|Methods for the Evaluation of the Impact of Food and Nutrition Programmes (UNU, 1984, 287 p.)|
|4. Measuring impact using laboratory methodologies|
Prolonged dietary inadequacy alters the biochemical milieu of the body, and consequently enzymatic activities. in advance of the appearance of clinical symptoms and signs. Laboratory measurements of the nutrient adequacy of body fluids or tissues, therefore, can provide objective, specific, and sensitive indicators of nutriture.
These measurements, judiciously selected for some nutrients, can provide subclinical information useful in evaluating the nutritional impact of nutrition interventions.
Depending on the specific nutrient in question, adequacy may be measured biochemically by:
Which laboratory approach is appropriate for measuring adequacy for a particular nutrient will depend on an understanding of its basic biochemical role, the distribution among body compartments during periods of dietary lack and sufficiency, and how this distribution is influenced by short and long-term changes in the physiological environment, e.g.. acute and chronic infections, and hormonal imbalances and variations.