Vitamin E is a very important antioxidant for the body's lipids, protecting all structures from heavy metals, free radicals and other toxic substances. It inhibits, through its antioxidant power, the oxidation of lipids in cell membranes, bloodstream lipids, and cholesterol. The oxidation of bloodstream lipids and LDL (low-density lipoproteins) is a risk factor for atherosclerosis. This vitamin elevates HDL, increases the breakdown rate of LDL and fibrin (a protein involved in coagulation), inhibits platelet aggregation and helps re-establish a normal heart rhythm (regulates cardiac muscle response to calcium). The properties of vitamin E also benefit the arteries, veins and capillaries. Research highlights therapeutic and preventive benefits with vitamin E supplementation in numerous conditions such as atherosclerosis, cerebrovascular disease, Reynaud's disease (disorder that causes vasoconstriction in the extremities), vasculitis, intermittent claudication, hot flashes, and edema. Due to its ability to prevent the oxidation of cell membrane lipids, vitamin E has been shown to improve insulin sensitivity and glucose tolerance. Vitamin E supplementation has also been shown to improve the HDL/LDL ratio in diabetic patients. Elevated blood sugar levels predispose individuals to increased bloodstream lipids and increase the risk of cardiovascular disease. The high concentrations of lipids found in the brain and peripheral nerves make the nervous system susceptible to oxidative stress. Many neurological and brain disorders are influenced by oxidative stress, and vitamin E deficiency is often present. Some studies have shown therapeutic benefits with vitamin E supplementation in conditions such as Alzheimer's, Parkinson's, tardive dyskinesia (involuntary repetitive movements), and degenerative neuromuscular disorders. Scientific evidence also demonstrates benefits at the level of skin problems such as ulcers, seborrheic dermatitis, acne (when combined with selenium), systemic lupus erythematosus, and prevention of sunburns (when combined with vitamin C). In addition to this overall protection, vitamin E also acts on immune function, protecting the thymus, white blood cells, and the entire system, especially during viral processes. Additionally, as a protective, antioxidant agent, it has a beneficial role in preventing many degenerative conditions such as cancer and cardiovascular disease.