Validity of a food frequency questionnaire for the estimation of total polyphenol intake estimates and its major food sources in the Japanese population: the JPHC FFQ Validation Study

Dietary Polyphenol Intake and Risk of Overall and Site-Specific Cancers: the Japan Public Health Center-based Prospective Study

BACKGROUND

Polyphenols may play a protective role in carcinogenesis through a wide range of properties, including antioxidant and anti-inflammatory. However, evidence for the association between total dietary polyphenol intake and cancer risk in Asian populations is limited.

OBJECTIVE

This population-based prospective study aimed to investigate the association between polyphenol intake and risk of overall and site-specific cancer among Japanese.

METHODS

Participants were 41,907 men and 48,268 women aged 45-74 y with no previous cancer diagnosis in the Japan Public Health Center-based Prospective Study. Dietary polyphenol intake was estimated by a 147-item food frequency questionnaire administered in 1995-1998. Participants were divided into quintiles (Q) according to intakes of total polyphenol and polyphenol from foods, not including high-polyphenolic beverages (tea, coffee, and alcoholic beverages). Hazard ratios (HRs) and 95% confidence intervals (CIs) for cancer risk were estimated using Cox proportional hazard regression models adjusted for potential confounders.

RESULTS

During a median of 15.8 y of follow-up, 12,970 incident cancer cases (7999 men and 4971 women) were identified. We did not observe associations of lower risk of overall cancer with polyphenol intake. For site-specific cancers, compared with the lowest quintile (Q1), higher total polyphenol intake was associated with a lower risk of liver cancer in men (HRQ4: 0.67; 95% CI: 0.51, 0.89, HRQ5: 0.66; 95% CI: 0.48, 0.89; P-trend = 0.003) and women (HRQ5: 0.63; 95% CI: 0.39, 1.02; P-trend = 0.003), whereas higher polyphenol intake from foods not including tea, coffee, and alcoholic beverages was associated with a lower risk of colon cancer in men (HRQ4: 0.73; 95% CI: 0.58, 0.92, HRQ5: 0.72; 95% CI: 0.54, 0.96; P-trend = 0.07).

CONCLUSIONS

The results of the present study do not support a substantial role for dietary polyphenols in overall cancer prevention. Total polyphenol may reduce the risk of liver cancer, and polyphenol from foods, not including tea, coffee, and alcoholic beverages, may reduce the risk of colon cancer.

Validation of a food frequency questionnaire for measuring dietary intake of isoflavones and lignans using the method of triads

BACKGROUND

Emerging epidemiologic evidence suggested a protective association between dietary phytoestrogens and multiple chronic diseases, although validation studies on the 2 phytoestrogen subclasses, isoflavones and lignans, estimated from food frequency questionnaires (FFQs) are lacking.

OBJECTIVES

We evaluated the performance of the FFQ for measuring isoflavone and lignan intake among 892 free-living adults in the Anhui Lifestyle Validation Study (ALVS).

METHODS

From July 2021 to July 2022, participants from the ALVS completed a 141-item FFQ and donated fasting morning urine specimens twice, 1-year apart, and completed twelve 24-h dietary recalls (24HDRs) that consisted of 4 quarterly 3 consecutive 24-h dietary recalls (i.e. 2 weekdays and 1 weekend day in each season) between the 2 FFQ assessments. The reproducibility coefficients were assessed by the intraclass correlation coefficient between estimates from the 2 FFQs. The validity coefficients (VCs) were evaluated by the method of triads to calculate correlations between estimates from dietary assessment tools and true dietary intake using biomarkers (the mean of 2 measurements of urinary concentrations of 4 isoflavone metabolites and 4 lignan metabolites), 24HDRs, and FFQs.

RESULTS

The FFQ-derived isoflavones (median: 23.6 mg/d; IQR: 12.1-41.5 mg/d) and lignans (median: 19.7 mg/d; IQR: 11.9-30.7 mg/d) showed good reproducibility with the same intraclass correlation coefficient of 0.55 (95% confidence interval [CI]: 0.46, 0.62). Estimated VCs between the FFQs and theoretical true intake were 0.65 (95% CI: 0.31, 1.00) for isoflavones and 0.48 (95% CI: 0.24, 0.86) for lignans. Compared with FFQ-based assessments, urinary biomarkers showed the same validity in assessing dietary lignans (VC: 0.48; 95% CI: 0.21, 0.88), but dietary isoflavones showed a lower VC of 0.22 (95% CI: 0.03, 0.47).

CONCLUSIONS

FFQ shows reasonable performance in measuring habitual intake of isoflavones and lignans, although urinary isoflavones are unlikely to perform as well as FFQ-based assessment of dietary isoflavones.

[Food Ingredients and Hygiene: Exploring the Functions of Food Ingredients Through Hygiene Studies]

Hygiene is a field of study that aims to "protect health" and "protect lifestyle" of people from external factors such as bacteria, poor nutrition, and toxic chemicals, as well as internal factors such as lifestyle and stress. In the early days of hygiene science in Japan, the results of nutritional epidemiology research by Dr. Kanehiro Takaki, a naval doctor who studied medicine in Kagoshima, on the prevention of beriberi, a national disease at the time, were highly regarded internationally. Since then, hygiene research on food ingredients has been vigorously pursued to expand from basic research to applied research, as exemplified by the development of the allithiamine. The symposium "Food Ingredients and Hygiene: Exploring the Functions of Food Ingredients from Hygiene" was organized by the Young Researchers Association at the 94th Annual Meeting of the Japanese Society for Hygiene (Kagoshima) to introduce recent research and examples of industry-academia collaboration. Young researchers involved in hygiene research on foods and food materials presented their recent work ranging from basic research, such as the functional evaluation of foods by animal experiments and the evaluation of the effects of polyphenols and yogurt on health, which have long been studied, to applied research leading to the commercialization of foods with useful physiological effects. This mini-review is a summary of the symposium. As the Young Researchers Association, we hope that this symposium/mini-review will encourage young researchers to become interested in various functions of food ingredients, conduct related research, and consider how to contribute their research results to society.

Age-Related Effects of Olive Oil Polyphenol Ingestion on Oxidation of Low-Density Lipoprotein in Healthy Japanese Men: A Randomized Controlled Double-Blind Crossover Trial

BACKGROUND

The function of olive oil polyphenols in suppressing the oxidation of low-density lipoprotein (LDL) is well-known in Europeans. However, it remains unclear whether olive oil polyphenols exert antioxidant effects in Japanese people.

OBJECTIVES

The objective of this study was to determine whether the ingestion of olive oil polyphenols suppresses LDL oxidation in the Japanese population and whether this effect depends on age.

METHODS

This randomized controlled double-blind crossover trial with a 2-week washout enrolled 80 healthy Japanese men aged 35-64 years. Participants ingested either 14 g of extra virgin olive oil containing 5.0 mg of olive oil polyphenols (test food) or 14 g of refined olive oil containing 0.3 mg of olive oil polyphenols (control food) for 3 weeks. The primary outcome was oxidized LDL (malondialdehyde-modified LDL; MDA-LDL). Subgroup analyses based on age (35-50 and 51-64 years) were also performed.

RESULTS

In all of the participants (35-64 years), there were no significant differences in MDA-LDL between the control and test groups. However, in the 35-50 years subgroup, ingestion of olive oil polyphenols led to a significantly larger reduction in MDA-LDL as compared with the control group (p < 0.025).

CONCLUSIONS

The significantly lower dietary total polyphenol intake of the 35-50 years subgroup compared to the 51-64 years subgroup suggests that the suppressive function of olive oil polyphenol intake on LDL oxidation in Japanese men is influenced by dietary habits and is more clearly demonstrated in the younger age population with a relatively low total polyphenol intake.

Evaluation of Polyphenol Intake in Pregnant Women from South-Eastern Spain and the Effect on Anthropometric Measures at Birth and Gestational Age

During pregnancy, controlling nutrition is crucial for the health of both mother and foetus. While polyphenols have positive health effects, some studies show harmful outcomes during pregnancy. This study evaluated polyphenol intake in a cohort of mother-child pairs and examined its effects on foetal anthropometric parameters. Polyphenol intake was assessed using food frequency questionnaires (FFQs) and 24-h dietary recalls, and analysed with the Phenol-Explorer database. Gestational age and birth measurements were retrieved from medical records. Statistical analyses validated dietary records and assessed polyphenol impact using multivariate generalised linear models. The study found that mean gestational age was 39.6 weeks, with a mean birth weight of 3.33 kg. Mean total polyphenol intake by FFQ was 2231 mg/day, slightly higher than 24-h recall data. Flavonoids and phenolic acids constituted 52% and 37% of intake, respectively, with fruits and legumes as primary sources. This study highlights the use of FFQs to estimate polyphenol intake. Furthermore, the study found associations between polyphenol consumption and anthropometric parameters at birth, with the effects varying depending on the type of polyphenol. However, a more precise evaluation of individual polyphenol intake is necessary to determine whether the effects they produce during pregnancy may be harmful or beneficial for foetal growth.

A scoping review of dietary assessment questionnaires potentially suitable for assessing habitual dietary intake in the National Health and Nutrition Survey, Japan

This scoping review aimed to identify questionnaire-based dietary assessment methods for use in the National Health and Nutrition Survey (NHNS) in Japan. The search was conducted in three databases (PubMed, Web of Science, and Ichushi) to identify questionnaire such as food frequency questionnaire and dietary history questionnaire validated against dietary recalls or food records for the intakes of both food groups and nutrients among Japanese adults. Study quality was assessed based on previously developed criteria. We extracted the questionnaire characteristics and the design and results of the validation studies. We identified 11 questionnaires, with the number of food items ranging from 40 to 196, from 32 articles of good quality. In the validation studies, participants were aged 30-76 years and 90% of the articles used ≥3 d dietary records as reference. The number of nutrients and food groups with a group-level intake difference within 20% against the reference method ranged from 1 to 30 and 1 to 11, respectively. The range of mean correlation coefficients between questionnaire and reference methods were 0.35-0.57 for nutrients and 0.28-0.52 for food groups. When selecting a survey instrument in the NHNS from the 11 existing questionnaires identified in this study, it is important to select one with high group-level comparison and correlation coefficient values on the intended assessment items after scrutinizing the design and results of the validation study. This review may serve as a reference for future studies that explore dietary assessment tools used for assessing dietary intake in specific representative populations.

Polyphenols as novel interventions for depression: exploring the efficacy, mechanisms of action, and implications for future research

Numerous animal and human studies have assessed the relationship between polyphenols and outcomes related to depression. However, no comprehensive synthesis of the main findings has been conducted. The aim of this manuscript was to systematically review the available evidence from animal and human studies on the association and the effects of dietary polyphenols on depression and provide recommendations for future research. We based our review on 163 preclinical animal, 16 observational and 44 intervention articles assessing the relationship between polyphenols and outcomes related to depression. Most animal studies demonstrated that exposure to polyphenols alleviated behaviours reported to be associated with depression. However, human studies are less clear, with some studies reporting and inverse relationship between the intake of some polyphenols, and polyphenol rich foods and depression risk and symptoms, while others reporting no association or effect. Hence, while there has been extensive research conducted in animals and there is some supporting evidence in humans, further human studies are required, particularly in younger and clinical populations.

Prediagnostic plasma polyphenol concentrations and colon cancer risk: The JPHC nested case-control study

BACKGROUND & AIMS

Epidemiological studies that assessed the associations between dietary polyphenol intakes and colon cancer risk have reported largely null results, possibly due to measurement error associated with dietary assessment. We adopted an objective approach by measuring prediagnostic plasma concentrations of 35 polyphenols and assessing associations with colon cancer risk.

METHODS

We conducted a nested-case control study within the Japan Public Health Center-based prospective study (JPHC Study) utilizing plasma samples collected at the time of a five-year follow-up survey between 1995 and 1999. We identified colon cancer cases who developed cancer during the follow-up from the time of blood collection. Controls were matched by age, sex, area code, population size of the area, season of blood collection, year of blood collection, and duration of fasting time before the blood collection. Prediagnostic concentrations of 35 polyphenols from 375 incident colon cancer cases (followed until 2012) and 710 matched controls were measured by tandem mass spectrometry coupled with ultra-high-pressure liquid chromatography. We used multivariable conditional logistic regression models adjusted for established colon cancer risk factors to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

In sexes combined log2-transformed multivariable models, circulating levels of 3,4-dihydroxyphenylpropionic acid (P = 0.02), ferulic acid (P = 0.02), and caffeic acid (P = 0.03) were inversely, and 3-hydroxybenzoic acid (P = 0.03) was positively, associated with colon cancer risk. For men only, circulating levels of 3,4-dihydroxyphenylpropionic acid was inversely, and 3,5-dihydroxyphenylpropionic acid, gallic acid, (+)-epigallocatechin, 3-hydroxybenzoic acid, and epicatechin were positively, associated with colon cancer risk. In women, plasma caffeic acid and ferulic acid concentration were inversely associated with colon cancer risk. However, all these associations were nonsignificant after adjustment for multiple comparisons. The remaining polyphenols were not associated with colon cancer risk.

CONCLUSION

Coffee-derived 3,4-dihydroxyphenylpropionic acid, ferulic acid, and caffeic acid concentrations were inversely associated with colon cancer risk although the association were nonsignificant after adjustment for multiple comparisons. These results support a possible role of coffee polyphenols in preventing colorectal cancer.

Validity of the Food Frequency Questionnaire-Estimated Intakes of Sodium, Potassium, and Sodium-to-Potassium Ratio for Screening at a Point of Absolute Intake among Middle-Aged and Older Japanese Adults

Using Food Frequency Questionnaires (FFQs) to compare dietary references for screening has been in high demand. However, FFQs have been widely used for ranking individuals in a population based on their dietary intake. We determined the validity of sodium (salt equivalent) intake, potassium intake, and sodium-to-potassium (Na/K) ratio obtained using the FFQ for identifying individuals who deviated from the dietary reference intakes (DRIs) measured using multiple 24-h urinary excretion measurements or 12-day weighed food records (WFR). This study included 235 middle-aged subjects. The correlation coefficients (CCs) between the FFQ and WFR estimates were mostly moderate (0.24−0.54); the CCs between the FFQ and 24-h urinary excretion measurements were low or moderate (0.26−0.38). Values of area under the receiver-operating curve (AUC) at the point of DRIs for salt equivalent or potassium were >0.7 with the WFR as the reference standard and 0.60−0.76 with the 24-h urinary excretion as the reference standard. Using both standard measures, the AUC for the Na/K ratio was <0.7. The accuracy of salt equivalent and potassium intake estimation using the FFQ to determine absolute intake point was comparable to that using WFR, allowing for quantified error, but not as good as that of 24-h urinary excretion.