Special low protein foods (SLPF) are essential in the nutritional management of patients with phenylketonuria (PKU). The study objectives were to: 1) identify the number of SLPF available for use in eight European countries and Turkey and 2) analyse the nutritional composition of SLPF available in one of these countries. European Nutritionist Expert Panel on PKU (ENEP) members (Portugal, Spain, Belgium, Italy, Germany, Netherlands, UK, Denmark and Turkey) provided data on SPLF available in each country. The nutritional composition of Portuguese SLPF was compared with regular food products. The number of different SLPF available in each country varied widely with a median of 107 [ranging from 73 (Portugal) and 256 (Italy)]. Food analysis of SLPF available from a single country (Portugal) indicated that the mean phenylalanine content was higher in low protein baby cereals (mean 48 mg/100 g) and chocolate/energy bars/jelly (mean 41 mg/100 g). The energy content of different foods from a sub-group of SLPF (cookies) varied widely between 23 and 96 kcal/cookie. Low protein bread had a high fat content [mean 5.8 g/100 g (range 3.7 to 10)] compared with 1.6 g/100 g in regular bread. Seven of the 12 SLPF sub-groups (58 %) did not declare any vitamin content, and only 4 (33 %) identified a limited number of minerals. Whilst equal and free access to all SLPF is desirable, the widely variable nutritional composition requires careful nutritional knowledge of all products when prescribed for individual patients with PKU. There is a need for more specific nutritional standards for special low protein foods.

In PKU there is little data comparing the prevalence of overweight and obesity in different countries. The aim of this cross sectional study was to evaluate prevalence data from different PKU treatment centres in Europe and Turkey. In children, body mass index (BMI) and z scores and in adults BMI were calculated in 947 patients (783 children aged < 19 years; 164 adults aged ≥ 19 years) with PKU from centres in Europe and Turkey (Ankara, Birmingham, Brussels, Copenhagen, Groningen, Madrid, Munich and Porto). In adults with PKU, 83% of centres (n = 5/6) had less overweight than the general populations but 83% (n = 5/6) had a higher rate of female obesity. In childhood, all centres reported obesity rates within or similar to local population ranges in boys but in 57% (n = 4/7) of centres a higher rate of obesity in girls. The percentage of overweight and obesity increased with age. In PKU, it is clear from a number of treatment centres that women and girls with PKU appear particularly vulnerable to excess weight gain and it is important that female weight gain is closely monitored and individual strategies introduced to prevent excess weight gain. Overall, in PKU there is a need to understand better the food patterns and activity levels of patients.