Yerba mate stimulates the brain. It is often used to aid memory and concentration. It is reputed to help coping with warm and humid weather.1 It is used as a tonic which stimulates and defeats physical and psychological tiredness.2 The stimulants in yerba mate are caffeine, theobromine and theopylline.3
Yerba mate has high contents of magnesium, manganese and potassium which help maintain the balance of electrolytes during weight loss caused by a high-protein diet and make up for the mineral deficiency caused by laxatives. 4
Yerba mate is a diuretic and therefore eases the symptoms of premenstrual stress syndrome (PMS) caused by the retention of liquids.4
Scientists have confirmed that yerba mate has antioxidant, anti-inflammatory and anti-cancerous properties, protective effects in relation to the heart, antifungal properties and is a stimulant. Yerba mate helps lower the levels of bad cholesterol (LDL), prevents obesity and helps weight control, helps digestion (stimulates the secretion of bile) and it is likely to help prevent the complications of diabetes.
It is commonly believed that free oxygen radicals are involved in various pathological conditions such as cancer, diseases of the circulatory system, inflammations and other ailments of the liver. Free radicals are found everywhere in the natural environment of human beings, but they can be found inside the human body as well. Reactive Oxygen Species (ROS) cause widespread damage to DNA.5 Antioxidants protect from the oxidative stress caused by the harmful increase of ROS.
A small test has been carried out to measure the effect of yerba mate on the susceptibility human plasma to oxidation and the expression of genes encoding antioxidant enzymes. It was found that after a period of drinking yerba mate the oxidation of lipids was considerably lowered. The level of antioxidants in the blood plasma increased as did the expression of genes encoding antioxidant enzymes. These results suggest that regular drinking of yerba mate could lead to improved antioxidation of the human organism not just by increasing the active ingredients but also by regulating the mechanisms which fight oxidative stress.6
A test carried out in 2009 showed that the feeding of yerba mate extracts to mice decreased the oxidation of unsaturated fatty acids in their livers.12
Results of a test carried out in 2008 showed the effect of yerba mate infusion on mice. It was found that a regular intake of the infusion increased the resistance of DNA strands to breaking induced by hydrogen peroxide and increased the effectiveness of the DNA repair process in liver cells exposed to hydrogen peroxide, regardless of the amount of yerba mate.13
Yerba mate has chemoprevention properties (prevents the development of cancer). It is cytotoxic, that is destructive, in relation to liver cancer cells (HepG2) in vitro and inhibits topoisomerases II.14
Yerba mate decreases the build-up of cholesterol in the walls of arteries preventing the oxygenation of LDL.15
102 people were given green and roasted yerba mate infusion 3 times daily for 40 days. Those who had normal cholesterol levels had their levels of bad cholesterol (LDL) decreased by 8.7%. Those with abnormal cholesterol levels showed a decrease in their bad cholesterol levels of 8.1 and 8.6% after 20 and 40 days respectively. Patients with abnormally high cholesterol concentrations in their blood who also took statins (that is drugs lowering their levels of cholesterol), had their levels of bad cholesterol LDL lowered by 10.0 and 13.1 % after drinking yerba mate for 20 and 40 days respectively. The levels of their good cholesterol HDL increased by 6.2% after 40 days.16
Experiments on mice have also proved that yerba mate lowers cholesterol LDL levels. Mice on a diet high in fats, when given yerba mate had their bad cholesterol level LDL decreased from 189.1 to 129.3 mg/dl.17
Tests carried out on 32 rabbits have shown that yerba mate can arrest the development of atherosclerosis. At the end of an 8 weeks experiment, changes in the level of cholesterol in the aorta were measured, as were the atherosclerotic changes. The rabbits which had a diet high in cholesterol and had been given approximately 400 ml of yerba mate extracts per day had half the amount of cholesterol in the aorta and 41% less atherosclerotic changes than the rabbits on the same diet that had been given water only. The observed changes in the level of cholesterol in blood serum were negligible.18
Other tests have shown a significant decrease of around 30% in cholesterol and around 60% in triglycerides in the blood serum of rats placed on a high-cholesterol diet that were given yerba mate.19
Paraoxonase 1 (PON-1) is an enzyme present in the molecules of lipoprotein HDL which protects the lipoproteins LDL from oxygenation. Oxygenated LDL (ox-LDL) makes it easier for atherosclerotic plaque to develop. The high level of activity of PON-1 prevents atherosclerotic lesions and thus the development of atherosclerosis. The effectiveness of PON-1 in the blood plasma is lowered by, amongst others, smoking cigarettes, diabetes and inflammatory conditions brought on by e.g. surgical procedures, inflammatory diseases or diabetes.
An experiment involving three groups of healthy volunteers measured their concentrations of paraoxanase 1 before and after drinking respectively 0.5l of yerba mate, 0.5l of milk and coffee or nothing. Those drinking mate had a 10% increase of PON-1 activity in relation to those drinking coffee and milk.20 Chlorogenic acid which is the main polyphenol present in yerba mate is of great importance in this respectively.21
Experiments on rats show that yerba mate helps the dysfunction of the heart muscle caused by ischaemia and subsequent restoration of blood circulation (reperfusion). The mechanism of this protection is dependent on nitrous oxide and leads to reduction of oxygenation damage in the heart.22
Two days old chicken embryos given liquid extracts of yerba mate and caffeine showed increased growth and production of new blood vessels and angiones. This result, although yet to be further researched, points to the possibility of using caffeine and yerba mate in prophylactics and treatment of circulatory disease.23
The regular intake of a herbal infusion of yerba mate, guarana (the seeds of Paullinia cupana) and damiana (the leaves of Turnera diffusa) was found to slow down the emptying of the stomach by an average of 53% and to decrease the time needed to feel satiated. This was confirmed in a double-blind trial, on 7 people.
In addition, overweight patients who took the infusion for 45 days had an average weight loss of 5.1kg (+/- 0.5) whilst patients who took a placebo had a weight loss of 0.3 kg (+/- 0.08). This was a double-blind trial of 47 people of whom 24 received an infusion and 23 received a placebo. The patients were asked not to alter their usual eating/diet habits and to take the infusion/placebo 15 minutes prior to their main meal.24
In clinical trials 98 people received over 12 weeks yerba mate in the form of a supplement which also had in it extracts of asparagus, green tea, black tea, guarana and kidney beans. The results showed a decrease in fatty tissues and a change in the Body Composition Improvement Index BCI. The test took the form of a double-blind trial with a control group taking a placebo. The allocation to groups was randomised.25
Overweight men and women who took yerba mate were seen to have a lowered respiratory quotient RQ, which signified the increased oxygenation (burning) of fats.26
Likewise tests on rats have confirmed that yerba mate has properties which inhibit obesity in diets high in fat content.28
Test results published in 2001 confirm that yerba mate slowly and gradually stimulates the secretion of bile.30
Non-enzymatic glycation (glycosolation) is the process of the bonding of protein molecule with sugar molecules. The end products of the process are the AGEs (Advanced Glycation Endproducts). Glycation is responsible for the development of complications of diabetes / hyperglycaemia. Glycation of haemoglobin, albumin and crystallin is very important in relation to diabetes. Glycation of collagen and other proteins leads to a stiffening of the walls of arteries and veins in patients suffering from diabetes. Glycation of crystalline of the eye lens allows the development of cataracts.31 AGEs are also likely to be contributing to the development of atherosclerosis, Age-related Macular Degeneration, Alzheimer’s disease, osteoporosis, osteoarthritis and age-related lung compliance decrease.32
In laboratory tests yerba mate extracts decreased glycation of proteins. Specifically, it reduced the level of production of AGEs. Green tea extracts did not show similar effects.33 Chlorogenic acid, caffeic acid and, to a lesser degree, oleanoic acid are the main anti-glycation substances of yerba mate. Quite often their effect is greater than that of amino guanidine (pimagedine), the common anti-glycation drug. Yerba mate contains many substances which are capable of synergic action and this could explain its anti-glycation properties.34
Chlorogenic acid is an inhibitor of glucose 6-phosphatase which plays a role in the metabolism of glucose. It is likely to be of importance in the reduction of the inappropriately high rates of hepatic glucose output often found in non-insulin dependent diabetes.35
Yerba mate lessened the acute lung inflammation in mice exposed to tobacco smoke.36
Yerba plant extracts have antifungal properties which slow down the growth of Malassezia furfur – the fungus responsible for skin problems such as dandruff. Yerba mate infusion could be an alternative topical relief for such ailments.37
Yerba mate triterpenoids are effective against Trypanosoma cruzi, a parasitic euglenoid trypanosomes which causes the Chagas disease in humans and animals.38
Extract from yerba mate leaves has a strong inhibitory effect on the activity of human neutrophil elastase (HNE) in vitro.39 HNE is an enzyme degrading elastin and collagen and is responsible for cell damage in emphysema and in rheumatoid arthritis. Elastase activity considerably increases with age which leads to reduced elasticity of skin and the development of wrinkles or stretch marks.Paweł Garski - Health benefits of yerba mate tea. YerbaMateInfo.com (publication date: 2011-02-03)