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WIDE-RANGING EFFECTS: BONE, KIDNEY, EYE, BRAIN DISEASES 219diseases_ " 9, 50 This means that people with cognitive impairment have
about a tenfold risk of Alzheimer's.
Not only does cognitive impairment often lead to more serious de-
mentia, it is also associated with cardiovascular disease, 5 1- 53 strokes" and
adult-onset Type 2 diabetes. 55, 56 All of these diseases cluster in the same
populations, oftentimes in the same people. This clustering means that
they share some of the same risk factors. Hypertension (high blood
pressure) is one factoyS1, 57, 58 ; another is high blood cholesterol. 53 Both
of these, of course, can be controlled by diet.
A third risk factor is the amount of those nasty free radicals, which
wreak havoc on brain function in our later years. Because free radical
damage is so important to the process of cognitive dysfunction and
dementia, researchers believe that consuming dietary antioxidants can
shield our brains from this damage, as in other diseases. Animal-based
foods lack antioxidant shields and tend to activate free radical produc-
tion and cell damage, while plant-based foods, with their abundant an-
tioxidants, tend to prevent such damage. It's the same dietary cause and
effect that we saw with macular degeneration.
Of course, genetics plays a role, and specific genes have been identi-
fied that may increase the risk of cognitive decline. 52 But environmental
factors also playa key role, most probably the dominant one.
In a recent study, it was found that Japanese American men living
in Hawaii had a higher rate of Alzheimer's disease than Japanese living
in Japan.^59 Another study found that native Africans had significantly
lower rates of dementia and Alzheimer's than African Americans in In-
diana.^60 Both of these findings clearly support the idea that environment
plays an important role in cognitive disorders.
Worldwide, the prevalence patterns of cognitive disorders appear to
be similar to other Western diseases. Rates of Alzheimer's are low in less
developed areas.6 1 A recent study compared Alzheimer's rates to dietary
variables across eleven different countries and found that populations
with a high fat intake and low cereal and grain intake had higher rates
of the disease. 62 , 63
We seem to be on to something. Clearly, diet has an important voice
in determining how well we think in our later years. But what exactly
is good for us?
With regard to the more mild cognitive impairment condition, recent
research has shown that high vitamin E levels in the blood are related
to less memory 10ss.64 Less memory loss also is associated with higher