Validity of a short food frequency questionnaire for estimating nutrient intake in elderly people.

Nutrient intakes estimated using a short self-administered semi-quantitative food frequency questionnaire (FFQ) were compared with results obtained from five 2 d diet records using household measures in a group of fifty-three elderly people (mean age 70 years) in Dunedin, New Zealand in 1989. Mean intakes for most nutrients were less than 5% different between the two methods. Correlations between the nutrient intake values (excluding supplements) from the diet records and those from the FFQ ranged from 0.34 for Zn in women to more than 0.75 for protein, Zn and Ca in men. For most nutrients, at least 70% of the subjects when classified by the food records fell into the same quintile or into the within-one-quintile category when classified by the FFQ. These data indicate that in elderly subjects a simple self-administered semi-quantitative FFQ can provide very similar information (for both group and individual intakes for many nutrients) to that obtained from 10 d of careful diet recording.