Green coffee bean extract is a popular weight loss supplement in the world. Coffee beans are naturally green but due to roasting they become brown in colour. Green coffee beans extract containing 45% chlorogenic acid is known to have a number of health benefits.
Mechanism of action
Chlorogenic acid is the main constituent of green coffee beans and this is the substance that is known for producing its weight loss effects. Chlorogenic acid is removed when the coffee beans are roasted. Therefore, cholorogenic acid is only present in unroasted green coffee beans.
Chlorogenic acid present in green coffee beans has a thermogenic effect on the body which implies that it increases the temperature of the body and the metabolic rate. The increased rate of metabolism promotes fat burning which reduces weight. Some studies conducted on humans have shown that chlorogenic acid reduces carbohydrate absorption from the digestive tract which in turn reduces the blood sugar level.
Other studies conducted on animals have shown that chlorogenic acid can reduce the fat absorbed from the diet, bring about a reduction in the amount of fat stored in the liver and enhance the function of the fat burning hormone named adinopectin. In addition, chlorogenic acid has also been shown to improve cholesterol levels in the body which is beneficial in preventing heart disease.
A study was conducted on 30 overweight persons for a period of 12 weeks. They are divided into two groups. One group was given regular instant coffee while the second group consumed instant coffee supplemented with 200mg of green coffee bean extract. There was no alteration in the diet and exercise patterns of either group.
The result showed that the individuals of the group consuming instant coffee with green coffee bean extracts lost 5.4kg while the individuals of the other group taking only instant coffee lost merely 1.7kg. Furthermore, the green coffee extract group lost 3.6% of the body fat while it was just 0.7% for the other group.
There have been many studies that have reported a significant loss of weight in people taking green coffee bean extract but some of these studies have received opprobrium from health experts due to the methodology used and the fact that that they were sponsored by companies selling green coffee beans.
Altogether, there is a lack of adequate clinical and scientific evidence regarding the weight loss potential of green coffee beans extract. Further research and conclusive data are required before it can be clearly established as a weight loss supplement.
Green coffee beans contain caffeine which can cause some side effects such as rapid heartbeat, nausea, headache, upset stomach, anxiety and jitteriness when consumed in excess amount. 400mg or less is considered a moderate dose of caffeine every day. Green coffee bean extract should not be consumed by pregnant or breastfeeding women because there is no evidence regarding its safety during such conditions. It should also not be consumed by children. Allergic reactions to green coffee beans have also been reported in some people.