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Validation Information: FFQ (6 months old)

Marriot 2008

What do babies eat? Evaluation of a food frequency questionnaire to assess the diets of infants aged 6 months

Objective: To evaluate the relative validity of a food frequency questionnaire (FFQ) for assessing nutrient intakes in 6-month-old infants.

Design and setting: The FFQ was developed to assess the diets of infants born to women in the Southampton Women's Survey (SWS), a population-based survey of young women and their offspring. The energy and nutrient intakes obtained from an interviewer-administered FFQ were compared with those obtained from a 4-day weighed diary.

Subjects and methods: A sub-sample of 50 infants aged 6 months from the SWS had their diets assessed by both methods. The FFQ recorded the frequencies and amounts of milks, baby foods, regular foods and drinks consumed by the infants over the previous seven days. The diaries recorded the weights of all foods and drinks consumed by the infants on four separate days within 15 days following FFQ completion.

Results: Spearman rank correlation coefficients for intakes of energy, macronutrients and 18 micronutrients, determined by the two methods, ranged from r = 0.39 to 0.86; adjustment for energy intake tended to increase the correlation coefficients, range ra= 0.55 to 0.89. Bland-Altman statistics showed that mean differences between methods were in the range of -12.5% to +12.5% except for vitamin B12 (-18.9 %).

Conclusion: Although there were differences in absolute energy and nutrient intakes between methods, Spearman rank correlation coefficients indicated reasonable agreement in the ranking of intakes. The interviewer-administered FFQ is a useful tool for assessing energy and nutrient intakes of healthy infants aged about 6 months.

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Validation Information

Year of Publication

Tool Information

Dietary Exposure Measured
Full Nutrient
Tool Type
Food Frequency Questionnaire
Timeframe Tool Measures info
1 Week
Portion Size Measures info
Household measures and food models. Breast milk intake was estimated from the reported duration of breast-feeding at each feed.
Reporting Method info
Usual; Retrospective
Format info
Supplements Measured
Administration Method info
by-proxy: parents interviewed by a trained research nurse.

Study Information

Study Location
Southampton, England
Associated Nutrient Database
Nutritional composition information for infant formulas and commercial baby foods was obtained from manufacturers and/or by calculation from ingredients; and for non-baby products was taken from McCance & Widdowson's The Composition of Foods, 5th edition and supplements
Comparator Validated Against
Weighed Food Diary


Sample Size
Infants and toddlers
Age of Population

Range: 6 months

Mean: 6 months ±2 weeks

Other Notable Characteristics
The infants were the offspring of the women that were recruited in the Southampton Women Survey (SWS). The infants were born between 1998 and 2003.

Total number of nutrients validated: 23 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.

  • Energy
  • Macronutrients: 4
  • Micronutrients: 18
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 Infants and toddlers Both Energy (kcal) 6% 0.41 (S) -40% 52%
Energy (kJ) 6% 0.41 (S) -40% 52%
Protein (g) 1% 0.51 (S) -48% 49%
Fat (g) 4% 0.39 (S) -47% 54%
Carbohydrates (g) 9% 0.51 (S) -37% 55%
Total Sugars (g) 9% 0.55 (S) -36% 54%
Sodium (mg) -12.2% 0.60 (S) -87% 62%
Calcium (mg) 3.4% 0.62 (S) -58% 65%
Iron (mg) 2% 0.75 (S) -59% 63%
Zinc (mg) 7.4% 0.69 (S) -44% 59%
Retinol (µg) 10% 0.44 (S) -49% 69%
Folic Acid (µg) 9.1% 0.68 (S) -42% 60%
Vitamin B12 (µg) -18.9% 0.75 (S) -135% 97%
Vitamin C (mg) 11.2% 0.67 (S) -45% 67%

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.

Marriott LD, Robinson SM, Poole J, Borland SE, Godfrey KM, Law CM, Inskip HM. What do babies eat? Evaluation of a food frequency questionnaire to assess the diets of infants aged 6 months. Public health nutrition. 2008 Jul 1;11(07):751-6.