Plasma chain-breaking antioxidants in Alzheimer's disease, vascular dementia and Parkinson's disease.
(9/2124)
We studied the plasma chain-breaking antioxidants alpha carotene, beta carotene, lycopene, Vitamin A, Vitamin C, Vitamin E and a measure of total antioxidant capacity, TAC, in 79 patients with Alzheimer's disease (AD), 37 patients with vascular dementia (VaD), 18 patients with Parkinson's disease and dementia (PDem), and 58 matching controls, together with 41 patients with Parkinson's disease (PD) and 41 matching controls. Significant reductions in individual antioxidants were observed in all dementia groups. When compared to controls, the following were reduced: Vitamin A in AD (p < 0.01) and VaD (p < 0.001); Vitamin C in AD (p < 0.001), VaD (p < 0.001) and PDem (p < 0.01); Vitamin E in AD (p < 0.01) and VaD (p < 0.001); beta carotene in VaD (p = 0.01); lycopene in PDem (p < 0.001). Lycopene was also reduced in PDem compared to AD (p < 0.001) and VaD (p < 0.001). Antioxidant levels in PD were not depleted. No significant change in TAC was seen in any group. The reduction in plasma chain-breaking antioxidants in patients with dementia may reflect an increased free-radical activity, and a common role in cognitive impairment in these conditions. Increased free-radical activity in VaD and PDem could be associated with concomitant AD pathology. Individual antioxidant changes are not reflected in TAC. (+info)
Antioxidant intake and risk of incident age-related nuclear cataracts in the Beaver Dam Eye Study.
(10/2124)
The relation of antioxidant nutrients to the incidence of nuclear cataracts was investigated in a cohort of adults aged 43-84 years in the Beaver Dam Eye Study (Beaver Dam, Wisconsin). Nuclear opacity was assessed on a five-point ordinal scale using lens photographs taken at baseline (1988-1990) and at follow-up (1993-1995). Of the 1,354 persons eligible, 246 developed a nuclear cataract (level 4 or 5 opacity) in at least one eye. Antioxidant intakes were assessed using a food frequency questionnaire administered at baseline for time points corresponding to intake during the year preceding baseline and 10 years before baseline (the distant past). Lutein-zeaxanthin was the only carotenoid, out of five examined, that was associated with nuclear cataracts. Persons in the highest quintile of lutein intake in the distant past were half as likely to have an incident cataract as persons in the lowest quintile of intake (95% confidence interval 0.3-0.8). In the overall group, nuclear cataracts were not significantly related to intake of vitamin C or vitamin E. However, vitamins C and E were inversely associated with opacities in persons who had some other risk factors for cataracts. While results of this short term follow-up study are consistent with a possible protective influence of lutein and vitamins E and C on the development of nuclear cataracts, the evidence in the present study provides weak support for these associations. (+info)
Hyperhomocysteinemia and hypofibrinolysis in young adults with ischemic stroke.
(11/2124)
BACKGROUND AND PURPOSE: Data from epidemiological and case-control studies suggest that increased total homocysteine (tHcy) levels are associated with increased risk for thromboembolic disease. The mechanisms by which hyperhomocysteinemia contributes to thrombogenesis are incompletely understood. The main objectives of this study of young ischemic stroke patients were (1) to examine fasting and post-methionine load levels of tHcy, (2) to ascertain the genotype frequency of the C677CT mutation in the methylenetetrahydrofolate reductase gene (TT genotype), and (3) to study the possible interaction between plasma tHcy levels and fibrinolytic factors. METHODS: This case-control study was based on 80 consecutive patients aged 18 to 44 years admitted between January 1992 and May 1996 as a result of a first-ever ischemic stroke. Forty-one healthy control subjects were recruited. Measurement of fasting tHcy and post-methionine load levels and evaluation of the fibrinolytic system were undertaken at least 3 months (mean, 5.1+/-1. 9 months) after admission. Genotyping of the methylenetetrahydrofolate reductase gene was performed. RESULTS: Although the increase after methionine loading (ie, postload tHcy minus fasting-level tHcy) was significantly higher among patients, there was no difference in fasting and postload tHcy levels. After adjustment for conventional risk factors, elevated postload increase tHcy levels were associated with a 4.8-fold increased risk of ischemic stroke. There was no difference between patients and control subjects in either TT genotype frequency or T allele frequency. Abnormal response to methionine loading was associated with higher tissue plasminogen activator (tPA) mass concentration, higher plasminogen activator inhibitor-1 levels, and lower tPA activity. After adjustment for age, sex, body mass index, serum cholesterol, and triglycerides, an abnormal increase in postload tHcy levels remained significantly associated with tPA mass concentration levels (P=0.03). CONCLUSIONS: A moderately elevated increase in tHcy levels after methionine loading was associated with an increased risk for ischemic stroke in young adults. In contrast, fasting tHcy levels did not differ between patients and controls. A moderately elevated increase in tHcy after methionine loading may provide a additional thrombogenic risk mediated in part by interactions with the fibrinolytic system. In young stroke patients, a methionine loading test to detect hyperhomocysteinemia should always be considered in the convalescent phase of the disease. (+info)
Dietary antioxidants and magnesium in type 1 brittle asthma: a case control study.
(12/2124)
BACKGROUND: Type 1 brittle asthma is a rare form of asthma. Atopy, psychosocial factors and diet may contribute to this condition. As increased dietary magnesium has a beneficial effect on lung function and selenium, vitamins A, C and E have antioxidant properties, a study was undertaken to test the hypothesis that patients with brittle asthma have diets deficient in these nutrients compared with subjects with non-brittle asthma and healthy adults. METHODS: A case control study of the dietary intakes of 20 subjects with brittle asthma, 20 with non-brittle asthma, and 20 healthy adults was performed using five day weighed dietary records. Intake of magnesium was the primary outcome measure with selenium and vitamins A, C and E as secondary outcomes. Serum levels were measured at the same time as the dietary assessment. RESULTS: Sixty subjects (27 men) of mean age 49.5 years were recruited and completed the study. Subjects with brittle asthma had statistically lower median dietary intakes of vitamins A and E than the other groups (vitamin A: brittle asthma 522.5 micrograms/day, non-brittle asthma 869.5 micrograms/day, healthy adults 806.5 micrograms/day; vitamin E: brittle asthma 4.3 mg/day, non-brittle asthma 4.6 mg/day, healthy adults 4.5 mg/day). Median dietary intakes for the other nutrients were not significantly different between groups. Serum levels were within normal ranges for each nutrient in all subjects. Intakes less than the reference nutrient intake (RNI) for magnesium and vitamins A and C, and less than the safe intake (SI) for vitamin E were more likely in patients with brittle asthma than in those with non-brittle asthma. CONCLUSION: Nutrient deficiency and reduced antioxidant activity may contribute to disease activity in type 1 brittle asthma, although a prospective study of replacement therapy will be needed to confirm this hypothesis. (+info)
New federal office will spend millions to regulate herbal remedies, vitamins.
(13/2124)
The new Office of Natural Health Products promises better regulation of herbal remedies, but its creation raises many questions. (+info)
Interaction of cattle health/immunity and nutrition.
(14/2124)
The usual means of assessing the health of newly received beef cattle susceptible to bovine respiratory disease (BRD) are subjective, typically involving visual evaluation aided by minimal clinical measurements. Recent evidence based on the occurrence of pneumonic lung lesions at slaughter indicates a need for more accurate methods of diagnosing BRD. Inadequate passive immune transfer at birth may be an important risk factor in susceptibility to BRD, suggesting the need for management to improve passive transfer success rates. Preweaning management and vaccination practices offer opportunities for beef cattle producers to improve the immune status of newly weaned calves and decrease postweaning BRD. Feeding diets with higher levels of concentrate typically improves performance by newly weaned or received cattle, as does feeding diets supplemented with protein; however, limited data suggest that increasing concentrate and protein in receiving diets increases the rate and severity of subjectively determined BRD morbidity. Research with receiving diet concentrate/protein level relative to humoral and cell-mediated immune function coupled with indicators of health and performance is needed. Supplemental B vitamins are sometimes useful in receiving diets, but the effects have been variable, presumably reflecting differences in stress and associated feed intake responses. Vitamin E added to receiving diets to supply > or = 400 IU/animal daily seems beneficial for increasing gain and decreasing BRD morbidity; however, further dose titration experiments are needed. Supplemental Zn, Cu, Se, and Cr can alter immune function of newly received calves, and some field trials have shown decreases in BRD morbidity rate with supplementation; however, several experiments have shown no performance or health/immune benefits from supplementation of these trace minerals. Formulation of receiving diets should take into account decreased feed intake by highly stressed, newly received beef cattle and known nutrient deficiencies, but fortification of such diets with trace minerals beyond the levels needed to compensate for these effects is difficult to justify from present data. (+info)
Parenteral vitamin requirements during intravenous feeding.
(15/2124)
Serum vitamin levels of 40 patients undergoing parenteral nutrition over a 5-to 42-day period were studied while the subjects received daily water-soluble and once weekly fat soluble vitamin formulations intravenously. Initial serum deficiencies of vitamins A, C, and folate were noted in a large portion of the severely malnourished population. At the replacement levels used in this study a small number of patients developed subnormal levels of vitamins A and D. Improvement in levels for vitamin C and folate were noted for most patients. Vitamin B12 deficiencies were not noted in any patient. Currently available commercial vitamin preparations can be used with safety in the parenterally nourished population and recommended guidelines for weekly infusion of both water and fat soluble vitamins are presented. (+info)
The role of oxidative stress in atherosclerosis: the hope and the hype.
(16/2124)
Numerous lines of investigation support the importance of oxidative stress in the development of atherosclerosis. Results from studies in isolated cells and in animal models of atherosclerosis are compelling, as are those from a select number of clinical trials. Unfortunately, the results of prospective, randomized clinical studies have been disappointing and may reflect our current inability to accurately assess oxidative risk and the response to antioxidant therapy. Only when it is possible to accurately and easily measure oxidative stress will it be possible to accurately determine the efficacy of different antioxidant approaches. (+info)