Using diet to modulate Alzheimer’s disease

Researchers at the University of Washington School of Medicine, in Seattle, compared the effects of a high–saturated fat/high–glycemic index diet with a low–saturated fat/low–glycemic index diet on markers of Alzheimer disease and cognition in adults with mild cognitive impairment.

First, the details.

• 49 older adults (20 healthy and 29 with amnestic mild cognitive impairment) were assigned to a treatment group for 4 weeks.
  • HIGH diet (fat, 45% [saturated fat, less than 25%]; carbohydrates, 35% – 40% [glycemic index, greater than 70]; and protein, 15% – 20%)
  • LOW diet (fat, 25%; [saturated fat, less 7%]; carbohydrates, 55% – 60% [glycemic index, less than 55]; and protein, 15% – 20%)
• Cognitive tests, an oral glucose tolerance test, and lumbar puncture were conducted at before and during the fourth week of the diet.
• Cerebrospinal fluid concentrations of beta-amyloid (Abeta42 and Abeta40), tau protein, insulin, F2-isoprostanes, and apolipoprotein E, plasma lipids and insulin, and measures of cognition were measured.

And, the results.

• For the group with amnestic mild cognitive impairment:
  • The LOW diet increased CSF Abeta42 concentrations, contrary to lowered CSF Abeta42 typically observed in Alzheimer disease.
• In healthy adults:
  • The LOW diet decreased CSF Abeta42.
  • The HIGH diet increased CSF Abeta42.
• CSF apolipoprotein E concentration:
  • Increased by the LOW diet and decreased by the HIGH diet for both groups.
• More results
  • The CSF insulin concentration increased with the LOW diet in the amnestic mild cognitive impairment group.
  • The HIGH diet lowered the CSF insulin concentration for healthy adults.
  • The HIGH diet increased and the LOW diet decreased plasma lipids, insulin, and CSF F2-isoprostane (marker for oxidative stress) concentrations.
  • Delayed visual memory improved for both groups after completing 4 weeks of the LOW diet.

The bottom line?

The authors concluded, “Diet may be a powerful environmental factor that modulates Alzheimer disease risk through its effects on central nervous system concentrations of Abeta42, lipoproteins, oxidative stress, and insulin.

More about Abeta42 is here.

6/17/11 22:24 JR