Dietary Polyphenols: What is the Estimated Intake in Population Studies With Adults and Elderly People?

Estimates of dietary intake of polyphenols have been limited to specific samples from certain population groups, and different databases have been used to quantify the levels of these compounds, which makes it difficult to compare results. PURPOSE OF REVIEW: This review collated estimates of polyphenol intake from population studies including adults and elderly from different parts of the world by using a single database: Phenol-Explorer. RECENT FINDINGS: Through seven population-based studies performed in five different countries, it was possible to identify that Brazil was the country with the lowest intake of polyphenols, whereas Poland had the highest dietary intake. The most ingested subclasses of polyphenols in different countries were phenolic acids and flavonoids, and non-alcoholic beverages (coffee, tea, and orange juice) were the foods that most contributed to the intake of polyphenols. Despite the attempt to standardize this study to obtain worldwide intake estimates that could be comparable, gaps were found regarding the assessment of food consumption, standardization to obtain the polyphenol content of foods in Phenol-Explorer, calculation in aglycone equivalents, and caloric adjustment of the estimates. There is a need for more studies on the dietary polyphenols intake of representative samples of populations from different countries to collate more data on the quantities consumed and the main contributing foods.

Polyphenol intake and gastric cancer: A case-control study in the Brazilian Amazon region

BACKGROUND

Polyphenol intake has been associated with a decreased risk of some types of cancer, including gastric cancer (GC). However, few studies address this topic in the Latin American population. In the present study, we evaluated the association between polyphenol intake and the risk of GC in the Brazilian Amazon region.

METHODS

A case-control study was conducted in Belém (Amazon region) from July 2017 to February 2021. A total of 193 GC cases and 194 controls of both sexes, between 18 and 75 years old, were included in the study. Dietary data were collected using a validated food-frequency questionnaire and polyphenol intake identified using the Phenol-Explorer database. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CI), with adjustement for potential confounders.

RESULTS

Cases and controls had similar total polyphenol intake (356.4 mg/1000 kcal/d and 331.1 mg/1000 kcal/d, respectively; p = 0.086). After adjusting for potential confounders, high consumption of flavan-3-ols (highest vs. lowest tertile: OR 0.41, 95% CI 0.18-0.94) and hydroxybenzoic acids (highest vs. lowest tertile: OR 0.24, 95% CI 0.10-0.56) was associated with a decreased risk of GC. The opposite was true regarding the intake of flavones (OR 2.46, 95% IC 1.17-5.18) and other polyphenols (OR 2.54, 95% IC 1.16-5.54). When stratifying according to anatomical topography, we observed that the intake of total flavonoids, flavan-3-ols, and flavanones reduced the risk of cardia GC while that of hydroxybenzoic acids reduced the risk of non-cardia GC. In addition, the intake of flavones and other polyphenols was associated with an increased risk of non-cardia GC. According to histologic subtypes, hydroxybenzoic acid intake was associated with a reduced risk of intestinal-type GC (OR 0.21, 95% IC 0.07-0.64), while flavone consumption was associated with an increased risk of diffuse-type GC (OR 2.59, 95% IC 1.05-6.42).

CONCLUSIONS

Our findings suggest that in the Brazilian Amazon region the high intake of flavan-3-ols and hydroxybenzoic acids is associated with a reduced risk of GC, suggesting a potential beneficial role of these compounds against GC.

Polyphenol intake and mortality: A nationwide cohort study in the adult population of Spain

BACKGROUND AND AIMS

Polyphenols are secondary metabolites present in small quantities in plant-based food and beverages, with antioxidant and anti-inflammatory properties. Main groups of polyphenols include flavonoids, phenolic acids, stilbenes, and lignans, but their association with mortality has barely been examined. We aimed to assess the association between the intake of 23 polyphenol subgroups and all-cause, cardiovascular, and cancer mortality in a representative sample of the Spanish adult population.

METHODS

Population-based cohort study conducted with 12,161 individuals aged 18+ recruited in 2008-2010 and followed-up during a mean of 12.5 years. At baseline, food consumption was obtained with a validated dietary history, and the Phenol-Explorer database was used to estimate polyphenol intake. Associations were examined using Cox regression adjusted for main confounders.

RESULTS

During follow-up, 967 all-cause deaths occurred, 219 were cardiovascular, and 277 cancer. Comparing extreme categories of consumption, hazard ratios (95% CI) of total mortality for subgroups were: dihydroflavonols 0.85 (0.72-1.00; p-trend:0.046); flavonols 0.79 (0.63-0.97; p-trend:0.04); methoxyphenols 0.75 (0.59-0.94; p-trend:0.021); tyrosols 0.80 (0.65-0.98; p-trend:0.044); alkylmethoxyphenols 0.74 (0.59-0.93; p-trend:0.007); hydroxycinnamic acids 0.79 (0.64-0.98; p-trend:0.014); and hydroxyphenilacetic acids 0.82 (0.67-0.99; p-trend:0.064). For cardiovascular mortality, hazard ratios were: methoxyphenols 0.58 (0.38-0.89; p-trend:0.010); alkylmethoxyphenols 0.59 (0.39-0.90; p-trend:0.011); hydroxycinnamic acids 0.63 (0.42-0.94; p-trend:0.020); and hydroxyphenilacetic acids 0.69 (0.48-0.99; p-trend:0.044), when comparing extreme tertiles of consumption. No statistically significant associations were observed for cancer. The main food sources for these polyphenol subgroups were red wine, leafy green vegetables, olive oil, green olives, and coffee (the latter being the major contributor of methoxyphenols, alkylmethoxyphenols, and hydroxycinnamic acids).

CONCLUSIONS

In the Spanish adult population, intake of specific polyphenol subgroups was prospectively associated with a 20% lower all-cause mortality risk. This decrease was mainly due to a 40% lower cardiovascular mortality risk over time.

Dietary intake of total polyphenols and the risk of all-cause and specific-cause mortality in Japanese adults: the Takayama study

Purpose

Several epidemiological studies have demonstrated the health benefits of polyphenols, but the associations between polyphenol intake and mortality including total and major causes of death remain unclear. We investigated the associations between subjects’ total polyphenol intake and their mortality from all causes, cardiovascular disease (CVD), cancer, and other causes of death in a population-based cohort study in Japan.

Methods

A total of 29,079 residents of Takayama City, Japan were analyzed. Their dietary intake was assessed using a validated semi-quantitative food-frequency questionnaire (FFQ) in 1992. Mortality was ascertained over the subsequent 16 years. The dietary polyphenol intake was calculated by matching the subjects’ food consumption data with our original polyphenol content database.

Results

A total of 5339 deaths occurred during the follow-up. After multivariable adjustment, the highest quartile of total polyphenol intake compared with the lowest quartile was significantly associated with a lower risk of all-cause mortality (HR: 0.93, 95% CI: 0.82–0.99, p trend = 0.003). The subjects in the highest quartile showed significantly lower CVD mortality compared to those in the lowest quartile, and among the types of CVD mortality, a strong inverse association was observed for stroke mortality. Inverse associations were also observed for mortality from other causes, specifically digestive disease. The total polyphenol intake was not significantly associated with the risk of cancer mortality.

Conclusions

The results of this prospective study indicate that dietary total polyphenol intake in Japanese is inversely associated with all-cause mortality and mortality from cardiovascular and digestive diseases.

Serum gamma-glutamyltransferase is inversely associated with dietary total and coffee-derived polyphenol intakes in apparently healthy Japanese men

PURPOSE

Serum γ-glutamyltransferase (GGT) has been proposed as a marker of oxidative stress. Here, we examined the association between serum GGT and the dietary intake of polyphenols, which have antioxidant properties.

METHODS

A cross-sectional survey including 7960 apparently healthy Japanese men (aged 22-86 years) who participated in health checkups was conducted in Shizuoka, Japan. We analyzed these subjects' clinical serum parameters and lifestyle factors, including dietary polyphenol intake, which was evaluated by a self-administered questionnaire and by matching the subjects' food consumption data with our original polyphenol content database.

RESULTS

The average intake of polyphenols was 1157 ± 471 mg/day, and green tea was the largest source of polyphenols at 40%, followed by coffee at 36%. Dividing the population according to quintiles of total polyphenol intake, the difference in polyphenol intake from coffee between the groups was much greater than the difference in polyphenol intake from green tea. The analysis of the association between polyphenol intake and biological parameters showed a significant negative association between polyphenol intake and the levels of systolic and diastolic blood pressure (SBP and DBP), GGT, and alanine aminotransferase (ALT) after adjusting for age, smoking habit, energy intake and alcohol intake. The GGT levels were inversely associated with the polyphenol intake from coffee, but not with that from green tea. Multivariable linear regression analyses demonstrated that the subjects' GGT levels were negatively and independently associated with their polyphenol intake.

CONCLUSIONS

The intake of total polyphenol including coffee as a major contributor is inversely associated with the serum GGT concentration in Japanese males.

The effect of coffee intake on lysophosphatidylcholines: A targeted metabolomic approach

BACKGROUND & AIM

Lysophosphatidylcholines (lysoPC) are known to be a pathological component of oxidized-LDL, and several studies demonstrate its pro-inflammatory properties in vitro. Nevertheless, bioactive compounds found in coffee, such as phenolic acids might inhibit LDL oxidation. The relationship between coffee consumption and lysoPC has not been described previously in humans. The aim of the present study was to assess the association between coffee intake and plasma lysoPC levels in adults.

METHODS

Data was from the "Health Survey of Sao Paulo (ISA-Capital)", a cross-sectional population-based survey in Sao Paulo, among 169 individuals aged 20 years or older. This population was categorized into three groups: non-coffee consumers (0 mL/day-G1), low coffee consumers (≤100 mL/day-G2), and high coffee consumers (>100 mL/day-G3). Usual coffee intake was estimated by two 24HR and one FFQ, using Multiple Source Method. Quantification of the metabolites was performed by mass spectrometry (FIA-MS/MS and HPLC-MS/MS) and 14 lysoPC species were identified. The association between coffee intake and lysoPC was analyzed by multiple linear regression adjusted for age, sex, household per capita income, smoking, physical activity, body mass index, total energy intake, use of drugs, vegetables and fruit consumption and caffeine intake.

RESULTS

LysoPC levels were significantly lower in G3 than in G1, for the lysoPC a C16:1 (β = -0.56; p = 0.014), lysoPC a C18:1 (β = -2.57; p = 0.018), and lysoPC a C20:4 (β = -1.14; p = 0.037). In opposition, the ratios of C16:0/C16:1 and C18:0/18:1 was higher in G3 (β = 5.04; p = 0.025 and β = 0.28; p = 0.003, respectively).

CONCLUSION

LysoPC profile differed according to coffee intake, showing a possible beneficial health effect of this beverage on inflammatory and oxidative processes.