Preventive Interventions for Alzheimer's Disease: Positive Results for Vitamins C and E

Although several medications are available for Alzheimer's disease (AD), most confer only mild to modest symptomatic benefit for a few months to 1-2 years. Even when treated with these drugs, patients' AD still continues to progress.

Patients who develop AD usually experience a period of progressive cognitive decline before their AD diagnoses. In fact, people who have mild cognitive impairment (MCI) or cognitive impairment without meeting dementia criteria (cognitive impairment, not dementia [CIND]) develop AD more often than people who do not. For this reason, many people consider cognitive decline as a step between normal aging and AD. AD is widespread, and researchers continue to look for interventions that could delay its onset.

CIND has 3 different subtypes—psychiatric origin, vascular, and other specific neurological disorders. Researchers believe that intervening before CIND develops or early in its course could possibly delay AD onset. Medications that work early in CIND might thus be preventive for AD. Antioxidants seem to be reasonable candidates for this role.

The Annals of Pharmacotherapy published a study that examines the association between antioxidant vitamin supplement use and AD risk. The study suggests that vitamin E and vitamin C supplementation may reduce risk of CIND, AD, or all-cause dementia.

The researchers used data from the Canadian Study of Health and Aging (1991-2002) covering 5269 people aged 65 years and older. The study assessed participants 3 times over 11 years. Participants self-reported vitamin C and E supplementation. Patients who used vitamin C and/or E supplements were significantly less likely to develop CIND, AD, or any type of dementia.

When the researchers broadened the definition of vitamin C and/or E exposure to include exposure to multivitamins, patients also had reduced CIND risk.

The study indicates that antioxidant vitamins reduce neuronal damage and death caused by oxidative stress, which alters dementia's pathogenesis.

Although the results suggest positive preventive benefits of vitamin C and E supplements, the researchers concluded that further investigations are needed to determine the value of vitamin C and E as a primary preventive strategy for AD.

Reference

Basambombo LL, Carmichael PH, Côté S, Laurin D. Use of Vitamin E and C Supplements for the Prevention of Cognitive Decline. Ann Pharmacother. 2017Feb;51(2):118-124. doi: 10.1177/1060028016673072.