Is Olive Oil Really a "Superfood"? What the Science Says about Olive Oil and Heart Health - Center for Nutrition Studies
In recent years, olive oil has achieved a level of prominence few foods ever have. If you read health magazines or follow nutrition discussions on social media, you’ve probably noticed this upward trend, with. . .
In recent years, olive oil has achieved a level of prominence few foods ever have. If you read health magazines or follow nutrition discussions on social media, you’ve probably noticed this upward trend, with more and more headlines portraying olive oil as an almost miraculous food. Some describe it as a heart protector, others claim it reduces inflammation, and many recommend consuming several tablespoons a day as part of a healthy diet. Before accepting that we’re looking at a true “superfood,” it’s worth asking a few questions that rarely appear in the headlines:Does the scientific evidence support these claims? What do the studies actually show? And what don’t they show?To answer these questions, we must look carefully at the evidence, understand how the key studies were designed, and, above all, avoid conclusions that the research was never intended to answer. When a Food Becomes a HeroOne of the most common mistakes in nutrition research is to try to explain the benefits of an entire dietary pattern by studying only a single food, or even a single nutrient. Dr. T. Colin Campbell has described this way of thinking asreductionism: the tendency to oversimplify extraordinarily complex biological systems and attribute the effects of an entire dietary pattern to single components. [1][2]It’s a way of thinking about and studying nutrition that leads to all kinds of challenges and confusion. We’ve seen reductionism in nutrition time and time again. For years, antioxidants, vitamin C, and omega-3 fatty acids dominated nutrition headlines. Today, we see an almost obsessive focus on protein (though this is not necessarily new). Likewise, olive oil has more recently taken center stage in many conversations about diet and health. The problem with reductionism is that our body does not merely respond to isolated foods. It responds to the overall dietary pattern. The thousands of compounds found in foods interact with one another, producing effects that are difficult—if not impossible—to explain by studying a single ingredient in isolation. [2][3]The Question Too Few AskWhen we read a statement such as “Olive oil protects the heart,” it’s worth stopping to ask a follow-up question: compared to what? Does olive oil protect the heart on its own, or is it only healthier than the foods it might replace within a particular dietary pattern, like butter?This may seem like a subtle distinction, but it is essential to correctly interpreting the scientific evidence. Just because one food is better than another doesn’t mean it’s the best food. Comparing olive oil to butter is not the same as comparing it to a whole food, plant-based (WFPB) diet. Even if it does compare favorably to butter, does that mean it is also beneficial to add olive oil to an already healthy WFPB eating pattern? Not necessarily. When we forget to observe this context, we risk misattributing the benefits of an overall dietary pattern to a single food. And that is exactly what has happened with much of the research on olive oil. What Did the PREDIMED Study Actually Show?If there is one study that is repeatedly cited in support of olive oil’s health benefits, it is the PREDIMED trial (Prevención con Dieta Mediterránea, orPrevention with Mediterranean Diet). Originally published in 2013, the study enrolled more than 7,000 individuals at high cardiovascular risk in Spain and assigned them to one of three groups:A Mediterranean diet supplemented with extra-virgin olive oilA Mediterranean diet supplemented with mixed nutsA control group that was advised to reduce dietary fat intakeThe results showed a lower incidence of major cardiovascular events in both Mediterranean diet groups compared with the control group. Later, after irregularities were identified in the randomization process, the data were reanalyzed and republished in 2018. The main conclusions remained unchanged. [4]From that point forward, PREDIMED became one of the most frequently cited studies supporting the consumption of extra-virgin olive oil and helped establish the idea that olive oil plays a central role in the health benefits of the Mediterranean diet. In the years that followed, several large observational studies and clinical trials comparing the Mediterranean diet with Western or less healthy dietary patterns reinforced that perception. Many healthcare professionals who advocated for plant-based nutrition also began recommending that, if people used oil, extra-virgin olive oil was the best choice. [5–7]However, this brings us back to the earlier question: Compared to what?PREDIMED did not compare extra-virgin olive oil with a WFPB diet. Nor was it a simple single-ingredient comparison of olive oil versus whole olives, or other whole food fat sources, such as nuts, seeds, or avocados. What it compared were entire dietary patterns. The participants assigned to the Mediterranean diet supplemented with either olive oil or mixed nuts, but that was not all they changed. They also increased their intake of vegetables, fruits, legumes, and other hallmark foods of the Mediterranean diet while reducing their consumption of less healthy foods. Therefore, it is not possible to attribute the observed benefits exclusively to olive oil (or to the nuts). The study’s design simply was not intended to answer that question. None of this diminishes the importance of PREDIMED. It remains one of the most influential clinical trials on dietary patterns and cardiovascular risk. But interpreting it correctly requires recognizing both what it demonstrated and what it could not demonstrate. PREDIMED showed that a Mediterranean dietary pattern can reduce cardiovascular riskcompared with the control group. This risk reduction was true of the group that supplemented with mixed nuts as well as the group that supplemented with extra-virgin olive oil, and there was not a statistically significant difference in cardiovascular events between these two experimental groups. Both groups saw a roughly 30 percent decrease in risk compared with the control. What PREDIMED did not show is that olive oil, by itself, was responsible for those benefits. Does Adding Olive Oil Provide Additional Benefits to a WFPB Diet?For many years, this question remained largely unanswered. Most studies compared olive oil with animal fats or butter, or else compared dietary patterns containing olive oil with Western dietary patterns. But in 2024, a clinical trial compared two versions of a WFPB diet: one that included approximately four tablespoons of extra-virgin olive oil per day, and another that included less than one teaspoon daily. [8]Named the Recipe for Heart study, it was a crossover trial, meaning all participants followed both interventions, serving as their own controls. This type of study design reduces variability between individuals and allows for a more precise comparison of the effects of each intervention. As expected, both versions of the WFPB diet improved several cardiometabolic markers compared with the participants’ usual diets. However, one finding stood out: the lower-oil version produced a significantly greater reduction in LDL cholesterol. The researchers also observed that adding larger amounts of extra-virgin olive oil appeared to attenuate part of that LDL reduction. [8]The study was relatively small, lasted only a short period, and primarily evaluated cardiovascular risk factors rather than clinical outcomes, such as heart attacks or strokes. Nevertheless, it provides an important piece of the puzzle. For the first time, a clinical trial directly addressed a question that previous studies had largely overlooked: when the diet is already based on whole, minimally processed plant foods, adding large amounts of olive oil does not appear to provide additional cardiovascular benefit and may lessen some of the LDL cholesterol reduction. Subscribe toour newsletter!Subscribe to our newsletter!Stay up-to-date on the latest from the Center for Nutrition Studies!What about the Polyphenols?At this point, you might be wondering about the often-touted beneficial compounds in extra-virgin olive oil. Are they responsible for the oil’s potential health benefits? And don’t we want them?The answer is yes, but with nuance. Extra-virgin olive oil does contain polyphenols, and numerous studies suggest that these compounds possess antioxidant and anti-inflammatory properties that may support cardiovascular health. [9][10]However, once again, we must avoid falling into the trap of nutritional reductionism. To reiterate what Dr. Campbell explains inWhole, foods function as complex biological systems. When we attribute the benefits of a food to a single component, we risk overlooking the effects of the whole food and the dietary pattern in which it is consumed. [2]Furthermore, polyphenols are by no means unique to olive oil. A WFPB diet provides an extraordinary diversity of polyphenols from fruits, vegetables, legumes, whole grains, nuts, seeds, herbs, spices, tea, cocoa, and countless other plant foods. [11]Importantly, these whole foods also contain other health-promoting compounds. When olive oil is processed from whole olives, virtually all of the fiber and part of the food’s complex matrix are removed. Although olive oil retains some beneficial compounds, including polyphenols, it no longer represents the total health package of the whole food from which it came. [12]The most important question is not whether olive oil contains polyphenols, but whether we need to consume olive oil to obtain the benefits of polyphenols. The evidence does not demonstrate that we do. The presence of one favorable component is not enough to make a food indispensable, especially when it has lost many other beneficial components during processing. How Does a WFPB Diet Lower Cholesterol?The answer likely doesn’t depend on a single food or factor (a reductionist explanation), but rather on the combination of numerous mechanisms working together. One notable characteristic of the WFPB diet is its soluble fiber content. Found in many foods, such as legumes, oats, barley, fruits, and many vegetables, soluble fiber forms a gel in the intestine that binds to bile acids. Bile acids are compounds the liver produces from cholesterol to help digest dietary fat. When soluble fiber binds with bile acids and they are excreted, the liver must synthesize more bile acids. To do so, the liver draws cholesterol from the bloodstream, thereby lowering LDL cholesterol levels. [13]Whole plant foods also provide plant sterols, a wide variety of phytochemicals, and a complex food matrix that influences digestion, nutrient absorption, and metabolism. None of these components acts in isolation; rather, their benefits appear to result from their interaction with one another. By contrast, although extra-virgin olive oil retains some bioactive compounds, it is composed almost entirely of fat and provides approximately 120 calories per tablespoon, with no fiber and a much higher caloric density than the whole olive from which it is derived. [12]Studies have also shown that, beyond their effects on cholesterol, meals high in added fats can temporarily impair endothelial function (the ability of the thin inner lining of blood vessels to regulate blood flow and maintain vascular health). This effect has also been observed after meals containing olive oil, although some studies suggest that the polyphenols in extra-virgin olive oil may lessen this response compared with other sources of dietary fat. [17][18]In contrast, meals centered on whole plant foods that are naturally rich in fiber appear to better preserve endothelial function after eating. [19]These mechanisms help explain why, in numerous clinical trials conducted by researchers such as Dean Ornish, Caldwell Esselstyn, and Neal Barnard, interventions based on a low-fat WFPB diet have produced substantial reductions in LDL cholesterol and, in some cases, even regression of cardiovascular disease. [14–16]The Real Star Was Never the OilWhen the conversation centers on finding the next “miracle ingredient,” we risk losing sight of what truly matters: filling our plates with fruits, vegetables, legumes, whole grains, and other minimally processed plant foods. Health rarely depends on a single food. Rather, it depends on the overall dietary pattern and the synergistic interaction between thousands of compounds in whole foods. When we stop searching for the next “superfood” and instead begin building our meals around whole foods, we move closer to the way human biology actually works. Olive oil may be a better choice than butter or other sources of fat, but that does not mean it is preferable, much less essential, for achieving optimal cardiovascular health. Collectively, we could do a much better job of assessing and reporting on the research involving oil. Despite catching so many headlines, it does not need to be the central character in our health stories. 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