Curcumin bioavailability: The need to compare apples with apples

Published on April 02, 2013 by Dr. Traj Nibber

Curcumin is the largest of the three curcuminoid components present in the root of Curcuma longa. Curcumin is probably the most widely studied natural product on the planet, and has a multitude of health benefits. These range from improving heart, liver, brain, and kidney function to preventing cataracts and gall bladder stones, having a powerful anti-cancer effect to being acknowledged as one of the strongest anti-inflammatory molecules on the market. However, curcumin has one drawback; it has poor bioavailability of around 2-3%.

Bioavailability is the amount of active molecule that reaches the target site, be it the knee joint, the nerve cell in the brain or the cancer tissue. Unfortunately, to measure the amount present at the actual target site is very expensive and labour-intensive, thus most researchers measure the amount of curcumin that is present in the blood as a surrogate marker of bioavailability. The procedure involves giving volunteers a known dose of curcumin-95, the highly purified curcumin molecule, and measuring the amount of curcumin present in the blood at 0, 1, 2, 4, 6, 8 and 12 hours. The procedure is then repeated, but this time using your improved formulation and then comparing the area under the curve (AUC). The difference is a relative measure of how many times the new formula is better (hopefully) than the standard curcumin-95.

The key issue is to measure and report free levels of curcumin in the blood. Unfortunately, it turns out that not all companies play by the same rules. Most companies just measure the total amount of curcumin present, whether it is in the free curcumin form or the various metabolites like glucuronide or sulphate. The reason is because if they measured free curcumin there would be very little present, as most of the curcumin has been acted upon or metabolized by the phase 2 enzymes and quickly converted into various metabolites. It is not to say that the metabolites are not active, indeed they most likely are, but it isn’t free curcumin, upon which most of the research has been conducted. Moreover, it is only the free curcumin that is able to get past the blood brain barrier (BBB) and into the brain to impact cognitive health. The metabolite forms aren’t able to get past the BBB due to their structure being altered through the addition of the glucuronide or sulphate groups. Measuring metabolites rather than free curcumin, and then claiming that their curcumin formulation is bioavailable, is not a justifiable conclusion. You are not comparing apples with apples.

Few companies have formulations that actually deliver free curcumin in the blood. One such product is Longvida, a patented product developed by the Alzheimer’s Lab at University of California at Los Angeles (UCLA). The researchers Drs. Bruce Cole and Sally Frutchey took years and tested over 200 formulations before coming up with their solid lipid curcumin particle. This delivery system has been clinically tested to confirm not only bioavailability but also bioactivity. First, in a human 2010 study in Mumbai (Gota et-al 2010), clinicians treated bone cancer patients with Longvida and found that it was over 100 times more bioavailable than curcumin-95! This is far better than any other product on the market which at best has reported a thirty-fold increase; even then it wasn’t the free curcumin form. In addition, the Longvida form had a much longer half-life than other forms. What this means is that the Longvida form stays in the body for a much longer time, and thus provides continued release to the cells and tissues.

But what does this hugely increased bioavailability actually mean in terms of health benefits? The Gota study actually reported improvement in various health parameters, such as reduced pain and nausea, improved appetite, and overall improved quality of life, as well as improving the remission rate from 2% to 19%. The second study, from Ohio State University, was published last year (Di Silvestro, 2012), and reported a significant reduction of the beta amyloid plaque, which is thought to be one of the culprits in the causation of Alzheimer’s disease. An even more remarkable finding was that this reduction was observed in just thirty days at a small dose of 80mg of Longvida curcumin!

It is important that we understand what bioavailability means, and know whether companies are reporting their findings based upon free curcumin, or a changed metabolite form.

Gota V et-al “The safety and Pharmacokinetic of solid lipid curcumin particle in osteosarcoma patients and healthy patients” Journal of Food Agriculture Chemistry 2010, 58; 2095-2099

Di Silvestro R et-al “Diverse effects of a low dose supplement of lipidated curcumin in healthy middle aged people” Nutrition Journal 2012, 11:79;1-8