With high doses of vitamin C, a number of adverse side effects have been encountered. The utilization of some nutrients and certain medicines gets affected.
Ascorbic acid significantly interacts with other nutrients and minerals in our body.
Supplements taken at a level above the upper tolerance level of 2 gms can interfere with copper metabolism.
Iron poisoning due to vitamin C
It is a well known fact that ascorbic acid enhances the absorption of iron in the gastrointestinal tract.
It helps in absorption of iron in the non-heme form by converting it into ferrous state.
Higher doses can induce more iron absorption.
In persons affected by haemochromatosis, a rare disorder, iron is accumulated in excess in the serum.
In such cases iron poisoning may occur in the affected persons if ascorbic acid is taken in excess.
In certain conditions, in people with glucose 6-phosphate dehydrogenase deficiency, excess of ascorbic acid can cause hemolysis (destruction of red blood cells).
In people with paroxysmal nocturnal hemoglobinuria, gout, cirrhosis or renal tubular acidosis, the conditions get worsened by acid loading due to overdoses.
Vitamin C side effects due to interaction with drugs
Higher doses of it increases the adverse reactions found associated with acetaminophen.
Antacids containing aluminum in forms like aluminum hydroxide can cause adverse reactions in the presence of excess ascorbic acid.
Another of the side effects is that the levels of the drug fluphenazine in the blood are reduced by excess supplements.
The adverse reactions of vitamin C are increased by barbiturates like phenobarbital, secobarbital or pentobarbital.
Overdose in the person with kidney insufficiency can cause kidney failure.
On the other side of the spectrum certain drugs and products have impact on the availability vitamin C.
Tobacco and nicotine products decrease the effects of vitamin C.
Aspirin reduces the availability of vitamin C whereas in higher levels, ascorbic acid reduces the level of aspirin.
Estrogen when taken orally may decrease ascorbic acid efficiency.
Ascorbic acid in large doses has been found to show reactions like interference with the warfarin blood thinning process.
Antibiotics like tetracycline, minocycline and doxycycline decrease the utilisation of the supplement. Considering the possibilities of vitamin C side effects it is advised not take the supplements above the upper tolerance level of 2 grams per day.
Side effects of vitamin C