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Validation Information: Short FFQ (Folate)

Pufulete 2002

Validation of a short food frequency questionnaire to assess folate intake

A short quantitative food frequency questionnaire (FFQ) to assess folate intake was developed and validated against a 7-d weighed food intake record (7d-WR) and biochemical indices of folate status. Thirty-six men and women completed the self-administered FFQ on two occasions a month apart, kept a 7d-WR and gave two fasting blood samples at the beginning and end of the study for measuring serum and erythrocyte folate, respectively. Mean folate intakes were similar by repeat FFQ and correlated strongly (r 0·77 and r 0·72, P<0·001, for men and women, respectively). All other comparisons were done using the results of the FFQ administered on the first occasion. Men reported similar folate intakes on the FFQ and 7d-WR, but women reported greater intakes on the FFQ compared with the 7d-WR (P<0·05). There was a statistically significant correlation (partial, controlling for gender) between folate intakes reported by FFQ and 7d-WR (r 0·53, P<0·01). Folate intakes estimated by FFQ correlated significantly with serum (r 0·47, P<0·01), but not erythrocyte folate (r 0·25, P>0·05); the strength of the association was greater in men than in women. Validity coefficients estimated using the method of triads were higher for the FFQ than for the 7d-WR when serum folate was used as the biomarker. Overall, these results suggest that this short FFQ is a useful method for assessing folate intake, particularly in men.

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Validation Information

Year of Publication

Tool Information

Dietary Exposure Measured
Micronutrient, Food Groups
Tool Type
Food Frequency Questionnaire
Timeframe Tool Measures info
1 Year
Portion Size Measures info
Photographic Atlas of Food Portion Sizes. Participants were also prompted to write down weights and volumes of frequently consumed packaged items.
Reporting Method info
Usual; Retrospective
Format info
Supplements Measured
Administration Method info

Study Information

Study Location
London, England
Associated Nutrient Database
Integrated Dietary Analysis (IDA) software, version 2.03 (IDA Publications Ltd, 1997). Based on McCance and Widdowson’s The Composition of Foods, 5th edition and supplements.
Comparator Validated Against
Biomarkers, Weighed Food Diary


Sample Size
36 (Both, Weighed Food Diary), 36 (Both, Biomarkers), 36 (Male, Weighed Food Diary), 36 (Female, Weighed Food Diary), 36 (Male, Biomarkers), 36 (Female, Biomarkers)
Age of Population

Range: 22-65 years

Mean: 36 years (Male); 37 years (Female)

Both, Male Only, Female Only
Other Notable Characteristics
Participants were recruited from the staff and students from King's College London and through publicity in sports centres, libraries and other public venues.

Total number of nutrients validated: 1 info

Not all of the nutrients validated in the validation studies are included in the table below, as statistical data was only selected to be displayed for a number of nutrients, this included:

  • Energy
  • Fat
  • Saturated Fat
  • Mono-unsaturated Fat
  • Poly-unsaturated Fat
  • Carbohydrates
  • Protein
  • Sugar
  • Non‐starch polysaccharides(NSP)
  • Sodium
  • Calcium
  • Iron
  • Zinc
  • Retinol
  • Folate
  • Folic Acid
  • Vitamin B12
  • Vitamin C
  • Fruit & Vegetables
  • Urinary Nitrogen

To find information on the other validated nutrients please read the validation study.

  • Macronutrients: 0
  • Micronutrients: 1
Comparator Lifestage Sex Nutrient Measured info Mean Difference Standard Deviation info Correlation Coefficient info Cohen's Kappa Coefficient Percentage Agreement Percentage Agreement Categories info Lower Limits of Agreement Upper Limits of Agreement
Weighed Food Diary Adults Both Folate (µg) 50 27 -3 103
Biomarkers Adults Both Folate (µg) 0.47 (P)
Weighed Food Diary Adults Male Only Folate (µg) -3 46 0.69 (P) 69 3 -93 87
Weighed Food Diary Adults Female Only Folate (µg) 94 30 0.30 (P) 45 3 35 152
Biomarkers Adults Male Only Folate (µg) 0.55 (P)
Biomarkers Adults Female Only Folate (µg) 0.36 (P)

Some results have been calculated using statistical techniques based on the published data.

For further information on statistical terms click on Statistical tests used in validation studies

All correlations coefficients in the table are unadjusted unless stated otherwise. For adjusted correlation coefficients and other statistical methods used in the study e.g. paired t-tests, please read the validation articles.

  • # Adjusted
  • † Energy adjusted.
  • ‡ For loge-transformed, energy-adjusted nutrient intakes.
  • ^ Adjacent included.
  • ᵟ Participants provided identical responses.
  • (w) = Weighted.

Pufulete M, Emery PW, Nelson M, Sanders TA. Validation of a short food frequency questionnaire to assess folate intake. British Journal of Nutrition. 2002 Apr 1;87(04):383-90.