A preliminary analysis of dietary habits in eleven countries suggests that a low-fat diet might reduce the risk of Alzheimer's. In countries with low-fat diets, such as China and Nigeria, the risk of developing Alzheimer's is 1% at age 65 compared to 5% in the US. A study in the Netherlands reported an association between dementia and diets high in total fat, saturated fat, and cholesterol. Saturated fats (found in animal products) and trans-fatty acids (found in fast foods and commercial baked goods) should be avoided. Some fats, however, such as omega-3 fatty acids, which are found in fish such as salmon, halibut, swordfish, and tuna are essential for the development of nervous system. These fatty acids also may help protect against mental decline in old age. Some reports have suggested that certain dietary antioxidants, such as vitamin C, E, and selenium may be protective against mental decline. Vitamin E is of particular interest. Most foods are not rich in this vitamin, but it can be obtained in vegetable oils (particularly wheat germ oil), sweet potatoes, avocados, nuts, sunflower seeds, and soy beans. According to a new study, eating plenty of fruits and vegetables may slow brain aging; they are recommended in any case for good health. Such foods also tend to be lower in calories -- which may be another protective feature. In another study on animals, restricting calories below normal (but above starvation levels) helped prevent age-related nerve degeneration. It should be pointed out, however, that in patients with existing Alzheimer's weight loss is a strong indicator of mental decline.

The early symptoms of Alzheimer's disease may be overlooked because they resemble signs of natural aging. These symptoms include forgetfulness, loss of concentration, unexplained weight loss, and motor problems, including mild difficulties in walking. In healthy individuals, similar symptoms can result from fatigue, grief or depression, illness, vision or hearing loss, the use of alcohol or certain medications, or simply the burden of too many details to remember at once. But when memory loss worsens, family and friends perceive that more serious problems exist (see Table, Differences between Normal Signs of Aging and Dementia, below). One clue to differentiating Alzheimer's from normal aging may be the patient's inability to understand the meaning of words. Accompanying sensory problems, such as hearing loss and a decline in reading ability, as well as general physical debility in newly diagnosed Alzheimer's patients indicate shorter survival time. A number of other disorders may be causing these extreme symptoms and must be ruled out before a diagnosis of Alzheimer's disease can be certain (see How Is Alzheimer's Disease Diagnosed?, below). About 20% of suspected Alzheimer's cases turn out to be some other disorder, half of which are potentially treatable or controllable. Strictly speaking, a definitive diagnosis of Alzheimer's can only be made at autopsy after death

Periodic memory lapses or

forgetfulness of part of an experience.

Misplacement of important items.

Occasional lapses in attention or concentration.

DEMENTIA

Memory and Concentration

Confusion about how to perform simple

tasks

Difficulty making routine decisions.

Confusion about month or season

Trouble with simple arithmetic problems

Increasing caution in movement.

Slower reaction times.

Movement/co-ordination / Dementia

Visibly impaired movement or coordination, including slowing of movements, halting gait, and reduced sense of balance.