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NCT Number: NCT07057245

Effects of Protein Supplementation on Brain Function

Protein-rich foods may improve brain insulin-sensitivity, which is important for cognitive and metabolic health, and may also translate into an improved food intake regulation. It is therefore pertinent to delineate the effects of plant-derived proteins, which are a more sustainable alternative to animal-derived proteins, on brain insulin-sensitivity and related functional benefits. The hypothesis is that daily plant-derived or animal-derived protein supplementation improves brain vascular function and insulin-sensitivity, thereby improving cognitive performance and appetite control in overweight or obese older men and women.

The primary objective is to investigate in overweight or obese older adults the effect of daily protein supplementation for two weeks with either a plant-derived protein or an animal-derived protein on vascular function and insulin-sensitivity in the brain, while changes in cognitive performance and appetite-related brain reward activity will also be evaluated (secondary study objectives). Cerebral blood flow responses before (brain vascular function) and after the administration of intranasal insulin spray (brain insulin-sensitivity) will be quantified by the gold standard magnetic resonance imaging (MRI)-perfusion method Arterial Spin Labeling (ASL).

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Key information

Conditions

Brain Vascular Function Brain Insulin Sensitivity Cerebral Blood Flow Cognitive Function Satiety

Age range

60 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Maastricht University Medical Center

Maastricht, Limburg, 6229ER, Netherlands

Location status: Recruiting

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Men and women, aged between 60-75 years (older adults)
  • BMI between 25-35 kg/m2 (overweight or obese)
  • Fasting plasma glucose < 7.0 mmol/L
  • Fasting serum total cholesterol < 8.0 mmol/L
  • Fasting serum triacylglycerol < 4.5 mmol/L
  • Systolic blood pressure < 160 mmHg and diastolic blood pressure < 100 mmHg
  • Stable body weight (weight gain or loss < 3 kg in the past three months)
  • Willingness to give up being a blood donor from 8 weeks before the start of the study, during the study and for 4 weeks after completion of the study
  • No difficult venipuncture as evidenced during the screening visit

Exclusion criteria

  • Intolerant to milk products or fava bean allergy
  • Vegetarians
  • Left-handedness
  • Current smoker, or smoking cessation < 12 months
  • Diabetic patients
  • Familial hypercholesterolemia
  • Abuse of drugs
  • More than 3 alcoholic consumptions per day
  • Use of products or dietary supplements known to interfere with the main outcomes as judged by the principal investigators
  • Use medication to treat blood pressure, lipid, or glucose metabolism
  • Use of an investigational product within another biomedical intervention trial within the previous 1-month
  • Severe medical conditions that might interfere with the study, such as epilepsy, asthma, kidney failure or renal insufficiency, chronic obstructive pulmonary disease, inflammatory bowel diseases, auto inflammatory diseases, and rheumatoid arthritis
  • Active cardiovascular disease like congestive heart failure or cardiovascular event, such as an acute myocardial infarction or cerebrovascular accident
  • Contra-indications for MRI imaging (e.g., pacemaker, surgical clips/material in body, metal splinter in eye, claustrophobia)

Treatment and study plan

Protein supplementation with an animal-based protein isolate

Dietary Supplement

Study participants will consume, in random order, twice daily (2 x ~20 g) a plant protein (fava bean protein isolate), animal protein (milk protein isolate) or control (cornstarch providing no extra protein)

Protein supplementation with a plant-based protein isolate

Dietary Supplement

Study participants will consume, in random order, twice daily (2 x ~20 g) a plant protein (fava bean protein isolate), animal protein (milk protein isolate) or control (cornstarch providing no extra protein)

Control arm - cornstarch

Other

Study participants will consume, in random order, twice daily (2 x ~20 g) a plant protein (fava bean protein isolate), animal protein (milk protein isolate) or control (cornstarch providing no extra protein)

Primary outcomes

  1. Cerebral blood flow responses before (brain vascular function) and after the administration of intranasal insulin spray (brain insulin-sensitivity)

    Time frame: Measured after 2 weeks of supplementation with protein isolate or control

Secondary outcomes

  1. Cognitive performance

    Time frame: Measured after 2 weeks of supplementation with protein isolate or control

    Cognitive performance will be assessed with a neuropsychological test battery

  2. Appetite-related brain reward activity

    Time frame: Measured after 2 weeks of supplementation with protein isolate or control

    Blood oxygenation level-dependent (BOLD)-functional MRI (fMRI) response to food cues

Other outcomes

  1. Transcranial Doppler ultrasound

    Time frame: Measured after 2 weeks of supplementation with protein isolate or control

    Blood flow velocity in the MCA

  2. Blood pressure

    Time frame: Measured at baseline and after two weeks of supplementation with protein isolate or control

    Office BP (SBP and DBP) measured in mmHg

  3. Heart rate

    Time frame: Measured at baseline and after two weeks of supplementation with protein isolate or control

    Heart rate (HR) measured in beats/min

  4. Metabolic risk markers - Fasting lipids

    Time frame: Measured at baseline and after two weeks of supplementation with protein isolate or control

    Fasting lipids:

    • Fasting serum triacylglycerol (TAG) concentrations in mmol/L will be measured
    • Fasting serum total cholesterol (TC) and HDL-C in mmol/L will be measured

  5. Metabolic risk markers - glucose and insulin

    Time frame: Measured at baseline and after two weeks of supplementation with protein isolate or control

    Fasting glucose and insulin:

    • Fasting plasma glucose concentrations in mmol/L will be measured
    • Fasting serum insulin concentrations in mmol/L will be measured

  6. Metabolic risk markers - Low-grade systemic inflammation and microvascular function

    Time frame: Measured at baseline and after two weeks of supplementation with protein isolate or control

    Low-grade systemic inflammation and microvascular function:

    • Fasting hemostatic factors and plasma markers related to systemic inflammation will be measured to assess low-grade systemic inflammatory responses (e.g. CRP)
    • Fasting plasma markers related to microvascular function will be measured to determine microvascular responses

  7. Single nucleotide polymorphisms (SNPs)

    Time frame: Measured once during the start of the study

    Leucocytes will be isolated from EDTA blood. DNA will be isolated from these leucocytes according to standard procedures. DNA will be used for analyzing the presence of known SNPs in genes encoding proteins known to play a role in cholesterol metabolism.

  8. Perceived hunger and satiety

    Time frame: Measured after 2 weeks of supplementation with protein isolate or control

    Visual analogue scale (VAS) questionnaires will be used to assess perceived feelings of hunger, fullness, desire to eat, and prospective food consumption.

  9. Anthropometric measurements

    Time frame: Measured at baseline and after two weeks of supplementation with protein isolate or control

    At all test days, anthropometric measurements (weight, length, waist and hip circumferences as indirect measures of fat distribution, and skinfold measurements) will be measured

  10. Dietary intake

    Time frame: Measured after 2 weeks of supplementation with protein isolate or control

    At the end of both interventions, food intake will be measured using a validated food frequency questionnaire (FFQ)

Interested in participating?

Recruiting

Interested in participating?

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Sponsors and collaborators

Lead sponsor

Maastricht University Medical Center

Other

Collaborators

  • Cosun

Registry information

Official study title

Effects of Daily Protein Supplementation on Brain Function in Older Adults With Overweight or Obesity

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Jul 9, 2025
Registry last updated
Jul 9, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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