An approach to setting maxima in infant formulas.

It is clearly necessary to set upper limits for a nutrient in a formula where the nutrient can have a direct toxic effect (e.g., vitamin A) or can lead to a reduced margin of safety (e.g., high dietary renal solute load during gastroenteritis). In addition, there are plausible arguments for setting upper limits for any nutrient added during manufacture. Various expert groups have used different approaches in setting upper limits, particularly for fat and minerals. Evidence of clinical toxicity and various biochemical measurements have been commonly used to determine appropriate upper levels. Less use has been made of the empirical evidence provided by nutrient concentrations in commonly used foods, e.g., breast milk and cow's milk. Four "rules" for setting maxima are suggested: a) Use evidence of clinical toxicity or reduced margin of safety if available; b) Avoid nutrient concentrations that lead to biochemical values in body fluids or tissues very different from those seen in breast-fed babies; c) An upper limit should be set for even apparently harmless nutrients that are added during manufacture; and d) When a nutrient is added, its final concentration should not normally exceed that in breast or cow's milk, whichever is the greater. Using these "rules," suggested maxima for 33 nutrients are listed.