"One of the issues in doing a good study is understanding the nutritional status of your participants when you start and how the nutrient treatment changes it," Ho said. "Giving supplements or foods to a person who already has a normal nutritional status of that nutrient may be very different than if the person is deficient."
Complicating the issue, she said, is that elderly people in general may not absorb or process many nutrients as well as younger adults, and because of genetic differences they many have different biological responses to the same level of a nutrient. Knowing what they ate gives, at best, only a partial picture of what their nutritional status actually is. And it also assumes that people, including those with beginning dementia, will always remember with accuracy what their diet actually has been when questioned about 124 food items in an interview that can last up to two hours.
In this study, the scientists recruited 38 elderly participants, half with documented memory deficit and the other half cognitively intact. They compared the reliability of the nutrient biomarkers to food questionnaires administered twice over one month.
The questionnaire was able to determine some nutrient levels, but only in the group with good memory. The reliability of the nutrient biomarkers depended on the nutrient of interest, but overall performed very well.
"Now that we have a reliable blood test for assessing nutritional status, we can begin to study nutrient biomarkers in combination, their interactive features, and how they collectively may influence chronic diseases, including risk for Alzheimer's disease and dementia," Bowman said.
Such approaches could lead to more effective nutritional therapies in the future to promote cognitive health, he said.
|Contact: Emily Ho|
Oregon State University