RecruitingNAINTERVENTIONAL

The Effect of Pistachio-Rich Breakfast Meals on Cognitive Function in Healthy Older Adults

This study is exploring whether eating pistachios for breakfast can help improve thinking and memory skills in healthy older adults, specifically those aged 65 to 80. Participants will try different amounts of pistachios at breakfast, or a meal without them, over several weeks. Researchers will then check their memory, attention, and other brain functions throughout the day. They will also collect blood samples to understand general health markers and use special tests to look at brain activity and blood flow. The main goal is to see if pistachios could have a positive effect on brain health as people get older. This research could help us learn more about healthy eating for our brains.

At a glance

Status

Recruiting

Phase

Sponsor

University of Reading

Enrolment target

Start

06 Mar 2025

Estimated completion

01 Feb 2026

Cognition

What is this study about?

You might be interested in this study if you're a healthy adult aged 65 to 80 and want to understand how certain foods can affect your brain. This research is trying to find out if eating pistachios for breakfast can help with things like memory, attention, and how quickly you think throughout the day. Scientists want to see if pistachios can give your brain a helpful boost.

To do this, volunteers will be given breakfast meals with either a small, medium, or large amount of pistachios, or a breakfast without them (a 'placebo'). Over several weeks, participants will try each of these different breakfasts. After each special breakfast, researchers will carry out various activities and tests to measure how well your brain is working over the next six hours. They will also take blood samples to look for clues about your overall health and brain well-being.

Additionally, some participants might have extra tests, like an EEG, which measures brain waves, or an FMD test, which checks blood flow. All these measurements help the researchers understand not just *if* pistachios have an effect, but *how* they might be influencing brain health. The information gathered from this study could be really important in helping us learn more about how diet can support a healthy brain as we get older.

Key takeaways

This study investigates if pistachios for breakfast can boost thinking skills in older adults.
Participants will eat different amounts of pistachios or a control meal over several weeks.
Memory, attention, and other brain functions will be tested throughout the day.
Blood samples and some brain/blood vessel tests will help understand the effects.
It helps us learn more about how diet supports brain health as we age.

Who may be eligible?

This study is looking for healthy men and women between the ages of 65 and 80. To take part, you should generally eat no more than four portions of fruits and vegetables each day, and no more than three portions of fish per week. You also need to be able to understand English well enough to follow instructions and have good enough eyesight and hearing for the study tasks. Your body weight should be within a healthy range for your age, and a quick memory test should show your brain function is typical for your age.

There are some reasons why you might not be able to join. For example, if you have been diagnosed with mental health conditions, ADHD, or dyslexia. Also, if you have any food allergies or intolerances, or if you take medications or supplements that might affect the study results, you won't be able to participate. Recent antibiotic use (within the last 3 months) or following specific diets like vegan or vegetarian diets would also mean you can't join, as these might affect the study outcomes.

Finally, if you have certain existing health conditions like type 2 diabetes, heart problems, untreated high blood pressure, or blood clotting disorders, you won't be eligible. If you are taking blood thinners, you also cannot participate. The aim is to study healthy older adults, so these exclusions help ensure the results are clear.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you between 65 and 80 years old?
Do you generally eat a healthy amount of fruits, vegetables (max 4 servings/day), and fish (max 3 servings/week)?
Are you able to speak and understand English well, and have good eyesight and hearing for tasks?
Do you have any food allergies or medical conditions like diabetes, heart disease, or untreated high blood pressure?
Have you taken antibiotics in the last 3 months, or are you on blood thinners?
Are you a healthy individual without specific diagnosed mental health conditions or learning difficulties (like ADHD/dyslexia)?

Answer every question to see your result.

What does participation involve?

If you decide to take part, you'll first have a screening visit to make sure you're suitable for the study. After that, there will be four main testing visits, with roughly one week between each visit.

Before each of these four testing days, you'll need to follow specific instructions: from 8:30 pm the evening before, you must only drink water – no tea, coffee, or alcohol, and no food. On the morning of the test, before you come in, you should only eat one piece of buttered white toast and a glass of water.

During each of the four testing visits, you'll eat a special breakfast (either with pistachios or without). You'll then do various memory and mood tests at the start, and again 2, 4, and 6 hours later. Blood samples will be taken towards the end of the day. Some participants might also have extra tests: blood flow measurements (FMD) taken at the start, then 2, 4, and 6 hours later, and brain wave measurements (EEG) taken at the 6-hour mark. The total duration for your participation would be about one month for the testing visits, plus the initial screening.

Potential risks and benefits

There are no major risks expected in this study, as it involves eating common food items. The main benefit for participants is that you will contribute to scientific understanding about how diet can affect brain health as we age. While we don't know for certain if you personally will experience any direct health benefits from the pistachios, the information gained could help others in the future. You are free to withdraw from the study at any time, for any reason, without it affecting your medical care.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

Nutrition, Cognition & Health Lab, School of Psychology and Clinical Language Sciences, University of Reading
Verified postcode
Reading, United Kingdom· Recruiting

Common questions

What will I have for breakfast during the study?

You will have a special breakfast with different amounts of pistachios, or a breakfast without them, depending on the test day.

How many times do I need to visit?

You'll have one initial screening visit and then four main testing visits, each about a week apart, for a total of five visits.

What kind of tests will I do?

You'll do memory and mood tests, have blood samples taken, and some participants might have extra tests for brain activity (EEG) or blood flow (FMD).

Can I eat normally before the visits?

No, you'll need to fast (no food or drinks except water) from 8:30 pm the night before, and only have one piece of buttered toast and water on the morning of each test visit.

Will this study help my memory directly?

While the study aims to understand the effects of pistachios on memory, we can't guarantee you'll personally feel a direct benefit. Your participation helps advance scientific knowledge.

How to find out more

Claire Williams, PhD

claire.williams@reading.ac.uk 0118 378 7540 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.