Comparison of the Absorption of Hydrolyzed or Intact Proteins in Morbid Obese (RyDIGEST)

  • End date
    Feb 21, 2024
  • participants needed
  • sponsor
    Assistance Publique - Hôpitaux de Paris
Updated on 21 October 2022


The gastric bypass can reduce the bioavailability of food proteins. The bioavailability of hydrolyzed proteins may be higher than intact proteins. Thus, the use of hydrolyzed proteins could compensate for the decrease in protein bioavailability observed after gastric By-pass in morbidly obese patients.

The effectiveness of a hydrolyzed protein intake may be higher than that of an intact protein intake to improve the status of a By-pass.

The hypothesis would be that the use of hydrolyzed proteins would compensate for the decrease in bioavailability of food proteins caused by gastric By-pass.


Surgery is beneficial in terms of weight loss, correction of comorbidities and life expectancy but adverse effects can occur among which various nutritional deficiencies. Thus, in some cases, more or less marked protein undernutrition may be observed.

To overcome this protein undernutrition, protein supplements can be proposed. However, their effectiveness has not been satisfactorily assessed in this situation to date. Indeed, the protein malabsorption potentially induced by the By-pass limits its impact. The value of protein supplementation must also be considered in terms of overall efficacy, taking into account a possible decrease in spontaneous intake related to supplementation.

For the bioavailability studies, milk proteins will be presented in two different forms of the same origin: intact or hydrolyzed proteins. The proteins of the test meal are marked with 15N nitrogen.

For the three months daily supplementation period, the supplements will be intact proteins not marked with 15N nitrogen, provided to patients in the form of individual sachets. The purpose of this supplementation is to help the patient achieve the protein recommendations, which is 60 g/d.

Condition Morbid Obesity
Treatment Hydrolyzed Proteins, Intact proteins
Clinical Study IdentifierNCT04934826
SponsorAssistance Publique - Hôpitaux de Paris
Last Modified on21 October 2022


Yes No Not Sure

Inclusion Criteria

Patients with BMI > 40 kg/m2 or BMI > 35 kg/m2 associated with at least one comorbidity(s): hypertension, diabetes, cardiovascular disease, hyperlipidemia, sleep apnea, arthritis,hepatic steatosis
Candidates for RY gastric By-pass bariatric surgery
Over 18 and under 60 years of age
For women of childbearing age: effective contraception implemented for at least 3 months
Failure of other medical cares (medical, nutritional, dietetic and psychotherapeutic treatment) well conducted for 6 to 12 months
Patient affiliated to a social security system (excluding AME) or entitled to benefits
Patient who agreed to participate by signing the informed consent of the study

Exclusion Criteria

Pregnancy or breastfeeding in progress
Severe psychiatric disorder or other illness that may disrupt the study follow-up or to invalidate the proper understanding of the protocol information and the informed consent
Patient's foreseeable inability to participate in a clinical trial
Severe and unstable eating disorders
Patients with a contraindication to amino acid infusion
Dependence on alcohol or psychoactive substances such as drugs
Metabolic disease requiring a a low protein diet
Known allergy to milk proteins
Patient under guardianship or curatorship
Patient under the justice protection
Participation in another interventional research
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