Diabetics need to take an antioxidant supplement even though their blood sugar levels are well controlled. A newly discovered phenomenon in diabetics called "metabolic memory" ensures that damaging free radical release and oxidative stress continue in spite of effective treatment. The only way they can counter this is by taking an antioxidant supplement.

Antioxidant Treatment of Diabetes by Metabolic Memory Control.

For a number of years we have known that diabetic patients suffer from free radical overload and oxidative stress. New scientific evidence shows that oxidative stress is the underlying cause of the blood vessel damage so characteristic of diabetes. Most of the important complications of diabetes are caused by diseased blood vessels. High blood pressure, poor circulation, kidney disease and nerve damage are primarily the result of damage to both small and large blood vessels in diabetic patients.  

Research shows that the damage done to blood vessels is caused by the action of free radicals on the endothelium (or lining) of the blood vessels.
Even though it is a layer only one cell deep, the endothelium is a very important part of the blood vessel. It has many vital functions; not only does it control the dilatation and constriction of blood vessels but it also regulates the release of various hormones and the formation of clots in the arteries. Endothelial dysfunction leads to arterial constriction atherosclerosis and irreversible arterial damage thereby increasing the risk of heart attack, stroke, peripheral arterial disease, kidney failure and other problems.

Hyperglycemia (high blood sugar) is the cause of free radical overload and, until recently, it was thought that once the blood sugar was under control the harmful effects of oxidative stress would be halted. However this has been shown not to be the case and a mechanism called “metabolic memory” has been described that accounts for this phenomenon. It appears as though, during the periods when an individual’s blood sugar is not controlled, proteins are glycated (attached to a glucose molecule). These glycated proteins retain a ‘memory’ which compels them to continue to send out stress signals. This stress signaling maintains the production of excess free radicals even after treatment has returned the blood sugar levels to normal. Unless countered by dietary antioxidants, the persistent release of free radicals maintains the unhealthy state of oxidative stress.

A recent clinical trial has shown conclusively that those insulin dependent diabetics who took antioxidants in addition to insulin reduced oxidative stress considerably compared to those who were using insulin without an antioxidant.
This and other studies have also discovered further interesting information regarding the type of antioxidants used to treat oxidative stress in diabetics. Vitamin E ( considered a powerful antioxidant) was found to be of no use at all in this context and vitamin C, although effective, did not completely control oxidative stress – even in those diabetics who’s blood sugar levels were very well controlled and did not have any other conditions that may have caused oxidative stress.

This observation should not come as too much of a surprise when we appreciate the fact that there are many different types of free radicals and that no individual antioxidant can access all parts of the cell or neutralize all free radical species.

The research tells us two important things. Firstly, that diabetics need to ensure that they are very aggressive in controlling their blood sugar levels at all times. In addition, by far the majority of people are diagnosed with diabetes long after the disease process has started. This means that they were probably under oxidative stress for months or years prior to receiving treatment and that the harmful “metabolic memory” has become well entrenched in their cellular proteins. Even if the diabetics, once they receive treatment, then go on to achieve effective blood sugar levels, the metabolic memory will continue to stimulate free radical release and sustain the damaging oxidative stress.

Accumulated research to date tells us that not only do all diabetics need to take adequate amounts and variety of antioxidants but non-diabetics need to do so too. Apart from having regular check-ups to see whether you have diabetes or not, you can protect yourself against arterial damage by eating a diet high in antioxidant-rich foods. However if you are at risk of diabetes or any other disease associated with oxidative stress you should take an antioxidant supplement too.
Spices have the highest antioxidant activity of all food groups (American Journal of Clinical Nutrition 2006) and a spice-based antioxidant supplement provides over 100 effective antioxidant compounds.

References:

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