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Completed

NCT Number: NCT03627637

Soy and Brain Vascular Function

Cognitive performance is negatively related to an impaired glucose metabolism, possibly due to impairments in brain vascular function. Supported by the statement from the American Heart and American Stroke Association that healthy plant-based diets, which consist of soy foods, protect against cognitive decline, we now hypothesize that soy-induced changes in glucose metabolism cause beneficial effects on brain vascular function thereby improving cognitive performance. The primary objective of this intervention study is thus to evaluate in elderly men and women the effect of a 16-week soy intervention on cerebral blood flow, as quantified by the non-invasive gold standard magnetic resonance imaging (MRI) perfusion method Arterial Spin Labeling (ASL). Cerebral blood flow is a robust and sensitive physiological marker of brain vascular function. Secondary objectives are to examine effects on glucose metabolism using the oral glucose tolerance test and cognitive performance as assessed with a neurophysiological test battery.

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Key information

Conditions

Brain Vascular Function Cerebral Blood Flow Cognitive Performance Glucose Metabolism

Age range

60 year–70 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Maastricht University Medical Center

Maastricht, Limburg, 6229 ER, Netherlands

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Aged between 60-70 years
  • BMI between 20-30 kg/m2
  • 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

  • Allergy or intolerance to soy
  • Current smoker, or smoking cessation < 12 months
  • Diabetic patients
  • Familial hypercholesterolemia
  • Abuse of drugs
  • More than 3 alcoholic consumptions per day
  • Use of soy 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

Soy nuts

Dietary Supplement

Study volunteers will receive daily 70 g of soy nuts (roasted soybeans containing approximately 100 mg isoflavones). The amount of soy protein provided by the nuts equals the FDA recommended daily intake of 25-30 g.

Primary outcomes

  1. Brain vascular function

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Cerebral blood flow as quantified non-invasively by the MRI perfusion method Arterial Spin Labeling (ASL)

Secondary outcomes

  1. Glucose metabolism

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Oral Glucose Tolerance Test (OGTT)

  2. Cognitive performance

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Cambridge Neuropsychological Test Automated Battery (CANTAB)

Other outcomes

  1. Other physiological parameters: Peripheral vascular function (1)

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Flow-mediated vasodilation (FMD)

  2. Other physiological parameters: Peripheral vascular function (2)

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Carotid artery reactivity (CAR)

  3. Other physiological parameters: Peripheral vascular function (3)

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Pulse wave analysis (PWA)

  4. Other physiological parameters: Peripheral vascular function (4)

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    pulse wave velocity (PWV)

  5. Other physiological parameters: Peripheral vascular function (5)

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Retinal images

  6. Other physiological parameters: Blood pressure

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Office and 24-hour ambulatory blood pressure

  7. Other physiological parameters: Continuous blood glucose

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    36-hour glycaemic response

  8. Other physiological parameters: Advanced glycation endproducts

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Serum protein-bound advanced glycation endproducts (AGEs)

  9. Other physiological parameters: Conventional metabolic risk markers (1)

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Lipids and Lipoproteins

  10. Other physiological parameters: Conventional metabolic risk markers (2)

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Glucose

  11. Other physiological parameters: Conventional metabolic risk markers (3)

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Insulin

  12. Other physiological parameters: Conventional metabolic risk markers (4)

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Markers for low-grade systemic inflammation

  13. Other physiological parameters: Conventional metabolic risk markers (5)

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Markers for microvascular function

  14. Other physiological parameters: Other parameters (1)

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Brain-derived neurotrophic factor (blood)

  15. Other physiological parameters: Other parameters (2)

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Cortisol levels (saliva)

  16. Other physiological parameters: Parameters for compliance

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Isoflavone levels (urine and blood)

  17. Other perceivable benefits: Quality of Life

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    The Quality of life (QoL) will be assessed using a 32-item questionnaire

  18. Other perceivable benefits: Sleep characteristics

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Sleep characteristics will be assessed using the 10-item Pittsburgh Sleep Quality Index

  19. Other perceivable benefits: Mood

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Mood will be tested using the Affect Grid

  20. Other perceivable benefits: Physical fitness (1)

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Timed up-and-go test (TUGT)

  21. Other perceivable benefits: Physical fitness (2)

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    The 6-minute walk test (6 MWT)

  22. Other perceivable benefits: Physical fitness (3)

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Handgrip test

  23. Other perceivable benefits: Physical fitness (4)

    Time frame: Difference between outcomes at the end of a 16-week soy nut intervention and control period.

    Muscle strength test

Sponsors and collaborators

Lead sponsor

Maastricht University Medical Center

Other

Collaborators

  • Alpro Foundation

Registry information

Official study title

The Effects of Soy on Brain Vascular Function in Elderly Men and Women

Important dates

Study start
2018
Primary completion
2019
Study completion
2019
First posted
Aug 13, 2018
Registry last updated
Jan 18, 2020

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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