials, Pollak suggested that lifestyle and pharmacologic methods to reduce IGF-1 and insulin deserve ongoing investigations. Cleary agreed, stating that these results may provide interest to more aggressively pursue cancer prevention studies related to calorie restriction.
"Humans frequently regain lost weight discouraging the application of calorie restriction protocols for disease prevention," she said. "We hope these studies will identify biomarkers and/or pathways that could be used in human studies to determine agents that would mimic calorie restriction."
Cancer researchers have long studied the role of diet on breast cancer risk, but results to date have been mixed. New findings published in Cancer Prevention Research, a journal of the American Association for Cancer Research, suggest the method by which calories are restricted may be more important for cancer protection than the actual overall degree of calorie restriction.
"Understanding how calorie restriction provides protection against the development of mammary tumors should help us identify pathways that could be targeted for chemoprevention studies," said Margot P. Cleary, Ph.D., professor at the Hormel Institute, University of Minnesota. "Further identification of serum factors that are involved in tumor development would possibly provide a way to identify at risk individuals and target interventions to these people."
Previous studies have shown that intermittent calorie restriction provided greater protection from mammary tumor development than did the same overall degree of restriction, which was implemented in a chronic fashion. The researchers compared changes of a growth factor (IGF-1) in relationship to these two calorie restriction methods — chronic and intermittent — and tumor development beginning in 10-week old female mice at risk to develop mammary tumors. Their hope was to explain why intermittent restriction is more effective.
The overall degree of restriction was 25 percent reduction compared to control mice. Mammary tumor incidence was 71 percent in the control mice who ate the amount of food they wanted, 35 percent among those who were chronically restricted and only nine percent in those who intermittently restricted calories.
The researchers were initially surprised by these findings for several reasons. First, the prevailing wisdom is that the degree of protection from calorie restriction is proportional to the degree of mammary tumor prevention. Second, they originally thought that intermittent calorie restriction might enhance tumor growth due to growth factors being secreted in response to re-feeding, Cleary said.
In an accompanying editorial also published in Cancer Prevention Research, Michael Pollak, M.D., stated that some major challenges of pharmacologic approaches to cancer prevention and/or treatment include defining the underlying causes and determining the relevance of these caloric restriction methods. Pollak is professor of oncology at McGill University and director of the Cancer Prevention Center at the Jewish General Hospital, both in Montreal.
This study "contributes to accumulating evidence that caloric restriction acts by altering hormone levels rather than by directly starving cancers of energy. In particular, lower levels of insulin are associated with reduced food intake, and this may be protective," said Pollak, who is also an editorial board member for Cancer Prevention Research.
In the editorial Pollak wrote: "there is reason for concern that the 'obesity epidemic' may lead to an increased prevalence of a hormonal profile associated with elevated cancer risk and/or an adverse cancer prognosis. Therefore, in addition to its well-known general health benefits, maintaining an ideal body weight is also important in the specific contexts of cancer prevention and improving the prognosis of cancer patients."
Based on varied findings from clinical trials, Pollak suggested that lifestyle and pharmacologic methods to reduce IGF-1 and insulin deserve ongoing investigations. Cleary agreed, stating that these results may provide interest to more aggressively pursue cancer prevention studies related to calorie restriction.
"Humans frequently regain lost weight discouraging the application of calorie restriction protocols for disease prevention," she said. "We hope these studies will identify biomarkers and/or pathways that could be used in human studies to determine agents that would mimic calorie restriction."
High cholesterol in midlife= late-life dementia
High cholesterol in midlife raises risk of late-life dementia, Kaiser Permanente study finds
Largest, longest study shows even moderately elevated cholesterol level boosts dementia risk
Elevated cholesterol levels in midlife – even levels considered only borderline elevated – significantly increase the risk of Alzheimer's disease and vascular dementia later in life, according to a new study by researchers at Kaiser Permanente's Division of Research and the University of Kuopio in Finland. The study appears in the journal Dementia & Geriatric Cognitive Disorders.
The four-decade study of 9,844 men and women found that having high cholesterol in midlife (240 or higher milligrams per deciliter of blood) increases, by 66 percent, the risk for Alzheimer's disease later in life. Even borderline cholesterol levels (200 – 239 mg/dL) in midlife raised risk for late-life vascular dementia by nearly the same amount: 52 percent. Vascular dementia, the second most common form of dementia after Alzheimer's disease, is a group of dementia syndromes caused by conditions affecting the blood supply to the brain. Scientists are still trying to pinpoint the genetic factors and lifestyle causes for Alzheimer's disease.
By measuring cholesterol levels in 1964 to 1973 based on the 2002 Adult Treatment Panel III guidelines (the current practice standard) when the Kaiser Permanente Northern California members were 40 to 45 years old, then following the participants for 40 years, this study is the largest long-term study with the most diverse population to examine the midlife cholesterol levels and late-life dementia. It is also the first study to look at borderline high cholesterol levels and vascular dementia, rather than just Alzheimer's disease.
"Our study shows that even moderately high cholesterol levels in your 40s puts people at greater risk for Alzheimer's disease and vascular dementia decades later," said the study's senior author. Rachel Whitmer, Ph.D., a research scientist and epidemiologist at the Kaiser Permanente Division of Research in Oakland, Calif. "Considering that nearly 100 million Americans have either high or borderline cholesterol levels, this is a disturbing finding. The good news here is that what is good for the heart is also good for the mind, and this is an early risk factor for dementia that can be modified and managed by lowering cholesterol through healthy lifestyle changes."
This study, funded by the National Institutes of Health, adds to other research emphasizing the importance of addressing dementia risk factors in midlife, before an underlying disease or symptoms appear, the researchers said.
"Our findings add to the existing body of evidence on a degree of overlap between two dementia types in terms of risk factors, symptoms and neuropathology," said the study's lead author, Alina Solomon, MD, a researcher with the Department of Neurology at the University of Kuopio, Finland. "Dementia and cardiovascular disease are common major health problems, share several risk factors and often occur simultaneously, interacting with one another. A holistic approach that addresses multiple major health problems simultaneously is needed to effectively manage these disorders."
The study tracked members of Kaiser Permanente's Northern California Medical Group from 1967 to 2007 by using the multiphasic testing records pioneered by Kaiser Permanente founding physician Morris Collen, MD, who is widely regarded worldwide as a health care informatics pioneer. Of the original 9,844 participants, 598 were diagnosed with Alzheimer's disease or vascular dementia between 1994 and 2007, when the participants were between 61 and 88 years old.
This epidemiological study did not examine the mechanism of the link between cholesterol levels and dementia.
This study is part of an ongoing body of research at Kaiser Permanente to better understand the risk and protective factors for dementia. Dr. Whitmer recently authored two dementia-related studies: one that found a larger abdomen in midlife increases risk of late-life dementia, and one that showed that low blood sugar events in elderly patients with type 2 diabetes increase their risk for dementia. Another Kaiser Permanente study, led by Valerie Crooks of Kaiser Permanente in Southern California, found that having a strong social network of friends and family appears to decrease risk for dementia.
Largest, longest study shows even moderately elevated cholesterol level boosts dementia risk
Elevated cholesterol levels in midlife – even levels considered only borderline elevated – significantly increase the risk of Alzheimer's disease and vascular dementia later in life, according to a new study by researchers at Kaiser Permanente's Division of Research and the University of Kuopio in Finland. The study appears in the journal Dementia & Geriatric Cognitive Disorders.
The four-decade study of 9,844 men and women found that having high cholesterol in midlife (240 or higher milligrams per deciliter of blood) increases, by 66 percent, the risk for Alzheimer's disease later in life. Even borderline cholesterol levels (200 – 239 mg/dL) in midlife raised risk for late-life vascular dementia by nearly the same amount: 52 percent. Vascular dementia, the second most common form of dementia after Alzheimer's disease, is a group of dementia syndromes caused by conditions affecting the blood supply to the brain. Scientists are still trying to pinpoint the genetic factors and lifestyle causes for Alzheimer's disease.
By measuring cholesterol levels in 1964 to 1973 based on the 2002 Adult Treatment Panel III guidelines (the current practice standard) when the Kaiser Permanente Northern California members were 40 to 45 years old, then following the participants for 40 years, this study is the largest long-term study with the most diverse population to examine the midlife cholesterol levels and late-life dementia. It is also the first study to look at borderline high cholesterol levels and vascular dementia, rather than just Alzheimer's disease.
"Our study shows that even moderately high cholesterol levels in your 40s puts people at greater risk for Alzheimer's disease and vascular dementia decades later," said the study's senior author. Rachel Whitmer, Ph.D., a research scientist and epidemiologist at the Kaiser Permanente Division of Research in Oakland, Calif. "Considering that nearly 100 million Americans have either high or borderline cholesterol levels, this is a disturbing finding. The good news here is that what is good for the heart is also good for the mind, and this is an early risk factor for dementia that can be modified and managed by lowering cholesterol through healthy lifestyle changes."
This study, funded by the National Institutes of Health, adds to other research emphasizing the importance of addressing dementia risk factors in midlife, before an underlying disease or symptoms appear, the researchers said.
"Our findings add to the existing body of evidence on a degree of overlap between two dementia types in terms of risk factors, symptoms and neuropathology," said the study's lead author, Alina Solomon, MD, a researcher with the Department of Neurology at the University of Kuopio, Finland. "Dementia and cardiovascular disease are common major health problems, share several risk factors and often occur simultaneously, interacting with one another. A holistic approach that addresses multiple major health problems simultaneously is needed to effectively manage these disorders."
The study tracked members of Kaiser Permanente's Northern California Medical Group from 1967 to 2007 by using the multiphasic testing records pioneered by Kaiser Permanente founding physician Morris Collen, MD, who is widely regarded worldwide as a health care informatics pioneer. Of the original 9,844 participants, 598 were diagnosed with Alzheimer's disease or vascular dementia between 1994 and 2007, when the participants were between 61 and 88 years old.
This epidemiological study did not examine the mechanism of the link between cholesterol levels and dementia.
This study is part of an ongoing body of research at Kaiser Permanente to better understand the risk and protective factors for dementia. Dr. Whitmer recently authored two dementia-related studies: one that found a larger abdomen in midlife increases risk of late-life dementia, and one that showed that low blood sugar events in elderly patients with type 2 diabetes increase their risk for dementia. Another Kaiser Permanente study, led by Valerie Crooks of Kaiser Permanente in Southern California, found that having a strong social network of friends and family appears to decrease risk for dementia.
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