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A new study finds high folate intake is associated with a reduced risk of colorectal cancer, a finding consistent with the findings of most previous epidemiologic studies. The study is reassuring, as previous recent evidence has suggested that consumption of very high levels of folate through supplements and from folate-fortified diet may increase risk of some cancers. Nonetheless, the potential importance of folate in colorectal cancer prevention remains in question because at least one other study found folate supplementation had no effect on recurrence of colorectal adenomas, precursors to colorectal cancer.
The study appears in Gastroenterology, and is the first to look at the association of folate with colorectal cancer risk with follow-up entirely after the mandatory fortification of the U.S. diet with folate. It also is the first to distinguish between the forms of folate found naturally in forms and folic acid, the form used for fortification and in supplements.
A research team led by Victoria Stevens, Ph.D., strategic director of laboratory services at the American Cancer Society, investigated the association between folate intake and colorectal cancer among 99,523 participants in the Cancer Prevention Study II Nutrition Cohort. A total of 1,023 participants were diagnosed with colorectal cancer between 1999 and 2007, a period entirely after folate fortification began. Neither higher nor lower risk was observed during the first two years of follow-up (1999 to 2001), but during 2002 to 2007, high folate intake was associated with a reduced risk of colorectal cancer.
"While folate fortification has been a public health success in reducing the risk of neural tube defects, the potential for an increase risk of cancer has been legitimate," said Dr. Stevens. "Our study population included many participants who consumed these very high levels of folate and we found no increased risk of colorectal cancer in these individuals. Nonetheless, one randomized clinical trial failed to show folate supplementation reduced the risk of adenomas, the non-cancerous colon polyps that can become cancerous, so we need to continue to investigate the influence of folate on cancer development in high risk populations as well as potential differences in the action of natural and synthetic form of this vitamin."
Wednesday, July 6, 2011
Vitamin D fights macular degeneration
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Diet can significantly influence course of macular degeneration among individuals with the same genetic susceptibility - a healthy diet with lots of fruits and vegetables, can also make a difference.
Eating a diet high in vitamin D, as well as the nutrients betaine and methionine, might help reduce the risk of macular degeneration, according to new research conducted by Tufts Medical Center scientists. Their study of identical twins from the US World War II Twin Registry also found that the more a person smoked, the higher their risk of developing macular degeneration. The study, “Smoking, Dietary Betaine, Methionine, and Vitamin D in Monozygotic Twins with Discordant Macular Degeneration: Epigenetic Implications” published in the journal Ophthalmology on July 1, is the first to look at identical twin pairs in which one twin had early age-related macular degeneration (AMD), and the other had late stage AMD.
AMD is highly heritable, with genetic factors determining up to 71 percent of the disease’s severity as determined by a previous study of this twin registry by this same research team. By examining identical twins with the same genes but whose disease was at different stages, researchers were able to identify environmental and behavioral factors that may contribute to severity of the disease. “We wanted to know why, if they have the same genes, do they have different stages of the disease?’’ said lead researcher Johanna M. Seddon, MD, ScM, Director of the Epidemiology and Genetics Service, Tufts Medical Center, and Professor of Ophthalmology, Tufts Universtity School of Medicine.
“Eat a healthy diet with lots of fruits and vegetables, and that can make a difference - even if you have a genetic susceptibility to macular degeneration,’’ said Seddon, a specialist in macular degeneration, and, of course, don’t smoke.’’
Macular degeneration is one of the leading causes of vision loss in older Americans. It occurs when cells in the macula, the part of the eye responsible for clear central vision, gradually die. Macular degeneration can progress so slowly it takes years for serious vision loss to occur but it can also develop rapidly, causing severe vision loss that can make it difficult to drive, read or conduct daily tasks.
Each twin completed a questionnaire about nutritional and health behaviors. The study found that twins whose macular degeneration was at the early stages tended to consume more vitamin D from dietary sources such as fish or milk than their brothers. Vitamin D may reduce the risk of macular degeneration because it has anti-inflammatory properties. It may also block the formation of new blood vessels that can grow under the macula, leaking blood and causing vision loss in the more severe stages of the disease. Similarly, Dr. Seddon’s research team also found that higher intakes of betaine and methionine were linked to a slower progression of the disease. These nutrients have also been linked to epigenetic mechanisms, which is a change in DNA, not attributable to a change in the actual DNA sequence. Betaine is found in fish, grains and spinach, while methionine is found in poultry, fish and dairy foods.
The study also found that among the pairs of twins, the twin who was the heavier smoker tended to have the more severe case of macular degeneration. These results indicate that both genetic susceptibility and environmental factors are important, that epigenetic factors may also be involved, and further underscores the importance of modifiable behaviors, especially avoiding smoking and eating a healthy diet, to help prevent or delay the progression of macular degeneration.
The study evaluated pairs of elderly male twins and used a survey of personal dietary and health habits to determine variations.
Diet can significantly influence course of macular degeneration among individuals with the same genetic susceptibility - a healthy diet with lots of fruits and vegetables, can also make a difference.
Eating a diet high in vitamin D, as well as the nutrients betaine and methionine, might help reduce the risk of macular degeneration, according to new research conducted by Tufts Medical Center scientists. Their study of identical twins from the US World War II Twin Registry also found that the more a person smoked, the higher their risk of developing macular degeneration. The study, “Smoking, Dietary Betaine, Methionine, and Vitamin D in Monozygotic Twins with Discordant Macular Degeneration: Epigenetic Implications” published in the journal Ophthalmology on July 1, is the first to look at identical twin pairs in which one twin had early age-related macular degeneration (AMD), and the other had late stage AMD.
AMD is highly heritable, with genetic factors determining up to 71 percent of the disease’s severity as determined by a previous study of this twin registry by this same research team. By examining identical twins with the same genes but whose disease was at different stages, researchers were able to identify environmental and behavioral factors that may contribute to severity of the disease. “We wanted to know why, if they have the same genes, do they have different stages of the disease?’’ said lead researcher Johanna M. Seddon, MD, ScM, Director of the Epidemiology and Genetics Service, Tufts Medical Center, and Professor of Ophthalmology, Tufts Universtity School of Medicine.
“Eat a healthy diet with lots of fruits and vegetables, and that can make a difference - even if you have a genetic susceptibility to macular degeneration,’’ said Seddon, a specialist in macular degeneration, and, of course, don’t smoke.’’
Macular degeneration is one of the leading causes of vision loss in older Americans. It occurs when cells in the macula, the part of the eye responsible for clear central vision, gradually die. Macular degeneration can progress so slowly it takes years for serious vision loss to occur but it can also develop rapidly, causing severe vision loss that can make it difficult to drive, read or conduct daily tasks.
Each twin completed a questionnaire about nutritional and health behaviors. The study found that twins whose macular degeneration was at the early stages tended to consume more vitamin D from dietary sources such as fish or milk than their brothers. Vitamin D may reduce the risk of macular degeneration because it has anti-inflammatory properties. It may also block the formation of new blood vessels that can grow under the macula, leaking blood and causing vision loss in the more severe stages of the disease. Similarly, Dr. Seddon’s research team also found that higher intakes of betaine and methionine were linked to a slower progression of the disease. These nutrients have also been linked to epigenetic mechanisms, which is a change in DNA, not attributable to a change in the actual DNA sequence. Betaine is found in fish, grains and spinach, while methionine is found in poultry, fish and dairy foods.
The study also found that among the pairs of twins, the twin who was the heavier smoker tended to have the more severe case of macular degeneration. These results indicate that both genetic susceptibility and environmental factors are important, that epigenetic factors may also be involved, and further underscores the importance of modifiable behaviors, especially avoiding smoking and eating a healthy diet, to help prevent or delay the progression of macular degeneration.
The study evaluated pairs of elderly male twins and used a survey of personal dietary and health habits to determine variations.
Eggs may help prevent heart disease and cancer
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One of nature's most perfect foods may be even better for us than previously thought.
While eggs are well known to be an excellent source of proteins, lipids, vitamins and minerals, researchers at the University of Alberta recently discovered they also contain antioxidant properties, which helps in the prevention of cardiovascular disease and cancer.
Jianping Wu, Andreas Schieber and graduate students Chamila Nimalaratne and Daise Lopes-Lutz of the U of A Department of Agricultural Food and Nutritional Science examined egg yolks produced by hens fed typical diets of either primarily wheat or corn. They found the yolks contained two amino acids, tryptophan and tyrosine, which have high antioxidant properties.
After analyzing the properties, the researchers determined that two egg yolks in their raw state have almost twice as many antioxidant properties as an apple and about the same as half a serving (25 grams) of cranberries.
However, when the eggs were fried or boiled, antioxidant properties were reduced by about half, and a little more than half if the eggs were cooked in a microwave.
"It's a big reduction but it still leaves eggs equal to apples in their antioxidant value," said Wu.
The findings were published in the peer-reviewed journal Food Chemistry.
The discovery of these two amino acids, while important, may only signify the beginning of finding antioxidant properties in egg yolks, said Wu, an associate professor of agricultural, food and nutritional science.
"Ultimately, we're trying to map antioxidants in egg yolks so we have to look at all of the properties in the yolks that could contain antioxidants, as well as how the eggs are ingested," said Wu, adding that he and his team will examine the other type of antioxidant already known to be in eggs, carotenoids, the yellow pigment in egg yolk, as well as peptides.
In previous research, Wu found that egg proteins were converted by enzymes in the stomach and small intestines and produced peptides that act the same way as ACE inhibitors, prescriptions drugs that are used to lower high blood pressure.
That finding defied common wisdom and contradicted the public perception that eggs increased high blood pressure because of their high cholesterol content. Additional research by Wu suggests the peptides can be formulated to help prevent and treat hypertension.
Wu is convinced the peptides also have some antioxidant properties, which leads him to suggest that when he completes the next step in his research, the result will likely be that eggs have more antioxidant properties than we currently know.
One of nature's most perfect foods may be even better for us than previously thought.
While eggs are well known to be an excellent source of proteins, lipids, vitamins and minerals, researchers at the University of Alberta recently discovered they also contain antioxidant properties, which helps in the prevention of cardiovascular disease and cancer.
Jianping Wu, Andreas Schieber and graduate students Chamila Nimalaratne and Daise Lopes-Lutz of the U of A Department of Agricultural Food and Nutritional Science examined egg yolks produced by hens fed typical diets of either primarily wheat or corn. They found the yolks contained two amino acids, tryptophan and tyrosine, which have high antioxidant properties.
After analyzing the properties, the researchers determined that two egg yolks in their raw state have almost twice as many antioxidant properties as an apple and about the same as half a serving (25 grams) of cranberries.
However, when the eggs were fried or boiled, antioxidant properties were reduced by about half, and a little more than half if the eggs were cooked in a microwave.
"It's a big reduction but it still leaves eggs equal to apples in their antioxidant value," said Wu.
The findings were published in the peer-reviewed journal Food Chemistry.
The discovery of these two amino acids, while important, may only signify the beginning of finding antioxidant properties in egg yolks, said Wu, an associate professor of agricultural, food and nutritional science.
"Ultimately, we're trying to map antioxidants in egg yolks so we have to look at all of the properties in the yolks that could contain antioxidants, as well as how the eggs are ingested," said Wu, adding that he and his team will examine the other type of antioxidant already known to be in eggs, carotenoids, the yellow pigment in egg yolk, as well as peptides.
In previous research, Wu found that egg proteins were converted by enzymes in the stomach and small intestines and produced peptides that act the same way as ACE inhibitors, prescriptions drugs that are used to lower high blood pressure.
That finding defied common wisdom and contradicted the public perception that eggs increased high blood pressure because of their high cholesterol content. Additional research by Wu suggests the peptides can be formulated to help prevent and treat hypertension.
Wu is convinced the peptides also have some antioxidant properties, which leads him to suggest that when he completes the next step in his research, the result will likely be that eggs have more antioxidant properties than we currently know.
Thursday, June 30, 2011
Red wine: Exercise in a bottle?
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New research in the FASEB Journal suggests that a daily intake of resveratrol prevents the ill effects of simulated weightlessness on muscle and bone metabolism
Bethesda, MD—As strange as it sounds, a new research study published in the FASEB Journal suggests that the "healthy" ingredient in red wine, resveratrol, may prevent the negative effects that spaceflight and sedentary lifestyles have on people. The report describes experiments in rats that simulated the weightlessness of spaceflight, during which the group fed resveratrol did not develop insulin resistance or a loss of bone mineral density, as did those who were not fed resveratrol.
According to Gerald Weissmann, M.D., Editor-in-Chief of the FASEB Journal, "There are overwhelming data showing that the human body needs physical activity, but for some of us, getting that activity isn't easy. A low gravity environment makes it nearly impossible for astronauts. For the earthbound, barriers to physical activity are equally challenging, whether they be disease, injury, or a desk job. Resveratrol may not be a substitute for exercise, but it could slow deterioration until someone can get moving again."
Scientists studied rats that underwent simulated weightlessness by hindlimb tail suspension and were given a daily oral load of resveratrol. The control group showed a decrease in soleus muscle mass and strength, the development of insulin resistance, and a loss of bone mineral density and resistance to breakage. The group receiving resveratrol showed none of these complications. Study results further demonstrated some of the underlying mechanisms by which resveratrol acts to prevent the wasting adaptations to disuse-induced mechanical unloading. This study also suggests that resveratrol may be able to prevent the deleterious consequences of sedentary behaviors in humans.
"If resveratrol supplements are not your cup of tea," Weissmann added, "then there's good news. You can find it naturally in red wine, making it the toast of the Milky Way."
New research in the FASEB Journal suggests that a daily intake of resveratrol prevents the ill effects of simulated weightlessness on muscle and bone metabolism
Bethesda, MD—As strange as it sounds, a new research study published in the FASEB Journal suggests that the "healthy" ingredient in red wine, resveratrol, may prevent the negative effects that spaceflight and sedentary lifestyles have on people. The report describes experiments in rats that simulated the weightlessness of spaceflight, during which the group fed resveratrol did not develop insulin resistance or a loss of bone mineral density, as did those who were not fed resveratrol.
According to Gerald Weissmann, M.D., Editor-in-Chief of the FASEB Journal, "There are overwhelming data showing that the human body needs physical activity, but for some of us, getting that activity isn't easy. A low gravity environment makes it nearly impossible for astronauts. For the earthbound, barriers to physical activity are equally challenging, whether they be disease, injury, or a desk job. Resveratrol may not be a substitute for exercise, but it could slow deterioration until someone can get moving again."
Scientists studied rats that underwent simulated weightlessness by hindlimb tail suspension and were given a daily oral load of resveratrol. The control group showed a decrease in soleus muscle mass and strength, the development of insulin resistance, and a loss of bone mineral density and resistance to breakage. The group receiving resveratrol showed none of these complications. Study results further demonstrated some of the underlying mechanisms by which resveratrol acts to prevent the wasting adaptations to disuse-induced mechanical unloading. This study also suggests that resveratrol may be able to prevent the deleterious consequences of sedentary behaviors in humans.
"If resveratrol supplements are not your cup of tea," Weissmann added, "then there's good news. You can find it naturally in red wine, making it the toast of the Milky Way."
Wednesday, June 29, 2011
Fidgeting your way to fitness
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Walking to the photocopier and fidgeting at your desk are contributing more to your cardiorespiratory fitness than you might think.
Researchers have found that both the duration and intensity of incidental physical activities (IPA) are associated with cardiorespiratory fitness. The intensity of the activity seems to be particularly important, with a cumulative 30-minute increase in moderate physical activity throughout the day offering significant benefits for fitness and long-term health.
“It’s encouraging to know that if we just increase our incidental activity slightly--a little bit more work around the house, or walking down the hall to speak with a co-worker as opposed to sending an email--we can really benefit our health in the long-term,” says Ashlee McGuire, the study’s lead researcher and a graduate student in the School of Kinesiology and Health Studies. “Best of all, these activities don’t take up a lot of time, they’re not difficult to do, and you don’t have to go to a gym.”
Ms McGuire and fellow researcher Robert Ross, a professor in the School of Kinesiology and Health Studies, define IPA as non-purposeful physical activity accrued through activities of daily living, such as doing housework, climbing stairs or walking around the office.
Walking to the photocopier and fidgeting at your desk are contributing more to your cardiorespiratory fitness than you might think.
Researchers have found that both the duration and intensity of incidental physical activities (IPA) are associated with cardiorespiratory fitness. The intensity of the activity seems to be particularly important, with a cumulative 30-minute increase in moderate physical activity throughout the day offering significant benefits for fitness and long-term health.
“It’s encouraging to know that if we just increase our incidental activity slightly--a little bit more work around the house, or walking down the hall to speak with a co-worker as opposed to sending an email--we can really benefit our health in the long-term,” says Ashlee McGuire, the study’s lead researcher and a graduate student in the School of Kinesiology and Health Studies. “Best of all, these activities don’t take up a lot of time, they’re not difficult to do, and you don’t have to go to a gym.”
Ms McGuire and fellow researcher Robert Ross, a professor in the School of Kinesiology and Health Studies, define IPA as non-purposeful physical activity accrued through activities of daily living, such as doing housework, climbing stairs or walking around the office.
MAKE BLADDER CANCER CELLS MORE SUSCEPTIBLE TO CHEMOTHERAPY
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Improving efficacy of drugs would boost post-surgery survivorship
Researchers at the UC Davis Cancer Center have discovered a way of sensitizing muscle-invasive bladder cancer cells so that they succumb to the toxic effects of chemotherapy. The finding adds to mounting evidence that tiny strands of RNA — called microRNA — play key roles in some of the deadliest types of cancer.
In the current study, published online June 28 in International Journal of Cancer, researchers boosted the production of a microRNA found in bladder cancer cell lines — encoded for by the gene miR-34a — and found that this resulted in more of the cells being killed by cisplatin, a chemotherapy drug used to treat many types of cancer.
Ralph deVere White
"When we took the bladder cancer cell lines and activated miR-34a, they were more responsive to chemotherapy," said Ralph deVere White, UC Davis Cancer Center director and professor of urology.
The study establishes, for the first time, a link between sensitivity of bladder cancer cells to chemotherapy and the expression of miR-34a. It suggests that miR-34a may be used as a predictor of response to chemotherapy, as well as a target for new drugs.
Currently, about 50 percent of patients with advanced bladder cancer will survive five years after diagnosis. Although clinical trials have demonstrated that chemotherapy before surgery can improve survival rates, it is rarely used because fewer than 50 percent of patients will respond favorably. Without knowing which patients will improve as a result of chemotherapy, physicians are generally reluctant to use a treatment that can cause their patients to suffer significant side effects.
"So, now we have to prove that it works to predict chemotherapy response in patients," deVere White said. To that end, UC Davis has entered into a partnership with Israel-based Rosetta Genomics to develop a microRNA profile for muscle-invasive bladder cancer that may be used to predict response to chemotherapy.
As part of the current study, deVere White and his colleagues studied 27 patients and found that many who expressed lower levels of miR-34a subsequently did not respond to the combined chemotherapy-surgery treatment. Because the finding was not statistically significant, however, further work in this area is needed.
The team also studied tumor samples taken from eight of the patients who did not respond to chemotherapy. They compared the expression of miR-34a before and after chemotherapy.
"We wanted to see, if you looked at the patient's tissue before chemotherapy, were there differentially expressed microRNAs in the patients who responded to the drugs versus those that didn't respond," deVere White explained.
The team found that expression of miR-34a increased after treatment in only two of the eight cases, suggesting that gene expression levels remained low during treatment and confirming the link between low gene expression and failure to respond to treatment.
"The combined data indicate that the elevation of miR-34a expression levels prior to chemotherapy would be of benefit to muscle-invasive bladder cancer patients, particularly in a setting of low mi-R-34a expression," the authors write.
Since their discovery in 1993, microRNAs have been found to be involved in a number of types of cancer, heart disease and diseases of the nervous system. In 2007, deVere White was part of a team that identified miR-125b, a gene that encodes for a microRNA that jump starts prostate cancer cell growth midway through the disease process, eventually causing it to become fatal.
The microRNA studied here was also recently found to play a role in medulloblastoma, an aggressive type of brain cancer. MicroRNAs, which are usually 22 to 33 nucleotides in length, are known as post-transcriptional regulators. That means they work by turning genes on or off during the part of the protein synthesis process that involves making a strand of RNA from a DNA template. The human genome encodes for an estimated 1,000 microRNAs.
According to the authors, future studies involving miR-34a will focus on testing its ability to increase sensitivity to chemotherapy and analysis of miR-34a expression in patients with muscle-invasive bladder cancer. With the currently low chemotherapy success rate and poor five-year survival rate for patients with this disease, "such studies are clearly warranted," the authors write.
"If we can prove what is causing chemotherapy resistance in patients with muscle-invasive bladder cancer, American ingenuity will come up with ways to overcome it," predicted deVere White.
Improving efficacy of drugs would boost post-surgery survivorship
Researchers at the UC Davis Cancer Center have discovered a way of sensitizing muscle-invasive bladder cancer cells so that they succumb to the toxic effects of chemotherapy. The finding adds to mounting evidence that tiny strands of RNA — called microRNA — play key roles in some of the deadliest types of cancer.
In the current study, published online June 28 in International Journal of Cancer, researchers boosted the production of a microRNA found in bladder cancer cell lines — encoded for by the gene miR-34a — and found that this resulted in more of the cells being killed by cisplatin, a chemotherapy drug used to treat many types of cancer.
Ralph deVere White
"When we took the bladder cancer cell lines and activated miR-34a, they were more responsive to chemotherapy," said Ralph deVere White, UC Davis Cancer Center director and professor of urology.
The study establishes, for the first time, a link between sensitivity of bladder cancer cells to chemotherapy and the expression of miR-34a. It suggests that miR-34a may be used as a predictor of response to chemotherapy, as well as a target for new drugs.
Currently, about 50 percent of patients with advanced bladder cancer will survive five years after diagnosis. Although clinical trials have demonstrated that chemotherapy before surgery can improve survival rates, it is rarely used because fewer than 50 percent of patients will respond favorably. Without knowing which patients will improve as a result of chemotherapy, physicians are generally reluctant to use a treatment that can cause their patients to suffer significant side effects.
"So, now we have to prove that it works to predict chemotherapy response in patients," deVere White said. To that end, UC Davis has entered into a partnership with Israel-based Rosetta Genomics to develop a microRNA profile for muscle-invasive bladder cancer that may be used to predict response to chemotherapy.
As part of the current study, deVere White and his colleagues studied 27 patients and found that many who expressed lower levels of miR-34a subsequently did not respond to the combined chemotherapy-surgery treatment. Because the finding was not statistically significant, however, further work in this area is needed.
The team also studied tumor samples taken from eight of the patients who did not respond to chemotherapy. They compared the expression of miR-34a before and after chemotherapy.
"We wanted to see, if you looked at the patient's tissue before chemotherapy, were there differentially expressed microRNAs in the patients who responded to the drugs versus those that didn't respond," deVere White explained.
The team found that expression of miR-34a increased after treatment in only two of the eight cases, suggesting that gene expression levels remained low during treatment and confirming the link between low gene expression and failure to respond to treatment.
"The combined data indicate that the elevation of miR-34a expression levels prior to chemotherapy would be of benefit to muscle-invasive bladder cancer patients, particularly in a setting of low mi-R-34a expression," the authors write.
Since their discovery in 1993, microRNAs have been found to be involved in a number of types of cancer, heart disease and diseases of the nervous system. In 2007, deVere White was part of a team that identified miR-125b, a gene that encodes for a microRNA that jump starts prostate cancer cell growth midway through the disease process, eventually causing it to become fatal.
The microRNA studied here was also recently found to play a role in medulloblastoma, an aggressive type of brain cancer. MicroRNAs, which are usually 22 to 33 nucleotides in length, are known as post-transcriptional regulators. That means they work by turning genes on or off during the part of the protein synthesis process that involves making a strand of RNA from a DNA template. The human genome encodes for an estimated 1,000 microRNAs.
According to the authors, future studies involving miR-34a will focus on testing its ability to increase sensitivity to chemotherapy and analysis of miR-34a expression in patients with muscle-invasive bladder cancer. With the currently low chemotherapy success rate and poor five-year survival rate for patients with this disease, "such studies are clearly warranted," the authors write.
"If we can prove what is causing chemotherapy resistance in patients with muscle-invasive bladder cancer, American ingenuity will come up with ways to overcome it," predicted deVere White.
Diet Soft Drink Consumption Is Associated with Increased Waist Circumference
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Consumption of diet soft drinks (DSDs) has been linked to increased incidence of obesity, metabolic syndrome, and diabetes. The authors examined the relationship between DSD consumption and long-term change in waist circumference (ΔWC) in 474 participants, aged 65-74 yrs at baseline, in the San Antonio Longitudinal Study of Aging (SALSA). Overall, DSD users experienced 70% greater increases in WC compared with non-users.
Measures of height, weight, waist circumference (WC), and DSD intake were recorded at baseline and at each of 3 follow-up exams, for an average follow-up interval of 3.6 yrs (9.5 yrs total). Using repeated-measures ANCOVA, we compared mean ΔWC for DSD users vs. non-users in all follow-up periods, adjusted for sex; baseline WC, age, ethnicity, education, neighborhood, leisure physical activity, diabetes and smoking status; and length of follow-up.
WC is widely used as a proxy measure of visceral adiposity, a major risk factor for diabetes, cardiovascular disease, cancer, and other chronic conditions. These results suggest that – amidst the national drive to reduce consumption of sugar-sweetened drinks – policies which would promote the consumption of DSDs may have unintended deleterious effects. Data from this and other prospective studies suggest that the promotion of diet sodas as healthy alternatives may be ill-advised: they may be free of calories, but not of consequences.
Consumption of diet soft drinks (DSDs) has been linked to increased incidence of obesity, metabolic syndrome, and diabetes. The authors examined the relationship between DSD consumption and long-term change in waist circumference (ΔWC) in 474 participants, aged 65-74 yrs at baseline, in the San Antonio Longitudinal Study of Aging (SALSA). Overall, DSD users experienced 70% greater increases in WC compared with non-users.
Measures of height, weight, waist circumference (WC), and DSD intake were recorded at baseline and at each of 3 follow-up exams, for an average follow-up interval of 3.6 yrs (9.5 yrs total). Using repeated-measures ANCOVA, we compared mean ΔWC for DSD users vs. non-users in all follow-up periods, adjusted for sex; baseline WC, age, ethnicity, education, neighborhood, leisure physical activity, diabetes and smoking status; and length of follow-up.
WC is widely used as a proxy measure of visceral adiposity, a major risk factor for diabetes, cardiovascular disease, cancer, and other chronic conditions. These results suggest that – amidst the national drive to reduce consumption of sugar-sweetened drinks – policies which would promote the consumption of DSDs may have unintended deleterious effects. Data from this and other prospective studies suggest that the promotion of diet sodas as healthy alternatives may be ill-advised: they may be free of calories, but not of consequences.
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