Tag: nutritional supplements

Effects of Cacao Flavonoids in Long COVID-19 Patients with Chronic Fatigue: FLALOC, a Placebo-Controlled Randomized Clinical Trial

Abstract:

Background: In the context of long COVID, persistent fatigue is among the most prevalent symptoms that can develop after SARS-CoV-2 infection. Mitochondrial myopathy and endothelial dysfunction, which are triggers of inflammation, have emerged as prominent causes of long COVID-induced fatigue. Interestingly, the intake of flavanols, particularly (−)-epicatechin (EC), has been associated with the positive modulation of endothelial and mitochondrial structure and function.
Methods: In this work, we conducted a randomized, double-blind, placebo-controlled clinical trial to determine whether an EC-enriched supplement (ECES) improves plasma markers of inflammation, endothelial structure, and fatigue-related endpoints in patients with long COVID-19.
Results: The study included 46 subjects (mean age 52 years) who were instructed to consume two capsules/day for 90 days of either ECES (n = 23) or placebo (n = 23). Endpoints assessed included mean changes in plasma inflammatory markers (IL-1β, IL-6, and TNF-α) and endothelial dysfunction markers (syndecan-1), handgrip strength, fatigue scale, and quality of life (QoL). The results showed significant improvements in the ECES group for inflammatory markers, syndecan-1, and fatigue compared with the placebo group.
Conclusions: The results yield intriguing positive findings for EC and open a new avenue for treating long COVID.
Source: Munguía L, Silva S, Villarreal F, Nájera N, Ceballos G. Effects of Cacao Flavonoids in Long COVID-19 Patients with Chronic Fatigue: FLALOC, a Placebo-Controlled Randomized Clinical Trial. Journal of Clinical Medicine. 2026; 15(4):1468. https://doi.org/10.3390/jcm15041468 https://www.mdpi.com/2077-0383/15/4/1468 (Full text)

Vitamin D in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome After COVID-19 or Vaccination: A Randomized Controlled Trial

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) can develop as post-vaccination syndrome (PVS) or Post-Acute Sequelae of SARS-CoV-2 infection (PASC). In our prior retrospective study, most patients with PVS who developed ME/CFS had vitamin D insufficiency or deficiency. We evaluated the efficacy of vitamin D replacement therapy guidance for ME/CFS symptom improvement in patients with vitamin D insufficiency or deficiency.

Methods: This open-label randomized controlled trial enrolled 91 participants with ME/CFS as PVS or PASC and serum 25(OH) vitamin D < 30 ng/mL across five clinical sites. Participants were randomized 1:1 to intervention (active vitamin D preparation plus vitamin D replacement therapy guidance: 25 μg daily supplementation, dietary counseling, sun exposure, and exercise) or control (active vitamin D preparation alone) for 12 weeks. The primary endpoint was the change in ME/CFS symptom count from screening to Week 12.

Results: Mean symptom change was -6.7 in the intervention group versus -1.2 in the control group (between-group difference -5.6; 95% CI: -7.2, -3.9; p < 0.001). Serum 25(OH) vitamin D improved from 18.6 to 27.1 ng/mL in the intervention group, while the control group showed a decreasing trend (between-group difference 10.2 ng/mL; 95% CI: 7.9, 12.5). Achievement of <8 symptoms (i.e., no longer meeting ME/CFS diagnostic criteria) was significantly higher in the intervention group, with 16 participants achieving this threshold compared to 1 in the control group (p < 0.001). Subgroup analyses showed consistent benefit in both PVS (n = 56) and PASC (n = 29) cohorts.

Conclusions: Vitamin D replacement therapy guidance significantly reduced ME/CFS symptoms along with improvement of serum 25(OH) vitamin D levels in patients with vitamin D insufficiency or deficiency who developed ME/CFS as PVS or PASC.

Source: Kodama S, Nakata M, Konishi N, Yoshino M, Fujisawa A, Naganuma M, Kobayashi Y, Hirai Y, Kitagawa A, Miyokawa M, Mishima R, Teramukai S, Fukushima M. Vitamin D in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome After COVID-19 or Vaccination: A Randomized Controlled Trial. Nutrients. 2026 Feb 3;18(3):521. doi: 10.3390/nu18030521. PMID: 41683343. https://www.mdpi.com/2072-6643/18/3/521 (Full text)

Use and Perceived Helpfulness of Different Intervention Strategies in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Depression

Abstract:

Background: Patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) or depression both frequently report debilitating exhaustion, yet the two conditions differ in their etiological and diagnostic clarity, and clinical management. This study aimed to examine differences in the use and perceived helpfulness of a broad range of conventional treatments and complementary interventions, including nutritional approaches, between patients with ME/CFS and depression.

Methods: A cross-sectional online survey was conducted in 2024. A total of 819 participants self-identified as having either ME/CFS (n = 576) or depression (n = 243). Participants (80% female) reported their use and perceived helpfulness of 52 treatments and interventions, encompassing behavioral therapies, medications, and dietary supplements. Group differences were examined using multivariate analyses of variance and covariance (MANOVA/MANCOVA). Open-ended responses were analyzed descriptively using thematic grouping and frequency counts.

Results: Participants with depression most commonly reported the use of psychotherapy (M = 2.49, SD = 1.00) and antidepressant medication (M = 2.44, SD = 2.30), and they rated fewer interventions as helpful compared to participants with ME/CFS. In contrast, participants with ME/CFS reported a significantly broader engagement with diverse intervention modalities, particularly pacing (M = 2.73, SD = 0.80) and dietary supplements (M = 2.43, SD = 1.09), and perceived many of them as helpful. Group differences remained significant after controlling for age, gender, and whether treatment was medically recommended. Supplements targeting energy metabolism (e.g., CoQ10, NADH) were especially favored among ME/CFS participants.

Conclusions: Findings suggest that participants with ME/CFS tend to adopt an exploratory and expansive intervention approach, potentially reflecting the lack of standardized guidelines and limited effectiveness of available treatment options. Participants with depression, in contrast, appeared to follow more guideline-concordant, evidence-based treatment pathways. Taken together, the findings point to a need for further development and evaluation of empirically supported, patient-centered treatment and intervention strategies for ME/CFS and suggest differences in clinical care structures between ME/CFS and depression.

Source: Dorczok MC, Mossaheb N, Mittmann G, Thomas MF, Bartova L, Schrank B, Steiner-Hofbauer V. Use and Perceived Helpfulness of Different Intervention Strategies in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Depression. J Clin Med. 2026 Jan 20;15(2):849. doi: 10.3390/jcm15020849. PMID: 41598786. https://www.mdpi.com/2077-0383/15/2/849 (Full text)

Relationships between fatigue, cognitive function, and upright activity in a randomized trial of oxaloacetate for myalgic encephalomyelitis/chronic fatigue syndrome

Abstract:

Background: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating condition characterized by fatigue, cognitive impairment, and reduced physical function. Oxaloacetate (OAA), a metabolic compound with potential mitochondrial and neuroprotective effects, has shown promise in reducing fatigue symptoms in ME/CFS. However, the interrelationships between fatigue, cognitive performance, and physical activity and their responsiveness to treatment remain poorly understood in ME/CFS.

Methods: This 90-day randomized, double-blind, controlled trial evaluated the effects of 2,000 mg/day OAA or a control of 2,000 mg rice flour in 82 adults with ME/CFS. Self-reported fatigue (Chalder Fatigue Questionnaire), cognitive function (DANA Brain Vital), and upright activity time (UP Time) were assessed at baseline and three follow-up visits. Linear mixed-effects models examined associations between fatigue severity and cognitive/physical function, with treatment group interactions. Responder status at the last visit (Visit 4) was classified based on ≥15% fatigue reduction and/or ≥10% cognitive improvement.

Results: The OAA group showed greater cognitive improvement over time, with a significant between-group difference at Visit 3, 60 days into the trial, (p = 0.034) and trends at other visits. Higher fatigue was significantly associated with reduced cognitive gains in the OAA group (β = −0.34, p < 0.0001), but not in controls. UP Time increased modestly in the OAA group, reaching significance at Visit 2, day 30 (p = 0.044), though fatigue was not a strong predictor of UP Time in either group. At Visit 4, day 90, Global and Fatigue Only Responders were more frequent in the OAA group, while Cognitive Only Responders were more frequent in controls, though group differences did not reach statistical significance (p = 0.10).

Conclusion: OAA supplementation was associated with improved cognitive performance and small improvement in UP Time in ME/CFS participants receiving OAA. Fatigue–cognition coupling was particularly strong in OAA-treated participants, suggesting a potentially targetable phenotype. These findings underscore the importance of multidimensional outcome measures in ME/CFS clinical trials and support the need for more research and trials of metabolic interventions in ME/CFS.

Source: Vernon Suzanne D. , Rond Candace , Sun Yifei , Roundy Shad , Bell Jennifer , Rond Bella , Kaufman David L. , Cash Alan B. , Yellman Brayden , Bateman Lucinda. Relationships between fatigue, cognitive function, and upright activity in a randomized trial of oxaloacetate for myalgic encephalomyelitis/chronic fatigue syndrome. Frontiers in Neurology, Volume 16 – 2025. DOI=10.3389/fneur.2025.1691147 ISSN=1664-2295 https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2025.1691147/full (Full text)

Nutraceutical Supplementation Effects on Subjective Fatigue Symptoms in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Systematic Review

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating condition marked by severe, long-lasting fatigue and exhaustion that does not improve with rest. ME/CFS is reported in individuals of all ages and various racial, socioeconomic, and ethnic groups. This condition lacks standard treatment. Nutritional supplements and dietary interventions are often used to manage symptoms, but the efficacy of these interventions remains scarce in the current literature. This systematic review aims to evaluate and summarize recent evidence on nutrient supplementation and diet-based interventions in patients with ME/CFS sourced from clinical trial registries and article databases.

Registries improve the quality, integrity, and transparency of clinical trials by providing a standardized platform for reporting study design and results and, thus, reducing the biases related to selective reporting practices. Systematic reviews using these registries, therefore, are an efficient pathway to acquire current medical evidence for use in clinical decision-making and the development of practice guidance in various fields. ClinicalTrials.gov, Medline, PubMed, Cochrane, and Web of Science were systematically searched for interventional studies in which patients suffering from ME/CFS supplemented or altered their diet.

The results of this review showed several supplements that suggest improvement in patients’ symptomatology, including nicotinamide adenine dinucleotide (NADH), coenzyme Q10 (CoQ10), wasabi, and probiotics. However, many of these registered clinical trials did not employ the U.S. National Institutes of Health (NIH)’s National Institute of Neurological Disorders and Stroke (NINDS) suggested common data elements (CDEs). These standardized outcome-measuring tools allow the generalization and true comparison of the patient-reported outcomes.

Source: Brito EM, Bonifanti L, Patel R, Jimenez J, Junco J, Rozenfeld IR, Renesca V, Cheema AK. Nutraceutical Supplementation Effects on Subjective Fatigue Symptoms in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Systematic Review. Cureus. 2025 Jul 2;17(7):e87178. doi: 10.7759/cureus.87178. PMID: 40755709; PMCID: PMC12315604. https://pmc.ncbi.nlm.nih.gov/articles/PMC12315604/ (Full text)

Efficacy of vitamin D replacement therapy on 28 cases of myalgic encephalomyelitis/chronic fatigue syndrome after COVID-19 vaccination

Abstract:

Background: Prolonged symptoms have been reported following both COVID-19 infection and vaccination, with some cases leading to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Of 80 patients presenting to our hospital with postvaccination syndrome, 28 met the diagnostic criteria for ME/CFS. We conducted a retrospective study on these 28 patients.

Methods: We measured serum 25-hydroxyvitamin D levels in 28 patients who developed ME/CFS after COVID-19 vaccination between August 2022 and February 2024. Vitamin D replacement therapy included dietary counseling, sun exposure recommendations, and oral vitamin D supplementation. We evaluated changes in blood vitamin D levels and symptom improvement.

Results: At initial visit, 27 of 28 patients diagnosed with ME/CFS had insufficient or deficient serum 25-hydroxyvitamin D levels (16 ± 4 ng/mL, mean ± SD). Following vitamin D replacement therapy, we observed an increase in blood vitamin D levels (28 ± 5 ng/mL) associated with a decrease in ME/CFS diagnostic symptoms (from 10.3 ± 2.1 to 3.3 ± 2.0). Notably, 23 of 28 patients (82%) no longer met ME/CFS diagnostic criteria after the therapy. Among the symptoms, sleep problems showed the most improvement (71%), followed by autonomic symptoms (68%).

Conclusions: For patients developing ME/CFS after COVID-19 vaccination with insufficient or deficient vitamin D levels, appropriate vitamin D replacement therapy under medical guidance may lead to symptomatic relief. We are preparing a randomized controlled trial to evaluate the efficacy of vitamin D replacement therapy in individuals with ME/CFS who have developed vitamin D deficiency following COVID-19 infection or vaccination.

Source: Kodama S, Konishi N, Hirai Y, Fujisawa A, Nakata M, Teramukai S, Fukushima M. Efficacy of vitamin D replacement therapy on 28 cases of myalgic encephalomyelitis/chronic fatigue syndrome after COVID-19 vaccination. Nutrition. 2025 Feb 18;134:112718. doi: 10.1016/j.nut.2025.112718. Epub ahead of print. PMID: 40090177. https://www.sciencedirect.com/science/article/pii/S089990072500036X (Full text)

Dietary Supplementation for Fatigue Symptoms in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)-A Systematic Review

Abstract:

Background/Objectives: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex neuroimmunological disorder with limited treatment options. Despite the widespread use of Dietary Supplements (DSs) among ME/CFS patients to alleviate fatigue and associated symptoms, evidence remains inconclusive. This systematic review aims to provide an updated synthesis of the efficacy of DS interventions and explore possible mechanisms underlying their therapeutic effects.

Methods: This systematic review was conducted according to PRISMA guidelines. Several databases (Ebsco Host, PubMed, Scopus, Google Scholar) were used for the systematic search, which was based on the broad search terms ME/CFS and DS with a focus on publications between 1994 and 2024. The primary outcome was fatigue, with additional considerations including psychological well-being, physical activity, and biochemical markers. Two independent researchers screened the studies for eligibility in a multi-stage process and assessed quality and bias using Cochrane’s risk of bias tools (RoB-2, ROBINS-I).

Results: Fourteen studies (N = 809) of heterogeneous designs were included, showing a high risk of bias, mostly due to missing data and selection bias. While some interventions (L-carnitine and guanidinoacetic acid, oxaloacetate, CoQ10-selenium combination, NADH and NADH-CoQ10 combination) showed significant reductions in fatigue, methodological limitations, like small sample sizes and missing data, prevent firm conclusions. Mixed results were reported for secondary outcomes like cognitive function and inflammatory markers. Six studies noted adverse effects, including nausea and insomnia.

Conclusions: Though some DSs showed potential in reducing fatigue in ME/CFS, methodological limitations and inconsistent results hinder definitive conclusions. Future research should improve diagnostic criteria and include more diverse populations.

Source: Dorczok MC, Mittmann G, Mossaheb N, Schrank B, Bartova L, Neumann M, Steiner-Hofbauer V. Dietary Supplementation for Fatigue Symptoms in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)-A Systematic Review. Nutrients. 2025 Jan 28;17(3):475. doi: 10.3390/nu17030475. PMID: 39940333; PMCID: PMC11819863. https://pmc.ncbi.nlm.nih.gov/articles/PMC11819863/ (Full text)

The effects of 3-month supplementation with synbiotic on patient-reported outcomes, exercise tolerance, and brain and muscle metabolism in adult patients with post-COVID-19 chronic fatigue syndrome (STOP-FATIGUE): a randomized Placebo-controlled clinical trial

Abstract:

Purpose: Considering the observed gastrointestinal issues linked to post-COVID-19 myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), beneficially modulating the gut microbiota could offer a safe, cost-effective nutritional strategy. This trial aimed to evaluate the effects of medium-term synbiotic supplementation on patient-reported outcomes, exercise tolerance, and tissue metabolism in patients with post-COVID-19 ME/CFS.

Methods: Between September 2022 and December 2023, we investigated the impact of 3-month supplementation with a synbiotic mixture including L. rhamnosus DSM 32550, Humiome® L. plantarum DSM 34532, B. lactis DSM 32269, B. longum DSM 32946, fructooligosaccharides and zinc, on predetermined primary and secondary outcome measures in twenty six post-COVID-19 ME/CFS patients utilizing a parallel-group, randomized, placebo-controlled, double-blind design.

Results: Both the synbiotic and placebo intake resulted in a significant reduction in general fatigue after 3 months compared to the baseline values (P ≤ 0.05). This was accompanied by a significant interaction effect (time vs. treatment) for post-exercise malaise (P = 0.02), with synbiotic superior to placebo to attenuate post-exercise malaise. The synbiotic also demonstrated a significant advantage over placebo in increasing choline levels at the thalamus (P = 0.02), and creatine levels at left frontal white matter (P = 0.05) and left frontal grey matter (P = 0.04).

Conclusion: Taking the synbiotic mixture for three months improves tissue metabolism and mitigates clinical features of post-COVID-19 fatigue syndrome. The presented data show promise in addressing the widespread issue of ME/CFS following the COVID-19 pandemic; however, further validation is needed before endorsing the synbiotics within this clinical context. The study is registered at ClinicalTrials.gov (NCT06013072).

Source: Ranisavljev M, Stajer V, Todorovic N, Ostojic J, Cvejic JH, Steinert RE, Ostojic SM. The effects of 3-month supplementation with synbiotic on patient-reported outcomes, exercise tolerance, and brain and muscle metabolism in adult patients with post-COVID-19 chronic fatigue syndrome (STOP-FATIGUE): a randomized Placebo-controlled clinical trial. Eur J Nutr. 2024 Nov 26;64(1):28. doi: 10.1007/s00394-024-03546-0. PMID: 39592468. https://pubmed.ncbi.nlm.nih.gov/39592468/

Six-Week Supplementation with Creatine in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): A Magnetic Resonance Spectroscopy Feasibility Study at 3 Tesla

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic medical condition with no specific pharmacological treatment. Creatine, a nutrient essential for maintaining energy homeostasis in the cells, is a candidate for interventions in ME/CFS.

Methods: Fourteen participants with ME/CFS received supplementation with 16 g creatine monohydrate for 6 weeks. Before starting creatine and on the last day of treatment, participants underwent brain magnetic resonance spectroscopy (MRS) scanning of the pregenual anterior cingulate cortex (pgACC) and dorsolateral prefrontal cortex (DLPFC), followed by symptom, cognition, and hand-grip strength assessments.

Results: Eleven participants completed the study. Creatine treatment increased creatine concentration in both the pgACC and DLPFC (p = 0.004 and 0.012, respectively), decreased fatigue and reaction time (RT) on congruent and incongruent trials of the Stroop test (p = 0.036 and 0.014, respectively), and increased hand-grip strength (p = 0.0004). There was a positive correlation between increases in pgACC creatine and changes in RT on Stroop congruent and incongruent trials (p = 0.048 and p = 0.022, respectively). Creatine was well tolerated, and none of the participants stopped treatment.

Conclusion: Creatine supplementation over six weeks in ME/CFS patients increased brain creatine and improved fatigue and some aspects of cognition. Despite its methodological limitations, this study encourages placebo-controlled investigations of creatine treatment in ME/CFS.

Source: Godlewska BR, Sylvester AL, Emir UE, Sharpley AL, Clarke WT, Martens MAG, Cowen PJ. Six-Week Supplementation with Creatine in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): A Magnetic Resonance Spectroscopy Feasibility Study at 3 Tesla. Nutrients. 2024 Sep 30;16(19):3308. doi: 10.3390/nu16193308. PMID: 39408275. https://www.mdpi.com/2072-6643/16/19/3308 (Full text)

A Narrative Review on Gut Microbiome Disturbances and Microbial Preparations in ME/CFS: Implications for Long COVID

Abstract:

Myalgic Encephalomyelitis, also known as Chronic Fatigue Syndrome (ME/CFS) and Long COVID are characterized by debilitating post-exertional malaise and other core symptoms related to immune dysregulation resultant from post-viral infection, including mitochondrial dysfunction, chronic neuroinflammation and gut dysbiosis. The reported associations between altered microbiota composition and cardinal symptoms of ME/CFS and Long COVID, suggesting that use of microbial preparations, such as probiotics, by restoring the homeostasis of the brain-immune-gut axis may help in the management of symptoms in both conditions.

Therefore, this review aims to investigate the implications of alerted gut microbiome and assess the evidence supporting use of microbial-based preparations, including probiotics, synbiotics, postbiotics alone and/or in combination with other nutraceuticals in the management of fatigue, inflammation, as well as neuropsychiatric and gastrointestinal symptoms among patients with ME/CFS and Long COVID.

Source: Jurek, J.M.; Castro-Marrero, J. A Narrative Review on Gut Microbiome Disturbances and Microbial Preparations in ME/CFS: Implications for Long COVID. Preprints 2024, 2024042021. https://doi.org/10.20944/preprints202404.2021.v1  https://www.preprints.org/manuscript/202404.2021/v1 (Full text available as PDF file)