In the search for an effective Alzheimer’s treatment, vitamin E has been on scientists’ radar screens for a while. A new study by Research Assistant Professor of Pharmacology Domenico Praticò suggests that it’s all in the timing—and earlier is definitely better.
Since a major risk factor for Alzheimer’s is oxidative stress—when the oxygen we take into our bodies produces reactive substances that harm it—a powerful antioxidant like vitamin E would seem a natural choice for treating the degenerative disease. The data has been unclear, though.
A clinical trial six years ago found only mild improvements in patients with severe Alzheimer’s who took vitamin E. A recent epidemiological study indicated that people who took vitamin C and E supplements were less likely to develop Alzheimer’s in the first place. Praticò designed his study to find out what would happen if vitamin E treatment was started both early and late.
Using mice treated with a human Alzheimer’s gene, Praticò and his associates gave one group vitamin E at five months of age, before the characteristic Alzheimer’s plaques had started to form in the brain tissue. They started the other group at 14 months, when significant plaque had already been deposited. Each group was monitored for eight months and the outcomes were compared with controls that received no vitamin E. The young group showed a 50 percent reduction in the number of plaques as compared to the older mice.
Praticò was both surprised and not so surprised. “My prediction was that the early phase would work, so it was quite exciting to have that confirmed. But I had predicted that also in the late phases it would have done something significant. That it didn’t was for me quite surprising.”
The implications of the study are clear, said Praticò. “If you start to take it too late, it’s just a waste of time and money.” Once oxidative stress has triggered the beginning of the disease, and the plaque has been deposited on the brain, it becomes very hard to dissolve and, explained Praticò, the plaque actually stimulates more oxidative stress.
For people who have yet to experience Alzheimer symptoms, but are at risk for the disease, the message is more positive. Alzheimer’s is a condition that develops gradually, said Praticò. “It’s a very chronic, slow moving process and it doesn’t become clinically evident for at least five years, because the brain is able to compensate.” That means that people with risk factors for oxidative stress—such as diabetes, obesity, high cholesterol or a smoking habit—would do well to consider taking a vitamin E supplement.
“ Talk to your doctor first, and see if you have the risk factors,” said Praticò. “If you don’t have them, vitamin E won’t do anything. After the age of 60, I would recommend it to anybody, though, because there’s a normal decline in our capacity to defend against oxidants, and aging per se is a risk factor for Alzheimer’s.”
Originally published on April 1, 2004