Supporting Healthy Glucose Metabolism with Berberine
Meredith Murray ND
Berberine is an isoquinoline alkaloid that is responsible for the bright yellow color of herbs such as Berberis vulgaris, Coptis chinensis, and Mahonia aquifolium. Many are familiar with the antimicrobial capabilities of berberine, however, it has many other useful properties. Berberine containing plants have been utilized historically for centuries, but in the last few decades, berberine has also been studied for its ability to support healthy cholesterol, immune system activity, and address bacterial imbalances.
Recent human studies have demonstrated that taking berberine, in addition to diet and lifestyle modification, had a greater benefit than just diet and lifestyle change alone for achieving healthier blood sugar control, as indicated by improved hemoglobin A1c and lipid levels.
There are four metabolites of berberine that are created in the body depending on whether berberine is given orally or intravenously. When taken orally, beberine’s first pass elimination occurs in the small intestine and the accumulation occurs in the liver (as well as in other organs secondarily). Berberine has a low rate of absorption through the small intestine (approximately only 5%). This is because it acts as a substrate for a transporter that removes it from cells.
The actions of berberine have been studied in cells, animals, and humans. At a cellular level, it has been shown that berberine can act on the cells of the liver, arterial wall, pancreatic beta-cells, adipocytes, and myocytes. The main way berberine has cellular effects is through the protein AMPK (AMP-activated protein kinase). When AMPK is activated, it stimulates processes such as fatty acid oxidation and inhibits processes such as cholesterol synthesis and gluconeogenesis.
In cellular in-vitro studies, it has been shown that berberine can limit oxidative stress and restore insulin secretion to beta-cells which were exposed to high-glucose. This is done by the stimulation of the AMPK and subsequent downstream effects.
Another action of berberine which was studied in various human cell lines, was that it can increase insulin receptor expression which then helps to promote insulin signaling. The action was replicated in a two-month human study which resulted in lowered glucose and insulin levels. This was validated in several subsequent human studies showing the ability of berberine to increase insulin receptors which then increases glucose uptake and lowers glucose levels.
The other mechanism being considered for the metabolic effects of berberine is its antimicrobial properties. It is now known that the gut microbiota has a direct influence on metabolic syndrome and diabetes – both conditions resulting from blood sugar imbalance. It is being evaluated whether changes to the gut flora as a result of berberine’s antimicrobial activity also plays a positive role in supporting healthy glucose regulation.
As mentioned previously, berberine has a low bioavailability when taken orally. In order to improve this aspect and potentially increase the benefits, there have been a few studies looking at complementary products that can increase absorption. One additional herb that has shown to improve bioavailability of berberine is Silybum marianum (milk thistle). Milk thistle acts as an inhibitor of the transporter that limits berberine absorbability.
Overall, human studies using berberine for metabolic support have used a dose of 500mg three times daily for up to three months. The results indicate that berberine can support healthy lipid and glucose metabolism.
I have witnessed the success of my own patients who include berberine for supporting healthy glucose and lipid balance. However, because berberine also has an effect on the expression of various cytochrome P450 pathways in the body and can accumulate in the liver, I always consider whether it’s appropriate based on other medications and medical history. I recommend monitoring liver function with routine bloodwork.
Pirillo A, Catapano AL. Berberine, a plant alkaloid with lipid- and glucose-lowering properties: From in vitro evidence to clinical studies. Atherosclerosis. 2015;243(2):449-461. doi:10.1016/j.atherosclerosis.2015.09.032.