Have you heard of yerba mate? Made from dried, ground leaves and twigs of a tree indigenous to South America (Ilex paraguariensis), yerba mate is a caffeinated beverage that is steeped in hot water and drunk through a metal straw inserted into a dried gourd. This method of consuming yerba mate is known as mate cebado. Like coffee, tea and colas, yerba mate contains a stimulant (xanthine), and on average, contains about 330 mg of caffeine for every (1.5 quarts) consumed.
Why the interest? Well, coffee and consumption of caffeine have been linked to lower bone mineral density, accelerated bone loss and increased fracture risk, all major red flags for women as they age who become increasingly at higher risk for osteoporosis. Conversely, beverages like green and black tea, both of which have considerable caffeine content, are reportedly protective of bone. So, what about yerba mate and your bones?
In study in the January 2012 issues of Bone, researchers looked at the effect of yerba mate in postmenopausal women who drank at least a liter per day (prepared as mate cebado) for five years. These women were sedentary, did not smoke or also drink more than three cups of coffee or tea daily, were not on HRT or bisphosphonate therapy and used alcohol moderately. Yet, when they were compared to women of similar age and menopausal status who did not drink yerba mate, they were found to have higher bone mineral density levels at both the spine and hip. And, when researchers delved deeper, they found that only one other factor — body mass index — similarly and positively affected these BMD measures.
However, yerba mate contains high levels of xanthine, the same stimulant implicated in coffee’s detrimental effect on bone, implying that it wouldn’t be bone protective, right? A possible explanation for these positive bone effects is that yerba mate contains organic compounds, such as in particular, polpyphenols (antioxidant chemicals), flavonoids and alkaloids that may confer these positive benefits.
Before you start changing your caffeine habits, there are a few things that you need to know. Yerba mate has been linked to esophogeal and oral cancer and cancer of the larynx (although this may be associated with the temperature of the drink as well as the compound itself). Because it contains such a high level of stimulant, it may not be safe for people with high blood pressure who are especially sensitive to caffeine or who are taking blood pressure medications. Finally, there is some indication that in high doses, yerba mate can negatively affect the liver. So, it’s a beverage that’s best in moderation (take note lovers of Guayaki Organic Energy Shots!).
Me? I’m going to stick with my coffee habit and counteract any negative bone impact through weight bearing exercise. Still, it’s good to know that yerba mate may be an alternative worth looking into.