Post by NIKKIB on Sept 6, 2006 20:24:19 GMT 1
From Medscape: August 31, 2006 -
Fruit and vegetable juices may delay the onset of Alzheimer's disease (AD), according to the results of a study reported in the September issue of the American Journal of Medicine."Growing evidence suggests that oxidative damage caused by the beta-amyloid peptide in the pathogenesis of AD may be hydrogen peroxide-mediated," write Qi Dai, MD, from Vanderbilt School of Medicine in Virginia, and colleagues.
"Many polyphenols, the most abundant dietary antioxidants, possess stronger neuroprotection against hydrogen peroxide than antioxidant vitamins." The Kame Project is a population-based prospective study of 1836 Japanese Americans in King County, Washington, who were dementia-free at baseline (1992 - 1994) and were followed up through 2001. Comparing subjects who drank juices at least 3 times per week with those who drank juices less often than once per week, the hazard ratio (HR) for probable AD was 0.24 (95% confidence interval [CI], 0.09 - 0.61), after adjustment for potential confounders. For those drinking juices 1 to 2 times per week, the HR was 0.84 (95% CI, 0.31 - 2.29; P for trend < .01).
This inverse association was more apparent in subjects with an apolipoprotein E epsilon-4 allele and in those who were not physically active. No associations were observed for dietary intake of vitamins E, C, or beta-carotene or tea consumption.
"Fruit and vegetable juices may play an important role in delaying the onset of AD, particularly among those who are at high risk for the disease," the authors write. "These results may lead to a new avenue of inquiry in the prevention of AD." Study limitations include possible residual confounding, somewhat limited sample size, and lack of intake information on each specific type of juice.
"Future studies are necessary to confirm our findings and to investigate how intake of different fruit and vegetable juices relate to the risk of AD," the authors conclude. Am J Med. 2006;119:751-759.
Learning Objectives for This Educational ActivityUpon completion of this activity, participants will be able to: a.. Identify the effect of donepezil and vitamin E supplements in the prevention of progression of mild cognitive impairment to AD. b.. Describe the effects of fruit juice and dietary antioxidant intake on the risk for AD.
Clinical ContextMany studies have examined the pathophysiology of AD and how to prevent its devastating effects. In a trial by Petersen and colleagues of 769 patients with the amnestic subtype of mild cognitive impairment, vitamin E at a dose of 2000 IU daily failed to reduce the overall rate of progression to AD when compared with placebo for a 3-year treatment period. The results, which were published in the June 9, 2005, issue of The New England Journal of Medicine, also demonstrated that donepezil at a dose of 10 mg daily similarly failed to reduce the overall rate of progression to AD, but it did reduce the progression to AD at 1 year compared with placebo.
Also, donepezil had a significant effect on the 3-year risk for AD among the subset of participants with the apolipoprotein E epsilon-4 allele. Polyphenols are antioxidants that may be lost in food processing but are present in juices.
The authors of the current study perform a retrospective analysis to determine whether fruit and vegetable juice intake might independently reduce the risk for AD. Study Highlights
a.. Study participants were drawn from the Kame Project, a study of dementia among Japanese populations living in Japan and the United States. All participants in the current analysis were aged 65 years or older at recruitment and lived in Washington State.
b.. Baseline cognitive screening was performed between 1992 and 1994, and at-risk scores prompted more specific studies for the presence and type of dementia. Dietary assessment was accomplished through the use of food frequency questionnaires at baseline.
c.. The main study outcome was the relationship between the consumption of antioxidants, particularly fruit and vegetable juices, and the risk for incident AD. The authors divided tea, wine, and juice consumption into 3 tertiles for statistical analysis, and these tertiles corresponded with consumption less than once per week, once or twice per week, and at least 3 times weekly.
Study results were adjusted to account for possible confounders, including tobacco use, alcohol use, age, total fat intake, educational level, physical activity, and apolipoprotein E status. The authors also adjusted results for baseline cognitive scores and olfactory dysfunction, which may signal the advent of a progressive neurologic disorder.
d.. 1589 subjects provided data for analysis. The mean age at enrollment was 71.8 years, and 54.4% of the cohort was women.
e.. Participants who drank juices had lower intakes of total fat and had a higher dietary intake of vitamin C compared with subjects who drank less juice. Juice drinkers were also more physically active and were more likely to be nonsmokers, have hypertension, and did not have the apolipoprotein E epsilon-4 allele.
f.. Consumption of tea did not affect the risk for AD.
g.. While there was a trend toward lower risk for AD with higher consumption of wine, few participants were wine drinkers, rendering this result as statistically insignificant.
h.. Drinking juice significantly reduced the risk for AD, with the highest tertile of juice consumption experiencing a HR of 0.24 vs the lowest tertile after adjustment for confounders and dietary antioxidant consumption. However, drinking juice once or twice weekly and dietary consumption of vitamins E, C, and beta-carotene did not significantly affect the risk for AD.
i.. Juice consumption appeared particularly effective in reducing the risk for AD among participants with physical inactivity, a history of tobacco use, and among carriers of the apolipoprotein E epsilon-4 allele.Pearls for Practice
a.. Previous research suggests that vitamin E supplements are not helpful in reducing the risk for progression from mild cognitive impairment to AD, and donepezil may be effective only for carriers of the apolipoprotein E epsilon-4 allele.
b.. In the current study, drinking fruit and vegetable juices at least 3 times weekly was associated with a reduced risk for AD among older Japanese Americans, while lower levels of juice consumption, tea consumption, and wine consumption were not protective.
Fruit and vegetable juices may delay the onset of Alzheimer's disease (AD), according to the results of a study reported in the September issue of the American Journal of Medicine."Growing evidence suggests that oxidative damage caused by the beta-amyloid peptide in the pathogenesis of AD may be hydrogen peroxide-mediated," write Qi Dai, MD, from Vanderbilt School of Medicine in Virginia, and colleagues.
"Many polyphenols, the most abundant dietary antioxidants, possess stronger neuroprotection against hydrogen peroxide than antioxidant vitamins." The Kame Project is a population-based prospective study of 1836 Japanese Americans in King County, Washington, who were dementia-free at baseline (1992 - 1994) and were followed up through 2001. Comparing subjects who drank juices at least 3 times per week with those who drank juices less often than once per week, the hazard ratio (HR) for probable AD was 0.24 (95% confidence interval [CI], 0.09 - 0.61), after adjustment for potential confounders. For those drinking juices 1 to 2 times per week, the HR was 0.84 (95% CI, 0.31 - 2.29; P for trend < .01).
This inverse association was more apparent in subjects with an apolipoprotein E epsilon-4 allele and in those who were not physically active. No associations were observed for dietary intake of vitamins E, C, or beta-carotene or tea consumption.
"Fruit and vegetable juices may play an important role in delaying the onset of AD, particularly among those who are at high risk for the disease," the authors write. "These results may lead to a new avenue of inquiry in the prevention of AD." Study limitations include possible residual confounding, somewhat limited sample size, and lack of intake information on each specific type of juice.
"Future studies are necessary to confirm our findings and to investigate how intake of different fruit and vegetable juices relate to the risk of AD," the authors conclude. Am J Med. 2006;119:751-759.
Learning Objectives for This Educational ActivityUpon completion of this activity, participants will be able to: a.. Identify the effect of donepezil and vitamin E supplements in the prevention of progression of mild cognitive impairment to AD. b.. Describe the effects of fruit juice and dietary antioxidant intake on the risk for AD.
Clinical ContextMany studies have examined the pathophysiology of AD and how to prevent its devastating effects. In a trial by Petersen and colleagues of 769 patients with the amnestic subtype of mild cognitive impairment, vitamin E at a dose of 2000 IU daily failed to reduce the overall rate of progression to AD when compared with placebo for a 3-year treatment period. The results, which were published in the June 9, 2005, issue of The New England Journal of Medicine, also demonstrated that donepezil at a dose of 10 mg daily similarly failed to reduce the overall rate of progression to AD, but it did reduce the progression to AD at 1 year compared with placebo.
Also, donepezil had a significant effect on the 3-year risk for AD among the subset of participants with the apolipoprotein E epsilon-4 allele. Polyphenols are antioxidants that may be lost in food processing but are present in juices.
The authors of the current study perform a retrospective analysis to determine whether fruit and vegetable juice intake might independently reduce the risk for AD. Study Highlights
a.. Study participants were drawn from the Kame Project, a study of dementia among Japanese populations living in Japan and the United States. All participants in the current analysis were aged 65 years or older at recruitment and lived in Washington State.
b.. Baseline cognitive screening was performed between 1992 and 1994, and at-risk scores prompted more specific studies for the presence and type of dementia. Dietary assessment was accomplished through the use of food frequency questionnaires at baseline.
c.. The main study outcome was the relationship between the consumption of antioxidants, particularly fruit and vegetable juices, and the risk for incident AD. The authors divided tea, wine, and juice consumption into 3 tertiles for statistical analysis, and these tertiles corresponded with consumption less than once per week, once or twice per week, and at least 3 times weekly.
Study results were adjusted to account for possible confounders, including tobacco use, alcohol use, age, total fat intake, educational level, physical activity, and apolipoprotein E status. The authors also adjusted results for baseline cognitive scores and olfactory dysfunction, which may signal the advent of a progressive neurologic disorder.
d.. 1589 subjects provided data for analysis. The mean age at enrollment was 71.8 years, and 54.4% of the cohort was women.
e.. Participants who drank juices had lower intakes of total fat and had a higher dietary intake of vitamin C compared with subjects who drank less juice. Juice drinkers were also more physically active and were more likely to be nonsmokers, have hypertension, and did not have the apolipoprotein E epsilon-4 allele.
f.. Consumption of tea did not affect the risk for AD.
g.. While there was a trend toward lower risk for AD with higher consumption of wine, few participants were wine drinkers, rendering this result as statistically insignificant.
h.. Drinking juice significantly reduced the risk for AD, with the highest tertile of juice consumption experiencing a HR of 0.24 vs the lowest tertile after adjustment for confounders and dietary antioxidant consumption. However, drinking juice once or twice weekly and dietary consumption of vitamins E, C, and beta-carotene did not significantly affect the risk for AD.
i.. Juice consumption appeared particularly effective in reducing the risk for AD among participants with physical inactivity, a history of tobacco use, and among carriers of the apolipoprotein E epsilon-4 allele.Pearls for Practice
a.. Previous research suggests that vitamin E supplements are not helpful in reducing the risk for progression from mild cognitive impairment to AD, and donepezil may be effective only for carriers of the apolipoprotein E epsilon-4 allele.
b.. In the current study, drinking fruit and vegetable juices at least 3 times weekly was associated with a reduced risk for AD among older Japanese Americans, while lower levels of juice consumption, tea consumption, and wine consumption were not protective.