Arabica beans and robusta beans are two different species of coffee grown commercially for consumption as coffee. The general differences are those of taste, the conditions under which the two species grow and economic differences. Arabicas have a wider taste range, between varieties. They range in taste from sweet-soft to sharp-tangy. Their unroasted smell is sometimes likened to blueberries. Their roasted smell is perfumey with fruity notes and sugary tones.
Robusta taste range is neutral to harsh and they are often described as tasting grain-like, oatmeally. Their unroasted smell is often described as raw-peanutty. There are high quality robustas on the market but they are rare and reserved exclusively for the best robusta containing espressos.
The Green Coffee beans of the highest quality comes from Arabica beans. Coffee beans are naturally green, but they are usually roasted before being sold to the consumer. This is the process that turns them brown. As we know coffee beans are loaded with antioxidants and pharmacologically active compounds. Two of the most important ones are Caffeine and Chlorogenic Acid. Chlorogenic Acid is believed to be the main active ingredient in green coffee beans. That is, the substances that produces the weight loss effects . Unfortunately most of the chlorogenic acid is removed when coffee is roasted. For this reason, regular coffee beans won’t have the same effect.
It has strong anti-oxidant properties similar to other natural anti-oxidants like green tea and grape seed extract. These beans have polyphenols which act to help reduce free oxygen radicals in the body (in other words acting as good antioxidants). Green coffee bean extract is sometimes standardized to 30 to 50% chlorogenic acid, a compound present in coffee which has long been known for its beneficial properties.
The high level of antioxidants in green coffee bean extract may help the body fight toxins and free radicals. The free-radical theory of aging holds that antioxidants may slow down the process of aging.There have been indications that the chlorogenic acid in green coffee bean extract may help reduce the levels of homocysteine. Decreased levels of homocysteine may reduce the risk of heart problems. Chlorogenic acid may also have some potential to play some role prevent Type 2 diabetes, which is associated with high blood pressure and obesity, but these indications are very preliminary based on very limited research.
Green coffee may positively affect how our bodies absorb and use carbohydrates. As hypothesized in the animal studies, supplementing chlorogenic acid appears to reduce glucose absorption. This effect on glucose metabolism could play a protective role in diabetes management, and may also explain the effects on body weight. Green coffee extract may also positively affect blood vessels, which has major implications for heart health. Doses of between 140-720 mg per day have been shown to lower blood pressure in both rats and humans with high blood pressure
So, the potential benefits of green coffee bean extract and the chlorogenic acid contained in it are encouraging on many fronts, but also limited by virtue of the size of research studies and the lack of peer review.