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Scientists at the Helmholtz Zentrum München have shown that people with a good vitamin D supply are at lower risk of developing Type 2 diabetes mellitus. The study, which was conducted in cooperation with the German Diabetes Center and the University of Ulm, will be published in the October edition of the scientific journal Diabetes Care.
New tests performed on participants of the KORA study have shown that people with a good supply of vitamin D have a lower risk of developing Type 2 diabetes mellitus, while individuals with lower concentrations of vitamin D in their blood have a higher risk. This effect could be attributable, amongst other things, to the anti-inflammatory effect of vitamin D. The result of the study, which was conducted at the Helmholtz Zentrum München in cooperation with Dr. Christian Herder of the German Diabetes Center in Düsseldorf and Dr. Wolfgang König, Professor of Medicine/Cardiology at the University of Ulm, could have direct consequences for the prevention of this common disease.
"Vitamin D deficiency is relatively widespread due to our modern way of life and the geographical latitude of Germany. In the winter months, in particular, people often do not receive adequate supplies of the vitamin because of the lack of sunlight," explains Dr. Barbara Thorand of the Institute for Epidemiology II at the Helmholtz Zentrum München. "If follow-up studies confirm our results, a targeted improvement in the supply of vitamin D to the general public could at the same time reduce the risk of developing diabetes." The human body can produce vitamin D itself if it has sufficient exposure to sunlight. The UVB radiation in natural daylight splits the precursor of vitamin D, 7-dehydrocholesterol, in the skin and forms provitamin D3. Further vitamin D synthesis occurs in the liver and kidneys. In addition, the supply can be improved by eating specific foods, such as oily fish, eggs and milk products, or by taking vitamin D supplements.
Wednesday, October 5, 2011
Tuesday, October 4, 2011
Reducing iron may lower age-related brain disease risk
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"But there are things postmenopausal women and especially men can do to reduce their iron levels through relatively simple actions," Bartzokis said. "These include not overloading themselves with over-the-counter supplements that contain iron, unless recommended by their doctor; eating less red meat, which contains high levels of iron; donating blood; and possibly taking natural iron-chelating substances, molecules that bind to and remove iron, such as curcumin or green tea, that may have positive health consequences."
The human body has a love-hate relationship with iron. Just the right amount is needed for proper cell function, yet too much is associated with brain diseases like Alzheimer's and Parkinson's.
Science knows that men have more iron in their bodies and brains than women. These higher levels may be part of the explanation for why men develop these age-related neurodegenerative diseases at a younger age.
But why do women have less iron in their systems than men? One possible explanation for the gender difference is that during menstruation, iron is eliminated through the loss of blood.
Now, a new study by UCLA researchers confirms this suspicion and suggests strategies to reduce excess iron levels in both men and women. Dr. George Bartzokis, a professor of psychiatry at the Semel Institute for Neuroscience and Human Behavior at UCLA, and colleagues compared iron levels in women who had undergone a hysterectomy before menopause -- and thus, did not menstruate and lose iron -- with levels in postmenopausal women who had not had a premenopausal hysterectomy. They found the women who had undergone a hysterectomy had higher levels of iron in their brains than the women who hadn't, and further, they had levels that were comparable to men.
The research is reported in the current online edition of the journal Neurobiology of Aging.
The researchers used an MRI technique that can measure the amount of ferritin iron in the brain (ferritin is a protein that stores iron). They examined 39 postmenopausal women, 15 of whom had undergone a premenopausal hysterectomy. They looked at several areas in the brain three white-matter regions and and five gray-matter regions. Fifty-four male subjects were also imaged for comparison.
The researchers found that among the women, the 15 who had undergone a hysterectomy had concentrations of iron in the white-matter regions of the brain's frontal lobe that did not differ from the men's levels. Further, both the women who had a hysterectomy and the men had significantly higher amounts of iron than the women who had not undergone a hysterectomy. (Gray matter areas showed slight increases that were not statistically significant.)
Hysterectomy is the most common non-obstetrical surgery among women in the United States, with one in three having had a hysterectomy by age 60, said Bartzokis, who is also a member of the UCLA Laboratory of Neuro Imaging and the UCLA Brain Research Institute.
The results of this study, he said, suggest that menstruation-associated blood loss may explain gender differences in brain iron. And of interest to both men and women, he said, is that it's possible that brain iron can be influenced by peripheral iron levels -- that is, iron levels throughout the body -- and may thus be a modifiable risk factor for age-related degenerative diseases.
"Iron accumulates in our bodies as we age," Bartzokis said, "and in the brain contributes to the development of abnormal deposits of proteins associated with several prevalent neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease and dementia with Lewy bodies. Higher brain iron levels in men may be part of the explanation for why men develop these age-related neurodegenerative diseases at a younger age, compared to women."
Bartzokis suggests it may be possible to reduce age-related brain iron accumulations by reducing the levels of iron throughout the body. This may have health benefits, especially in men, and may help counteract the negative effects of aging on the brain by reducing the iron available to catalyze, or speed up, damaging free-radical reactions.
There are a few ways body stores of iron can be reduced naturally, especially for premenopausal women. Menstruation leads to the elimination of iron through loss of blood. During pregnancy, iron is transferred from the woman to the fetus, and when women breast-feed, iron is transferred to the baby through the mother's milk.
"But there are things postmenopausal women and especially men can do to reduce their iron levels through relatively simple actions," Bartzokis said. "These include not overloading themselves with over-the-counter supplements that contain iron, unless recommended by their doctor; eating less red meat, which contains high levels of iron; donating blood; and possibly taking natural iron-chelating substances, molecules that bind to and remove iron, such as curcumin or green tea, that may have positive health consequences."
The human body has a love-hate relationship with iron. Just the right amount is needed for proper cell function, yet too much is associated with brain diseases like Alzheimer's and Parkinson's.
Science knows that men have more iron in their bodies and brains than women. These higher levels may be part of the explanation for why men develop these age-related neurodegenerative diseases at a younger age.
But why do women have less iron in their systems than men? One possible explanation for the gender difference is that during menstruation, iron is eliminated through the loss of blood.
Now, a new study by UCLA researchers confirms this suspicion and suggests strategies to reduce excess iron levels in both men and women. Dr. George Bartzokis, a professor of psychiatry at the Semel Institute for Neuroscience and Human Behavior at UCLA, and colleagues compared iron levels in women who had undergone a hysterectomy before menopause -- and thus, did not menstruate and lose iron -- with levels in postmenopausal women who had not had a premenopausal hysterectomy. They found the women who had undergone a hysterectomy had higher levels of iron in their brains than the women who hadn't, and further, they had levels that were comparable to men.
The research is reported in the current online edition of the journal Neurobiology of Aging.
The researchers used an MRI technique that can measure the amount of ferritin iron in the brain (ferritin is a protein that stores iron). They examined 39 postmenopausal women, 15 of whom had undergone a premenopausal hysterectomy. They looked at several areas in the brain three white-matter regions and and five gray-matter regions. Fifty-four male subjects were also imaged for comparison.
The researchers found that among the women, the 15 who had undergone a hysterectomy had concentrations of iron in the white-matter regions of the brain's frontal lobe that did not differ from the men's levels. Further, both the women who had a hysterectomy and the men had significantly higher amounts of iron than the women who had not undergone a hysterectomy. (Gray matter areas showed slight increases that were not statistically significant.)
Hysterectomy is the most common non-obstetrical surgery among women in the United States, with one in three having had a hysterectomy by age 60, said Bartzokis, who is also a member of the UCLA Laboratory of Neuro Imaging and the UCLA Brain Research Institute.
The results of this study, he said, suggest that menstruation-associated blood loss may explain gender differences in brain iron. And of interest to both men and women, he said, is that it's possible that brain iron can be influenced by peripheral iron levels -- that is, iron levels throughout the body -- and may thus be a modifiable risk factor for age-related degenerative diseases.
"Iron accumulates in our bodies as we age," Bartzokis said, "and in the brain contributes to the development of abnormal deposits of proteins associated with several prevalent neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease and dementia with Lewy bodies. Higher brain iron levels in men may be part of the explanation for why men develop these age-related neurodegenerative diseases at a younger age, compared to women."
Bartzokis suggests it may be possible to reduce age-related brain iron accumulations by reducing the levels of iron throughout the body. This may have health benefits, especially in men, and may help counteract the negative effects of aging on the brain by reducing the iron available to catalyze, or speed up, damaging free-radical reactions.
There are a few ways body stores of iron can be reduced naturally, especially for premenopausal women. Menstruation leads to the elimination of iron through loss of blood. During pregnancy, iron is transferred from the woman to the fetus, and when women breast-feed, iron is transferred to the baby through the mother's milk.
Could soccer give homeless men a health kick?
Ω
Playing street football two or three times a week could halve the risk of early death in homeless men. Research led by the Universities of Exeter and Copenhagen, out today (3 October), shows the positive impact of street football on the fitness of homeless people, a group with typically poor health and low life expectancy.
Homeless people face a much lower-than-average life expectancy, usually as a result of cardiovascular disease. This is thought to be partly down to low aerobic fitness and high levels of hypertension and the fact that homeless people are, on average, more likely to smoke and misuse alcohol and other drugs. While homeless people tend to undertake large amounts of low-intensity physical exercise, through more than 10,000 daily steps of walking, most do not take part in more intensive exercise.
To address this problem, charities and government agencies have tried schemes such as offering gym memberships to homeless people.
For this study, 55 homeless men living in Copenhagen were included in a control group or invited to attend four-a-side football training sessions two to three times a week for 12 weeks. By the end, the aerobic fitness of the football-playing group was improved and their cholesterol, body fat and blood pressure reduced.
The footballers' average maximal oxygen uptake was increased 11 percent (four ml/min/kg bodyweight). Previous scientific studies have suggested that the risk of death decreases by around 50% through this increase in maximal oxygen uptake. Body fat was reduced by an average of 2.5 per cent and LDL-cholesterol by 6.4 per cent.
Lead author Professor Peter Krustrup of the University of Exeter said: "Street football for homeless men is very intense and 12 weeks of training significantly improves the fitness and cardiovascular health profile of these men. We also observed a very high attendance rate, which is promising for future adherence to physical activity."
"Football seems to be a great type of fitness training for most people. Not only does it encourage varied, intense training, it is social and it can be played anywhere."
Collaborating researcher, Professor Merete Nordentoft of the Psychiatric Center Copenhagen, University of Copenhagen, concludes: "There seems to be great potential for improving the quality of many people's lives if local agencies could organise street football groups for homeless people."
Playing street football two or three times a week could halve the risk of early death in homeless men. Research led by the Universities of Exeter and Copenhagen, out today (3 October), shows the positive impact of street football on the fitness of homeless people, a group with typically poor health and low life expectancy.
Homeless people face a much lower-than-average life expectancy, usually as a result of cardiovascular disease. This is thought to be partly down to low aerobic fitness and high levels of hypertension and the fact that homeless people are, on average, more likely to smoke and misuse alcohol and other drugs. While homeless people tend to undertake large amounts of low-intensity physical exercise, through more than 10,000 daily steps of walking, most do not take part in more intensive exercise.
To address this problem, charities and government agencies have tried schemes such as offering gym memberships to homeless people.
For this study, 55 homeless men living in Copenhagen were included in a control group or invited to attend four-a-side football training sessions two to three times a week for 12 weeks. By the end, the aerobic fitness of the football-playing group was improved and their cholesterol, body fat and blood pressure reduced.
The footballers' average maximal oxygen uptake was increased 11 percent (four ml/min/kg bodyweight). Previous scientific studies have suggested that the risk of death decreases by around 50% through this increase in maximal oxygen uptake. Body fat was reduced by an average of 2.5 per cent and LDL-cholesterol by 6.4 per cent.
Lead author Professor Peter Krustrup of the University of Exeter said: "Street football for homeless men is very intense and 12 weeks of training significantly improves the fitness and cardiovascular health profile of these men. We also observed a very high attendance rate, which is promising for future adherence to physical activity."
"Football seems to be a great type of fitness training for most people. Not only does it encourage varied, intense training, it is social and it can be played anywhere."
Collaborating researcher, Professor Merete Nordentoft of the Psychiatric Center Copenhagen, University of Copenhagen, concludes: "There seems to be great potential for improving the quality of many people's lives if local agencies could organise street football groups for homeless people."
Pale people may need vitamin D supplements
Ω
Researchers at the University of Leeds, funded by Cancer Research UK, suggest that people with very pale skin may be unable to spend enough time in the sun to make the amount of vitamin D the body needs - while also avoiding sunburn.
The study, published in Cancer Causes and Control*, suggested that melanoma patients may need vitamin D supplements as well.
But researchers also noted that sunlight and supplements are not the only factors that can determine the level of vitamin D in a person's body.
Some inherited differences in the way people's bodies process vitamin D into the active form also have a strong effect on people's vitamin D levels.
The study defined the optimal amount of vitamin D required by the body as at least 60nmol/L. However at present there is no universally agreed standard definition of an optimal level of vitamin D.
Professor Julia Newton-Bishop, lead author of the study based in the Cancer Research UK Centre at the University of Leeds, said: "Fair-skinned individuals who burn easily are not able to make enough vitamin D from sunlight and so may need to take vitamin D supplements.
"This should be considered for fair-skinned people living in a mild climate like the UK and melanoma patients in particular."
Researchers took the vitamin D levels of around 1,200 people and found that around 730 people had a sub-optimal level. Those with fair-skin had significantly lower levels. Researchers chose 60nmol/L as the optimal vitamin D level in part because there is evidence that levels lower than this may be linked to greater risk of heart disease and poorer survival from breast cancer.
A consensus between health charities including Cancer Research UK says that levels below 25nmol/L are vitamin D deficient which means that these levels are associated with poor bone health. But some researchers consider that higher levels, around 60nmol/l, may be desirable for optimal health effects.
Sara Hiom, director of health information at Cancer Research UK, said: "We must be careful about raising the definition of deficiency or sufficiency to higher levels until we have more results from trials showing that maintaining such levels has clear health benefits and no health risks.
"If you are worried about your vitamin D levels, our advice is to go see your doctor."
Researchers at the University of Leeds, funded by Cancer Research UK, suggest that people with very pale skin may be unable to spend enough time in the sun to make the amount of vitamin D the body needs - while also avoiding sunburn.
The study, published in Cancer Causes and Control*, suggested that melanoma patients may need vitamin D supplements as well.
But researchers also noted that sunlight and supplements are not the only factors that can determine the level of vitamin D in a person's body.
Some inherited differences in the way people's bodies process vitamin D into the active form also have a strong effect on people's vitamin D levels.
The study defined the optimal amount of vitamin D required by the body as at least 60nmol/L. However at present there is no universally agreed standard definition of an optimal level of vitamin D.
Professor Julia Newton-Bishop, lead author of the study based in the Cancer Research UK Centre at the University of Leeds, said: "Fair-skinned individuals who burn easily are not able to make enough vitamin D from sunlight and so may need to take vitamin D supplements.
"This should be considered for fair-skinned people living in a mild climate like the UK and melanoma patients in particular."
Researchers took the vitamin D levels of around 1,200 people and found that around 730 people had a sub-optimal level. Those with fair-skin had significantly lower levels. Researchers chose 60nmol/L as the optimal vitamin D level in part because there is evidence that levels lower than this may be linked to greater risk of heart disease and poorer survival from breast cancer.
A consensus between health charities including Cancer Research UK says that levels below 25nmol/L are vitamin D deficient which means that these levels are associated with poor bone health. But some researchers consider that higher levels, around 60nmol/l, may be desirable for optimal health effects.
Sara Hiom, director of health information at Cancer Research UK, said: "We must be careful about raising the definition of deficiency or sufficiency to higher levels until we have more results from trials showing that maintaining such levels has clear health benefits and no health risks.
"If you are worried about your vitamin D levels, our advice is to go see your doctor."
Vitamin D deficiency common in cancer patients
Ω
More than three-quarters of cancer patients have insufficient levels of vitamin D (25-hydroxy-vitamin D) and the lowest levels are associated with more advanced cancer, according to a study presented on October 2, 2011, at the 53rd Annual Meeting of the American Society for Radiation Oncology (ASTRO).
"Until recently, studies have not investigated whether vitamin D has an impact on the prognosis or course of cancer. Researchers are just starting to examine how vitamin D may impact specific features of cancer, such as the stage or extent of tumor spread, prognosis, recurrence or relapse of disease, and even sub-types of cancer," Thomas Churilla, lead author of the study and a medical student at the Commonwealth Medical College, Scranton, Pa., said.
Researchers sought to determine the vitamin D levels of patients at Northeast Radiation Oncology Center in Dunmore, Pa., a community oncology practice, and to see if vitamin D levels were related to any specific aspects of cancer. The study involved 160 patients with a median age of 64 years and a 1:1 ratio of men to women. The five most common primary diagnoses were breast, prostate, lung, thyroid and colorectal cancer. A total of 77 percent of patients had vitamin D concentrations either deficient (less than 20 ng/mL) or sub-optimal (20-30 ng/mL). The median serum vitamin D level was 23.5 ng/mL. Regardless of the age or sex of the patient, levels of vitamin D were below the median predicted for advanced stage disease in the patient group.
Patients who were found to be vitamin D deficient were administered replacement therapy, increasing serum D levels by an average of 14.9 ng/mL. Investigators will be analyzing if vitamin D supplementation had an impact on aspects of treatment or survival in the long-term.
"The benefits of vitamin D outside of improving bone health are controversial, yet there are various levels of evidence to support that vitamin D has a role in either the prevention or the prediction of outcome of cancer," Churilla said. "Further study is needed to continue to understand the relationship between vitamin D and cancer."
More than three-quarters of cancer patients have insufficient levels of vitamin D (25-hydroxy-vitamin D) and the lowest levels are associated with more advanced cancer, according to a study presented on October 2, 2011, at the 53rd Annual Meeting of the American Society for Radiation Oncology (ASTRO).
"Until recently, studies have not investigated whether vitamin D has an impact on the prognosis or course of cancer. Researchers are just starting to examine how vitamin D may impact specific features of cancer, such as the stage or extent of tumor spread, prognosis, recurrence or relapse of disease, and even sub-types of cancer," Thomas Churilla, lead author of the study and a medical student at the Commonwealth Medical College, Scranton, Pa., said.
Researchers sought to determine the vitamin D levels of patients at Northeast Radiation Oncology Center in Dunmore, Pa., a community oncology practice, and to see if vitamin D levels were related to any specific aspects of cancer. The study involved 160 patients with a median age of 64 years and a 1:1 ratio of men to women. The five most common primary diagnoses were breast, prostate, lung, thyroid and colorectal cancer. A total of 77 percent of patients had vitamin D concentrations either deficient (less than 20 ng/mL) or sub-optimal (20-30 ng/mL). The median serum vitamin D level was 23.5 ng/mL. Regardless of the age or sex of the patient, levels of vitamin D were below the median predicted for advanced stage disease in the patient group.
Patients who were found to be vitamin D deficient were administered replacement therapy, increasing serum D levels by an average of 14.9 ng/mL. Investigators will be analyzing if vitamin D supplementation had an impact on aspects of treatment or survival in the long-term.
"The benefits of vitamin D outside of improving bone health are controversial, yet there are various levels of evidence to support that vitamin D has a role in either the prevention or the prediction of outcome of cancer," Churilla said. "Further study is needed to continue to understand the relationship between vitamin D and cancer."
Green tea may slow down weight gain
Ω
Green tea may slow down weight gain and serve as another tool in the fight against obesity, according to Penn State food scientists.
Obese mice that were fed a compound found in green tea along with a high-fat diet gained weight significantly more slowly than a control group of mice that did not receive the green tea supplement, said Joshua Lambert, assistant professor of food science in agricultural sciences.
"In this experiment, we see the rate of body weight gain slows down," said Lambert.
The researchers, who released their findings in the current online version of Obesity, fed two groups of mice a high-fat diet. Mice that were fed Epigallocatechin-3-gallate -- EGCG -- a compound found in most green teas, along with a high-fat diet, gained weight 45 percent more slowly than the control group of mice eating the same diet without EGCG.
"Our results suggest that if you supplement with EGCG or green tea you gain weight more slowly," said Lambert.
In addition to lower weight gain, the mice fed the green tea supplement showed a nearly 30 percent increase in fecal lipids, suggesting that the EGCG was limiting fat absorption, according to Lambert.
"There seems to be two prongs to this," said Lambert. "First, EGCG reduces the ability to absorb fat and, second, it enhances the ability to use fat."
The green tea did not appear to suppress appetite. Both groups of mice were fed the same amount of high-fat food and could eat at any time.
"There's no difference in the amount of food the mice are eating," said Lambert. "The mice are essentially eating a milkshake, except one group is eating a milkshake with green tea."
A person would need to drink ten cups of green tea each day to match the amount of EGCG used in the study, according to Lambert. However, he said recent studies indicate that just drinking a few cups of green tea may help control weight.
"Human data -- and there's not a lot at this point -- shows that tea drinkers who only consume one or more cups a day will see effects on body weight compared to nonconsumers," said Lambert.
Lambert, who worked with Kimberly Grove and Sudathip Sae-tan, both graduate students in food science, and Mary Kennett, professor of veterinary and biomedical sciences, said that other experiments have shown that lean mice did not gain as much weight when green tea is added to a high fat diet. However, he said that studying mice that are already overweight is more relevant to humans because people often consider dietary changes only when they notice problems associated with obesity.
"Most people hit middle age and notice a paunch; then you decide to eat less, exercise and add green tea supplement," said Lambert.
Green tea may slow down weight gain and serve as another tool in the fight against obesity, according to Penn State food scientists.
Obese mice that were fed a compound found in green tea along with a high-fat diet gained weight significantly more slowly than a control group of mice that did not receive the green tea supplement, said Joshua Lambert, assistant professor of food science in agricultural sciences.
"In this experiment, we see the rate of body weight gain slows down," said Lambert.
The researchers, who released their findings in the current online version of Obesity, fed two groups of mice a high-fat diet. Mice that were fed Epigallocatechin-3-gallate -- EGCG -- a compound found in most green teas, along with a high-fat diet, gained weight 45 percent more slowly than the control group of mice eating the same diet without EGCG.
"Our results suggest that if you supplement with EGCG or green tea you gain weight more slowly," said Lambert.
In addition to lower weight gain, the mice fed the green tea supplement showed a nearly 30 percent increase in fecal lipids, suggesting that the EGCG was limiting fat absorption, according to Lambert.
"There seems to be two prongs to this," said Lambert. "First, EGCG reduces the ability to absorb fat and, second, it enhances the ability to use fat."
The green tea did not appear to suppress appetite. Both groups of mice were fed the same amount of high-fat food and could eat at any time.
"There's no difference in the amount of food the mice are eating," said Lambert. "The mice are essentially eating a milkshake, except one group is eating a milkshake with green tea."
A person would need to drink ten cups of green tea each day to match the amount of EGCG used in the study, according to Lambert. However, he said recent studies indicate that just drinking a few cups of green tea may help control weight.
"Human data -- and there's not a lot at this point -- shows that tea drinkers who only consume one or more cups a day will see effects on body weight compared to nonconsumers," said Lambert.
Lambert, who worked with Kimberly Grove and Sudathip Sae-tan, both graduate students in food science, and Mary Kennett, professor of veterinary and biomedical sciences, said that other experiments have shown that lean mice did not gain as much weight when green tea is added to a high fat diet. However, he said that studying mice that are already overweight is more relevant to humans because people often consider dietary changes only when they notice problems associated with obesity.
"Most people hit middle age and notice a paunch; then you decide to eat less, exercise and add green tea supplement," said Lambert.
Monday, October 3, 2011
Small Amount of Exercise Could Protect Against Memory Loss
Ω
A new University of Colorado Boulder study shows that a small amount of physical exercise could profoundly protect the elderly from long-term memory loss that can happen suddenly following infection, illnesses or injury in old age.
In the study, CU-Boulder Research Associate Ruth Barrientos and her colleagues showed that aging rats that ran just over half a kilometer each week were protected against infection-induced memory loss.
"Our research shows that a small amount of physical exercise by late middle-aged rats profoundly protects against exaggerated inflammation in the brain and long-lasting memory impairments that follow a serious bacterial infection," said Barrientos of the psychology and neuroscience department.
The results of the study will appear in the Aug. 10 edition of The Journal of Neuroscience.
"Strikingly, this small amount of running was sufficient to confer robust benefits for those that ran over those that did not run," Barrientos said. "This is an important finding because those of advanced age are more vulnerable to memory impairments following immune challenges such as bacterial infections or surgery. With baby boomers currently at retirement age, the risk of diminished memory function in this population is of great concern. Thus, effective noninvasive therapies are of substantial clinical value."
Past research has shown that exercise in humans protects against declines in cognitive function associated with aging and protects against dementia. Researchers also have shown that dementia is often preceded by bacterial infections, such as pneumonia, or other immune challenges.
"To the best of our knowledge, this is the first study to show that voluntary exercise in rats reduces aging-induced susceptibility to the cognitive impairments that follow a bacterial infection, and the processes thought to underlie these impairments," Barrientos said.
In the study, the researchers found that rats infected with E. coli bacteria experienced detrimental effects on the hippocampus, an area of the brain that mediates learning and memory.
Previous research has shown that immune cells of the brain, called microglia, become more reactive with age. When the older rats in the study encountered a bacterial infection, these immune cells released inflammatory molecules called cytokines in an exaggerated and prolonged manner.
"In the current study we found that small amounts of voluntary exercise prevented the priming of microglia, the exaggerated inflammation in the brain, and the decrease of growth factors," Barrientos said.
The next step of this research is to examine the role that stress hormones may play in sensitizing microglia, and whether physical exercise slows these hormones in older rats, she said.
A new University of Colorado Boulder study shows that a small amount of physical exercise could profoundly protect the elderly from long-term memory loss that can happen suddenly following infection, illnesses or injury in old age.
In the study, CU-Boulder Research Associate Ruth Barrientos and her colleagues showed that aging rats that ran just over half a kilometer each week were protected against infection-induced memory loss.
"Our research shows that a small amount of physical exercise by late middle-aged rats profoundly protects against exaggerated inflammation in the brain and long-lasting memory impairments that follow a serious bacterial infection," said Barrientos of the psychology and neuroscience department.
The results of the study will appear in the Aug. 10 edition of The Journal of Neuroscience.
"Strikingly, this small amount of running was sufficient to confer robust benefits for those that ran over those that did not run," Barrientos said. "This is an important finding because those of advanced age are more vulnerable to memory impairments following immune challenges such as bacterial infections or surgery. With baby boomers currently at retirement age, the risk of diminished memory function in this population is of great concern. Thus, effective noninvasive therapies are of substantial clinical value."
Past research has shown that exercise in humans protects against declines in cognitive function associated with aging and protects against dementia. Researchers also have shown that dementia is often preceded by bacterial infections, such as pneumonia, or other immune challenges.
"To the best of our knowledge, this is the first study to show that voluntary exercise in rats reduces aging-induced susceptibility to the cognitive impairments that follow a bacterial infection, and the processes thought to underlie these impairments," Barrientos said.
In the study, the researchers found that rats infected with E. coli bacteria experienced detrimental effects on the hippocampus, an area of the brain that mediates learning and memory.
Previous research has shown that immune cells of the brain, called microglia, become more reactive with age. When the older rats in the study encountered a bacterial infection, these immune cells released inflammatory molecules called cytokines in an exaggerated and prolonged manner.
"In the current study we found that small amounts of voluntary exercise prevented the priming of microglia, the exaggerated inflammation in the brain, and the decrease of growth factors," Barrientos said.
The next step of this research is to examine the role that stress hormones may play in sensitizing microglia, and whether physical exercise slows these hormones in older rats, she said.
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