Rus A, Molina F, Martínez-Ramírez MJ, Aguilar-Ferrándiz ME, Carmona R, del Moral ML. Effects of olive oil consumption on cardiovascular risk factors in patients with fibromyalgia. Nutrients. March 27, 2020;12(4):918. doi: 10.3390/nu12040918.
Fibromyalgia (FM), characterized by diffuse chronic pain, is associated with poor sleep, fatigue, mental and physical disorders, and reduced quality of life. The usually-sedentary lifestyle of people with fibromyalgia is blamed for their 30% greater mortality risk vs. those who do not have FM. The etiology of FM is uncertain, and there is no accepted remedy. Treatment of symptoms is multidisciplinary, with physical, pharmacological, and cognitive elements. Tricyclic antidepressants, cardiovascular (CV) exercise, cognitive therapy, and patient education are most recommended. The authors have reported prothrombosis in patients with FM, with altered thrombosis-related markers that raise risks of CV disease (CVD).
The Mediterranean diet is associated with longer life and reduced risks for CVD, cancer, neurodegenerative diseases, and type 2 diabetes. Along with higher intake of fruits, vegetables, nuts, legumes, unprocessed grains, and fish, its generous olive (Olea europaea, Oleaceae) oil (OO) component is credited with its benefits. Many studies report OO's cardioprotective, antithrombotic, and/or anti-inflammatory effects. There are two types of OO, including extra virgin (EVOO), produced by crushing raw olive fruits, and refined (ROO), obtained through chemical extraction, during which minor components, including phenolic compounds, are mostly lost. Both types of OO have comparable quantities (98-99%) of monounsaturated fatty acids (MUFAs), principally oleic acid. MUFAs are widely credited with OO's cardioprotective effects. While many studies make no distinction between EVOO and ROO, others point to potentially beneficial effects of minor components present in only in EVOO.
This is the first study to report effects of an EVOO and a ROO on CV risk factors in patients with FM. FM is more prevalent in women than men, and only women were included in the study population, recruited from the Association of Fibromyalgia of Jaén (Spain). Inclusion criteria were diagnosis of FM; exclusion criteria, presence of other chronic disease, pregnancy / lactation, intolerance to OO, grade II obesity (body mass index [BMI] ≥ 35 kg/m2), use of medications affecting antioxidant status, and use of certain other medications during the 60 days preceding the study. No participants used alcohol or tobacco (Nicotiana tabacum, Solanaceae). All were sedentary. Thirty women were randomized to two groups (n = 15 each). One group consumed 50 mL/d of a raw organic EVOO; the other, 40 mL/d raw organic ROO. Since the population of Spain uses OO regularly, a two-week washout period with ROO preceded the intervention. StudyOOs (Olifarma S.A.; Granada) were in similar containers and participants were blinded to the OO they were given. Participants were also supplied with ROO for cooking purposes. A 24-hour food recall was completed for three days (two workdays and a weekend day) at the beginning of the study. Average values were used to calculate participants energy (k/cal), macronutrient, protein, and micronutrient intake, and a diet was recommended for each to normalize antioxidant intake. Blood markers and anthropometric measures were assessed before the intervention period (baseline) and after three weeks of OO supplementation. Blood was drawn in morning hours after overnight fasting. To measure compliance, used and unused OO containers were returned at the end of the study.
Baseline and post-intervention blood plasma samples were used to determine thrombosis-related factors including fibrinogen levels, prothrombin time, cephalin time platelet count, platelet distribution width (PDW), mean platelet volume (MPV), red blood cell count (RBC), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and erythrocyte sedimentation rate (ESR). Serum samples were used to measure inflammatory markers including interleukin (IL)-6, IL-10, C-reactive protein (CRP), cortisol, and nitric oxide (NO) levels and lipid profiles including total cholesterol (TC), high-density lipoprotein (HDL)-C, low-density lipoprotein (LDL)-C, triglycerides (TGs), apolipoprotein (apo) A, and apo B. Differences were statistically significant at P < 0.05.
Participants’ mean age was similar in both groups. All completed the trial and returned all used and unused containers. Weight and BMI did not change significantly during the trial. There was a significant decrease from baseline to post study in waist circumference (WC) in the ROO group (P < 0.05), with a medium effect size. There were significant reductions from baseline to post study RBC and ESR (P < 0.05 for each) in the EVOO group, with large effect sizes for both. In the ROO group, there was a significant increase of MPV and significant decreases in PDW, NLR, ESR, and fibrinogen from baseline to post study (P < 0.05 for all), with large effect sizes for these parameters. The PDW had declined significantly (P < 0.05) at the end of the study in the ROO group vs. the EVOO group. Cortisol decreased in the EVOO group but rose with ROO. Large effect sizes were seen for both. There were no significant lipid changes in either group.
In this trial, EVOO or ROO supplementation for three weeks improved CV risk factors in women with FM. While no significant improvements were seen in inflammatory markers or lipids, longer OO trials have reported lower CRP and IL-6 and improved lipids in participants with elevated CVD risks. Results suggest that EVOO's minor components play little part in OO's CV benefits. No significant changes were seen in NO levels in this trial, but in vivo research suggests that pomace OO, a byproduct of ROO production, may have endothelial benefits due to its oleanolic acid. WC was the only anthropometric measure that significantly changed in this study, but longer studies suggest that OO intake can help reduce weight and BMI. Research in larger groups is needed. The authors declare no conflict of interest.