Re: Yerba Maté Intake Enhances Fat Metabolism during Light to Moderate Exercise

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	Laura Bystrom, PhD Mariann Garner-Wizard Shari Henson Amy Keller, PhD Cheryl McCutchan, PhD Heather S Oliff, PhD
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PDF (Download)	Yerba Maté (Ilex paraguariensis, Aquifoliaceae) Fat Metabolism Exercise
Date: 04-15-2015	HC# 111412-518

Re: Yerba Maté Intake Enhances Fat Metabolism during Light to Moderate Exercise

Alkhatib A. Yerba maté (Illex [sic] paraguariensis) ingestion augments fat oxidation and energy expenditure during exercise at various submaximal intensities. Nutr Metab (Lond). 2014;11:42. doi: 10.1186/1743-7075-11-42.

Many South Americans consume yerba maté (Ilex paraguariensis, Aquifoliaceae) leaves and stems in the form of a hot tea beverage (an aqueous extract). Several animal studies have indicated that yerba maté may increase energy metabolism and have weight loss effects. Moreover, the authors suggest these effects may be enhanced during moderate exercise. The aim of this double-blind, crossover, repeated-measures study was to assess if yerba maté ingestion increases fatty acid oxidation (FAO) and enhances energy expenditure derived from FAO (EE_FAO) during exercise.

A total of 14 healthy adults (7 men and 7 women) with a mean age of 20.8 ± 3.4 yrs and mean body mass index (BMI) of 23.8 ± 0.11 kg/m² participated in the study (location undisclosed). All subjects were screened and had to meet the following exclusion criteria: free from any disease and no family history of heart disease, high blood pressure, or stroke; not pregnant or breastfeeding; and did not consume more than 200 mg/day of caffeine (from all sources) regularly. All subjects refrained from taking any medication or supplements during the study and did not consume any alcohol or caffeinated beverages or exercise strenuously within 24 hours of each testing period. Subjects completed 24-hour food diaries and a 10-hour overnight fast before each visit to the physiology laboratory (2 visits at least 3 days apart).

At each visit, anthropometric data were collected and each subject either consumed 1000 mg (2x 500 mg capsules with 1.5% caffeine) yerba maté (Rio Trading Company; Brighton, United Kingdom) or a placebo (empty capsules) with 100 ml of water. Subjects rested for 60 minutes after consuming the capsules, during which cardiorespiratory measurements were obtained (oxygen uptake [VO₂], carbon dioxide production [VCO₂], and respiratory exchange ratio [RER]). The exercise protocol consisted of cycling for 3-minute incremental stages that increased by 0.5 W/kg^-1 of body weight. Subjects cycled at 60-70 rpm until exhaustion, which was defined as having 2 out of 3 of the following: RER value > 1.1, heart rate within 10 beats/min of age-predicted maximum heart rate, or achieving leveling off of VO₂.

In addition, capillary blood samples were obtained from finger pricks when the subjects were at rest, during the last 30 seconds of each incremental cycling stage, and 1, 3, and 5 minutes after subjects reached exhaustion. Blood samples were analyzed for blood lactate concentration (BLC), an indicator of exercise fatigue. FAO and carbohydrate oxidation (CHO) were estimated using calorimetry equations.

At 60 minutes post-consumption (end of rest period), there were no significant differences found for those that consumed the placebo or yerba maté for either resting BLC (1.4 ± 0.32 vs. 1.5 ± 0.30 mmol/l^-1) or resting RER (0.82 ± 0.08 vs. 0.81 ± 0.05). During exercise, at submaximal intensities (below 70% of VO₂ peak), yerba maté intake resulted in significantly lower RER (P < 0.001; analysis of variance [ANOVA] main effects) and higher FAO (P < 0.001; ANOVA main effects) compared to placebo intake. In addition, CHO was lower after yerba maté consumption compared to the placebo (P < 0.001; ANOVA main effects).

In terms of energy expenditure, yerba maté increased EE_FAO (P < 0.001) and decreased EE_CHO (P < 0.01), irrespective of exercise intensity increase (no interaction effects). Furthermore, there was a trend that yerba maté reduced BLC compared to the placebo (P = 0.066), although this was not significant. At maximal intensity, however, no significant differences were found for peak BLC, peak VO₂, peak power, or peak RER for those that consumed yerba maté compared to placebo.

The author concludes that acute ingestion of yerba maté enhances fat metabolism when consumed before light to moderate exercise, and does not negatively affect maximal exercise performance. The author does not attribute these effects to the caffeine (i.e., low content), but speculates other compounds (e.g., saponins, caffeoyl derivatives, and amino acids) may cause such effects. The results of this study are also in line with another study that demonstrated yerba maté consumption increased the resting metabolic rate.¹ This study was limited by its small sample size and, given that yerba maté is mostly commonly consumed as a tea, the use of capsules may have influenced results. Future studies will need to be larger and carefully assess the bioactive components, mechanisms, and the best method of administration (e.g., tea, capsule) of yerba maté when assessing its effects on weight loss, sport performance, and metabolic health outcomes.

—Laura M. Bystrom, PhD

Reference

¹Martinet A, Hostettmann K, Schutz Y. Thermogenic effects of commercially available plant preparations aimed at treating human obesity. Phytomedicine. 1999;6(4):231-238.