Research

You are here

University of Reading

1. Overview

Mars has a long-term partnership with the University of Reading that covers research in many areas of the university’s expertise, including agriculture, plant sciences and nutrition. For many years, we have conducted research into flavanols together. We were both part of the pan-European research consortium FLAVIOLA, whose six other partners included Heinrich Heine University Düsseldorf. FLAVIOLA was an EU-funded project that aimed to improve understanding of dietary flavanols. Today, Mars and the University of Reading continue to study cocoa flavanols, focusing on analytics, dietary intervention trials and epidemiological studies.

2. Partnership outcomes

Below are some recent outcomes from research conducted by Mars and the University of Reading.

Dietary intake of flavanols in the EU

Several studies have shown that flavanol intake can improve blood vessel function, blood pressure and cholesterol. A team of researchers from Mars, the University of Reading, the University of Cambridge and Heinrich Heine University Düsseldorf conducted a study that was published in the British Journal of Nutrition in 2014 whose aim was to understand how much of these beneficial compounds people in the European Union were consuming on a daily basis. Using the EFSA Comprehensive European Food Consumption Database and a recently developed flavanol food composition database, we managed to establish average intake amounts across fourteen EU countries. Overall, mean habitual intake of flavanols was 369 mg/d. However, intake varied considerably. In Ireland, the mean habitual intake was 793 mg/d while, in Czechia, it was only 181 mg/d. We found that tea was the largest source of dietary flavanols in the EU, accounting for 62% of flavanol intake. Pome fruits (e.g., apples and pears), berries, cocoa products and stone fruits were also notable sources of dietary flavanols. The intake of flavanol monomers and theaflavins was particularly high in the British Isles and Central Europe, where consuming tea is common. Intake of proanthocyanidins, on the other hand, was highest in Spain, Italy and France due to a large amount of fruit in the diet.

At 368 mg/d, the mean habitual intake of dietary flavanols is well below the amount used in various dietary intervention studies that have shown improved blood vessel function and cardiovascular risk after flavanol consumption. It is therefore possible that residents in EU countries are not consuming adequate amounts of flavanols to exploit the full cardioprotective benefit of these compounds. Thanks to this study, scientists are in a better position to investigate the impact of different flavanol intake amounts on public health.

Image: Heat maps showing mean habitual intake of total flavanols, flavanol monomers, proanthocyanidins and theaflavins in 14 countries across the EU. The consumption of total flavanols, flavanol monomers and theaflavins is higher in the British Isles and central Europe, where the consumption of tea is common. In southern Europe, the intake of proanthocyanidins is higher due to the consumption of fruit, in particular pome fruit.

Read more about this study: Vogiatzoglou, A., et al., Assessment of the dietary intake of total flavan-3-ols, monomeric flavan-3-ols, proanthocyanidins and theaflavins in the European Union. Br J Nutr, 2014

Prospective cohort study indicates flavanol intake not sufficient to reduce CVD risk

A team from Mars, Incorporated, the University of Reading, the University of Cambridge and Heinrich Heine University Düsseldorf conducted an investigation into the association between flavanol consumption and cardiovascular disease risk, which was published in the journal Free Radical Biology and Medicine in 2015. The research team had access to detailed dietary information from almost 25,000 participants from the EPIC-Norfolk cohort who had completed a 7-day food diary. The study found no association between flavanol intake and blood pressure and cardiovascular disease risk. This result is corroborated by earlier epidemiological studies, however it contradicts the findings of dietary intervention studies, which have shown previously that individuals consuming a diet high in flavanols see improvements in vascular function measures (which are markers of cardiovascular disease risk) when compared to placebo controls. The reason for this discrepancy could lie in the types of flavanols being consumed by the EPIC-Norfolk cohort. Using food composition tables, we estimated that only 10% of the EPIC-Norfolk population were consuming more than 50 mg/d of (−)-epicatechin, which is the threshold beyond which improvements in blood pressure have been observed in the past. The flavanol (−)-epicatechin is also the only member of the flavanol group to have been directly and causally linked to improvements in blood vessel function.

Prospective cohort study indicates flavanol intake not sufficient to reduce CVD risk

A team from Mars, Incorporated, the University of Reading, the University of Cambridge and Heinrich Heine University Düsseldorf conducted an investigation into the association between flavanol consumption and cardiovascular disease risk, which was published in the journal Free Radical Biology and Medicine in 2015. The research team had access to detailed dietary information from almost 25,000 participants from the EPIC-Norfolk cohort who had completed a 7-day food diary. The study found no association between flavanol intake and blood pressure and cardiovascular disease risk. This result is corroborated by earlier epidemiological studies, however it contradicts the findings of dietary intervention studies, which have shown previously that individuals consuming a diet high in flavanols see improvements in vascular function measures (which are markers of cardiovascular disease risk) when compared to placebo controls. The reason for this discrepancy could lie in the types of flavanols being consumed by the EPIC-Norfolk cohort. Using food composition tables, we estimated that only 10% of the EPIC-Norfolk population were consuming more than 50 mg/d of (−)-epicatechin, which is the threshold beyond which improvements in blood pressure have been observed in the past. The flavanol (−)-epicatechin is also the only member of the flavanol group to have been directly and causally linked to improvements in blood vessel function.

Read more: Vogiatzoglou, A., et al., Associations between flavan-3-ol intake and CVD risk in the Norfolk cohort of the European Prospective Investigation into Cancer (EPIC-Norfolk). Free Radic Biol Med, 2015

Age has little impact on the absorption, distribution, metabolism and excretion of cocoa flavanols

A paper published in the journal Molecular Nutrition & Food Research in 2015 by researchers from Mars, the University of Reading and Heinrich Heine University Düsseldorf showed that there are only small differences in the way cocoa flavanols are absorbed, metabolized and excreted by young people and old people. The group of younger people in the study (aged 18-35) and the group of older people (aged 65-80) consumed two cocoa-flavanol-containing drinks in this placebo-controlled crossover study, one drink had a cocoa-flavanol concentration of 5.3 mg/kg body weight and the other with a concentration of 10.7 mg/kg body weight. At the low concentration, there were no significant differences in absorption, metabolism and excretion between young and old. At the higher concentration, there was a small but significant difference in the concentration of certain metabolites in the blood and urine. Since there are few differences in the way cocoa flavanols and cocoa-flavanol metabolites are behaving inside the body between young and old, it is expected that the beneficial effect of these compounds on vascular function will translate between different age groups. These results also support the potential of developing dietary guidelines for flavanols in the long term.

Read more about this study: Rodriguez-Mateos, A., et al., Influence of age on the absorption, metabolism, and excretion of cocoa flavanols in healthy subjects. Mol Nutr Food Res, 2015

A pharmacokinetic profile for (−)-epicatechin

In 2016, scientists from Mars, the University of California, Davis and the University of Reading in the UK published research in Nature Scientific Reports that established a pharmacokinetic profile for the flavanol compound found in cocoa called (−)-epicatechin. The compound is one of the most commonly consumed flavanols and is found naturally in tea, apples, pears, grapes, various berries and fresh cocoa beans.

We found that when the participants in the study were consuming (−)-epicatechin, none of it ended up in the blood. Instead, it was all metabolized inside the body into a series of over 20 different structurally related compounds. By measuring how long it took for these metabolites to appear in the bloodstream, we were also able to establish that much of this metabolism depended on processes specific to the bacteria in the gut.

Dietary intake of the compound (−)-epicatechin has been shown to improve the function of the blood vessels. The important outcome from this study, though, is that these improvements must be mediated by the 20+ metabolites that are absorbed into the bloodstream rather than by (−)-epicatechin itself. What is more, none of these metabolites act as anti-oxidants inside the body. We believe that any future in vitro cell-culture studies looking at the effects of (−)-epicatechin and other flavanols on the body should take into account how these compounds are metabolized by the body.

Image: The flavanol compounds found in the plants that we eat were shown in this study to be different to the compounds that enter the bloodstream. The compound (−)-epicatechin in metabolized into 20+ structurally related compounds that are then absorbed into the blood.

Another important finding in this study was that humans metabolized (−)-epicatechin differently to rats and mice. This is important because rodent models are often used to test the safety of specific compounds for human consumption. For the first time, we showed that rodents are not equivalent to humans in the metabolism of (−)-epicatechin — which could be the case for other polyphenolic compounds, as well.

Read more about this study: Ottaviani, J.I., et al., The metabolome of [2-(14)C](−)-epicatechin in humans: implications for the assessment of efficacy, safety, and mechanisms of action of polyphenolic bioactives. Sci Reports 2016

Gamma-valerolactone a reliable biomarker of flavanol intake

Another recent outcome from the relationship came from a study conducted by a team from Mars, the University of California, Davis, the University of Reading and the University of Cambridge in the UK. We managed to identify a nutritional biomarker that can be used to assess intake of flavan-3-ols, a type of commonly consumed flavanol found in food. A nutritional biomarker is, roughly speaking, a sort of test that scientists or medical professionals can perform to get an idea of what is going on inside the body. The biomarker discovered in this project is a compound present in the urine called gamma-valerolactone (gVL). Gamma-valerolactone only appears in the urine after people have consumed food or drink containing certain flavan-3-ols, including (−)-epicatechin. Using a urine test, scientists will now be able to assess whether people are consuming a diet high or low in these flavanols. They can use that information in scientific studies to determine whether the amount of flavanols in the diet affects study endpoints, such as the risk of developing cardiovascular disease. Previously, scientists would have to ask study participants to complete a food diary to determine the amount of flavanols in their diet, which can be unreliable.

Importantly, using urinary gamma-valerolactone concentration as a nutritional biomarker meets the criteria laid down by the International Agency for Research on Cancer (IARC) and the Institute of Medicine (IOM) for nutritional biomarkers. As part of the study, we found that the biomarker is specific for flavan-3-ols present in tea, fruits, wine and cocoa-derived products. There is no formation of gVL with other flavonoids or polyphenols. There is also a consistent relationship between the amount of flavan-3-ols consumed in the diet and the amount of gVL in the urine.

Image: Gamma-valerolactone is only formed when people consume certain flavan-3-ols, such as epicatechin gallate (ECG) and the epicatechin monomer (−)-epicatechin. Other polyphenolic compounds such as thearubigins do not result in gVL formation. This makes urinary gVL concentration a biomarker specific to the consumption of certain flavanol compounds.

Read more about this study: Ottaviani, J.I., et al., Evaluation at scale of microbiome-derived metabolites as biomarker of flavan-3-ol intake in epidemiological studies. Sci Reports 2018