NCT07429903Completed
Effect of Daily Walnut Consumption on Memory in Subjects With Long-COVID
Source: ClinicalTrials.gov · Last updated 24 Feb 2026
Brief summary (registry, in English)
Approximately 30% of patients experience "Long-COVID" syndrome presenting with symptoms such as cognitive difficulties ('brain fog'), fatigue, dyspnea, autonomic dysfunction, depression and anxiety, lasting beyond 12 weeks causing significant disability, and threaten health and wellbeing of millions around the world. At the current time, there is no effective treatment for long-COVID. Walnuts contain a mixture of nutrients and phytochemicals include monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), and alpha-linolenic acid (ALA). Walnut consumption was directly associated with cognitive function. The investigators have shown pomegranate that share the same phytonutrient ellagitannins as walnut and mixed nuts including walnuts could increase blood microbiome metabolites of tryptophan metabolite indole propionate and serotonin levels via change of gut microbiota and therefore play an essential role in gut-brain axis including cognitive function. The proposed pilot study will include 76 adults (ages \>40 years) with diagnosis of SARS-CoV2 infection presenting with long-COVID symptoms lasting longer than 12 weeks. They will be randomized 1:1 to usual care vs. an intervention group that will include 2 oz (57g) of walnuts daily into their habitual diet for 12 weeks. The investigators will compare the improvement in symptoms of cognitive complains of "brain fog", fatigue and depression of the active intervention group vs. usual care. The outcome of the investigation of the benefit of walnut consumption will provide important novel information on using dietary sources of polyunsaturated fatty acids and phytochemicals to mitigate the common symptoms of long-COVID. This application was submitted in response to the California Walnut Commission's commodity board topic.
- Status (registry)
- Completed
- Study type
- Interventional
- Enrollment
- 31 (actual)
- First submitted
- 23 Jan 2026
- Start date
- 21 Sept 2023
- Primary completion date
- 24 Jan 2025
- Lead sponsor
- University of California, Los Angeles
- Diseases
- Long COVID and ME/CFS
- NCT number
- NCT07429903
What you commit to
- Study type: Interventional
- Participants enrolled: 31
- From 21 Sept 2023 to the primary completion date, 24 Jan 2025
- 1 site in 1 country
- Visits and tests: ask the trial team, the registry does not list them
Built from the registry fields of ClinicalTrials.gov. It describes the study, not your situation.
Who cannot take part
Copied verbatim from ClinicalTrials.gov and grouped by topic. Only the trial team decides who can take part.
Other illness
- Diagnosis of probable Alzheimer's disease or other dementia (e.g., vascular, Lewy body, frontotemporal)
- Other neurological or medical conditions that may cause cognitive impairment
- Evidence of Parkinson's disease based on motor examination
- Uncontrolled hypertension (systolic BP \>170 mmHg or diastolic BP \>100 mmHg)
- Allergy to walnuts
- Current diagnosis of a major psychiatric disorder according to DSM-5 criteria
- Alcoholism or substance use disorder
- Any condition that, in the investigator's judgment, would make participation unsafe or interfere with study completion
Other
- Regular consumption of more than 5 oz of walnuts per week
Who the study is looking for
- Age 40 years and older
- History of confirmed SARS-CoV-2 infection
- Presence of long-COVID symptoms lasting longer than 12 weeks, including one or more of the following:
- Cognitive complaints ("brain fog," memory, attention, or processing speed difficulties)
- Fatigue
- Mood symptoms (e.g., depression)
- Consumption of a low-polyphenol (Western) diet
- Adequate visual acuity and hearing to complete neuropsychological testing
- Screening laboratory results without clinically significant abnormalities that would interfere with study participation
- Ability and willingness to provide written informed consent
Age in the registry: 40 years to - · Sex: All · Does not accept healthy volunteers
Sites (1)
Sites in registry order. Pick your city on the disease page to sort them by distance.
| Site | City | Country | Site status |
|---|---|---|---|
| UCLA Center for Human Nutrition Coordinator of this site? Confirm its status | Los Angeles | United States | Unknown status |
This page is information, not medical advice. Discuss any trial with your doctor.