The pilot study will include 30 children and adolescents with heterozygous Familial Hypercholesterolemia. All children and adolescents will be recruited from the Paediatrics Outpatient Department of the Division of Clinical Nutrition and Metabolism at the Vienna University Hospital. Furthermore, children of patients with heart stroke, patients from other paediatrics and patients from other children hospitals will be recruited. Inclusion criteria: To be eligible the study participants will have to be aged between 4 and 18 years, do not regularly eat soy food and do not have a protein allergy. The participants are recruited by their familial history and/or their cholesterol levels (elevated over 130 mg/dl and total cholesterol elevated over 200 mg/dl) according to American Academy of Paediatrics criteria. Furthermore they should keep a 7-day nutrition record at the beginning of study. Exclusion criteria: Patients younger than 4 years and older than 18 years, children who are extremely underweight according to Kromeyer Hausschild´s criteria. Children and adolescents with mental disability and with simultaneous medication and protein allergy. Complete physical information will be done and a thorough medical history will be taken in all participants. Physical examination and blood sampling will be performed in the outpatient clinic setting as done routinely.