Alzheimer's: Lower your risk of Alzheimers disease with these vitamins

What can I do to help prevent Alzheimer's disease (AD)?

That's one of the most common questions we receive here at HSI, through letters and e-mails.

As we've seen in recent e-alerts, sage and lemon balm may help reduce the severity of some early Alzheimer's symptoms. And research has also shown that epigallocatechin gallate (EGCG - a flavonoid found in green tea) may reduce the aggregation of beta-amyloid plaques that contribute to Alzheimer's.

But there's an even easier way to guard against Alzheimer's and other forms of dementia: Just make dietary choices that reduce homocysteine.

High homocysteine levels linked to cognitive decline
As we've seen in previous studies, elevated levels of the amino acid homocysteine have been linked with Alzheimer's disease and dementia. Considerable research has also demonstrated that foods and supplements rich in vitamins B6, B12, and folic acid help reduce homocysteine levels.

So, could these vitamins be effective in preventing AD?

Researchers from the Jean Mayer US Department of Agriculture (USDA) Human Nutrition Research Center on Ageing at Tufts University recruited more than 320 healthy older men from a Veterans Affairs study on ageing. At baseline, all of the men completed food-frequency questionnaires, and blood was drawn from each subject to measure B vitamins and homocysteine. Over the following three years the men took occasional tests to monitor cognitive function.

At the conclusion of the study, researchers found an association between high levels of homocysteine and a decline in recall memory. High levels of folate were significantly linked to verbal fluency. Men with elevated folate levels also had less decline in spatial copying; a drawing test that measures the brain's ability to understand and reproduce geometric figures.

Writing in the American Journal of Clinical Nutrition, the USDA authors concluded that, 'Low B vitamin and high homocysteine concentrations predict cognitive decline.'

Maintain mental ability with NAC and B complex
Vitamins B6, B12, and folate have been proven to help metabolise homocysteine. These nutrients are abundant in asparagus, lentils, chickpeas, most varieties of beans, and especially spinach and other leafy green vegetables. But many people don't absorb B vitamins well, so in addition to these food sources a good B-complex supplement is often required to lower homocysteine levels.

According to several studies, supplements of the antioxidant amino acid N-acetylcysteine (NAC) may also lower homocysteine levels.

A previous study showed how NAC improved cognitive function in patients with probable Alzheimer's disease. The 24-week study of 47 subjects revealed that those participants who took NAC showed improvement in nearly every outcome measure, without experiencing any negative side effects.

Vitamin combo helps lower Alzheimers risk
Once homocysteine levels are addressed, there are other nutrients that may offer further protection from Alzheimer's. In the e-alert 'Why not all studies are created equal' (27/4/05), I told you about two studies from Johns Hopkins University that show how two key vitamins may support cognitive function.

In the first study, nearly 580 subjects, aged 60 or older, were followed for more than seven years. A diet high in vitamin E (spinach, eggs, nuts, seeds, avocados, tomatoes, peaches and blackberries) was strongly associated with a significant reduction of Alzheimer's risk. Intake of dietary vitamin C was found to be somewhat useful in reducing AD risk, but less effective than vitamin E.

Nearly two years later, another Johns Hopkins team interviewed more than 4,700 subjects aged 65 or older. Supplement intake was assessed, as well as the prevalence of dementia and Alzheimer's disease, from 1995 to 1997, and again from 1998 to 2000. Evaluation of the data showed that in the first phase, those who took supplements of vitamins C and E combined had a 78 percent lower risk of AD. In the second phase, the percentage dropped to 64, but still indicated a significant level of protection.

In addition, Alzheimer's risk was even lower among subjects who took a vitamin E supplement along with a multivitamin that contained vitamin C.