Health Benefits of Green Coffee

How Unroasted Beans Can Aid in Weight Loss, Diabetes, and More

Medically reviewed by

on July 18, 2020

Green coffee is raw, unroasted coffee beans. — Margarita Komine/Moment/Getty Images

Health Benefits

Green coffee contains chlorogenic acid, a powerful antioxidant that tends to break down when coffee beans are roasted. Some research suggests that the retention of chlorogenic acid in green coffee is largely responsible for the health benefits.

Although research is limited, there is evidence that green coffee can stimulate metabolism (the conversion of calories and oxygen into energy). Metabolism doesn't only imply digestion; it dictates how well all cells in the body function, including those of the heart, lung, kidney, liver, and brain.

Here is just some of what the current research says about the benefits of green coffee:

Weight Loss

Green coffee may be moderately beneficial to those trying to lose weight, according to a review of studies published in Gastroenterology Research and Practice. Of the three clinical trials included in the review, each showed that green coffee extract was significantly more effective than a placebo in lowering body weight.

While the researchers admitted the studies were poorly designed, they concluded that there was enough congruence to suggest that green coffee was a safe and potentially beneficial weight loss aid.

A 2013 review of studies published in the Journal of Evidence-Based Integrative Medicine went even further.

In their review five clinical trials and one meta-analysis, the researchers reported that people lost between 1 kilogram (kg) to 8 kg of body weight—or roughly 2 to 17 pounds—as a result of green coffee extract.

As with the 2011 review, the conclusions were limited by the generally poor quality of the reviewed studies.

Diabetes

Chlorogenic acid is one of the most abundant polyphenols in the foods we eat. Polyphenols are plant-based chemicals with antioxidant properties. They not only fight free radicals that damage cells, but they are also believed to help regulate blood sugar (glucose).

A 2010 study reported that chlorogenic acid delivered at a dose of 5 milligrams per kilogram (mg/kg) of body weight was able to normalize glucose levels in diabetic rats.

In humans, the daily consumption of three to four cups of decaffeinated coffee containing high concentrations of chlorogenic acid reduced the risk for type 2 diabetes by 30 percent, according to 2009 research from Australia.

While it is presumed that green coffee, which has higher quantities of chlorogenic acid, may provide even greater protection, this has yet to proven in research.

High Blood Pressure

There is evidence that green coffee can lower blood pressure. According to a 2006 study from Japan, green coffee extract prescribed at 140 mg per day for 12 weeks reduced the systolic blood pressure by 5 mmHg and diastolic blood pressure by 3 mmHg in mildly hypertensive adults.

While encouraging, this doesn't mean that green coffee will benefit everyone with high blood pressure. This is especially true for people with caffeine sensitivity in whom green coffee may trigger the same symptoms as regular coffee, including increased blood pressure.

Interestingly, none of the participants in the Japanese trial experience changes in weight or body mass.

Alzheimer's Disease

As far-fetched as it may seem, green coffee can potentially prevent or reduce some of the cognitive and neuropsychiatric symptoms of Alzheimer's disease.

Chlorogenic acid has a weak stimulatory effect, about a third as potent as caffeine. While it doesn't give anywhere near the same "kick" as caffeine, it can elevate moods and with less risk of jitteriness or irritability.

Animal studies suggest that green coffee may improve brain function as well as mood. According to a 2012 study in Nutritional Neuroscience, the antioxidative properties of green coffee extract helped retain normal brain metabolism in mice compared to mice who were not given the extract. Declines in brain metabolism are key indicators of Alzheimer's risk.

A 2017 review of studies echoed these claims, suggesting the green coffee extract alleviates the oxidative stress on the brain in such a way as to be "neuroprotective." Future research will likely measure how robust this protection may be.

The same benefits may extend to neurodegenerative disorders like Parkinson's disease.

Colorectal Cancer

The benefits of green coffee in colorectal cancer prevention is even less clear.

On the one hand, animal studies have long shown how polyphenols in coffee can help protect against the formation of colon tumors. It has been suggested that green coffee, which is composed of 14 percent chlorogenic acid, may enhance this effect.

On the flip side, coffee contains compounds that may increase the risk of colorectal cancer, either by promoting the mutation of cells or causing breakdown of cellular DNA. Whether these carcinogenic compounds are created during the roasting of the beans is not yet clear.

In the end, these opposing forces neither appear to promote nor prevent the development of colorectal cancer. Until research can show otherwise, it would be safe to assume the same with green coffee.

Possible Side Effects

Green coffee and green coffee extracts are generally considered safe for adults. With that being said, little is known about the long-term safety of green coffee extract or supplements.

As with regular coffee, green coffee may cause side effects, particularly those with caffeine sensitivity. These include:

Insomnia
Nervousness
Irritability
Stomach upset
Nausea
Increased heart rate
Headache
Ringing in the ears (tinnitus)

There is some concern that the long-term or excessive consumption of green coffee may increase the risk homocysteinemia (the excessive buildup of the amino acid homocysteine linked to heart disease and miscarriage).

There are no known drug interactions with green coffee.

Dosage and Preparation

There is no standardized dosing recommendation for green coffee extracts or supplements. Generally speaking, it is best to stay within the recommended dose on the product label if only to avoid side effects..

What to Look For

Green coffee can be found in many natural foods stores and some grocery stores. Many come in single-serve packets. Unlike regular coffee, whose aroma and flavor are the result of roasting, green coffee is almost entirely without aroma and has a slightly bitter taste.

Green coffee extracts and supplements can also be found online and in stores specializing in dietary aids. Some of the extracts are packaged as tinctures, which you take using a dropper. Others come in tablet or gel cap formulations.

It is important to remember that supplements are largely unregulated in the United States. There can be significant differences in quality and doses between one brand and the next.

To ensure safety and quality, only choose supplements tested and approved by a recognized certifying body like the U.S. Pharmacopeia (USP), NSF International, and ConsumerLab.