Brain Preservers How can you protect your brain from developing dementia? Let me count the ways… "Oxidative stress contributes to brain aging." That observation leads off a new long-term intervention study that appears in a recent issue of the Archives of Internal Medicine. STUDY PROFILE - A team of Harvard researchers recruited nearly 6,000 subjects from two different phases of the Physicians' Health Study
- All of the subjects were over the age of 65
- Subjects received either placebo or 50 mg of beta-carotene every other day
- About 4,000 subjects participated in the early phase of the study, and all of these subjects received either placebo or the beta-carotene supplement for an average of 18 years
- Subjects in the later phase of the study were recruited in 1998
- Subjects were interviewed to determine general cognition, verbal memory, and category fluency
- Subjects in the later phase who took beta-carotene performed no better in the interviews than placebo subjects
- Subjects in the longer early phase who took beta-carotene had significantly higher global scores compared to placebo, and significantly higher scores on verbal memory compared to placebo
Amyloid plaque deposits in the brain, which are associated with Alzheimer's disease, may be prompted in part by oxidative stress. The researchers believe beta-carotene supplementation may have helped alleviate that stress. If beta-carotene does play a key role in the prevention of dementia and Alzheimer's disease (AD), you can be sure it doesn't work alone. So let's take a look at a few excerpts from past e-Alerts that examined various nutrients that help keep cognitive function healthy and bright. Try the catch of the day. A 2002 Canadian study found that Alzheimer's patients and elderly patients with various types of dementia all had lower levels of docosahexaenoic acid (DHA - an omega-3 fatty acid) than subjects with normal cognitive function. And in a follow up study, researchers analyzed ten years of data taken from more than 1,100 elderly men and women. Results showed that those with high levels of DHA had nearly 50 percent reduced risk of developing AD. A generous intake of niacin has been linked to a reduced risk of cognitive decline. In a 2006 study that followed more than 800 subjects over the age of 65 for five years, researchers found that subjects with the highest dietary intake of niacin had an 80 percent reduced risk of cognitive decline compared to those with the lowest niacin intake. The best sources of niacin are in high-protein foods such as beef liver, salmon, chicken, and peanuts. In 2005, USDA researchers monitored blood samples, food intake, and cognitive function in more than 320 older men for three years. Their conclusion: "Low B vitamin and high homocysteine concentrations predict cognitive decline." As we've seen in previous studies, folate is very helpful in reducing homocysteine levels. Among this study's findings was the note that high folate levels in the blood were significantly linked to verbal fluency. And finally, two old standbys - vitamins C and E - may help beta-carotene manage the oxidative stress that promotes amyloid plaque buildup. In 2006, a Johns Hopkins team interviewed more than 4,700 subjects aged 65 or older. About six years of supplement intake was assessed, as well as the incidence of dementia and Alzheimer's disease. Results showed that those who took supplements of vitamins C and E combined had a significantly lower risk of developing Alzheimer's. In addition, AD risk was even lower among subjects who took a vitamin E supplement along with a multivitamin that contained vitamin C. Source:
"A Randomized Trial of Beta Carotene Supplementation and Cognitive Function in Men" Archives of Internal Medicine, Vol. 167, No. 20, 11/12/07, archinte.ama-assn.org | 
