Water: The Cinderella Nutrient

Reproducibility and relative validity of a semi-quantitative food and beverage frequency questionnaire for Spanish children aged 3 to 11 years: the COME-Kids F&B-FQ

A reliable food and beverage frequency questionnaire (F&B-FQ) to measure dietary intakes for children across Spain is currently unavailable. Thus, we designed and assessed the reproducibility and relative validity of a new F&B-FQ in 210 Spanish children aged 3-11 years. COME-Kids F&B-FQ contained 125 items to assess the usual diet intake in the past year among children. To explore the reproducibility, caregivers answered COME-Kids F&B-FQ twice over a 15-day period (± 1 week). To evaluate the relative validity, estimates from a third COME-Kids F&B-FQ administered at 1 year of follow-up were compared with the mean estimates from 3-day dietary records (3d-DR) collected at baseline, 6 months, and after 1 year of follow-up. Reproducibility and relative validity of the COME-Kids F&B-FQ in estimating food groups and nutrients were assessed using Pearson (r) and intra-class (ICC) correlation coefficients. We used the kappa index to evaluate the agreement in repeat administrations or with the 3d-DR. We used Bland-Altman plots to identify bias across levels of intake. A total of 195 children (105 boys, 90 girls) completed the study. The reproducibility of data estimated from COME-Kids F&B-FQ was substantial with mean r and ICC being 0.65 and 0.64 for food groups and 0.63 and 0.62 for nutrients, respectively. Validation assessments comparing the FFQ and 3d-DRs showed r = 0.36 and ICC = 0.30 for food groups and r = 0.29 and ICC = 0.24 for nutrients. The mean agreement for food group reproducibility and relative validity was 86% and 65%, respectively. These estimates were 85% for reproducibility and 64% for relative validity in the case of nutrients. For reproducibility and relative validity, the overall mean kappa index was 63% and 37% for all food groups and 52% and 27% for nutrients, respectively. Bland-Altman plots showed no specific bias relating to the level of intake of nutrients and several food groups.

CONCLUSION

COME-Kids F&B-FQ showed substantial reproducibility and acceptable relative validity to assess food and beverage intake in Spanish children aged 3 to 11 years. Most children were correctly classified in relation to the intake of food groups and nutrients, and misclassification was unlikely with reference to 3d-DR.

WHAT IS KNOWN

• The estimation of dietary intake in children is complex, especially in large cohorts. • The food frequency questionnaire is a well-recognized and the most frequently used method for assessing food consumption.

WHAT IS NEW

• A new food and beverage frequency questionnaire including a beverage section and novel plant-based food items has been validated in Spanish children aged 3-11 years.

Drinking Water Source and Intake Are Associated with Distinct Gut Microbiota Signatures in US and UK Populations

BACKGROUND

The microbiome of the digestive tract exerts fundamental roles in host physiology. Extrinsic factors including lifestyle and diet are widely recognized as key drivers of gut and oral microbiome compositions. Although drinking water is among the food items consumed in the largest amount, little is known about its potential impact on the microbiome.

OBJECTIVES

We explored the associations of plain drinking water source and intake with gut and oral microbiota compositions in a population-based cohort.

METHODS

Microbiota, health, lifestyle, and food intake data were extracted from the American Gut Project public database. Associations of drinking water source (bottled, tap, filtered, or well water) and intake with global microbiota composition were evaluated using linear and logistic models adjusted for anthropometric, diet, and lifestyle factors in 3413 and 3794 individuals, respectively (fecal samples; 56% female, median [IQR] age: 48 [36-59] y; median [IQR] BMI: 23.3 [20.9-26.3] kg/m2), and in 283 and 309 individuals, respectively (oral samples).

RESULTS

Drinking water source ranked among the key contributing factors explaining the gut microbiota variation, accounting for 13% [Faith's phylogenetic diversity (Faith's PD)] and 47% (Bray-Curtis dissimilarity) of the age effect size. Drinking water source was associated with differences in gut microbiota signatures, as revealed by β diversity analyses (P < 0.05; Bray-Curtis dissimilarity, weighted UniFrac distance). Subjects drinking mostly well water had higher fecal α diversity (P < 0.05; Faith's PD, observed amplicon sequence variants), higher Dorea, and lower Bacteroides, Odoribacter, and Streptococcus than the other groups. Low water drinkers also exhibited gut microbiota differences compared with high water drinkers (P < 0.05; Bray-Curtis dissimilarity, unweighted UniFrac distance) and a higher abundance of Campylobacter. No associations were found between oral microbiota composition and drinking water consumption.

CONCLUSIONS

Our results indicate that drinking water may be an important factor in shaping the human gut microbiome and that integrating drinking water source and intake as covariates in future microbiome analyses is warranted.