Low nickel diet

Dear Sir I found the paper by Pigatto et al. (1), describing the treatment of recurrent vesicular hand eczema in nickel-sensitive patients with a combination of disodium cromoglycate and a restrictive diet, most interesting. I would like to suggest, however, that the sub-population of 8 patients in the study, treated with a low nickel diet alone, could have achieved a greater reduction of nickel intake, had their restrictive diet been based on newer studies than those listed in this paper. The authors have apparently based the low nickel diet on a paper published in 1978 (2). The instructions for reducing nickel intake, given in that paper, are based on older studies of the nickel content of food items, and on analytical techniques available then, but hardly optimal today. Since the 1978 study, much more information regarding the nickel content of various foods has come to light. Certain food items not mentioned in Pigatto et al.'s diet instructions, such as soy meal, wheat bran, oatmeal, peanuts, hazelnuts, sunflower seeds, strong licorice and some dried fruits, consistently have a high nickel content, regardless of the nickel content of the soil in which they are grown ( 4-6). Just 50 g of peanuts, for example, would easily double the 24-h nickel intake, as would the same amount of soy meal in, for example, sausages or other prepared foods. The conclusion in the paper by Pigatto et al. (1990) that dietary restriction is not a very effective means of treating nickel allergic patients may be correct. This conclusion is, however, based on the treatment of only 8 patients, who did not follow a restrictive diet based on the currently available information regarding the nickel content of foods.