Vitamin E and melatonin help improve cognitive deficits in diabetic rats
A study published in the May 10, 2006 issue of the European Journal of Pharmacology found that diabetic rats given the antioxidants vitamin E or melatonin experienced less impairment of memory and learning compared to untreated diabetic rats. The finding provides support for the theory that oxidative stress is a culprit in cognitive impairment that occurs with diabetes.
Mehmet Tuzcu and Giyasettin Baydas of Firat University in Elazig, Turkey induced diabetes in 30 male rats. Ten animals received 10 milligrams per kilogram melatonin per day by injection, a second group received 100 milligrams per kilogram vitamin E, and a third group received a control substance for seven weeks. An additional ten animals in which diabetes was not induced were also injected with the control substance.
Diabetic rats who received vitamin E or melatonin showed significantly less impairment in memory and learning as assessed by a series of water maze tests compared to diabetic rats who did not receive the compounds. Lipid peroxidation in the brain’s cortex and hippocampus was significantly lower among rats treated with either compound compared to untreated diabetic rats. In addition, while levels of the antioxidant glutathione were lower in the diabetic rats who did not receive melatonin or vitamin E than in the brains of the nondiabetic controls, rats who received either compound had glutathione levels that were actually higher than the nondiabetic animals.
In their discussion of the findings, the authors suggest that vitamin E may lower oxidative damage to the synapses in the brain’s hippocampus caused by elevated blood sugar, thereby improving memory and learning deficits. In addition, previous research has suggested that melatonin’s ability to improve cognitive function is related to its antioxidant action. The reduction in brain glutathione occurring in the diabetic rats may elevate oxidative stress, and the prevention of this phenomenon by vitamin E and melatonin could help reverse its effects.
It is crucial that diabetics (and those predisposed to diabetes) understand the ways in which blood glucose causes damage and take active steps to interrupt these processes. The most notorious process is glycation, the same process that causes food to brown in an oven. Glycation (defined as sugar molecules reacting with proteins to produce nonfunctional structures in the body) is a key feature of diabetes-related complications because it compromises proteins throughout the body and is linked to nerve damage, heart attack, and blindness.
Oxidative stress is also central to the damage caused by diabetes. Diabetics suffer from high levels of free radicals that damage arteries throughout the body, from the eyes to the heart. Once again, it is important that diabetics understand their need for antioxidant therapy to help reduce oxidative stress and lower the risk of diabetic complications.
Vitamin E has been shown to significantly reduce the risk of developing type 2 diabetes (Montonen J et al 2004). One double-blind trial found a reduction in the risk of cardiac autonomic neuropathy, or damage to the nerves that supply the heart, which is a complication of diabetes (Manzella D et al 2001). Additional evidence documented benefits for diabetic peripheral neuropathy (Tutuncu NB et al 1998), blood sugar control (Kahler W et al 1993; Paolisso G et al 1993a,b, Paolisso G et al 1994), and cataract prevention (Paolisso G et al 1993a,b; Paolisso G et al 1994; Seddon JM et al 1994). In addition, vitamin E enhances sensitivity to insulin in type 2 diabetics (Paolisso G et al 1993a,b).
The brain generates a tremendous amount of free radicals as a part of its daily functioning. Some scientists believe that over the course of months and years, these free radicals may contribute to the impairment of healthy brain activity that occurs with aging.
Grape seed extract has demonstrated remarkable success in blocking the formation of senile plaques that severely damage the brains of those with dementia. As a result of these attributes, many researchers now consider grape seed extract to be an essential nutrient for maintaining brain health and vitality.
One of the most potent antioxidants available, grape seed extract possesses 20 times more free radical-fighting power than vitamin E and 50 times more than vitamin C. This remarkable antioxidant activity suggests that grape seed extract should become a part of any regimen to optimize brain health.
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