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The Influence of n-3PUFA Supplementation on Muscle Strength, Mass, and Function: A Systematic Review and Meta-Analysis.
Santo André, HC, Esteves, GP, Barreto, GHC, Longhini, F, Dolan, E, Benatti, FB
Advances in nutrition (Bethesda, Md.). 2023;14(1):115-127
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Omega 3 polyunsaturated fatty acids (n-3PUFA) are long-chain polyunsaturated fatty acids essential to human health. They play a role in cell membrane integrity, immune and inflammation regulation, cognition and neuromuscular function. As the human body cannot make these fatty acids, they need to be obtained through diet or supplementation. Regarding skeletal muscle, recent research showed that n-3PUFAs may increase the uptake of amino acids by increasing the membrane fluidity in the muscle, and by activating pathways that inhibit protein breakdown. This led to the hypothesis that n-3PUFAs may enhance muscle mass gain and strength. This systematic review sought to gather all available evidence about the impact of n-3PUFA supplementation on muscle mass, strength, and function in healthy young and older adults. The review included 14 studies with a total of 1443 participants. The authors found that n-3PUFA supplementation had no significant effect on muscle mass or muscle function in healthy young and older adults, however, a very small but significant positive effect was noted regarding muscle strength. In the discussion section, the authors explain the challenges of their review and how these findings integrate with the current understanding and other research findings. They concluded more research is needed to get a better insight into the effects of n-3PUFA on muscle function and the variants.
Abstract
The effects of omega 3 polyunsaturated fatty acids (n-3PUFA) supplementation on skeletal muscle are currently unclear. The purpose of this systematic review was to synthesize all available evidence regarding the influence of n-3PUFA supplementation on muscle mass, strength, and function in healthy young and older adults. Four databases were searched (Medline, Embase, Cochrane CENTRAL, and SportDiscus). Predefined eligibility criteria were determined according to Population, Intervention, Comparator, Outcomes, and Study Design. Only peer-reviewed studies were included. The Cochrane RoB2 Tool and the NutriGrade approach were used to access risk of bias and certainty in evidence. Effect sizes were calculated using pre-post scores and analyzed using a three-level, random-effects meta-analysis. When sufficient studies were available, subanalyses were performed in the muscle mass, strength, and function outcomes according to participant's age (<60 or ≥60 years), supplementation dosage (<2 or ≥2 g/day), and training intervention ("resistance training" vs. "none or other"). Overall, 14 individual studies were included, total 1443 participants (913 females; 520 males) and 52 outcomes measures. Studies had high overall risk of bias and consideration of all NutriGrade elements resulted in a certainty assessment of moderate meta-evidence for all outcomes. n-3PUFA supplementation had no significant effect on muscle mass (standard mean difference [SMD] = 0.07 [95% CI: -0.02, 0.17], P = 0.11) and muscle function (SMD = 0.03 [95% CI: -0.09, 0.15], P = 0.58), but it showed a very small albeit significant positive effect on muscle strength (SMD = 0.12 [95% CI: 0.006, 0.24], P = 0.04) in participants when compared with placebo. Subgroup analyses showed that age, supplementation dose, or cosupplementation alongside resistance training did not influence these responses. In conclusion, our analyses indicated that n-3PUFA supplementation may lead to very small increases in muscle strength but did not impact muscle mass and function in healthy young and older adults. To our knowledge, this is the first review and meta-analysis investigating whether n-3PUFA supplementation can lead to increases in muscle strength, mass, and function in healthy adults. Registered protocol: doi.org/10.17605/OSF.IO/2FWQT.
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Absence of Effects of L-Arginine and L-Citrulline on Inflammatory Biomarkers and Oxidative Stress in Response to Physical Exercise: A Systematic Review with Meta-Analysis.
Porto, AA, Gonzaga, LA, Benjamim, CJR, Valenti, VE
Nutrients. 2023;15(8)
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L-citrulline is a non-essential amino acid that acts as a precursor to L-arginine. L-arginine is a semi-essential amino acid used for nitric oxide production which is crucial for maintaining physiological function and immune regulation. Previous research has shown that L-citrulline and L-arginine supplementation may offer antioxidant and anti-inflammatory benefits in reducing exercise-related oxidative stress and inflammation. This systematic review and meta-analysis included seven randomised controlled trials to investigate the effect of L-citrulline and L-arginine on antioxidants, oxidative stress, and inflammatory and anti-inflammatory markers. This systematic review and meta-analysis showed no significant improvements in oxidative stress and inflammation followed by the supplementation of L-citrulline and L-arginine before exercise. However, further robust studies that include different dosages and exercise intensities are required to assess the beneficial effects of L-citrulline and L-arginine supplements to support physical exercise-induced oxidative stress and inflammation due to the heterogeneity of the included studies. Healthcare professionals can use the results of this study to understand the potential benefits of L-citrulline and L-arginine supplementation in people prone to producing proinflammatory cytokines.
Abstract
The repercussions on oxidative and inflammatory stress markers under the effects of arginine and citrulline in response to exercise are not fully reached. We completed a systematic review to investigate the effects of L-Citrulline or L-Arginine on oxidative stress and inflammatory biomarkers following exercise. EMBASE, MEDLINE (PubMed), Cochrane Library, CINAHL, LILACS, and Web of Science databases were used to record the trials. This study includes randomized controlled trials (RCTs) and non-RCTs with subjects over 18 years old. Those under the intervention protocol consumed L-Citrulline or L-Arginine, and the controls ingested placebo. We recognized 1080 studies, but only 7 were included (7 studies in meta-analysis). We observed no difference between pre- vs. post-exercise for oxidative stress (subtotal = -0.21 [CI: -0.56, 0.14], p = 0.24, and heterogeneity = 0%. In the sub-group "L-Arginine" we found a subtotal = -0.29 [-0.71, 0.12], p = 0.16, and heterogeneity = 0%. For the "L-Citrulline" subgroup we observed a subtotal = 0.00 [-0.67, 0.67], p = 1.00, and heterogeneity was not applicable. No differences were observed between groups (p = 0.47), and I² = 0%) or in antioxidant activity (subtotal = -0.28 [-1.65, 1.08], p = 0.68, and heterogeneity = 0%). In the "L-Arginine" sub-group, we found a subtotal = -3.90 [-14.18, 6.38], p = 0.46, and heterogeneity was not applicable. For the "L-Citrulline" subgroup, we reported a subtotal = -0.22 [-1.60, 1.16], p = 0.75, and heterogeneity was not applicable. No differences were observed between groups (p = 0.49), and I² = 0%), inflammatory markers (subtotal = 8.38 [-0.02, 16.78], p = 0.05, and heterogeneity = 93%. Tests for subgroup differences were not applicable, and anti-inflammatory markers (subtotal = -0.38 [-1.15, 0.39], p = 0.34 and heterogeneity = 15%; testing for subgroup differences was not applicable). In conclusion, our systematic review and meta-analysis found that L-Citrulline and L-Arginine did not influence inflammatory biomarkers and oxidative stress after exercise.
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Impact of Probiotics on the Performance of Endurance Athletes: A Systematic Review.
Díaz-Jiménez, J, Sánchez-Sánchez, E, Ordoñez, FJ, Rosety, I, Díaz, AJ, Rosety-Rodriguez, M, Rosety, MÁ, Brenes, F
International journal of environmental research and public health. 2021;18(21)
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The relationship between the gut microbiome and exercise has recently been explored to ascertain potential methods of improving athletic performance. Athletes have begun utilising probiotics to improve performance, support the immune system and reduce gastrointestinal problems, however no systematic review has been done to assess the efficacy behind these notions. The aim of this study is to review the use of probiotics in endurance athletes and assess both the direct and indirect associative factors. This review included nine studies and found improvements in athletic performance, oxidative stress markers, immune support, and incidence of upper respiratory tract infections with probiotic use. While there is little scientific evidence on the causative relationship between probiotics and performance, the authors conclude probiotics can enhance athletic performance by ameliorating the indirect consequences of oxidative stress and infection.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Endurance athletes may take probiotic supplements to support immune or GI health or for other reasons
- Currently there is little evidence that probiotics directly or specifically enhance athletic performance
- Probiotic supplementation potentially impacts on immune health particularly during intensive training and may facilitate muscle recovery or maintain performance
- Whilst probiotics may reduced GI symptom frequency and severity, further research is clearly warranted
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
- There is current interest in the potential therapeutic benefits of probiotic strategies to support training and in-race performance for endurance athletes.
- Probiotic supplements are typically used by endurance athletes to limit or prevent upper respiratory tract infections (URTIs), reduce oxidative stress, support the immune system and modulate gastrointestinal function.
- Based on a limited number of articles sourced in this review (n=26), only 9 met the underlying quality and inclusion criteria. This highlights an important need for further research to be undertaken in this area.
- The review highlighted that different preparations, number of bacterial colony-forming units (CFUs), species type, timecourse and study objectives makes it difficult to determine fundamental conclusions on the efficacy of probiotics.
- That said, papers reviewed indicated the potential for a 55% increase in anti-inflammatory cytokines, reduced prevalence of URTIs, reduced Epstein-Barr and cytomegalovirus citrate antibodies, and improved recovery times.
- Probiotic supplementation likely enhances microbiota diversity and may indirectly support increased training load, and performance maintenance through immune defence. However, there were no indications that endurance performance was specifically enhanced.
Clinical practice applications:
- Most of the papers reviewed used formulae containing either Lactobacillus spp. (e.g. Plantarum, Acidophilus, Casei Shirota) or Bifidobacterium spp. (e.g. animalis subsp., bifidum, lactis, longum subsp.) or combinations. There was little mention of prebiotic or symbiotic strategies.
- Any impact of probiotics on exercise performance is likely to relate to both immune modulation and/or mechanisms leading to reduced muscle damage.
- Surprisingly, there was only partial mention of the use of probiotics for GI support and several notable papers were not included in the review. That said, the authors did note that with increased prevalence of exercise-induced gastrointestinal symptoms with endurance sport due to acute GI hypoperfusion and localised ischemia, acute probiotic strategies have resulted in reduced GI symptom frequency and severity in athletes.
- Importantly no adverse events following probiotic supplementation in endurance athletes were reported.
Considerations for future research:
- Clearly further research is warranted in terms of probiotic strain specific benefits both in training and in-race event effectiveness.
- The authors reported that there were no studies found on the effect of probiotics on hormonal or nervous systems in endurance athletes.
- Further research is needed to consider the impact of acute versus chronic probiotic use on intestinal metabolites, especially considering recent interactions between specific bacterial strains and short-chain fatty acid production being associated with performance (see: https://www.nutrition-evidence.com/article/31235964?term=31235964.
Abstract
BACKGROUND Probiotic supplements contain different strains of living microorganisms that promote the health of the host. These dietary supplements are increasingly being used by athletes to improve different aspects such as athletic performance, upper respiratory tract infections (URTIs), the immune system, oxidative stress, gastrointestinal (GI) problems, etc. This study aimed to identify the current evidence on the management of probiotics in endurance athletes and their relationship with sports performance. METHODS A systematic review of the last five years was carried out in PubMed, Scopus, Web of science, Sportdiscus and Embase databases. RESULTS Nine articles met the quality criteria. Of these, three reported direct benefits on sports performance. The remaining six articles found improvements in the reduction of oxidative stress, increased immune response and decreased incidence of URTIs. There is little scientific evidence on the direct relationship between the administration of probiotics in endurance athletes and sports performance. CONCLUSIONS Benefits were found that probiotics could indirectly influence sports performance by improving other parameters such as the immune system, response to URTIs and decreased oxidative stress, as well as the monitoring of scheduled workouts.
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Nutrition, the digestive system and immunity in COVID-19 infection.
Bold, J, Harris, M, Fellows, L, Chouchane, M
Gastroenterology and hepatology from bed to bench. 2020;13(4):331-340
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Covid-19 needs both prevention and recovery strategies to reduce complications. This review study aimed to discuss the associations between nutrition, obesity, and the impact these have on stomach symptoms associated with Covid-19. Obesity has been identified as a risk factor for Covid-19 and this could be due to several factors such as impaired immune function, increased inflammation, increased susceptibility to infection and the high number of cells on fat tissue, which express the receptor known to allow Covid-19 into cells. The involvement of the gut microbiota of obese individuals was extensively reviewed and gut dysbiosis has been associated with many diseases, thus improving gut microbiota may go some way to improving Covid-19 outcomes. Nutritional interventions to reduce obesity need to be part of a multi-pronged strategy and the possible introduction of vitamin D supplements and probiotics. The paper did not draw any conclusions; however this paper could be used by healthcare professionals to understand the role of obesity in increasing the risk of Covid-19 infection, complications that may arise upon and after infection and nutritional strategies as part of a management plan.
Abstract
The current review aimed to synthesize the literature on the complex relationship between food consumption and nutritional status as well as the digestive system in order to examine the relationship between immunity and potential responses to COVID-19 infection. The goal is to help inform the many healthcare professionals working with COVID-19 patients. A literature search was performed on PubMed, Scopus, and EMBASE databases. Hand searches were also undertaken using Google and reference lists to identify recent evidence. Studies were critically appraised, and the findings were analyzed by narrative synthesis. Nutritional status can impact immunity in several ways, including affecting susceptibility to infection, severity of disease, and recovery time, and is therefore a significant consideration in the management of COVID-19. COVID-19 can also impact digestive function, which can further impact nutritional status. The role of Vitamin D deficiency in vulnerability to severe respiratory infections, including COVID-19, has been recognized, and it may have a role in treatment where deficiency is indicated. Healthcare professionals should be aware that obesity may be accompanied by micronutrient malnutrition including vitamin D deficiency and alterations in the microbiome and inflammatory responses, which can further impact immunity and disease severity. Multidisciplinary team-work is recommended in the management of patients with COVID-19, and approaches should include a consideration of nutritional status (both macronutrients and micronutrients), body weight, and gastrointestinal signs and symptom.
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COVID-19 and diabetes: The why, the what and the how.
Cuschieri, S, Grech, S
Journal of diabetes and its complications. 2020;34(9):107637
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Early reports have shown that individuals with diabetes who contract Covid-19 have higher hospital admissions and mortality rates, classing them as a vulnerable group. This review paper aimed to explain why this group of people are vulnerable and what measures could be recommended. The paper outlined that individuals with diabetes have a compromised immune system due to uncontrolled blood sugar levels. In addition to this, individuals with diabetes and Covid-19 may have a higher risk of organ damage due to the effects of the body's immune response combined with the disordered biological processes associated with their pre-existing condition. Conversely, it was discussed that Covid-19 could exacerbate diabetes progression if the Covid-19 virus entered the cells of the pancreas, causing a blood sugar imbalance. As a result, the importance of optimal blood sugar control was outlined. Several medications were addressed and their benefits/disadvantages discussed. Amongst those reviewed were medications such as GLP-1 agonists, which may help with controlling blood sugar levels and may prevent Covid-19 entering the body's own cells, and metformin, which was initially developed as an anti-influenza drug. Finally the paper discussed diabetes specific precautions to avoid contracting Covid-19. Vitamin D supplementation, regular blood sugar checks, lifestyle measures such as exercise and dietary requirements and allowing individuals with diabetes to have large supplies of their medications to avoid leaving the house were discussed. It was concluded that during the Covid-19 pandemic, individuals with diabetes require particular care in order to avoid additional burden on healthcare systems. For those individuals with diabetes who haven’t contracted Covid-19, this paper could be used to recommend any extra precautions to take to avoid contracting this virus.
Abstract
BACKGROUND The novel coronavirus SARS-CoV-2 has taken the world by storm. Alongside COVID-19, diabetes is a long-standing global epidemic. The diabetes population has been reported to suffer adverse outcomes if infected by COVID-19. The aim was to summarise information and resources available on diabetes and COVID-19, highlighting special measures that individuals with diabetes need to follow. METHODS A search using keywords "COVID-19" and "Diabetes" was performed using different sources, including PubMed and World Health Organization. RESULTS COVID-19 may enhance complications in individuals with diabetes through an imbalance in angiotension-converting enzyme 2 (ACE2) activation pathways leading to an inflammatory response. ACE2 imbalance in the pancreas causes acute β-cell dysfunction and a resultant hyperglycemic state. These individuals may be prone to worsened COVID-19 complications including vasculopathy, coagulopathy as well as psychological stress. Apart from general preventive measures, remaining hydrated, monitoring blood glucose regularly and monitoring ketone bodies in urine if on insulin is essential. All this while concurrently maintaining physical activity and a healthy diet. Different supporting entities are being set up to help this population. CONCLUSION COVID-19 is a top priority. It is important to remember that a substantial proportion of the world's population is affected by other co-morbidities such as diabetes. These require special attention during this pandemic to avoid adding on to the burden of countries' healthcare systems.
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Antiviral Functional Foods and Exercise Lifestyle Prevention of Coronavirus.
Alkhatib, A
Nutrients. 2020;12(9)
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In lieu of a vaccine, complementary therapies have a major role to play in the Covid-19 pandemic. This review paper aimed to highlight how lifestyle approaches such as consumption of functional foods and increased physical activity could optimise the immune system in response to viral infections such as respiratory tract infections and Covid-19, and act as a possible adjuvant to vaccination. The paper outlined the role of exercise as being controversial. Although exercise has been shown to activate white blood cells, intense exercise in elite athletes has been linked to higher upper respiratory tract infection rates. It appears that varying intensity and type of exercise may optimise the immune system and have an additive effect to immunisation against viruses like influenza. The authors also stated that having a sedentary lifestyle may impair the immune system and diseases such as obesity and diabetes may increase susceptibility to infections such as Covid-19. The antiviral effect of functional foods was discussed. The paper paid particular attention to olive oil, vitamin D, traditional herbs and roots, coffee and caffeine. The reviewed mechanisms included enhanced gut bacteria profiles and promotion of anti-oxidants and anti-inflammatories. The authors also stated that supplementation as well as adequate dietary intake might be of importance against Covid-19, especially in deficient individuals. It was concluded that moderate intensity exercise alongside dietary intake of functional foods, may prevent communicable diseases, such as Covid-19. Clinicians could use this paper to recommend specific functional foods plus moderate exercise, to help prevent viral infections like Covid-19.
Abstract
Novel coronavirus (COVID-19) is causing global mortality and lockdown burdens. A compromised immune system is a known risk factor for all viral influenza infections. Functional foods optimize the immune system capacity to prevent and control pathogenic viral infections, while physical activity augments such protective benefits. Exercise enhances innate and adaptive immune systems through acute, transient, and long-term adaptations to physical activity in a dose-response relationship. Functional foods prevention of non-communicable disease can be translated into protecting against respiratory viral infections and COVID-19. Functional foods and nutraceuticals within popular diets contain immune-boosting nutraceuticals, polyphenols, terpenoids, flavonoids, alkaloids, sterols, pigments, unsaturated fatty-acids, micronutrient vitamins and minerals, including vitamin A, B6, B12, C, D, E, and folate, and trace elements, including zinc, iron, selenium, magnesium, and copper. Foods with antiviral properties include fruits, vegetables, fermented foods and probiotics, olive oil, fish, nuts and seeds, herbs, roots, fungi, amino acids, peptides, and cyclotides. Regular moderate exercise may contribute to reduce viral risk and enhance sleep quality during quarantine, in combination with appropriate dietary habits and functional foods. Lifestyle and appropriate nutrition with functional compounds may offer further antiviral approaches for public health.
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Coronavirus disease 2019 (COVID-19) and obesity. Impact of obesity and its main comorbidities in the evolution of the disease.
Cornejo-Pareja, IM, Gómez-Pérez, AM, Fernández-García, JC, Barahona San Millan, R, Aguilera Luque, A, de Hollanda, A, Jiménez, A, Jimenez-Murcia, S, Munguia, L, Ortega, E, et al
European eating disorders review : the journal of the Eating Disorders Association. 2020;28(6):799-815
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The Covid-19 pandemic has caused thousands of deaths worldwide. Being obese is associated with worse outcomes following infection with Covid-19. This review aimed to summarise the data available on the relationship between Covid-19 and obesity, and explored some of the possible reasons for this relationship. The researchers found that obesity is an independent and strong risk factor for severe infection, Intensive Care Unit (ICU) admission and death. The impact of obesity might be of particular relevance in males and in younger individuals. Long‐term complications of Covid‐19 could also be more frequent and severe in obese subjects. There are many potential mechanisms that could explain this relationship. These include the effects of obesity and related diseases such as diabetes, high blood pressure and heart disease on the immune system, lung function, vitamin D deficiency and male hormones. The researchers also discussed the possibility of fat cells acting as a possible reservoir for Covid-19 infection. Research into Covid-19 is still at a very early stage and more studies are needed.
Abstract
The COVID-19 pandemic is posing a great challenge worldwide. Its rapid progression has caused thousands of deaths worldwide. Although multiple aspects remain to be clarified, some risk factors associated with a worse prognosis have been identified. These include obesity and some of its main complications, such as diabetes and high blood pressure. Furthermore, although the possible long-term complications and psychological effects that may appear in survivors of COVID-19 are not well known yet, there is a concern that those complications may be greater in obese patients. In this manuscript, we review some of the data published so far and the main points that remain to be elucidated are emphasized.
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Danger signals and inflammaging in osteoarthritis.
Millerand, M, Berenbaum, F, Jacques, C
Clinical and experimental rheumatology. 2019;37 Suppl 120(5):48-56
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Osteoarthritis (OA) is the most common and disabling joint disease worldwide and aging is the most important risk factor for its development. It was considered a ‘wear and tear’ disease for a long time, however it is now clear that low-grade inflammation is at the root of OA. This process is called ‘inflammaging’ – the presence of low-grade inflammation and decreased efficiency of the immune system with aging. This highly technical review paper describes the reaction of the immune system to small molecules that begin to circulate after cell stress or damage in the joints (known as damage-associated molecular patterns or DAMPs), causing inflammation. The paper includes a discussion on potential medication targets, including anti-inflammatory compounds such as ginger. Nutrition Practitioners working with OA and wanting to understand the inflammatory process involved will find this paper useful.
Abstract
Osteoarthritis (OA) is the most common age-related chronic and disabling joint disease. Long considered to be a "wear and tear" disease, OA is now seen as a low-grade inflammation disease that affects all tissues of the joint, involving cartilage degradation, bone remodelling, osteophytes, and synovitis. The process, called inflammaging, is characterised by the association of low-grade inflammation, profound changes in intra-cellular mechanisms, and the decreased efficiency of the immune system with ageing. The activation of innate immunity plays a critical role in the development and progression of OA. Innate immunity, including inflammasome activation, is triggered by small endogenous molecules called alarmins or damage-associated molecular patterns (DAMPs). These molecules are released in the extracellular media after cell stress or damage, bind to pathogen-recognition receptors (PRRs), such as Toll-like receptors (TLRs) and the receptor for advanced glycation end products (RAGE), and activate the secretion of pro-inflammatory factors, leading to joint inflammation. Moreover, such sterile inflammation triggers cell senescence, characterised by a senescence-associated secretory phenotype (SASP). Understanding the substantial age-related changes of joint tissues that influence the pathogenesis of OA is critical to improving the quality of life of elderly people in the context of increased life expectancy. This review will focus on age-related sterile inflammation in OA and highlight the various innovative and promising therapies targeting the mechanisms of aging.