Newer laboratory methods for assessing nutriture of selected B-complex vitamins.

This review is limited to progress in the development of new or improved laboratory procedures to assess the nutriture of thiamin, riboflavin, niacin, vitamin B6, and folic acid. There has been marked progress in this area for the other vitamins as well. The increased availability of radioassay techniques and HPLC methodologies that have application in nutrition assessment is significant. However, for a number of the vitamins, there is still a need for additional methods that provide functionally interpretable preclinical information and give accurate assessment of body reserves of the nutrient. Often the guides used to interpret the information obtained are tentative and require validation or revision. This situation is further complicated by the frequent lack of suitable reference standards for quality controls and interlaboratory validation.