OTHER REACTIONS

V. OTHER REACTIONS

Hypersensitivity reactions to food additives in organs other than the skin or respiratory tract are rare and poorly documented. The consideration that adverse reactions may easily affect the site of entrance of the food or additive suggests that hypersensitivity reactions in the gastrointestinal tract would be common. Nausea, diarrhea, pain, abdominal disten- sion, and vomiting have been observed in some patients who have experienced respiratory or skin symptoms provoked by azo dyes or sulfites. However, virtually nothing is known about the incidence of gastrointestinal manifestation associated with additives when other symptoms are absent. Farah et al. (1985) showed convincingly that only a small number of patients with gastrointestinal symptoms have verifiable specific food intolerance and the greater number have symptoms attributable to psychogenic causes. It is more than probable that the same conclusions also apply to food additives.

A. Hyperactivity in Children

Overreactivity, with concentration and learning difficulties, may be present in 1–5% of young children (Lambert et al., 1978). Feingold (1973) claimed that hyperactivity of chil- dren is associated with the ingestion of salicylates and crossreacting food additives. He reported that 30–50% of hyperactive children in his practice had complete remission of symptoms on a salicylate- and additive-free diet. However, these observations have not been confirmed in double-blind studies. The U.S. National Institutes of Health (NIH, 1983) evaluated the evidence and concluded that it does not support the Feingold hypothesis, although it does not exclude the possibility that hyperactive behavior could be attributable to food dyes in a minority of cases. Weiss et al. (1980) observed deterioration of behavior in 2 of 22 hyperactive children challenged with a mixture of food dyes after 3 months on an additive-free diet. A doubtful positive response to diet was achieved in 15 hyperkinetic children in the study of Conners et al. (1976), but no diet effect was found by Harley et al. (1978) in 36 school-age hyperactive boys.

Rowe and Rowe (1994) made a 21-day double-blind placebo-controlled repeated- measures study in 34 children, 23 of whom were suspected to react to artificial food colors along with 11 uncertain reactors and 20 control children. Tatrazine (1, 2, 5, 10, 20, and

50 mg) or placebo were given randomly each morning. Altogether 24 out of the 24 children reacted to tartrazine, and a dose-response effect was noticed in 19 of 23 suspected reactors, in 3 of 11 uncertain reactors, and in 2 of 20 control children. Irritability, restlessness, and sleep disturbances were the most common symptoms.

Pollock and Warner (1990) recruited 39 children whose behavior was observed by their parents to improve on a food additive–free diet and to deteriorate with dietary lapses. Placebo-controlled double-blind peroral challenges were performed with the following colorants: 50 mg of tartrazine, 25 mg of Sunset Yellow, 25 mg of carmoisine, and 25 mg of amaranth. Only 19 children completed the study. In only two instances, the parents were able to notice changes in their childrens’ behavior. The mean daily Conners behavior scores were significantly (p ⬍ 0.01) higher when the children were taking the food colors

B. Other Symptoms Attributed to Allergies

Headaches and migraines have often been claimed to be provoked by food allergies, but the objective evidence is sparse. The role of food additives is not known. Tartrazine has been shown to cause pain and swelling in the knee joints in an asthmatic patient (Wraith, 1980). Joint and muscular pains, arthralgias, and even arthritis provoked by food and food additives have been reported (Rowe and Rowe, 1972) but have not been confirmed by controlled studies.

C. Psychological Factors

According to several studies it is obvious that many, if not most, of the adverse reactions to food and food additives are in fact psychosomatic. Pearson et al. (1983) found that objectively confirmable hypersensitivity could be found in only 4 of 23 adults who claimed to have food allergy. All four subjects were atopic. Lum (1985) reviewed hyperventilation and pseudoallergic reactions. He wrote:

Following an address to a meeting of food intolerance sufferers, more than 50% of the audi- ence recognized that many of their presumed ‘‘intolerance’’ symptoms tallied with those of overbreathing. A patient who experiences faintness, dizziness, nausea or migraine in a warm crowded and stuffy restaurant or at dinner party may consider that an allergy to food is in- volved. Repetition of the reaction in similar circumstances is likely to set up a conditioned reflex response.

Pearson and Rix (1985) published an extensive review on allergomimetic reactions and pseudo food allergy. Lessof (1983), in his review of food intolerance and allergy, stated that the most common cause of an aversion to food is psychological.

The importance of double-blind challenging was studied by Jewett et al. (1990). Eighteen patients were tested with various foods by double-blind test. Positive responses to active substances were seen in 16 of 60 (27%) instances, while the corresponding num- ber for placebo was 44 of 180 (24%). The difference was statistically not significant.

The methodological aspects for clinical studies of adverse reactions to foods and food additives have been discussed by many groups. One can get a good view on the problems in such investigations in the paper of Metcalfe and Sampson (1990).