Dietary glycaemic index and glycaemic load among Australian children and adolescents: results from the 2011-2012 Australian Health Survey.

This study aimed to examine the dietary glycaemic index (GI) and glycaemic load (GL) of Australian children and adolescents, as well as the major food groups contributing to GL, in the recent 2011-2012 Australian Health Survey. Plausible food intake data from 1876 children and adolescents (51 % boys), collected using a multiple-pass 24-h recall, were analysed. The GI of foods was assigned based on a step-wise published method using values from common GI databases. Descriptive statistics were calculated for dietary GI, GL and contribution to GL by food groups, stratified by age group and sex. Linear regression was used to test for trends across age groups for BMI, dietary GI and GL, and intakes of energy, nutrients and food groups. Pearson's χ 2 test was used to test for differences between age groups for categorical subject characteristic variables. Mean dietary GI and GL of participants were 55·5 (sd 5·3) and 137·4 (sd 50·8), respectively. The main contributors to dietary GL were starchy foods: breads, cereal-based dishes, breakfast cereals, flours, grains and potatoes accounted for 41 % of total GL. Sweetened beverages, fruit and vegetable juices/drinks, cake-type desserts and sweet biscuits contributed 15 %. No significant difference (at P<0·001) was observed between sexes. In conclusion, Australian children and adolescents appear to consume diets with a lower GI than European children. Exchanging high-GI foods for low-GI alternatives within core and non-core foods may improve diet quality of Australian children and adolescents.

Carbohydrate quality is not associated with liver enzyme activity and plasma TAG and HDL concentrations over 5 years in an older population.

Non-alcoholic fatty liver disease (NAFLD) is closely associated with insulin resistance and obesity. Hence, carbohydrate quality could be of relevance to the risk of NAFLD, but prospective data are lacking. The aim of the present study was to investigate longitudinal associations between carbohydrate quality (including dietary glycaemic index (GI) and intakes of sugar, starch and fibre) and markers of liver function in an older Australian population. The analysis was based on 866 participants ( ≥ 49 years) of the Blue Mountains Eye Study with fasting blood specimens and dietary intake data at baseline and 5-year follow-up. Multi-level mixed regression analysis was used to relate dietary GI and sugar, starch and fibre intake to the liver enzymes alanine aminotransferase (ALT) and γ-glutamyltransferase (GGT), as well as fasting TAG and HDL-cholesterol (HDL-C). After adjustment for potential confounding factors, a lower fibre intake was cross-sectionally related to higher GGT (P= 0.02) and fasting TAG (P= 0.002) levels, with fruit fibre being the most relevant fibre source (P= 0.095 for GGT; P= 0.003 for TAG). A higher dietary GI was associated with lower HDL-C (P= 0.046). Changes in carbohydrate quality during 5 years were not related to changes in ALT, GGT, TAG or HDL-C (P≥ 0.08). In conclusion, the absence of longitudinal associations between carbohydrate quality and liver enzymes and serum lipids in this older population does not support a major role of carbohydrate nutrition in liver function among the elderly.

Trends in added sugar supply and consumption in Australia: there is an Australian Paradox.

In 2011, Barclay and Brand-Miller reported the observation that trends in refined sugar consumption in Australia were the inverse of trends in overweight and obesity (The Australian Paradox). Rikkers et al. claim that the Australian Paradox is based on incomplete data because the sources utilised did not incorporate estimates for imported processed foods. This assertion is incorrect. Indeed, national nutrition surveys, sugar consumption data from the United Nations Food and Agricultural Organisation, the Australian Bureau of Statistics and Australian beverage industry data all incorporated data on imported products.

Methodology for the Review and Update of Nutrient Criteria Underpinning Front-of-Pack Labeling: Application to the Glycemic Index Symbol.

Background: Nutrient criteria underlying front-of-pack food labeling programs can play an important role in improving dietary intakes. Currently, no methodology for the development or update of nutrient criteria has been published, nor the methods used by food regulatory bodies. The scientific publication of methodology outlining the development and update of nutrient criteria underpinning front-of-pack food labeling programs highlighting healthier food choices is needed. Objective: To develop and provide a globally applicable and transparent methodology for researchers to follow when reviewing existing or developing new nutrient criteria for front-of-pack labeling. Methods: The Nutrient Criteria Methodology involved five phases: Phase I, the development of guiding principles; Phase II, collection of information for subsequent phases, including a pre-scope of the literature and selection of food composition database(s) for modeling; Phase III, literature review of all possible nutrients relevant to the nutrient criteria; Phase IV, database modeling to set quantitative limits for each selected nutrient; Phase V, assessment of the criteria against an established nutritional quality assessment tool. As an example, the methodology was applied to the update of the GI Symbol Product Eligibility and Nutrient Criteria (PENC). Results: A comprehensive and replicable methodology, based on best practice protocols and ensuring both scientific credibility and practicality of use by industry, was developed. Application of the five phases of the methodology to the GI Symbol PENC highlighted the ability of the methodology to uncover nutritional measures currently missing in many nutrient criteria for front-of-pack food labeling programs and other national food labeling systems, such as glycemic load and the unsaturated to saturated fat ratio. Foods achieving the PENC had a higher Health Star Rating than foods not achieving the PENC. Conclusion: Our Nutrient Criteria Methodology can be applied to the development and update of global nutrient criteria underpinning front-of-pack food labeling programs. Further research into the implementation of additional nutritional measures found to be important for human health is recommended, with the goal of the prevention of diet-related disease.

Dietary Glycaemic Index Labelling: A Global Perspective.

The glycaemic index (GI) is a food metric that ranks the acute impact of available (digestible) carbohydrates on blood glucose. At present, few countries regulate the inclusion of GI on food labels even though the information may assist consumers to manage blood glucose levels. Australia and New Zealand regulate GI claims as nutrition content claims and also recognize the GI Foundation's certified Low GI trademark as an endorsement. The GI Foundation of South Africa endorses foods with low, medium and high GI symbols. In Asia, Singapore's Healthier Choice Symbol has specific provisions for low GI claims. Low GI claims are also permitted on food labels in India. In China, there are no national regulations specific to GI; however, voluntary claims are permitted. In the USA, GI claims are not specifically regulated but are permitted, as they are deemed to fall under general food-labelling provisions. In Canada and the European Union, GI claims are not legal under current food law. Inconsistences in food regulation around the world undermine consumer and health professional confidence and call for harmonization. Global provisions for GI claims/endorsements in food standard codes would be in the best interests of people with diabetes and those at risk.

Dietary Fibre Consensus from the International Carbohydrate Quality Consortium (ICQC).

Dietary fibre is a generic term describing non-absorbed plant carbohydrates and small amounts of associated non-carbohydrate components. The main contributors of fibre to the diet are the cell walls of plant tissues, which are supramolecular polymer networks containing variable proportions of cellulose, hemicelluloses, pectic substances, and non-carbohydrate components, such as lignin. Other contributors of fibre are the intracellular storage oligosaccharides, such as fructans. A distinction needs to be made between intrinsic sources of dietary fibre and purified forms of fibre, given that the three-dimensional matrix of the plant cell wall confers benefits beyond fibre isolates. Movement through the digestive tract modifies the cell wall structure and may affect the interactions with the colonic microbes (e.g., small intestinally non-absorbed carbohydrates are broken down by bacteria to short-chain fatty acids, absorbed by colonocytes). These aspects, combined with the fibre associated components (e.g., micronutrients, polyphenols, phytosterols, and phytoestrogens), may contribute to the health outcomes seen with the consumption of dietary fibre. Therefore, where possible, processing should minimise the degradation of the plant cell wall structures to preserve some of its benefits. Food labelling should include dietary fibre values and distinguish between intrinsic and added fibre. Labelling may also help achieve the recommended intake of 14 g/1000 kcal/day.

Dietary Glycemic Index and Load and the Risk of Type 2 Diabetes: Assessment of Causal Relations.

While dietary factors are important modifiable risk factors for type 2 diabetes (T2D), the causal role of carbohydrate quality in nutrition remains controversial. Dietary glycemic index (GI) and glycemic load (GL) have been examined in relation to the risk of T2D in multiple prospective cohort studies. Previous meta-analyses indicate significant relations but consideration of causality has been minimal. Here, the results of our recent meta-analyses of prospective cohort studies of 4 to 26-y follow-up are interpreted in the context of the nine Bradford-Hill criteria for causality, that is: (1) Strength of Association, (2) Consistency, (3) Specificity, (4) Temporality, (5) Biological Gradient, (6) Plausibility, (7) Experimental evidence, (8) Analogy, and (9) Coherence. These criteria necessitated referral to a body of literature wider than prospective cohort studies alone, especially in criteria 6 to 9. In this analysis, all nine of the Hill's criteria were met for GI and GL indicating that we can be confident of a role for GI and GL as causal factors contributing to incident T2D. In addition, neither dietary fiber nor cereal fiber nor wholegrain were found to be reliable or effective surrogate measures of GI or GL. Finally, our cost-benefit analysis suggests food and nutrition advice favors lower GI or GL and would produce significant potential cost savings in national healthcare budgets. The high confidence in causal associations for incident T2D is sufficient to consider inclusion of GI and GL in food and nutrient-based recommendations.

Dietary Glycemic Index and Load and the Risk of Type 2 Diabetes: A Systematic Review and Updated Meta-Analyses of Prospective Cohort Studies.

Published meta-analyses indicate significant but inconsistent incident type-2 diabetes(T2D)-dietary glycemic index (GI) and glycemic load (GL) risk ratios or risk relations (RR). It is nowover a decade ago that a published meta-analysis used a predefined standard to identify validstudies. Considering valid studies only, and using random effects dose-response meta-analysis(DRM) while withdrawing spurious results (p < 0.05), we ascertained whether these relationswould support nutrition guidance, specifically for an RR > 1.20 with a lower 95% confidence limit>1.10 across typical intakes (approximately 10th to 90th percentiles of population intakes). Thecombined T2D-GI RR was 1.27 (1.15-1.40) (p < 0.001, n = 10 studies) per 10 units GI, while that forthe T2D-GL RR was 1.26 (1.15-1.37) (p < 0.001, n = 15) per 80 g/d GL in a 2000 kcal (8400 kJ) diet.The corresponding global DRM using restricted cubic splines were 1.87 (1.56-2.25) (p < 0.001, n =10) and 1.89 (1.66-2.16) (p < 0.001, n = 15) from 47.6 to 76.1 units GI and 73 to 257 g/d GL in a 2000kcal diet, respectively. In conclusion, among adults initially in good health, diets higher in GI or GLwere robustly associated with incident T2D. Together with mechanistic and other data, thissupports that consideration should be given to these dietary risk factors in nutrition advice.Concerning the public health relevance at the global level, our evidence indicates that GI and GLare substantial food markers predicting the development of T2D worldwide, for persons ofEuropean ancestry and of East Asian ancestry.

Declining consumption of added sugars and sugar-sweetened beverages in Australia: a challenge for obesity prevention.

Background: Reduced intakes of added sugars and sugar-sweetened beverages (SSBs) have been the main focus of efforts to stall obesity. Although obesity has risen steeply in Australia, some evidence suggests that added-sugars and SSB intakes have declined over the same time frame.Objective: We investigated recent trends in the availability of sugars and sweeteners and changes in intakes of total sugars, added sugars, and SSBs in Australia by using multiple, independent data sources.Design: The study was designed to compare relevant data published by the Food and Agriculture Organization of the United Nations [FAO Statistics Division Database (FAOSTAT)], the Australian government, academia, and the food industry.Results: With the use of the FAOSTAT food balance sheets for Australia, the per capita availability of added or refined sugars and sweeteners was shown to have fallen 16% from 152 g/d in 1980 to 127 g/d in 2011 (P-trend = 0.001). In national dietary surveys in 1995 and 2011-2012, added-sugars intake declined markedly in adult men (from 72 to 59 g/d; -18%) but not in women (44-42 g/d; NS). As a proportion of total energy, added-sugars intake fell 10% in adult men but nonsignificantly in adult women. Between 1995 and 2011-2012, the proportion of energy from SSBs (including 100% juice) declined 10% in adult men and 20% in women. More marked changes were observed in children aged 2-18 y. Data from national grocery sales indicated that per capita added-sugars intakes derived from carbonated soft drinks fell 26% between 1997 and 2011 (from 23 to 17 g/d) with similar trends for noncarbonated beverages.Conclusions: In Australia, 4 independent data sets confirmed shorter- and longer-term declines in the availability and intake of added sugars, including those contributed by SSBs. The findings challenge the widespread belief that energy from added sugars or sugars in solution are uniquely linked to the prevalence of obesity.

Dietary glycaemic index and glycaemic load among Australian adults - results from the 2011-2012 Australian Health Survey.

This study aimed to determine the major food groups contributing to dietary glycaemic load (GL). Plausible food intake data collected using a multiple-pass 24 hour recall from a weighted sample of 6326 adult respondents (52% male) of the 2011-2012 Australian Health Survey dataset (AHS) were analysed. The GI of foods was estimated based on a previously published step-wise method. Descriptive statistics were calculated for dietary glycaemic index (GI), GL and contribution to GL by major food groups, stratified by age and sex. Trends across age groups were assessed using linear regression. Pearson's χ2 was used to test for differences between age groups for categorical demographics variables. The mean (SD) dietary GI and GL was 54 (7) and 135 (59) respectively and the top 3 contributors to dietary GL were breads (14.4%), cereal-based dishes (10.3%) and breakfast cereals (ready to eat) (6.6%). There were small but significant differences in the GL contribution pattern between the sexes. The findings indicate that the average dietary GI of Australian adults is similar to that of other population groups, with a large proportion of starchy and energy-dense nutrient-poor foods that contribute to a high GL.

Changes in dietary glycemic index and glycemic load in Australian adults from 1995 to 2012.

Background: Australians have used the glycemic index (GI) since 1995; however, there are no data on changes in carbohydrate quality over time.Objectives: The aim was to compare average dietary GI and glycemic load (GL), and contributing carbohydrate foods, in the 2 most recent national dietary surveys.Design: Dietary data from adult participants of national nutrition surveys conducted in 1995 (the 1995 Australian National Nutrition Survey; n = 8703) and 2012 (the 2011-2012 National Nutrition and Physical Activity Survey; n = 6278), collected by a single 24-h recall, were analyzed. The differences in mean dietary GI and GL between surveys were compared by using 1-factor ANOVA. The main sources of dietary GL in the 2 surveys were also assessed. Multiple linear regression was performed to examine the contributions of the food groups to interindividual variations in dietary GI and GL.Results: Overall, dietary GI and GL decreased by 5% and 12%, respectively, from 1995 to 2012 (GI on glucose standard: 56.5 ± 6.2 compared with 53.9 ± 6.8, respectively; GL: 153.3 ± 62.1 compared with 135.4 ± 58.5, respectively; both P < 0.001). Breads were the main contributor to GL at both time points. Potatoes and sweetened beverages contributed less, whereas cereal-based dishes contributed more in 2012 than in 1995. The top 20 GL-contributing food groups explained less interindividual variation in dietary GI (R2: 0.376 compared with 0.290) and GL (R2: 0.825 compared with 0.770) in 2012 than in 1995.Conclusion: Although the average dietary GI and GL declined between 1995 and 2012, trends in specific carbohydrate foods suggest that Australians are avoiding potatoes and sugary beverages in favor of a greater variety of carbohydrate foods, particularly cereal products.

Efficacy of carbohydrate counting in type 1 diabetes: a systematic review and meta-analysis.

BACKGROUND: Although carbohydrate counting is the recommended dietary strategy for achieving glycaemic control in people with type 1 diabetes, the advice is based on narrative review and grading of the available evidence. We aimed to assess by systematic review and meta-analysis the efficacy of carbohydrate counting on glycaemic control in adults and children with type 1 diabetes. METHODS: We screened and assessed randomised controlled trials of interventions longer than 3 months that compared carbohydrate counting with general or alternate dietary advice in adults and children with type 1 diabetes. Change in glycated haemoglobin (HbA1c) concentration was the primary outcome. The results of clinically and statistically homogenous studies were pooled and meta-analysed using the random-effects model to provide estimates of the efficacy of carbohydrate counting. FINDINGS: We identified seven eligible trials, of 311 potentially relevant studies, comprising 599 adults and 104 children with type 1 diabetes. Study quality score averaged 7·6 out of 13. Overall there was no significant improvement in HbA1c concentration with carbohydrate counting versus the control or usual care (-0·35% [-3·9 mmol/mol], 95% CI -0·75 to 0·06; p=0·096). We identified significant heterogeneity between studies, which was potentially related to differences in study design. In the five studies in adults with a parallel design, there was a 0·64% point (7·0 mmol/mol) reduction in HbA1c with carbohydrate counting versus control (95% CI -0·91 to -0·37; p<0·0001). INTERPRETATION: There is some evidence to support the recommendation of carbohydrate counting over alternate advice or usual care in adults with type 1 diabetes. Additional studies are needed to support promotion of carbohydrate counting over other methods of matching insulin dose to food intake. FUNDING: None.

The Australian paradox: a substantial decline in sugars intake over the same timeframe that overweight and obesity have increased.

Ecological research from the USA has demonstrated a positive relationship between sugars consumption and prevalence of obesity; however, the relationship in other nations is not well described. The aim of this study was to analyze the trends in obesity and sugar consumption in Australia over the past 30 years and to compare and contrast obesity trends and sugar consumption patterns in Australia with the UK and USA. Data on consumption of sugar in Australia, the UK and USA were obtained from the Food and Agriculture Organization for the years 1980-2003. The prevalence of obesity has increased 3 fold in Australians since 1980. In Australia, the UK and USA, per capita consumption of refined sucrose decreased by 23%, 10% and 20% respectively from 1980 to 2003. When all sources of nutritive sweeteners, including high fructose corn syrups, were considered, per capita consumption decreased in Australia (-16%) and the UK (-5%), but increased in the USA (+23%). In Australia, there was a reduction in sales of nutritively sweetened beverages by 64 million liters from 2002 to 2006 and a reduction in percentage of children consuming sugar-sweetened beverages between 1995 and 2007. The findings confirm an "Australian Paradox"--a substantial decline in refined sugars intake over the same timeframe that obesity has increased. The implication is that efforts to reduce sugar intake may reduce consumption but may not reduce the prevalence of obesity.

Informing food choices and health outcomes by use of the dietary glycemic index.

Considerable epidemiologic evidence links consuming lower glycemic index (GI) diets with good health, particularly upon aging. The GI is a kinetic parameter that reflects the ability of carbohydrate (CHO) contained in consumed foods to raise blood glucose in vivo. Newer nutritional, clinical, and experimental data link intake of lower dietary GI foods to favorable outcomes of chronic diseases, and compel further examination of the record. Based upon the new information there are two specific questions: 1) should the GI concept be promoted as a way to prolong health, and 2) should food labels contain GI information? Further, what are the remaining concerns about methodological issues and consistency of epidemiological data and clinical trials that need to be resolved in order to exploit the benefits of consuming lower GI diets? These issues are addressed in this review.

Carbohydrate nutrition and inflammatory disease mortality in older adults.

BACKGROUND: Several studies suggest that carbohydrate nutrition is related to oxidative stress and inflammatory markers. OBJECTIVE: We examined whether dietary glycemic index (GI), dietary fiber, and carbohydrate-containing food groups were associated with the mortality attributable to noncardiovascular, noncancer inflammatory disease in an older Australian cohort. DESIGN: Analysis included 1490 postmenopausal women and 1245 men aged ge 49 y at baseline (1992-1994) from a population-based cohort who completed a validated food-frequency questionnaire. Cox proportional hazards ratios were calculated both for death from diseases in which inflammation or oxidative stress was a predominant contributor and for cardiovascular mortality. RESULTS: Over a 13-y period, 84 women and 86 men died of inflammatory diseases. Women in the highest GI tertile had a 2.9-fold increased risk of inflammatory death compared with women in the lowest GI tertile [multivariate hazard ratio in energy-adjusted tertile 3 (tertile 1 as reference): 2.89; 95% CI: 1.52, 5.51; P for trend: 0.0006, adjusted for age, smoking, diabetes, and alcohol and fiber consumption]. Increasing intakes of foods high in refined sugars or refined starches (P = 0.04) and decreasing intakes of bread and cereals (P = 0.008) or vegetables other than potatoes (P = 0.007) also independently predicted a greater risk, with subjects' GI partly explaining these associations. In men, only an increased consumption of fruit fiber (P = 0.005) and fruit (P = 0.04) conferred an independent decrease in risk of inflammatory death. No associations were observed with cardiovascular mortality. CONCLUSION: These data provide new epidemiologic evidence of a potentially important link between GI and inflammatory disease mortality among older women.