Soy and Brain Vascular Function

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

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.

Study Overview

• Status: Completed
• Conditions: Cerebral Blood Flow; Cognitive Performance; Glucose Metabolism; Brain Vascular Function
• Intervention / Treatment: Dietary supplement: Soy nuts

• Study Type: Interventional
• Enrollment (Actual): 23
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Netherlands
  • Limburg
    • Maastricht, Limburg, Netherlands, 6229 ER
      • Maastricht University Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 60 years to 70 years (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

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)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: PREVENTION
• Allocation: RANDOMIZED
• Interventional Model: CROSSOVER
• Masking: DOUBLE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Experimental: Soy nuts	Dietary supplement: Soy nuts; 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.
NO_INTERVENTION: Control - no soy nuts

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Brain vascular function	Cerebral blood flow as quantified non-invasively by the MRI perfusion method Arterial Spin Labeling (ASL)	Difference between outcomes at the end of a 16-week soy nut intervention and control period.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Glucose metabolism	Oral Glucose Tolerance Test (OGTT)	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Cognitive performance	Cambridge Neuropsychological Test Automated Battery (CANTAB)	Difference between outcomes at the end of a 16-week soy nut intervention and control period.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Other physiological parameters: Peripheral vascular function (1)	Flow-mediated vasodilation (FMD)	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other physiological parameters: Peripheral vascular function (2)	Carotid artery reactivity (CAR)	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other physiological parameters: Peripheral vascular function (3)	Pulse wave analysis (PWA)	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other physiological parameters: Peripheral vascular function (4)	pulse wave velocity (PWV)	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other physiological parameters: Peripheral vascular function (5)	Retinal images	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other physiological parameters: Blood pressure	Office and 24-hour ambulatory blood pressure	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other physiological parameters: Continuous blood glucose	36-hour glycaemic response	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other physiological parameters: Advanced glycation endproducts	Serum protein-bound advanced glycation endproducts (AGEs)	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other physiological parameters: Conventional metabolic risk markers (1)	Lipids and Lipoproteins	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other physiological parameters: Conventional metabolic risk markers (2)	Glucose	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other physiological parameters: Conventional metabolic risk markers (3)	Insulin	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other physiological parameters: Conventional metabolic risk markers (4)	Markers for low-grade systemic inflammation	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other physiological parameters: Conventional metabolic risk markers (5)	Markers for microvascular function	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other physiological parameters: Other parameters (1)	Brain-derived neurotrophic factor (blood)	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other physiological parameters: Other parameters (2)	Cortisol levels (saliva)	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other physiological parameters: Parameters for compliance	Isoflavone levels (urine and blood)	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other perceivable benefits: Quality of Life	The Quality of life (QoL) will be assessed using a 32-item questionnaire	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other perceivable benefits: Sleep characteristics	Sleep characteristics will be assessed using the 10-item Pittsburgh Sleep Quality Index	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other perceivable benefits: Mood	Mood will be tested using the Affect Grid	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other perceivable benefits: Physical fitness (1)	Timed up-and-go test (TUGT)	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other perceivable benefits: Physical fitness (2)	The 6-minute walk test (6 MWT)	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other perceivable benefits: Physical fitness (3)	Handgrip test	Difference between outcomes at the end of a 16-week soy nut intervention and control period.
Other perceivable benefits: Physical fitness (4)	Muscle strength test	Difference between outcomes at the end of a 16-week soy nut intervention and control period.

Collaborators and Investigators

• Sponsor: Maastricht University Medical Center
• Collaborators: Alpro Foundation

Publications and helpful links

General Publications

• Tischmann L, Adam TC, Mensink RP, Joris PJ. Longer-term soy nut consumption improves vascular function and cardiometabolic risk markers in older adults: Results of a randomized, controlled cross-over trial. Clin Nutr. 2022 May;41(5):1052-1058. doi: 10.1016/j.clnu.2022.03.014. Epub 2022 Mar 14.
• Kleinloog JPD, Tischmann L, Mensink RP, Adam TC, Joris PJ. Longer-term soy nut consumption improves cerebral blood flow and psychomotor speed: results of a randomized, controlled crossover trial in older men and women. Am J Clin Nutr. 2021 Dec 1;114(6):2097-2106. doi: 10.1093/ajcn/nqab289.

Study record dates

Study Major Dates

• Study Start (ACTUAL): August 15, 2018
• Primary Completion (ACTUAL): December 31, 2019
• Study Completion (ACTUAL): December 31, 2019

Study Registration Dates

• First Submitted: July 24, 2018
• First Submitted That Met QC Criteria: August 10, 2018
• First Posted (ACTUAL): August 13, 2018

Study Record Updates

• Last Update Posted (ACTUAL): January 18, 2020
• Last Update Submitted That Met QC Criteria: January 15, 2020
• Last Verified: January 1, 2020

More Information

Terms related to this study

• Other Study ID Numbers: METC183017

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No