Effect of Daily Walnut Consumption on Memory in Subjects With Long-COVID

Completed · Not applicable

Conditions studied: Long-COVID, Brain Fog, Cognition, Memory

In brief

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.

Key facts

Study ID

NCT07429903

Run by

University of California, Los Angeles

People needed

31

Starts

2023-09-21

Expected to finish

2025-01-24

Last updated by the study team

2026-02-24

Who can join

Age: 40 and older. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

• 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

You may not qualify if…

• 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
• Regular consumption of more than 5 oz of walnuts per week
• 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

Where it is running

• UCLA Center for Human Nutrition — Los Angeles, California, United States

Full record on ClinicalTrials.gov

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