Despite consistent evidence that greater consumption of fruits and vegetables (FV) is associated with significant reductions in chronic disease morbidity and mortality, the majority of adults in the United States consume less than the amounts recommended by public health agencies. As such, there is a critical need to design and implement effective programs and policies to facilitate increases in FV consumption for the prevention of these diseases. To accomplish this, an accurate, inexpensive, and convenient method for estimating the dietary FV intake is required. A promising method for quantifying the FV intake via proxy that has gained interest in recent years is the measurement of skin carotenoid levels via spectroscopy-based devices. However, there exist certain dietary and non-dietary factors that may affect the skin carotenoid levels independently of the dietary intake of carotenoids. In order to validate the ability of this method to accurately estimate the FV intake among diverse demographics, these factors must be identified and taken into consideration. Therefore, this narrative review seeks to summarize the available research on factors that may affect the skin carotenoid levels, determine current gaps in knowledge, and provide guidance for future research efforts seeking to validate spectroscopy-measured skin carotenoid levels as a means of accurately estimating the FV intake among various populations.

This study aimed to identify the association between the risk of hyper-LDL cholesterolemia (hyper-LDLC) and fatty acid consumption patterns (FACPs) using the data from the Korean Genome and Epidemiology Study (KoGES) prospective cohort. A total of 6542 middle-aged Korean adults were included in the analysis. Four FACPs were identified through principal component analysis of the reported intakes of 34 fatty acids (FAs): “long-chain FA pattern”; “short & medium-chain saturated fatty acid (SFA) pattern”; “n-3 polyunsaturated fatty acid (PUFA) pattern”; and “long-chain SFA pattern”. The “long-chain SFA pattern” lowered the risk of hyper-LDLC (relative risk (RR), 0.82; 95% confidence interval (CI), 0.72–0.94; p for trend, 0.004) and the “short & medium-chain SFA pattern” increased the risk of hyper-LDLC (RR, 1.17; 95% CI, 1.03–1.32; p for trend = 0.004). In sex-stratified analyses, the associations of the “long-chain SFA pattern” (RR, 0.73; 95% CI, 0.58–0.93; p for trend = 0.007) and the “short & medium-chain SFA pattern” (RR, 1.34; 95% CI, 1.07–1.69; p for trend = 0.003) with the hyper-LDLC risk were observed only in men, but not in women. These results suggest that FACPs with a high intake of long-chain SFA or a low intake of short and medium-chain SFA may protect Korean adults from hyper-LDLC.

Increasing global kimchi consumption has prompted interest in its health impact. However, comprehensive reviews of the influence of kimchi on cardiometabolic risk factors, especially meta-analyses, remain limited. This review assessed the impact of fermented kimchi consumption on cardiometabolic risk factors by systematically reviewing human intervention and prospective cohort studies, and conducting a meta-analysis of intervention studies. A literature search of PubMed, EMBASE, Scopus, Web of Science, RISS, KISS, and ScienceON databases was conducted through April 30, 2024. The inclusion criteria encompassed studies that examined the effects of fermented kimchi, without any added ingredients or lactic acid bacteria, on health outcomes, including anthropometric measures, blood pressure, cardiometabolic and glycemic indicators, inflammatory cytokines, and the incidence of related chronic diseases. Data extraction and quality evaluation were conducted independently by 3 researchers. Pooled effect sizes were calculated as weighted mean differences (WMDs) with 95% CIs employing random-effects models. Five intervention studies (205 participants) and 4 prospective cohort studies (42 455 participants) were selected. A meta-analysis of the intervention studies revealed a significant reduction in fasting blood glucose (WMD: −1.93 mg/dL; 95% CI: −3.82, −0.03; I² = 17.4%) following the consumption of fermented kimchi. After excluding studies that contributed to increased heterogeneity, significant inverse associations were observed between fermented kimchi consumption and triglycerides (WMD: −28.9 mg/dL; 95% CI: −53.2, −4.5; I² = 0.0%), systolic blood pressure (WMD: −3.48 mmHg; 95% CI: −5.95, −1.01, I² = 0.0%), and diastolic blood pressure (WMD: −2.68 mmHg; 95% CI: −4.75, −0.62; I² = 0.0%). Prospective cohort studies linked higher kimchi intake with a lower incidence of cancer and metabolic syndrome and an increased likelihood of achieving normal body weight. This review supports beneficial effects of fermented kimchi on cardiometabolic health. However, due to the limited number of studies, these findings should be interpreted cautiously, highlighting the need for further research in diverse populations. PROSPERO registration No. CRD42024532020.

The aim of this study was to examine the independent association between flavonoid intake and hypo-high-density lipoprotein (HDL)-cholesterolemia and the potential modifying effect of polyunsaturated fatty acid (PUFA) intake on this association among Korean adults. This cross-sectional analysis used data from 10,326 subjects who participated in the 2013–2016 Korean National Health and Nutrition Examination Survey. Multiple logistic regression analyses were used to assess the associations of flavonoid and PUFA intakes with hypo-HDL-cholesterolemia prevalence. Proanthocyanidins intake showed an inverse relationship with hypo-HDL-cholesterolemia only in men (Tertile (T) 3 vs. T1: odds ratio (OR) = 0.74, 95% confidence interval (CI) = 0.59–0.92, p-trend = 0.0330). Total flavonoid and PUFA intakes were not associated with hypo-HDL-cholesterolemia in both men and women. However, when stratified by PUFA intake, there was an inverse relationship between total flavonoid intake and hypo-HDL-cholesterolemia prevalence in men with a high n-3 PUFA intake (total flavonoid intakes T3 vs. T1: OR = 0.59, 95% CI = 0.42–0.82, p-trend = 0.0004) or a low n-6/n-3 PUFA intake ratio (T3 vs. T1: OR = 0.67, 95% CI = 0.48–0.93, p-trend = 0.0053), but not in those with a low n-3 PUFA intake (p-interaction = 0.0038) or a high n-6/n-3 PUFA intake ratio (p-interaction = 0.1772). In women, no association was found between total flavonoid intake and hypo-HDL-cholesterolemia, regardless of PUFA intake. These results imply that the intake of proanthocyanidins might have beneficial effects on the HDL-cholesterol level in Korean men. In addition, n-3 PUFA intake might modify the association of total flavonoid intake with the hypo-HDL-cholesterolemia among Korean men.

Blood carotenoid concentration measurement is considered the gold standard for fruit and vegetable (F&V) intake estimation; however, this method is invasive and expensive. Recently, skin carotenoid status (SCS) measured by optical sensors has been evaluated as a promising parameter for F&V intake estimation. In this cross-sectional study, we aimed to validate the utility of resonance Raman spectroscopy (RRS)-assessed SCS as a biomarker of F&V intake in Korean adults. We used data from 108 participants aged 20–69 years who completed SCS measurements, blood collection and 3-d dietary recordings. Serum carotenoid concentrations were quantified using HPLC, and dietary carotenoid and F&V intakes were estimated via 3-d dietary records using a carotenoid database for common Korean foods. The correlations of the SCS with serum carotenoid concentrations, dietary carotenoid intake and F&V intake were examined to assess SCS validity. SCS was positively correlated with total serum carotenoid concentration (r = 0·52, 95 % CI = 0·36, 0·64, P < 0·001), serum β-carotene concentration (r = 0·60, 95 % CI = 0·47, 0·71, P < 0·001), total carotenoid intake (r = 0·20, 95 % CI = 0·01, 0·37, P = 0·04), β-carotene intake (r = 0·30, 95 % CI = 0·11, 0·46, P = 0·002) and F&V intake (r = 0·40, 95 % CI = 0·23, 0·55, P < 0·001). These results suggest that SCS can be a valid biomarker of F&V intake in Korean adults.

The increasing prevalence of obesity is a serious concern in Korea. However, there is currently no available food-frequency questionnaire (FFQ) for examining the dietary patterns of adults with obesity. This study aimed to develop a semi-quantitative FFQ tailored to Korean adults with obesity. The dish/food items for the FFQ were extracted from the 24 h recall data of 8450 Korean adults (aged 19–64 years) with obesity who participated in the 2013–2019 Korea National Health and Nutrition Examination Survey. Among the 1709 dishes consumed, 475 were selected based on their high contribution to the intake or substantial between-individual variation in 11 nutrients: energy, carbohydrates, dietary fiber, sugar, fat, saturated fat, protein, sodium, vitamin A, vitamin E, and flavonoids. These dishes were subsequently categorized into 129 items based on their recipes and primary ingredients. The final 129 items included rice; noodles and dumplings; breads, rice cakes, and cereals; soups and stews; eggs, pulses, meat, and fish; vegetables and kimchi; fruit; snacks; beverages; milk/dairy products; alcohol; and water. The response options for intake frequency comprised nine options, and the intake amount response included three options (50%, 100%, and 150–200% of the standard intake). After validation, this FFQ is expected to be used in epidemiological studies to investigate the dietary patterns of Korean adults with obesity.