New study indicates that people may need more dietary choline than previously thought
Eggs one of the best sources of the nutrient
A new study published in the May issue of the American Journal of Clinical Nutrition indicates that the current recommended Adequate Intake (AI) for choline may, in fact, be inadequate for some people. Choline is an essential nutrient for normal functioning of all cells, including those involved with liver metabolism, brain and nerve function, memory, and the transportation of nutrients throughout the body.
In this depletion-repletion study, 57 adult subjects (26 men, 16 premenopausal women and 15 postmenopausal women) were fed a diet containing 550 mg of choline for 10 days, then fed less than 50 mg a day of choline for up to 42 days.
When deprived of the nutrient, 77 percent of men, 80 percent of postmenopausal women and 44 percent of premenopausal women developed fatty liver or muscle damage.
Six men (23 percent) developed these signs while consuming the initial 550 mg of daily choline, even though 550 mg is the current AI for men.
Nineteen percent of the subjects required as high as 825 mg of daily choline to prevent or reverse the organ dysfunction associated with the low-choline diet, an amount significantly higher than the current AI.
For all participants, blood homocysteine levels increased during choline depletion. Other studies have associated high homocysteine levels with heart disease.
"These study results clearly indicate that some adults, notably men and post-menopausal women, need more choline than is recommended by the current AI," says study co-author Kerry-Ann da Costa, PhD, a research assistant professor at the University of North Carolina at Chapel Hill. "We hope these findings will aid the Institute of Medicine in refining the Dietary Reference Intake (DRI) of this nutrient."
This study is the most complete study of choline requirements to date and is the first to include women. Its division of participants into two groups – one receiving dietary supplementation of folic acid and one not – also determined that susceptibility to choline deficiency was not altered by folic acid supplementation.
Closing the Choline Gap
Additional research on the population demonstrated that choline intake is far below the current AI, a concern that intakes may be too low to meet the needs of many individuals.
Research conducted at Iowa State University found that only 10 percent or less of older children, men, women and pregnant women in America get the AI of choline each day.
A separate study presented this month at the National Nutrient Data Bank Conference found that choline intake decreases with age and that adults ages 71 and older consume an average of about 264 milligrams per day – roughly half of the AI for choline.
Eggs, beef liver, chicken liver and wheat germ are considered excellent sources of choline. Two eggs contain 280 milligrams of choline, half the recommended daily supply.
"Eggs are a practical food that can help people get the choline they need, along with several other nutrients, at just 75 calories an egg," says registered dietitian Maye Musk. "Choline is actually found in the yolk of the egg, so people who consistently only eat egg whites may be missing out on a key nutrient opportunity."
Why Choline Matters
The importance of dietary choline has been well-established.
A 2004 study in the American Journal of Epidemiology linked poor dietary choline to adverse outcomes during pregnancy, including a four-fold increased risk of having a baby with a neural tube defect.
A research review published in the Annual Reviews of Nutrition suggests that choline plays an important role in normal fetal development, particularly during the stages that involve knowledge acquirement and life-long memory function.
Friday, May 25, 2007
Binge drinking= deficits among college students
Binge drinking leads to neurocognitive deficits among college students
Alcoholics tend to have poorer neurocognitive functioning, including decision-making capabilities.
A new study has found that binge drinking, common among college students, is associated with impaired decision making.
The long-term neurocognitive effects of binge drinking during young adulthood are unclear.
Researchers know that alcoholics tend to have poorer neurocognitive functioning, including decision making, than non-alcoholics do. Less is known, however, about alcohol’s effects on decision-making capabilities among people who drink heavily but are not considered alcoholics. A new study has found that binge drinking can lead to poor decision making among college students, independent of impulsivity.
Results are published in the June issue of Alcoholism: Clinical & Experimental Research.
"Alcoholics tend to exhibit poorer decision making such as preferring short-term rewards, when these are coupled to long-term losses, instead of choosing options which go together with long-term rewards," said Anna E. Goudriaan, a postdoctoral researcher at the University of Amsterdam and corresponding author for the study.
These choices tend to reflect more serious problems with executive functioning, added Jenny Larkins, a graduate student in clinical psychology at the University of Missouri. "Executive functioning involves skills such as planning for the future, abstract reasoning, inhibiting or delaying responses, initiating behavior, doing two things at once, and shifting between two activities in a flexible way," she said.
"There are not a lot of studies that focus on the effects of heavy alcohol use in people who are not addicted to alcohol," said Goudriaan. "However, it seemed logical … that heavy alcohol would impact their decision making, and we targeted young adults since they tend to drink the most, and binge drink the most. We specifically targeted binge drinking, since some animal studies suggest that it is deleterious for brain functioning."
Researchers examined 200 participants in an ongoing student-health study at the University of Missouri-Columbia. They formed four subgroups (n=50, 50% male) according to estimated binge-drinking trajectories during pre-college through to second year: low-binge drinkers; stable moderate-binge drinkers; increasing binge drinkers; and stable high-binge drinkers. Study authors also gathered decision-making and impulsivity measures, Iowa Gambling Task (IGT) results, and multiple indicators of heavy alcohol use.
Note: The Iowa Gambling Task is a computer card game in which four decks of cards are presented on the screen. The participant must choose a card from one of the four decks: each time they choose a card they will "win" money, but every so often, choosing a card will cause them to "lose" money. The goal of the game is to win as much money as possible. Decks A and B have a total penalty of $1250 for every ten cards; C and D have a total penalty of $250 for every ten cards). Thus, A and B are "bad decks," and C and D are "good decks."
"We found that stable high-binge drinking, starting at a pre-college age, is related to diminished decision-making abilities, as exemplified by preferring short-term rewards over long-term losses," said Goudriaan. "In other words, this study shows that even in a group of "healthy" college students who are not alcoholics, heavy alcohol use is related to diminished decision making abilities or disadvantageous cognitive functions."
"It is also interesting to note that neither externalizing psychopathology nor impulsivity as measured by questionnaires was associated with impaired IGT performance," observed Larkins. "However, this finding … should be tested in other college student samples as it could be due to the sampling strategy employed."
"Based on these results and those from several other studies," said Larkins, "adolescence appears to be a time of exquisite sensitivity to the effects of alcohol on the brain. For these reasons, parents and clinicians must be especially diligent in monitoring young people to prevent alcohol abuse, and further attention to treatment programs designed for adolescents is warranted."
Alcoholics tend to have poorer neurocognitive functioning, including decision-making capabilities.
A new study has found that binge drinking, common among college students, is associated with impaired decision making.
The long-term neurocognitive effects of binge drinking during young adulthood are unclear.
Researchers know that alcoholics tend to have poorer neurocognitive functioning, including decision making, than non-alcoholics do. Less is known, however, about alcohol’s effects on decision-making capabilities among people who drink heavily but are not considered alcoholics. A new study has found that binge drinking can lead to poor decision making among college students, independent of impulsivity.
Results are published in the June issue of Alcoholism: Clinical & Experimental Research.
"Alcoholics tend to exhibit poorer decision making such as preferring short-term rewards, when these are coupled to long-term losses, instead of choosing options which go together with long-term rewards," said Anna E. Goudriaan, a postdoctoral researcher at the University of Amsterdam and corresponding author for the study.
These choices tend to reflect more serious problems with executive functioning, added Jenny Larkins, a graduate student in clinical psychology at the University of Missouri. "Executive functioning involves skills such as planning for the future, abstract reasoning, inhibiting or delaying responses, initiating behavior, doing two things at once, and shifting between two activities in a flexible way," she said.
"There are not a lot of studies that focus on the effects of heavy alcohol use in people who are not addicted to alcohol," said Goudriaan. "However, it seemed logical … that heavy alcohol would impact their decision making, and we targeted young adults since they tend to drink the most, and binge drink the most. We specifically targeted binge drinking, since some animal studies suggest that it is deleterious for brain functioning."
Researchers examined 200 participants in an ongoing student-health study at the University of Missouri-Columbia. They formed four subgroups (n=50, 50% male) according to estimated binge-drinking trajectories during pre-college through to second year: low-binge drinkers; stable moderate-binge drinkers; increasing binge drinkers; and stable high-binge drinkers. Study authors also gathered decision-making and impulsivity measures, Iowa Gambling Task (IGT) results, and multiple indicators of heavy alcohol use.
Note: The Iowa Gambling Task is a computer card game in which four decks of cards are presented on the screen. The participant must choose a card from one of the four decks: each time they choose a card they will "win" money, but every so often, choosing a card will cause them to "lose" money. The goal of the game is to win as much money as possible. Decks A and B have a total penalty of $1250 for every ten cards; C and D have a total penalty of $250 for every ten cards). Thus, A and B are "bad decks," and C and D are "good decks."
"We found that stable high-binge drinking, starting at a pre-college age, is related to diminished decision-making abilities, as exemplified by preferring short-term rewards over long-term losses," said Goudriaan. "In other words, this study shows that even in a group of "healthy" college students who are not alcoholics, heavy alcohol use is related to diminished decision making abilities or disadvantageous cognitive functions."
"It is also interesting to note that neither externalizing psychopathology nor impulsivity as measured by questionnaires was associated with impaired IGT performance," observed Larkins. "However, this finding … should be tested in other college student samples as it could be due to the sampling strategy employed."
"Based on these results and those from several other studies," said Larkins, "adolescence appears to be a time of exquisite sensitivity to the effects of alcohol on the brain. For these reasons, parents and clinicians must be especially diligent in monitoring young people to prevent alcohol abuse, and further attention to treatment programs designed for adolescents is warranted."
Coffee consumption may lower blood uric acid levels
Coffee consumption may lower blood uric acid levels -- the precursor of gout
High uric acid levels in the blood are a precursor of gout, the most common inflammatory arthritis in adult men. It is believed that coffee and tea consumption may affect uric acid levels but only one study has been conducted to date. A new large-scale study published in the June 2007 issue of Arthritis Care & Research (http://www.interscience.wiley.com/journal/arthritiscare) examined the relationship between coffee, tea, caffeine intake, and uric acid levels and found that coffee consumption is associated with lower uric acid levels but that this appears to be due to components other than caffeine.
Coffee is one of the most widely consumed beverages in the world; more than 50 percent of Americans drink it at the average rate of 2 cups per day. Because of this widespread consumption, its potential effects have important implications for public and individual health. Led by Hyon K. Choi, of the University of British Columbia in Vancouver, Canada, the current study was based on the U.S. Third National Health and Nutrition Examination Survey, conducted between 1988 and 1994. It included over 14,000 men and women at least 20 years old who consented to a medical exam in which blood and urine specimens were obtained. Coffee and tea consumption were determined based on responses to a food questionnaire that assessed intake over the previous month. Researchers estimated the amount of caffeine per cup of coffee or tea using data from the U.S. Department of Agriculture.
The results showed that levels of uric acid in the blood significantly decreased with increasing coffee intake, but not with tea intake. In addition, there was no association between total caffeine intake from beverages and uric acid levels. These results were similar to those found in the only previous study on the topic, which was conducted in Japan. Interestingly, there was an association between decaffeinated coffee consumption and uric acid levels. "These findings suggest that components of coffee other than caffeine contribute to the observed inverse association between coffee intake and uric acid levels," the researchers state.
A recent study found that coffee was associated lower C peptide levels (a marker of insulin levels). The researchers in the current study suggest that because there is a strong relationship between insulin resistance and elevated uric acid levels, the decreased insulin levels associated with coffee consumption may lead to lower uric acid levels. Coffee is also a major source of chlorogenic acid, a strong antioxidant, which may improve insulin sensitivity. Chlorogenic acid also helps inhibit glucose absorption in the intestine; in another study decaffeinated coffee seemed to delay intestinal absorption of glucose and increase concentrations of glucagon-like peptide 1, which is well known for its beneficial effects on insulin secretion and action. The researchers note further that their results could be due to an effect of non-caffeine components found in coffee, which would also explain why coffee affected uric acid levels but tea did not.
To examine how coffee consumption might aggravate or protect against this common and excruciatingly painful condition, researchers at the Arthritis Research Centre of Canada, University of British Columbia in Canada, Brigham and Women’s Hospital, Harvard Medical School, and Harvard School of Public Health in Boston conducted a prospective study on 45,869 men over age 40 with no history of gout at baseline. Over 12 years of follow-up, Hyon K. Choi, MD, DrPH, and his associates evaluated the relationship between the intake of coffee and the incidence of gout in this high risk population. Their findings, featured in the June 2007 issue of Arthritis & Rheumatism (http://www.interscience.wiley.com/journal/arthritis), provide compelling evidence that drinking 4 or more cups of coffee a day dramatically reduces the risk of gout for men.
Subjects were drawn from an ongoing study of some 50,000 male health professionals, 91 percent white, who were between 40 and 75 years of age in 1986 when the project was initiated. To assess coffee and total caffeine intake, Dr. Choi and his team used a food-frequency questionnaire, updated every 4 years. Participants chose from 9 frequency responses – ranging from never to 2 to 4 cups per week to 6 or more per day – to record their average consumption of coffee, decaffeinated coffee, tea, and other caffeine-containing comestibles, such as cola and chocolate.
Through another questionnaire, the researchers documented 757 newly diagnosed cases meeting the American College of Rheumatology criteria for gout during the follow-up period. Then, they determined the relative risk of incident gout for long-term coffee drinkers divided into 4 groups – less than 1 cup per day, 1 to 3 cups per day, 4 to 5 cups per day, and 6 or more cups per day – as well as for regular drinkers of decaffeinated coffee, tea, and other caffeinated beverages. They also evaluated the impact of other risk factors for gout – body mass index, history of hypertension, alcohol use, and a diet high in red meat and high-fat dairy foods among them – on the association between coffee consumption and gout among the study participants.
Most significantly, the data revealed that the risk for developing gout decreased with increasing coffee consumption. The risk of gout was 40 percent lower for men who drank 4 to 5 cups a day and 59 percent lower for men who drank 6 or more cups a day than for men who never drank coffee. There was also a modest inverse association with decaffeinated coffee consumption. These findings were independent of all other risk factors for gout. Tea drinking and total caffeine intake were both shown to have no effect on the incidence of gout among the subjects. On the mechanism of these findings, Dr. Choi speculates that components of coffee other than caffeine may be responsible for the beverage’s gout-prevention benefits. Among the possibilities, coffee contains the phenol chlorogenic acid, a strong antioxidant.
While not prescribing 4 or more cups a day, this study can help individuals make an informed choice regarding coffee consumption. "Our findings are most directly generalizable to men age 40 years and older, the most gout-prevalent population, with no history of gout," Dr. Choi notes. "Given the potential influence of female hormones on the risk of gout in women and an increased role of dietary impact on uric acid levels among patients with existing gout, prospective studies of these populations would be valuable."
High uric acid levels in the blood are a precursor of gout, the most common inflammatory arthritis in adult men. It is believed that coffee and tea consumption may affect uric acid levels but only one study has been conducted to date. A new large-scale study published in the June 2007 issue of Arthritis Care & Research (http://www.interscience.wiley.com/journal/arthritiscare) examined the relationship between coffee, tea, caffeine intake, and uric acid levels and found that coffee consumption is associated with lower uric acid levels but that this appears to be due to components other than caffeine.
Coffee is one of the most widely consumed beverages in the world; more than 50 percent of Americans drink it at the average rate of 2 cups per day. Because of this widespread consumption, its potential effects have important implications for public and individual health. Led by Hyon K. Choi, of the University of British Columbia in Vancouver, Canada, the current study was based on the U.S. Third National Health and Nutrition Examination Survey, conducted between 1988 and 1994. It included over 14,000 men and women at least 20 years old who consented to a medical exam in which blood and urine specimens were obtained. Coffee and tea consumption were determined based on responses to a food questionnaire that assessed intake over the previous month. Researchers estimated the amount of caffeine per cup of coffee or tea using data from the U.S. Department of Agriculture.
The results showed that levels of uric acid in the blood significantly decreased with increasing coffee intake, but not with tea intake. In addition, there was no association between total caffeine intake from beverages and uric acid levels. These results were similar to those found in the only previous study on the topic, which was conducted in Japan. Interestingly, there was an association between decaffeinated coffee consumption and uric acid levels. "These findings suggest that components of coffee other than caffeine contribute to the observed inverse association between coffee intake and uric acid levels," the researchers state.
A recent study found that coffee was associated lower C peptide levels (a marker of insulin levels). The researchers in the current study suggest that because there is a strong relationship between insulin resistance and elevated uric acid levels, the decreased insulin levels associated with coffee consumption may lead to lower uric acid levels. Coffee is also a major source of chlorogenic acid, a strong antioxidant, which may improve insulin sensitivity. Chlorogenic acid also helps inhibit glucose absorption in the intestine; in another study decaffeinated coffee seemed to delay intestinal absorption of glucose and increase concentrations of glucagon-like peptide 1, which is well known for its beneficial effects on insulin secretion and action. The researchers note further that their results could be due to an effect of non-caffeine components found in coffee, which would also explain why coffee affected uric acid levels but tea did not.
To examine how coffee consumption might aggravate or protect against this common and excruciatingly painful condition, researchers at the Arthritis Research Centre of Canada, University of British Columbia in Canada, Brigham and Women’s Hospital, Harvard Medical School, and Harvard School of Public Health in Boston conducted a prospective study on 45,869 men over age 40 with no history of gout at baseline. Over 12 years of follow-up, Hyon K. Choi, MD, DrPH, and his associates evaluated the relationship between the intake of coffee and the incidence of gout in this high risk population. Their findings, featured in the June 2007 issue of Arthritis & Rheumatism (http://www.interscience.wiley.com/journal/arthritis), provide compelling evidence that drinking 4 or more cups of coffee a day dramatically reduces the risk of gout for men.
Subjects were drawn from an ongoing study of some 50,000 male health professionals, 91 percent white, who were between 40 and 75 years of age in 1986 when the project was initiated. To assess coffee and total caffeine intake, Dr. Choi and his team used a food-frequency questionnaire, updated every 4 years. Participants chose from 9 frequency responses – ranging from never to 2 to 4 cups per week to 6 or more per day – to record their average consumption of coffee, decaffeinated coffee, tea, and other caffeine-containing comestibles, such as cola and chocolate.
Through another questionnaire, the researchers documented 757 newly diagnosed cases meeting the American College of Rheumatology criteria for gout during the follow-up period. Then, they determined the relative risk of incident gout for long-term coffee drinkers divided into 4 groups – less than 1 cup per day, 1 to 3 cups per day, 4 to 5 cups per day, and 6 or more cups per day – as well as for regular drinkers of decaffeinated coffee, tea, and other caffeinated beverages. They also evaluated the impact of other risk factors for gout – body mass index, history of hypertension, alcohol use, and a diet high in red meat and high-fat dairy foods among them – on the association between coffee consumption and gout among the study participants.
Most significantly, the data revealed that the risk for developing gout decreased with increasing coffee consumption. The risk of gout was 40 percent lower for men who drank 4 to 5 cups a day and 59 percent lower for men who drank 6 or more cups a day than for men who never drank coffee. There was also a modest inverse association with decaffeinated coffee consumption. These findings were independent of all other risk factors for gout. Tea drinking and total caffeine intake were both shown to have no effect on the incidence of gout among the subjects. On the mechanism of these findings, Dr. Choi speculates that components of coffee other than caffeine may be responsible for the beverage’s gout-prevention benefits. Among the possibilities, coffee contains the phenol chlorogenic acid, a strong antioxidant.
While not prescribing 4 or more cups a day, this study can help individuals make an informed choice regarding coffee consumption. "Our findings are most directly generalizable to men age 40 years and older, the most gout-prevalent population, with no history of gout," Dr. Choi notes. "Given the potential influence of female hormones on the risk of gout in women and an increased role of dietary impact on uric acid levels among patients with existing gout, prospective studies of these populations would be valuable."
Friday, May 18, 2007
Prostate Cancer: Beta-carotene Makes Worse
No magic tomato? Study breaks link between lycopene and prostate cancer prevention
Tomatoes might be nutritious and tasty, but don’t count on them to prevent prostate cancer. In the May issue of Cancer Epidemiology, Biomarkers & Prevention, researchers based at the National Cancer Institute and Fred Hutchinson Cancer Research Center report that lycopene, an antioxidant predominately found in tomatoes, does not effectively prevent prostate cancer. In fact, the researchers noted an association between beta-carotene, an antioxidant related to lycopene, and an increased risk for aggressive prostate cancer.
According to the researchers, the study is one of the largest to evaluate the role of blood concentrations of lycopene and other carotenoid antioxidants in preventing prostate cancer. Study data were derived from over 28,000 men enrolled in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, an ongoing, randomized National Cancer Institute trial to evaluate cancer screening methods and to investigate early markers of cancer.
"It is disappointing, since lycopene might have offered a simple and inexpensive way to lower prostate cancer risk for men concerned about this common disease," said Ulrike Peters, Ph.D., M.P.H., of the Fred Hutchinson Cancer Research Center. "Unfortunately, this easy answer just does not work."
Previous studies suggested that a diet rich in lycopene protected against prostate cancer, spurring commercial and public interest in the antioxidant. Antioxidants protect against free radicals, highly reactive atoms and molecules that can damage DNA and other important molecules in the cell. Since free radical damage increases with age, there has been a long-held suspicion in the scientific community that free radical damage could increase the risk of prostate cancer, a disease that has been clearly associated with age.
Subsequent studies of the potentially protective role of lycopene have been contradictory or inconclusive, according to Peters. In a 2006 study, she and her colleagues looked at the dietary intake of more than 25 tomato-based foods, also using data from the PLCO trial, and found no overall association between lycopene intake and prostate cancer.
In their current study, the researchers followed over 28,000 men between the ages of 55 and 74, enrolled in the PLCO Trial, with no history of prostate cancer. The men were initially screened through a PSA test and digital rectal exam, and were then followed through routine exams and screenings until first occurrence of prostate cancer, death or the end of the trial in 2001. At the beginning of the trial, the men gave a blood sample and completed a questionnaire related to their health, diet and lifestyle.
The researchers focused on non-Hispanic Caucasian men, as the small number of cases among other ethnic groups was statistically insignificant. They found no significant difference between those who had prostate cancer and those who did not in relation to the concentration of lycopene in their bloodstream. "Our results do not offer support for the benefits of lycopene against prostate cancer," Peters said.
Most surprisingly, says Peters, was the relationship between increased risk of aggressive prostate cancer – defined as disease that has spread beyond the prostate – and beta-carotene, another antioxidant found in many vegetables and commonly used as a dietary supplement.
This unexpected observation "may be due to chance, however beta carotene is already known to increase risk of lung cancer and cardiovascular disease in smokers," Peters said.
"While it would be counter-productive to advise people against eating carrots and leafy vegetables, I would say to be cautious about taking beta carotene supplements, particularly at high doses, and consult a physician," Peters said.
Tomatoes might be nutritious and tasty, but don’t count on them to prevent prostate cancer. In the May issue of Cancer Epidemiology, Biomarkers & Prevention, researchers based at the National Cancer Institute and Fred Hutchinson Cancer Research Center report that lycopene, an antioxidant predominately found in tomatoes, does not effectively prevent prostate cancer. In fact, the researchers noted an association between beta-carotene, an antioxidant related to lycopene, and an increased risk for aggressive prostate cancer.
According to the researchers, the study is one of the largest to evaluate the role of blood concentrations of lycopene and other carotenoid antioxidants in preventing prostate cancer. Study data were derived from over 28,000 men enrolled in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, an ongoing, randomized National Cancer Institute trial to evaluate cancer screening methods and to investigate early markers of cancer.
"It is disappointing, since lycopene might have offered a simple and inexpensive way to lower prostate cancer risk for men concerned about this common disease," said Ulrike Peters, Ph.D., M.P.H., of the Fred Hutchinson Cancer Research Center. "Unfortunately, this easy answer just does not work."
Previous studies suggested that a diet rich in lycopene protected against prostate cancer, spurring commercial and public interest in the antioxidant. Antioxidants protect against free radicals, highly reactive atoms and molecules that can damage DNA and other important molecules in the cell. Since free radical damage increases with age, there has been a long-held suspicion in the scientific community that free radical damage could increase the risk of prostate cancer, a disease that has been clearly associated with age.
Subsequent studies of the potentially protective role of lycopene have been contradictory or inconclusive, according to Peters. In a 2006 study, she and her colleagues looked at the dietary intake of more than 25 tomato-based foods, also using data from the PLCO trial, and found no overall association between lycopene intake and prostate cancer.
In their current study, the researchers followed over 28,000 men between the ages of 55 and 74, enrolled in the PLCO Trial, with no history of prostate cancer. The men were initially screened through a PSA test and digital rectal exam, and were then followed through routine exams and screenings until first occurrence of prostate cancer, death or the end of the trial in 2001. At the beginning of the trial, the men gave a blood sample and completed a questionnaire related to their health, diet and lifestyle.
The researchers focused on non-Hispanic Caucasian men, as the small number of cases among other ethnic groups was statistically insignificant. They found no significant difference between those who had prostate cancer and those who did not in relation to the concentration of lycopene in their bloodstream. "Our results do not offer support for the benefits of lycopene against prostate cancer," Peters said.
Most surprisingly, says Peters, was the relationship between increased risk of aggressive prostate cancer – defined as disease that has spread beyond the prostate – and beta-carotene, another antioxidant found in many vegetables and commonly used as a dietary supplement.
This unexpected observation "may be due to chance, however beta carotene is already known to increase risk of lung cancer and cardiovascular disease in smokers," Peters said.
"While it would be counter-productive to advise people against eating carrots and leafy vegetables, I would say to be cautious about taking beta carotene supplements, particularly at high doses, and consult a physician," Peters said.
Lipoic acid explored as anti-aging compound
Researchers said today they have identified the mechanism of action of lipoic acid, a remarkable compound that in animal experiments appears to slow down the process of aging, improve blood flow, enhance immune function and perform many other functions.
The findings, discussed at the "Diet and Optimum Health" conference sponsored by the Linus Pauling Institute at Oregon State University, shed light on how this micronutrient might perform such a wide range of beneficial functions.
"The evidence suggests that lipoic acid is actually a low-level stressor that turns on the basic cellular defenses of the body, including some of those that naturally decline with age," said Tory Hagen, an LPI researcher and associate professor of biochemistry and biophysics at OSU. "In particular, it tends to restore levels of glutathione, a protective antioxidant and detoxification compound, to those of a young animal. It also acts as a strong anti-inflammatory agent, which is relevant to many degenerative diseases."
Researchers at LPI are studying vitamins, dietary approaches and micronutrients that may be implicated in the aging or degenerative disease process, and say that lipoic acid appears to be one of those with the most compelling promise. It's normally found at low levels in green leafy vegetables, but can also be taken as a supplement.
According to Hagen, research on the natural processes of aging, and steps that could slow it or improve health until near the end of life, are of growing importance.
"We're coming into the middle of an aging epidemic in the country," he said. "In a short time more than 70 million Americans will be over 65. This is partly because of the Baby Boom, but also people are living longer, being saved with antibiotics and other medical treatments. In any case, it will be an unprecedented number of elderly people in this nation."
The goal of LPI research, Hagen said, is to address issues of "healthspan," not just lifespan – meaning the ability to live a long life with comparatively good health and vigor, free of degenerative disease, until very near death. The best mechanisms to accomplish that, scientists say, have everything to do with diet, exercise, healthy lifestyle habits and micronutrient intake.
At the moment, Hagen said, that's not the way things appear to be headed – diabetes is skyrocketing, about 50 percent of people over 65 have high blood pressure, heart disease often leads to permanent disability, and almost half of the elderly people in America have malnutrition that is easily preventable.
No single intervention can address all of these issues, Hagen said, but one that scientists keep coming back to is lipoic acid.
"Our studies have shown that mice supplemented with lipoic acid have a cognitive ability, behavior, and genetic expression of almost 100 detoxification and antioxidant genes that are comparable to that of young animals," Hagen said. "They aren't just living longer, they are living better – and that's the goal we're after."
What the OSU researchers now believe is that the role of lipoic acid is not so much a direct one to benefit cells, but rather an indirect aid that "kick starts" declining function in cells and helps them recover the functions that came more easily and naturally in young animals.
In various effects, lipoic acid appears to help restore a cellular "signaling" process that tends to break down in older blood vessels. It reduces mitochondrial decay in cells, which is closely linked to the symptoms of aging. With age, glutathione levels naturally decline, making older animals more susceptible to both free radicals and other environmental toxins – but lipoic acid can restore glutathione function to near normal. And the expression and function of other genes seems to come back to life.
"We never really expected such a surprising range of benefits from one compound," Hagen said. "This is really unprecedented, and we're pretty excited about it."
Many other presentations have been made at this conference on the role of diet, lifestyle and micronutrients in health and degenerative disease, including cancer, heart disease, neurological diseases and aging.
The conference is organized every two years by OSU's Linus Pauling Institute, and attracts leading experts from around the world in these research fields.
The findings, discussed at the "Diet and Optimum Health" conference sponsored by the Linus Pauling Institute at Oregon State University, shed light on how this micronutrient might perform such a wide range of beneficial functions.
"The evidence suggests that lipoic acid is actually a low-level stressor that turns on the basic cellular defenses of the body, including some of those that naturally decline with age," said Tory Hagen, an LPI researcher and associate professor of biochemistry and biophysics at OSU. "In particular, it tends to restore levels of glutathione, a protective antioxidant and detoxification compound, to those of a young animal. It also acts as a strong anti-inflammatory agent, which is relevant to many degenerative diseases."
Researchers at LPI are studying vitamins, dietary approaches and micronutrients that may be implicated in the aging or degenerative disease process, and say that lipoic acid appears to be one of those with the most compelling promise. It's normally found at low levels in green leafy vegetables, but can also be taken as a supplement.
According to Hagen, research on the natural processes of aging, and steps that could slow it or improve health until near the end of life, are of growing importance.
"We're coming into the middle of an aging epidemic in the country," he said. "In a short time more than 70 million Americans will be over 65. This is partly because of the Baby Boom, but also people are living longer, being saved with antibiotics and other medical treatments. In any case, it will be an unprecedented number of elderly people in this nation."
The goal of LPI research, Hagen said, is to address issues of "healthspan," not just lifespan – meaning the ability to live a long life with comparatively good health and vigor, free of degenerative disease, until very near death. The best mechanisms to accomplish that, scientists say, have everything to do with diet, exercise, healthy lifestyle habits and micronutrient intake.
At the moment, Hagen said, that's not the way things appear to be headed – diabetes is skyrocketing, about 50 percent of people over 65 have high blood pressure, heart disease often leads to permanent disability, and almost half of the elderly people in America have malnutrition that is easily preventable.
No single intervention can address all of these issues, Hagen said, but one that scientists keep coming back to is lipoic acid.
"Our studies have shown that mice supplemented with lipoic acid have a cognitive ability, behavior, and genetic expression of almost 100 detoxification and antioxidant genes that are comparable to that of young animals," Hagen said. "They aren't just living longer, they are living better – and that's the goal we're after."
What the OSU researchers now believe is that the role of lipoic acid is not so much a direct one to benefit cells, but rather an indirect aid that "kick starts" declining function in cells and helps them recover the functions that came more easily and naturally in young animals.
In various effects, lipoic acid appears to help restore a cellular "signaling" process that tends to break down in older blood vessels. It reduces mitochondrial decay in cells, which is closely linked to the symptoms of aging. With age, glutathione levels naturally decline, making older animals more susceptible to both free radicals and other environmental toxins – but lipoic acid can restore glutathione function to near normal. And the expression and function of other genes seems to come back to life.
"We never really expected such a surprising range of benefits from one compound," Hagen said. "This is really unprecedented, and we're pretty excited about it."
Many other presentations have been made at this conference on the role of diet, lifestyle and micronutrients in health and degenerative disease, including cancer, heart disease, neurological diseases and aging.
The conference is organized every two years by OSU's Linus Pauling Institute, and attracts leading experts from around the world in these research fields.
'Five-Second Rule' for Dropped Food More Like 30
Two Connecticut College student researchers have found that the "five-second rule" - which stipulates that dropped food will be safe to eat if it stays on the floor for fewer than five seconds - might better be known as the "30-second rule."
Connecticut College seniors and cell and molecular biology majors Molly Goettsche and Nicole Moin took two food samples - apple slices and Skittles candies - to the Connecticut College dining hall and snack bar. They dropped the foods onto the floors in both locations for five, 10, 30 and 60 second intervals, and also tested them after allowing five minutes to elapse. They then looked for any rogue bacteria that might have attached to the foods.
The researchers found no bacteria were present on the foods that had remained on the floor for five, 10 or 30 seconds. The apple slices did pick up bacteria after one minute, however, and the Skittles showed a bacterial presence after remaining on the floor for five minutes.
The results prove, according Goettsche and Moin, that you can wait at least 30 seconds to pick up wet foods and more than a minute to pick up dry foods before they become contaminated with bacteria.
"The five-second rule should probably be renamed," Goettsche said. "You actually have a little more time."
The research was conducted under the supervision of Anne Bernhard, assistant professor of biology at Connecticut College. Previous research on the rule, Moin said, was conducted by a University of Illinois researcher in 2003 and involved dropping food items directly onto e-coli contaminated tiles.
"That is not what is representative of what actually happens," Goettsche said. "We wanted to apply this to everyday life."
Connecticut College seniors and cell and molecular biology majors Molly Goettsche and Nicole Moin took two food samples - apple slices and Skittles candies - to the Connecticut College dining hall and snack bar. They dropped the foods onto the floors in both locations for five, 10, 30 and 60 second intervals, and also tested them after allowing five minutes to elapse. They then looked for any rogue bacteria that might have attached to the foods.
The researchers found no bacteria were present on the foods that had remained on the floor for five, 10 or 30 seconds. The apple slices did pick up bacteria after one minute, however, and the Skittles showed a bacterial presence after remaining on the floor for five minutes.
The results prove, according Goettsche and Moin, that you can wait at least 30 seconds to pick up wet foods and more than a minute to pick up dry foods before they become contaminated with bacteria.
"The five-second rule should probably be renamed," Goettsche said. "You actually have a little more time."
The research was conducted under the supervision of Anne Bernhard, assistant professor of biology at Connecticut College. Previous research on the rule, Moin said, was conducted by a University of Illinois researcher in 2003 and involved dropping food items directly onto e-coli contaminated tiles.
"That is not what is representative of what actually happens," Goettsche said. "We wanted to apply this to everyday life."
Wednesday, May 16, 2007
Heavy multivitamin use = advanced prostate cancer?
While regular multivitamin use is not linked with early or localized prostate cancer, taking too many multivitamins may be associated with an increased risk for advanced or fatal prostate cancers, according to a study in the May 16 issue of the Journal of the National Cancer Institute.
Millions of Americans take multivitamins because of a belief in their potential health benefits, even though there is limited scientific evidence that they prevent chronic disease. Researchers have wondered what impact multivitamin use might have on cancer risk.
Karla Lawson, Ph.D., of the National Cancer Institute in Bethesda, Md., and colleagues followed 295,344 men enrolled in the National Institutes of Health-AARP Diet and Health Study to determine the association between multivitamin use and prostate cancer risk. After five years of follow-up, 10,241 men were diagnosed with prostate cancer, including 8,765 with localized cancers and 1,476 with advanced cancers.
The researchers found no association between multivitamin use and the risk of localized prostate cancer. But they did find an increased risk of advanced and fatal prostate cancer among men who used multivitamins more than seven times a week, compared with men who did not use multivitamins. The association was strongest in men with a family history of prostate cancer and men who also took selenium, beta-carotene, or zinc supplements.
“Because multivitamin supplements consist of a combination of several vitamins and men using high levels of multivitamins were also more likely to take a variety of individual supplements, we were unable to identify or quantify individual components responsible for the associations that we observed,” the authors write.
Millions of Americans take multivitamins because of a belief in their potential health benefits, even though there is limited scientific evidence that they prevent chronic disease. Researchers have wondered what impact multivitamin use might have on cancer risk.
Karla Lawson, Ph.D., of the National Cancer Institute in Bethesda, Md., and colleagues followed 295,344 men enrolled in the National Institutes of Health-AARP Diet and Health Study to determine the association between multivitamin use and prostate cancer risk. After five years of follow-up, 10,241 men were diagnosed with prostate cancer, including 8,765 with localized cancers and 1,476 with advanced cancers.
The researchers found no association between multivitamin use and the risk of localized prostate cancer. But they did find an increased risk of advanced and fatal prostate cancer among men who used multivitamins more than seven times a week, compared with men who did not use multivitamins. The association was strongest in men with a family history of prostate cancer and men who also took selenium, beta-carotene, or zinc supplements.
“Because multivitamin supplements consist of a combination of several vitamins and men using high levels of multivitamins were also more likely to take a variety of individual supplements, we were unable to identify or quantify individual components responsible for the associations that we observed,” the authors write.
Subscribe to:
Posts (Atom)