J Am Diet Assoc
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Review Meta Analysis
The effect of grape seed extract on cardiovascular risk markers: a meta-analysis of randomized controlled trials.
Recent animal studies have suggested that grape seed extract has beneficial effects on the cardiovascular system. Randomized trials in human beings have yielded conflicting results. The objective of this systematic review was to assess the effect of grape seed extract on changes in blood pressure, heart rate, lipid levels, and C-reactive protein (CRP) levels. ⋯ Egger's weighted regression statistic suggested low likelihood of publication bias in all analysis (P>0.05 for all), except for the effect on diastolic blood pressure (P=0.046). Based on the currently available literature, grape seed extract appears to significantly lower systolic blood pressure and heart rate, with no effect on lipid or CRP levels. Larger randomized, double-blinded trials evaluating different dosages of grape seed extract and for longer follow-up durations are needed.
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Asthma is characterized by lung airway inflammation initiated and perpetuated by an inappropriate immune response, increased airway responsiveness, and variable airflow obstruction. In Western countries there has been a marked increase in asthma prevalence such that it has become a public health concern. It has been hypothesized that the increase may be due to changing antioxidant intake, increasing dietary ratio of n-6:n-3 polyunsaturated fatty acids (PUFA), and vitamin D deficiency (and supplementation). ⋯ Interest in the potential of dietary intervention during pregnancy to reduce the likelihood of childhood asthma has increased. A small number of cohort studies have highlighted associations between childhood asthma and reduced maternal intake of some nutrients (vitamin E, vitamin D, selenium, zinc, and PUFA) during pregnancy. Although vitamin D intervention studies during pregnancy are ongoing and two intervention studies suggest that dietary PUFA manipulation during pregnancy may be advantageous, further trials are needed to establish if modification of maternal nutrient intake during pregnancy can be used as a healthy, low cost, public health measure to reduce the prevalence of childhood asthma.
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Review
Trans fats in America: a review of their use, consumption, health implications, and regulation.
Trans fatty acids have long been used in food manufacturing due in part to their melting point at room temperature between saturated and unsaturated fats. However, increasing epidemiologic and biochemical evidence suggest that excessive trans fats in the diet are a significant risk factor for cardiovascular events. A 2% absolute increase in energy intake from trans fat has been associated with a 23% increase in cardiovascular risk. ⋯ This likelihood is exacerbated by the Food and Drug Administration labeling rules, which allow products containing <0.5 g trans fat per serving to claim 0 g trans fat. Many products with almost 0.5 g trans fat, if consumed over the course of a day, may approximate or exceed the 2 g maximum as recommended by American Heart Association, all while claiming to be trans-fat free. Accordingly, greater transparency in labeling and/or active consumer education is needed to reduce the cardiovascular risks associated with trans fats.
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The development and promotion of farmers' markets and community gardens is growing in popularity as a strategy to increase community-wide fruit and vegetable consumption. Despite large numbers of farmers' markets and community gardens in the United States, as well as widespread enthusiasm for their use as a health promotion tool, little is known about their influence on dietary intake. This review examines the current scientific literature on the implications of farmers' market programs and community gardens on nutrition-related outcomes in adults. ⋯ Seven studies focused on the impact of farmers' market nutrition programs for Special Supplemental Nutrition Program for Women, Infants, and Children participants, five focused on the influence of farmers' market programs for seniors, and four focused on community gardens. Findings from this review reveal that few well-designed research studies (eg, those incorporating control groups) utilizing valid and reliable dietary assessment methods to evaluate the influence of farmers' markets and community gardens on nutrition-related outcomes have been completed. Recommendations for future research on the dietary influences of farmers' markets and community gardens are provided.
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This review summarizes what is known about the effect of diet on irritable bowel syndrome (IBS) symptoms emphasizing data from randomized, controlled clinical trials. Studies suggest that IBS symptoms in one quarter of patients may be caused or exacerbated by one or more dietary components. Recent studies indicate that a diet restricted in fermentable, poorly absorbed carbohydrates, including fructose, fructans (present in wheat and onions), sorbitol, and other sugar alcohols is beneficial, but confirmatory studies are needed. ⋯ In clinical practice, it is very difficult to establish that a patient's symptoms result from an adverse reaction to food. A double blind placebo-controlled food challenge is the most reliable method, but it is not suitable for routine clinical use. A modified exclusion diet and stepwise reintroduction of foods or trials of eliminating classes of food may be useful.