Can antioxidants decrease the effectiveness of certain cholesterol lowering medications?

Date:

27-Aug-2001

Source

Arteriosclerosis, Thrombosis, and Vascular Biology

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Article

Statin drugs are considered by some to be the most effective way to manage high cholesterol. They are prescribed to millions of people for heart disease, stroke, and cholesterol management. Until recently, they were thought to be free from side effects and while some side effects have been identified, statins still appear to be the first line of defense in the heart and stroke category from a prescription drug perspective.
Just as millions of people are using statin drugs, millions are also taking antioxidants as a preventative measure in their own health care program. Antioxidants are known to scavenge the free radicals that can do damage to cells in the body and have been implicated in disease and the aging process. Even a basic multivitamin formula contains antioxidants such as vitamins A,C, E, and the mineral selenium. Other antioxidants include alpha lipoic acid, Co Q10, and melatonin. With such a large number of nutrients that fit into the antioxidant category, antioxidant use is quite high.
Until recently, there was no real concern over the concurrent use of statins and antioxidants. However, a recent study has claimed that there are interactions between the two. In this study, one hundred and fifty three patients with coronary artery disease, high LDL-cholesterol, and low HDL-cholesterol had their plasma cholesterol, triglyceride, LDL-C, and HDL-C levels evaluated for 12 months. Each patient was randomly assigned to one of four groups; simvastatin plus niacin, antioxidants (vitamins E and C, ß-carotene, and selenium), simvastatin plus niacin, and antioxidants, or placebo.
The antioxidant only group and the placebo group had minimal changes in the measured lipid levels. Both the groups utilizing the simvastatin plus niacin had significant reductions in plasma cholesterol, triglyceride, and LDL-C. Where the two groups differed was in the desired increases in HDL-cholesterol. Increases in HDL-C and HDL2-C were higher in the simvastatin plus niacin group than in the simvastatin plus niacin and antioxidants group. Also, only the simvastatin plus niacin group displayed an increase in both apolipoprotein (apo) A-I in HDL particles containing apo A-I but not A-II [Lp(A-I)] and their particle size.
It appeared to the authors that the only variable that could have had this affect was the addition of the antioxidant. The favorable response found with the statin and niacin combination was not there when the antioxidant was added. The authors concluded, “this unexpected adverse interaction between antioxidants and lipid therapy may have important implications for the management of CAD."1
It is probable that additional studies will be conducted to verify these results and to further determine the mechanism that determined this outcome.

References

1. Cheung MC. Antioxidant Supplements Block the Response of HDL to Simvastatin-Niacin Therapy in Patients With Coronary Artery Disease and Low HDL. Arteriosclerosis, Thrombosis, and Vascular Biology. Aug 2001;21:1320.