Prevention of infection in the general population and the institutionalized

Is nutritional therapy of value in preventing infectious diseases in the developed world? There is a large body of evidence that supports the thesis that insufficient intake of dietary protein adversely affects the immune system and predisposes the malnourished to infectious diseases [3-5]. This inadequate protein intake is usually coupled with reduced intake of calories and is referred to as protein-calorie malnutrition (PCM).

Protein

Since there are no prospective studies in which protein intake is manipulated in order to assess infection risk in non-hospitalized people, indirect studies must be evaluated. The use of serum albumin as an indicator of protein intake is fraught with problems as chronic illnesses in themselves may prevent adequate protein intake and may inhibit the synthesis of albumin [6].

Preoperative albumin levels have been shown to correlate with the postoperative risk for pneumonia, urinary tract infections and wound infections in a large Veterans Administration study [7]. This study did not deal directly with nutrition, however. A more relevant study looked at 1,023 acute trauma patients admitted to a Baltimore hospital. Since these patients were acutely ill due to a non-medical condition, their albumin levels were more likely to reflect previous nutritional status rather than previous medical illness. There was a 48% incidence of infection in those admitted with a serum albumin of less than 2.6 gms/dL and a 28% incidence in those with an albumin of 2.6 gms/dL or above (p < 0.001). The infections were predominately respiratory and urinary in nature [8].

This evidence indirectly supports adequate protein intake as a factor in preventing infections after trauma.