Effects of Soy Protein on Cholesterol Levels in Children Affected With Familial Hypercholesterolemia
Condition: Heterozygous Familial Hypercholesterolemia
MeSH terms: Hyperlipoproteinemia Type II; Hypercholesterolemia
Study type: Interventional

Summary: 
      Familial hypercholesterolemia (FH) is an inheritable, autosomal dominant disorder leading to
      pathologically increased levels of low-density-lipoprotein cholesterol (LDL-C). Dietary
      treatment remains an important tool in the management of affected children even after the
      decision for the initiation of pharmacotherapy is made. However, little evidence is available
      on the beneficial effects of diets low in saturated fat and cholesterol and diets enriched
      with soy in children affected with FH. Based on these previous findings we hypothesize that
      the LDL-C lowering effect of a fat-modified diet could be further increased by the addition
      of soy-protein in children affected with HeFH.
    

Detailed description: 
      This study is a prospective randomized controlled trial. The enrolled subjects were recruited
      from the outpatient clinic for disorders of metabolism of the Medical University of Vienna.
      Subjects were either allocated into a group treated with a dietary regimen high in
      unsaturated fats, low in saturated fats and enriched with soy-protein ("soy group") or a
      group treated with a diet high in unsaturated fats and low in saturated fats ("control
      group") alone at random. All subjects had been instructed to adhere to a fat-modified diet as
      described below prior to enrolment into the study as part of their routine treatment. Prior
      to being considered for inclusion in the study all subjects had to undergo nutritional
      protocoling using 24h dietary recall protocols, which were completed by their legal
      guardians, for 7 days. This was done to confirm adherence to the routine dietary treatment.
      Furthermore, all patients had been screened for metabolic diseases other than FH as part of
      their initial routine assessment in our specialised centre.

      Subjects in both groups had been instructed to achieve specific daily maximum intakes in
      total fat (≤ 30% of total energy intake), saturated fatty acids (≤10% of total fat intake)
      and cholesterol (≤ 300 mg). Furthermore the participating families had been trained to
      replace as many visible fat sources as possible with rapeseed oil due to its favorable
      composition of polyunsaturated fatty acids.24 Subjects allocated to the soy group and their
      families were additionally instructed to consume at least 0.25 g of soy protein per kg
      bodyweight per day and were provided with recipes and practical advice on how to achieve this
      goal. Example provided: a child with a bodyweight of 30kg would have to consume the
      equivalent of approx. 50g of Tofu per day to meet the treatment target. This dosage had been
      reported as effective for LDL-C reduction in children in a previous, non-controlled study.10

      Further appointments with an experienced dietitian were made after enrolment for both
      treatment groups, totalling 7 training sessions (60 minutes each) over the course of the
      first 7 weeks of the trial. This was done to identify possible issues with the practical
      implementation of especially the soy-enriched diet.

      Patients were asked to provide weekly urine samples and blood was drawn immediately after
      enrolment, week 7 and week 13, respectively. The urine- and plasma samples were immediately
      frozen and later analysed for their isoflavone content. Isoflavone levels were assessed at
      baseline to verify that the respective patients did not consume soy products prior to the
      trial. All enrolled subjects had to participate for 13 weeks or were excluded from the
      statistical evaluation (per protocol analysis). If relevant levels of isoflavones were
      detected in either urine or plasma of subjects in the Control-group the subjects were to be
      excluded from any further statistical evaluation.

      The study was approved by the Ethics Committee of the Medical University of Vienna. Informed
      consent from all participating subjects and their legal guardians was obtained prior to their
      enrolment in the study. Our research was conducted in accordance with the latest Declaration
      of Helsinki.
    

Intervention name(s): Dietary counseling (fat modifed diet); Dietary Counseling (fat modified + soy enriched diet)
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Subjects in both groups had been instructed to achieve specific daily maximum intakes in total fat (≤ 30% of total energy intake), saturated fatty acids (≤10% of total fat intake) and cholesterol (≤ 300 mg). Furthermore the participating families had been trained to replace as many visible fat sources as possible with rapeseed oil due to its favorable composition of polyunsaturated fatty acids.; Subjects in both groups had been instructed to achieve specific daily maximum intakes in total fat (≤ 30% of total energy intake), saturated fatty acids (≤10% of total fat intake) and cholesterol (≤ 300 mg). Furthermore the participating families had been trained to replace as many visible fat sources as possible with rapeseed oil due to its favorable composition of polyunsaturated fatty acids.
Subjects allocated to the soy group and their families were additionally instructed to consume at least 0.25 g of soy protein per kg bodyweight per day and were provided with recipes and practical advice on how to achieve this goal. Example provided: a child with a bodyweight of 30kg would have to consume the equivalent of approx. 50g of Tofu per day to meet the treatment target.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: LDL-Cholesterol; Heterozygous Familial Hypercholesterolemia; Paediatrics; Dietary Treatment