The English word curry encompasses many Indian spice mixtures.
Curry comes from the Tamil (South Indian) word “kari”, meaning soup or sauce.
A common thread runs through most curries … the bright-yellow spice called turmeric.
Turmeric is a member of the ginger family, long used in India and China as a folk medicine, food preservative, coloring agent, and spice.
The deep-orange root of the turmeric plant comes from three polyphenol compounds called curcuminoids … one of which (curcumin) has come to mean the trio as a whole.
Curcuminoids are polyphenols … the “antioxidants” that famously abound in tea, cocoa, culinary herbs and spices, berries, grapes, onions, and many other fruits and vegetables.
Polyphenols exert antioxidant and anti-inflammatory effects in the body, via indirect, “nutrigenomic” influence on our genes.
Like other polyphenols, curcuminoids provide cardiac and cancer-preventive properties … but it ranks among the most powerful and versatile member of the large polyphenol family.
For our coverage of recent studies, see the sidebar titled “Curcumin for health”.
Curcumin's health potential flowers via new forms
Last March, scientists from Australia's Queensland University has good things to say about curcumin.
As they wrote, “A number of studies have shown that dietary curcumin reduces inflammation and delays or prevents obesity-induced insulin resistance and associated complications ...” (Maradana MR et al. 2013)
However, their comments were couched in the context of a complaint about the poor oral absorption of curcumin, which has hindered research.
Fortunately, as they wrote, “New improved methods of delivering curcumin are being developed … that increase absorption and bioavailability of curcumin. Development and refinement of these technologies will enable … improved therapeutic outcome[s].” (Maradana MR et al. 2013)
Now, a pilot clinical trial from Thailand adds even more luster to the vibrant yellow color in curry.
Clinical trial detects diabetes-deterring effects from curcumin
Scientists from Thailand's Srinakharinwirot University report exciting findings from a small, “pilot” clinical trial.
They recruited 237 people diagnosed with “pre-diabetes” … a condition defined by these outcomes on three standard tests:
Glycated hemoglobin (HbA1C) level of 5.7 to 6.4 percent.
Fasting plasma glucose level between 100 and 124 mg/dL.
Blood glucose level between 140 and 199 mg/dL following oral glucose administration
The participants were randomly assigned to receive one of two daily regimens for nine months:
The scientists examined each volunteer a upon enrollment and at three, six and nine months, collecting data on body weight, waist circumference, glucose tolerance, insulin resistance, glycated hemoglobin, C-peptide and other risk factors.
At the end of the trial, no cases of diabetes developed among those who received curcumin.
In contrast, 16.4 percent of the placebo group developed diabetes (i.e., a fasting plasma glucose level of 126 mg/dL or higher, an oral glucose tolerance test level of 200 mg/dL or higher, or an HbA1C of 6.5 percent or more).
Compared with the placebo group, the curcumin group displayed better metabolic health in four key areas:
Higher adiponectin levels
Reduced insulin resistance
Better-functioning pancreatic beta cells, which store and release insulin
The best news was reduced insulin resistance, because this hormone prompts cells to absorb and use sugar (glucose) for energy.
Diabetes develops if the body either does not produce enough insulin or if its cells become “resistant” to the effects of insulin, causing glucose to build up in the blood.
Unneeded dietary sugar (glucose and fructose) is a common excess in the American diet, and insulin prompts the body store excess amounts in muscle, fat, and liver cells … instead of sitting in your blood, which promotes diabetes.
Why does adiponectin help deter diabetes?
This so-called “starvation hormone” promotes insulin sensitivity, discourages insulin resistance, and plays a critical role in regulating fat storage.
When adiponectin levels are high, the body stores excess fat in fat cells (adipocytes), to protect against possible starvation during lean times … hence its nickname.
Fat deposited because of the actions of adiponectin lie primarily in the subcutaneous tissue located, as the name implies, under the skin.
As we accumulate more total body fat, adiponectin levels drop and the body begins storing fat in the abdomen, heart, liver, and muscles, which drives the chronic inflammation linked to heart disease and diabetes.
The authors said curcumin may prevent the progression of pre-diabetes to diabetes by maintaining healthy beta cell function.
Inflammation is known to degrade beta cell function, thereby hampering insulin production.
Importantly, the Thai team noted that the rise in adiponectin levels seen in the curcumin group helped lower inflammation.
No significant adverse effects were reported by or observed in the curcumin group.
As the authors said, “Our study showed that the curcumin extract can effectively prevent the pre-diabetes population from developing type 2 diabetes mellitus ... In addition, the curcumin treatment appeared to improve overall function of beta cells ...” (Chuengsamarn S et al. 2012)
And they added a key point for consumers: “Because of its benefits and safety, we propose that curcumin extract may be used for an intervention therapy for the pre-diabetes population.” (Chuengsamarn S et al. 2012)
Omega-3s from fish help, too
But omega-3s also exert “epigenetic” effects that appear highly relevant to the risk and severity of diabetes.
Like the diabetes-control drugs rosiglitazone (Avandia) and pioglitazone (Actos), omega-3s act on our cells' peroxisome proliferator-activated receptors (PPARs) … more weakly but very safely. Among other things, PPARs act on genetic switches that regulate lipid (fat) metabolism.
Curcumin for health: Broad research reveals broad benefits
Chuengsamarn S, Rattanamongkolgul S, Luechapudiporn R, Phisalaphong C, Jirawatnotai S. Curcumin extract for prevention of type 2 diabetes. Diabetes Care. 2012 Nov;35(11):2121-7. doi: 10.2337/dc12-0116. Epub 2012 Jul 6.
Jin QH, Shen HX, Wang H, Shou QY, Liu Q. Curcumin improves expression of SCF/c-kit through attenuating oxidative stress and NF-κB activation in gastric tissues of diabetic gastroparesis rats. Diabetol Metab Syndr. 2013 Mar 1;5(1):12. doi: 10.1186/1758-5996-5-12.
Li Y, Zhang Y, Liu DB, Liu HY, Hou WG, Dong YS. Curcumin attenuates diabetic neuropathic pain by downregulating TNF-α in a rat model. Int J Med Sci. 2013;10(4):377-81. doi: 10.7150/ijms.5224. Epub 2013 Feb 20.
Maradana MR, Thomas R, O'Sullivan BJ. Targeted delivery of curcumin for treating type 2 diabetes. Mol Nutr Food Res. 2013 Sep;57(9):1550-6. doi: 10.1002/mnfr.201200791. Epub 2013 Mar 14.
Margina D, Gradinaru D, Manda G, Neagoe I, Ilie M. Membranar effects exerted in vitro by polyphenols - quercetin, epigallocatechin gallate and curcumin - on HUVEC and Jurkat cells, relevant for diabetes mellitus. Food Chem Toxicol. 2013 Mar 4. doi:pii: S0278-6915(13)00155-5. 10.1016/j.fct.2013.02.046. [Epub ahead of print]
Oner-İyidoğan Y, Koçak H, Seyidhanoğlu M, Gürdöl F, Gülçubuk A, Yildirim F, Cevik A, Uysal M. Curcumin prevents liver fat accumulation and serum fetuin-A increase in rats fed a high-fat diet. J Physiol Biochem. 2013 Feb 22. [Epub ahead of print]
Takikawa M, Kurimoto Y, Tsuda T. Curcumin stimulates glucagon-like peptide-1 secretion in GLUTag cells via Ca2+/calmodulin-dependent kinase II activation. Biochem Biophys Res Commun. 2013 May 31;435(2):165-70. doi: 10.1016/j.bbrc.2013.04.092. Epub 2013 May 6.
Zuo ZF, Zhang Q, Liu XZ. Protective effects of curcumin on retinal Müller cell in early diabetic rats. Int J Ophthalmol. 2013 Aug 18;6(4):422-4. doi: 10.3980/j.issn.2222-3959.2013.04.02.