Mate

Studies in people

• Open question

  Oesophageal cancer risk³

  Drinking mate very hot may raise oesophageal cancer risk, not the PAH chemicals in mate itself.

• Benefit

  Breast cancer risk⁴

  In people, drinking more mate was linked to lower breast cancer risk, even when antioxidant intake varied.

• Open question

  Cholesterol levels in people with HIV⁵

  In people with HIV, yerba mate did not raise "good" cholesterol, but dark chocolate did.

• Benefit

  Muscle recovery after exercise⁶

  In men, drinking mate tea sped up muscle strength recovery in the first day after hard exercise.

• Benefit

  Blood sugar and cholesterol⁷

  In people with type 2 diabetes, drinking mate tea lowered fasting blood sugar, long-term blood sugar, and LDL cholesterol.

• Benefit

  Cholesterol and blood fats¹⁰

  Overweight women who drank yerba mate daily lowered their total and LDL cholesterol.

• Benefit

  Inflammation and oxidative stress¹¹

  In men, drinking mate tea lowered signs of inflammation and boosted antioxidants in the blood.

Animal and lab studies only

• Concern

  DNA damage in cells¹⁸

  In lab studies, mate-chimarrão damaged DNA in bacteria and human cells, but not in rat cells.

• Benefit

  Weight gain and body fat¹⁹

  In animal studies, mate tea slowed weight gain and lowered blood fats and liver fat in mice fed a high-fat diet.

Study type not stated

• Open question

  Heart and inflammation¹²

  Yerba mate has compounds that may help the heart and calm inflammation, but drying it can form unwanted chemicals.

Found in some samples or products

These come from where it was grown, how it was processed or cooked, or what it was made into. They are not about the ingredient itself, so the signal does not count them.

• Esophageal cancer risk¹³

  Mate is often dried over smoke, leaving PAHs that may pass into the drink, but how much is still unknown.

• Mercury in tea drinks¹⁵

  Yerba mate held about twice the mercury of other teas, though still within EU limits.

• Pesticides in brewed tea¹⁶

  Pesticides on yerba mate leaves can end up in the brew when you drink mate.

How it’s made and used

• Mouth bacteria⁸

  In people, drinking yerba mate was linked to a more varied mix of mouth bacteria.

• Muscle strength after exercise⁹

  In men, drinking yerba mate before lifting did not change how much they could lift.

• Antioxidants after roasting¹⁴

  Toasting mate leaves lowers their chlorogenic acids, but toasted mate still holds more than most foods.

• Caffeine and plant compounds in drinks¹⁷

  In drinks made from mate, terere had about 2.5 times more xanthines than coarse-ground chimarrao.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.

Expert panels that weigh all the research. Shown for context: the signal at the top does not count them. IARC rates whether something can cause cancer at all, not how likely it is at the amounts in food.

• WHO cancer agency (IARC), 2016

  For mate drunk not very hot: not enough evidence to say whether it causes cancer in people (Group 3).