Protein Complementation for Plant-Based Diets

Overseen By Mahroukh Rafii, BSc

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: The Hospital for Sick Children

Must not be taking: Steroids

Disqualifiers: Diabetes, Renal failure, Liver disease, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores how different methods of consuming plant proteins affect the body's protein utilization. Researchers aim to determine whether consuming grains and legumes together, such as rice and beans, benefits the body more than eating them separately throughout the day. This method, known as protein complementation, targets healthy young adults (18-39 years) and older adults (60-79 years) with stable weight and no conditions affecting protein use. The study seeks to identify the best way to obtain complete proteins from plant foods. As an unphased trial, participants contribute to groundbreaking research on optimizing plant-based diets for better health.

Will I have to stop taking my current medications?

You may need to stop taking any medications that affect protein or amino acid metabolism, like steroids, to participate in this trial.

What prior data suggests that protein complementation is safe for human consumption?

Research has shown that plant-based diets, including foods like beans and rice, are generally safe for everyone. Studies have found that while plant proteins might lack some amino acids, combining different plants can provide all the amino acids the body needs.

For instance, eating rice with beans or peanut butter with bread can offer a balanced protein intake. Evidence suggests that these combinations meet the body's protein requirements. It's important to know that plant-based diets are safe and can support growth and bodily functions.

Overall, eating a variety of plant foods can help maintain a healthy and balanced diet. For those considering joining a study on plant protein combinations, research indicates it's a safe and well-tolerated approach. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about protein complementation for plant-based diets because it offers a novel way to optimize protein intake without relying solely on animal products. Unlike traditional methods that depend on a single source of plant protein, this approach combines different plant proteins to create a complete amino acid profile, potentially enhancing protein synthesis and balance. This could be particularly beneficial for those following plant-based diets by improving muscle health and overall nutrition more efficiently than existing options.

What evidence suggests that protein complementation is effective for improving protein metabolism?

Research shows that combining different plant foods can enhance the quality of a plant-based diet. For instance, eating grains and legumes, such as rice and beans, together in a meal provides all the essential protein building blocks the body needs. This combination can make plant-based protein comparable to protein from animal sources. Studies have found that vegetarian diets, which often use this method, are linked to a 28% lower risk of heart disease. While it's not necessary to combine these foods in every meal, ensuring daily intake of all essential protein building blocks supports healthy growth and body functions. Participants in this trial will have their protein synthesis, breakdown, and balance assessed after exposure to five different diets consumed over nine days to evaluate the effectiveness of protein complementation. ^{2 4 6 7 8}

Who Is on the Research Team?

Glenda Courtney-Martin, PhD, RD

Principal Investigator

Research Institute, The Hospital for Sick Children

Are You a Good Fit for This Trial?

This trial is for adults who are interested in understanding how plant-based diets can be optimized for protein intake. Participants will need to follow specific whole food diets provided over several days and should not have dietary restrictions that could interfere with the study.

Inclusion Criteria

I am 18-39, healthy, with stable weight, not on specific meds, and have normal blood tests.

I am a healthy adult aged 60-79, with stable weight, not on specific meds, and normal blood tests.

Exclusion Criteria

Recent history of weight loss within the last 3 months or on a weight reducing diet, Inability to tolerate study diets (e.g., Allergy to ingredients)

Significant alcohol consumption (>1 drink per day i.e. 1 beer or ½ glass of wine)

Significant caffeine consumption (>2 cups per day)

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Dietary Intervention

Participants consume 5 different diets over a period of 9 days to assess protein synthesis, breakdown, and balance.

9 days

Follow-up

Participants are monitored for safety and effectiveness after the dietary intervention

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Protein Complementation

Trial Overview The study tests whether combining different plant foods (like rice and beans) provides a complete protein compared to eating them separately within a day. It's a cross-over study, meaning participants will try both diet types at different times.

How Is the Trial Designed?

Group I: protein synthesis, breakdown and balance assessed after exposure to 5 diets consumed over 9d Experimental Treatment 2 Interventions

Who Is Running the Clinical Trial?

The Hospital for Sick Children

Lead Sponsor

Trials

724

Recruited

6,969,000+

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC8623061/

The Safe and Effective Use of Plant-Based Diets with ... Pooled data from seven prospective cohort studies showed a reduced CHD incidence and mortality of 28% and 22%, respectively, associated with vegetarian diets.

2. clinicaltrials.gov clinicaltrials.gov/study/NCT07151625

Protein Complementation of Plant-based Diets. Complementation of plant proteins with complementary amino acid profile (cereal grain + legume) in each meal can improve the protein quality of ...

3. nature.com nature.com/articles/s41598-025-17087-x

Perspectives of adults aged 55+ on plant-based diets rich ... In contrast, plant-based protein intake showed little change (+ 1.9 ± 1.1 g), resulting in a higher proportion of animal-based proteins in the ...

4. jn.nutrition.org jn.nutrition.org/article/S0022-3166(24)00450-4/fulltext

A Systematic Review - The Journal of Nutrition The reported protein intakes across the 4 plant-based diets met the dietary recommendation of 10%–35% total energy from protein intake [11].

5. academic.oup.com academic.oup.com/nutritionreviews/article/83/7/e2063/7921515

Achieving High Protein Quality Is a Challenge in Vegan Diets This narrative review describes the challenges of achieving high protein quality from vegan diets. Data were synthesized from peer-reviewed research articles ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC6893534/

Dietary Protein and Amino Acids in Vegetarian Diets—A Review While animal products are rich in protein, the adequacy of dietary protein intake from vegetarian/vegan diets has long been controversial.

7. sciencedirect.com sciencedirect.com/science/article/pii/S0022316624004504

Protein Adequacy, Plant Protein Proportion, and Main Plant ... Our findings show that total protein intake was similar across the plant-based diets and that all diets met the dietary recommendations for protein intake. As ...

8. massgeneral.org massgeneral.org/news/article/spotlight-on-plant-based-proteins

Spotlight on Plant Based Proteins The following list highlights protein-rich plant foods, their completeness, and ways to incorporate them into your diet.