Yerba Mate (Ilex Paraguariensis A.St.-Hil.): Assessment of Cardiovascular Health

Mate or yerba-mate (Ilex paraguariensis A.St.-Hil.) is a native plant from South America highly consumed in this region. Different traditional products (mate, mate tea, chimarrao, tereré) are obtained from the yerba-mate leaves and consumed as herbal tea. Mate is a rich source of bioactive phenolic compounds, mainly caffeoylquinic acids. The richness of different mono- and dicaffeoylquinic acids is a peculiarity of mate derived products. However, in contrast to other plant-based beverages rich in polyphenols like tea or coffee, the research and the industry have yet little explored the potential interest of mate product to promote human health. There has been a growing interest to the development of healthier foods to face the burden of cardiovascular diseases (CVD), especially those naturally rich in bioactive phenolic compounds with protective effects against the development of chronic diseases. Different in vitro and animals studies associate the mate consumption with cardiovascular protection mechanisms. Consistent information about this activity and the long-term consumption effects in humans are scarce. The aim of this study is to assess through a randomized controlled trial the impact of chronic intake of mate on intermediate biomarkers of cardiovascular health in humans and to identify possible involved nutrigenomic mechanisms.

Mate is a traditional drink obtained from the leaves of yerba-mate (Ilex paraguariensis A.St.-Hil.), a native species of South America that has a great regional importance. Mate is highly consumed in South America countries because of the tradition acquired from the native populations. In these countries, mate is consumed as largely as tea (camellia sinensis) in Asia and Europe and coffee in Europe and North America. Mate constitutes a raw material little explored compared to other plant products like coffee or tea. However, mate product has recently raised interest due to both its high content of phytochemicals and the peculiarity of its phenolic profile, characterized by the wealth in mono and dicaffeoylquinic acids, known for their biological activities.

A large number of in vitro studies have evaluated the antioxidant capacity of mate products with different methodologies, and showed that the antioxidant effect was related to the presence of caffeoyl derivatives. Mate appears as a potent inhibitor of low-density lipoproteins (LDL) oxidation. The phenolic compounds of mate also exhibit free radical scavenging properties and inhibit a chemically induced oxidation of lipid in membranes. Different animal studies have reported a positive impact of mate consumption on some cardiovascular risk factors. These published data, obtained in different rodent models of diet induced dyslipidemia, obesity or atherosclerosis, suggest that the supplementation with mate products may improve plasma lipids profile, prevent hepatic fatty deposition, reduce insulin resistance, improve endothelial function and inhibit atherosclerosis progression. Few clinical studies reported positive effects of mate consumption on the blood lipid profile, glycemia and anthropometric parameters in healthy and unhealthy subjects.

The aim of this study is to assess through a randomized controlled trial the impact of chronic intake of mate on intermediate biomarkers of cardiovascular health in humans and to identify possible nutrigenomic mechanisms involved.

The study consists in a controlled, randomized, double blind, crossover clinical trial. This study will involve 36 healthy middle-age (45-65) male subjects selected according to the inclusion and exclusion criteria previously established. The study will have a maximum duration of 84 days including the wash-out period. The volunteers will have to consume daily for 4 weeks the mate extract (with a standardized content in phenolic compounds) or the placebo. At the beginning and/or at the end of each experimental period, blood will be sampled for measurement of glycemic and lipidic parameters, inflammatory markers and transcriptome analysis. Urine samples will also be collected for metabolomics analysis to characterize the exposure profile of volunteers in response to mate phenolic compounds consumption.

Eligibility Criteria:
Inclusion Criteria:

* No smoking, or having stopped smoking for more than three years;
* Having no more than one of the five criteria associated with metabolic syndrome proposed by the National Cholesterol Education Program's Adult Treatment Panel III (NCEP-ATP III) and approved by Brazilian scientific societies in the First Brazilian Guideline for Diagnosis and Treatment of Metabolic Syndrome (2005);
* Not consuming multivitamin supplements, antioxidants or polyphenols rich products in the last 3 months before the study;
* Accepting reduced consumption of natural polyphenols rich beverages (yerba mate, tea, coffee, wine, cocoa, soy milk, fruit juices) during the study;
* Not using any antihypertensive or anticholesterolemic drugs;
* Accepting to participate in the study after signing the Informed Consent and completing the information document.

Exclusion Criteria:

* Being diagnosed with diabetes, mental illness or other severe conditions that may influence the results of the study;
* Chronic alcoholism;
* Having severe hypertension with clinical complications such as acute myocardial infarction and other coronary artery diseases;
* Having kidney or liver diseases;
* Not accepting to participate in the study refusing to sign the Informed Consent, in accordance with the fundamental ethical and scientific requirements.