Coffee beans are naturally green, but they are commonly roasted before being sold to the consumer. This is the process that turns them brown.
Chlorogenic acid (CGA) is the main active ingredient in green coffee beans. That is the compound that produces the weight loss effects.
Green coffee beans usually contain 6 percent to 7 percent of this substance with roasted coffee beans having less, as the roasting transforms CGA into other molecules.
One of the biggest proponents of green coffee extract for weight loss has been Dr. Oz, who cited a study that tied green coffee to weight loss, asserting that people who took it lost an average of 18 pounds in 6 weeks.
One major problem with that study, published in the journal Diabetes, Obesity and Metabolic Syndrome, was that it involved only 16 subjects.
Remember! The majority of the studies into the effects of CGA on humans have been sponsored by industry with a considerable investment in the positive outcomes of those studies.
Sponsorship bias or funding bias is a well-known and recognized phenomenon. In 2012, the Cochrane Collaboration published one of their famous systematic reviews into the issue, finding that:
“Sponsorship of drug and device studies by the manufacturing company leads to more favorable results and conclusions than sponsorship by other sources.”
For example, in 2011, a review or meta-analysis of a number of research studies on the effectiveness of CGA for weight-loss was published in Gastroenterology Practice and Research.
The reviewers established that while the results of the studies showed promise, the methodology of many of the studies was poor. Additionally, an author of one of the studies reviewed had received funding from a company that manufactures green coffee extract.
Side effects of chlorogenic acid
Green coffee does contain caffeine, which can have many side effects when consumed.
This includes rapid heartbeat, lethargy, indigestion, trouble breathing, anxiety, jitteriness, increases the risk of heart attacks among young adults, and increases the amount of calcium, flushed out in the urine – which in turn might weaken bones. Also, despite the common wisdom of drinking coffee to recover from too much alcohol, in reality, caffeine doesn’t help your body process alcohol any faster.
Caffeine provides no nutritional value. It’s tasteless, so you don’t automatically know if it’s in your food.
In addition, studies suggest caffeine contained in green coffee bean extract can alter the way people, particularly those with diabetes, absorb sugar. It’s been noted to cause both increases and decreases in blood sugar. So, if you have diabetes, use caffeine with caution and monitor your blood sugar regularly.
CGA has been linked with increased levels of the protein amino acid homocysteine (a naturally occurring amino acid produced as part of the body’s methylation process). Increased homocysteine levels are linked to an increase in the risk of cardiovascular disease.
Furthermore, the absorption of minerals such as selenium, iron, magnesium, and zinc is reduced when chlorogenic acid is taken within about 60 minutes of the meal.
Since green coffee bean extracts affect fat metabolism, women who are breastfeeding or pregnant should not take the pure green coffee extract.
People who are on medication for serious illnesses, such as diabetes or heart disease, should also avoid green coffee capsules. Additionally, children should also refrain from consuming green coffee supplements.
While experts continue to experiment and analyze the potential health benefits of chlorogenic acid in green coffee bean extract, always speak to your healthcare specialist before taking any supplements.