Insight Into Turmeric Benefits in Diabetes and CVD

Examining how curcumin and other bioactive compounds in turmeric lower blood glucose and may be beneficial for type 2 diabetes and cardiovascular disease. 

Turmeric is a natural herb that comes from the rhizome of the Curcuma longa plant. Turmeric has been used for many years worldwide as a treatment for metabolic and cardiovascular disease. In the U.S, turmeric is one of the most sold herbal products, sold as a dietary supplement and nutraceutical. Turmeric can be divided into two major groups, curcuminoids, and essential oils. These two groups display bioactive properties that benefit cardiovascular diseases and diabetes. Curcumin is the principal and abundant curcuminoid in turmeric and has been extensively studied. However, other curcuminoids have not been studied as extensively. This review looks into the complex composition of turmeric and its bioactive constituents that have metabolic health benefits. 

Turmeric comprises moisture, carbohydrate, protein, fat, minerals, and trace amounts of vitamins. Turmeric oil is a group of essential oils that consist of more than 250 diverse terpenoids. These essential oils obtained from turmeric rhizome consist mainly of terpenoid. The main terpenoids in the essential oils include sesquiterpenoids, monoterpenoids, and norsesquiterpenoids. The curcuminoids consist of more than 50 structurally related compounds. The three main structures present in turmeric are curcumin, demethoxycurcumin, and bisdemethoxycurcumin.  

Through different mechanisms of action, curcumin and other bioactive compounds lower blood glucose by the upregulation of insulin, enhanced insulin sensitivity, and lower cellular glucose uptake. Curcumin’s antidiabetic and hypoglycemic effects involve the pancreatic β- cells. Curcumin activates the PI3K/Akt/GLUT2 signaling pathway, which is required to regulate cellular glucose uptake and metabolism. Curcumin reduces glucose uptake in adipocytes and hepatocytes by inhibiting translocation of GLUT4 from the cytosol to plasma. GLUT1 is also directly inhibited by curcumin, thus lowering glucose uptake in GLUT1 expressing cells. Oxidative stress induced by high glucose levels can be attenuated by curcumin. 

Turmeric also inhibits two of the main enzymes involved in glucose digestion. These enzymes are α-amylase and α-glucosidase. Regardless of the form turmeric was tested in, it showed a relatively more potent effect than the standard antidiabetic drug acarbose on these enzymes. 

In genetically diabetic mice, turmeric extract suppressed diet-induced increases in blood glucose levels. In alloxan-induced diabetic mice, hydroethanolic extract of turmeric effectively controlled blood glucose levels. In other studies conducted in mice, curcumin improved glucose tolerance by stimulating glucagon-like peptide-1 and incretin from enteroendocrine L cells. In addition, turmeric extract significantly increased peroxisome proliferator-activated receptor gamma (PPAR-γ) ligand-binding activity in mice. This effect may be beneficial in reducing complications associated with type II diabetes. 

Turmeric, curcumin, and curcuminoids effectively improve relevant anthropometric and biochemical metabolic parameters in patients with metabolic syndrome. Turmeric has improved C-reactive protein levels, body mass index (BMI), serum low-density lipoprotein cholesterol, and the percent body fat in patients with metabolic syndrome morbidities. Turmeric and the related curcuminoids can actively prevent the development of type II diabetes by alleviating metabolic syndrome. Turmeric also improves metabolic syndrome in patients with existing type II diabetes. In a double-blind, randomized control trial, patients with type II diabetes were supplemented with turmeric rhizome powder, a curcumin capsule consisting of curcuminoids and turmeric oil, or a curcuminoid-piperine combination over eight to 12 weeks. These patients had positive changes in lipid profiles and lowered body weight and BMI. According to a systematic review and meta-analysis of randomized control trials, curcuminoid preparations effectively lower BMI and body weight in patients with type II diabetes. Studies have shown that nano-curcumin with enhanced bioavailability can improve glycemic indices in a patient with type 2 diabetes 

There is considerable evidence from studies conducted in vitro, in vivo, and in human clinical trials that indicate that turmeric and its bioactive components can protect against cardiovascular disease, especially curcumin. Its cardioprotective properties have been attributed to curcumin’s antioxidants and anti-inflammatory effects that regulate signaling pathways. Turmeric, curcumin, and curcuminoids effectively prevent cardiovascular disease in healthy and patients who have underlying cardiovascular disease risk. 

Turmeric and its associated bioactive constituents, from multiple studies, has shown it has benefits that lower blood glucose levels, lower body weight, improve serum lipid profiles, and improve inflammatory conditions in type 2 diabetes patients. 

Practice Pearls: 

• Studies have shown that turmeric can affect many signaling pathways in the body. 
• Turmeric has possible benefits in patients with diabetes and cardiovascular diseases. 
• Turmeric has many bioactive constituents that require further research to determine their benefits 

Zhang, Huiying Amelie, and David D Kitts. “Turmeric and its bioactive constituents trigger cell signaling mechanisms that protect against diabetes and cardiovascular diseases.” Molecular and cellular biochemistry vol. 476,10 (2021): 3785-3814. doi:10.1007/s11010-021-04201-6 

Author: Jerrine Fletcher, Fourth Year Doctor of Pharmacy Candidate, Florida A&M University College of Pharmacy and Pharmaceutical Sciences, Institute of Public Health