Tuesday, November 28, 2006

News from the world of Nutritional Medicine

Topic: Exercising Regularly May Help Prevent Colds
Keywords: COMMON COLD, UPPER RESPIRATORY TRACT INFECTION - Exercise, Physical Activity, Postmenopausal Women

"Moderate-intensity exercise reduces the incidence of colds among postmenopausal women," Chubak J, McTiernan A, et al, Am J Med, 2006; 119(11): 937-42. (Address: Fred Hutchinson Cancer Research Center, Cancer Prevention Program, Seattle, Wash 98109-1024, USA).

In a randomized controlled trial involving 115 overweight and obese, sedentary postmenopausal women, exercising at a moderate-intensity for 45 minutes a day, five days a week for a period of one year was found to reduce the risk of colds, as compared to subjects who only participated in 45-minute stretching sessions once/week. Subjects were randomly divided into either the moderate-intensity exercise group, or the control group (once/week stretching), for a period of one year. During the last 3 months of the one year period, subjects in the control group experienced a three times greater risk of colds, as compared to subjects in the group exercising regularly. No significant differences in other upper respiratory tract infections were found, however, this may have been influenced by the difference in number of subjects who had received the flu vaccine in both groups. The results of this study suggest that postmenopausal women may reduce their likelihood of catching colds by exercising regularly (five days/week) at a moderate intensity. The authors conclude, "These findings are of public health relevance and add a new facet to the growing literature on the health benefits of moderate exercise."


Topic: Beneficial Effects of Eating Almonds

"Almonds Decrease Postprandial Glycemia, Insulinemia, and Oxidative Damage in Healthy Individuals," Jenkins DJA, Kendall CWC, et al, J Nutr., 2006; 136: 2987-2992. (Address: Clinical Nutrition and Risk Factor Modification Center and 3Department of Medicine, Division of Endocrinology and Metabolism, St. Michael's Hospital, Toronto, Ontario M5C 2T2, Canada).

In a study involving 15 healthy subjects, results indicate that consumption of almonds may decrease postprandial glycemia, insulinemia, and oxidative damage. The study assessed the effect of decreasing postprandial glucose excursions (may lower CHD risk) on measures of oxidative damage to lipids and proteins. The subjects received 5 meals, balanced in carbohydrate, fat, and protein, using butter and cheese: 2 bread meals (control), 1 bread + almonds meal, 1 parboiled rice meal, and 1 instant mashed potatoes meal. Blood samples were drawn at baseline and 4 hours postprandial. Glycemic indices and postprandial areas under the insulin concentration time curve were less than that for the potato meal. No differences in postprandial total antioxidant capacity were found. However, postprandial serum protein thiol concentrations increased with the almond meal - indicating less oxidative protein damage - and decreased with the control, rice, and potato meals (pooled data). Addi tionally, a negative association was observed between the change in protein thiols with postprandial incremental peak glucose and peak insulin responses. Thus, the authors of this study conclude, "… lowering postprandial glucose excursions may decrease the risk of oxidative damage to proteins. Almonds are likely to lower this risk by decreasing the glycemic excursion and by providing antioxidants. These actions may relate to mechanisms by which nuts are associated with a decreased risk of CHD."


Topic: Moderate Alcohol Intake May Lower Risk of Ischemic Heart Disease in Men with the Metabolic Syndrome

"Moderate Alcohol Consumption Is More Cardioprotective in Men with the Metabolic Syndrome," Gigleux I, Lamarche B, et al, J. Nutr., 2006; 136: 3027-3032. (Address: Institute on Nutraceuticals and Functional Foods, Quebec City, QC, Canada. E-Mail: benoit.lamarche@inaf.ulaval.ca ).

In a prospective cohort study involving 1,966 men from the Quebec Cardiovascular Study who were initially free of ischemic heart disease (IHD), moderate alcohol consumption was found to exert cardioprotective effects, especially among men with the metabolic syndrome. During 13 years of follow-up, 219 incident cases of IHD were identified. Men who consumed at least 15.2 g of alcohol per day - one drink is usually considered to be 12 ounces of beer, 5 ounces of wine, or 1½ ounces of spirits (hard liquor such as gin or whiskey), where each delivers about 12 to 14 grams of alcohol - were younger, and had higher plasma HDL cholesterol levels and lower plasma insulin, C-reactive protein and fibrinogen levels, than men who consumed less than 1.3 g of alcohol per day. Additionally, after adjusting for potential confounders, including coronary risk factors, consumption of at least 15.2 g of alcohol per day was associated with a 39% reduced risk of IHD, compared to alcohol consumpti on less than 1.3 g per day. In the subgroup of men with the metabolic syndrome, consumption of less than 15.2 g of alcohol per day was associated with a significantly increased risk of IHD (relative risk= 2.24). However, among men without the metabolic syndrome, consumption of less than 15.2 g of alcohol per day was not associated with a significant increased risk of IHD (relative risk= 1.31). Thus, the authors of this study conclude, "These results confirm that moderate daily alcohol consumption has cardioprotective properties and suggest that the effects may be more important in subjects with a deteriorated risk profile, such as those with the metabolic syndrome."


Topic: Chitosan Dietary Supplement May Facilitate Loss of Excess Body Fat
Keywords: OVERWEIGHT, OBESITY, WEIGHT LOSS, FAT LOSS - Chitosan Dietary Supplement

"Evaluating efficacy of a chitosan product using a double-blinded, placebo-controlled protocol," Kaats GR, Michalek JE, et al, J Am Coll Nutr, 2006; 25(5): 389-94. (Address: Health and Medical Research Center, 4940 Broadway, Suite 201, San Antonio, TX 78209, USA. E-mail: gil@hmrcenter.net ).

In a randomized, double-blind, placebo-controlled dietary intervention study involving overweight subjects, supplementation with chitosan (3,000 mg/d) was found to facilitate greater weight loss, fat loss, percentage of fat, and body mass composition improvement, compared with a placebo group. Of the 150 subjects who enrolled in the study, 134 completed the study and 111 were women who were similarly distributed in the three groups. Subjects were randomly divided into 3 groups. The active group received 6 capsules/day chitosan (each capsule containing 500 mg), and wore a pedometer during waking hours to record total daily steps taken. The placebo group received a placebo and wore a pedometer just like the active group. The control group followed any weight loss program of their own choosing. Results found that subjects in the treatment group experienced greater weight loss (-2.8 lbs vs. +0.8 lbs in the control group and +0.6 lbs in the placebo group), fat mass loss (-2. 6 lbs vs. +0.1 lbs in the control group and +0.6 lbs in the placebo group), and percentage of fat loss (-0.8% vs. +0.4% in the placebo group). Furthermore, compared with the placebo group, subjects in the treatment group were found to have a greater body composition improvement index (+2.4 lbs vs. -1.9 lbs). The results of this study suggest that supplementation with chitosan may be effective in helping overweight persons lose excess body fat and improve body composition under free-living conditions.

Source: Vitagram.com



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