What is it about?

Virgin olive oil is the primary source of fat in the Mediterranean diet, and its beneficial health effects have been related with oleic acid and phenolic compounds content. Hydroxytyrosol, a typical virgin olive oil phenolic compound, has beneficial antioxidant and anti-inflammatory properties as previously reported. The aim of this study was to evaluate the effect of hydroxytyrosol-supplemented refined olive oil in a rodent model of rheumatoid arthritis. The treatment at 5-mg/kg dose significantly decreased paw edema (P<.01), histological damage, cyclooxygenase-2 and inducible nitric oxide synthase expression, and markedly reduced the degree of bone resorption, soft tissue swelling and osteophyte formation, improving articular function in treated animals. Acute inflammation, induced by carrageenan, was also evaluated for hydroxytyrosol-supplemented refined olive oils at 0.5 and 5 mg/kg. Both doses significantly reduced paw edema (P<.001). Results suggest that the supplementation of refined olive oil with hydroxytyrosol may be advantageous in rheumatoid arthritis with significant impact not only on chronic inflammation but also on acute inflammatory processes.

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Why is it important?

This study demonstrated that hydroxytyrosol supplementation significantly improved the severity of Rheumatoid Arthritis in the collagen-induced model in rats, down-regulating COX-2 and iNOS expression. Protective effects in acute inflammation can be achieved at 0.5 and 5 mg/kg hydroxytyrosol–ROO supplementation, and a higher anti-inflammatory activity than indomethacin, Trolox or tempol was identified, suggesting that hydroxytyrosol could be affecting multiple anti-inflammatory pathways. Further studies should proceed to further validate these hydrotyrosol effects in humans and under pathological conditions.


This work demonstrated the potential to supplement certain foods, such as olive oil, with a highly beneficial compound, to aid in combating certain ailments.

Dr. Rosa Direito
Universidade de Lisboa

Read the Original

This page is a summary of: Protective effects of hydroxytyrosol-supplemented refined olive oil in animal models of acute inflammation and rheumatoid arthritis, The Journal of Nutritional Biochemistry, April 2015, Elsevier, DOI: 10.1016/j.jnutbio.2014.11.011.
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