Epidemiological assessment of diet: a comparison of a 7-day diary with a food frequency questionnaire using urinary markers of nitrogen, potassium and sodium

Twenty-Four-Hour Diet recall and Diet records compared with 24-hour urinary excretion to predict an individual's sodium consumption: A Systematic Review

This systematic literature review aimed to investigate whether 24 hour diet recall and diet records are reliable and valid ways to measure usual dietary sodium intake compared with 24 hour urinary assessment. We searched electronic databases Medline, Embase, Cinahl, Lilacs, Google Scholar and the Cochrane Library using pre-defined terms Studies were eligible for inclusion if they assessed adult humans in free-living settings, and if they included dietary assessment and 24 hours urinary collection for assessment of sodium intake in the same participants. Studies that included populations with an active disease state that might interfere with normal sodium metabolism were excluded. Results of 20 studies using 24 hour diet recall recall (including 14 validation studies) and 10 studies using food records (including six validation studies) are included in this review. Correlations between estimates from dietary assessment and urinary excretion ranged from 0.16 to 0.72 for 24 hour diet recall, and 0.11 to 0.49 for food diaries. Bland-Altman analysis in two studies of 24 hour diet recall showed poor agreement with 24 hours urinary sodium excretion. These results show that 24 hour diet recall and diet records inaccurately measure dietary sodium intake in individuals compared with the gold standard 24 hours urinary excretion. Validation studies of dietary assessment methods should include multiple days of assessment and 24 hours urine collection, use relevant food composition databases and Bland-Altman methods of analysis.

Cross-Sectional Analysis of the Correlation Between Daily Nutrient Intake Assessed by 7-Day Food Records and Biomarkers of Dietary Intake Among Participants of the NU-AGE Study

Methods for measuring diet composition and quantifying nutrient intake with sufficient validity are essential to study the association between nutrition and health outcomes and risk of diseases. 7-day food records provides a quantification of food actually and currently consumed and is interesting for its use in intervention studies to monitor diet in a short-term period and to guide participants toward changing their intakes. The objective of this study is to analyze the correlation/association between the daily intake of selected nutrients (collected by a 7-day food records plus a mineral/vitamin supplementation questionnaire) and estimates of energy expenditure as well as blood and urine biomarkers of dietary intakes in 1,140 healthy elderly subjects (65–79 years) at baseline of the NU-AGE intervention study (NCT01754012, clinicaltrials.gov). The results show that: the daily intake of energy correlated significantly with predicted total energy expenditure (pTEE) (ρ = 0.459, p < 0.001, and q < 0.001); protein intake correlated significantly with the ratio of 24 h urinary urea to creatinine excretion (ρ = 0.143 for total protein intake, ρ = 0.296 for animal protein intake, and ρ = 0.359 for protein intake/body weight, p < 0.001 and q < 0.001 for each correlation); vitamin B12 and folate intakes correlated significantly with their serum concentrations (ρ = 0.151 and ρ = 0.363, respectively; p < 0.001 and q < 0.001 for each correlation); sodium and potassium intakes correlated significantly with their 24 h urinary excretion (ρ = 0.298 and ρ = 0.123, respectively; p < 0.001 and q < 0.001 for each correlation); vitamin B12 and folate intakes were negatively associated with plasma homocysteine measure (p = 0.001 and p = 0.004, respectively); stratifying subjects by gender, the correlations between energy intake and pTEE and between potassium intake and its 24 h urinary excretion lost their significance in women. Even if the plasma and urinary levels of these nutrients depend on several factors, the significant correlations between daily reported intake of nutrients (protein, vitamin B12, folate, and sodium) and their blood/urinary markers confirmed that the 7-day food records (plus a supplementation questionnaire) provides reliable data to evaluate short-term current dietary intake in European elderly subjects and it can be exploited to guide and monitor NU-AGE participants through the shift of their diet according NU-AGE recommendations.

Validation of an easy questionnaire on the assessment of salt habit: the MINISAL-SIIA Study Program

BACKGROUND/OBJECTIVES

The aim of the present study was to validate a short questionnaire on habitual dietary salt intake, to quickly and easily identify individuals whose salt consumption exceeds recommended levels.

SUBJECTS/METHODS

A total of 1131 hypertensive subjects participating in the MINISAL-SIIA study were included in the analysis. Anthropometric indexes, blood pressure, and 24-h urinary sodium excretion (NaU) were measured. A fixed-sequence questionnaire on dietary salt intake was administered.

RESULTS

NaU was significantly associated with scores, with a linear association across categories (p for trend <0.0001). In addition, participants who achieved a total score above the median value (eight points) had significantly higher NaU than those whose score was below median (p < 0.0001). In the total sample, the prevalence of "high NaU" (NaU > 85 mmol/day) and "very high NaU" (NaU > 170 mmol/day) was 86 and 35%, respectively. The score of the questionnaire had a significant ability to detect both "high NaU"-with a specificity of 95% at the score of 10 points-and "very high NaU"-with a specificity of 99.6% at score of 13 points.

CONCLUSIONS

The main results of the study indicates that a higher score of this short questionnaire is distinctive of habitual high salt consumption in hypertensive patients.

Dietary inflammatory index in relation to obesity and body mass index: a meta-analysis

Purpose

Studies investigating the association between dietary inflammatory index (DII) and body mass index (BMI) have led to inconsistent findings. Therefore, to decisively conclude, this paper aims to clarify the relationship between DII and obesity by performing meta-analysis.

Design/methodology/approach

PubMed, Scopus and Google Scholar were searched up to July 2017 using key words selected from Medical Subject Headings and other related keywords to identify all relevant articles. In total, 22 articles were entered into the meta-analysis; 22 studies compared the mean of BMI among subjects with highest versus the lowest DII and 4 studies had data on the hazard risk (HR) or odds ratio (OR) for obesity.

Findings

A meta-analysis on included studies indicated a significant association on either mean differences (MD) in BMI (MD = 0.811; 95 per cent CI: 0.365-1.256; p: 0.0001) or obesity OR (OR: 1.310; 95 per cent CI: 1.144-1.500; p = 0.000) by comparing the highest and lowest DII categories. Between-study heterogeneity was high (Cochrane Q test, p < 0.001, I2 = 98.1 per cent, df = 21, τ2 = 0.9273), and only dietary assessment methods could explain the source of heterogeneity in which 24-h dietary recalls were homogeny (I2 = 8.4 per cent, df = 2, p = 0.335).

Originality/value

The results of the present meta-analysis suggest that adherence to high DII score increased BMI and obesity. More prospective studies in different populations are needed to better clarify this relation.

Evaluation of a short food frequency questionnaire for dietary intake assessment among children

BACKGROUND/OBJECTIVES

The objective of this study was to evaluate the performance of a short food frequency questionnaire (FFQ) to assess dietary intake at 4 and 7 years of age, against 3d food diaries (FD) and serum biomarkers, using two methods to convert the FFQ to daily intake in grams and nutrients (standard and z-score method).

SUBJECTS/METHODS

The present analysis comprises data from 2482 4-year-old children and 3511 7-year-old children, from the birth cohort Generation XXI (Porto, Portugal). To estimate daily consumption from the FFQ, the frequency response was multiplied by a standard mean portion (standard method) or adjusted with data from the FD (z-score method). The dietary intake obtained from the FFQ was compared with the FD and serum biomarkers, using Intra-Class Correlation Coefficients (ICC), de-attenuated Pearson's correlation coefficients and Bland Altman analysis.

RESULTS

In general, the mean daily food intake estimated by the z-score method had a higher agreement with the FD, than the standard method. The highest ICC was obtained for "vegetable soup" (ICC = 0.536), using the z-score method, compared to an ICC of 0.373 using the standard method. Significant correlation coefficients were observed for all nutrients; the average of correlation coefficients was 0.39 at 4 years and 0.42 at 7 years of age. For the majority of nutrients, the correlation between mean and mean difference was lower using the z-score method, in comparison with the standard method.

CONCLUSIONS

The results suggest that the FFQ is a reasonably good instrument to estimate dietary intake in children. Moreover, adjusting the FFQ portion size, by using a z-score method, seems to increase the accuracy of dietary data in children.

The relationship between sleep duration and fruit/vegetable intakes in UK adults: a cross-sectional study from the National Diet and Nutrition Survey

OBJECTIVES

There is increasing evidence to suggest an association between sleep and diet. The aim of the present study was to examine the association between sleep duration and fruit/vegetable (FV) intakes and their associated biomarkers in UK adults.

DESIGN

Cross-sectional.

SETTING

Data from The National Diet and Nutrition Survey.

PARTICIPANTS

1612 adults aged 19-65 years were included, pregnant/breastfeeding women were excluded from the analyses.

OUTCOME MEASURES

Sleep duration was assessed by self-report, and diet was assessed by 4-day food diaries, disaggregation of foods containing FV into their components was conducted to determine total FV intakes. Sleep duration was divided into: short (<7 hours/day), reference (7-8 hours/day) and long (>8 hours/day) sleep periods. Multiple regression adjusting for confounders was used for analyses where sleep duration was the exposure and FV intakes and their associated biomarkers were the outcomes. Restricted cubic spline models were developed to explore potential non-linear associations.

RESULTS

In adjusted models, long sleepers (LS) consumed on average 28 (95% CI -50 to -6, p=0.01) g/day less of total FV compared to reference sleepers (RS), whereas short sleepers (SS) consumed 24 g/day less (95% CI -42 to -6, p=0.006) and had lower levels of FV biomarkers (total carotenoids, β-carotene and lycopene) compared to RS. Restricted cubic spline models showed that the association between sleep duration and FV intakes was non-linear (p<0.001) with RS having the highest intakes compared to SS and LS. The associations between sleep duration and plasma total carotenoids (p=0.0035), plasma vitamin C (p=0.009) and lycopene (p<0.001) were non-linear with RS having the highest levels.

CONCLUSIONS

These findings show a link between sleep duration and FV consumption. This may have important implications for lifestyle and behavioural change policy.

Salt Intake of Lactating Women as Assessed by Modified Food Weighted Records

OBJECTIVE

High salt intake among lactating women can increase the risk of hypertension and cardiovascular disease in infants/offspring. However, considering the limited salt intake data in lactating women, the aims of this study were to compare the salt intake assessed by modified food weighted records (FWR) with that estimated by 24-h urinary sodium excretion and to investigate the salt intake of lactating women.

METHODS

In total, 30 lactating women aged 20-39 years who were 2 to 4 months postpartum were recruited from the cities of Tianjin and Luoyang in China. The household salt intakes of the lactating women were collected by modified FWR for 3 days. Information on the gender, age, eating behaviours and labour intensity of the family members and guests dining at home during the 3 days was recorded. Meanwhile, 24-h urine samples of lactating women were collected.

RESULTS

The salt intakes of the lactating women estimated by modified FWR and 24-h urinary sodium excretion were 8.50 ± 5.32 g/d and 9.34±3.74 g/d (t=-1.29, P=0.207), respectively, which exceeded the WHO recommendation of 5 g/d. There was a significant correlation (r=0.628, P < 0.001) between the salt intakes assessed by the two methods. A Bland-Altman plot showed no significant mean difference between the two methods (salt intake measured by 24-h urinary sodium excretion-salt intake assessed by modified FWR=0.46 g/d, P=0.207).

CONCLUSIONS

The modified FWR is a reliable tool to assess the salt intake of lactating women. The salt intake of lactating women in China remains higher than the WHO recommendation and should be restricted through further efforts.

Nutrient profiling and adherence to components of the UK national dietary guidelines association with metabolic risk factors for CVD and diabetes: Airwave Health Monitoring Study

CVD is the leading cause of death worldwide. Diet is a key modifiable component in the development of CVD. No official UK diet quality index exists for use in UK nutritional epidemiological studies. The aims of this study are to: (i) develop a diet quality index based on components of UK dietary reference values (DRV) and (ii) determine the association between the index, the existing UK nutrient profile (NP) model and a comprehensive range of cardiometabolic risk markers among a British adult population. A cross-sectional analysis was conducted using data from the Airwave Health Monitoring Study (n 5848). Dietary intake was measured by 7-d food diary and metabolic risk using waist circumference, BMI, blood lipid profile, glycated Hb (HbA1c) and blood pressure measurements. Diet quality was assessed using the novel DRV index and NP model. Associations between diet and cardiometabolic risk were analysed via multivariate linear models and logistic regression. A two-point increase in NP score was associated with total cholesterol (β -0·33 mmol/l, P<0·0001) and HbA1c (β -0·01 %, P<0·0001). A two-point increase in DRV score was associated with waist circumference (β -0·56 cm, P<0·0001), BMI (β -0·15 kg/m2, P<0·0001), total cholesterol (β -0·06 mmol/l, P<0·0001) and HbA1c (β -0·02 %, P=0·002). A one-point increase in DRV score was associated with type 2 diabetes (T2D) (OR 0·94, P=0·01) and obesity (OR 0·95, P<0·0001). The DRV index is associated with overall diet quality and risk factors for CVD and T2D, supporting its application in nutritional epidemiological studies investigating CVD risk in a UK population.

The impact of a private sector living wage intervention on consumption and cardiovascular disease risk factors in a middle income country

Background

A positive association of socioeconomic position and health is well established in high-income countries. In poorer nations, however, higher income individuals often have more cardiovascular risk factors (including obesity) than do those with less income. Our study goal was to estimate the effects of receiving a living wage (340% higher income) on short-term changes in consumption and cardiovascular risk factors among low-wage workers in a middle-income country.

Methods

This cross-sectional study matched workers at an apparel factory (n=105) in the Dominican Republic with those at a similar factory (n=99) nearby, 15 months after the intervention factory introduced a substantially higher living wage. Statistical matching on non-time varying individual characteristics (childhood health, childhood living conditions, work experience, demographic factors) strengthened causal inference. Primary outcomes were blood pressure (systolic and diastolic), pulse rate, body mass index and waist circumference. Secondary outcomes were dietary consumption and spending on services, consumables and durable goods.

Results

Receiving the living wage was associated with increased consumption of protein, dairy, soda and juice and sugars, but not with cardiovascular risk factors. Intervention factory workers spent more on grocery items and household durable goods.

Conclusions

While having a higher income in a middle-income country might be expected to increase obesity and its associated health risks, the current study found no short-term negative associations. There may be possible longer-term negative health consequences of increases in consumption of soda, juice and sugars, however. It is important to consider complementary interventions to support healthy dietary intake in areas with increasing wages.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-5052-2) contains supplementary material, which is available to authorized users.

Dietary Sodium/Potassium Intake Does Not Affect Cognitive Function or Brain Imaging Indices

BACKGROUND

Dietary sodium may influence cognitive function through its effects on cerebrovascular function and cerebral blood flow.

METHODS

The aim of this study was to evaluate the association of dietary sodium intake with cognitive decline in community-dwelling older adults. We also evaluated the associations of dietary potassium and sodium:potassium intake with cognitive decline, and associations of these nutrients with micro- and macro-structural brain magnetic resonance imaging (MRI) indices. In all, 1,194 participants in the Health Aging and Body Composition study with measurements of dietary sodium intake (food frequency questionnaire [FFQ]) and change in the modified Mini Mental State Exam (3MS) were included.

RESULTS

The age of participants was 74 ± 3 years with a mean dietary sodium intake of 2,677 ± 1,060 mg/day. During follow-up (6.9 ± 0.1 years), 340 (28%) had a clinically significant decline in 3MS score (≥1.5 SD of mean decline). After adjustment, dietary sodium intake was not associated with odds of cognitive decline (OR 0.96, 95% CI 0.50-1.84 per doubling of sodium). Similarly, potassium was not associated with cognitive decline; however, higher sodium:potassium intake was associated with increased odds of cognitive decline (OR 2.02 [95% CI 1.01-4.03] per unit increase). Neither sodium or potassium alone nor sodium:potassium were associated with micro- or macro-structural brain MRI indices. These results are limited by the use of FFQ.

CONCLUSIONS

In community-dwelling older adults, higher sodium:potassium, but not sodium or potassium intake alone, was associated with decline in cognitive function, with no associations observed with micro- and macro-structural brain MRI indices. These findings do not support reduction dietary sodium/increased potassium intake to prevent cognitive decline with aging.

Comparison of self-reported dietary intakes from the Automated Self-Administered 24-h recall, 4-d food records, and food-frequency questionnaires against recovery biomarkers

Background

A limited number of studies have evaluated self-reported dietary intakes against objective recovery biomarkers.

Objective

The aim was to compare dietary intakes of multiple Automated Self-Administered 24-h recalls (ASA24s), 4-d food records (4DFRs), and food-frequency questionnaires (FFQs) against recovery biomarkers and to estimate the prevalence of under- and overreporting.

Design

Over 12 mo, 530 men and 545 women, aged 50-74 y, were asked to complete 6 ASA24s (2011 version), 2 unweighed 4DFRs, 2 FFQs, two 24-h urine collections (biomarkers for protein, potassium, and sodium intakes), and 1 administration of doubly labeled water (biomarker for energy intake). Absolute and density-based energy-adjusted nutrient intakes were calculated. The prevalence of under- and overreporting of self-report against biomarkers was estimated.

Results

Ninety-two percent of men and 87% of women completed ≥3 ASA24s (mean ASA24s completed: 5.4 and 5.1 for men and women, respectively). Absolute intakes of energy, protein, potassium, and sodium assessed by all self-reported instruments were systematically lower than those from recovery biomarkers, with underreporting greater for energy than for other nutrients. On average, compared with the energy biomarker, intake was underestimated by 15-17% on ASA24s, 18-21% on 4DFRs, and 29-34% on FFQs. Underreporting was more prevalent on FFQs than on ASA24s and 4DFRs and among obese individuals. Mean protein and sodium densities on ASA24s, 4DFRs, and FFQs were similar to biomarker values, but potassium density on FFQs was 26-40% higher, leading to a substantial increase in the prevalence of overreporting compared with absolute potassium intake.

Conclusions

Although misreporting is present in all self-report dietary assessment tools, multiple ASA24s and a 4DFR provided the best estimates of absolute dietary intakes for these few nutrients and outperformed FFQs. Energy adjustment improved estimates from FFQs for protein and sodium but not for potassium. The ASA24, which now can be used to collect both recalls and records, is a feasible means to collect dietary data for nutrition research.

A scheme for a flexible classification of dietary and health biomarkers

Biomarkers are an efficient means to examine intakes or exposures and their biological effects and to assess system susceptibility. Aided by novel profiling technologies, the biomarker research field is undergoing rapid development and new putative biomarkers are continuously emerging in the scientific literature. However, the existing concepts for classification of biomarkers in the dietary and health area may be ambiguous, leading to uncertainty about their application. In order to better understand the potential of biomarkers and to communicate their use and application, it is imperative to have a solid scheme for biomarker classification that will provide a well-defined ontology for the field. In this manuscript, we provide an improved scheme for biomarker classification based on their intended use rather than the technology or outcomes (six subclasses are suggested: food compound intake biomarkers (FCIBs), food or food component intake biomarkers (FIBs), dietary pattern biomarkers (DPBs), food compound status biomarkers (FCSBs), effect biomarkers, physiological or health state biomarkers). The application of this scheme is described in detail for the dietary and health area and is compared with previous biomarker classification for this field of research.

Omega-3 fatty acids correlate with gut microbiome diversity and production of N-carbamylglutamate in middle aged and elderly women

Omega-3 fatty acids may influence human physiological parameters in part by affecting the gut microbiome. The aim of this study was to investigate the links between omega-3 fatty acids, gut microbiome diversity and composition and faecal metabolomic profiles in middle aged and elderly women. We analysed data from 876 twins with 16S microbiome data and DHA, total omega-3, and other circulating fatty acids. Estimated food intake of omega-3 fatty acids were obtained from food frequency questionnaires. Both total omega-3and DHA serum levels were significantly correlated with microbiome alpha diversity (Shannon index) after adjusting for confounders (DHA Beta(SE) = 0.13(0.04), P = 0.0006 total omega-3: 0.13(0.04), P = 0.001). These associations remained significant after adjusting for dietary fibre intake. We found even stronger associations between DHA and 38 operational taxonomic units (OTUs), the strongest ones being with OTUs from the Lachnospiraceae family (Beta(SE) = 0.13(0.03), P = 8 × 10^-7). Some of the associations with gut bacterial OTUs appear to be mediated by the abundance of the faecal metabolite N-carbamylglutamate. Our data indicate a link between omega-3 circulating levels/intake and microbiome composition independent of dietary fibre intake, particularly with bacteria of the Lachnospiraceae family. These data suggest the potential use of omega-3 supplementation to improve the microbiome composition.

Sodium intake and multiple sclerosis activity and progression in BENEFIT

OBJECTIVE

To assess whether a high-salt diet, as measured by urinary sodium concentration, is associated with faster conversion from clinically isolated syndrome (CIS) to multiple sclerosis (MS) and MS activity and disability.

METHODS

BENEFIT was a randomized clinical trial comparing early versus delayed interferon beta-1b treatment in 465 patients with a CIS. Each patient provided a median of 14 (interquartile range = 13-16) spot urine samples throughout the 5-year follow-up. We estimated 24-hour urine sodium excretion level at each time point using the Tanaka equations, and assessed whether sodium levels estimated from the cumulative average of the repeated measures were associated with clinical (conversion to MS, Expanded Disability Status Scale [EDSS]) and magnetic resonance imaging (MRI) outcomes.

RESULTS

Average 24-hour urine sodium levels were not associated with conversion to clinically definite MS over the 5-year follow-up (hazard ratio [HR] = 0.91, 95% confidence interval [CI] = 0.67-1.24 per 1g increase in estimated daily sodium intake), nor were they associated with clinical or MRI outcomes (new active lesions after 6 months: HR = 1.05, 95% CI = 0.97-1.13; relative change in T2 lesion volume: -0.11, 95% CI = -0.25 to 0.04; change in EDSS: -0.01, 95% CI = -0.09 to 0.08; relapse rate: HR = 0.78, 95% CI = 0.56-1.07). Results were similar in categorical analyses using quintiles.

INTERPRETATION

Our results, based on multiple assessments of urine sodium excretion over 5 years and standardized clinical and MRI follow-up, suggest that salt intake does not influence MS disease course or activity. Ann Neurol 2017;82:20-29.

Individual and Combined Effects of Dietary Factors on Risk of Incident Hypertension: Prospective Analysis From the NutriNet-Santé Cohort

Dietary intake is pointed as one of the major determinants in hypertension development. Data in the area are mostly obtained from cross-sectional studies. We aimed to investigate the prospective association between (1) individual nutritional factors and (2) adherence to the Dietary Approach to Stop Hypertension and the risk of incident hypertension in a large cohort study. We prospectively examined the incidence of hypertension among 80 426 French adults participating in the NutriNet-Santé cohort study. Self-reported sociodemographic, lifestyle health questionnaires and dietary consumption assessed by three 24-hour records were completed at baseline and yearly thereafter. Associations between quartiles (Q) of nutrients and food groups and adherence to Dietary Approach to Stop Hypertension diet and hypertension risk were assessed by multivariable Cox proportional hazards models. During a mean follow-up of 3.4±2.1 years, 2413 cases of incident hypertension were documented. Dietary intakes of sodium (Q4 versus Q1): hazard ratio (HR)=1.17 (95% confidence interval [CI], 1.02-1.35), potassium: HR=0.82 (95% CI, 0.72-0.94), animal protein: HR=1.26 (95% CI, 1.11-1.43), vegetable protein: HR=0.85 (95% CI, 0.75-0.95), fiber: HR =0.81 (95% CI, 0.71-0.93), magnesium: HR=0.77 (95% CI, 0.67-0.89), fruit and vegetables: HR=0.85 (95% CI, 0.74-0.97), whole grain: HR=0.84(95% CI, 0.76-0.93), nuts: HR=0.72 (95% CI, 0.63-0.83), and red and processed meat: HR=1.25 (95% CI, 1.11-0.42) were associated with risk of hypertension. Besides, adherence to the Dietary Approach to Stop Hypertension was strongly inversely associated with incident hypertension: (Q4 versus Q1) HR=0.66 (95% CI, 0.58-0.75). Our results confirmed the association of several nutritional factors intake and incident hypertension and highlighted that adopting a global healthy diet could strongly contribute to the prevention of hypertension.

Meal Microstructure Characterization from Sensor-Based Food Intake Detection

To avoid the pitfalls of self-reported dietary intake, wearable sensors can be used. Many food ingestion sensors offer the ability to automatically detect food intake using time resolutions that range from 23 ms to 8 min. There is no defined standard time resolution to accurately measure ingestive behavior or a meal microstructure. This paper aims to estimate the time resolution needed to accurately represent the microstructure of meals such as duration of eating episode, the duration of actual ingestion, and number of eating events. Twelve participants wore the automatic ingestion monitor (AIM) and kept a standard diet diary to report their food intake in free-living conditions for 24 h. As a reference, participants were also asked to mark food intake with a push button sampled every 0.1 s. The duration of eating episodes, duration of ingestion, and number of eating events were computed from the food diary, AIM, and the push button resampled at different time resolutions (0.1–30s). ANOVA and multiple comparison tests showed that the duration of eating episodes estimated from the diary differed significantly from that estimated by the AIM and the push button (p-value <0.001). There were no significant differences in the number of eating events for push button resolutions of 0.1, 1, and 5 s, but there were significant differences in resolutions of 10–30s (p-value <0.05). The results suggest that the desired time resolution of sensor-based food intake detection should be ≤5 s to accurately detect meal microstructure. Furthermore, the AIM provides more accurate measurement of the eating episode duration than the diet diary.

Reducing consumption of confectionery foods: A post-hoc segmentation analysis using a social cognition approach

Considering confectionary consumption behaviour this cross-sectional study used social cognition variables to identify distinct segments in terms of their motivation and efforts to decrease their consumption of such foods with the aim of informing targeted social marketing campaigns. Using Latent Class analysis on a sample of 500 adults four segments were identified: unmotivated, triers, successful actors, and thrivers. The unmotivated and triers segments reported low levels of perceived need and perceived behavioural control (PBC) in addition to high levels of habit and hedonic hunger with regards their consumption of confectionery foods. Being a younger adult was associated with higher odds of being in the unmotivated and triers segments and being female was associated with higher odds of being in the triers and successful actors segments. The findings indicate that in the absence of strong commitment to eating low amounts of confectionery foods (i.e. perceived need) people will continue to overconsume free sugars regardless of motivation to change. It is therefore necessary to identify relevant messages or 'triggers' related to sugar consumption that resonate with young adults in particular. For those motivated to change, counteracting unhealthy eating habits and the effects of hedonic hunger may necessitate changes to food environments in order to make the healthy choice more appealing and accessible.

Invited Commentary: The Contribution to the Field of Nutritional Epidemiology of the Landmark 1985 Publication by Willett et al

The semiquantitative food frequency questionnaire (FFQ) has been the primary source of dietary exposure data in epidemiology for decades. Although frequency instruments had been evaluated before the 1985 publication "Reproducibility and Validity of a Semiquantitative Food Frequency Questionnaire" by Willett et al. (Am J Epidemiol. 1985;122(1):51-65), that paper was the prototype for the development and validation of what was then a highly innovative method for collecting dietary data. This approach was adopted in nearly all subsequent cohort studies of diet and disease. The paper also catalyzed an extended scientific discourse regarding methods for validation, energy adjustment, and measurement error. It is now well established that data from FFQs and other self-reported dietary assessment instruments have both value and error and that this error should be considered in the analysis and interpretation of findings, including sensitivity analyses in which adjustment for measurement error is explored. Advances in technology make it feasible to consider collecting multiple granular short-term instruments such as recalls or records over time in addition to FFQs among all participants in large cohort studies; both provide valuable information. Without a doubt, the 1985 publication by Willett et al. provided the foundation that propelled the field of nutritional epidemiology forward, and it continues to be relevant today.

Ultra-brief non-expert-delivered defusion and acceptance exercises for food cravings: A partial replication study

Food cravings are a common barrier to losing weight. This article presents a randomised comparison of non-expert group-delivered ultra-brief defusion and acceptance interventions against a distraction control. A total of 63 participants were asked to carry a bag of chocolates for a week while trying to resist the temptation to eat them. A behavioural rebound measure was administered. Each intervention out-performed control in respect of consumption, but not cravings. These techniques may have a place in the clinical management of food cravings. We provide tentative evidence that the mechanism of action is through decreased reactivity to cravings, not through reduced frequency of cravings.

Comparability of a short food frequency questionnaire to assess diet quality: the DISCOVER study

This study aims to assess comparability of a short food frequency questionnaire (SFFQ) used in the Determinants of Suicide: Conventional and Emergent Risk Study (DISCOVER Study) with a validated comprehensive FFQ (CFFQ). A total of 127 individuals completed SFFQ and CFFQ. Healthy eating was measured using Healthy Eating Score (HES). Estimated food intake and healthy eating assessed by SFFQ was compared with the CFFQ. For most food groups and HES, the highest Spearman's rank correlation coefficients between the two FFQs were r > .60. For macro-nutrients, the correlations exceeded 0.4. Cross-classification of quantile analysis showed that participants were classified between 46% and 81% into the exact same quantiles, while 10% or less were misclassified into opposite quantiles. The Bland-Altman plots showed an acceptable level of agreement between the two dietary measurement methods. The SFFQ can be used for Canadian with psychiatric disorders to rank them based on their dietary intake.

Long-Term Adherence to Low-Sodium Diet in Patients With Heart Failure

Although following a low-sodium diet (LSD) for heart failure (HF) has been recommended for decades, little is known about factors related to long-term patient adherence. The purposes of this study were to (a) compare sodium intake and factors affecting adherence in a long-term adherent group and in a non-adherent group and (b) examine predictors of membership in the long-term adherent group. Patients with HF ( N = 74) collected 24-hr urine samples and completed the Dietary Sodium Restriction Questionnaire and the Patient Health Questionnaire-9. Long-term adherence was determined using the Stage of Dietary Behavior Change Scale. The long-term adherent group had lower sodium intake (3,086 mg vs. 4,135 mg, p = .01) and perceived more benefits from LSD than the non-adherent group. Only positive attitudes toward LSD predicted membership in the long-term adherence group (odds ratio [OR] = 1.18, p = .005). Interventions focused on enhancing positive perceptions of the benefits of an LSD may improve long-term dietary adherence in patients with HF.

Executive functioning and dietary intake: Neurocognitive correlates of fruit, vegetable, and saturated fat intake in adults with obesity

Obesity is a significant public health issue, and is associated with poor diet. Evidence suggests that eating behavior is related to individual differences in executive functioning. Poor executive functioning is associated with poorer diet (few fruits and vegetables and high saturated fat) in normal weight samples; however, the relationship between these specific dietary behaviors and executive functioning have not been investigated in adults with obesity. The current study examined the association between executive functioning and intake of saturated fat, fruits, and vegetables in an overweight/obese sample using behavioral measures of executive function and dietary recall. One-hundred-ninety overweight and obese adults completed neuropsychological assessments measuring intelligence, planning ability, and inhibitory control followed by three dietary recall assessments within a month prior to beginning a behavioral weight loss treatment program. Inhibitory control and two of the three indices of planning each independently significantly predicted fruit and vegetable consumption such that those with better inhibition and planning ability consumed more fruits and vegetables. No relationship was found between executive functioning and saturated fat intake. Results increase understanding of how executive functioning influences eating behavior in overweight and obese adults, and suggest the importance of including executive functioning training components in dietary interventions for those with obesity. Further research is needed to determine causality as diet and executive functioning may bidirectionally influence each other.

Use of the Method of Triads in the Validation of Sodium and Potassium Intake in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

INTRODUCTION

Biomarkers are a good choice to be used in the validation of food frequency questionnaire due to the independence of their random errors.

OBJECTIVE

To assess the validity of the potassium and sodium intake estimated using the Food Frequency Questionnaire ELSA-Brasil.

SUBJECTS/METHODS

A subsample of participants in the ELSA-Brasil cohort was included in this study in 2009. Sodium and potassium intake were estimated using three methods: Semi-quantitative food frequency questionnaire, 12-hour nocturnal urinary excretion and three 24-hour food records. Correlation coefficients were calculated between the methods, and the validity coefficient was calculated using the method of triads. The 95% confidence intervals for the validity coefficient were estimated using bootstrap sampling. Exact and adjacent agreement and disagreement of the estimated sodium and potassium intake quintiles were compared among three methods.

RESULTS

The sample consisted of 246 participants, aged 53±8 years, 52% of women. Validity coefficient for sodium were considered weak (рfood frequency questionnaire actual intake = 0.37 and рbiomarker actual intake = 0.21) and moderate (рfood records actual intake 0.56). The validity coefficient were higher for potassium (рfood frequency questionnaire actual intake = 0.60; рbiomarker actual intake = 0.42; рfood records actual intake = 0.79). Conclusions: The Food Frequency Questionnaire ELSA-Brasil showed good validity in estimating potassium intake in epidemiological studies. For sodium validity was weak, likely due to the non-quantification of the added salt to prepared food.

Urinary potassium excretion, renal ammoniagenesis, and risk of graft failure and mortality in renal transplant recipients

BACKGROUND

Renal transplant recipients (RTRs) have commonly been urged to limit their potassium intake during renal insufficiency and may adhere to this principle after transplantation. Importantly, in experimental animal models, low dietary potassium intake induces kidney injury through stimulation of ammoniagenesis. In humans, low potassium intake is an established risk factor for high blood pressure.

OBJECTIVE

We hypothesized that low 24-h urinary potassium excretion [UKV; urinary potassium concentration × volume], the gold standard for assessment of dietary potassium intake, represents a risk factor for graft failure and mortality in RTRs. In secondary analyses, we aimed to investigate whether these associations could be explained by ammoniagenesis, plasma potassium, or blood pressure.

DESIGN

In a prospective cohort of 705 RTRs, we assessed dietary potassium intake by a single 24-h UKV and food-frequency questionnaires. Cox regression analyses were used to investigate prospective associations with outcome.

RESULTS

We included 705 stable RTRs (mean ± SD age: 53 ± 13 y; 57% men) at 5.4 y (IQR: 1.9-12.0 y) after transplantation and 253 kidney donors. Mean ± SD UKV was 73 ± 24 mmol/24 h in RTRs compared with 85 ± 25 mmol/24 h in kidney donors. During follow-up for 3.1 y (IQR: 2.7-3.9 y), 45 RTRs developed graft failure and 83 died. RTRs in the lowest sex-specific tertile of UKV (women, <55 mmol/24 h; men, <65 mmol/24 h) had an increased risk of graft failure (HR: 3.70; 95% CI: 1.64, 8.34) and risk of mortality (HR; 2.66; 95% CI: 1.53, 4.61), independent of potential confounders. In causal path analyses, 24-h urinary ammonia excretion, plasma potassium, and blood pressure did not affect these associations.

CONCLUSIONS

Our results indicate that low UKV is associated with a higher risk of graft failure and mortality in RTRs. Specific attention for adequate potassium intake after transplantation seems warranted. This trial was registered at clinicaltrials.gov as NCT02811835.

Vitamin D Status and Bone Mineral Density is Influenced by Vitamin D Supplementation and Vitamin K1 Intake in Adults with Diabetes and Chronic Kidney Disease

PURPOSE

Patients with diabetes (DM) and chronic kidney disease (CKD) are at increased risk for suboptimal bone health. The study objective was to investigate the relationships between vitamin D (vitD), vitamin K1 (vitK₁), and calcium intake with bone mineral density (BMD) and vitamin D status in an ambulatory population with DM and CKD.

METHODS

Adults (age 18-80 years; n = 62) with DM and CKD (stages 1-4) were recruited from the Northern Alberta Renal Program. Primary outcome variables included vitD, vitK₁, and calcium intake; serum 25(OH)D, 1,25(OH)₂D; and BMD as measured by dual X-ray absorptiometry. Statistical significance was determined at P < 0.05.

RESULTS

Participants met the estimated average requirement or adequate intake for vitD, vitK₁, and calcium intake in 73% (n = 45), 66% (n = 39), and 52% (n = 31), respectively, with a combined intake of micronutrient supplementation and diet. Participants had serum 25(OH)D concentrations ≥75 nmol/L (n = 41), normal BMDs (n = 48), and 66% (n = 41/62) were taking vitD supplements (>1000 IU/D). BMD was positively influenced by serum 25(OH)D. However, serum 25(OH) ≥100 nmol/L was associated with lower BMD (absolute and T-scores) for whole-body and spine (P ≤ 0.05). VitK₁ intake (≥200 μg/day) was associated with higher whole-body and femoral-neck BMDs (absoluteand T-scores; P ≤ 0.05).

CONCLUSION

VitD status and BMD in adults with DM and CKD was influenced by vitD supplementation and vitK₁ intake.

A method for sensitivity analysis to assess the effects of measurement error in multiple exposure variables using external validation data

BACKGROUND

Measurement error in self-reported dietary intakes is known to bias the association between dietary intake and a health outcome of interest such as risk of a disease. The association can be distorted further by mismeasured confounders, leading to invalid results and conclusions. It is, however, difficult to adjust for the bias in the association when there is no internal validation data.

METHODS

We proposed a method to adjust for the bias in the diet-disease association (hereafter, association), due to measurement error in dietary intake and a mismeasured confounder, when there is no internal validation data. The method combines prior information on the validity of the self-report instrument with the observed data to adjust for the bias in the association. We compared the proposed method with the method that ignores the confounder effect, and with the method that ignores measurement errors completely. We assessed the sensitivity of the estimates to various magnitudes of measurement error, error correlations and uncertainty in the literature-reported validation data. We applied the methods to fruits and vegetables (FV) intakes, cigarette smoking (confounder) and all-cause mortality data from the European Prospective Investigation into Cancer and Nutrition study.

RESULTS

Using the proposed method resulted in about four times increase in the strength of association between FV intake and mortality. For weakly correlated errors, measurement error in the confounder minimally affected the hazard ratio estimate for FV intake. The effect was more pronounced for strong error correlations.

CONCLUSIONS

The proposed method permits sensitivity analysis on measurement error structures and accounts for uncertainties in the reported validity coefficients. The method is useful in assessing the direction and quantifying the magnitude of bias in the association due to measurement errors in the confounders.

Automatic Measurement of Chew Count and Chewing Rate during Food Intake

Research suggests that there might be a relationship between chew count as well as chewing rate and energy intake. Chewing has been used in wearable sensor systems for the automatic detection of food intake, but little work has been reported on the automatic measurement of chew count or chewing rate. This work presents a method for the automatic quantification of chewing episodes captured by a piezoelectric sensor system. The proposed method was tested on 120 meals from 30 participants using two approaches. In a semi-automatic approach, histogram-based peak detection was used to count the number of chews in manually annotated chewing segments, resulting in a mean absolute error of 10.40% ± 7.03%. In a fully automatic approach, automatic food intake recognition preceded the application of the chew counting algorithm. The sensor signal was divided into 5-s non-overlapping epochs. Leave-one-out cross-validation was used to train a artificial neural network (ANN) to classify epochs as “food intake” or “no intake” with an average F1 score of 91.09%. Chews were counted in epochs classified as food intake with a mean absolute error of 15.01% ± 11.06%. The proposed methods were compared with manual chew counts using an analysis of variance (ANOVA), which showed no statistically significant difference between the two methods. Results suggest that the proposed method can provide objective and automatic quantification of eating behavior in terms of chew counts and chewing rates.

Assessing the Accuracy of a Wrist Motion Tracking Method for Counting Bites Across Demographic and Food Variables

This paper describes a study to test the accuracy of a method that tracks wrist motion during eating to detect and count bites. The purpose was to assess its accuracy across demographic (age, gender, and ethnicity) and bite (utensil, container, hand used, and food type) variables. Data were collected in a cafeteria under normal eating conditions. A total of 271 participants ate a single meal while wearing a watch-like device to track their wrist motion. A video was simultaneously recorded of each participant and subsequently reviewed to determine the ground truth times of bites. Bite times were operationally defined as the moment when food or beverage was placed into the mouth. Food and beverage choices were not scripted or restricted. Participants were seated in groups of 2-4 and were encouraged to eat naturally. A total of 24 088 bites of 374 different food and beverage items were consumed. Overall the method for automatically detecting bites had a sensitivity of 75% with a positive predictive value of 89%. A range of 62-86% sensitivity was found across demographic variables with slower eating rates trending toward higher sensitivity. Variations in sensitivity due to food type showed a modest correlation with the total wrist motion during the bite, possibly due to an increase in head-toward-plate motion and decrease in hand-toward-mouth motion for some food types. Overall, the findings provide the largest evidence to date that the method produces a reliable automated measure of intake during unrestricted eating.

Association Between Blood Pressure and Adherence to French Dietary Guidelines

BACKGROUND

Adopting a healthy diet like the Dietary Approach to Stop Hypertension (DASH) or Mediterranean diet (MD) represents a major lifestyle for blood pressure (BP) control in general population. Nutritional policies, such as the French Nutrition and Health Program (Programme National Nutrition Santé or PNNS), have been implemented in several countries with the aims of preventing chronic diseases. The objective of our study was to investigate association between BP and adherence to PNNS guidelines compared with adherence to DASH or MD.

METHODS

We conducted a cross-sectional study in 11,302 untreated participants from the NutriNet-Santé study, a French web-based cohort study. Three validated scores reflecting adherence to PNNS guidelines, DASH diet, and MD were calculated from repeated 24-hour records. Three BP measurements using a standardized protocol were collected. Multivariate linear models were used to assess the associations between the dietary scores and BP.

RESULTS

In women, independent of age, socioeconomic status, body mass index, tobacco use, alcohol consumption, and physical activity, adherence to PNNS guidelines was inversely significantly associated with systolic BP (β = -0.63, P < 0.0001). This association was of similar amplitude that between BP and adherence to DASH-style diet (β = -0.66, P < 0.0001) or MD (β = -0.63, P = 0.0002). No significant association was found in men.

CONCLUSION

Adherence to French nutritional recommendations was found negatively associated with BP at the same magnitude as adherence to well-known dietary pattern in the prevention and treatment of hypertension.

Cancers in Australia in 2010 attributable to inadequate consumption of fruit, non-starchy vegetables and dietary fibre

Objectives

To estimate the number and proportion of cancers occurring in Australia in 2010 attributable to consumption deficits in fruit, non-starchy vegetables and dietary fibre.

Methods

We estimated the population attributable fraction (PAF) for cancers causally associated with inadequate intake of fruit and non-starchy vegetables (oral cavity, pharynx, oesophageal squamous cell carcinoma, stomach, larynx); inadequate intake of fruit (lung); and insufficient intake of fibre (colorectum). We used standard formulae incorporating prevalence of exposure (1995 National Nutrition Survey) and relative risks from independent studies.

Results

Overall, 1,555 (1.4% of all) and 311 (0.3% of all) cancers were attributable to inadequate intakes of fruit and non-starchy vegetables, respectively. A further 2,609 colorectal cancers (18% of colorectal) were attributable to insufficient fibre intake. If Australians increased their fibre intake by eating the recommended daily intakes of fruit and vegetables, an estimated 1,293 (8.8%) colorectal cancers could be prevented.

Conclusions

One in six colorectal cancer cases was attributable to inadequate intake of dietary fibre and about 1,800 cancers at other sites were attributable to insufficient fruit and non-starchy vegetable consumption.

Implications

Increasing the proportion of Australians who consume the recommended intake of fruit, vegetables and fibre could prevent up to 4% of all cancers.

A Novel Wearable Device for Food Intake and Physical Activity Recognition

Presence of speech and motion artifacts has been shown to impact the performance of wearable sensor systems used for automatic detection of food intake. This work presents a novel wearable device which can detect food intake even when the user is physically active and/or talking. The device consists of a piezoelectric strain sensor placed on the temporalis muscle, an accelerometer, and a data acquisition module connected to the temple of eyeglasses. Data from 10 participants was collected while they performed activities including quiet sitting, talking, eating while sitting, eating while walking, and walking. Piezoelectric strain sensor and accelerometer signals were divided into non-overlapping epochs of 3 s; four features were computed for each signal. To differentiate between eating and not eating, as well as between sedentary postures and physical activity, two multiclass classification approaches are presented. The first approach used a single classifier with sensor fusion and the second approach used two-stage classification. The best results were achieved when two separate linear support vector machine (SVM) classifiers were trained for food intake and activity detection, and their results were combined using a decision tree (two-stage classification) to determine the final class. This approach resulted in an average F1-score of 99.85% and area under the curve (AUC) of 0.99 for multiclass classification. With its ability to differentiate between food intake and activity level, this device may potentially be used for tracking both energy intake and energy expenditure.

A simplified approach to estimating the distribution of occasionally-consumed dietary components, applied to alcohol intake

Background

Within-person variation in dietary records can lead to biased estimates of the distribution of food intake. Quantile estimation is especially relevant in the case of skewed distributions and in the estimation of under- or over-consumption. The analysis of the intake distributions of occasionally-consumed foods presents further challenges due to the high frequency of zero records. Two-part mixed-effects models account for excess-zeros, daily variation and correlation arising from repeated individual dietary records. In practice, the application of the two-part model with random effects involves Monte Carlo (MC) simulations. However, these can be time-consuming and the precision of MC estimates depends on the size of the simulated data which can hinder reproducibility of results.

Methods

We propose a new approach based on numerical integration as an alternative to MC simulations to estimate the distribution of occasionally-consumed foods in sub-populations. The proposed approach and MC methods are compared by analysing the alcohol intake distribution in a sub-population of individuals at risk of developing metabolic syndrome.

Results

The rate of convergence of the results of MC simulations to the results of our proposed method is model-specific, depends on the number of draws from the target distribution, and is relatively slower at the tails of the distribution. Our data analyses also show that model misspecification can lead to incorrect model parameter estimates. For example, under the wrong model assumption of zero correlation between the components, one of the predictors turned out as non-significant at 5 % significance level (p-value 0.062) but it was estimated as significant in the correctly specified model (p-value 0.016).

Conclusions

The proposed approach for the analysis of the intake distributions of occasionally-consumed foods provides a quicker and more precise alternative to MC simulation methods, particularly in the estimation of under- or over-consumption. The method is readily available to non-technical users in contrast to MC methods whereby the simulation error may be substantial and difficult to evaluate.

Electronic supplementary material

The online version of this article (doi:10.1186/s12874-016-0178-3) contains supplementary material, which is available to authorized users.

Validation of Nutrient Intake Estimates Derived Using a Semi-Quantitative FFQ against 3 Day Diet Records in the Baltimore Longitudinal Study of Aging

OBJECTIVE

To examine the relative validity of a multicultural FFQ used to derive nutrient intake estimates in a community dwelling cohort of younger and older men and women compared with those derived from 3 day (3d) diet records during the same time-frame.

DESIGN

Cross-sectional analyses.

SETTING

The Baltimore Longitudinal Study of Aging (BLSA) conducted in the Baltimore, MD and District of Columbia areas.

PARTICIPANTS

A subset (n=468, aged 26 to 95 years (y), 47% female, 65% non-Hispanic white) from the BLSA, with complete data for nutrient estimates from a FFQ and 3d diet records.

MEASUREMENTS

Pearson's correlation coefficients (energy adjusted and de-attenuated) for intakes of energy and 26 nutrients estimated from the FFQ and the mean of 3d diet records were calculated in a cross-sectional analysis. Rankings of individuals based on FFQ for various nutrient intakes were compared to corresponding rankings based on the average of the 3d diet records. Bland Altman plots were examined for a visual representation of agreement between both assessment methods. All analyses were stratified by sex and age (above and below 65 y).

RESULTS

Median nutrient intake estimates tended to be higher from the FFQ compared to average 3d diet records. Energy adjusted and de-attenuated correlations between FFQ intake estimates and records ranged from 0.23 (sodium intake in men) to 0.81 (alcohol intake in women). The FFQ classified more than 70 percent of participants in either the same or adjacent quartile categories for all nutrients examined. Bland Altman plots demonstrated good agreement between the assessment methods for most nutrients.

CONCLUSIONS

This FFQ provides reasonably valid estimates of dietary intakes of younger and older participants of the BLSA.

Nutrition and the homeless: the underestimated challenge

Homelessness is present in most societies and represents a situation in which the basic needs for survival including food are often limited. It is logical to surmise that the homeless person's diet is likely to be nutritionally deficient and yet there is a relative paucity in research regarding this issue with studies varying in both their methodology and homeless population. Despite these differences, diets of the homeless are frequently characterised as high in saturated fat and deficient in fibre and certain micronutrients, all of which can have negative implications for the homeless individual's health and/or mental state. The conclusion from intervention studies is that there is no consensus as to the most effective method for assessing dietary intake. In order to address this, the present review aims to provide a greater understanding of the existing literature surrounding nutrition and the homeless and to act as a foundation from which further research can be conducted. An evaluation of the main findings and challenges surrounding the assessment of the nutritional status of the homeless will be provided followed by a review of the physical and mental consequences of the homeless diet. Current and potential interventions aimed at increasing the nutritional quality of food consumed by the homeless will be addressed with a focus on the role of the nutritional science community in assisting in this endeavour.

Urinary potassium excretion and risk of cardiovascular events

BACKGROUND

Observational studies on dietary potassium and risk of cardiovascular disease (CVD) have reported weak-to-modest inverse associations. Long-term prospective studies with multiple 24-h urinary samples for accurate estimation of habitual potassium intake, however, are scarce.

OBJECTIVE

We examined the association between urinary potassium excretion and risk of blood pressure-related cardiovascular outcomes.

DESIGN

We studied 7795 subjects free of cardiovascular events at baseline in the Prevention of Renal and Vascular End-stage Disease study, a prospective, observational cohort with oversampling of subjects with albuminuria at baseline. Main cardiovascular outcomes were CVD [including ischemic heart disease (IHD), stroke, and vascular interventions], IHD, stroke, and new-onset heart failure (HF). Potassium excretion was measured in two 24-h urine specimens at the start of the study (1997-1998) and midway through follow-up (2001-2003).

RESULTS

Baseline median urinary potassium excretion was 70 mmol/24 h (IQR: 56-84 mmol/24 h). During a median follow-up of 10.5 y (IQR: 9.9-10.8 y), a total of 641 CVD, 465 IHD, 172 stroke, and 265 HF events occurred. After adjustment for age and sex, inverse associations were observed between potassium excretion and risk [HR per each 26-mmol/24-h (1-g/d) increase; 95% CI] of CVD (0.87; 0.78, 0.97) and IHD (0.86; 0.75, 0.97), as well as nonsignificant inverse associations for risk of stroke (0.85; 0.68, 1.06) and HF (0.94; 0.80, 1.10). After further adjustment for body mass index, smoking, alcohol consumption, education, and urinary sodium and magnesium excretion, urinary potassium excretion was not statistically significantly associated with risk (multivariable-adjusted HR per 1-g/d increment; 95% CI) of CVD (0.96; 0.85, 1.09), IHD (0.90; 0.81, 1.04), stroke (1.09; 0.86, 1.39), or HF (0.99; 0.83, 1.18). No associations were observed between the sodium-to-potassium excretion ratio and risk of CVD, IHD, stroke, or HF.

CONCLUSION

In this cohort with oversampling of subjects with albuminuria at baseline, urinary potassium excretion was not independently associated with a lower risk of cardiovascular events.

Dietary Factors and Cognitive Decline

Cognitive decline is an increasingly important public health problem, with more than 100 million adults worldwide projected to develop dementia by 2050. Accordingly, there has been an increased interest in preventive strategies that diminish this risk. It has been recognized that lifestyle factors including dietary patterns, may be important in the prevention of cognitive decline and dementia in later life. Several dietary components have been examined, including antioxidants, fatty acids, and B vitamins. In addition, whole dietary eating plans, including the Mediterranean diet (MeDi), and the Dietary Approaches to Stop Hypertension (DASH) diet, with and without weight loss, have become areas of increasing interest. Although prospective epidemiological studies have observed that antioxidants, fatty acids, and B vitamins are associated with better cognitive functioning, randomized clinical trials have generally failed to confirm the value of any specific dietary component in improving neurocognition. Several randomized trials have examined the impact of changing 'whole' diets on cognitive outcomes. The MeDi and DASH diets offer promising preliminary results, but data are limited and more research in this area is needed.

The potential application of a biomarker approach for the investigation of low-calorie sweetener exposure

Low-calorie sweeteners (LCS) are commonly used as sugar substitutes in the diet to provide a desired sweet taste without increased energy intake. The number of LCS available on the market has increased considerably over the years and despite extensive evaluation of their safety prior to approval, debate continues around the effects of consumption on health. In Europe, Member States are obligated to monitor exposure to LCS and methods currently used tend to rely on self-reported dietary intake data alongside LCS concentrations in products. However, the acquisition of accurate data can be costly in terms of resources and time and are inherently imprecise. Although LCS are intensely sweet, they are chemically diverse and a limitation of many studies investigating the health effects of consumption is that they often fail to discern intakes of individual LCS. An approach which objectively assesses intakes of individual LCS would therefore allow robust investigations of their possible effects on health. Biomarker approaches have been utilised for the objective investigation of intakes of a range of dietary components and the feasibility of any such approach depends upon its validity as well as its applicability within the target population. This review aims to provide an overview of current understanding of LCS intake and explore the possibility of implementing a biomarker approach to enhance such understanding. Several commonly used LCS, once absorbed into the body, are excreted via the kidneys; therefore a urinary biomarker approach may be possible for the investigation of short-term exposure to these compounds.

Changes in Non-Enzymatic Antioxidants in the Blood Following Anaerobic Exercise in Men and Women

Purpose

The aim of this study was to compare changes in total oxidative status (TOS), total antioxidative capacity (TAC) and the concentration of VitA, VitE, VitC, uric acid (UA), reduced (GSH) and oxidized glutathione (GSSG) in blood within 24 hours following anaerobic exercise (AnEx) among men and women.

Methods

10 women and 10 men performed a 20-second bicycle sprint (AnEx). Concentrations of oxidative stress indicators were measured before AnEx and 3, 15 and 30 minutes and 1 hour afterwards. UA, GSH and GSSH were also measured 24 hours after AnEx. Lactate and H⁺ concentrations were measured before and 3 minutes after AnEx.

Results

The increase in lactate and H⁺ concentrations following AnEx was similar in both sexes. Changes in the concentrations of all oxidative stress indicators were significant and did not differ between men and women. In both sexes, TOS, TAC, TOS/TAC and VitA and VitE concentrations were the highest 3 minutes, VitC concentration was the highest 30 minutes, and UA concentration was the highest 1 hour after AnEx. GSH concentration was significantly lower than the initial concentration from 15 minutes to 24 hour after AnEx. GSSG concentration was significantly higher, while the GSH/GSSG ratio was significantly lower than the initial values 1 hour and 24 hour after AnEx.

Conclusions

With similar changes in lactate and H⁺ concentrations, AnEx induces the same changes in TAC, TOS, TOS/TAC and non-enzymatic antioxidants of low molecular weight in men and women. Oxidative stress lasted at least 24 hours after AnEx.

Vitamin D status, body composition and glycemic control in an ambulatory population with diabetes and chronic kidney disease

BACKGROUND/OBJECTIVES

To determine the interrelationships between body composition, glycemic control and vitamin D status in an ambulatory population with diabetes (DM) and chronic kidney disease (CKD).

SUBJECTS/METHODS

Adult (18-80 years) patients (n=60) with DM and stage 1-4 CKD were recruited from the Northern Alberta Renal Program. Outcome variables included body composition (absolute/regional fat (FM)/lean soft tissue/total mass, percent fat/lean/fat-free (FFM) mass), glycemic control (glycated hemoglobin (HbA1c)), vitamin D intake (dietary/supplemental) and vitamin D status (25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)2D)) measured by validated methodologies. Sarcopenia was determined as an appendicular skeletal mass/height(2) less than 7.26 kg/m(2) (males) and 5.45 kg/m(2) (females).

RESULTS

Suboptimal HbA1c (>7%), 25(OH)D (<50 nmol/l) and 1,25(OH)2D (<43 pmol/l) concentrations were present in 57, 8 and 11% of participants. Ten percent of subjects had sarcopenia. Gender/age/DM type, not CKD, significantly influenced regional/whole body composition. Females, older participants and those with type 2 DM had higher %FM. No significant interrelationships between vitamin D status and glycemic control were observed (P>0.05). Serum 25(OH)D concentrations were inversely associated with arm lean soft tissue/FFM/total mass, weight, appendicular skeletal mass, lean soft tissue/height(2), FFM/height(2), appendicular skeletal mass/height(2) and body mass index (P<0.05). Sarcopenia occurred more frequently in patients with 25(OH)D concentrations ⩾100 nmol/l. Regional/whole body %FM was inversely related to 1,25(OH)2D, not 25(OH)D.

CONCLUSIONS

Body composition, not glycemic control, is associated with vitamin D status in an ambulatory population of adults with DM and CKD.

The National Cancer Institute's Dietary Assessment Primer: A Resource for Diet Research

This monograph describes the National Cancer Institute's Dietary Assessment Primer, a web resource developed to help researchers choose the best available dietary assessment approach to achieve their research objective. All self-report instruments have error, but understanding the nature of that error can lead to better assessment, analysis, and interpretation of results. The Primer includes profiles of the major self-report dietary assessment instruments, including guidance on the best uses of each instrument; discussion of validation and measurement error generally and with respect to each instrument; guidance for choosing a dietary assessment approach for different research questions; and additional resources, such as a glossary, references, and overviews of specific/important issues in the field. This monograph also describes some future research needs in the field of dietary assessment.

Urinary Sugars--A Biomarker of Total Sugars Intake

Measurement error in self-reported sugars intake may explain the lack of consistency in the epidemiologic evidence on the association between sugars and disease risk. This review describes the development and applications of a biomarker of sugars intake, informs its future use and recommends directions for future research. Recently, 24 h urinary sucrose and fructose were suggested as a predictive biomarker for total sugars intake, based on findings from three highly controlled feeding studies conducted in the United Kingdom. From this work, a calibration equation for the biomarker that provides an unbiased measure of sugars intake was generated that has since been used in two US-based studies with free-living individuals to assess measurement error in dietary self-reports and to develop regression calibration equations that could be used in future diet-disease analyses. Further applications of the biomarker include its use as a surrogate measure of intake in diet-disease association studies. Although this biomarker has great potential and exhibits favorable characteristics, available data come from a few controlled studies with limited sample sizes conducted in the UK. Larger feeding studies conducted in different populations are needed to further explore biomarker characteristics and stability of its biases, compare its performance, and generate a unique, or population-specific biomarker calibration equations to be applied in future studies. A validated sugars biomarker is critical for informed interpretation of sugars-disease association studies.