Effect of cooking loss in the assessment of vitamin intake for epidemiological data in Japan

Eur J Clin Nutr. 2011 Apr;65(4):546-52. doi: 10.1038/ejcn.2011.10. Epub 2011 Feb 23.


Background/objectives: The effect of cooking loss on vitamin intake is an important consideration in dietary and epidemiological studies in Japanese. However, because few published food values have considered cooking effect, allowing for cooking loss in the assessment of vitamin intake in Japan has been difficult.

Subjects/methods: Seven-day dietary records and a fasting blood sample were collected from 102 men and 113 women in August of 1994 or 1995. Vitamin intake were estimated using two food databases, one composed of raw food only and the second of cooked food. Estimates were compared with blood levels.

Results: Water-soluble vitamin intake using a food database including cooked food was lower than intakes estimated using a database composed of raw food only, except for pantothenic acid and vitamin B(12) intake. In particular, vitamin B(1) intake was 18.9% lower in men and 16.8% lower in women. However, when subjects were classified into the same and adjacent categories by joint classification by quintiles, appreciable change in ranking of a subject was not observed. Furthermore, the relationship between vitamin intake and biomarker did not improve when intake was calculated using a food database including cooked food.

Conclusion: Although the effect of cooking loss on absolute values is not negligible, this might not significantly impact the ranking of subject intake estimations of vitamin intake in epidemiological studies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers
  • Carotenoids / blood
  • Cooking*
  • Diet Records
  • Energy Intake
  • Feeding Behavior*
  • Female
  • Humans
  • Japan / epidemiology
  • Male
  • Middle Aged
  • Nutrition Assessment*
  • Nutritional Physiological Phenomena*
  • Vitamins / blood*


  • Biomarkers
  • Vitamins
  • Carotenoids