Nickel content of food and estimation of dietary intake

Nickel contents of foods are reviewed. A thorough knowledge of nickel in food is of new relevance. Among dermatologists it is a general opinion that flare of hand eczema can occur after per oral nickel exposure. The prevalence of nickel allergy in the Danish population is 10% for women and 2% for men. Nickel intake from the Danish diet is estimated as 150 microgram/person/day on average. Roots and vegetables, meal, grain and bread relatively supply the average diet with much nickel. Certain food items, e.g. cocoa and chocolate, soya beans, oatmeal, nuts and almonds, fresh and dried legumes, have very high nickel contents. Consumption of these items in larger amounts may increase the nickel intake to 900 micrograms/person/day or more. Within the range of 600-5,600 micrograms of nickel may provoke hand eczema, when given in single doses as nickel sulphate. An obvious question is thus whether nickel in the diet can cause flare of hand eczema. This should and can only be established by provocation studies with low-level nickel diets combined with a single food having a high nickel content.