Validity of carbohydrate, glycaemic index and glycaemic load data obtained using a semi-quantitative food-frequency questionnaire

Development and validation of a comprehensive food frequency questionnaire that assesses the dietary intake related with dental health in children: A pilot study

BACKGROUND AND AIMS

This study aimed to develop a validated and reliable food frequency questionnaire (FFQ) that assess dietary intake related with dental health in children.

METHODS

Children, two-to-nine-years old, who consulted to a paediatric dental clinic for any reason, were recruited to complete the FFQ and 24-h recall, inquired oral hygiene habits, performed oral examinations, recorded dmft(s)/DMFT(S) index, and taken anthropometric measurements. The statistical methods used for validation were Wilcoxon signed rank test, Spearman ranked correlations, weighted kappa statistic and Bland-Altman graphs were drawn. Besides, intraclass and spearman correlation coefficients calculated for the reliability.

RESULTS

A total of 120 children participated in to the first stage of the study while 70 participants completed the 4-month period. The Spearman correlation coefficient and weighted kappa values confirmed that the FFQ had moderate validation against the food records for lactose, calcium and phosphorus. Dietary fat, fibre, lactose, calcium, potassium, fluoride, magnesium, phosphorus and zinc intakes were negatively and statistically significantly correlated with DMFT and DMFS according to both FFQ and 24-h (p < 0.05, for each). Furthermore, a positive correlation between DMFT/S and dietary carbohydrate, starch, polysaccharide and sucrose intakes was obtained.

CONCLUSIONS

These results provide the preliminary evidence for the moderated reliability and validity of the FFQ; the higher DMFT and DMFS scores might be linked to lower dietary intakes of fat, fibre, lactose, calcium, potassium, fluorine, magnesium, phosphorus and zinc; and probably higher dietary intakes of carbohydrate, starch, polysaccharide and sucrose in children.

Relative validity of a glycemic index extended food-frequency questionnaire

BACKGROUND AND AIMS

The dietary glycemic index (GI) and glycemic load (GL) are increasingly recognized as important for the prevention and management of diabetes mellitus. To extend the portfolio of assessment methods for large-scale epidemiological studies, we propose a GI-specific addition to an already established FFQ.

METHODS AND RESULTS

The German version of the EPIC-FFQ was extended by GI-specific questions for major carbohydrate sources varying notably in GI (breakfast cereals, bread, pasta, rice, potato etc.). We performed relative validation analyses comparing the GI-extended FFQ to three to four 3-day weighted dietary records (3-d WDR) in 100 middle-aged individuals with diabetes mellitus participating in the German Diabetes Study (GDS). Level of agreement between the two methods was assessed by correlation and cross-classification analyses as well as Bland-Altman-Plots, conducted separately for women and men. Spearman correlation analysis for female participants suggested good agreement between the GI-extended FFQ and 3-d WDRs for energy adjusted dietary GL (r = 0.52, p = 0.0004). For both women and men, agreement with the estimations of dietary GI, GL (for men) and carbohydrates from low and higher-GI food sources from the GI-extended FFQ was acceptable (r: 0.28-0.45). Classification of the dietary GI and GL in the opposite quartile was <10% comparing the GI-extended FFQ and 3-d WDR. Bland-Altman plots suggested a tendency for an overestimation of the dietary GI from the GI-extended FFQ in the lower GI-ranges, particularly for men.

CONCLUSION

Compared to the 3-d WDR, the GI-extended FFQ showed a moderate to good relative validity for parameters of carbohydrate quality.

Developing dietary interventions as therapy for cancer

Cancer cells acquire distinct metabolic preferences based on their tissue of origin, genetic alterations and degree of interaction with systemic hormones and metabolites. These adaptations support the increased nutrient demand required for increased growth and proliferation. Diet is the major source of nutrients for tumours, yet dietary interventions lack robust evidence and are rarely prescribed by clinicians for the treatment of cancer. Well-controlled diet studies in patients with cancer are rare, and existing studies have been limited by nonspecific enrolment criteria that inappropriately grouped together subjects with disparate tumour and host metabolic profiles. This imprecision may have masked the efficacy of the intervention for appropriate candidates. Here, we review the metabolic alterations and key vulnerabilities that occur across multiple types of cancer. We describe how these vulnerabilities could potentially be targeted using dietary therapies including energy or macronutrient restriction and intermittent fasting regimens. We also discuss recent trials that highlight how dietary strategies may be combined with pharmacological therapies to treat some cancers, potentially ushering a path towards precision nutrition for cancer.

The Gut Microbiome in Parkinson’s Disease: A Longitudinal Study of the Impacts on Disease Progression and the Use of Device-Assisted Therapies

Background

Altered gut microbiome (GM) composition has been established in Parkinson’s disease (PD). However, few studies have longitudinally investigated the GM in PD, or the impact of device-assisted therapies.

Objectives

To investigate the temporal stability of GM profiles from PD patients on standard therapies and those initiating device-assisted therapies (DAT) and define multivariate models of disease and progression.

Methods

We evaluated validated clinical questionnaires and stool samples from 74 PD patients and 74 household controls (HCs) at 0, 6, and 12 months. Faster or slower disease progression was defined from levodopa equivalence dose and motor severity measures. 19 PD patients initiating Deep Brain Stimulation or Levodopa-Carbidopa Intestinal Gel were separately evaluated at 0, 6, and 12 months post-therapy initiation.

Results

Persistent underrepresentation of short-chain fatty-acid-producing bacteria, Butyricicoccus, Fusicatenibacter, Lachnospiraceae ND3007 group, and Erysipelotrichaceae UCG-003, were apparent in PD patients relative to controls. A sustained effect of DAT initiation on GM associations with PD was not observed. PD progression analysis indicated that the genus Barnesiella was underrepresented in faster progressing PD patients at t = 0 and t = 12 months. Two-stage predictive modeling, integrating microbiota abundances and nutritional profiles, improved predictive capacity (change in Area Under the Curve from 0.58 to 0.64) when assessed at Amplicon Sequence Variant taxonomic resolution.

Conclusion

We present longitudinal GM studies in PD patients, showing persistently altered GM profiles suggestive of a reduced butyrogenic production potential. DATs exerted variable GM influences across the short and longer-term. We found that specific GM profiles combined with dietary factors improved prediction of disease progression in PD patients.

Nutritional Intake and Gut Microbiome Composition Predict Parkinson's Disease

Background

Models to predict Parkinson's disease (PD) incorporating alterations of gut microbiome (GM) composition have been reported with varying success.

Objective

To assess the utility of GM compositional changes combined with macronutrient intake to develop a predictive model of PD.

Methods

We performed a cross-sectional analysis of the GM and nutritional intake in 103 PD patients and 81 household controls (HCs). GM composition was determined by 16S amplicon sequencing of the V3-V4 region of bacterial ribosomal DNA isolated from stool. To determine multivariate disease-discriminant associations, we developed two models using Random Forest and support-vector machine (SVM) methodologies.

Results

Using updated taxonomic reference, we identified significant compositional differences in the GM profiles of PD patients in association with a variety of clinical PD characteristics. Six genera were overrepresented and eight underrepresented in PD patients relative to HCs, with the largest difference being overrepresentation of Lactobacillaceae at family taxonomic level. Correlation analyses highlighted multiple associations between clinical characteristics and select taxa, whilst constipation severity, physical activity and pharmacological therapies associated with changes in beta diversity. The random forest model of PD, incorporating taxonomic data at the genus level and carbohydrate contribution to total energy demonstrated the best predictive capacity [Area under the ROC Curve (AUC) of 0.74].

Conclusion

The notable differences in GM diversity and composition when combined with clinical measures and nutritional data enabled the development of a predictive model to identify PD. These findings support the combination of GM and nutritional data as a potentially useful biomarker of PD to improve diagnosis and guide clinical management.

A Review of In Vitro Methods for Measuring the Glycemic Index of Single Foods: Understanding the Interaction of Mass Transfer and Reaction Engineering by Dimensional Analysis

The Glycemic Index (GI) has been described by an official method ISO (International Organization for Standardization) 26642:2010 for labeling purposes. The development of in vitro methods for GI measurement has faced significant challenges. Mass transfer and reaction engineering theory may assist in providing a quantitative understanding of in vitro starch digestion and glycemic response from an engineering point of view. We suggest that in vitro GI measurements should consider the mouth and the stomach in terms of fluid mechanics, mass transfer, length scale changes, and food-solvent reactions, and might consider a significant role for the intestine as an absorption system for the glucose that is generated before the intestine. Applying mass transfer and reaction engineering theory may be useful to understand quantitative studies of in vitro GI measurements. The relative importance of reactions and mass-transfer has been estimated from literature measurements through estimating the Damköhler numbers (Da), and the values estimated of this dimensionless group (0.04–2.9) suggest that both mass transfer and chemical reaction are important aspects to consider.

Dietary Patterns and Their Associations with Intermediate Age-Related Macular Degeneration in a Japanese Population

This population-based cross-sectional study investigated the influence of dietary patterns on age-related macular degeneration (AMD) in a Japanese population. The Tsuruoka Metabolomics Cohort Study enrolled a general population aged 35–74 years from among participants in annual health check-up programs in Tsuruoka City, Japan. Eating habits were assessed using a food frequency questionnaire. Principal component analysis was used to identify dietary patterns among food items. The association between quartiles of scores for each dietary pattern and intermediate AMD was assessed using multivariate logistic regression models. Of 3433 participants, 415 had intermediate AMD. We identified four principal components comprising the Vegetable-rich pattern, Varied staple food pattern, Animal-rich pattern, and Seafood-rich pattern. After adjusting for potential confounders, higher Varied staple food diet scores were associated with a lower prevalence of intermediate AMD (fourth vs. first quartile) (OR, 0.63; 95% confidence interval [CI], 0.46–0.86). A significant trend of decreasing ORs for intermediate AMD associated with increasing Varied staple food diet scores was noted (p for trend = 0.002). There was no significant association between the other dietary patterns and intermediate AMD. In a Japanese population, individuals with a dietary pattern score high in the Varied staple food pattern had a lower prevalence of intermediate AMD.

Developed and validated food frequency questionnaires in Iran: A systematic literature review

Background:

Food frequency questionnaires (FFQs) are inexpensive, easy to administer, and practical tools for dietary assessment in epidemiological studies. Several studies have investigated the validity and reproducibility of FFQs for the Iranian population. This systematic review aimed to assess the developed and validated FFQs for use in the Iranian population and compare their features and the validation studies in this regard.

Materials and Methods:

A comprehensive search was conducted in ISI Web of Knowledge, PubMed, Scopus, and Iranian databases without time constraints to retrieve the relevant English and non-English publications. Studies would be included if they were focused on the design and validation of FFQs in Iran.

Results:

In total, 782 articles were found, 22 of which met the eligibility criteria and evaluated 18 FFQs. Validation studies had been conducted on 18 out of 20 FFQs. The median of the correlation coefficients for the comparison of the FFQ intakes and the dietary reference method by nutrients varied within the range of 0.19–0.65, indicating reasonable validity. The median of the correlation coefficients for the comparison of two FFQs by nutrients was 0.28–0.85, showing appropriate reproducibility. However, low validity was observed in some nutrients and food groups, such as egg, legumes, iron, folate, and α-tocopherol. In seven studies, biomarkers were used for the assessment of nutrient intake using an FFQ with the median correlation coefficient of −0.07–0.42. In addition, the quality of methodology was evaluated in the FFQ validation studies, with 18 out of 20 studies reporting good and excellent quality.

Conclusion:

Although the FFQs used to assess the dietary intake of the Iranian population have different features, they have acceptable validity and reproducibility. Nevertheless, some food groups and nutrients have poor validity and must be considered attentively.

A systems-biology clinical trial of a personalized multimodal lifestyle intervention for early Alzheimer's disease

INTRODUCTION

There is an urgent need to develop effective interventional treatments for people with Alzheimer's disease (AD). AD results from a complex multi-decade interplay of multiple interacting dysfunctional biological systems that have not yet been fully elucidated. Epidemiological studies have linked several modifiable lifestyle factors with increased incidence for AD. Because monotherapies have failed to prevent or ameliorate AD, interventional studies should deploy multiple, targeted interventions that address the dysfunctional systems that give rise to AD.

METHODS

This randomized controlled trial (RCT) will examine the efficacy of a 12-month personalized, multimodal, lifestyle intervention in 60 mild cognitive impairment (MCI) and early stage AD patients (aged 50+, amyloid positivity). Both groups receive data-driven, lifestyle recommendations designed to target multiple systemic pathways implicated in AD. One group receives these personalized recommendations without coaching. The other group receives personalized recommendations with health coaching, dietary counseling, exercise training, cognitive stimulation, and nutritional supplements. We collect clinical, proteomic, metabolomic, neuroimaging, and genetic data to fuel systems-biology analyses. We will examine effects on cognition and hippocampal volume. The overarching goal of the study is to longitudinally track biological systems implicated in AD to reveal the dynamics between these systems during the intervention to understand differences in treatment response.

RESULTS

We have developed and implemented a protocol for a personalized, multimodal intervention program for early AD patients. We began enrollment in September 2019; we have enrolled a third of our target (20 of 60) with a 95% retention and 86% compliance rate.

DISCUSSION

This study presents a paradigm shift in designing multimodal, lifestyle interventions to reduce cognitive decline, and how to elucidate the biological systems being targeted. Analytical efforts to explain mechanistic or causal underpinnings of individual trajectories and the interplay between multi-omic variables will inform the design of future hypotheses and development of effective precision medicine trials.

Development and Validation of a Mobile Phone Application Developed for Measuring Dietary Fiber Intake

We have developed a mobile phone application for measuring the intake of dietary fiber and validated the ability of the application to accurately capture this intake against measurements registered by a dietary record. We also investigated what food groups contributed most to the total, soluble, and insoluble dietary fiber intake. Twenty-six randomly selected Swedish women aged 35–85 years were included and randomized to either start to register dietary intake in the application or by a dietary record, during three consecutive days. After a washout period of at least two weeks, the participants used the other method. We found that the difference in measured mean fiber intake between the dietary record and the application was two grams independent of the total intake per day. A statistically significant correlation between fiber intake as measured by the two methods was found (rho = 0.65, p < 0.001). Vegetables and roots were the predominantly contributing foods to total and soluble fiber intake. Bread and crackers contributed most to insoluble fiber intake. In conclusion, the application may be considered as a useful and easy-to-use method to measure dietary fiber intake.

The impact of device-assisted therapies on the gut microbiome in Parkinson's disease

BACKGROUND

Microbiome feedbacks are proposed to influence Parkinson's disease (PD) pathophysiology. A number of studies have evaluated the impact of oral medication on the gut microbiome (GM) in PD. However, the influence of PD device-assisted therapies (DATs) on the GM remains to be investigated.

OBJECTIVES

To profile acute gut microbial community alterations in response to PD DAT initiation.

METHODS

Clinical data and stool samples were collected from 21 PD patients initiating either deep brain stimulation (DBS) or levodopa-carbidopa intestinal gel (LCIG) and ten spousal healthy control (HC) subjects. 16S amplicon sequencing of stool DNA enabled comparison of temporal GM stability between groups and with clinical measures, including disease alterations relative to therapy initiation.

RESULTS

We assessed GM response to therapy in the PD group by comparing pre-therapy (- 2 and 0 weeks) with post-therapy initiation timepoints (+ 2 and + 4 weeks) and HCs at baseline (0 weeks). Altered GM compositions were noted between the PD and HC groups at various taxonomic levels, including specific differences for DBS (overrepresentation of Clostridium_XlVa, Bilophila, Parabacteroides, Pseudoflavonifractor and underrepresentation of Dorea) and LCIG therapy (overrepresentation of Pseudoflavonifractor, Escherichia/Shigella, and underrepresentation of Gemmiger). Beta diversity changes were also found over the 4 week post-treatment initiation period.

CONCLUSIONS

We report on initial short-term GM changes in response to the initiation of PD DATs. Prior to the introduction of the DAT, a PD-associated GM was observed. Following initiation of DAT, several DAT-specific changes in GM composition were identified, suggesting DATs can influence the GM in PD.

Development and validity of semi-quantitative food frequency questionnaire as a new research tool for sugar intake assessment among Indonesian adolescents

Robust evidence has shown that sugar is a major contributor to obesity and Non-Communicable Diseases (NCDs). However, there have not been sufficient tools to estimate sugar intakes. Therefore, developing a new and valid tool to assess sugar intake, based on cultural eating habits, is crucial. The study was done in two phases; the first focused on the development of Semi-quantitative Food Frequency Questionnaire (SFFQ), and the second focused on researching the validity of the questionnaire. Food items in the SFFQ were selected from the latest national survey review, exploratory survey, and food market observation. Forty-nine food items were included in the final SFFQ with five open-ended questions for fruit groups. One hundred and six adolescents aged 15-17 years participated in the study. The total sugar intake among the adolescents was 58.80 g/day (52.7 g sucrose; 1.47 g fructose; 1.49 glucose) which contributed to 11.6% of the total energy intake per day. The reliability analysis showed a good agreement between the two administered SFFQs in a one-month interval. The relative validity results, using 6-days food diaries as a reference method, demonstrated a superior ability to rank individuals into the same and adjacent classification and only <10% gross misclassification in all sugar intakes. The developed SFFQ in turn has been proven to have moderate to good validity and be applicable for a larger epidemiological study.

Increased Added Sugar Consumption Is Common in Parkinson's Disease

Objectives: There is limited information about the dietary habits of patients with Parkinson's Disease (PD), or associations of diet with clinical PD features. We report on nutritional intake in an Australian PD cohort.

Methods: 103 PD patients and 81 healthy controls (HCs) completed a validated, semi-quantitative food frequency questionnaire. Food and nutrient intake was quantified, with consideration of micronutrients and macronutrients (energy, protein, carbohydrate, fat, fibre, and added sugar). Participants also completed PD-validated non-motor symptom questionnaires to determine any relationships between dietary intake and clinical disease features.

Results: Mean daily energy intake did not differ considerably between PD patients and HCs (11,131 kJ/day vs. 10,188 kJ/day, p = 0.241). However, PD patients reported greater total carbohydrate intake (279 g/day vs. 232 g/day, p = 0.034). This was largely attributable to increased daily sugar intake (153 g/day vs. 119 g/day, p = 0.003) and in particular free sugars (61 g/day vs. 41 g/day, p = 0.001). PD patients who (1) experienced chronic pain, (2) were depressed, or (3) reported an impulse control disorder, consumed more total sugars than HCs (all p < 0.05). Increased sugar consumption was associated with an increase in non-motor symptoms, including poorer quality of life, increased constipation severity and greater daily levodopa dose requirement.

Conclusions: We provide clinically important insights into the dietary habits of PD patients that may inform simple dietary modifications that could alleviate disease symptoms and severity. The results of this study support clinician led promotion of healthy eating and careful management of patient nutrition as part of routine care.

Validation of estimated glycaemic index and glycaemic load, stratified by race, in the Adventist Health Study-2 (AHS-2)

OBJECTIVE

Few studies have validated FFQ estimates of dietary glycaemic index (GI) and load (GL). We investigated how well our estimates of overall GI and GL from FFQs correlate with estimates from repeated 24 h recall data to validate overall GI and GL in the Adventist Health Study-2 (AHS-2).

DESIGN

The AHS-2 is a prospective population-based cohort of 95 873 Seventh-day Adventist adult church members enrolled from 2002 to 2007 to investigate diet, cancer and mortality.

SETTING

A 204-item FFQ was used to assess race- and gender-specific validity of GI and GL and 24 h recall data, from the calibration sub-study, were used as the reference.

PARTICIPANTS

The 734 calibration study participants were randomly selected by church and included approximately equal numbers of blacks and whites but were otherwise similar to the whole cohort with respect to gender, age, education and vegetarian status.

RESULTS

The deattenuated correlation coefficients for overall GI ranged from 0·19 (95 % CI -0·06, 0·53) in black men to 0·46 (95 % CI 0·40, 0·60) in black women, with both non-black men and women falling between those values (0·45 (95 % CI 0·35, 0·65) and 0·38 (95 % CI 0·27, 0·57), respectively). GL correlations were somewhat higher for all study participants. When looking at the entire cohort, the deattenuated validity correlation value for overall GI was (r 0·38, 95 % CI 0·36, 0·47) and GL was (r 0·39, 95 % CI 0·34, 0·49).

CONCLUSIONS

Our findings support the cautious use of our FFQ in epidemiological studies when assessing associations of overall GI and GL with disease risk. However, observed differences by race should be considered when interpreting results.

The Role of Epidemiological Evidence from Prospective Population Studies in Shaping Dietary Approaches to Therapy in Crohn's Disease

SCOPE

The concept that dietary factors are key risk and preventive agents in the development of Crohn's disease (CD), while widely believed and supported by epidemiological evidence, has yet to lead to clear identification of those factors through clinical trials. The aims are to examine the strength of the epidemiological evidence of diet and its association with CD, examine how interpretation of mostly epidemiological data has shaped ideas for potential dietary therapies, and to explore other factors that have driven the design of dietary clinical trials in CD.

METHODS

A literature search is performed in PubMed, Medline, EMBASE, and Google Scholar for prospective cohort studies and randomized clinical trials (RCTs) using search terms-"Crohn's disease," "diet," "risk," "remission," "treat," "cohort," "randomised."

RESULTS

Only four prospective cohort studies examine the relationship of diet and CD development, but these trials have been largely ignored by dietary RCTs in CD, which have used predominantly exclusion diets in small populations without objective endpoint assessment. Only one demonstrated clinical benefit to intestinal inflammation.

CONCLUSION

Investment in large multicenter dietary clinical trials that focus on dietary inclusions with objective endpoint assessment are needed to provide safe, sustainable dietary therapy to patients with CD.

Dietary Glycemic Index and Glycemic Load Are Not Associated with the Metabolic Syndrome in Lebanese Healthy Adults: A Cross-Sectional Study

High dietary glycemic index (GI) and glycemic load (GL) were suggested to increase the risk of metabolic syndrome (MetS). This study aims to estimate dietary GI and GL in a sample of healthy Lebanese adults and examine their association with MetS and its individual abnormalities. The study uses data from a community-based survey of 501 Lebanese urban adults. Dietary intake was assessed using a food frequency questionnaire. Biochemical, anthropometric, and blood pressure measurements were obtained. Subjects with previous diagnosis of chronic disease, metabolic abnormalities, or with incomplete data or implausible energy intakes were excluded, yielding a sample of 283. Participants were grouped into quartiles of GI and GL. Multivariate logistic regression analyses were performed. Average dietary GI and GL were estimated at 59.9 ± 8 and 209.7 ± 100.3. Participants belonging to the highest GI quartile were at increased risk of having MetS (odds ratio (OR) = 2.251, 95% CI:1.120–4.525) but this association lost significance with further adjustments. Those belonging to the second quartile of GI had significantly lower odds of having hyperglycemia (OR: 0.380, 95% CI:0.174–0.833). No associations were detected between GL and MetS. The study contributes to the body of evidence discussing the relationship between GI, GL, and MetS, in a nutrition transition context.

Evaluation of a Novel Tool for Screening Inadequate Food Intake in Age-Related Macular Degeneration Patients

Diet assessment tools provide valuable nutrition information in research and clinical settings. With growing evidence supporting dietary modification to delay development and progression of age-related macular degeneration (AMD), an AMD-specific diet assessment tool could encourage eye-care practitioners to refer patients in need of further dietary behavioural support to a dietitian and/or support network. Therefore, the aim of this study was to evaluate clinical use of a novel, short dietary questionnaire (SDQ-AMD) to screen for inadequate food intake in AMD patients by comparing it against a validated food frequency questionnaire (FFQ). Recruitment sources included Sydney-based private eye clinics and research databases (N = 155; 57% female; 78 ± 8 years). Scoring criteria based on the Australian Dietary Guidelines and dietary recommendations for AMD in literature were developed and applied to dietary data from the FFQ and SDQ-AMD. Bland-Altman plot of difference suggests agreement between the FFQ and SDQ-AMD as most mean difference scores were within the 95% CI (6.91, -9.94), and no significant bias between the scores as the mean score increased ((regression equation: y = 0.11x - 2.60) (95% CI: -0.058, 0.275, p-value = 0.20)). Scores were also significantly correlated (0.57, p ≤ 0.0001). The SDQ-AMD shows potential as a diet screening tool for clinical use, however, additional studies are warranted to validate the SDQ-AMD.

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 now over a decade ago that a published meta-analysis used a predefined standard to identify valid studies. Considering valid studies only, and using random effects dose–response meta-analysis (DRM) while withdrawing spurious results (p < 0.05), we ascertained whether these relations would 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). The combined T2D–GI RR was 1.27 (1.15–1.40) (p < 0.001, n = 10 studies) per 10 units GI, while that for the 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 2000 kcal diet, respectively. In conclusion, among adults initially in good health, diets higher in GI or GL were robustly associated with incident T2D. Together with mechanistic and other data, this supports 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 GL are substantial food markers predicting the development of T2D worldwide, for persons of European ancestry and of East Asian ancestry.

Maternal Dietary Glycemic and Insulinemic Indexes Are Not Associated with Birth Outcomes or Childhood Adiposity at 5 Years of Age in an Irish Cohort Study

BACKGROUND

High maternal dietary glycemic index (GI) and glycemic load (GL) may be associated with adverse offspring birth and postnatal adiposity outcomes through metabolic programming, but the evidence thus far, mainly from studies conducted in high-risk pregnant populations, has been inconclusive. No study has examined the influence of maternal insulin demand [measured by food insulinemic index (II) and insulinemic load (IL)] on offspring outcomes.

OBJECTIVES

We investigated associations between maternal GI, GL, II, and IL and offspring birth outcomes and postnatal adiposity in a general pregnant population.

METHODS

The study was based on data from 842 mother-child pairs from the Lifeways prospective cohort study in Ireland. Through the use of standard methodology, maternal GI, GL, II, and IL were derived from dietary information obtained via a validated food-frequency questionnaire in early pregnancy (12-16 wk). Birth outcomes were abstracted from hospital records. At 5-y follow-up, children's body mass index (BMI) and waist circumference were measured. Associations were assessed through the use of multivariable-adjusted regression analysis.

RESULTS

Mothers had a mean ± SD age of 30.3 ± 5.7 y and a mean BMI (kg/m2) of 23.9 ± 4.2. The mean ± SD for dietary glycemic and insulinemic indexes were: GI = 58.9 ± 4.4; GL = 152 ± 49; II = 57.4 ± 14.5; IL = 673 ± 267. After adjustment for confounders, no consistent associations were observed between maternal GI, GL, II, and IL and birth outcomes including birth weight, macrosomia, gestational age, and postterm births. Similarly, no association was observed with BMI and waist circumference z scores and childhood obesity (general and central) at 5-y follow-up. There was no evidence of a nonlinear relation between the studied indexes and outcomes.

CONCLUSIONS

We observed no clear relation between maternal GI, GL, II, and IL and offspring birth outcomes and childhood obesity in a general pregnant population.

The Glycaemic Index-Food-Frequency Questionnaire: Development and Validation of a Food Frequency Questionnaire Designed to Estimate the Dietary Intake of Glycaemic Index and Glycaemic Load: An Effort by the PREVIEW Consortium

Dietary glycaemic index (GI) and glycaemic load (GL) are indices used to quantify the effect of carbohydrate quality and quantity on postprandial glycaemia. GI/GL-health associations are widely studied but data on the validity of integrated GI/GL measurements are scarce. We evaluated the performance of a food-frequency questionnaire (FFQ) specifically developed to assess GI/GL. In total, 263 Dutch men and 212 women (aged 55 ± 11 years) completed a 58-item GI-FFQ, an 183-item general-FFQ and a 2-day 24 h-recall and donated blood for glycated haemoglobin (HbA1c) determination. The level of agreement between these methods was evaluated by (1) cross-classification, (2) correlations and (3) Bland and Altman plots. The three dietary assessment methods provided comparable mean intake estimates for total carbohydrates (range: 214–237 g/day), mono/disaccharides (100–107 g/day), polysaccharides (114–132 g/day), as well as bread, breakfast cereals, potatoes, pasta, rice, fruit, dairy, cakes/cookies and sweets. Mean (±SD) GI estimates were also comparable between the GI-FFQ (54 ± 3), general-FFQ (53 ± 4) and 24 h-recalls (53 ± 5). Mean (±SD) GI-FFQ GL (117 ± 37) was slightly lower than the general-FFQ GL (126 ± 38) and 24 h-recalls GL (127 ± 37). Classification of GI in quartiles was identical for the GI-FFQ and general-FFQ for 43% of the population (r = 0.58) and with 24 h-recalls for 35% of the population (de-attenuated r = 0.64). For GL, this was 48% (r = 0.65) and 44% (de-attenuated r = 0.74). Correlations between GI and HbA1c were low (r = −0.09 for GI-FFQ, r = −0.04 for general-FFQ and r = 0.07 for 24 h-recalls). In conclusion, compared to a general-FFQ and 24 h-recalls, the GI-FFQ showed a moderate to good relative validity for carbohydrates, carbohydrate-rich foods and GI/GL. No metric predicted HbA1c.

Carbohydrate nutrition variables and risk of disability in instrumental activities of daily living

PURPOSE

We aimed to examine the prospective association between dietary glycemic index (GI) and glycemic load (GL) of foods consumed, intakes of carbohydrates and fiber, and the ability to perform activities of daily living (ADL) in older adults.

METHODS

A total of 844 participants from the Blue Mountains Eye Study aged 60 years or older were examined from 2002-2004 to 2007-2009. Dietary information was collected using a validated, semi-quantitative food-frequency questionnaire. The Older Americans Resources and Services activities of daily living scale were administered to assess the functional status of participants. Multivariable logistic regression analysis was performed.

RESULTS

After multivariable adjustment, participants who were in the second and third quartiles of energy-adjusted total fiber intake compared to those in the first quartile of intake (reference group) at baseline had reduced risk of incident impaired instrumental activities of daily living (IADL) 5 years later: OR, 0.39 (95% CI 0.22-0.70) and OR 0.54 (95% CI 0.30-0.95), respectively. Analyses that involved dichotomized total fiber intake showed that participants in the upper three quartiles of total fiber intake (> 19 g/day), compared to those in the lowest quartile of intake (≤ 19 g/day) or reference group, had reduced IADL disability risk 5 years later: OR 0.49 (95% CI 0.31-0.79). Non-significant associations were observed with total carbohydrates, GI, and GL and with risk of impaired total and basic ADL at 5-year follow-up.

CONCLUSIONS

Habitual fiber consumption might be beneficial in leading to improved health status subserving performance of instrumental daily activities, needed to function in the community.

Carbohydrate and fiber intake and the risk of premenstrual syndrome

BACKGROUND/OBJECTIVES

Women with premenstrual syndrome (PMS) are encouraged to reduce sugar and increase fiber intake to reduce symptoms. However, research supporting these recommendations is limited, and their role in PMS development is unclear. This study examines the relation between carbohydrate and fiber intake and the risk of PMS nested within the prospective Nurses' Health Study II cohort.

SUBJECTS/METHODS

Carbohydrate and fiber intake were assessed at baseline and three additional times during follow up by food frequency questionnaire. Incident cases of PMS were identified by self-reported PMS diagnosis during 14 years of follow up and validated by supplemental questionnaire (n = 1234). Women were classified as controls if they did not report PMS diagnosis during follow up and confirmed minimal or no premenstrual symptoms (n = 2426). We estimated relative risks (RR) and 95% confidence intervals (CI) using multivariable logistic regression.

RESULTS

Total carbohydrate intake 2-4 years before reference year was not associated with PMS development (RR quintile 5 versus 1 = 0.99; 95% CI = 0.74-1.33). Intakes of specific carbohydrates or fibers were not associated with PMS development, except maltose. Adjusting for body mass index, smoking, and other factors, women with the highest maltose intake (median = 3.0 g/day) had a RR of 1.45 (95% CI = 1.11-1.88) compared to those with the lowest intake (median = 1.2 g/day).

CONCLUSIONS

Overall, carbohydrate and fiber consumption was not associated with risk of PMS. As this is the first study to suggest that maltose may be associated with PMS development, further replication is needed.

Dietary flavonoid intake in older adults: how many days of dietary assessment are required and what is the impact of seasonality?

BACKGROUND

Within- and between-person variation in nutrient intake is well established, but little is known about variability in dietary flavonoid intake, including the effect of seasonality.

METHODS

Within- and between-individual variability of flavonoid intake, and intake of flavonoid subclasses was examined in older adults (n = 79; mean age 70.1 y (range: 60y-80y)), using three separate 4-day weighed food records (WFR) collected approximately 4 months apart. The effects of seasonality were also examined. Mixed-effects linear regression models were used to estimate within- and between-individual variance components for flavonoids and subclasses. The number of days of dietary assessment required for a high level of hypothetical accuracy was calculated from variance ratios.

RESULTS

Within- and between-individual variability was high for flavonoid intake, and intake of flavonoid subclasses, with variance ratios > 1. It was calculated that six days of WFR data are required for total flavonoid intake, and between 6 and 10 days was required for flavonoid subclasses. There was no effect of seasonality for total flavonoid intake or intake of flavonoid subclasses, with the exception that flavan-3-ol and flavanone intakes which were relatively low in summer, and in summer and winter, respectively.

CONCLUSION

While the effects of seasonality on total flavonoid intake may be small, within- and between-individual variation associated with flavonoid intake assessment appears to be substantial across 12 days of WFR data in older adults. It is recommended that a minimum of 6 days of weighed food records are collected to minimise the impact of within- and between-individual variability on total flavonoid intake assessments in this population.

Validity and reproducibility of a short food frequency questionnaire among patients with chronic kidney disease

BACKGROUND

A balanced diet is essential to slowing the progression of chronic kidney disease (CKD) and managing the symptoms. Currently, no tool is available to easily and quickly assess energy and macronutrient intake in patients with non end-stage CKD. We aimed to develop and evaluate the validity and reproducibility of a new short 49-item food frequency questionnaire (SFFQ) adapted to patients with CKD.

METHODS

The CKD-REIN study is a prospective cohort that enrolled 3033 patients with moderate or advanced CKD from a national sample of nephrology clinics. A sub-sample of 201 patients completed the SFFQ twice, at a one-year interval and were included in the reproducibility study. During this interval, 127 patients also completed six 24-h recalls and were included in the validity study. Main nutrient and dietary intakes were computed. Validity was evaluated by calculating crude, energy-adjusted and de-attenuated correlation coefficients (CC) between FFQ and the mean of the 24-h recall results. Bland-Altman plots were performed and cross-classification into quintiles of consumption of each nutrient and food group was computed. Reproducibility between the two SFFQs was evaluated by intraclass CC (ICC).

RESULTS

Regarding validity, CC ranged from 0.05 to 0.79 (unadjusted CC, median: 0.40) and 0.10 to 0.59 (de-attenuated CC, median: 0.35) for food group and nutrient intakes, respectively. Five of the most important nutrients of interest in CKD, i.e. protein, calcium, phosphorus, potassium, and sodium had de-attenuated CC of 0.46, 0.43, 0.39, 0.32, and 0.12, respectively. The median of classification into the same or adjacent quintiles was 68% and 65% for food and nutrient intakes, respectively, and ranged from 63% to 69% for the five nutrients mentioned before. Bland-Altman plots showed good agreement across the range of intakes. ICC ranged from 0.18 to 0.66 (median: 0.46).

CONCLUSIONS

The CKD-REIN SFFQ showed acceptable validity and reproducibility in a sample of patients with CKD, notably for CKD nutrients of importance. It can now be used in large-scale epidemiological studies to easily assess the relations between diet and CKD outcomes as well as in clinical routine. It may also serve as a basis for the development of FFQs in international CKD cohort networks.

Association between carbohydrate nutrition and prevalence of depressive symptoms in older adults

We aimed to examine the relationship between dietary glycaemic index (GI) and glycaemic load of foods consumed, intakes of carbohydrates, sugars and fibre, and the prevalence of depressive symptoms in older adults. Data collected from 2334 participants aged 55+ years and 1952 participants aged 60+ years were analysed. Dietary information was collected using a semi-quantitative FFQ. Depressive symptoms were based on antidepressant use or either the 36-Item Short-Form Survey, which included the Mental Health Index (MHI), or the Center for Epidemiologic Studies Depression-10 Scale. Participants in the highest v. lowest tertile of dietary GI intake had increased odds of depressive symptoms (assessed by the MHI scale), multivariable-adjusted OR 1·55 (95 % CI 1·12, 2·14). Participants in the highest compared with lowest tertile of fruit consumption had reduced odds of prevalent depressive symptoms, multivariable-adjusted OR 0·66 (95 % CI 0·46, 0·95). Total fibre, vegetable fibre and breads/cereal fibre intakes were all inversely associated with the prevalence of depressive symptoms, with global P values of 0·03, 0·01 and 0·03, respectively. Participants in the second v. first tertile of vegetable consumption had 41 % reduced odds of prevalent depressive symptoms, multivariable-adjusted OR 0·59 (95 % CI 0·40, 0·88). We show that dietary GI and fibre intakes as well as consumption of fruits and vegetables are associated with the prevalence of depressive symptoms.

Associations between dairy food consumption and chronic kidney disease in older adults

We aimed to assess the association between dairy product consumption and calcium intake with the prevalence and 10-year incidence of chronic kidney disease (CKD). 1185 participants aged ≥50 years at baseline were examined between 1992–4 and 2002–4. Dietary data were collected using a food frequency questionnaire, and servings of dairy food consumption were calculated. Baseline biochemistry including serum creatinine was measured. CKD was defined as Modification of Diet in Renal Disease Study estimated glomerular filtration rate <60 mL·min^−1.1.73 m⁻². Cross-sectional analysis showed that older adults in the highest quintile compared to the lowest quintile (reference group) of low/reduced fat dairy food consumption had reduced odds of CKD, multivariable-adjusted odds ratio, OR, 0.64 (95% confidence intervals, CI, 0.43–0.96). Increasing total intake of dietary calcium was associated with reduced odds of CKD (P-trend = 0.02); comparing highest versus lowest quintile: OR 0.62 (95% CI 0.42–0.92). Participants in the second versus first quintile of low/reduced fat dairy food consumption at baseline had 49% reduced risk of CKD 10 years later, OR 0.51 (95% CI 0.29–0.89). Higher consumption of low/reduced fat dairy foods was independently associated with lower risk of CKD. Additional population-based studies are warranted to confirm these findings.

Validation of a short food frequency questionnaire in Australian adults

The aim of this article is to report on the validity and internal consistency of a short food frequency questionnaire (FFQ) to measure dietary intake in Australian adults. A total of 407 individuals completed the short FFQ. The Cronbach's alpha of 0.66 indicated acceptable internal consistency for the FFQ. Content validity was measured using factor analysis showed that 35% of total variance was explained by factor analysis. The FFQ was also validated against 31 3-day food records (FR). No significant difference between average intake of energy, most macronutrients, and some micronutrients between two instruments was identified. An acceptable levels of correlation (0.39-0.69) was observed between the two instruments. Bland and Altman's plots showed relative agreement in both instruments with potential bias in measuring iron and iodine. The current FFQ can be an acceptable tool to quickly measuring dietary intake in Australian adults.

The impact of nutrients on the aging rate: A complex interaction of demographic, environmental and genetic factors

Nutrition has a strong influence on the health status of the elderly, with many dietary components associated to either an increased risk of disease or to an improvement of the quality of life and to a delay of age-related pathologies. A direct effect of a reduced caloric intake on the delay of aging phenotypes is documented in several organisms. The role of nutrients in the regulation of human lifespan is not easy to disentangle, influenced by a complex interaction of nutrition with environmental and genetic factors. The individual genetic background is fundamental for mediating the effects of nutritional components on aging. Classical genetic factors able to influence nutrient metabolism are considered those belonging to insulin/insulin growth factor (INS/IGF-1) signaling, TOR signaling and Sirtuins, but also genes involved in inflammatory/immune response and antioxidant activity can have a major role. Considering the worldwide increasing interest in nutrition to prevent age related diseases and achieve a healthy aging, in this review we will discuss this complex interaction, in the light of metabolic changes occurring with aging, with the aim of shedding a light on the enormous complexity of the metabolic scenario underlying longevity phenotype.

Dietary Glycemic Index and Glycemic Load Are Positively Associated with Risk of Developing Metabolic Syndrome in Middle-Aged and Elderly Adults

OBJECTIVES

To evaluate how glycemic index (GI) and glycemic load (GL) are associated with the metabolic syndrome (MetS) and its features in middle-aged and elderly adults at high cardiovascular risk.

DESIGN

Prospective, longitudinal, population-based cohort.

SETTING

PREvención con DIeta MEDiterránea study.

PARTICIPANTS

Men and women (N = 6,606) divided into three age groups (<65, 65-74, ≥75).

MEASUREMENTS

Energy and nutrient intake was evaluated using a validated 137-item food frequency questionnaire. MetS and its features were defined in accordance with the criteria of the American Heart Association and National Heart, Lung, and Blood Institute.

RESULTS

A positive association was observed between GI and MetS prevalence in the youngest and middle age groups for participants without diabetes mellitus, but no relationship was found for those with diabetes mellitus. During the median follow-up of 4.8 years, higher GI and GL were related to greater risk of MetS in the middle age group, independent of the presence of diabetes mellitus. Changes in dietary GI were associated with risk of developing the high fasting glucose component of the MetS in the oldest age category, and changes in dietary GL were associated with risk of developing abdominal obesity, hypertriglyceridemia, low high-density lipoprotein cholesterol, and high blood pressure in the youngest age category.

CONCLUSION

Dietary GI and GL have a potential role in the development of MetS and associated clinical features, with particular age-dependent considerations.

The Reliability and Validity of the Perceived Dietary Adherence Questionnaire for People with Type 2 Diabetes

Nutrition therapy is essential for diabetes treatment, and assessment of dietary intake can be time consuming. The purpose of this study was to develop a reliable and valid instrument to measure diabetic patients’ adherence to Canadian diabetes nutrition recommendations. Specific information derived from three, repeated 24-h dietary recalls of 64 type 2 diabetic patients, aged 59.2 ± 9.7 years, was correlated with a total score and individual items of the Perceived Dietary Adherence Questionnaire (PDAQ). Test-retest reliability was completed by 27 type 2 diabetic patients, aged 62.8 ± 8.4 years. The correlation coefficients for PDAQ items versus 24-h recalls ranged from 0.46 to 0.11. The intra-class correlation (0.78) was acceptable, indicating good reliability. The results suggest that PDAQ is a valid and reliable measure of diabetes nutrition recommendations. Because it is quick to administer and score, it may be useful as a screening tool in research and as a clinical tool to monitor dietary adherence.

Olfactory impairment in older adults is associated with poorer diet quality over 5 years

PURPOSE

Decreased smell could cause appetite suppression and malnutrition. However, there is a paucity of longitudinal data between olfaction and nutritional status in older adults. We aimed to prospectively examine the relationship between olfactory impairment and overall diet quality (reflecting adherence to dietary guidelines) in a population-based cohort of older adults.

METHODS

We used 5-year follow-up data from 557 adults (aged 60+ years at baseline) whose olfaction was measured using the San Diego Odor Identification Test (SDOIT). Dietary data were collected using a validated semiquantitative food frequency questionnaire. A total diet score (TDS) was calculated for intake of selected food groups and nutrients for each participant as described in the national dietary guidelines. Final scores ranged from 0 to 20; higher scores indicated closer adherence to dietary guidelines.

RESULTS

After adjusting for all potential confounders, older adults with moderate/severe olfactory impairment (SDOIT score ≤ 3; lower scores indicate impairment) compared with those with no olfactory impairment had significantly lower adjusted mean (±SE) TDS, 9.09 (0.40) versus 9.94 (0.10), p = 0.04. Women with moderate/severe impaired olfaction (i.e., scored poorly on the odor identification test) compared with those with normal olfaction had significantly lower adjusted mean TDS, 8.87 (0.69) versus 10.31 (0.13), p = 0.04. No associations were observed between olfaction and TDS in men.

CONCLUSIONS

Olfactory impairment in older women could signal an increased risk of poorer diet quality, defined as adherence to national dietary guidelines. Additional longitudinal studies are needed to confirm or refute the observed link between olfactory loss and overall patterns of food intake in older adults.

Smoking, antioxidant supplementation and dietary intakes among older adults with age-related macular degeneration over 10 years

We aimed to compare the micronutrient usage and other lifestyle behaviors over 10 years among those with and without age-related macular degeneration (AMD). 1612 participants aged 49+ years at baseline were re-examined over 10 years, west of Sydney, Australia. AMD was assessed from retinal photographs. Dietary data were collected using a semi-quantitative food frequency questionnaire. Smoking status was self-reported. 56 participants had any AMD at baseline, of these 25% quit smoking at 5 years and were still not smoking at 10-year follow-up. Among participants who had below the recommended intake of vitamins A, C or E supplements at baseline, those who did compared to those who did not develop late AMD over 10 years were more likely to report vitamins A (total), C or E supplement intake above the recommended intake at 10-year follow-up: multivariable-adjusted OR 4.21 (95% CI 1.65-10.73); OR 6.52 (95% CI 2.76-15.41); and OR 5.71 (95% CI 2.42-13.51), respectively. Participants with compared to without AMD did not appreciably increase fish, fruit and vegetable consumption and overall diet quality. Adherence to smoking and dietary recommendations was poor among older adults with AMD. However, uptake of antioxidant supplements increased significantly among those with late AMD.

Estimation of Flavonoid Intake in Older Australians: Secondary Data Analysis of the Blue Mountains Eye Study

Flavonoids, consumed in plant-based foods, have been linked to risk reduction of cancers, cardiovascular, and neurodegenerative diseases. The paucity of information on dietary sources and quantities of flavonoid intake in older adults limits interpretation of epidemiological studies that link flavonoid intake with health outcomes in this population. It was our aim to describe total flavonoid intake, including flavonoid subclasses, in older Australians and to identify rich and commonly consumed sources of flavonoids in this age group. Twelve days of weighed food record dietary data from a subsample of the Blue Mountains Eye Study baseline cohort study of older Australians (n = 79) was analyzed using the US Department of Agriculture flavonoid database. Mean intake of flavonoids was estimated to be 683 mg/day (SD = 507) of which flavan-3-ols contributed 92%, followed by flavonols (4%), flavanones (3%), and flavones (<1%). Black tea was the major flavonoid source, providing 89% of total flavonoid intake. No differences in intake between genders were identified. Dietary intake of flavonoids and flavonoid subclasses in older Australians is similar to the one other estimation of intake in Australian older adults and confirms the types of foods that contribute to flavonoid intake among this sample of older Australians.

Consumption of dairy products and the 15-year incidence of age-related macular degeneration

Habitual consumption of dairy products has been shown to play an important role in the prevention of several chronic diseases. We aimed to prospectively assess the relationship between the change in dairy product consumption (both regular fat and low/reduced fat) and the 15-year incidence of age-related macular degeneration (AMD). In the Blue Mountains Eye Study, 2037 participants aged 49 years or above at baseline were re-examined at follow-up in 1997-9, 2002-4 and/or 2007-9. AMD was assessed from retinal photographs. Dietary data were collected using a semi-quantitative FFQ, and servings of dairy product consumption calculated. Over the 15-year follow-up, there were 352, 268 and eighty-four incident cases of any, early and late AMD, respectively. After adjusting for age, sex, current smoking, white cell count and fish consumption, a significant linear trend (P for trend = 0·003) was observed with decreasing consumption of total dairy foods and the 15-year incidence of late AMD, comparing the lowest v. highest quintile of intake (OR 2·80, 95 % CI 1·21, 3·04). Over the 15 years, decreased consumption of reduced-fat dairy foods was associated with an increased risk of incident late AMD, comparing the lowest to highest quintile of intake (OR 3·10, 95 % CI 1·18, 8·14, P for trend = 0·04). Decreasing total dietary Ca intake over the 15 years was also associated with an increased risk of developing incident late AMD (multivariable-adjusted P for trend = 0·03). A lower consumption of dairy products (regular and low fat) and Ca was independently associated with a higher risk of developing incident late AMD in the long term. Additional cohort studies are needed to confirm these findings.

Lower dairy products and calcium intake is associated with adverse retinal vascular changes in older adults

BACKGROUND AND AIMS

Higher consumption of dairy products and calcium is likely to play a role in maintaining optimal vascular health. In this study, we aimed to explore the associations between consumption of total-, regular- and low-fat dairy foods, and total calcium intake with retinal vascular caliber.

METHODS AND RESULTS

2813 Blue Mountains Eye Study participants aged 50+ years had dietary data collected using a semi-quantitative food frequency questionnaire, and serves of dairy consumption were calculated. Fundus photographs were taken and retinal vascular caliber measured using computer-assisted techniques and summarized. After adjusting for age, sex, body mass index, smoking, mean arterial blood pressure, serum glucose, white cell count, history of diagnosed hypertension, stroke and coronary heart disease, plus retinal arteriolar caliber, participants in the lowest quintile of total dairy consumption compared to those in the remaining highest 4 quintiles had significantly wider retinal venular caliber, 227.2 versus 224.7 μm, respectively (multivariable-adjusted p = 0.002). Also, subjects in the lowest quintile of low-fat dairy product consumption versus those in the remaining quintiles of low-fat dairy intake had wider retinal venules (∼ 1.7 μm, p = 0.03) and narrower retinal arterioles (∼ 1.4 μm, p = 0.04). Participants in the lowest quintile versus highest quintile of total dietary calcium intake had ∼ 2.3 μm wider retinal venules (multivariable-adjusted p-trend = 0.02).

CONCLUSIONS

A significant association was observed between lower intake of dairy products or calcium and adverse retinal vascular signs. We cannot discount the possibility of confounding from unmeasured risk factors; hence, further studies are warranted to confirm these findings.

A better diet quality is associated with a reduced likelihood of CKD in older adults

BACKGROUND AND AIMS

Studies of diet in relation to chronic kidney disease (CKD) have focused on individual nutrients. The relationship between overall patterns of food intake and renal function has not been well explored. We aimed to investigate the associations between diet quality with the prevalence, incidence and progression of CKD in a cohort of older adults.

METHODS AND RESULTS

1952 participants aged ≥50 years at baseline were examined between 1992-1994 and 2002-2004. Dietary data were collected using a semi-quantitative food frequency questionnaire. A modified version of the Healthy Eating Index for Australians was developed to determine total diet scores (TDS). Baseline biochemistry including serum creatinine was measured. CKD was defined as MDRD estimated glomerular filtration rate (eGFR) <60 mL min⁻¹·1.73 m⁻². Participants in the highest quartile of mean TDS compared to those in the first quartile (reference), had a 41% reduced likelihood of having eGFR <60 mL min⁻¹·1.73 m⁻², [multivariable-adjusted odds ratio, OR, 0.59 (95% confidence intervals, CI, 0.41-0.85), P-trend = 0.005]. Each unit increase in TDS was associated with a 15% decrease in the odds of having prevalent CKD, multivariable-adjusted OR 0.85 (95% CI 0.74-0.97). A non-significant, inverse association between TDS and CKD incidence was observed (P-trend = 0.10).

CONCLUSION

Older adults with better diet quality had a reduced likelihood of having eGFR <60 mL min⁻¹·1.73 m⁻². Adherence to dietary guidelines were not prospectively associated with CKD incidence or progression. Further studies with adequate power are warranted to assess the longitudinal association between diet quality and CKD.

Homocysteine, folate, vitamin B-12, and 10-y incidence of age-related macular degeneration

BACKGROUND

Epidemiologic evidence of a relation between serum total homocysteine (tHcy), vitamin B-12, and folate and age-related macular degeneration (AMD) is inconsistent and unresolved.

OBJECTIVE

In this cohort study, we aimed to investigate associations between intakes and serum concentrations of folate and vitamin B-12 or serum tHcy and 10-y AMD incidence.

DESIGN

Serum folate, vitamin B-12, and tHcy were determined from blood samples drawn in 1997-1999 from cohort members aged ≥55 y. AMD was assessed in 1760 survivors from retinal photographs taken in 2002-2004 and 2007-2009. Total intakes of folate and vitamin B-12 were assessed by using a food-frequency questionnaire.

RESULTS

After adjustment for age, sex, current smoking, white blood cell count, and fish consumption, each 1-SD increase in serum tHcy was associated with increased risk of incident early and any AMD [ORs (95% CIs): 1.33 (1.09, 1.63) and 1.33 (1.11, 1.60), respectively]. Participants with a serum vitamin B-12 deficiency (<185 pmol/L) had higher risk of incident early and late AMD [ORs (95% CIs): 1.58 (1.06, 2.36) and 2.56 (1.38, 4.73), respectively]. Folate deficiency (<11 nmol/L) was associated with 75% and 89% increased risk of incident early and any AMD, respectively, 10 y later. Participants who reported supplementary vitamin B-12 intake had 47% reduced risk of incident any AMD (OR: 0.53; 95% CI: 0.33, 0.85).

CONCLUSION

Elevated serum tHcy and folate and vitamin B-12 deficiencies predicted increased risk of incident AMD, which suggests a potential role for vitamin B-12 and folate in reducing AMD risk.

Is quality of diet associated with the microvasculature? An analysis of diet quality and retinal vascular calibre in older adults

It is unknown whether diet quality is associated with microvascular structure. The present study aimed to investigate the relationship between diet quality, reflecting adherence to dietary guidelines, with retinal microvascular calibre in older adults. The dietary data of 2720 Blue Mountains Eye Study participants, aged 50+ years, were collected using a semi-quantitative FFQ. A modified version of the Healthy Eating Index for Australians was developed to determine total diet scores (TDS). Fundus photographs were taken and retinal vascular calibre measured using computer-assisted techniques and summarised. After adjusting for age, sex, BMI, mean arterial blood pressure, smoking, serum glucose, leucocyte count and history of diagnosed stroke or CHD, persons with higher TDS had healthier retinal vessels cross-sectionally, with wider retinal arteriolar calibre (by approximately 3 μm, comparing the highest with the lowest quartile of TDS, Ptrend= 0·0001) and narrower retinal venular calibre (by approximately 2·5 μm; Ptrend= 0·02). In younger subjects aged ≤ 65 years, increasing TDS (lowest to the highest quartile) was associated with healthier retinal vessels: approximately 4·4 μm wider retinal arteriolar (Ptrend< 0·0001) and approximately 2·3 μm narrower venular calibre (Ptrend= 0·03). After multivariable adjustment, however, baseline TDS were not associated with retinal arteriolar (Ptrend= 0·89) or venular calibre (Ptrend= 0·25), 5 years later. Also, baseline TDS were not associated with the 5-year change in retinal arteriolar (β = 0·14; P= 0·29) or venular calibre (β = − 0·26; P= 0·07). Greater compliance with published dietary guidelines (higher diet quality) was cross-sectionally associated with wider retinal arterioles and narrower venules, indicating better retinal microvascular health.

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.

Methodology for adding glycemic index to the National Health and Nutrition Examination Survey nutrient database

Generating valid estimates of dietary glycemic index (GI) and glycemic load (GL) has been a challenge in nutritional epidemiology. The methodologic issues may have contributed to the wide variation of GI/GL associations with health outcomes observed in existing literature. We describe a standardized methodology for assigning GI values to items in the National Health and Nutrition Examination Survey (NHANES) nutrient database using the new International Tables to develop research-driven, systematic procedures and strategies to estimate dietary GI/GL exposures of a nationally representative population sample. Nutrient databases for NHANES 2003-2006 contain information on 3,155 unique foods derived from the US Department of Agriculture National Nutrient Database for Standard Reference versions 18 and 20. Assignment of GI values were made to a subset of 2,078 carbohydrate-containing foods using systematic food item matching procedures applied to 2008 international GI tables and online data sources. Matching protocols indicated that 45.4% of foods had identical matches with existing data sources, 31.9% had similar matches, 2.5% derived GI values calculated with the formula for combination foods, 13.6% were assigned a default GI value based on low carbohydrate content, and 6.7% of GI values were based on data extrapolation. Most GI values were derived from international sources; 36.1% were from North American product information. To confirm data assignments, dietary GI and GL intakes of the NHANES 2003-2006 adult participants were estimated from two 24-hour recalls and compared with published studies. Among the 3,689 men and 4,112 women studied, mean dietary GI was 56.2 (men 56.9, women 55.5), mean dietary GL was 138.1 (men 162.1, women 116.4); the distribution of dietary GI was approximately normal. Estimates of population GI and GL compare favorably with other published literature. This methodology of adding GI values to an existing population nutrient database utilized systematic matching protocols and the latest comprehensive data sources on food composition. The database can be applied in clinical and survey research settings where there is interest in estimating individual and population dietary exposures and relating them to health outcomes.

Dietary glycemic index and the risk of birth defects

Prepregnancy diabetes and obesity have been identified as independent risk factors for several birth defects, providing support for a mechanism that involves hyperglycemia and hyperinsulinemia in the development of malformations. Data from the National Birth Defects Prevention Study from 1997 to 2007 were used to investigate the association between the maternal dietary glycemic index (DGI) and the risk of birth defects among nondiabetic women. DGI was categorized by using spline regression models and quartile distributions. Adjusted odds ratios and 95% confidence intervals were calculated. The joint effect of DGI and obesity was also examined. Among the 53 birth defects analyzed, high DGI, categorized by spline regression, was significantly associated with encephalocele (adjusted odds ratio (aOR) = 2.68), diaphragmatic hernia (aOR = 2.58), small intestinal atresia/stenosis (aOR = 2.97) including duodenal atresia/stenosis (aOR = 2.48), and atrial septal defect (aOR = 1.37). Using quartiles to categorize DGI, the authors identified associations with cleft lip with cleft palate (aOR = 1.23) and anorectal atresia/stenosis (aOR = 1.40). The joint effect of high DGI and obesity provided evidence of a synergistic effect on the risk of selected birth defects. High DGI is associated with an increased risk of a number of birth defects under study. Obesity coupled with high DGI appears to increase the risk further for some birth defects.

Does a low glycaemic index (GI) diet cost more during pregnancy?

&#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.

Glycaemic index and body fat distribution in children: the results of the ARCA project

BACKGROUND AND AIMS

Various dietary factors may play a critical role in body weight regulation. Among them, the role of glycaemic index (GI) remains a subject of debate. The present study aimed at evaluating the association between dietary GI, body mass index (BMI) and body fat distribution in school children.

METHODS AND RESULTS

3734 Italian children (M/F = 1883/1851; age range 6-11 years) were cross-sectionally screened for anthropometry (BMI, waist circumference), lifestyle and clinical history (questionnaire) and dietary habits (1-year food frequency questionnaire). Energy and macronutrients intake, dietary GI and glycaemic load (GL) were calculated. GI was directly associated with age, waist and BMI z-scores, energy, fibre and carbohydrate intake (r: from 0.080 to 0.238, P < 0.001), and negatively with fat intake (r: -0.060, P < 0.0001). BMI, waist circumference, energy intake, carbohydrate, protein and fibre intake and GL significantly increased, whilst fat intake decreased, going up across quartiles of residuals of dietary GI. At linear regression analysis, GI was associated with BMI and waist z-scores independently of age, sex, parental overweight/obesity, parental education, and energy intake, protein, fat, carbohydrate, fibre and GL residuals. In particular, GI was the sole nutritional factor among those under investigation, significantly associated with waist circumference. Controlling for covariates, the risk of overweight/obesity or of central fat distribution was almost two-folds higher in the upper quartile in comparison to the lowest quartile of dietary GI.

CONCLUSION

Dietary GI is an independent determinant of body fat distribution in children as well as of total adiposity.

Relative validity of a FFQ in measuring carbohydrate fractions, dietary glycaemic index and load: exploring the effects of subject characteristics

FFQ require validation as part of epidemiological research of diet–disease relationships. Studies exploring associations between carbohydrate type and chronic diseases are rapidly increasing, but information on the validity of carbohydrate fractions, dietary glycaemic index (GI) and the glycaemic load (GL) estimated by FFQ is scarce. Likewise, the effects of subject characteristics on FFQ validity have been poorly documented. The present study evaluates the relative validity of an 131-item FFQ in relation to two 3 d food records (FR) performed 6 months apart focusing on the intake of carbohydrate fractions, dietary GI and the GL. Furthermore, we assessed the extent to which subjects' age, education and BMI explain differences between these methods. The study sample comprised 218 men and 292 women aged 25–74 years participating in a large population-based survey in Finland. Energy-adjusted Spearman's rank correlations ranged from 0·27 (sugars) to 0·70 (lactose) for men and from 0·37 (sugars) to 0·69 (lactose) for women. On average, 73 % of the subjects were categorised into the same or adjacent distribution quintile based on the two methods. In general, the FFQ overestimated the intakes compared with FR. Especially in women, FFQ validity for some nutrients was associated with the level of intake, subjects' age and, to a lesser extent, education but not BMI. In conclusion, the FFQ appears to be reasonably valid in the assessment of carbohydrate exposure variables, but the findings show a need for adjustment of diet–disease relationships for subjects' age and education.

Use of a food frequency questionnaire to assess diets of Jamaican adults: validation and correlation with biomarkers

Background

Assessment of habitual diet is important in investigations of diet-disease relationships. Many epidemiological studies use the food frequency questionnaire (FFQ) to evaluate dietary intakes but few studies validate the instrument against biological markers. The aim of this study was to assess the validity and reproducibility of a previously validated 70-item food frequency questionnaire (FFQ) that was expanded to 120-items to assess diet - cancer relations.

Methods

Relative validity of the FFQ was assessed against twelve 24-hour recalls administered over 12 months in 70 subjects. The FFQ was repeated after one year (FFQ2) to assess reproducibility. The validity of the FFQ was evaluated by comparing nutrient and food group intakes from 24-hour recalls with the first and second FFQ. In addition, FFQ validity for cholesterol and folate were determined through correlation with biomarkers (serum cholesterol, serum folate and whole blood folate) in 159 control subjects participating in a case-control prostate cancer study.

Results

Compared to recalls the FFQ tended to overestimate energy and carbohydrate intakes but gave no differences in intake for protein and fat. Quartile agreement for energy-adjusted nutrient intakes between FFQ2 and recalls ranged from 31.8% - 77.3% for the lowest quartile and 20.8% - 81.0% in the highest quartile. Gross misclassification of nutrients was low with the exceptions of protein, vitamin E and retinol and weighted kappa values ranged from 0.33 to 0.64 for other nutrients. Validity correlations for energy-adjusted nutrients (excluding retinol) were moderate to high (0.38- 0.86). Correlation coefficients between multiple recalls and FFQ1 ranged from 0.27 (fruits) to 0.55 (red meat); the second FFQ gave somewhat higher coefficients (0.30 to 0.61). Reproducibility correlations for the nutrients ranged from 0.50 to 0.84.

Calibration of the FFQ with biochemical markers showed modest correlations with serum cholesterol (0.24), serum folate (0.25) and whole blood folate (0.33) adjusted for age, energy, body mass index and smoking.

Conclusions

The expanded FFQ had good relative validity for estimating food group and nutrient intakes (except retinol and vitamin E) and was a reliable measure of habitual intake. Associations with biomarkers were comparable to other studies.