Validation of an FFQ to assess antioxidant intake in overweight postmenopausal women

Development and Validation of a Short Food Frequency Questionnaire to Measure Dietary Intake of a Selection of Immune-Modulating Nutrients in Patients with Established Peripheral Arterial Disease

Nutrients with the ability to modulate the immune system (immune-modulating nutrients; IMN) may help prevent the development and progression of atherosclerosis, the main disease process underlying peripheral artery disease (PAD). Currently, no screening tool exists to measure IMN intake; therefore, the aim of this project is to develop and validate a short food frequency questionnaire (FFQ) that measures dietary intake of 14 nutrients with proposed immune-modulating effects, identified by the literature (copper, iron and zinc, vitamins A, C, D and E, alpha linolenic acid, total long-chain omega-3 fatty acids, arginine, glutamic acid, isoleucine, leucine and valine) in patients with established PAD. A 21-item FFQ was developed to measure average daily intake of IMNs over the past 12 months. Participants (n = 106) were recruited from Flinders Medical Centre, where they completed the FFQ followed by the reference method, a diet history reflecting usual intake over the past week. The mean age of participants was 72 years, with 83% being male (n = 88). Bland–Altman analysis resulted in a statistically non-significant p-value (p-value > 0.05) for 12 out of 14 nutrients, demonstrating good agreement between the two methods. Additionally, over 50% of nutrients had a sensitivity or specificity >70%. Consequently, the novel 21-item FFQ was determined to be a promising measure of dietary intake of 14 IMNs in patients with PAD when compared to the reference method of a diet history, and it is recommended that further investigations of the utility against biomarkers be explored in the future.

Dietary Assessment Methods to Estimate (Poly)phenol Intake in Epidemiological Studies: A Systematic Review

Nutritional epidemiological studies have frequently reported associations between higher (poly)phenol intake and a decrease in the risk or incidence of noncommunicable diseases. However, the assessment methods that have been used to quantify the intakes of these compounds in large-population samples are highly variable. This systematic review aims to characterize the methods used to assess dietary (poly)phenol intake in observational studies, report the validation status of the methods, and give recommendations on method selection and data reporting. Three databases were searched for publications that have used dietary assessment methods to measure (poly)phenol intake and 549 eligible full texts were identified. Food-frequency questionnaires were found to be the most commonly used tool to assess dietary (poly)phenol intake (73%). Published data from peer-reviewed journals were the major source of (poly)phenol content data (25%). An increasing number of studies used open-access databases such as Phenol-Explorer and USDA databases on flavonoid content since their inception, which accounted for 11% and 23% of the data sources, respectively. Only 16% of the studies reported a method that had been validated for measuring the target (poly)phenols. For future research we recommend: 1) selecting a validated dietary assessment tool according to the target compounds and target period of measurement; 2) applying and combining comprehensive (poly)phenol content databases such as USDA and Phenol-Explorer; 3) detailing the methods used to assess (poly)phenol intake, including dietary assessment method, (poly)phenol content data source; 4) follow the Strengthening the Reporting of Observational Studies in Epidemiology-Nutritional Epidemiology (STROBE-nut) framework; and 5) complementing dietary intake assessment based on questionnaires with measurement of (poly)phenols in biofluids using appropriate and validated analytical methods.

Oxidative balance score and risk of osteoporosis among postmenopausal Iranian women

To our knowledge, this is the first study to examine the association of oxidative balance score (OBS) and risk of osteoporosis. Findings suggest that a predominance of anti- over pro-oxidant exposures, as reflected by a higher OBS, is associated with lower risk of lumbar spine osteoporosis among postmenopausal Iranian women.

PURPOSE

The oxidative balance score (OBS) is a combined measure of pro- and anti-oxidant exposure status, with a higher OBS indicating a predominance of anti- over pro-oxidant exposures. We aimed to examine the potential association of OBS and risk of osteoporosis among postmenopausal Iranian women, hypothesizing that a higher OBS is associated with lower risk of postmenopausal osteoporosis.

METHODS

This cross-sectional study was conducted among 151 postmenopausal Iranian women aged 50-85 y. Bone mineral density (BMD) at lumbar spine and femoral neck was measured by dual-energy X-ray absorptiometry, and osteoporosis was defined using the WHO criteria as a BMD T-score of ≤ - 2.5 standard deviations. The OBS was calculated by combining information from 17 a-priori selected pro- and anti-oxidant components classified in the following four categories: non-dietary pro-oxidants (i.e., obesity and smoking); non-dietary anti-oxidants (i.e., physical activity); dietary pro-oxidants (i.e., saturated fatty acid, poly-unsaturated fatty acid, and iron); and dietary anti-oxidants (i.e., fiber, vitamin E, folate, vitamin C, alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein/zeaxanthin, lycopene, zinc, and selenium).

RESULTS

After controlling for several potential covariates in the multivariable-adjusted binary logistic regression analysis, subjects in the highest tertile of OBS had a lower risk of lumbar spine osteoporosis than those in the lowest tertile (odds ratio = 0.14; 95% confidence interval, 0.04-0.45; p = 0.001). The OBS was not associated with risk of femoral neck osteoporosis.

CONCLUSION

Findings suggest that a predominance of anti- over pro-oxidant exposures, as indicated by a higher OBS, is associated with lower risk of lumbar spine osteoporosis among postmenopausal Iranian women.

Twenty-five years of total antioxidant capacity measurement of foods and biological fluids: merits and limitations

This review summarises 25 years of investigations on antioxidants research in foods and biological fluids and critically analyses the merits and limitations of using the total antioxidant capacity (TAC) measurement in the metabolomic era. An enormous bulk of knowledge was produced regarding the antioxidant capacity of foods and large TAC databases were developed. A direct link between a food TAC value and any health benefit is erroneous and has led to several cases of consumer deception. However, the striking epidemiological evidence associating a high dietary TAC with some disease prevention and the availability of well-constructed TAC databases deserve attention and must be taken into account to establish the usefulness of measuring TAC in both foods and biological samples. The in vivo TAC measurement, usually performed in plasma, is influenced by many external factors, such as dietary habits, as well as environmental and behavioural factors, which are integrated towards homeostatic control by fine physiological mechanisms with high inter-individual variability. Therefore, plasma TAC cannot be considered as a unique biomarker of individual antioxidant status. However, the combined evaluation of plasma TAC with known markers of disease, individual metabolism, inflammation and genetics, as well as with markers of gut microbiota composition and activity, may lead to the identification of populations that are more responsive to food/diet TAC. In this framework, the appropriate use of TAC measurement both in food and in vivo can still provide support for the interpretation of complex phenomena and be a tool for sample screening when making a quick decision toward in-depth research investigations. © 2018 Society of Chemical Industry.

Development, validity, and reproducibility of a semiquantitative food frequency questionnaire for the assessment of antioxidant vitamins intake in Lebanon

OBJECTIVES

The growing interest in the possible role of antioxidant vitamins in many pathologies makes the methods of evaluating the intakes of these vitamins necessary. The food frequency questionnaire is the most widely used tool in epidemiologic studies and large-scale surveys to assess long-term nutritional exposure and to determine the usual intake of specific foods or nutrients. The aims of this study were to develop and investigate the validity and reproducibility of a semiquantitative food frequency questionnaire (SQFFQ) to evaluate the antioxidant vitamins intake in the Lebanese population and for use in clinical trials.

METHODS

An SQFFQ draft was built with the major sources of vitamins with antioxidant properties initially selected from food that have the higher percentages of the daily value of vitamins A, C, and E; listed in the US Department of Agriculture tables. We used food intake data that were available through a 24-h dietary recall (3 weekdays and 1 weekend day) among a subsample of 50 participants to complete the SQFFQ. We sought the major sources of the most frequently reported antioxidant vitamins, portion sizes, and percentages of the daily value of the major sources of these vitamins (developed by the US Department of Agriculture) to build a 34-item SQFFQ. The consumption frequency was coded as daily, weekly, monthly, or occasionally and one to three times or more. Five hundred Lebanese participants (the previous 50 who provided the 24 h dietary recall, along with 450 new participants) completed the questionnaire, whereas only 50 and 42 were accepted to be enrolled in the validity and reproducibility studies, respectively. To assess validity, the questionnaire was compared with the 24-h dietary recall performed on a subsample of 50 participants who already completed the SQFFQ. The reproducibility was assessed by comparing baseline SQFFQ with a second administration of the SQFFQ 3 to 5 wk later at the same dietetic clinic.

RESULTS

The means of daily consumption of vitamins A, C, and E based on the SQFFQ and the 24 h data were as follows: Vitamin A: 252.5 ± SD 958.9 versus 242.6 ± SD 580.5 mcg of retinol activity equivalents (µg RAE), Vitamin C: 86.5 ± SD 59.9 versus 85.5 ± SD 56.2 µg, and Vitamin E: 17 ± SD 7.2 versus 17.1 ± SD 7.9 µg. The Pearson correlation coefficients of the three vitamins between dietary intake estimates derived from the SQFFQ and 24-h data were, respectively, r = 0.83, 0.98, and 0.9; they were highly significant at P < 0.001. One sample t tests and Bland-Altman plots confirmed this validity. The reproducibility of the SQFFQ was assessed using the Cronbach α index that measures reliability between different components (for vitamin A: 0.994, vitamin C: 0.998, and vitamin E: 0.975). The correlation matrix (interitem correlation) showed that all elements were highly correlated (r > 0.4) and even close to 1 (for vitamin A = 0.989, vitamin C = 0.995, and vitamin E = 0.95).

CONCLUSIONS

In this study, we described the development of an SQFFQ. Based on the results, we found the SQFFQ to be valid and reproducible to assess intake of antioxidant vitamins in Lebanese adults.<END ABSTRACT>.