Nutritional Biomarkers Show Higher Flavan‑3‑ol Intake is Associated with Lower Blood Pressure

by | Nov 24, 2020 | 2020, Blood Pressure, Cardiovascular Health, Flavonoids

Written by Joyce Smith, BS. This study investigated associations between biomarker-estimated flavanol intake and blood pressure and other cardiovascular disease risk markers.

blood pressureHigh blood pressure is a leading disease risk factor globally, and cardiovascular disease (CVD) is a global leading cause of death 1, Changes in dietary habits have an important role to play in the prevention of CVD. Most of today’s dietary recommendations have focused on dietary patterns and macronutrients 2, but increased attention is now being focused on a group of non-nutritive dietary compounds, or bioactives, which are thought to affect our physiology and impact our risk for disease 3. Flavanols are a major class of dietary bioactives 4, and belong to a group of polyphenolic compounds called flavonoids. They include catechin, epicatechin, epigallocatechin, epicatechin gallate and epigallocatechin gallate and are found in teas, cocoa-derived products, fava beans, red wine, nuts, and many fruits, particularly in the skins of grapes, apples, and blueberries.  Intervention studies have shown that flavan-3-ols improve vascular function 4,5; and, while these flavanols are valuable when developing dietary recommendations for cardiovascular disease prevention, their content in foods varies considerably 6, thus determining actual dietary flavanol intake is very difficult without the use of nutritional biomarkers. These biomarkers can be assessed by measuring the presence of dietary compounds or their metabolites in the body and enable researchers to objectively and accurately estimate a person’s actual flavanol intake 7.

The following study by Ottaviani and team 8 examined potential cross-sectional associations between biomarker-estimated flavan-3-ol intake and blood pressure as well as other cardiovascular disease risk markers among 25,618 participants, 40 to 75 years of age, from the European Prospective Investigation into Cancer Norfolk study. Fifty-five percent (14,026) of participants were women; median follow up was 19.5 years; diet was assessed via a 7-day diary. Two different biomarkers were used to estimate flavan-3-ol intake, one based on the flavan-3-ol-derived microbial metabolite gVLMB, the other based on the structurally related (–)-epicatechin metabolites (SREM). Using urine measures of these surrogate biomarkers 9 researchers were able to specifically assess the dietary intake of flavan-3-ols in this large population and their association with blood pressure. Secondary objectives were to investigate associations with cardiovascular disease risk. Multivariable regression analysis was used to investigate associations between biomarker-estimated flavan-3-ol intake and different food groups, Analysis also adjusted for the following confounders: age, BMI, social class and energy intake, and was stratified by sex.

High flavan-3-ol intake was associated with significantly lower systolic and diastolic blood pressure and inversely associated with blood lipids. The difference in blood pressure between those with the lowest 10% of flavanol intake and highest 10% was between 2 and 4 mmHg which is similar to the changes seen with a Mediterranean diet in the PREMIMED trial or a moderate salt reduction as in the Dietary Approaches to Stop Hypertension (DASH) diet. A subgroup analysis confirmed a strongest association for those with highest risk of cardiovascular disease, particularly for those with existing hypertension. Correlation between biomarker-estimated flavan-3-ol and self-reported food diaries was weak or non-existent due to the high variability of flavan-3-ol in food.

A study strength was the use of nutritional biomarkers that, unlike self-reported dietary data, addressed the great variability in food composition, thereby, lending credence to the inverse association found between flavanol intake and blood pressure. In light of today’s aging population with its increasing prevalence of chronic disease, these study results validate the health benefits of dietary flavanols particularly with respect to cardiovascular disease prevention and confirms the results from previous dietary intervention studies such as the Mediterranean and DASH diets by affirming that a habitual diet rich in flavanols can also improve blood pressure and decrease cardiovascular disease risk.

Source: Ottaviani, Javier I., Abigail Britten, Debora Lucarelli, Robert Luben, Angela A. Mulligan, Marleen A. Lentjes, Reedmond Fong et al. “Biomarker-estimated flavan-3-ol intake is associated with lower blood pressure in cross-sectional analysis in EPIC Norfolk.” Scientific reports 10, no. 1 (2020): 1-14.

© The Author(s) 2020. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, http://creativecommons.org/licenses/by/4.0/.

Click here to read the full text study.

Posted November 24, 2020.

Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from  the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.

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