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Background: Dietary intervention in cystic fibrosis (CF) has historically focused on high-energy diets to address malnutrition, with little attention on diet quality. With increased survival, CF complications such as impaired glucose tolerance (IGT) and cystic fibrosis related diabetes (CFRD) have increased in prevalence. In the absence of consensus on the management of IGT, the role of dietary intake, specifically carbohydrate quality, requires consideration., Aims: The aims of this study were to: 1) determine nutritional quality of dietary intake at an adult CF clinic and compare this to the Australian Dietary Guidelines 2) explore relationships between dietary intake, including glycaemic index (GI) and glycaemic load (GL), and glucose response variables using continuous glucose monitoring (CGM)., Methods: Adults attending a Sydney hospital were recruited to undergo CGM for five-seven days and record dietary intake using a food record over the CGM period. The relationship between variables of dietary intake, including GI and GL and variables of glycaemic response, including mean amplitude of glycaemic excursions (MAGE), percentage of time in hyperglycaemic and euglycaemic range, were determined., Results: Eighteen participants completed the study with 87 full days of dietary and CGM data. Dietary intake was higher than recommendations in the Australian Dietary Guidelines in relation to grains and protein foods and only slightly higher in saturated fat. Bivariate correlations showed dietary GI was significantly positively associated with percentage of time in hyperglycaemic range. Dietary GL was significantly associated with SD, MAGE and percentage of time in euglycaemic range on CGM. Results remained significant when controlled for energy intake in partial correlation analyses., Conclusions: This study suggests GI and GL may be important dietary factors influencing glucose metabolism in CF. Further studies exploring low GI or GL diets as a dietary intervention in CF are the next step., Competing Interests: Conflict of Interest JBM is President of not-for-profit Glycaemic Index Foundation, director of a GI testing service and author of books about the GI., (Copyright © 2019 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)

Higher-protein diets have been advocated for body-weight regulation for the past few decades. However, the potential health risks of these diets are still uncertain. We aimed to develop a protein score based on the quantity and source of protein, and to examine the association of the score with glycated haemoglobin (HbA1c) and estimated glomerular filtration rate (eGFR). Analyses were based on three population studies included in the PREVIEW project (PREVention of diabetes through lifestyle Intervention and population studies in Europe and around the World): NQplus, Lifelines, and the Young Finns Study. Cross-sectional data from food-frequency questionnaires ( n = 76,777 subjects) were used to develop a protein score consisting of two components: 1) percentage of energy from total protein, and 2) plant to animal protein ratio. An inverse association between protein score and HbA1c (slope -0.02 ± 0.01 mmol/mol, p < 0.001) was seen in Lifelines. We found a positive association between the protein score and eGFR in Lifelines (slope 0.17 ± 0.02 mL/min/1.73 m², p < 0.0001). Protein scoring might be a useful tool to assess both the effect of quantity and source of protein on health parameters. Further studies are needed to validate this newly developed protein score., Competing Interests: J.B.M. is president of the Glycemic Index Foundation, a non-profit food endorsement programme, manager of a GI testing service at the University of Sydney and the co-author of books about the GI foods. S.D.P holds the Fonterra Chair in Human Nutrition at the University of Auckland. None of the other authors declare a conflict of interest.

&#160;The aim of this study was to examine the monetary cost of dietary change among pregnant women before and after receiving low glycaemic index (GI) dietary advice. The pregnant women in this study were a subgroup of participants in the Pregnancy and Glycaemic Index Outcomes (PREGGIO) study. Twenty women from the low GI dietary advice group, who had completed their pregnancies, were randomly chosen. All these women had completed three day food records at 12&#8211;16 weeks and again around 36 weeks of gestation. Consumer food prices were applied to recorded dietary intake data. The mean &#177; SD GI of the diet reduced from 55.1 &#177; 4.3 to 51.6 &#177; 3.9 (p = 0.003). The daily cost of the diet (AUD) was 9.1 &#177; 2.7 at enrolment and 9.5 &#177; 2.1 prior to delivery was not significantly different (p = 0.52). There were also no significant differences in the daily energy intake (p = 0.2) or the daily cost per MJ (p = 0.16). Women were able to follow low GI dietary advice during pregnancy with no significant increase in the daily costs.

Purpose of Review: In recent years, many of the concerns surrounding the glycemic index have been addressed by methodological studies and clinical trials comparing diets carefully matched for other nutrients. These findings are reviewed together with new observational evidence for the role of the dietary glycemic index in the etiology of cardiovascular disease., Recent Findings: The determination and classification of the glycemic index of a food product is now standardized by the International Standards Organization. Systematic studies using isoenergetic single and mixed meals have shown that glycemic index and/or glycemic load are stronger predictors of postprandial glycemia and insulinemia than carbohydrate content alone. In overweight individuals, a diet that combined modestly higher protein and lower glycemic index carbohydrates was the most effective diet for prevention of weight regain. New observational studies have reported increased risks of coronary heart disease associated with higher intakes of carbohydrates from high glycemic index foods. Epidemiological evidence has emerged linking dietary glycemic index to visceral fat and inflammatory disease mortality., Summary: There is growing recognition that replacing saturated fat with refined, high glycemic index carbohydrates increases postprandial glycemia and may be detrimental for weight control and predisposition to cardiovascular and inflammatory disease. In contrast, low glycemic index carbohydrates reduce risk.

Objective: Insulin may play a role in prostate cancer tumorigenesis. Postprandial blood glucose and insulin responses of foods depend importantly on the carbohydrate quality and quantity, represented by glycemic index (GI), glycemic load (GL), fiber and whole-grain content, but are also influenced by intake of protein and other characteristics. The recently developed insulin index (II) quantifies the postprandial insulin secretion, also taking into account these additional characteristics., Methods: We investigated the association between dietary GI, GL, II, fiber, and whole grains and risk of total prostate cancer (n = 5,112) and subgroups of prostate cancer as defined by stage or grade in 49,934 male participants of the Health Professionals Follow-up Study. Multivariate adjusted hazard ratios (HR) and 95% confidence intervals (95% CI) were estimated using Cox proportional hazards regression., Results: Dietary GI, GL, II, or fiber was not associated with risk of total or subgroups of prostate cancer. We observed a positive association between dietary intake of whole grains and total prostate cancer (HR highest versus lowest quintile 1.13, 95% CI 1.03-1.24), which was attenuated after restriction to PSA-screened participants (HR 1.03, 95% CI 0.91-1.17)., Conclusions: These results suggest that long-term exposure to a diet with a high insulin response does not affect prostate cancer incidence.

Age-related hearing loss is a frequent disability in older adults and nutrition could play a role in the development of this condition. Carbohydrate nutrition [including dietary glycemic index (GI) and load (GL)] may be linked to hearing loss. We aimed to determine the association between carbohydrate nutrition (including mean dietary GI and GL, and the dietary intakes of carbohydrate and sugar), starch, cereal and total fiber, and age-related hearing loss. The Blue Mountains Hearing Study is a population-based survey of age-related hearing loss (1997-1999 to 2002-2004). Hearing loss was measured in 2956 participants (aged ≥50 y) and was defined as the pure-tone average of frequencies 0.5, 1.0, 2.0, and 4.0 kHz > 25 dB hearing level. Dietary data were collected in a semiquantitative FFQ. A purpose-built database based on Australian GI values was used to calculate the mean GI. A higher mean dietary GI was associated with an increased prevalence of any hearing loss, comparing quintiles 1 (lowest) and 5 (highest), [multivariable-adjusted odds ratio = 1.41 (95% CI = 1.01-1.97)]. Participants in the highest quartile of mean dietary GL intake compared with those in the lowest quartile had a 76% greater risk of developing incident hearing loss (P-trend = 0.04). Higher carbohydrate and sugar intakes were associated with incident hearing loss (P-trend = 0.03 and P-trend = 0.05, respectively). In summary, a high-GL diet was a predictor of incident hearing loss, as was higher intake of total carbohydrate. Hence, high postprandial glycemia might be a potential underlying biological mechanism in the development of age-related hearing loss.

Intramyocellular lipid (IMCL) and plasma NEFA are important skeletal muscle fuel sources. By raising blood insulin concentrations, carbohydrate ingestion inhibits lypolysis and reduces circulating NEFA. We hypothesised that differences in the postprandial glycaemic and insulin response to carbohydrates (i.e. glycaemic index; GI) could alter NEFA availability and IMCL use during subsequent exercise. Endurance-trained individuals (n 7) cycled for 90 min at 70 % V O2peak and then consumed either high GI (HGI) or low GI (LGI) meals over the following 12 h. The following day after an overnight fast, the 90 min cycle was repeated. IMCL content of the vastus lateralis was quantified using magnetic resonance spectroscopy before and after exercise. Blood samples were collected at 15 min intervals throughout exercise and analysed for NEFA, glycerol, glucose, insulin, and lactate. Substrate oxidation was calculated from expired air samples. The 90 min cycle resulted in >2-fold greater reduction in IMCL in the HGI trial (3.5 (sem 1.0) mm/kg wet weight) than the LGI trial (1.6 (sem 0.3) mm/kg wet weight, P < 0.05). During exercise, NEFA availability was reduced in the HGI trial compared to the LGI trial (area under curve 2.36 (sem 0.14) mEq/l per h v. 3.14 (sem 0.28) mEq/l per h, P < 0.05 respectively). No other differences were significant. The findings suggest that HGI carbohydrates reduce NEFA availability during exercise and increase reliance on IMCL as a substrate source during moderate intensity exercise.

Background: Despite the popularity of low-glycemic index (GI) and high-protein diets, to our knowledge no randomized, controlled trials have systematically compared their relative effects on weight loss and cardiovascular risk., Methods: A total of 129 overweight or obese young adults (body mass index, > or =25 [calculated as weight in kilograms divided by the square of height in meters]) were assigned to 1 of 4 reduced-fat, high-fiber diets for 12 weeks. Diets 1 and 2 were high carbohydrate (55% of total energy intake), with high and low GIs, respectively; diets 3 and 4 were high protein (25% of total energy intake), with high and low GIs, respectively. The glycemic load was highest in diet 1 and lowest in diet 4. Changes in weight, body composition, and blood chemistry profile were studied., Results: While all groups lost a similar mean +/- SE percentage of weight (diet 1, -4.2% +/- 0.6%; diet 2, -5.5% +/- 0.5%; diet 3, -6.2% +/- 0.4%; and diet 4, -4.8% +/- 0.7%; P = .09), the proportion of subjects in each group who lost 5% or more of body weight varied significantly by diet (diet 1, 31%; diet 2, 56%; diet 3, 66%; and diet 4, 33%; P = .01). Women on diets 2 and 3 lost approximately 80% more fat mass (-4.5 +/- 0.5 [mean +/- SE] kg and -4.6 +/- 0.5 kg) than those on diet 1 (-2.5 +/- 0.5 kg; P = .007). Mean +/- SE low-density-lipoprotein cholesterol levels declined significantly in the diet 2 group (-6.6 +/- 3.9 mg/dL [-0.17 +/- 0.10 mmol/L]) but increased in the diet 3 group (+10.0 +/- 3.9 mg/dL [+0.26 +/- 0.10 mmol/L]; P = .02). Goals for energy distribution were not achieved exactly: both carbohydrate groups ate less fat, and the diet 2 group ate more fiber., Conclusion: Both high-protein and low-GI regimens increase body fat loss, but cardiovascular risk reduction is optimized by a high-carbohydrate, low-GI diet.

There is growing awareness that the profound changes in the environment (eg, in diet and other lifestyle conditions) that began with the introduction of agriculture and animal husbandry approximately 10000 y ago occurred too recently on an evolutionary time scale for the human genome to adjust. In conjunction with this discordance between our ancient, genetically determined biology and the nutritional, cultural, and activity patterns of contemporary Western populations, many of the so-called diseases of civilization have emerged. In particular, food staples and food-processing procedures introduced during the Neolithic and Industrial Periods have fundamentally altered 7 crucial nutritional characteristics of ancestral hominin diets: 1) glycemic load, 2) fatty acid composition, 3) macronutrient composition, 4) micronutrient density, 5) acid-base balance, 6) sodium-potassium ratio, and 7) fiber content. The evolutionary collision of our ancient genome with the nutritional qualities of recently introduced foods may underlie many of the chronic diseases of Western civilization.

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.

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.

Background -- Compared with conventional low fat diets, high-protein and low-glycemic index (GI) diets have been associated with greater rate of weight loss. While both methods reduce dietary glycemic load (GL), the effects on cardiovascular risk may differ. Objective -- To evaluate the effects of 4 diets varying in GL, GI and protein on lipid and glucose metabolism. Design -- A 12-week randomised trial of 4 ad libitum diets: diet 1 was a high carbohydrate, high GI diet (HGI), diet 2 was similarly high in carbohydrate but low GI (LGI), diets 3 and 4 replaced some of the carbohydrate with protein, specifically from lean red meat, and included carbohydrate from either high or low GI foods (HP/HGI and HP/LGI respectively). The diets were similar in fat (30% energy) and type of fat. All key foods and some pre-prepared meals were provided on a weekly basis to assist compliance. Fasting blood samples were taken 0, 6 and 13 weeks. Outcomes -- In total, 129 subjects were recruited and 116 completed the intervention. Changes in weight and body composition were reported previously. In the primary intention-to-treat analysis, total cholesterol and LDL-cholesterol changes showed significant differences among the 4 diets (P = 0.04 and 0.019 respectively). Despite similar weight loss, total and LDL-cholesterol rose by +5% and +8% respectively on the HP/HGI diet and fell by -4% and -6% respectively on the LGI diet (p = 0.033 and 0.013 for total and LDL-cholesterol respectively). Overall, there was a significant effect of GI, but not protein content, on change in total cholesterol (P = 0.019) and LDL cholesterol (P = 0.009). HDL-cholesterol rose and triglyceride concentrations fell in all groups with no differences among the four diets. Conclusions -- Reduced GL diets have varying effects on cardiovascular risk factors. Low GI carbohydrate foods may be more important in high protein diets because of their capacity to attenuate undesirable changes in lipid metabolism. [ABSTRACT FROM AUTHOR]

Background -- Recent evidence suggests that the inclusion of low glycaemic index (GI) foods in the diet may be protective against cardiovascular disease via either increased HDL-cholesterol concentrations, reduced inflammatory response in the endothelium, or both mechanisms. Objective -- To describe the nutritional characteristics of patients with existing cardiovascular disease who were consuming a low versus high GI diet. Design -- As part of baseline data collection for the LIPID trial, 1,077 participants also agreed to complete a semiquantified FFQ investigating intakes of more than 170 foods. All foods which contributed significantly to dietary carbohydrate intake were allocated a GI value where available. Total dietary GI was calculated by determining an individuals average daily glycaemic load and dividing by the average total carbohydrate consumed in grams per day. Patients were classified into 4 groups according to their quartile of dietary GI, and the relationship between nutrition variables and GI was investigated by regressions of individual patient nutrition variables on GI quartile medians. Outcomes -- There were significant positive relationships between dietary GI and dietary energy, fat and carbohydrate intakes, and significant negative relationships between dietary GI and protein and alcohol intakes. Dietary GI was also significantly positively related to mono- and poly-unsaturated fat intakes, but not to saturated fat intake. Conclusion -- These data indicate that those patients with existing cardiovascular disease who tended to eat a diet that was higher in GI were also consuming more energy, less alcohol, more dietary carbohydrate and more dietary fat (including more mono- and poly-unsaturated fats), at the expense of dietary protein intake. [ABSTRACT FROM AUTHOR]

Background - In the science of weight loss, the value of diets with a low glycemic index (GI) or glycemic load (GL) is controversial. GL remains an unproven concept without evidence that the calculated GL predicts blood glucose and insulin responses to mixed meals. Objective - To compare day-long glucose and insulin responses to four isoenergetic reduced fat diets, varying in GL, carbohydrate and protein content. Design - A randomised, four-intervention, crossover study was conducted in 11 overweight or obese females (age: 26.5 ± 4.4 yr, BMI: 30.0 ± 4.3 kg/m²). The four diets were: a conventional low-fat high-GI diet (55% CHO, 15% protein, 30% fat, GL 116); a low-GI diet (55% CHO, 15% protein, 30% fat, GL 65); a high protein-high GI diet (45% CHO, 25% protein, 30% fat, GL 84); and high protein-low GI diet (45% CHO, 25%-protein, 30% fat, GL 43). Subjects consumed 3 mixed meals and 1 snack at intervals over 10 h. Fingerprick capillary blood samples (n = 14) were collected at 30-60 min intervals and analysed for glucose and insulin. Outcomes - Incremental area under the curve (AUC, mean ± SE) was calculated (table). Using regression analysis, GL was significantly correlated with glucose AUC (r = 0.35, P = 0.022) and insulin AUC (r = 0.35, P = 0.021). Varying the GI had a stronger effect (P = 0.026) on glucose response than varying the carbohydrate (P = 0.046) but only carbohydrate amount had a significant effect on insulin response (P = 0.002). Conclusions - Dietary GL has a predictable effect on day-long glucose and insulin responses in overweight and obese females. Diets with lower GL may be helpful for weight control. [ABSTRACT FROM AUTHOR]

Presents abstracts of articles on the topic of dietary intakes in the field of clinical nutrition. 'Nutrients, food and cardiovascular health-distinguishing fact from fantasy'; 'Application of gene technology to improve nutritional value of plant-based foods'; 'Dairy foods and asthma: perception, association and evidence-based links'; 'Dairy bioactives: from paddock to functional food and dietary supplement.'