Reference intervals for vitamins B1, B2, E, D, retinol, beta-carotene, and folate in blood: usefulness of dietary selection criteria.

Reference intervals for normal concentrations in blood of vitamins B1, B2, E, D, retinol, beta-carotene, and folic acid were determined from a selected sample of people attending a Health Examination Center or being examined in occupational health services in France. This reference sample consisted of 362 men and women, ages 18 to 44 years, selected according to the main variation factors known for the vitamins studied: consumption of tobacco and alcohol, ponderal index (relating height and weight), use of drugs and oral contraceptives, and past history of surgical or medical treatment. Reference intervals were determined for each sex.