Urinary excretion of vitamin B1, B2, B6, niacin,pantothenic acid,folate, and vitamin C correlates with dietary intakes of free-living elderly,female Japanese

We hypothesized that 24-hour urinary excretion of water-soluble vitamins might correlate with their intake in free-living Japanese elderly females aged 70 to 84 years. We performed a cross-sectional study composed of 37 healthy, elderly, Japanese females living freely. All foods and the corresponding weights consumed for 4 consecutive days were recorded accurately. A 24-hour urine sample was collected on the fourth day, and the urinary content of water-soluble vitamins was measured. The urinary levels of all vitamins, except for B₁₂ (r = 0.01; P = .936), were correlated positively with the mean intake over the recent 4 days (vitamin B₁: r = 0.62; P < .001; vitamin B₂: r = 0.57; P < .001; vitamin B₆: r = 0.37; P < .005; niacin: r = 0.54; P < .001; niacin equivalents: r = 0.54; P < .001; pantothenic acid: r = 0.59; P < .001; folate: r = 0.55; P = .001; and vitamin C: r = 0.53; P < .001). Mean estimated intakes of water-soluble vitamins calculated using urinary concentrations and recovery rates showed 96% to 107% of their 3-day mean intake, except for vitamin B₁₂ (65%). We conclude that urinary levels of water-soluble vitamins, except for B₁₂, reflected their recent intake in free-living Japanese elderly females and could be used as a measure of their intake during the previous few days both for group means and for individual rankings within a group.