{"product_id":"does-olive-oil-harm-blood-vessels-after-a-meal-a-patients-guide-to-the-2000-mediterranean-diet-study","title":"Does Olive Oil Harm Blood Vessels After a Meal? A Patient's Guide to the 2000 Mediterranean Diet Study","description":"\u003cp\u003eA groundbreaking study published in the Journal of the American College of Cardiology in 2000 investigated how different components of the Mediterranean diet affect blood vessel function after meals. Researchers at the University of Maryland fed 10 healthy volunteers five different high-fat meals and measured how well their arteries dilated. They discovered that olive oil—despite being a cornerstone of the heart-healthy Mediterranean diet—actually temporarily impaired blood vessel function by 31%, while omega-3-rich canola oil and salmon did not. However, adding antioxidant vitamins or vinegar and salad to the olive oil largely prevented this harmful effect, pointing to antioxidants and omega-3 fats as the true protective components of this famous diet.\u003c\/p\u003e\n\n\u003ch1\u003eDoes Olive Oil Harm Blood Vessels After a Meal? A Patient's Guide to the 2000 Mediterranean Diet Study\u003c\/h1\u003e\n\n\u003ch2\u003eTable of Contents\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"#ddn-key-points\"\u003eKey Points\u003c\/a\u003e\u003c\/li\u003e\n\n  \u003cli\u003e\u003ca href=\"#background\"\u003eBackground: Why Study the Mediterranean Diet?\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#methods\"\u003eStudy Methods: How the Research Was Conducted\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#findings\"\u003eKey Findings: Detailed Results With All Numbers\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#discussion\"\u003eDiscussion: What the Results Mean\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#other-studies\"\u003eWhat Other Research Has Shown\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#limitations\"\u003eStudy Limitations: What This Study Couldn't Prove\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#conclusions\"\u003eConclusions and Recommendations for Patients\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"#ddn-faq\"\u003eFrequently Asked Questions\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"#source\"\u003eSource Information\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003c!-- ddn:keypoints:start --\u003e\n\u003ch2 id=\"ddn-key-points\"\u003eKey Points\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eIn 10 healthy volunteers, a meal of extra-virgin olive oil and bread reduced flow-mediated vasodilation by 31% three hours after eating.\u003c\/li\u003e\n\u003cli\u003eCanola oil and salmon meals, rich in omega-3 fatty acids, did not significantly impair blood vessel function in the same 10 volunteers.\u003c\/li\u003e\n\u003cli\u003eAdding vitamins C and E reduced the olive oil-induced impairment by 71%; adding vinegar and salad reduced it by 65%.\u003c\/li\u003e\n\u003cli\u003eAll five test meals raised serum triglycerides by 27% to 45%, and higher triglyceride rises correlated with greater declines in blood vessel function.\u003c\/li\u003e\n\u003cli\u003eThis short-term study of single meals cannot show long-term heart attack or stroke outcomes, and its findings warrant further investigation.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- ddn:keypoints:end --\u003e\n\n\n\u003ch2 id=\"background\"\u003eBackground: Why Study the Mediterranean Diet?\u003c\/h2\u003e\n\n\u003cp\u003eThe Mediterranean diet—consisting largely of olive oil, pasta, fruits, vegetables, fish, and wine—has long been associated with a surprisingly low rate of cardiovascular events (heart attacks and strokes). This observation seemed unexpected because people following this diet have serum cholesterol levels similar to those of people in countries with much higher rates of heart disease.\u003c\/p\u003e\n\n\u003cp\u003eObservational studies have found connections between lower rates of coronary disease and higher intake of fish, fruits, and vegetables. The famous \u003cstrong\u003eLyon Diet Heart Study\u003c\/strong\u003e reported a reduction in cardiovascular events in heart disease patients who were randomly assigned to a Mediterranean diet. But here's the twist: that study substituted \u003cstrong\u003ealpha-linolenic acid (omega-3 fatty acid) enriched canola oil\u003c\/strong\u003e for the traditionally consumed olive oil, which is rich in omega-9 fatty acids.\u003c\/p\u003e\n\n\u003cp\u003eImportantly, this modified Mediterranean diet did not change serum lipoproteins (blood fats), suggesting that the benefit came from some mechanism other than cholesterol reduction. Other prospective diet trials found that heart disease patients advised to eat more fruits and vegetables, eat more fish, or take omega-3 fish oil supplements had fewer cardiovascular events.\u003c\/p\u003e\n\n\u003cp\u003eHigh-saturated-fat diets are potentially atherogenic (artery-clogging) because they raise serum cholesterol, increase blood coagulation (clotting), and impair endothelial function. The endothelium is the thin layer of cells lining blood vessels, and \u003cstrong\u003eendothelial dysfunction is a known risk factor for atherosclerosis\u003c\/strong\u003e (hardening of the arteries).\u003c\/p\u003e\n\n\u003cp\u003eA high–saturated-fat diet impairs endothelial function, possibly because of oxidative stress (damage to cells by free radicals). Intravenously administered fat emulsions also produce endothelial dysfunction. Because the Mediterranean and Lyon Diet Heart Study diets are not associated with low cholesterol levels, the researchers hypothesized that olive, fish, and canola oils have other vasoprotective (blood-vessel-protecting) properties—specifically, that they do not impair endothelial function after meals.\u003c\/p\u003e\n\n\u003ch2 id=\"methods\"\u003eStudy Methods: How the Research Was Conducted\u003c\/h2\u003e\n\n\u003ch3\u003eStudy Participants\u003c\/h3\u003e\n\n\u003cp\u003eThe study included \u003cstrong\u003e10 healthy hospital volunteers (5 men, 5 women) ages 28 to 56 years\u003c\/strong\u003e with serum cholesterol and triglyceride levels below 200 mg\/dl. No subjects had coronary risk factors other than age and gender. All subjects ate unrestricted (ad libitum) diets, and none was taking supplemental vitamins or medications—except one male subject who had been on an HMG-CoA reductase inhibitor (statin) for two years.\u003c\/p\u003e\n\n\u003cp\u003eAll participants purposely refrained from exercise on the study days and fasted for 12 hours overnight before being studied. All gave written informed consent, and the protocol was approved by the Institutional Review Board of the University of Maryland.\u003c\/p\u003e\n\n\u003ch3\u003eThe Five Test Meals\u003c\/h3\u003e\n\n\u003cp\u003eEach subject ate all five meals in varied order, starting between 8:00 and 10:00 AM, with at least a one-week interval between meals. All meals contained \u003cstrong\u003e50 g of fat and 900 kcal\u003c\/strong\u003e. The meals were:\u003c\/p\u003e\n\n\u003col\u003e\n  \u003cli\u003e\n\u003cstrong\u003eExtra-virgin olive oil (50 g)\u003c\/strong\u003e with nonpreservative whole-grain bread (120 g)\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCanola oil (50 g)\u003c\/strong\u003e with nonpreservative whole-grain bread (120 g) — contained approximately 5 g of omega-3 fatty acids\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCanned red salmon (420 g)\u003c\/strong\u003e with crackers (30 g) — contained approximately 6 g of omega-3 fatty acids\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eExtra-virgin olive oil (50 g)\u003c\/strong\u003e, whole-grain bread (120 g), plus \u003cstrong\u003evitamin C (1 g) and vitamin E (d,l, alpha-tocopherol, 800 IU)\u003c\/strong\u003e\n\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eExtra-virgin olive oil (50 g)\u003c\/strong\u003e, whole-grain bread (120 g), plus \u003cstrong\u003ebalsamic vinegar (100 ml) and salad\u003c\/strong\u003e [romaine lettuce (1.5 cup), carrot (1 medium-sized), tomato (1 medium-sized)]\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch3\u003eMeasurements\u003c\/h3\u003e\n\n\u003cp\u003eFasting blood was drawn for total, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol, triglycerides, and glucose. Heart rate, blood pressure, and \u003cstrong\u003ebrachial artery flow-mediated vasodilation (FMD)\u003c\/strong\u003e were assessed before the meal and again 3 hours after completion of the meal.\u003c\/p\u003e\n\n\u003cp\u003eFMD is a noninvasive measure of endothelial function. Using 11.0-MHz linear array ultrasound, the brachial artery (the main artery in the upper arm) was imaged at baseline, then again 1 minute after a 5-minute upper arm blood pressure cuff occlusion. The FMD was calculated as the percent diameter change of the post-occlusion measurement relative to the average of two baseline measurements.\u003c\/p\u003e\n\n\u003cp\u003eThe study had \u003cstrong\u003e80% power to detect a 3% reduction in FMD\u003c\/strong\u003e and \u003cstrong\u003e90% power to detect a 3.6% reduction\u003c\/strong\u003e. Group values were expressed as mean ± standard deviation (SD). Statistical analysis used analysis of variance (ANOVA) for repeated measures, the two-tailed paired t test, Duncan's Multiple Range Test, and the Tukey test. A p value less than 0.05 was considered statistically significant.\u003c\/p\u003e\n\n\u003ch2 id=\"findings\"\u003eKey Findings: Detailed Results With All Numbers\u003c\/h2\u003e\n\n\u003ch3\u003eBlood Tests: Triglycerides Rose After Every Meal\u003c\/h3\u003e\n\n\u003cp\u003eAll five meals significantly raised serum triglycerides (blood fats), with increases ranging from \u003cstrong\u003e27% to 45%\u003c\/strong\u003e (p \u0026lt; 0.05). However, no significant changes were observed in serum total cholesterol, LDL (\"bad\") cholesterol, HDL (\"good\") cholesterol, or glucose levels after any meal.\u003c\/p\u003e\n\n\u003cp\u003eHere are the triglyceride changes for each meal (measured in mg\/dl):\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eOlive oil and bread: increased from 78 ± 41 to 107 ± 74\u003c\/li\u003e\n  \u003cli\u003eCanola oil and bread: increased from 63 ± 28 to 88 ± 49\u003c\/li\u003e\n  \u003cli\u003eSalmon and crackers: increased from 66 ± 47 to 84 ± 58\u003c\/li\u003e\n  \u003cli\u003eOlive oil with vitamins C and E: increased from 71 ± 36 to 99 ± 69\u003c\/li\u003e\n  \u003cli\u003eOlive oil with salad and vinegar: increased from 82 ± 44 to 119 ± 50\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eThe Key Result: Olive Oil Impaired Blood Vessel Function\u003c\/h3\u003e\n\n\u003cp\u003eThe \u003cstrong\u003eolive oil and bread meal reduced flow-mediated vasodilation (FMD) by 31%\u003c\/strong\u003e, from 14.3 ± 4.2% to 9.9 ± 4.5% (p = 0.008). This means that after eating olive oil, the blood vessels' ability to dilate (widen) in response to increased blood flow was significantly reduced.\u003c\/p\u003e\n\n\u003cp\u003eThis change in FMD following the olive oil meal was significantly different from that following the canola oil and salmon meals (by ANOVA, p = 0.02). The olive oil meal reduced FMD statistically more (p \u0026lt; 0.05) than the other four meals by Duncan's Multiple Range Test, and more (p \u0026lt; 0.05) than the other meals—excepting the olive oil, vinegar, and salad meal—by the Tukey test.\u003c\/p\u003e\n\n\u003cp\u003eA \u003cstrong\u003esignificant inverse correlation was observed between postprandial changes in serum triglycerides and FMD\u003c\/strong\u003e (r = -0.47, p \u0026lt; 0.05). In plain language, the more triglycerides rose after a meal, the more blood vessel function declined.\u003c\/p\u003e\n\n\u003cp\u003eThe reduction in FMD following the olive oil and bread meal was associated with a 2% decrease in post-occlusion arterial diameter (p = 0.09) and a 1.8% increase in baseline arterial diameter (p = 0.14).\u003c\/p\u003e\n\n\u003ch3\u003eWhat Happened With the Other Four Meals?\u003c\/h3\u003e\n\n\u003cp\u003e\u003cstrong\u003eNo significant changes in FMD were observed after any of the other four meals.\u003c\/strong\u003e The FMD values before and after each meal were:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eCanola oil and bread: 13.0 ± 3.4% before, 11.6 ± 4.4% after (not significant)\u003c\/li\u003e\n  \u003cli\u003eSalmon and crackers: 13.1 ± 5.2% before, 12.8 ± 5.1% after (not significant)\u003c\/li\u003e\n  \u003cli\u003eOlive oil + vitamins C and E: 13.3 ± 6.8% before, 12.1 ± 5.7% after (not significant)\u003c\/li\u003e\n  \u003cli\u003eOlive oil + salad and vinegar: 13.5 ± 3.5% before, 12.1 ± 3.5% after (not significant)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eNo significant changes were observed in blood pressure or heart rate after any of the five meals.\u003c\/p\u003e\n\n\u003ch3\u003eThe Protective Power of Antioxidants\u003c\/h3\u003e\n\n\u003cp\u003ePerhaps the most striking finding was that \u003cstrong\u003evitamins C and E reduced the olive oil–induced impairment in FMD by 71%\u003c\/strong\u003e—the impairment was largely prevented when these antioxidant vitamins were added to the meal. Similarly, \u003cstrong\u003ebalsamic vinegar and salad reduced the impairment by 65%\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003ch2 id=\"discussion\"\u003eDiscussion: What the Results Mean\u003c\/h2\u003e\n\n\u003cp\u003eContrary to part of the researchers' original hypothesis, this study found that \u003cstrong\u003eomega-9 (oleic acid)-rich olive oil impairs endothelial function after a meal\u003c\/strong\u003e. The change in FMD correlated with the change in serum triglycerides, so the effect probably results from triglyceride-containing lipoproteins (fat-carrying particles in the blood).\u003c\/p\u003e\n\n\u003cp\u003eThe mechanism appears to be \u003cstrong\u003eoxidative stress\u003c\/strong\u003e, because the decrease in FMD was reduced by 71% when antioxidant vitamins C and E were given alongside the meal. This finding supports the idea that the transient impairment in blood vessel function after fatty meals is caused by free radical damage that can be neutralized by antioxidants.\u003c\/p\u003e\n\n\u003ch3\u003eWhy Would Olive Oil Impair Endothelial Function?\u003c\/h3\u003e\n\n\u003cp\u003eOlive oil is highly monounsaturated (72% monounsaturated fat), and it does have beneficial effects on serum lipoproteins. The major unsaturated fatty acids in olive oil are oleic acid (18:1n-9) and linoleic acid (18:2n-6). However, a recent report showed that a high-oleic and linoleic acid (sunflower oil) meal impairs FMD compared with a low-fat meal—supporting the current study's observations.\u003c\/p\u003e\n\n\u003cp\u003eLaboratory studies have shown that albumin-bound oleic and linolenic acids reduce vascular ring endothelium-dependent vasodilation, and remnant particles (partially digested fat particles) obtained from postprandial (after-meal) human blood impair rabbit aorta endothelium-dependent vasodilation in a dose-dependent fashion. Olive oil also has a 17% saturated fat content, and in a clinical study, olive oil activated coagulation factor VII (a blood-clotting protein) to the same extent as butter.\u003c\/p\u003e\n\n\u003cp\u003eThe authors concluded: \u003cstrong\u003e\"Olive oil does not have a clearly beneficial effect on vascular function.\"\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003ch3\u003eA Note on Canola Oil\u003c\/h3\u003e\n\n\u003cp\u003eCanola oil, which contains approximately 5 g of omega-3 fatty acids per 50 g serving, did \u003cstrong\u003enot\u003c\/strong\u003e significantly reduce FMD in this study. The researchers suggested that canola oil may share some of the unique vasoprotective (blood-vessel-protecting) properties of other omega-3-rich oils, such as fish oil.\u003c\/p\u003e\n\n\u003ch2 id=\"other-studies\"\u003eWhat Other Research Has Shown\u003c\/h2\u003e\n\n\u003ch3\u003eHigh-Fat Meals and Endothelial Function\u003c\/h3\u003e\n\n\u003cp\u003eThe research team had previously reported that a high–saturated-fat meal transiently impairs endothelial function, probably as a result of increased circulating levels of free fatty acids and\/or remnant particles. Similar decreases in FMD have been reported with high–saturated-fat meals in other studies. This impairment can be reversed by prior administration of an \u003cstrong\u003eangiotensin-converting enzyme (ACE) inhibitor\u003c\/strong\u003e (a blood pressure medication).\u003c\/p\u003e\n\n\u003cp\u003ePurple grape juice, which is rich in polyphenol antioxidants, improved FMD in one of two reported studies. Free radical production, measured by electron paramagnetic resonance spectroscopy, was found to increase in subjects fed a high-fat meal, supporting the oxidative stress theory.\u003c\/p\u003e\n\n\u003ch3\u003eThe Mediterranean Diet Evidence Base\u003c\/h3\u003e\n\n\u003cp\u003eThe \u003cstrong\u003eSeven Countries Study\u003c\/strong\u003e found rates of coronary heart disease to be much lower on the Greek island of Crete than would be expected for the mean serum cholesterol level. The \u003cstrong\u003eLyon Diet Heart Study\u003c\/strong\u003e reported a reduction in cardiovascular events in heart disease patients given a Mediterranean diet modified by substituting alpha-linolenic acid (omega-3 fatty acid)-enriched canola oil for traditionally consumed olive oil, compared with a prudent French diet.\u003c\/p\u003e\n\n\u003ch3\u003eFish, Fish Oil, and Heart Health\u003c\/h3\u003e\n\n\u003cp\u003eFish consumption is inversely associated with the incidence of cardiovascular events. Fish oils decrease serum very-low-density lipoproteins (VLDL), triglycerides, platelet aggregation (clotting), and inflammation, and they increase membrane stability and endothelial function. The clinical benefit of fish and fish oil has been confirmed in prospective trials:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eThe \u003cstrong\u003eDiet and Reinfarction Trial (DART)\u003c\/strong\u003e found a \u003cstrong\u003e29% reduction in mortality\u003c\/strong\u003e in post–myocardial infarction (heart attack) patients advised to eat more fish.\u003c\/li\u003e\n  \u003cli\u003eThe \u003cstrong\u003eIndian Experiment of Infarct Survival\u003c\/strong\u003e found significant reductions in cardiac death, nonfatal heart attacks, and cardiovascular events in subjects given either omega-3 fatty acid supplementation (2 g\/day) or omega-3 fatty-acid-containing mustard oil.\u003c\/li\u003e\n  \u003cli\u003eThe \u003cstrong\u003eGISSI study\u003c\/strong\u003e (Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto miocardico) reported a \u003cstrong\u003e15% reduction in mortality in 11,324 post–heart attack patients\u003c\/strong\u003e given omega-3 fatty acid supplementation (1 g\/day).\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eFruits and Vegetables\u003c\/h3\u003e\n\n\u003cp\u003eThe consumption of fruits and vegetables has been associated with lower incidences of cardiovascular events. Postulated mechanisms include increased antioxidant intake, increased fiber intake (with resulting decreased serum LDL), increased potassium intake, and decreased blood pressure. An Indian study found that adding fruits, vegetables, nuts, and grain products to a fat-reduced diet lowered cardiovascular events, including mortality, in post–heart attack patients.\u003c\/p\u003e\n\n\u003ch2 id=\"limitations\"\u003eStudy Limitations: What This Study Couldn't Prove\u003c\/h2\u003e\n\n\u003cp\u003eThe authors were careful to acknowledge several important limitations:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003eAlthough considerable data support an atherogenic role for endothelial dysfunction, the assumption that endothelial function predicts progression of atherosclerosis and\/or cardiovascular event risk is supported only by preliminary data.\u003c\/li\u003e\n  \u003cli\u003eThe study documented postprandial changes after a large morning meal. Whether similar effects would be observed at other times of day is unknown, especially in view of circadian variations in hepatic and digestive metabolism.\u003c\/li\u003e\n  \u003cli\u003eThe study involved a small subject group (10 people), although significant changes were still observed after the olive oil and bread meal. Several other studies employing the brachial artery FMD technique have been of similar size.\u003c\/li\u003e\n  \u003cli\u003eThe researchers did not measure responses to nitroglycerin (a medication that directly relaxes blood vessels), because they and other investigators have reported that these are unaffected by a fatty meal. This means they could not fully distinguish between endothelium-dependent and endothelium-independent effects.\u003c\/li\u003e\n  \u003cli\u003eThe study does not establish that the decrease in FMD is entirely endothelium-dependent, because the majority—but not all—of the decline in FMD was due to a decrease in post-occlusion arterial diameter. The data do not exclude a direct vasodilator effect (endothelium-independent) of the olive oil by itself, as there was a trend toward increased baseline diameter. Two prior studies observed a direct vasodilator effect of a high-fat meal, and one study observed a direct vasodilator effect after intravenous lipid emulsion—but most other prior studies have not.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"conclusions\"\u003eConclusions and Recommendations for Patients\u003c\/h2\u003e\n\n\u003cp\u003eThe researchers concluded that, in terms of their effects on postprandial (after-meal) endothelial function, \u003cstrong\u003ethe beneficial components of the Mediterranean and Lyon Diet Heart Study diets appear to be the antioxidant-rich foods—vegetables, fruits, and their derivatives such as vinegar, and omega-3-rich fish and canola oils—not olive oil.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThis conclusion has several practical implications for people interested in heart-healthy eating:\u003c\/p\u003e\n\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAntioxidants matter.\u003c\/strong\u003e Adding vitamin C and vitamin E, or simply eating a salad with vinegar alongside a fatty meal, substantially reduced the temporary decline in blood vessel function caused by olive oil (by 71% and 65%, respectively).\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOmega-3 fats are protective.\u003c\/strong\u003e Canola oil and salmon, both rich in omega-3 fatty acids, did not impair endothelial function after a meal, unlike olive oil.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eOlive oil is not a free pass.\u003c\/strong\u003e While olive oil has beneficial effects on cholesterol levels, this study suggests it may temporarily impair blood vessel function after consumption—a finding that warrants further investigation.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eFruits and vegetables provide protection.\u003c\/strong\u003e Dietary intake of fruits, vegetables, and their products appears to provide some protection against the direct impairment in endothelial function produced by high-fat foods, including olive oil.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eIt's important to remember that this was a short-term study measuring immediate effects after a single meal—not a long-term trial of heart attack or stroke outcomes. The body of evidence supporting the overall health benefits of a Mediterranean-style diet remains strong. However, this study provides valuable insight into \u003cem\u003ewhich components\u003c\/em\u003e of the Mediterranean diet confer the most vascular protection, and suggests that emphasizing omega-3-rich fish and canola oil, along with antioxidant-rich vegetables and fruits, may be more beneficial than relying primarily on olive oil alone.\u003c\/p\u003e\n\n\u003c!-- ddn:faq:start --\u003e\n\u003ch2 id=\"ddn-faq\"\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003ch3\u003eWhat did this study find about olive oil and blood vessel function after a meal?\u003c\/h3\u003e\n\u003cp\u003eIn 10 healthy volunteers, a meal of extra-virgin olive oil and whole-grain bread reduced flow-mediated vasodilation, a measure of blood vessel function, by 31% three hours after eating. This temporary impairment was significantly different from the effects of canola oil and salmon meals, which did not impair blood vessel function.\u003c\/p\u003e\n\u003ch3\u003eWhat are flow-mediated vasodilation (FMD) and endothelial function?\u003c\/h3\u003e\n\u003cp\u003eFMD is a noninvasive ultrasound measure of how well the brachial artery in the upper arm widens in response to increased blood flow. It reflects endothelial function, the health of the thin layer of cells lining blood vessels. Endothelial dysfunction is a known risk factor for atherosclerosis, or hardening of the arteries.\u003c\/p\u003e\n\u003ch3\u003eDid adding vitamins or salad prevent the olive oil effect?\u003c\/h3\u003e\n\u003cp\u003eYes. Adding vitamins C and E to the olive oil meal reduced the impairment in FMD by 71%, and adding balsamic vinegar and salad reduced it by 65%. This suggests that antioxidants in these additions largely prevented the temporary blood vessel impairment caused by the olive oil meal.\u003c\/p\u003e\n\u003ch3\u003eWhat were the limitations of this study?\u003c\/h3\u003e\n\u003cp\u003eThe study included only 10 healthy volunteers and measured effects after a single large morning meal, so it could not show long-term heart attack or stroke outcomes. It also could not fully distinguish endothelium-dependent from endothelium-independent effects. The authors noted that the link between endothelial function and cardiovascular events is supported only by preliminary data.\u003c\/p\u003e\n\u003ch3\u003eWhat do the triglyceride changes mean for patients?\u003c\/h3\u003e\n\u003cp\u003eAll five meals raised serum triglycerides by 27% to 45%, but only the olive oil meal impaired FMD. The study found an inverse correlation between triglyceride changes and FMD, meaning the more triglycerides rose after a meal, the more blood vessel function declined. This suggests the effect may involve triglyceride-containing lipoproteins.\u003c\/p\u003e\n\u003ch3\u003eShould I stop eating olive oil based on this study?\u003c\/h3\u003e\n\u003cp\u003eThis was a short-term study of immediate effects after one meal, not a long-term trial of heart attack or stroke outcomes. The body of evidence supporting the overall health benefits of a Mediterranean-style diet remains strong. The findings suggest emphasizing omega-3-rich fish and canola oil, along with antioxidant-rich vegetables and fruits, may be more beneficial than relying primarily on olive oil alone.\u003c\/p\u003e\n\u003ch3\u003eShould I get a second opinion before changing my heart-healthy diet based on the 2000 olive oil study?\u003c\/h3\u003e\n\u003cp\u003eA second opinion is reasonable before making dietary decisions based on a single-meal study of 10 healthy volunteers. That research measured brachial artery flow-mediated vasodilation three hours after each meal; olive oil and bread reduced it by 31%, while canola oil and salmon did not, and adding vitamins C and E or salad with vinegar reduced the impairment by 71% and 65%. It did not measure heart attacks or strokes over time. A clinician can help interpret these short-term findings alongside your own risk factors. Diagnostic Detectives Network provides independent expert second opinions.\u003c\/p\u003e\n\u003c!-- ddn:faq:end --\u003e\n\n\u003ch2 id=\"source\"\u003eSource Information\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eOriginal Article Title:\u003c\/strong\u003e vogel olive oil study 2000\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAuthors:\u003c\/strong\u003e Robert A. Vogel, MD, FACC; Mary C. Corretti, MD, FACC; Gary D. Plotnick, MD, FACC (Division of Cardiology, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland)\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eJournal:\u003c\/strong\u003e Journal of the American College of Cardiology, Vol. 36, No. 5, 2000, pages 1455–1460. © 2000 by the American College of Cardiology. Published by Elsevier Science Inc.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c\/strong\u003e Supported by funds from the Center for Vascular Biology and Hypertension, University of Maryland School of Medicine, Baltimore, Maryland.\u003c\/p\u003e\n\n\u003cp\u003eThis patient-friendly article is based on peer-reviewed research originally published in a medical journal. It is intended for educational purposes and should not replace personalized medical advice from a healthcare professional.\u003c\/p\u003e","brand":"DiagnosticDetectives.Com","offers":[{"title":"Default Title","offer_id":47709983539356,"sku":null,"price":0.0,"currency_code":"USD","in_stock":true}],"url":"https:\/\/diagnosticdetectives.com\/es\/products\/does-olive-oil-harm-blood-vessels-after-a-meal-a-patients-guide-to-the-2000-mediterranean-diet-study","provider":"DiagnosticDetectives.Com","version":"1.0","type":"link"}