ENDOTARGET publication: Beyond Seasoning – The Role of Herbs and Spices in Rheumatic Diseases

Sofia Charneca, Ana Hernando, Patrícia Costa-Reis and Catarina Sousa Guerreiro 

2023, Nutrients

 

Background and Objectives: 

Although we have witnessed remarkable progress in understanding the biological mechanisms that lead to the development of rheumatic diseases (RDs), remission is still not achieved in a substantial proportion of patients with the available pharmacological treatment. As a consequence, patients are increasingly looking for complementary adjuvant therapies, including dietary. The potential benefits of herbs and spices have been investigated in various RDs, both in animal models and human trials. This study aims to provide an up-to-date review of the mechanisms whereby herbs and spices may be of interest in Rheumatoid Arthritis (RA), Osteoarthritis (OA), and Fibromyalgia (FM) as well as summarise human studies investigating their effects in these conditions. 

 

Results: 

The Crosstalk between Diet, Gut Microbiota, and Rheumatic Diseases 

Strong rationale suggests that dietary compounds and patterns may be related to pathways involved in inflammation and autoimmunity in RA. Growing experimental and clinical evidence suggests that gut dysbiosis may induce a chronic inflammatory response that could be linked to RA disease development. One of the proposed mechanisms whereby dietary interventions may influence RA is through the modulation of intestinal microbiota and intestinal barrier function. Anti-inflammatory diets, including the Mediterranean Diet, vegetarian, and vegan diets have already been shown to result in a significantly lower subjective pain rating by RA patients, when compared to ordinary diets. 

Insights into the Bioactive Properties of Herbs and Spices and Proposed Mechanisms Whereby They May Be of Interest in Rheumatology

The therapeutic potential of herbs and spices has been investigated for several diseases, including RDs. Increasing evidence highlights their richness in bioactive molecules such as sulfur-containing compounds, tannins, alkaloids, phenolic diterpenes, and vitamins, especially flavonoids and polyphenols, together with their antioxidant, anti-inflammatory, antitumorigenic, and anticarcinogenic properties. Especially cinnamon, curcumin, garlic, turmeric and saffron contain a variety of bioactive compounds that can affect health positively in different forms, e.g. by anti-inflammatory properties.
Furthermore, evidence suggests that substrates present in herbs and spices can drive favorable changes in gut communities and contribute to their proposed health-related effects. For instance, both cinnamon and ginger were shown to be able to enhance intestinal barrier function and modulate gut microbiota in animal models. Studies have also highlighted a bidirectional interaction between curcumin and its metabolites and microbiota, that is, the regulation of gut microbiota by curcumin and the biotransformation of curcumin by the gut microbiota.
Overall, these findings highlight the importance of exploring the role of gut microbiota as a mechanism whereby dietary interventions may be relevant in RDs. Gut microbiota, among other factors, may play a role in the initiation and progression of inflammation-driven diseases. The interplay between gut microbiota and the host immune system is reported to be relevant for balancing and resolving inflammation and may represent a potential therapeutic strategy 

Experimental Evidence from Human Studies on Herbs and Spices in RD 

RA – In total, the effect of herbs and spices on RA patients was investigated in 10 different human trials with cinnamon, curcumin, garlic, ginger and saffron. The studies showed that herbs and spices may play a role in improving disease activity and the immunological and inflammatory status of RA patients. 

OA – Spices, especially curcuminoids, have been increasingly studied in human trials as a natural treatment option for inflammatory and pain-related symptoms in patients suffering from OA. It has been shown in several studies that curcumin treatment does positively influence subjective symptoms of OA (pain, stiffness, physical constitution), but also objective biomarker levels. Next to curcuminoids, saffron and garlic were also shown to have potential anti-inflammatory and immunoregulatory effects on patients with OA. 

FM – In general, the quality of evidence for the effects of spices and herbs on FM patients is limited due to the poor number of randomised controlled trials (RCTs) available and due to the small sample sizes. Nevertheless, available studies show that herbs and spices can have a positive impact on FM. For instance, saffron was shown to have the same effects as duloxetine, which is commonly used to treat depressive symptoms, which are common in patients with FM. This fits the finding that saffron has similar efficacy to serotonin and norepinephrine reuptake inhibitors for the treatment of depression. 

Overall, some studies have shown the beneficial effects of herbs and spices in both objective and subjective measures. Nevertheless, the available RCTs have a high risk of bias, and more research is required to be able to clearly define the health benefits of herbs and spices. Although the current evidence is exciting, clinicians should interpret these results with caution before translating this knowledge into clinical practice. There are several limitations that have to be considered for clinical practice. 

 

Conclusion:

This review explores the role of herbs and spices in RDs, as well as the link between these complex disorders, inflammation, and gut microbiota. Although the results are promising, especially in the context of the many unmet needs of patients with RDs, the current evidence is insufficient to make recommendations. 

 

Read the full publication:  Beyond Seasoning—The Role of Herbs and Spices in Rheumatic Diseases

Glossary:

• Fibromyalgia (FM): a chronic condition characterised by widespread musculoskeletal pain, fatigue, and tenderness in localised areas. 
• Osteoarthritis (OA): a degenerative joint disease characterised by the breakdown of cartilage, leading to pain, swelling, stiffness, and reduced mobility in affected joints. 
• Randomised Controlled Trial (RCT): a scientific study that randomly assigns participants into an experimental group or a control group to compare the effects of a specific variable or treatment on an outcome. 
• Rheumatic Disease (RD): refers to a group of disorders affecting the joints, muscles, and connective tissues, characterised by inflammation and pain. 
• Rheumatoid Arthritis (RA): a chronic autoimmune disorder that primarily affects joints, causing inflammation, pain, stiffness, and eventually joint damage and deformity.