By +Bob DeMarco
Alzheimer's Reading Room
Oxidative stress—damage to the cells from oxygen exposure—is thought to play a role in the development of Alzheimer’s disease, according to background information in the article. Experimental data suggest that antioxidants, nutrients that help repair this damage, may protect against the degeneration of nervous system cells.
“Although clinical trials have shown no benefit of antioxidant supplements for Alzheimer’s disease, the wider variety of antioxidants in food sources is not well studied relative to dementia risk; a few studies, with varying lengths of follow-up, have yielded inconsistent results,” the authors write.Elizabeth E. Devore, Sc.D., of Erasmus Medical Center, Rotterdam, the Netherlands, and colleagues assessed 5,395 participants 55 years and older who did not have dementia between 1990 and 1993.
Participants underwent a home interview and two clinical examinations at the beginning of the study, and provided dietary information through a two-step process involving a meal-based checklist and a food questionnaire.
The researchers focused on four antioxidants: vitamin E, vitamin C, beta carotene and flavonoids. The major food sources of vitamin E were margarine, sunflower oil, butter, cooking fat, soybean oil and mayonnaise; vitamin C came mainly from oranges, kiwi, grapefruit juice, grapefruit, cauliflower, red bell peppers and red cabbage; beta carotene, from carrots, spinach, vegetable soup, endive and tomato; and flavonoids from tea, onions, apples and carrots.
Over an average of 9.6 years of follow-up, 465 participants developed dementia; 365 of those were diagnosed with Alzheimer’s disease.
After adjusting for other potentially related factors, the one-third of individuals who consumed the most vitamin E (a median or midpoint of 18.5 milligrams per day) were 25 percent less likely to develop dementia than the one-third of participants who consumed the least (a median of 9 milligrams per day).
Dietary intake levels of vitamin C, beta carotene and flavonoids were not associated with dementia risk. Results were similar when only the participants diagnosed with Alzheimer’s disease were assessed.
“The brain is a site of high metabolic activity, which makes it vulnerable to oxidative damage, and slow accumulation of such damage over a lifetime may contribute to the development of dementia,” the authors write. “In particular, when beta-amyloid (a hallmark of pathologic Alzheimer’s disease) accumulates in the brain, an inflammatory response is likely evoked that produces nitric oxide radicals and downstream neurodegenerative effects. Vitamin E is a powerful fat-soluble antioxidant that may help to inhibit the pathogenesis of dementia.”Future studies are needed to evaluate dietary intake of antioxidants and dietary risks, including different points at which consuming more antioxidants might reduce risk, the authors conclude.
Editor’s Note: This study was supported in part by a grant from the Netherlands Organization for Scientific Research (Dr. Breteler) and by a training grant from the National Institutes of Health and by a U.S. Fulbright Fellowship to the Netherlands (Dr. Devore). Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.
- 100+ Good Reasons to Subscribe to the Alzheimer's Reading Room
- Alzheimer's CareGiving -- Insight and Advice
- Test Your Memory for Alzheimer's (5 Best Self Assessment Tests)
- Communicating in Alzheimer's World
- Worried About Alzheimer's Disease -- You Should Be
- What is Alzheimer's? What are the Eight Types of Dementia?
- Does the Combination of Aricept and Namenda Help Slow the Rate of Decline in Alzheimer's Patients
- Alzheimer's Disease Statistics
- Is it Really Alzheimer's or Something Else?
- Ten Symptoms of Early Stage Alzheimer's
- Ten Tips for Communicating with an Alzheimer’s Patient
Original content Bob DeMarco, the Alzheimer's Reading RoomBob DeMarco is the editor of the Alzheimer's Reading Room and an Alzheimer's caregiver. Bob has written more than 2,610 articles with more than 208,000 links on the Internet. Bob resides in Delray Beach, FL.