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Validation Information: DietQ FFQ (Fatty acids)

Broadfield 2003

Measuring dietary fatty acid intake: validation of a food-frequency questionnaire against 7 d weighed records

There are few validated methods of measuring dietary fatty acid intake that are suitable for epidemiological research. The purpose of the present study was to develop and validate a food-frequency questionnaire (FFQ) developed to measure individual dietary fatty acid intakes against 7 d weighed dietary records, in a sample of thirty-one healthy adult volunteers. The FFQ was based on a previously validated questionnaire (DIETQ; Tinuviel Software, Warrington, Ches., UK), adapted to include greater detail on those foods from which the majority of dietary fatty acids are obtained. The FFQ and weighed records were analysed using food nutrient data from McCance and Widdowson's Food Composition Tables, supplemented with a food fatty acid content database (Foodbase, London, UK). Results from the two dietary assessment methods were compared by correlation coefficients and limits of agreement. The mean intake of individual fatty acids tended to be lower when assessed by FFQ. Correlation coefficients comparing unadjusted individual fatty acid intakes assessed by FFQ and weighed records ranged from 0·29 for 18:1n-9 to 0·71 for 20:4n-6. Adjusting for energy intake tended to increase the correlation coefficients between saturated fatty acids and decrease those between unsaturated fatty acids. In conclusion, this food-frequency method provides reliable estimates of dietary intake of many individual fatty acids for use in epidemiological studies.

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Validation Information

Year of Publication

Tool Information

Dietary Exposure Measured
Macronutrient, Food Groups
Tool Type
Food Frequency Questionnaire
Timeframe Tool Measures info
Portion Size Measures info
Each food item has a portion size assigned which uses common units or which uses average portion sizes from a previous study (Crawley, 1994).
Reporting Method info
Usual; Retrospective
Format info
Supplements Measured
Administration Method info

Study Information

Study Location
Nottingham, England
Associated Nutrient Database
McCance & Widdowson's The Composition of Foods, 5th edition
Comparator Validated Against
Weighed Food Diary


Sample Size
Age of Population

Mean(SD): 42.2(10.8) years

Other Notable Characteristics
Staff and research students from the Division of Respiratory Medicine.

Total number of nutrients validated: 4 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: 4
  • Micronutrients: 0
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 Fat (g) -1.5 28.1 0.38 (P) -57.7 54.7
Saturated Fat (g) -2.7 9.7 0.62 (P) -22.1 16.8
MUFA (g) -2.4 13.7 0.15 (P) -29.7 24.9
PUFA (g) -2 10.8 0.39 (P) -23.6 19.5

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.

Broadfield E, McKeever T, Fogarty A, Britton J. Measuring dietary fatty acid intake: validation of a food-frequency questionnaire against 7d weighed records. British Journal of Nutrition. 2003 Jul 1;90(01):215-20.