Corn Could Help Type 2 Diabetes, Kidney Complications
Corn (maize) is probably the most recognized food crop in the world, and its golden colored ears are a trademark. However, a purple corn variety found in Chile and Peru has been shown to possess some antidiabetic properties that may prove helpful in type 2 diabetes and associated kidney complications.
Purple corn has potent healing compounds
Purple corn is a maize variety that contains higher amounts of phytonutrients, especially anthocyanins and phenolics, than its golden and blue cousins. Anthocyanins have both antioxidant and anti-inflammatory properties and increasingly are being studied for their effect on various health challenges ranging from cancer to aging, heart disease, and diabetes.
In a new study from Hallym University in Korea, scientists report they have evidence that the anthocyanins found in purple corn have an ability to affect the development of diabetic nephropathy (diabetic kidney disease), a serious complication of diabetes that can lead to end-stage kidney disease. The evidence was gathered from two separate experiments.
In one experiment, the researchers evaluated the effect of purple corn anthocyanins on human cells while the other looked at the effect on kidney tissue in diabetic mice who were dosed with the phytonutrient for eight weeks. They found that:
- Exposure of the human cells to purple corn anthocyanins for six hours resulted in a reduction of adhesion of endothelial cells. This suggests the anthocyanins helped prevent the cells from sticking to glomeruli, structures that are responsible for filtering blood in the kidneys and thus play a significant role in the development of diabetic kidney disease
- Diabetic mice treated with purple corn anthocyanins showed several promising responses, including interruption of activity that may lead to cell adhesion and infiltration of cells responsible for diabetic kidney disease. Anthocyanins also inhibited levels of certain proteins in kidney tissue, suggesting they may help fight kidney inflammation.
Diabetic kidney disease
Diabetic kidney disease, also known as diabetic glomerulosclerosis, nephropathy, and diabetic nephropathy, develops when the nephrons (structures in the kidneys that filter blood and remove waste) become thick and scarred over time. Eventually the kidneys begin to leak protein (albumin) into the urine (proteinuria).
Not everyone who had diabetes develops diabetic kidney disease. According to the National Kidney Foundation, about 30% of people with type 1 and 10 to 40% of those with type 2 diabetes eventually develop kidney failure.
Risk factors for diabetic nephropathy include poor glucose management, high blood pressure, smoking, being African-American, Hispanic or American Indian, and development of type 1 diabetes before age 20. The earliest indication of kidney disease in diabetics is protein in the urine.
Purple corn and diabetes
Several previous studies have indicated that purple corn has potential in fighting diabetes. In 2009 in the Journal of Medicinal Food, scientists evaluated 10 Peruvian Andean grains for potential type 2 diabetes antihyperglycemia and antihypertension activity.
They found that purple corn had high antioxidant activity and the highest total phenolic (similar to anthocyanins) content of all the grains examined. In a subsequent study, scientists evaluated the effect of purple corn anthocyanins in both human cells and diabetic mice and concluded that "purple corn may be a potent therapeutic agent for the treatment of diabetes-associated glomerulosclerosis accompanying proteinuria and kidney filtration dysfunction."
Now the results of this latest study have provided scientists with more information on the potential use of purple corn anthocyanins in the prevention of kidney disease associated with diabetes. They note that supplementation with purple corn anthocyanins may be an important approach to help prevent kidney disease in type 2 diabetes.
Kang M-K et al. Purple corn anthocyanins inhibit diabetes-associated glomerular monocyte activation and macrophage infiltration. American Journal of Physiology--Renal Physiology 2012 Sept; doi:10.1152/ajprenal.00106.2012
Li J et al. Purple corn anthocyanins retard diabetes-associated glomerulosclerosis in mesangial cells and db/db mice. European Journal of Nutrition 2011 Nov 20
National Kidney Foundation
Ranilla LG et al. Evaluation of indigenous grains from the Peruvian Andean region for antidiabetes and antihypertension potential using in vitro methods. Journal of Medicinal Food 2009 Aug; 12(4): 704-11