Monday, December 04, 2006

Nutritional health: Alzheimer's

General Description
Alzheimers disease is a progressive neurodegenerative disorder which primarily affects brain structures involved in memory processes and motor skills. Alzheimers disease is the most common form of dementia, which generally refers to a progressive decline in mental function, memory and acquired intellectual skills.(1)

Pathologically, the brain is reduced in size (atrophy), especially in the frontal occcipital and temporal regions. Histologically, it is characterized by thickening, conglutination, and distortion of the intracellular neurofibrils (neurofibrillary tangles) and by plaques composed of granular or filamentous masses, found predominately in the nerve cells of the cerebral cortex, amygdala, and hippocampus. (1)

Major clinical criteria for the clinical diagnosis of probable Alzheimer's include:
1) deficits in two or more areas of cognition;
2) progressive worsening of memory;
3) absence of other medical or psychological disorders that could account for memory impairment; and
4) clear consciousness despite memory impairment.

The exact cause of Alzheimers is unknown. The etiology is complex and may involve several genes and possible environmental factors.(2)
Chronic exposure to aluminum has been suggested as a possible causative agent in Alzheimers. However, clinical evidence for this link is inconclusive.(3)
Oxidative stress may play a role in the pathogenesis of neuron degeneration and death in Alzheimers (4,5) An increase in free radical production has been demonstrated in Alzheimers disease brain tissue.
In particular, iron has been shown to be a significant component of senile plaques in Alzheimers disease (6) and may contribute to the disease process by initiating lipid peroxidation, leading to membrane damage and ultimately cell death.(7)

At Risk
Alzheimer's disease is obviously related to age, - that is, the older you get the more likely you are to develop Alzheimer's disease or dementia. For instance, the prevalence of dementia is roughly 3% for individuals aged 65 to 74, whereas it is 18.7% for individuals between the ages of 75 and 84 and nearly 50% for those over age 85. In addition, there is evidence to suggest that genetic factors may play a part in some forms of AD.
Clinical manifestations of mental deterioration, memory loss, confusion, and disorientation may begin in late mid-life (>45 years old). Death usually results in about 5 to 10 years after diagnosis.

Prevention and Management

Nutrition influences:
Nutritional support is important in the treatment of Alzheimers.(2)
In patients with moderately severe impairment from Alzheimer's disease, treatment with alpha-tocopherol (vitamin E) or selegiline slows the progression of disease.(8)
There is an association between Alzheimers and low serum cobalamin (vitamin B12) levels.(9)
Deficiency of choline, an important component of membrane phospholipids and the neurotransmitter acetylcholine, may play a role in the etiology of Alzheimers(10)