Two new vitamin D studies using a sophisticated form of analysis called meta-analysis, in which data from multiple reports is combined, have revealed new prescriptions for possibly preventing up to half of the cases of breast cancer and two-thirds of the cases of colorectal cancer in the United States. The work was conducted by a core team of cancer prevention specialists at the Moores Cancer Center at University of California, San Diego (UCSD), and colleagues from both coasts.
The breast cancer study, published online in the current issue of the Journal of Steroid Biochemistry and Molecular Biology, pooled dose-response data from two earlier studies - the Harvard Nurses Health Study and the St. George's Hospital Study - and found that individuals with the highest blood levels of 25-hydroxyvitamin D, or 25(OH)D, had the lowest risk of breast cancer.
The researchers divided the 1,760 records of individuals in the two studies into five equal groups, from the lowest blood levels of 25(OH)D (less than 13 nanograms per milliliter, or 13 ng/ml) to the highest (approximately 52 ng/ml). The data also included whether or not the individual had developed cancer.
"The data were very clear, showing that individuals in the group with the lowest blood levels had the highest rates of breast cancer, and the breast cancer rates dropped as the blood levels of 25-hydroxyvitamin D increased," said study co-author Cedric Garland, Dr.P.H. "The serum level associated with a 50 percent reduction in risk could be maintained by taking 2,000 international units of vitamin D3 daily plus, when the weather permits, spending 10 to 15 minutes a day in the sun."
The colorectal cancer study, published online February 6 in the American Journal of Preventive Medicine, is a meta-analysis of five studies that explored the association of blood levels of 25(OH)D with risk of colon cancer. All of the studies involved blood collected and tested for 25 (OH)D levels from healthy volunteer donors who were then followed for up to 25 years for development of colorectal cancer.
As with the breast cancer study, the dose-response data on a total of 1,448 individuals were put into order by serum 25(OH)D level and then divided into five equal groups, from the lowest blood levels to the highest.
"Through this meta-analysis we found that raising the serum level of 25-hydroxyvitamin D to 34 ng/ml would reduce the incidence rates of colorectal cancer by half," said co-author Edward D. Gorham, Ph.D. "We project a two-thirds reduction in incidence with serum levels of 46ng/ml, which corresponds to a daily intake of 2,000 IU of vitamin D3. This would be best achieved with a combination of diet, supplements and 10 to 15 minutes per day in the sun."
Vitamin D3 is available through diet, supplements and exposure of the skin to sunlight, or ultraviolet B (UVB). In the paper, the researchers underscored the importance of limiting sun exposure such that the skin does not change color (tan) or burn. For a typical fair-skinned Caucasian individual, adequate vitamin D could be photosynthesized safely by spending 10 to 15 minutes in the noontime sun on a clear day with 50 percent of skin area exposed to the sun. Darker skinned individuals may require more time in the sun, such as 25 minutes. For people with photosensitivity disorders, or anyone with a personal or family history of nonmelanoma skin cancer, any amount of extra sun exposure would be inadvisable.
A larger daily dose of vitamin D could reduce the incidence of colorectal cancer with minimal risk, according to a new review that pools results from five studies.
The analysis found that maintaining a specific target blood level of vitamin D was associated with a 50 percent lower risk of colorectal cancer than that seen in people with consistently lower blood levels.
Previous studies had shown that lower blood levels of vitamin D did not protect against colorectal cancer, according to lead author Edward Gorham, Ph.D., a research epidemiologist with the Naval Health Research Center in San Diego. However, a meta-analysis pools the data from several studies, thus increasing the strength of the results.
The study is being published in the March issue of the American Journal of Preventive Medicine.
The five studies looked at serum collected from healthy volunteers who were then followed for periods ranging from two years to 25 years. There were 535 cases in the pooled analysis and 913 controls, or 1,448 total participants.
The researchers found that a blood serum vitamin D level of 33 nanograms per milliliter or higher was associated with a 50 percent lower risk of colorectal cancer than that seen with blood levels of 12 nanograms per milliliter or lower.
Vitamin D levels in the body are a factor of both diet and sun exposure. Exposing the skin to the sun lets the body synthesize vitamin D, which is why mortality due to colorectal cancer may be higher in geographic areas that get less sunshine.
The amount of dietary vitamin D needed to reach the serum levels that appear to be protective against colorectal cancer — 1,000 to 2,000 international units a day — would not pose any risk, according to Gorham: “The Institute of Medicine has set a ‘No Adverse Effect Level’ of 2,000 IU per day for vitamin D intake, so this recommendation would be safe for most people.”
There is no official recommended dietary allowance for vitamin D, but an adequate dietary intake per day for most adults is currently considered to be 200 to 400 IU.
Small amounts of sun exposure would also help people boost their vitamin D levels. Fifteen to 20 minutes per day without sunscreen is enough for the body to synthesize 10,000 IU of vitamin D with minimal risk of sunburn or skin cancer, Gorham said.
“The results are pretty straightforward,” said Karen Glanz, Ph.D., director of Emory University’s Prevention Research Center at the Rollins School of Public Health. However, changing behavior on the basis of this study may be premature, she said. The analysis found an association between vitamin D levels and lowered risk, not a definite link, Glanz said, but adding vitamin D to the diet or taking a supplement would probably not do much harm and there could be a benefit.
The meta-analysis on colorectal cancer includes data from the Women's Health Initiative, which had shown in 2006 that a low dose of vitamin D did not protect against colorectal cancer within seven years of follow-up. However, the researchers wrote, the meta-analysis indicates that a higher dose may reduce its incidence.
"Meta-analysis is an important tool for revealing trends that may not be apparent in a single study," said co-author Sharif B. Mohr, M.P.H. "Pooling of independent but similar studies increases precision, and therefore the confidence level of the findings."
Wednesday, February 7, 2007
Mind-set matters -- Why thinking you got a work out may actually make you healthier
As the commitment to our New Year's resolutions wanes and the trips to the gym become more infrequent, new findings appearing in the February issue of Psychological Science may offer us one more chance to reap the benefits of exercise through our daily routine. Harvard University psychologist Ellen Langer and her student Alia Crum found that many of the beneficial results of exercise are due to the placebo effect.
The surgeon general recommends 30 minutes of daily exercise to maintain a healthy lifestyle. While this may be harder for those who are required to sit behind a desk for eight hours, other jobs are inherently physical, like a hotel housekeeper. On average, they clean 15 rooms per day, each taking 20 to 30 minutes to complete. According to the study, the housekeepers might not perceive their job as exercise, but if their mind-set is shifted so that they become aware of the exercise they are getting, then health improvements would be expected to follow.
The researchers studied 84 female housekeepers from seven hotels. Women in 4 hotels were told that their regular work was enough exercise to meet the requirements for a healthy, active lifestyle, whereas the women in the other three hotels were told nothing. To determine if the placebo effect plays a role in the benefits of exercise, the researchers investigated whether subjects' mind-set (in this case, their perceived levels of exercise) could inhibit or enhance the health benefits of exercise independent of any actual exercise.
Four weeks later, the researchers returned to assess any changes in the women's health. They found that the women in the informed group had lost an average of 2 pounds, lowered their blood pressure by almost 10 percent, and were significantly healthier as measured by body-fat percentage, body mass index, and waist-to-hip ratio. These changes were significantly higher than those reported in the control group and were especially remarkable given the time period of only four weeks.
Langer writes, "Whether the change in physiological health was brought about directly or indirectly, it is clear that health is significantly affected by mind-set." This research shows the moderating role of mind-set and its ability to enhance health, which may have particular relevance for treating diseases associated with a sedentary lifestyle.
The surgeon general recommends 30 minutes of daily exercise to maintain a healthy lifestyle. While this may be harder for those who are required to sit behind a desk for eight hours, other jobs are inherently physical, like a hotel housekeeper. On average, they clean 15 rooms per day, each taking 20 to 30 minutes to complete. According to the study, the housekeepers might not perceive their job as exercise, but if their mind-set is shifted so that they become aware of the exercise they are getting, then health improvements would be expected to follow.
The researchers studied 84 female housekeepers from seven hotels. Women in 4 hotels were told that their regular work was enough exercise to meet the requirements for a healthy, active lifestyle, whereas the women in the other three hotels were told nothing. To determine if the placebo effect plays a role in the benefits of exercise, the researchers investigated whether subjects' mind-set (in this case, their perceived levels of exercise) could inhibit or enhance the health benefits of exercise independent of any actual exercise.
Four weeks later, the researchers returned to assess any changes in the women's health. They found that the women in the informed group had lost an average of 2 pounds, lowered their blood pressure by almost 10 percent, and were significantly healthier as measured by body-fat percentage, body mass index, and waist-to-hip ratio. These changes were significantly higher than those reported in the control group and were especially remarkable given the time period of only four weeks.
Langer writes, "Whether the change in physiological health was brought about directly or indirectly, it is clear that health is significantly affected by mind-set." This research shows the moderating role of mind-set and its ability to enhance health, which may have particular relevance for treating diseases associated with a sedentary lifestyle.
Children who sleep less more likely to be overweight
Research indicates that getting inadequate sleep has negative effects on children's social and emotional well-being and school performance. Now a Northwestern University study finds it also increases their risk of being overweight.
The study -- conducted in two waves of data collection approximately five years apart -- is the first nationally representative, longitudinal investigation of the relationship between sleep, Body Mass Index (BMI) and overweight status in children aged 3 to 18.
"Our study suggests that earlier bedtimes, later wake times and later school start times could be an important and relatively low-cost strategy to help reduce childhood weight problems," says Emily Snell. Snell is co-author of "Sleep and the Body Mass Index and Overweight Status of Children and Adolescents" in the Jan./Feb. issue of Child Development.
"We found even an hour of sleep makes a big difference in weight status," said Snell, a Northwestern doctoral student in human development and social policy. "Sleeping an additional hour reduced young children's chance of being overweight from 36 percent to 30 percent, while it reduced older children's risk from 34 percent to 30 percent."
The Northwestern study not only differs from most other investigations of the effects of sleep on children's weight in its five-year approach. It also helps disentangle the issue of whether sleep actually affects weight or whether children who already are overweight are simply poor sleepers. In addition, it takes into account the possible effects of other variables including race, ethnicity and income.
Snell co-wrote the article with Northwestern's Emma K. Adam and Greg J. Duncan, assistant professor and professor of education and social policy, respectively. Adam and Duncan are fellows at the University's Institute for Policy Research and Center for Social Disparities and Health.
Their findings also suggest that later bedtimes play a greater role in the overweight status of children aged from 3 to 8, while earlier wake times play a greater role in children aged 8 to 13. No significant differences in the effect of sleep on weight was found between boys and girls nor was there evidence that children who slept more grew more in height.
The researchers used time diaries, in which the parents or caregivers of young children or children old enough to keep diaries themselves recorded all activities -- including bedtime, time asleep and wake time -- over the course of a weekday and weekend day. In analyzing the diaries, they found troubling age-related trends in sleep behavior.
By age 7, children were sleeping on average less than 10 hours on weekdays. By age 14, weekday sleep time fell to 8.5 hours. A full 16 percent of adolescents aged 13 to 18 were found to sleep fewer than seven hours on weekday nights. The National Sleep Foundation recommends children aged 5 to 12 years get 10 to 11 hours of sleep and adolescents get eight to nine hours.
"Many American children are simply not getting the sleep they need. Parents, policymakers and health care providers all are concerned about the obesity epidemic among children," says Snell. "Our results suggest that something as simple as helping children sleep more at night could reduce their risk of being overweight."
The 2,182 children examined in the study came from a nationally representative sample called the Child Development Supplement of the Panel Survey of Income Dynamics.
The study -- conducted in two waves of data collection approximately five years apart -- is the first nationally representative, longitudinal investigation of the relationship between sleep, Body Mass Index (BMI) and overweight status in children aged 3 to 18.
"Our study suggests that earlier bedtimes, later wake times and later school start times could be an important and relatively low-cost strategy to help reduce childhood weight problems," says Emily Snell. Snell is co-author of "Sleep and the Body Mass Index and Overweight Status of Children and Adolescents" in the Jan./Feb. issue of Child Development.
"We found even an hour of sleep makes a big difference in weight status," said Snell, a Northwestern doctoral student in human development and social policy. "Sleeping an additional hour reduced young children's chance of being overweight from 36 percent to 30 percent, while it reduced older children's risk from 34 percent to 30 percent."
The Northwestern study not only differs from most other investigations of the effects of sleep on children's weight in its five-year approach. It also helps disentangle the issue of whether sleep actually affects weight or whether children who already are overweight are simply poor sleepers. In addition, it takes into account the possible effects of other variables including race, ethnicity and income.
Snell co-wrote the article with Northwestern's Emma K. Adam and Greg J. Duncan, assistant professor and professor of education and social policy, respectively. Adam and Duncan are fellows at the University's Institute for Policy Research and Center for Social Disparities and Health.
Their findings also suggest that later bedtimes play a greater role in the overweight status of children aged from 3 to 8, while earlier wake times play a greater role in children aged 8 to 13. No significant differences in the effect of sleep on weight was found between boys and girls nor was there evidence that children who slept more grew more in height.
The researchers used time diaries, in which the parents or caregivers of young children or children old enough to keep diaries themselves recorded all activities -- including bedtime, time asleep and wake time -- over the course of a weekday and weekend day. In analyzing the diaries, they found troubling age-related trends in sleep behavior.
By age 7, children were sleeping on average less than 10 hours on weekdays. By age 14, weekday sleep time fell to 8.5 hours. A full 16 percent of adolescents aged 13 to 18 were found to sleep fewer than seven hours on weekday nights. The National Sleep Foundation recommends children aged 5 to 12 years get 10 to 11 hours of sleep and adolescents get eight to nine hours.
"Many American children are simply not getting the sleep they need. Parents, policymakers and health care providers all are concerned about the obesity epidemic among children," says Snell. "Our results suggest that something as simple as helping children sleep more at night could reduce their risk of being overweight."
The 2,182 children examined in the study came from a nationally representative sample called the Child Development Supplement of the Panel Survey of Income Dynamics.
Monday, February 5, 2007
Sedentary teens more likely to have higher blood pressure
Teenagers who spend a lot of time planted in front of the TV are more likely to have higher blood pressure, regardless of whether they are overweight. "This is the first research to show a direct and independent connection between TV watching and higher blood pressure among adolescents," said study leader Nicolas Stettler, M.D., M.S.C.E., a pediatric nutrition specialist at The Children's Hospital of Philadelphia.
The team reported on their study of 4,500 American adolescents in the February issue of the Journal of Adolescent Health. They found that sedentary activities and higher body mass index (BMI) were associated with higher systolic blood pressure. Systolic blood pressure is the pressure found when the heart pumps, in contrast to diastolic blood pressure, the pressure between heart beats.
"It was already known that physical activity lowers blood pressure in both adults and children, but sedentary activity is not just the opposite of physical activity," said Dr. Stettler. "For example, other studies have found that decreasing sedentary activity in young people helps prevent or treat obesity better than interventions to increase physical activity."
If further studies confirm these results, encouraging adolescents to reduce their sedentary activity may improve their blood pressure and lower their later risk of cardiovascular disease and stroke.
The researchers studied nationally representative data from 4,500 U.S. adolescents, aged 12 to 19, who participated in the 1999-2002 National Health and Nutrition Examination Survey. Interviewers assessed the adolescents' nutritional intake and activities. Measurements of blood pressure and BMI were adjusted for gender and age.
Within the 12- to 15-year-old age group, the study team found higher blood pressure to be especially associated with higher levels of watching television and video. "Although the association between sedentary activity and systolic blood pressure was rather small, most adolescents spend several hours per day in sedentary activities," said Yasuki Kobayashi, M.D., Ph.D., of the University of Tokyo Department of Public Health, a co-author on this study. "Interventions to decrease sedentary activities may have an important public health impact."
"Elevated blood pressure is one of the most important risk factors for cardiovascular diseases and stroke," said Mr. Takehiro Sugiyama, a medical student at the University of Tokyo and first author on this study. "High blood pressure in adolescents is predictive of hypertension in adulthood, and in addition, adolescent obesity is a predictor or obesity and cardiovascular risk factors in young adulthood and beyond."
The researchers also found that higher BMI is associated with lower diastolic blood pressure, contrary to associations found previously in studies of adults. The implications of this finding are unclear, but shows that adolescents are not just "small adults" and may have determinants of blood pressure that are different from adults said the authors.
The team reported on their study of 4,500 American adolescents in the February issue of the Journal of Adolescent Health. They found that sedentary activities and higher body mass index (BMI) were associated with higher systolic blood pressure. Systolic blood pressure is the pressure found when the heart pumps, in contrast to diastolic blood pressure, the pressure between heart beats.
"It was already known that physical activity lowers blood pressure in both adults and children, but sedentary activity is not just the opposite of physical activity," said Dr. Stettler. "For example, other studies have found that decreasing sedentary activity in young people helps prevent or treat obesity better than interventions to increase physical activity."
If further studies confirm these results, encouraging adolescents to reduce their sedentary activity may improve their blood pressure and lower their later risk of cardiovascular disease and stroke.
The researchers studied nationally representative data from 4,500 U.S. adolescents, aged 12 to 19, who participated in the 1999-2002 National Health and Nutrition Examination Survey. Interviewers assessed the adolescents' nutritional intake and activities. Measurements of blood pressure and BMI were adjusted for gender and age.
Within the 12- to 15-year-old age group, the study team found higher blood pressure to be especially associated with higher levels of watching television and video. "Although the association between sedentary activity and systolic blood pressure was rather small, most adolescents spend several hours per day in sedentary activities," said Yasuki Kobayashi, M.D., Ph.D., of the University of Tokyo Department of Public Health, a co-author on this study. "Interventions to decrease sedentary activities may have an important public health impact."
"Elevated blood pressure is one of the most important risk factors for cardiovascular diseases and stroke," said Mr. Takehiro Sugiyama, a medical student at the University of Tokyo and first author on this study. "High blood pressure in adolescents is predictive of hypertension in adulthood, and in addition, adolescent obesity is a predictor or obesity and cardiovascular risk factors in young adulthood and beyond."
The researchers also found that higher BMI is associated with lower diastolic blood pressure, contrary to associations found previously in studies of adults. The implications of this finding are unclear, but shows that adolescents are not just "small adults" and may have determinants of blood pressure that are different from adults said the authors.
Parents blind to their children's weight
Researchers with Deakin's Centre for Physical Activity and Nutrition Research surveyed more than 1200 families to find out if parents had concerns about their children's weight and if they took any preventative action to avoid obesity in their children.
The study of more than 1100 families found that 89 per cent of parents of overweight 5—6 year-olds and 63 per cent of parents of overweight 10—12 year-olds were unaware their child was overweight. It also revealed that 71 per cent of parents of overweight 5—6 year-olds and 43 per cent of parents with overweight 10—12 year-olds did not think their child's weight was a problem.
"These are quite troubling results and suggest that current obesity prevention campaigns are not hitting the mark with parents," said head of the Centre, Professor David Crawford.
"Parents are part of the front line in the battle to reverse the trend of obesity in children, it is therefore essential that they are armed with information and practical strategies that they understand and can easily build into their daily lives."
Professor Crawford said it was not altogether surprising that many parents were unaware their child was overweight given that "many adults are not able to recognise overweight in themselves."
He suggested that some reasons for the lack of recognition of childhood overweight could be that some parents, particularly mothers, tend to judge overweight by whether or not their child is teased about their weight at school or has developed limitations in physical activity; or that, with childhood obesity becoming increasingly normative, that some excess weight simply goes unnoticed.
Despite parents' inability to recognise problem weight in their children, Professor Crawford said a substantial proportion of parents reported they employed various strategies to help prevent their child from gaining too much weight.
The most common strategies included: promoting a balanced diet; promoting physical activity; reducing junk food; limiting the amount of fat and sugar; promoting more fruit.
While this is encouraging, Professor Crawford said that less than 10 per cent of parents increased consumption of fruit and vegetables as a potential weight-control strategy, and few reported that they tried to limit or reduce their child's intake of high-energy drinks and limit television viewing.
The study of more than 1100 families found that 89 per cent of parents of overweight 5—6 year-olds and 63 per cent of parents of overweight 10—12 year-olds were unaware their child was overweight. It also revealed that 71 per cent of parents of overweight 5—6 year-olds and 43 per cent of parents with overweight 10—12 year-olds did not think their child's weight was a problem.
"These are quite troubling results and suggest that current obesity prevention campaigns are not hitting the mark with parents," said head of the Centre, Professor David Crawford.
"Parents are part of the front line in the battle to reverse the trend of obesity in children, it is therefore essential that they are armed with information and practical strategies that they understand and can easily build into their daily lives."
Professor Crawford said it was not altogether surprising that many parents were unaware their child was overweight given that "many adults are not able to recognise overweight in themselves."
He suggested that some reasons for the lack of recognition of childhood overweight could be that some parents, particularly mothers, tend to judge overweight by whether or not their child is teased about their weight at school or has developed limitations in physical activity; or that, with childhood obesity becoming increasingly normative, that some excess weight simply goes unnoticed.
Despite parents' inability to recognise problem weight in their children, Professor Crawford said a substantial proportion of parents reported they employed various strategies to help prevent their child from gaining too much weight.
The most common strategies included: promoting a balanced diet; promoting physical activity; reducing junk food; limiting the amount of fat and sugar; promoting more fruit.
While this is encouraging, Professor Crawford said that less than 10 per cent of parents increased consumption of fruit and vegetables as a potential weight-control strategy, and few reported that they tried to limit or reduce their child's intake of high-energy drinks and limit television viewing.
Thursday, February 1, 2007
18 million men in the United States affected by erectile dysfunction
Lifestyle changes could improve male sexual function
More than 18 million men in the United States over age 20 are affected by erectile dysfunction, according to a study by researchers from the Johns Hopkins Bloomberg School of Public Health. The prevalence of erectile dysfunction was strongly linked with age, cardiovascular disease, diabetes and a lack of physical activity. The findings also indicate that lifestyle changes, such as increased physical activity and measures to prevent cardiovascular disease and diabetes, may also prevent decreased erectile function. The study is published in the February 1, 2007, issue of the American Journal of Medicine.
"Physicians should be aggressive in screening and managing middle-aged and older patients for erectile dysfunction, especially among patients with diabetes or hypertension," said Elizabeth Selvin, PhD, MPH, lead author of the study and a faculty member in the Bloomberg School of Public Health's Department of Epidemiology. "The associations of erectile dysfunction with diabetes and cardiovascular risk factors may serve as powerful motivators for men who need to make changes in their diet and lifestyle."
For the study, the research team analyzed data from 2,126 men who participated in the National Health and Nutrition Examination Survey (NHANES). Men who reported being "sometimes able" or "never able" to get and keep an erection were categorized as having erectile dysfunction, while men who reported being "always or almost always able" or "usually able" were not.
The overall prevalence of erectile dysfunction among men in the United States was 18 percent. Men aged 70 and older were much more likely to report having erectile dysfunction compared to only 5 percent in men between the ages of 20 and 40. Nearly half of all men in the study with diabetes also had erectile dysfunction. And, almost 90 percent of all men with erectile dysfunction had at least one risk factor for cardiovascular disease, including diabetes, hypertension, having poor cholesterol levels or being a current smoker. Men with erectile dysfunction were also less likely to have engaged in vigorous physical activity within the month prior to participation in the study.
More than 18 million men in the United States over age 20 are affected by erectile dysfunction, according to a study by researchers from the Johns Hopkins Bloomberg School of Public Health. The prevalence of erectile dysfunction was strongly linked with age, cardiovascular disease, diabetes and a lack of physical activity. The findings also indicate that lifestyle changes, such as increased physical activity and measures to prevent cardiovascular disease and diabetes, may also prevent decreased erectile function. The study is published in the February 1, 2007, issue of the American Journal of Medicine.
"Physicians should be aggressive in screening and managing middle-aged and older patients for erectile dysfunction, especially among patients with diabetes or hypertension," said Elizabeth Selvin, PhD, MPH, lead author of the study and a faculty member in the Bloomberg School of Public Health's Department of Epidemiology. "The associations of erectile dysfunction with diabetes and cardiovascular risk factors may serve as powerful motivators for men who need to make changes in their diet and lifestyle."
For the study, the research team analyzed data from 2,126 men who participated in the National Health and Nutrition Examination Survey (NHANES). Men who reported being "sometimes able" or "never able" to get and keep an erection were categorized as having erectile dysfunction, while men who reported being "always or almost always able" or "usually able" were not.
The overall prevalence of erectile dysfunction among men in the United States was 18 percent. Men aged 70 and older were much more likely to report having erectile dysfunction compared to only 5 percent in men between the ages of 20 and 40. Nearly half of all men in the study with diabetes also had erectile dysfunction. And, almost 90 percent of all men with erectile dysfunction had at least one risk factor for cardiovascular disease, including diabetes, hypertension, having poor cholesterol levels or being a current smoker. Men with erectile dysfunction were also less likely to have engaged in vigorous physical activity within the month prior to participation in the study.
Calcium lowers cardiovascular risk in people on a weight loss program
Researchers have discovered that taking calcium and vitamin D supplements while on a weight loss program lowers the risk of cardiovascular disease.
The scientists enrolled 63 women with a body mass index over 30 on a 15-week low-calorie diet. At the start of the experiment, the women's daily calcium intake was 700 mg on average, well below the 1,000 mg recommendation. "This is nothing exceptional," points out Dr. Angelo Tremblay, who led the study. "More than 50% of women don't get the daily recommended dose."
In addition to the low-calorie diet, participants were given daily tablets containing either a placebo or 1,200 mg of calcium with vitamin D "to facilitate calcium absorption," adds Dr. Tremblay. At the end of the 15-week period, researchers observed greater drops in LDL (bad cholesterol) and increases in HDL (good cholesterol) in the calcium-plus-vitamin D group than in the placebo group.
Researchers also observed that the amount of weight lost during the 15 weeks did not seem to have an impact on the improvement seen in cholesterol levels. This suggests that calcium and vitamin D supplementation might also lower cardiovascular risk in women with low calcium intake as it does with women on a diet.
The authors conclude that prescribing calcium and vitamin D supplements should be considered as a component of weight loss programs aimed at people with insufficient calcium intake.
Professor Tremblay and his team have been studying the relationship between calcium and obesity for the past six years. Their first results, published in 2003, revealed that people with low calcium intake have a higher fat percentage, wider waists, and higher bad cholesterol levels than people whose calcium intake is moderate or sufficient. A second study, spanning over six years, showed that people who reduced their dairy consumption during that period gained weight, and saw an increase in body fat percentage and waist size.
The scientists enrolled 63 women with a body mass index over 30 on a 15-week low-calorie diet. At the start of the experiment, the women's daily calcium intake was 700 mg on average, well below the 1,000 mg recommendation. "This is nothing exceptional," points out Dr. Angelo Tremblay, who led the study. "More than 50% of women don't get the daily recommended dose."
In addition to the low-calorie diet, participants were given daily tablets containing either a placebo or 1,200 mg of calcium with vitamin D "to facilitate calcium absorption," adds Dr. Tremblay. At the end of the 15-week period, researchers observed greater drops in LDL (bad cholesterol) and increases in HDL (good cholesterol) in the calcium-plus-vitamin D group than in the placebo group.
Researchers also observed that the amount of weight lost during the 15 weeks did not seem to have an impact on the improvement seen in cholesterol levels. This suggests that calcium and vitamin D supplementation might also lower cardiovascular risk in women with low calcium intake as it does with women on a diet.
The authors conclude that prescribing calcium and vitamin D supplements should be considered as a component of weight loss programs aimed at people with insufficient calcium intake.
Professor Tremblay and his team have been studying the relationship between calcium and obesity for the past six years. Their first results, published in 2003, revealed that people with low calcium intake have a higher fat percentage, wider waists, and higher bad cholesterol levels than people whose calcium intake is moderate or sufficient. A second study, spanning over six years, showed that people who reduced their dairy consumption during that period gained weight, and saw an increase in body fat percentage and waist size.
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