Peanut Butter and Brain Health

Long-term Peanut Butter Consumption and Brain Health in Humans

Healthy foods, including peanuts, may improve brain function, which is essential for cognitive and metabolic health, and may contribute to improved food intake regulation. It is therefore important to investigate the specific effects of peanut butter on cerebral blood flow responses, as well as the potential associated functional benefits. The researchers hypothesize that long-term peanut butter consumption improves vascular function in the brain, thereby enhancing cognitive performance and appetite control in middle aged and older adults. Objective: The primary objectives are to investigate in middle aged and older men and women the effect of 16-week peanut butter consumption on brain vascular function, while we will also assess changes in cognitive performance and appetite-related brain reward activity (secondary objectives). Cerebral blood flow responses (brain vascular function) will be non-invasively quantified by the non-invasive gold standard magnetic resonance imaging (MRI)-perfusion method Arterial Spin Labeling (ASL).Study design: This intervention study will have a randomized, controlled, cross-over design. The total study duration will be 40 weeks, including two 16-week interventions, separated by a washout period of at least 8 weeks. Study population: Forty-five middle-aged and older men and women (aged 45-75 years) without a history of cardiovascular diseases or complaints will participate. This population is expected to have a decreased cerebral blood flow at baseline and are also at increased risk of cognitive impairment, allowing for improvement by the intervention. Intervention: Study participants will receive, in random order, 45 g of peanut butter daily (peanut intervention) or no peanut butter (control) for a total of 16 weeks, separated by a wash-out period of at least 8 weeks. Main study parameters/endpoints: At baseline, first anthropometric measurements will be performed and blood pressure will be determined. In addition, a fasting blood sample will be drawn. Another fasting blood sample will be drawn at eight weeks, while participants have to attend the research facilities to perform follow-up measurements after sixteen weeks. The primary endpoint is the difference at follow-up in the cerebral blood flow response between peanut butter intervention and control periods. Cognitive performance will be assessed, while the researchers will also focus on appetite-related brain reward activity (secondary outcomes).

Inclusion Criteria:

• Men and women, aged between 45-75 years
• Women postmenopausal: two or more years after last menstruation
• 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 peanuts
• Left-handedness (effects on brain health differ between left- and right-handed adults)
• 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 of 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)