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Not yet recruitingNAINTERVENTIONAL

Protein Complementation of Plant-based Diets.

This study wants to find out the best way to get enough protein from plant-based foods. Proteins are vital for your body's growth and daily functions. While animal foods naturally have all the necessary protein building blocks (amino acids), plant foods might be missing some. Some experts say you need to combine certain plant foods in each meal (like beans and rice) to get all the amino acids. Others believe that as long as you eat a variety of plant foods throughout the day, you'll still get everything your body needs. This study will feed participants different plant-based diets over several periods to see which method helps the body use protein more effectively, both in younger and older adults.

At a glance

Status
Not yet recruiting
Phase
NA
Sponsor
The Hospital for Sick Children
Enrolment target
40
Start
01 Oct 2025
Estimated completion
30 Sep 2029

What is this study about?

Proteins are incredibly important for your body; they're like the building blocks that help you grow and keep everything working properly. These building blocks are called amino acids. Animal foods, like meat and fish, naturally contain all the different amino acids your body needs in just the right amounts. This is why they are often called 'high-quality' proteins.

Plant-based foods, like lentils or rice, might have plenty of protein, but they often don't have all the necessary amino acids, or they might have less of one type. For a while, it’s been suggested that if you eat different plant foods together in the same meal – for example, rice and beans, or peanut butter on bread – you can make sure your body gets all the amino acids it needs. This is called ‘protein complementation’.

However, some people believe that you don't necessarily need to combine these foods in every single meal. They think that as long as you eat a good variety of plant foods over the course of a day, your body will gather all the amino acids it needs. This idea has never actually been proven with a scientific study. So, this research aims to compare these two ways of eating plant-based foods to see which one genuinely helps your body use protein best, looking at both younger and older adults.

Key takeaways

  • This study investigates the best way to get complete protein from plant-based diets.
  • It compares eating combined plant proteins in each meal versus eating varied plant proteins throughout the day.
  • The study includes both younger (18-39) and older (60-79) healthy adults.
  • Participants will follow five different 9-day meal plans, with all food provided.
  • The findings will help guide recommendations for plant-based eating.
  • Your contribution could significantly advance our understanding of nutrition.

Who may be eligible?

This study is looking for healthy adults. We're interested in two age groups: young adults between 18 and 39 years old, and older adults between 60 and 79 years old. You need to be generally healthy, meaning you don't have conditions like diabetes that could affect how your body handles protein, and your weight should have been stable recently.

There are also some things that would mean you couldn't take part. This includes if you've lost or gained a lot of weight recently, can't eat the study meals (perhaps due to allergies), drink a lot of coffee or alcohol, or have kidney or liver problems. If you're on certain medications, particularly those affecting protein use, or if blood tests for sugar or kidney function are outside healthy ranges, you wouldn't be able to join.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

  1. Are you between 18-39 or 60-79 years old?
  2. Are you generally healthy, without conditions like diabetes?
  3. Has your weight been stable in the last 3 months?
  4. Are you able to eat plant-based meals provided by the study?
  5. Do you consume less than 2 cups of coffee or 1 alcoholic drink per day?
  6. Are you not currently on medications that affect protein use, like steroids?
Answer every question to see your result.

What does participation involve?

If you take part in this study, you will follow five different dietary plans, each lasting 9 days. During these periods, all your food will be provided by the study, and it will be whole, plant-based foods. You won't be taking any specific medications for the study. To understand how your body uses protein, assessments will involve measuring certain substances in your urine, including a special type of nitrogen that helps us track protein changes. This will help us see how your body builds and breaks down protein. The total length of your involvement will be the five 9-day periods.

Potential risks and benefits

A potential benefit of joining this study is contributing to important knowledge about healthy plant-based eating, which could help many people. While we don't expect major risks, you might find some of the study diets are not to your usual taste, or you could experience minor stomach upset. There is always a small risk associated with blood and urine tests, but these are routine procedures. You are free to withdraw from the study at any time without giving a reason, and this will not affect your medical care.

Locations (1)

  • The Hospital for Sick Children
    Verified postcode
    Toronto, Canada

Common questions

What exactly is 'protein complementation'?

It's when you eat different plant foods together in the same meal, like beans and rice, so you get all the essential protein building blocks your body needs.

Do I have to be a vegetarian or vegan to join?

The study provides plant-based foods, so you'll be eating that diet during the study periods. You don't have to be vegetarian or vegan ordinarily, but need to be willing to eat that way for the study.

How long will I be involved in the study?

You'll participate in five separate 9-day periods, where you'll be following different food plans.

Will I have to prepare my own food?

No, all the meals for the study periods will be provided for you by the research team.

What kind of tests will be done?

We'll mostly be collecting urine samples to see how your body uses protein. There will also be some standard blood tests to check your general health.

How to find out more

Mahroukh Rafii, BSc

Always speak to your GP or specialist before deciding to take part in a study.

Interested in taking part?

Register your interest

Share your details and the research team for "Protein Complementation of Plant-based Diets.…" will contact you if you may be eligible. Always speak to your GP before agreeing to take part.

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