Alzheimer's disease There is positive news; exercise and lifestyle modifications decrease risk

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Clarifying progress in Alzheimer's disease

There is positive news; exercise and lifestyle modifications decrease risk

By Dunaief, M.D.

September 23, 2010 | 03:59 AM

There has been a flood of recent press about steps forward and backward in

treating Alzheimer's disease. Recently, scientists discovered that it may be

possible to diagnose early-stage Alzheimer's using two different techniques. One

is the PET scan, which uses radioactive dye while scanning the brain for

beta-amyloid plaques, a biomarker present in the disease. The other is a lumbar

puncture, which uses a needle aspiration of the spinal fluid to determine if two

biomarkers that relate to the disease are present, b(eta)-amyloid plaques and

tau proteins.

There is a raging debate regarding the value of early testing for Alzheimer's.

Many neurologists are excited by this new advancement in testing. In fact, the

National Institute on Aging has recommended the use of biomarkers for early

detection of the disease, possibly providing a decade or more lead time before

the appearance of degenerative symptoms, which typically occur after age 60.

I think anyone who either has a family history of the disease, has been

diagnosed with mild cognitive impairment, has the ApoE4 gene or is ready to

enroll in clinical trials or to make lifestyle changes is an especially good

candidate for early testing.

If you consider testing, there are a few things you should know. First, the

tests themselves have a low risk of side effects, which must be considered.

Second, the cause of Alzheimer's disease eludes investigators. We know that tau

proteins and b-amyloid plaques are biomarkers that may signify the disease.

However, they are not specific to Alzheimer's. In fact, one third of the elderly

have b-amyloid plaques in the brain even though they may not have Alzheimer's.

Lastly, there is no current drug treatment for Alzheimer's which addresses the

cause, stops the progression and/or reverses the disease. Medicines in the

pipeline have not fared well, thus far. The latest failure is Eli Lilly's drug,

semagacestat, used to reduce b-amyloid plaques. In two trials, it showed

worsening in cognitive function and in activities of daily living and an

increase in skin cancer compared to placebo.

So, why test?

The physiology of Alzheimer's involves the degeneration or breakdown of the

neurons that receive signals. Recently, study results suggest that neurons may

regenerate, but even if it this is the case, the magnitude of the effect would

probably be way too little to have any impact on Alzheimer's. Therefore,

reversing the disease is very difficult, but preventing or slowing its progress

is much more likely. Thus, the sooner a potential diagnosis is made, the better.

We also know that the presence of other diseases may speed the progression of

Alzheimer's. Most of these diseases are treatable with lifestyle modifications.

These same modifications may also benefit those with Alzheimer's alone. Results

from a large cohort study show that nutrition, using the Mediterranean-type

diet, seems to help prevent Alzheimer's disease. In this study, published in the

Archives of Neurology in April, 2010, there were 2148 participants from northern

Manhattan with a median age of 78 at baseline. The results showed an impressive

38 percent reduction in the development of Alzheimer's over a 3.9 year duration.

Positive effects were seen with increased levels of such items as cruciferous

vegetables, green leafy vegetables, nuts and fish, whereas negative effects were

seen with saturated fats, red meats, butter and high-fat dairy.

In a case-control study (Arch. Neurol. 2010;67:80-86), moderate exercise

decreased the risk of MCI, a precursor to Alzheimer's, substantially in

participants. Those who were in midlife (50 to 65) experienced slightly better

results than those who were older at baseline.

There are those in the medical community who would criticize the above two

trials, since neither is a randomized controlled trial, which is considered the

gold standard to prove effectiveness. These arguments have merit. Clinical

trials would be ideal, but for now, we have preliminary data from large trials

that show potent results with diet and exercise. The definitive results will be

a while in coming.

The moral of the story is becoming apparent; we need more awareness of and

emphasis on lifestyle modification, both in the media and medical community.

These two trials demonstrate that it is never too late to make beneficial

changes. Testing that motivates people to do so is a good thing.

Dr. Dunaief is a lifestyle medicine physician focusing on the integration of

medicine, nutrition and fitness.