dose tested. Hansen et al. (2003) found a LOAEL of approximately 32 mg of hazel nut protein, although it is not clear whether this was the lowest dose tested.
Fish. Hebling et al. (1999) reported a LOAEL of 50 mg for catfish protein.
Wheat. Unpublished data described in Moneret-Vautrin and Kanny (2004) show that
83% of wheat allergic children reacted to less than 2 g of wheat flour while only 18% of wheat allergic adults responded at this level. Unpublished data described in Moneret- Vautrin (2004) on wheat flour challenges using 32 children and 32 adults with wheat allergy, reported a LOAEL of 1.8 mg protein for allergic children (the lowest tested dose) and 52.8 mg protein for allergic adults. Scibilia et al. (2006) reported that 2 of 13
responders reacted to the lowest dose of wheat flour tested (100 mg of a mix of bread and
durum flour, approximately 15 mg protein) in DBPCFCs. In total, 31% of the patients who reacted did so to challenge doses less than or equal to 240 mg of wheat protein.
J. Food Treatments to Reduce Allergenicity The best example of food products that are processed to render them less allergenic are hydrolyzed infant formulas derived from cow’s milk proteins (i.e., casein and whey). Enzymatic hydrolysis of these proteins has been shown to significantly reduce the levels of both total and allergenic (e.g., β-lactoglobulin in whey) protein (Host and Halken, 2004). The degree of protein reduction depends on the method of hydrolysis. There is ample clinical evidence to suggest that both partially hydrolyzed formulas (PHF) and extensively hydrolyzed formulas (EHF) have reduced allergenicity in comparison to intact milk formulas (Amer. Acad. Ped., 2000; Host and Halken, 2004). Furthermore, there is preliminary evidence that the use of thse hydrolyzed formulas may also delay or prevent the development of cow’s milk allergy (CMA) in high-risk infants (Host and Halken, 2004).
Both PHF and EHF contain varying amounts of residual protein, including allergenic proteins, which can be detected using either in vitro or in vivo methods (Giampietro et al., 2001; Docena et al., 2002), that have been shown to retain immunologic activity. Both PHF and EHF can cause allergic reactions, including anaphylaxis, in sensitive infants (Saylor and Bahna, 1991; Schwartz and Amonette, 1991; Tarim et al., 1994; Ammar et al., 1999; Giampietro et al., 2001; Host and Halken, 2004). In general, the higher the level of residual protein, the higher the risk for an allergic response. Although the level of residual protein tends to be higher in PHF, the degree of hydrolysis cannot always be used as a predictor of the degree of allergenicity. Hydrolysis methods are not standardized, and formulas undergoing similar treatments may vary considerably in their residual protein levels. Additional processing, such as heat treatment and ultrafiltration, may further reduce residual protein levels in certain products (Host and Halken, 2004).
In 1989, the American Academy of Pediatrics (AAP) concluded that a formula could be considered “hypoallergenic” if challenge studies showed, at a minimum, 95% confidence that 90% of allergic infants would not react adversely to the formula (AAP, 1989). Since this time, a number of DBPCFC studies using various infant formula preparations have been performed in infants with CMA (Sampson et al., 1991; Sampson et al., 1992b;
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