Subjective and objective nutritional assessment methods: what do they really assess?

Objective and subjective methods are used to assess nutritional status. They are used as diagnostic, prognostic and response tools. It is still controversial which of them is more suitable for each situation and what they are really assessing. The most recent findings about these methods will be discussed in this review.

Malnutrition still has a high prevalence all over the world. Anthropometric measurements are best useful to assess chronic malnutrition, and albumin and other visceral protein should no longer be considered as nutritional markers, but inflammatory response markers. Subjective global assessment enables comparison among different populations, and its scored version may be useful in other clinical situations besides cancer. Functional methods and bioelectrical impedance analysis may become possible to identify malnutrition in an early stage. Nitrogen balance seems to be the only way to assess the response to nutritional interventions.

Malnutrition should be understood as a continuum. Nutritional assessment should not be an expensive and time-consuming process, and simple methods such as subjective global assessment may be enough to identify those patients who need nutritional intervention. Future studies may show which method is more suitable to evaluate the response to this treatment.