Vitamin C

It was noted above (section 7.2.3.3) that vitamin C can act at the surface of cells or lipoproteins to reduce the tocopheroxyl radical back to tocopherol, forming the stable monodehydroascorbate radical. Vitamin C can also react with superoxide and hydroxyl radicals:

ascorbate + "O2- + H+ ^ H2O2 + monodehydroascorbate ascorbate + "OH + H+ ^ H2O + monodehydroascorbate

As shown in Figure 7.18, the resultant monodehydroascorbate can then undergo enzymic reduction back to ascorbate or a non-enzymic reaction between 2 mol of monodehydroascorbate to yield ascorbate and dehydroascorbate. Dehydroascorbate may then either be reduced to ascorbate or be oxidized to diketogulonate.

Although ascorbate has a protective role in the reactions shown above, it can also be a source of oxygen radicals, and hence potentially damaging:

ascorbate + O2 ^ "O2- + monodehydroascorbate ascorbate + Cu2+ ^ Cu+ + monodehydroascorbate

Figure 7.18 Metabolism of the monodehydroascorbate radical to non-radical products.

However, it is unlikely that high intakes of vitamin C will result in significant radical formation, as once intake rises above about 100—120 mg/day the vitamin is excreted quantitatively in the urine.

Supplements For Diabetics

Supplements For Diabetics

All you need is a proper diet of fresh fruits and vegetables and get plenty of exercise and you'll be fine. Ever heard those words from your doctor? If that's all heshe recommends then you're missing out an important ingredient for health that he's not telling you. Fact is that you can adhere to the strictest diet, watch everything you eat and get the exercise of amarathon runner and still come down with diabetic complications. Diet, exercise and standard drug treatments simply aren't enough to help keep your diabetes under control.

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