Table 2

Mean daily nutrient intakes estimates of the two food frequency questionnaires (FFQs) and twelve 24-hour recalls, and correlations between the two dietary methods ^a

24-hour recalls vs FFQ 1^†

24-hour recalls vs. FFQ 2^†

Repeat 24- hour recalls

FFQ 1

FFQ 2

Unadjusted

Energy adjusted

Unadjusted

Energy adjusted

r

r

r

r

Total Energy (kcal)

2324 ± 662

2541 ± 559*

2434 ± 644*

0.41

0.45

Total Carbohydrate (g)

327.9 ± 105.8

361.1 ± 105.9*

340.3 ± 113.2*

0.37

0.35

0.38

0.38

Protein (g)

101.7 ± 29.9

91.4 ± 27.5

103.1 ± 36.5

0.26

0.25*

0.33

0.31

Total Fat (g)

66.2 ± 22.8

64.8 ± 23.1

63.5 ± 32.8*

0.38

0.41

0.37

0.40

Total Saturated Fat (g)

29.9 ± 11.9

25.5 ± 10.4

28.6 ± 11.8

0.45

0.48

0.42

0.43

Total MUFA (g)

19.8 ± 10.7

19.3 ± 8.5

21.9 ± 12.6*

0.51

0.59

0.40

0.46

Total PUFA (g)

12.5 ± 5.1

11.8 ± 4.4

13.3 ± 6.3*

0.33

0.29

0.36

0.38

Linoleic acid

15.7 ± 12.4

16.7 ± 14.2

16.1 ± 14.1

0.43

0.41

0.47

0.44

Linolenic acid

0.69 ± 0.2

0.81 ± 0.3*

0.73 ± 0.3*

0.22^‡

0.35

0.38

0.43

Cholesterol (mg)

268.1 ± 106.1

259.7 ± 117.2

251.2 ± 114.0

0.52

0.53

0.47

0.41

Calcium (mg)

727 ± 218

782 ± 281

783 ± 341

0.44

0.50

0.45

0.45

Iron (g)

21.7 ± 9.3

20.0 ± 5.9

22.1 ± 9.8

0.43

0.42

0.44

0.43

Retinol (ug)

2171 ± 1680

2201 ± 1405

1860 ± 1143

0.21^‡

0.22

0.18^‡

0.17^‡

Beta-carotene (mg)

2271 ± 2420

2410 ± 2680*

1983 ± 2256**

0.35

0.33

0.34

0.34

Vitamin E (mg)

19.7 ± 7.5

15.4 ± 7.8**

16.8 ± 6.1**

0.21^‡

0.20^‡

0.23

0.23

Folate (g)

625.7 ± 242

634 ± 233

590 ± 185

0.56

0.59

0.42

0.45

Total dietary fiber (g)

28.6 ± 11.7

33.7 ± 11.8

30.7 ± 11.7

0.38

0.44

0.43

0.50

Alcohol (g)

2.8 ± 5.4

2.4 ± 2.7

2.6 ± 9.1

0.75

0.79

0.85

0.86

^† All variables were log-transformed before analysis.

^‡ Not significant; all correlations are significant to p≤ 0.001, unless indicated otherwise * p≤ 0.05.

^a Energy-adjusted correlations between dietary methods as suggested by Willett (1)

* p≤ 0.05; ** p≤ 0.001 - mean FFQ intake significantly different from repeat recalls.

Jackson et al. Nutrition Journal 2011 10:28   doi:10.1186/1475-2891-10-28