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Biomedical subjects

Jennie Brand-Miller

Publications and source records attributed to Jennie Brand-Miller.

10 recordsLinked to original sources

The optimal diet for women with polycystic ovary syndrome?

An optimal diet is one that not only prevents nutrient deficiencies by providing sufficient nutrients and energy for human growth and reproduction, but that also promotes health and longevity and reduces the risk of diet-related chronic diseases. The composition of the optimal diet for women with polycystic ovary syndrome (PCOS) is not yet known, but such a diet must not only assist short term with weight management, symptoms and fertility, but also specifically target the long-term risks of type 2 diabetes, CVD and certain cancers. With insulin resistance and compensatory hyperinsulinaemia now recognised as a key factor in the pathogenesis of PCOS, it has become clear that reducing insulin levels and improving insulin sensitivity are an essential part of management. Diet plays a significant role in the regulation of blood glucose and insulin levels, yet research into the dietary management of PCOS is lacking and most studies have focused on energy restriction rather than dietary composition per se. On the balance of evidence to date, a diet low in saturated fat and high in fibre from predominantly low-glycaemic-index-carbohydrate foods is recommended. Because PCOS carries significant metabolic risks, more research is clearly needed.

Cardiovascular Diseases↗

Glycemic index, postprandial glycemia and cardiovascular disease.

PURPOSE OF REVIEW: Several lines of evidence indicate that exaggerated postprandial glycemia puts individuals without diabetes at greater risk of developing cardiovascular disease. In large, prospective observational studies, including meta-analyses, higher 120 min post-load blood glucose and glycated hemoglobin (a measure of average blood glucose level over time) independently predict cardiovascular mortality and morbidity in individuals without diabetes. These findings imply that the glycemic nature of dietary carbohydrates may also be relevant. We aim to provide a clearer perspective on how the glycemic impact of carbohydrates may modulate development of cardiovascular disease. RECENT FINDINGS: In ecological studies, average dietary glycemic index (a measure of the postprandial glycemic potential of carbohydrates) and glycemic load (average glycemic index x amount of carbohydrate) predicts coronary infarct and cardiovascular disease risk factors, including HDL cholesterol, triglycerides and C-reactive protein. In short-term intervention studies of overweight and hyperlipidemic patients, low glycemic index diets lead to improvements in cardiovascular disease risk factors, including reduced LDL cholesterol and improved insulin sensitivity, as well as greater body fat loss on energy-restricted diets. Molecular studies indicate that physiological hyperglycemia induces overproduction of superoxide by the mitochondrial electron-transport chain, resulting in inflammatory responses and endothelial dysfunction. SUMMARY: Taken together, the findings suggest that conventional high-carbohydrate diets with their high glycemic index may be suboptimal, particularly in insulin-resistant individuals. Because around one in four adults has impairments in postprandial glucose regulation, the glycemic potential of carbohydrates warrants further investigation in cardiovascular disease prevention.

Animals↗

Plagiarism.

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Humans↗

Brain ganglioside and glycoprotein sialic acid in breastfed compared with formula-fed infants.

BACKGROUND: The concentration of sialic acid in brain gangliosides and glycoproteins has been linked to learning ability in animal studies. Human milk is a rich source of sialic acid-containing oligosaccharides and is a potential source of exogenous sialic acid. OBJECTIVE: The aim of the study was to compare the sialic acid concentration in the brain frontal cortex of breastfed and formula-fed infants. DESIGN: Twenty-five samples of frontal cortex derived from infants who died of sudden infant death syndrome were analyzed. Twelve infants were breastfed, 10 infants were formula-fed, and 1 infant was mixed-fed; the feeding status of the remaining 2 infants was unknown. Ganglioside-bound and protein-bound sialic acid were determined by HPLC. Ganglioside ceramide fatty acids were also analyzed to determine the relation between sialic acid and long-chain polyunsaturated fatty acids. RESULTS: After adjustment for sex with age at death as a covariate, ganglioside-bound and protein-bound sialic acid concentrations were 32% and 22% higher, respectively, in the frontal cortex gray matter of breastfed infants than in that of formula-fed infants (P < 0.01). Protein-bound sialic acid increased with age in both groups (P = 0.02). In breastfed but not in formula-fed infants, ganglioside-bound sialic acid correlated significantly with ganglioside ceramide docosahexaenoic acid and total n-3 fatty acids. CONCLUSIONS: Higher brain ganglioside and glycoprotein sialic acid concentrations in infants fed human milk suggests increased synaptogenesis and differences in neurodevelopment.

Aging↗

Cocoa powder increases postprandial insulinemia in lean young adults.

We hypothesized that chocolate products elicit higher insulin responses than matched products with alternate flavoring. To test this, we used a within-subject, repeated-measures comparison of six pairs of foods, one flavored with chocolate (cocoa powder) and the other not. Healthy subjects (n = 10, 4 men, 6 women) tested each pair of foods. Postprandial glucose and insulin levels were determined at intervals over 2 h using standardized glycemic index (GI) methodology. The product categories were chocolate bars, cakes, breakfast cereals, ice creams, flavored milks and puddings. Although the GI did not differ within each pair, the insulin index (II) of the chocolate product was always higher, by a mean of 28%, than the alternate flavored product (P < 0.001). The greatest difference occurred within the flavored milk category in which the chocolate version elicited 45% greater insulinemia than the strawberry flavored milk (P = 0.021). Macronutrient composition (fat, protein, sugar, fiber or energy density) accounted for nearly all of the variation in GI among the foods, but did not explain differences in insulinemia. The presence of cocoa powder in foods leads to greater postprandial insulin secretion than alternate flavorings. Specific insulinogenic amino acids or greater cephalic phase insulin release may explain the findings.

Adult↗

Low-glycemic index diets in the management of diabetes: a meta-analysis of randomized controlled trials.

OBJECTIVE: The use of diets with low glycemic index (GI) in the management of diabetes is controversial, with contrasting recommendations around the world. We performed a meta-analysis of randomized controlled trials to determine whether low-GI diets, compared with conventional or high-GI diets, improved overall glycemic control in individuals with diabetes, as assessed by reduced HbA(1c) or fructosamine levels. RESEARCH DESIGN AND METHODS: Literature searches identified 14 studies, comprising 356 subjects, that met strict inclusion criteria. All were randomized crossover or parallel experimental design of 12 days' to 12 months' duration (mean 10 weeks) with modification of at least two meals per day. Only 10 studies documented differences in postprandial glycemia on the two types of diet. RESULTS: Low-GI diets reduced HbA(1c) by 0.43% points (CI 0.72-0.13) over and above that produced by high-GI diets. Taking both HbA(1c) and fructosamine data together and adjusting for baseline differences, glycated proteins were reduced 7.4% (8.8-6.0) more on the low-GI diet than on the high-GI diet. This result was stable and changed little if the data were unadjusted for baseline levels or excluded studies of short duration. Systematically taking out each study from the meta-analysis did not change the CIs. CONCLUSIONS: Choosing low-GI foods in place of conventional or high-GI foods has a small but clinically useful effect on medium-term glycemic control in patients with diabetes. The incremental benefit is similar to that offered by pharmacological agents that also target postprandial hyperglycemia.

Diabetes Mellitus, Type 1↗

Acne vulgaris: a disease of Western civilization.

BACKGROUND: In westernized societies, acne vulgaris is a nearly universal skin disease afflicting 79% to 95% of the adolescent population. In men and women older than 25 years, 40% to 54% have some degree of facial acne, and clinical facial acne persists into middle age in 12% of women and 3% of men. Epidemiological evidence suggests that acne incidence rates are considerably lower in nonwesternized societies. Herein we report the prevalence of acne in 2 nonwesternized populations: the Kitavan Islanders of Papua New Guinea and the Aché hunter-gatherers of Paraguay. Additionally, we analyze how elements in nonwesternized environments may influence the development of acne. OBSERVATIONS: Of 1200 Kitavan subjects examined (including 300 aged 15-25 years), no case of acne (grade 1 with multiple comedones or grades 2-4) was observed. Of 115 Aché subjects examined (including 15 aged 15-25 years) over 843 days, no case of active acne (grades 1-4) was observed. CONCLUSIONS: The astonishing difference in acne incidence rates between nonwesternized and fully modernized societies cannot be solely attributed to genetic differences among populations but likely results from differing environmental factors. Identification of these factors may be useful in the treatment of acne in Western populations.

Acne Vulgaris↗

Dietary approaches to overweight and obesity.

For years dietary guidelines for the treatment of overweight and obesity have advised a low-fat, high carbohydrate diet. Recent meta-analyses have shown that weight loss achieved with ad libitum low-fat diets is typically in the range of 3-4 kg. Although clinically significant, this weight loss is modest, usually regained on cessation of the intervention and the low-fat messages have not impacted on the ever increasing rates of overweight and obesity. Alternative approaches include low-glycemic index and high protein diets. Both effectively reduce the glycemic load of the diet and early studies suggest they may be effective in increasing satiety, reducing ad libitum energy intake and may improve fat oxidation by reducing insulin demand. Both approaches can be used within the context of a reduced-fat diet, with evidence emerging to suggest this may improve weight and body composition outcomes.

Caloric Restriction↗