Table 5.

Biomarker and food group relationship (as derived from Foodbook24 and food diary).

Biomarkersa		Nutrient or food groupb	Foodbook24 correlation coefficient	Diary correlation coefficient
			(r value)c	(r value)c
Concentration biomarkers			(n=28)	(n=34)
	Plasma ascorbic acid (µM)	Fruit and veg (g/d)	0.421	0.505
	Plasma total carotenoids (µmol/L)	Fruit and veg (g/d)	0.315e	0.671
	Plasma omega-3 index	Fish (g/d)	0.468	0.769
	Plasma ascorbic acid (µM)	Vitamin C (mg/d)	0.518	0.605
Recovery biomarkers			(n=34)	(n=33)
	Urinary urea (mmol/d)	Protein (g/d)	0.645	0.824
	Urinary potassium (mmol/d)	Potassium (mg/d)	0.542	0.269e
	Urinary sodium (mmol/d)d	Sodium (mg/d)	0.56	0.476

^aPlasma and urinary biomarkers identified from fasted blood samples and 24-hour urine collections (respectively) collected from participants directly after recording intake using either dietary assessment methods.

^bThe data refer to nutrient and food group intakes recorded using Foodbook24 and the semi-weighed food diary.

^cSpearman correlation coefficient.

^dSodium excretion measures were corrected to account for 90% excretion of all sodium consumed (28).

^eNot statistically significant correlations (P<.05).