Unlike synthetic drugs, natural products are difficult to patent.

And it takes hundreds of millions of research dollars to gain FDA approval for a health claim.

The difficulty of obtaining patents and FDA approval explains why few dietary supplements are backed by robust — and extremely costly — clinical evidence.

Every so often, promising lab results on a natural product will prompt a university to spend money on a preliminary clinical trial.

Curcumin is one of the few supplements to have received even preliminary clinical study, and the results of those — while inconclusive — are very promising.

Those results probably would have been much more promising, except that most of the published studies were conducted using older, very poorly absorbed curcumin supplements.

Let’s take a closer look at the history, challenges, and healing potential of curcumin, and how to identify effective supplements.

What is curcumin?
Curcumin comes from turmeric, a tropical plant (Curcuma longa) that’s closely related to ginger and lemongrass.

And it's ground turmeric root that gives curry powder its distinctive yellow-orange color.

Turmeric is a key medicine in Ayurveda — India’s ancient healing tradition — whose practitioners prescribe the root for a wide variety of ailments.

Its bold color comes from three polyphenol-type antioxidants called curcuminoids, which — like the polyphenols in other colorful plant foods — possess beneficial properties.

All three of turmeric’s colorful antioxidant pigments are collectively referred to as “curcumin”.

Foods made with whole turmeric are a wonderfully tasty way to get curcumin, but turmeric only contains about five percent curcumin.

To enjoy curcumin’s full benefits, you’ll need to take it in supplement form. And as we’ll explain, not all curcumin supplements are created equal.

Curcumin’s rise to prominence
Unlike many dietary supplements, curcumin is no Johnny-come-lately.

Harvard chemists discovered curcumin in turmeric in 1815, and its chemical structure was defined in 1910.

The first evidence of curcumin’s benefit for a human disease (cholecystitis) was published in 1937, and its ability to inhibit the growth of staphylococcus, salmonella, and tuberculosis was documented in 1949.

In the 1970s, scientists documented cholesterol-lowering, anti-diabetic, anti-inflammatory, and antioxidant properties of curcumin.

And in the 1980s, research revealed that curcumin exerts anticancer effects in isolated cells and in animals.

Since then, curcumin has been studied in hundreds of cell and animal experiments, and its effects in humans have been probed in more than 70 preliminary clinical studies.

Antioxidant/antiinflammatory star 
Curcumin’s rise to prominence really began in 1995, when scientists at the University of Texas MD Anderson Cancer Center discovered curcumin’s potent anti-inflammatory properties and related antioxidant effects.

Those scientists discovered that curcumin exerts strong anti-inflammatory and antioxidant effects via its so-called “nutrigenomic” effects on our working genes.

Curcumin can also enhance the production of internally produced antioxidant enzymes such as glutathione.

Importantly, those particular genetic effects suggested that curcumin might offer exceptionally broad health benefits.

Curcumin’s health promise
Curcumin has probably been subjected to more clinical studies than any supplements other than vitamins, minerals, and omega-3 fish oil.

However, as is the case with many supplements, few of these trials have been rigorous enough to permit statistically sound conclusions (i.e., randomized, double-blind, placebo-controlled, and of sufficient size and duration).

And, as we'll explain, most — though not all — of the human studies published to date have used "raw" cucumin, which is very poorly absorbed. (See “Absorption problems muddy the evidence”, below)

That said, preliminary clinical trials testing the effects of curcumin in people have generally produced positive results.

The clinical results suggest that curcumin may improve inflammatory conditions including cancer, cardiovascular disease, diabetes, dementia, arthritis, and various inflammatory bowel disorders.

Four years ago, scientists from the MD Anderson Cancer Center published the most extensive literature review to date.

They found substantial clinical evidence that curcumin benefited participants suffering from a variety of health conditions (Gupta SC et al. 2013):

As they wrote, “Some promising effects have been observed in patients with various pro-inflammatory diseases including cancer, cardiovascular disease, arthritis, uveitis, ulcerative proctitis, Crohn’s disease, ulcerative colitis, irritable bowel disease, peptic ulcer, gastric ulcer, gastric inflammation, psoriasis, diabetes, renal conditions, AIDs, cholecystitis, hepatic conditions, and chronic bacterial prostatitis.”

To that long list we’d add these observations, including findings from clinical studies published since their 2013 evidence review:

  • Alzheimer’s disease. Lab and animal studies show that curcumin possesses neuroprotective and cognitive-enhancing properties, which suggests that hypothetically, it should help prevent or ameliorate Alzheimer’s and other forms of dementia. The few clinical trials conducted to date have not detected significant benefits from supplemental curcumin. However, as the researchers behind the negative studies emphasized, the curcumin used was unenhanced and very poorly absorbed, and some trials involved people with advanced disease, so the jury remains out.
  • Cancer. As MD Anderson Cancer Center researchers wrote in 2013, “… curcumin has exhibited activities against numerous cancer types in human clinical trials,” and as researchers from Italy’s University of Messina wrote earlier this year, “Curcumin is a promising molecule for the prevention and treatment of cancer.” More clinical studies are underway to determine whether curcumin — alone or with chemotherapy — can benefit people with common cancers.
  • Diabetes. Oxidative stress (free radicals) and inflammation play major roles in Type 2 diabetes and its cardiovascular complications. Laboratory and preliminary clinical evidence shows curcumin provides antioxidant, anti-inflammatory, and glucose-lowering benefits that might help prevent or treat Type 2 diabetes.
  • Obesity. Low-grade chronic inflammation promotes weight gain, and vice versa, especially if you gain weight around the midsection. Curcumin can help regulate fat metabolism and mimic the anti-inflammatory benefits of caloric restriction. Experimental evidence suggests that curcumin may help people lose weight and reduce the severity of obesity-related diseases.
  • Osteoarthritis. Preliminary clinical evidence suggests that enhanced forms of curcumin may improve osteoarthritis symptoms.
  • Premenstrual Syndrome (PMS). Two recent clinical studies from Iranian universities found that curcumin alleviated PMS symptoms, and identified the specific ways in which it probably produced those benefits.
  • Rheumatoid arthritis (RA). Researchers in one trial compared curcumin with a nonsteroidal anti-inflammatory drug (NSAID) in 18 patients with RA. Two weeks of taking 1.2 grams of curcumin per day improved morning stiffness, walking time, and joint swelling as well as an NSAID. A more recent study among 45 RA patients found curcumin comparable to a commonly prescribed NSAID (diclofenac sodium) for reducing tenderness and joint swelling.

Absorption problems muddy the evidence
Curcumin in its "raw" state is very poorly absorbed.

As researchers put it a few years back, “The potential health benefits of curcumin are limited by its poor solubility, low absorption from the gut, rapid metabolism and rapid systemic elimination.”

Most of clinical trials published to date employed raw curcumin, so the true health potential of curcumin awaits full revelation.

Fortunately, the absorption problem has been overcome using several different approaches, but most methods of enhancing absorption make curcumin very costly.

The simplest — and most cost-effective way by far — to enhance absorption is to combine curcumin with turmeric’s own “volatile” compounds, which may also provide some health benefits.

When you compare the cost of various “enhanced” curcumin supplements, the only one that combines curcumin with turmeric’s volatile oils — called BCM-95 — comes out on top.

(We hope that all clinical trials from now on will use enhanced forms of curcumin, which would provide a much fairer test of this extraordinary plant extract.)

In addition, curcumin is absorbed much better when it's consumed along with fats, either from foods, or from supplements such as fish oil, which also delivers beneficial omega-3s.

That’s why, for optimal absorption, it’s wise to take curcumin supplements with a meal that provides significant amounts of fat.

Interestingly, lab research shows that combining curcumin with omega-3 fatty acids and antioxidants may promote cancer cell apoptosis (“suicide”) and protect the body’s defensive natural killer (NK) cells against degradation.

And one study found that feeding cancerous mice fish oil plus curcumin shrank their tumors significantly.

Curcumin dose and safety considerations
Human studies suggest that curcumin is generally safe, even at high doses.

Specifically, they’ve found curcumin safe at doses of up to 10 to 12 grams a day over periods of up to three months.

That said, curcumin can affect the efficacy or toxicity of pharmaceutical drugs that are either transported by P-glycoprotein (PCP) or are substrates of cytochrome-type enzymes, including some cancer chemotherapy drugs.

So if you’re taking prescription drugs, check with your doctor or integrative physician before taking curcumin.

Along with these precautions, we should note some myths about curcumin safety including false allegations that it promotes kidney stones and gallstones.

Although the oxalates in turmeric promote formation of kidney stones, these compounds are virtually absent from curcumin.

Curcumin actually prevents gallstone and kidney stone formation in rodents, in part by promoting contraction of the gallbladder. However, that contracting effect may worsen the symptoms of existing gallstones.

People with bile duct obstruction, gallstones, and GI disorders including stomach ulcers and hyperacidity disorders should not take curcumin without the guidance of a physician.

Likewise, a doctor should monitor anyone with ulcers or GI inflammation who uses curcumin.

Finally, although there are no specific contraindications for pregnancy — and some evidence that curcumin may promote a healthier pregnancy — it makes sense for a pregnant women to check with her physician.


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