Questions & Answers

Your article Vitamin E Does Not Prevent Declines in Memory and Cognitive Function in the October 2017 issue stated that Public Citizen’s Health Research Group has designated vitamin E as “Do Not Use.” But vitamin E is a component of the AREDS supplements recommended by the National Institutes of Health for age-related macular degeneration (AMD). Does your “Do Not Use” recommendation for vitamin E extend to AREDS supplements?

Our recommendation against using vitamin E supplements in general applies to taking vitamin E as a stand-alone dietary supplement. As we noted in our October article, eating a well-balanced diet should supply all the vitamin E that a healthy individual needs; taking excessive amounts of this vitamin may, among other things, interfere with blood clotting and increase the risk of death and prostate cancer.[1] However, we support the use of dietary supplements bearing the name AREDS or AREDS 2 that contain vitamin E in patients with moderate- or advanced-stage (but not early-stage) AMD. As discussed in our article Supplements for Age-Related Macular Degeneration in the August 2016 issue, two large, publicly funded clinical trials — known as the Age-Related Eye Disease Studies (AREDS and AREDS2) — demonstrated that a combination of high doses of zinc, vitamin E and other antioxidant supplements taken daily can slow the progression of AMD in patients with intermediate and advanced (but not early) disease.[2] The ingredients shown to be most effective and safest in the AREDS and AREDS2 trials were: vitamin C, 500 milligrams (mg); vitamin E, 400 international units; zinc, 25 or 80 mg; copper, 2 mg; lutein, 10 mg; and zeaxanthin, 2 mg. Other patients should avoid these AREDS supplements because they offer no proven benefits for early-stage AMD, cataracts or any other eye diseases, and they contain high-dose vitamins and minerals that may cause harmful side effects. See the article in our August 2016 issue for more details.

It is my understanding that there are several different forms of vitamin E. Could you clarify whether your article about vitamin E in the October 2017 issue addressed a specific form of vitamin E?

Your understanding is correct. Vitamin E is a family of compounds that includes four substances called tocopherols and four called tocotrienols.[3] Our article focused on the form of vitamin E known as alpha tocopherol, the primary biologically active form of vitamin E[4] and the most commonly used type of vitamin E dietary supplement. The major clinical trials discussed in our article tested the alpha tocopherol form of vitamin E.

In your article Drug for Treating Nighttime Urination Too Dangerous in the December 2017 issue, you had a “Do Not Use” recommendation for desmopressin nasal spray (NOCTIVA). My urologist has prescribed me a 0.2-milligram desmopressin tablet to take at bedtime to reduce frequent nighttime urination. Does your warning apply to the tablet form as well as the nasal spray (which seems to be the only form to which the article refers)?

Our “Do Not Use” recommendation for desmopressin only applies to the recently approved nasal spray form of the drug that is sold under the brand name Noctiva. However, it is important to note that the Food and Drug Administration (FDA) has not approved any other form of desmopressin, including the tablet form, to treat frequent nighttime urination in adults. Thus, the FDA has not determined that the tablet form of desmopressin is safe and effective for treating this condition. In addition, desmopressin tablets, like Noctiva, can cause potentially life-threatening hyponatremia (low blood sodium or salt levels). The risk of hyponatremia due to any dosage form of desmopressin is greater in elderly patients. We therefore advise against using any desmopressin-containing product to treat frequent nighttime urination. You should consult with your doctor before discontinuing any prescription medication.

References

[1] Vitamin E does not prevent declines in memory and cognitive function. October 2017. /newsletters/view/1157. Accessed November 6, 2017.

[2] Supplements for age-related macular degeneration. August 2016. /newsletters/view/1050. Accessed November 6, 2017.

[3] Ahsan H, Ahad A, Siddiqui WA. A review of characterization of tocotrienols from plant oils and foods. J Chem Biol. 2015;8(2):45–59.

[4] Pazirandeh S, Burns DL. Overview of vitamin E. UpToDate. October 3, 2016. https://www.uptodate.com/contents/overview-of-vitamin-e. Accessed December 21, 2017.