Critical Research is a regular feature in Naturopathy Digest. Each month, we provide abstracts from studies published in the top peer-reviewed journals; each abstract includes the complete citation and an online link to the journal. Whenever possible, this link directs you to a page where you can order the full text of the study, if desired.
This Month's Featured Abstract
Fruit and Vegetable Juices Linked to Delayed Onset of Alzheimer's Disease
Qi Dai, MD, PhD, Amy R. Borenstein, PhD, Yougui Wu, PhD, James C. Jackson, PsyD, Eric B. Larson, MD, MPH
Background: Growing evidence suggests that oxidative damage caused by the β-amyloid peptide in the pathogenesis of Alzheimer's disease may be hydrogen peroxide- mediated. Many polyphenols, the most abundant dietary antioxidants, possess stronger neuroprotection against hydrogen peroxide than antioxidant vitamins.
Methods: We tested whether consumption of fruit and vegetable juices, containing a high concentration of polyphenols, decreases the risk of incident-probable Alzheimer's disease in the Kame Project cohort, a population-based prospective study of 1836 Japanese Americans in King County, Washington, who were dementia-free at baseline (1992-1994) and were followed through 2001.
Results: After adjustment for potential confounders, the hazard ratio for probable Alzheimer's disease was 0.24 (95% confidence interval [CI], 0.09-0.61) comparing subjects who drank juices at least 3 times per week with those who drank less than once per week with a hazard ratio of 0.84 (95% CI, 0.31-2.29) for those drinking juices 1 to 2 times per week (P for trend < .01). This inverse association tended to be more pronounced among those with an apolipoprotein E-4 allele and those who were not physically active. Conversely, no association was observed for dietary intake of vitamins E, C, or β-carotene or tea consumption.
Conclusions: Fruit and vegetable juices may play an important role in delaying the onset of Alzheimer's disease, particularly among those who are at high risk for the disease.
The use of a Cissus quadrangularis formulation in the management of weight loss and metabolic syndrome.
Julius Oben, Dieudonne Kuate, Gabriel Agbor, Claudia Momo, Xavio Talla
Methods: The study was a randomized, double-blind, placebo-controlled design involving 123 overweight and obese persons (47.2% male; 52.8% female; ages 19 to 50). The 92 obese (BMI >30) participants were randomized into three groupsplacebo, formulation/no diet, and formulation/diet (2100 to 2200 calories/day). The 31 overweight participants (BMI = 25 to 29) formed a fourth (no diet) treatment group. All participants received two daily doses of the formulation or placebo and remained on a normal or calorie-controlled diet for 8 weeks.
Results: At the end of the trial period, statistically significant net reductions in weight and central obesity, as well as in fasting blood glucose, total cholesterol, LDL-cholesterol, triglycerides, and C-reactive protein were observed in participants who received the formulation, regardless of diet.
Conclusion: Cissus quadrangularis formulation appears to be useful in the management of weight loss and metabolic syndrome.
Factors influencing consumer dietary health preventative behaviours.
Dan A. Petrovici and Christopher Ritson
Background: The deterioration of the health status of the Romanian population during the economic transition from a centrally planned to a free market economy has been linked to lifestyle factors (e.g., diet) regarded as main determinants of the disparity in life expectancy between Eastern and Western Europe. Reforms in the health care system in this transition economy aim the focus on preventive action. The purpose of this study was to identify the factors that impact on the individual decision to engage in Dietary Health Preventive Behaviour (DHPB) and investigate their influence in the context of a health cognition model.
Methods: A population-based study recruited 485 adult respondents using stratified random sampling and face-to-face interviews.
Results: Respondents' health motivation, beliefs that diet can prevent disease, knowledge about nutrition and age were found significant predictors of DHPB. The information acquisition behaviour (frequency of reading nutrition information from labels) was positively predicted by health motivation, education, self-reported knowledge about nutrition and negatively by age. A significant share of respondents believed they are not susceptible to the elicited diseases. Health promotion strategies should aim to change the judgments of health risk.
Conclusions: The variables of the Theory of HPB represented a valid framework of predicting DHPB. The insignificance of perceived threat of disease on DHPB may suggest that, under an income constraint, consumers tend to trade off long-term health benefits for short-term benefits. This cautions against the use of negative messages in public health campaigns. Raising the awareness of diet-disease relationships, knowledge about nutrition (particularly sources and risks associated with dietary fat and cholesterol) may induce people to adopt preventive dietary habits.
Influence of high-carbo-hydrate mixed meals with different glycemic indexes on substrate utilization during subsequent exercise in women.
Emma J Stevenson, Clyde Williams, Laura E Mash, Beth Phillips and Maria L Nute
Background: Few data exist on the metabolic responses to mixed meals with different glycemic indexes and their effects on substrate metabolism during exercise in women.
Objective: We examined the effects of pre-exercise mixed meals providingcarbohydrates with high (HGI) or low glycemic index (LGI) on substrate utilization during rest and exercise in women.
Design: Eight healthy, active, eumenorrheic women [aged 18.60.9 y; body mass: 59.97.1 kg; maximal oxygen uptake (O2max): 48.71.1 mL kg-1 min-1] completed 2 trials. On each occasion, subjects were provided with a test breakfast 3 h before performing a 60-min run at 65% O2max on a motorized treadmill. Both breakfasts provided 2gcarbohydrate/kg body mass and were isoenergetic. The calculated GIs of the meals were 78 (HGI) and 44 (LGI).
Results: Peak plasma glucose and serum insulin concentrations were greater after the HGI breakfast than after the LGI breakfast (P < 0.05). No significant differences in substrate oxidation were reported throughout the postprandial period. During exercise, the estimated rate of fat oxidation was greater in the LGI trial than in the HGI trial (P < 0.05). Similarly, plasma-free fatty acid and glycerol concentrations were higher throughout exercise in the LGI trial (P < 0.05). No significant differences in plasma glucose or serum insulin were observed during exercise.
Conclusion: Altering the GI of the carbohydrate within a meal significantly changes the postprandial hyperglycemic and hyperinsulinemic responses in women. A LGI pre-exercise meal resulted in a higher rate of fat oxidation during exercise than did an HGI meal.
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Date Last Modified - Friday, 17-Oct-2008 12:10:51 PDT