Nutritional Evaluation of Canola Protein in Comparison With Soy Protein

• Body composition (body status) [ Time Frame: At day 1 ] [ Designated as safety issue: Yes ]
  Bioelectrical impedance analysis, body weight
• Nitrogen balance [ Time Frame: After day 0 and 1 ] [ Designated as safety issue: Yes ]
  Nitrogen balance = nitrogen intake - nitrogen output (urine nitrogen + fecal nitrogen + skin nitrogen); Nitrogen intake was calculated from food uptake; Urine nitrogen contains urea, uric acid, creatinine and total protein; Fecal nitrogen was calculated as the tenth part of the nitrogen intake; Skin nitrogen was calculated as 5.00 mg per kg of body weight

The objective of the study is to evaluate the nutritional and physiological properties of two canola proteins focusing on the bioavailability in humans.

The physiological effects of a single administration of two different industrially manufactured canola proteins (hydrolyzate, isolate) were investigated compared to soy protein.

Twenty-eight healthy men (ø 25 years) completed a double-blind, placebo-controlled, crossover study. The subjects were randomly divided into two groups (group A: canola protein isolate and soy protein isolate and group B: canola protein hydrolyzate and soy protein isolate). After a three-day run-in period, on the intervention day, the subjects consumed a protein drink containing 30.0 g protein powder added to a final volume of 500 mL tomato juice. Half of the subjects in each group consumed a protein drink containing 30.0 g canola protein, the other half received the soy protein. After taking of fasting blood samples in the morning of the intervention day, blood samples were drawn at regular intervals for a period of eight hours. At the end of the run-in period and on the intervention day, a 24-hour urine collection took place.

Within a second experiment (after 4 weeks), the protein source was crossed within the four subgroups for the second intervention.

• Dietary Supplement: Protein drink - protein isolate
  The subjects consumed 500 mL of a protein drink (tomato juice) containing 30 g protein (canola protein isolate or reference protein) after overnight fasting. After run-in period, each volunteer have to pass both protein-intervention days in different order with a four-week wash out period in between.
  Other Name: CPI
• Dietary Supplement: Protein drink - protein hydrolyzate
  The subjects consumed 500 mL of a protein drink (tomato juice) containing 30 g protein (canola protein hydrolyzate or reference protein) after overnight fasting. After run-in period, each volunteer have to pass both protein-intervention days in different order with a four-week wash out period in between.
  Other Name: CPH

• Experimental: Canola protein
  Canola protein (Brassica juncea; incorporated in a drink)
  Interventions:

  • Dietary Supplement: Protein drink - protein isolate
  • Dietary Supplement: Protein drink - protein hydrolyzate
• Active Comparator: Reference protein
  Reference Protein (soy protein isolate; incorporated in a drink)
  Interventions:

  • Dietary Supplement: Protein drink - protein isolate
  • Dietary Supplement: Protein drink - protein hydrolyzate
• No Intervention: Wash out
  Wash out (four weeks without any intervention between interventional periods)
• No Intervention: Run-in
  Run-in period (three days before intervention, defined diet)

Inclusion Criteria:

• Nonsmoker
• Body mass index: 20-26 kg/m²

Exclusion Criteria:

• Intake of pharmaceuticals
• Allergy against canola protein or soy protein
• Kidney disease