Polyphenol epidemiology: looking back and moving forward

[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.

Protective Effects of Foods Containing Flavonoids on Age-Related Cognitive Decline

PURPOSE OF REVIEW

Evidence suggests that flavonoids, polyphenolic compounds found in many plant-derived foods, such as berries, may allay cognitive impairment. We review recent research exploring the protective effects of flavonoids on age-related cognitive decline and neurodegenerative disorders in humans and animals. We also address the mechanisms by which flavonoids may exert their effects and promising avenues of future research.

RECENT FINDINGS

Flavonoids have been found to decrease neuroinflammation, reduce oxidative stress, and mediate neuroplasticity in animal models of neurodegeneration and aging. Injecting flavonoids encased in metal nanoparticles may further enhance the efficacy of flavonoids. Animal studies also demonstrate that flavonoid supplementation may alleviate neurodegenerative cognitive and memory impairments. Limited human studies, however, demonstrate the need for further clinical research investigating flavonoids. Flavonoid supplementation, as well as dietary modification to include whole foods high in flavonoids, may provide therapeutic potential for aging individuals experiencing cognitive deficits resulting from neurodegeneration.

Prospective Association between Total and Specific Dietary Polyphenol Intakes and Cardiovascular Disease Risk in the Nutrinet-Santé French Cohort

BACKGROUND

Epidemiological and experimental evidence support a protective effect of dietary polyphenols on chronic diseases, but high quality longitudinal data are needed, including details on categories of polyphenols. Our objective was to investigate the prospective association between total and individual classes and subclasses of dietary polyphenols and the risk of major cardiovascular disease in the NutriNet-Santé cohort.

METHODS

A total of 84,158 participants, who completed at least three 24 h dietary records, were included between May 2009 and June 2017. Individual polyphenols intakes were obtained by matching food consumption data from the 24 h dietary records with the Phenol-Explorer polyphenol composition database. Multivariable Cox proportional hazards models were used to characterize the associations between dietary polyphenols and the incidence of cardiovascular diseases, comparing tertile T3 vs. T1 of classes and subclasses of polyphenols.

RESULTS

Over a median of 4.9 years of follow-up, 602 major cardiovascular events were diagnosed. Intakes of anthocyanins, catechins, and flavonols were strongly inversely associated with cardiovascular disease risk (anthocyanins: Hazard Ratio (HR)for a 1-point increment of 10 mg/day = 0.98 (0.96⁻0.99, p = 0.03, HRT3vs.T1 = 0.66 (0.52⁻0.83), ptrend = 0.0003; catechins: HRfor a 1-point increment of 10 mg/day = 0.98 (0.96⁻0.99), p = 0.02, HRT3vs.T1 = 0.74 (0.60⁻0.91), ptrend = 0.004; flavonols: HRfor a 1-point increment of 10 mg/day = 0.94 (0.90⁻0.99), p = 0.02, HRT3vs.T1 = 0.75 (0.61⁻0.94), ptrend = 0.006). Intakes of dihydrochalcones, proanthocyaninidins, dihydroflavonols, hydroxybenzoic acids, and stilbenes were also associated with a decrease (13%, 19%, 24%, 24%, and 27%, respectively) in cardiovascular disease risk, when comparing tertile T3 to T1.

CONCLUSIONS

Higher intakes of polyphenols, especially of anthocyanins, catechins, and flavonols, were associated with a statistically significant decreased cardiovascular disease risk.

Compliance with Nutritional and Lifestyle Recommendations in 13,000 Patients with a Cardiometabolic Disease from the Nutrinet-Santé Study

BACKGROUND

A healthy diet has been shown to prevent cardiovascular diseases complications. The objective of this study was to assess dietary intakes and compliance with nutritional and lifestyle recommendations in French adults diagnosed with hypertension, diabetes, dyslipidaemia or cardiovascular disease compared with healthy individuals.

METHODS

Data was collected from 26,570 subjects aged 35 to 70 years (13,285 patients and 13,285 controls matched by sex and age) of the French cohort NutriNet-Santé. Dietary intakes were assessed using three 24-h records. Mean food and nutrient intakes of patients were compared to those of healthy subjects using multivariable mixed logistic and linear regressions.

RESULTS

Compared to healthy controls, adults reporting cardiometabolic diseases had lower intakes of sweetened products, higher intakes of fish and seafood and a better compliance with dairy products. However, overall, they reported unhealthier lifestyles and dietary habits. Indeed, they were less often physically active and had similar habits regarding alcohol and tobacco consumption. They also had lower intakes of fruit, higher intakes of meat, processed meat and added fats. It is noteworthy that diabetic subjects tended to show the highest compliance with certain dietary recommendations (vegetables, pulses and whole grain products).

CONCLUSION

Our study brings into focus the fact that some nutritional aspects still need to be improved among individuals with a cardiometabolic disease. We should encourage higher intakes of fruits and vegetables, whole grain products, and lower intakes of meat and sodium, as well as healthy lifestyle (physical activity, no-smoking and limited intake of alcohol) in order to encourage a healthier management after being diagnosed.