Soy vs Milk Protein for Healthy Nutrition

Recruiting at 1 trial location

Overseen By Melanie Plourde, PhD

Age: 18 - 65

Sex: Any

Trial Phase: Academic

Sponsor: University of Guelph

Must not be taking: Omega-3, Lipid-lowering, Digestive

Disqualifiers: Diabetes, Cardiovascular, Neuropsychiatric, others

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

Compensation: Varies

Number of Visits: Unknown

Duration: 31 days

32 Participants Needed

Trial Summary

Will I have to stop taking my current medications?

If you are using omega-3 supplements, lipid-lowering, or digestive medications, you will need to stop taking them to participate in this trial.

What data supports the effectiveness of the treatment Milk Protein Isolate (MPI) and Soy Protein Isolate (SPI) for healthy nutrition?

Research shows that both soy and milk proteins can maintain short-term nitrogen balance, which is important for healthy nutrition. Studies indicate that well-processed soy proteins are nutritionally comparable to milk proteins, making them effective alternatives for meeting protein needs. ^{1 2 3 4 5}

Is soy protein isolate (SPI) and milk protein isolate (MPI) safe for human consumption?

A study on patients with milk or soy protein enterocolitis (inflammation of the intestine) showed that some individuals may have adverse reactions to both milk and soy protein isolates. This suggests that while generally safe, some people may experience immune-related reactions to these proteins. ^{1 6 7 8 9}

How does the treatment using Milk Protein Isolate (MPI) and Soy Protein Isolate (SPI) differ from other treatments for healthy nutrition?

The treatment using Milk Protein Isolate (MPI) and Soy Protein Isolate (SPI) is unique because it compares plant-based and animal-based protein sources for maintaining nitrogen balance, which is crucial for healthy nutrition. This approach is novel as it evaluates the nutritional value of these proteins in maintaining short-term nitrogen balance, showing that well-processed soy proteins can be as effective as milk proteins. ^{2 3 6 10 11}

What is the purpose of this trial?

Dairy products provide macronutrients, vitamins, and minerals that are important for health and development. Despite this, many Canadians now eat fewer dairy products and are instead consuming more non-dairy alternatives, such as soy. Some of this is because of misconceptions about the effects of dairy on health. However, the study investigators hypothesize that, compared to soy, dairy may actually improve a person's health due to its effects on the enzymes in the body that make omega-3 fatty acids, such as EPA and DHA. The goal of this study is to examine omega-3 metabolism in men and women consuming either milk or soy protein. Briefly, this study will determine if the consumption of milk or soy protein differentially impacts blood EPA and DHA levels, the synthesis of EPA and DHA, fatty acid oxidation, and omega-3 fat absorption from the gut. It is anticipated that the findings from this novel and innovative research project will provide high quality evidence to support a previously unappreciated protective effect of dairy for human health and development.

Eligibility Criteria

This trial is for healthy adult men and pre-menopausal women who can eat soy and dairy products. Participants should be able to understand the study procedures and communicate with clinical staff.

Inclusion Criteria

You need to be able to eat soy and dairy products.

I am a healthy adult man or a pre-menopausal woman.

You need to be able to understand and talk to the doctors and nurses involved in the study.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants consume 2 smoothies per day containing either milk protein isolate or soy protein isolate for 31 days

31 days

Multiple visits for measurements on days 0, 15, 17, 19, 22, 24, 26, 29, 30, and 31

Follow-up

Participants are monitored for changes in EPA and DHA synthesis, fatty acid oxidation, and gene expression after the treatment phase

4 weeks

Treatment Details

Interventions

• Milk Protein Isolate (MPI)
• Soy Protein Isolate (SPI)

Trial Overview The study is testing whether milk protein (MPI) or soy protein (SPI) affects how our bodies handle omega-3 fatty acids, which are important for health. It will look at blood levels of EPA and DHA, their synthesis, fat oxidation, and absorption from the gut.

Participant Groups

Group I: Soy Protein Isolate (SPI) Experimental Treatment 1 Intervention

Study participants in the SPI group will consume 2 smoothies per day for 31 days, where each smoothie provides 300 kcal in total, composed of 45% from carbohydrate (maltodextrin), 20% from protein (soy protein isolate) and 35% from fat (a blend of flaxseed, safflower, and coconut oils). Each smoothie will be mixed with water up to volume of 250mL. Individuals in this group will not consume dairy-containing beverages and foods during the 31-day study.

Group II: Milk Protein Isolate (MPI) Experimental Treatment 1 Intervention

Study participants in the MPI group will consume 2 smoothies per day for 31 days, where each smoothie provides 300 kcal in total, composed of 45% from carbohydrate (maltodextrin), 20% from protein (milk protein isolate) and 35% from fat (a blend of flaxseed, safflower, and coconut oils). Each smoothie will be mixed with water up to volume of 250mL. Individuals in this group will not consume soy-containing beverages and foods during the 31-day study.

Who Is Running the Clinical Trial?

University of Guelph

Lead Sponsor

Trials

87

Recruited

15,100+

Université de Sherbrooke

Collaborator

Trials

317

Recruited

79,300+

Findings from Research

In a study of 43 patients with suspected milk- and/or soy-protein enterocolitis, both powdered and liquid soybean formulas elicited similar rates of adverse reactions, with 33% reacting to powdered soy and 30% to liquid soy.

The findings suggest that many patients with milk protein enterocolitis also have soy protein enterocolitis, and that the order of food challenges may influence reaction rates, indicating a potential local immune response to the protein isolates.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Prospective oral food challenge study of two soybean protein isolates in patients with possible milk or soy protein enterocolitis. Burks, AW., Casteel, HB., Fiedorek, SC., et al.[2023]

In a study involving male Sprague-Dawley rats, both isolated proteins (dairy whey and soy) and protein blends enhanced muscle protein synthesis (MPS) after meals, indicating their effectiveness in promoting muscle growth.

Blend 2, which contained a specific ratio of whey, caseinate, and soy, showed a significantly higher peak in muscle protein synthesis compared to whey protein alone at 135 minutes post-meal, suggesting that certain protein blends may be more beneficial for muscle recovery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A soy, whey and caseinate blend extends postprandial skeletal muscle protein synthesis in rats. Butteiger, DN., Cope, M., Liu, P., et al.[2021]

Partial replacement of soy protein isolate (SPI) with okara dietary fiber (ODF) enhances the gelling properties of SPI gels, improving their hardness and texture, especially in varying salt concentrations.

The study found that ODF reduces SPI's self-aggregation and increases disulfide bond formation, which contributes to better gel quality and higher dietary fiber content in the final product.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Gel properties of okara dietary fiber-fortified soy protein isolate gel with/without NaCl. Lv, Y., Wang, J., Xu, L., et al.[2022]

References

1. England pubmed.ncbi.nlm.nih.gov

Prospective oral food challenge study of two soybean protein isolates in patients with possible milk or soy protein enterocolitis. [2023]

2. United States pubmed.ncbi.nlm.nih.gov

Nitrogen balance response in young men given one of two isolated soy proteins or milk proteins. [2023]

3. Venezuela pubmed.ncbi.nlm.nih.gov

[Biological evaluation, in rats and in humans, of a milk product without lactose, and of a soybean protein formula for use in protein-calorie malnutrition]. [2023]

4. Venezuela pubmed.ncbi.nlm.nih.gov

The nutritive value of Brazilian soy products tested in malnourished children. [2023]

5. United States pubmed.ncbi.nlm.nih.gov

An evaluation of the nutritional value of a soy protein concentrate in young adult men using the short-term N-balance method. [2023]

6. England pubmed.ncbi.nlm.nih.gov

A soy, whey and caseinate blend extends postprandial skeletal muscle protein synthesis in rats. [2021]

7. United States pubmed.ncbi.nlm.nih.gov

A moderate-fat diet containing soy protein does not differentially impact energy balance in male and female mice compared to dairy protein. [2023]

8. United States pubmed.ncbi.nlm.nih.gov

Aqueous ethanol extraction of dietary soy protein isolate improves 59Fe absorption by the rat from a casein-based test meal. [2018]

9. United States pubmed.ncbi.nlm.nih.gov

Intake of soy protein isolate alters hepatic gene expression in rats. [2006]

10. Switzerland pubmed.ncbi.nlm.nih.gov

Antibacterial Soy Protein Isolate Prepared by Quaternization. [2022]

11. England pubmed.ncbi.nlm.nih.gov

Gel properties of okara dietary fiber-fortified soy protein isolate gel with/without NaCl. [2022]