Debunking the Anti-Fat Agenda

 

(Photo by Francesca Mueller)


Olive oil is a supremely healthy food. Olive oil is 98% fat. Many people find these two statements mutually exclusive. Still under the spell of the anti-fat propaganda that filled our food airwaves and dominated the nutritional discussion in the 1980s and 90s, they wonder, “If olive oil is mostly fat, how can it be healthy?” I’ve considered this problem briefly – the fact is, not all fats are created equal, and extra virgin olive oil is much more than fat alone – but it’s time to debunk this widely popular fat fetish in detail.

Today’s guest writer, Hob Gadling, has spent many years immersed in the scientific literature on the health benefits of olive oil. In this guest column, Hob takes on one of the more insidious attacks on olive oil’s healthfulness. Insidious, because it bears a patina of scientific method and academic credibility, beneath which lie glaring errors of logic and science, and an extreme anti-fat agenda that’s often aimed at selling the Pritikin Diet and similar dietary regimens.  Reading this article, you'll also learn a lot about what makes a solid scientific argument – and the games some people play when their hard evidence is slender.

 

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Bewildered by the barrage of claims and counterclaims about a healthy diet? You’re not alone. The diet wars and the product labels leave many people’s heads spinning, and it often seems like even the experts can’t agree — that is, if you can figure out who the real experts are. So it’s no surprise that many people have had their confidence in the healthfulness of one of the world’s few true health foods undermined by an oft-recycled article that claims that olive oil is bad for you.

Since its original appearance on the internet in 2007, the article has been reprinted with only minor changes, turned into YouTube videos, and copy-pasted into the personal blogs and Facebook pages of dozens of ultra-low-fat diet proponents under headlines like “Is olive oil good for you and your heart?,” “Dispelling the Myths about Olive Oil,” and most famously (and ironically, for readers of this website) “The Truth About Olive Oil.” Its alarming thesis is introduced early on in the piece:

monounsaturated fats like olive oil may be better than foods full of saturated and trans- fats, but just because something is “better” does not mean it is good for you. “Better” cigarettes … still promote lung cancer. “Better” monounsaturated fats like olive oil may still lead to diseased arteries.

It then goes on to summarize a range of scientific-sounding evidence to argue not only that the health benefits of olive oil are hype, but that olive oil is positively bad for you, albeit not as unhealthy as bacon fat or partially-hydrogenated vegetable oil — the “better cigarettes” of the nutrition world. Olive oil? Cigarettes? What are we to make of this?

 

The Elephant Evacuated from the Room

Let’s start with the kind of evidence that the article does not present in its attack. Yes, the article discusses some studies carried out on laboratory animals. And yes, it also includes some studies involving humans, albeit of very particular and limited sorts (and as we’ll see, not always accurately-presented). But as most of us know, the gold standard of scientific evidence — the thing that gives us the strongest proof that something is true or false in the world of health — is the randomized clinical trial, or RCT.

In an RCT, scientists take a large group of people and assign half of them to receive an experimental treatment that the researchers think will benefit their health, such as a new drug. Meanwhile, the rest of the people in the study (the “control group”) receive an alternative intervention that the scientists think will not be effective (such as a sugar pill) or against which they want to test the new intervention (such as an older, established drug). In a true RCT, the scientists take steps to make sure that even though individual people are assigned to the treatment or the control by random processes, the two groups contain similar numbers of people with different personal characteristics, such average age, mix of men and women, number of overweight and obese people, exercise habits, and so on. Then the two groups continue to receive the therapy or the stand-in treatment for several years, to see how it will affect their health (rather than looking back after the fact and trying to piece together why some people developed heart disease and others remained healthy). The RCT is thus the strongest possible kind of evidence to bring to bear on the question of how a given intervention — a drug, a diet, an exercise regimen — really affects a person’s health, with all else being accounted for.

Such studies are the norm when testing drugs: regulators like the Food and Drug Administration require them before a drug is allowed onto the market, and pharmaceutical companies are willing to shell out the money to hire doctors and follow up with patients for years because a successful RCT is the pathway to spectacular profits.

By contrast, it’s very rare to have true RCTs for food, because you don’t need the government’s permission to sell apples, you can’t get a patent on them, so there’s no incentive for apple farmers to go to the expense of paying for a trial of “an apple a day.” But unlike apples (or green tea, or salad greens, or broccoli, or any of the other undoubtedly healthy foods out there), the health benefits of extra-virgin olive oil (EVOO) have been proven in this most rigorous way.

PREDIMED was a randomized controlled trial whose design was so sound — and whose results were judged so important — as to merit publication in the New England Journal of Medicine, one of the top three medical journals in the world.[1] The PREDIMED physicians recruited 7447 Spanish men and women who did not have actual cardiovascular disease, but who were at high risk of heart attack or stroke because of things like overweight and obesity, high blood pressure, high cholesterol, and diabetes. In the balanced-but-random way of the best clinical trials, subjects allocated to groups that would be counseled to follow one of three diets.

All three of the PREDIMED diets were basically healthy, emphasizing fruits and vegetables and lean meats and fish, while minimizing pastries and bakery products, red and processed meats, major sources of saturated and trans-fats like cream, butter, margarine, and pâté, and so on. The key differences between the diets were around fat. The control diet was designed to be the kind of healthy but low-fat diet that the USDA and the American Heart Association used to recommend in the 1980s: subjects were counseled to avoid cooking oils, pull the skin off of chicken, skim the fat off of soups, stop basing their cooking on sofrito (a sauce of vegetables braised in olive oil, used in much of Spanish cuisine), and so on. The other two were variants on the Mediterranean diet, and with a special emphasis on incorporating healthy fat sources. The researchers provided the volunteers with free supplies one of two healthy fat sources —either an ounce of mixed unsalted nuts daily, or a generous supply of extra-virgin olive oil — and lessons on how to use more of them in their diets.

As often happens, the PREDIMED volunteers had a hard time changing their dietary habits very much: in particular, the total fat intake of people assigned to a low-fat diet stayed about the same. Still, people in all three arms of the trial improved their diets: whether assigned to low-fat advice, or to Mediterranean diet with nuts or with extra-virgin olive oil, all three groups improved their scores on a standard “Mediterranean diet” assessment, and cut back on saturated fat intake by 5-10%, even though these Spanish volunteers were already consuming significantly less saturated fat than typical Americans, Brits, or Australians when the study began. Additionally, people in the low-fat diet group cut back significantly on red and processed meat. But the biggest differences were in the two groups assigned to Mediterranean diets. The EVOO group increased their extra-virgin olive oil intake to about four tablespoons a day, while cutting their intake of refined olive and seed oils to almost zero. Meanwhile the group assigned to a Mediterranean diet with nuts consumed a bit less than an extra ounce of them a day. Both Mediterranean diet groups also became somewhat more regular consumers of red wine.

The question was: compared to a similarly-healthy but low-fat diet, would enriching the diet with these healthy fat sources cut these high-risk subjects’ rates of heart disease, stroke, or death from cardiovascular causes?

 

Stacking the Deck Against Olive Oil

The PREDIMED trial actually didn’t give EVOO its best chance to show its protective powers, because the patients in the study were all given drug therapy to bring their cardiovascular risk factors under control. This meant that (for instance) volunteers who had high levels of LDL (“bad”) cholesterol in their blood would get statins drugs to lower it — good medical care, but making extra-virgin olive oil’s ability to lower LDL a bit redundant. The same goes to a lesser extent for high blood sugar after eating a meal and high blood pressure: there’s evidence that EVOO can help to lower these risk factors, but because people with high levels of these risk factors got other medical treatment for them, EVOO’s comparative advantage was not given its full opportunity to shine.

And the study authors didn’t put the strongest competitor into the ring, either. There is now a great deal of evidence that beneficial bioactive phenolic compounds present in extra-virgin olive oil mediate many of its benefits, with more powerful effects on things like blood pressure,[2] oxidized LDL cholesterol (the “baddest of the bad” fraction of LDL, which is most likely to form plaques in your arteries),[2][3][4][5][6][7][8][9] inflammation,[10] and factors regulating blood clotting.[11] The oil used in the study had a respectable level of phenolic compounds (not less than 300 milligrams of phenolics per kilogram of oil, averaging 326 mg/kg)[12] and certainly more what is typically found in American supermarket olive oil, but was still significantly short of the 500 mg/kg or more that fresh, premium EVOO can contain when modern production methods are brought to bear.

 

With One Gleaming Hand Tied Behind its Back

So it was all the more remarkable that the trial ethicists decided to end the trial early — because the results were clear. As compared with people eating the basically healthy diet, people whose diets were enriched in EVOO or nuts suffered close to 30% fewer heart attacks, strokes, and deaths from cardiovascular disease.1 Additionally, although the trend didn’t reach the standard statistical threshold for assurance, there was a pretty clear-looking trend for people consuming EVOO to die less often from any cause.

Now, that’s a pretty clear result. And if someone wants to convince you to disregard a randomized, controlled clinical trial involving nearly 7,500 high-risk Spanish citizens consuming extra-virgin olive oil for five years, they’d better have some pretty good countervailing evidence up their sleeves. Instead, the low-fat diet advocates argue from studies in chimps, human studies run over the course of a few hours, some distortions of the evidence from human epidemiology, and what we might call fuzzy math. Let’s dig into it.

 

Marginal[izing the] Benefits

At one point, the article seems to be talking about something like a clinical trial showing that olive oil isn’t all that beneficial. It says, “data from the Nurses Health Study, an on–going study from Harvard Medical School analyzing the habits and health of nearly 90,000 female nurses, found that those who consumed olive oil were only marginally healthier than those eating a typical high–in–saturated–fat American diet.”

Now, the Nurses’ Health Study is a very important source of scientific information on diet and health that has been going on for decades, so its conclusions can’t be easily dismissed. But unlike PREDIMED, the Nurses’ Health Study is not a controlled trial, where volunteers are assigned in a structured, random-but-balanced way to follow different therapies (whether it’s a drug or a diet) to test the effect of changing just that one thing in people who are otherwise similar. Instead, it’s what’s called an observational study.

In such studies, volunteers go about their lives in whatever way they see fit, following their own diet and lifestyle choices without guidance from the study investigators; what makes it a study and not just life is that volunteers agree to fill out questionnaires every few years that tell the researchers about their lifestyles and their health: what they’re eating, how much exercise they’re getting, health problems they’re experiencing, and so on. In some such studies, volunteers also consent to letting the investigators see their medical records, or to collect blood samples or similar data. Then, the researchers leading the study follow up with the volunteers over the years to see how their health turns out, and use sophisticated statistical methods to try and tease out associations between health outcomes and parts of their previous self-directed lives.

This obviously makes determining cause and effect between things that are associated with one another very difficult. If people who chose to consume more coffee during the course of the study the study wind up getting Parkinson’s disease less often, is it because something in coffee is protective against the disease? Or is it because people who are genetically vulnerable to Parkinson’s don’t handle caffeine well, and thus avoid coffee? Or something else?

The best way to resolve such questions is to randomly assign one group to drink lots of java, and another group to abstain. That’s exactly why RCTs like PREDIMED are necessary.

Observational studies have their place. In fact, as things stand, they’re the best sources of information we have on most questions of lifestyle’s effects on health, exactly because clinical trials of foods and exercise plans are so hard to organize. But let’s be clear: no conclusion coming out of even the best observational study can be as reliable as the results of a 7500-subject RCT.

 

If the Evidence is Against You, Make Some Up

But wait: maybe this observational-vs-RCT ranking doesn’t even matter. Because the claim that the Nurses’ Health Study found only marginal benefits from olive oil consumption is hogwash!

When I first read the “Truth About Olive Oil” piece, I found this claim suspicious. In part, it was because I have paid a lot of attention to this study over the years, and have also paid a lot of attention to olive oil research, and would be surprised if I had missed a key finding like the one that was being claimed. Moreover, for most of the other studies that the article claims to review, a citation back to the original scientific report on which it’s supposed to be based is given — but in this case, no such reference is provided.

The reason turns out to be that there is no such finding in the Nurses’ Health Study. In fact, there is exactly zero data on the subject! I dug around in the medical literature to confirm this, and just to be sure I emailed Dr. Walter Willett, the respected epidemiologist at the Harvard School of Public Health who has been running a section of it for almost a quarter of a century. He confirmed what I had suspected: the Nurses’ Health Study has never reported anything about olive oil and health in the entire four decades of its existence.[13]

If that sounds surprising, the Nurses’ Health Study scientists did have a good reason not to look into this question. Americans in general — and these nurses in particular — have historically consumed so little olive oil that it is unlikely that the tiny amounts present in their diets would have exerted any significant effect on their health. When the Nurses’ Health Study was launched in the 1970s and 80s, vanishingly few Americans were consuming the olive oil-rich diets of the Greeks of Crete, whose low incidence of heart disease sparked the interest of scientists in the Mediterranean diet in the first place, back in the middle of the last century.

In fact, the main sources of monounsaturated fats in the American (and Australian, and Northern European) diet were then (and are now) not EVOO, but dairy, meat, and partially-hydrogenated vegetable oils, which drag down the benefits of monounsaturated fats by mixing them inseparably with unhealthy saturated and trans-fats.[14] And as readers of Extra Virginity will know, even people who think they are using EVOO (and report doing so to study scientists if asked) are often actually consuming doctored seed oils, low-grade olive oil mislabeled “extra-virgin,” and formerly extra-virgin olive oil that has been left sitting next to the stove in a clear glass bottle, turning even the best of oils into half-rancid swill that no longer deserves the “extra-virgin” designation. So looking to the nurse volunteers of this study for a sign of the potential health benefits of extra-virgin olive oil just doesn’t make sense.

But of course, other observational studies have looked credibly into this question. So what do the observational studies really show? When you look at studies actually performed in Mediterranean countries like Spain, Italy, and Greece — countries where a significant number people consume enough olive oil to mean something (i.e., doses greater than two tablespoons a day) — high olive oil consumption is consistently associated with potent protection against cardiovascular disease[15][16] and death from any cause.[17][18][19][20]

And again: a randomized, controlled trial of nearly 7,500 Spanish men and women — one third of them consuming authentic EVOO supplied directly to them by study scientists — has just proven the same point beyond reasonable doubt.

 

False Phenolic Fracas

A couple of times in the article, the author notes (rightly) that a lot of the benefits from extra-virgin olive oil come from the phenolic compounds — a family of valuable bioactive molecules, with antioxidant and many other properties. He even rightly notes that these bioactive compounds are stripped away in the refining process used to make “light,” “pure,” and pomace olive oils. Since you can also find phenolic compounds in leaf lettuce, he argues, there’s no need to reach for a relatively high-calorie food like olive oil to get them.

There are a few problems with this plausible-sounding argument. For one thing, it assumes that a phenolic compound is a phenolic compound is a phenolic compound, and it therefore doesn’t matter whether it comes from olive oil, lettuce, or some other food. But in fact, food phenolics are a wide-ranging and diverse group of molecules, produced by different plants to serve different purposes in their life cycles, and that exert different effects in our bodies when we consume them. Green tea has its epigallocatechin gallate; blueberries have their anthocyanidins; coffee has caffeic acid; and so on.

So yes, there are phenolic compounds in leaf lettuce — but not the ones that dominate in extra-virgin olive oil! In fact, the main group of phenolic compounds in olive oil (the secoiridoids) are found almost nowhere else in the food supply than in olives and olive oil — and even olives don’t deliver quite the same mix as the oil, as the crushing and mixing used to separate the Liquid Gold from the fruit releases enzymes that transform the parent compounds into novel organic creations. All the lettuce in the world is not going to deliver any oleocanthal, hydroxytyrosol, oleuropein, or any other secoiridoid — until you drizzle on the EVOO. (And the reverse is not true, by the way: when you consume extra-virgin olive oil, you do get small amounts of the luteolin, quercetin, and hydroxycinnamic acids you’ll find in lettuce).

Another problem with this argument is that it ignores the fact that part of the benefit of having those phenolics in the olive oil is the effect they have on the olive oil itself. Olive oil is a fresh fruit juice, and like any farm-fresh product its quality degrades over time. While most seed oils are kept from going rancid with food additives, the antioxidant power of the phenolic compounds present in extra-virgin olive oil synergize with the vitamin E to keep it fresher for longer than other oils and fats, with no added antioxidants needed. By the time a refined oil reaches your lettuce plate, it’s already too late for it to benefit in this way from the phenolics that are literally squeezed into extra-virgin olive oil when the olive fruit hits the crusher.

Yet another hole in the “lettuce libel:” your body can only benefit from any food phenolic if it actually absorbs it. But even if you could find an alternative source of the phenolics in extra-virgin olive oil, one study found that you wouldn’t absorb it as well as you can in olive oil itself. In that study, scientists fed a group of study volunteers equivalent amounts of hydroxytyrosol (a food phenolic found almost nowhere else but in olives or olive oil) in each of three different food sources: in its native form as part of extra-virgin olive oil; -in refined olive oil that had its original phenolcs stripped out and was then fortified with added hydroxytyrosol (HT); or in HT-fortified yogurt. The scientists then looked to see how well the subjects absorbed the HT by seeing how much of it they excreted in their urine over the next few hours.[21]

The first thing that the researchers noticed was that HT seemed to be much better-absorbed from “native” EVOO (44.2% of the HT originally present in the oil) than as an additive to refined olive oil (23% of HT administered). Interpreting that finding is complicated by the fact that in addition to the pure HT in the extra-virgin olive oil, EVOO also contains complex molecules that incorporate HT as part of their structure. When you consume these more complex HT-containing molecules, your body breaks them down and releases much of the HT in the stomach, so some of the “extra” HT the scientists saw when subjects consumed HT-rich EVOO would have come from this “hidden” HT, rather than from an intrinsically-superior bioavailability of HT itself.

So this study can’t tell us whether HT is better-absorbed molecule-for-molecule from EVOO than from HT-fortified refined oil. But even in comparing the two HT-fortified foods, where the only HT came from what the scientists added, you could see that HT was much better-absorbed from fortified olive oil (23% of HT administered) than from fortified yogurt (5.8% of HT administered).[22] Thus, the food matrix matters.

And it’s not just something about the specific bioactive compounds that are present in in extra-virgin olive oil. Numerous studies show that many health-promoting food compounds are better absorbed — and in some cases much better-absorbed — when taken with fat. This includes carotenoids, the pigmented compounds that give many vegetables their green, orange, and red hues. And ironically, carotenoids are one of the main nutritional claims to fame of lettuce — the very food that the article’s writer touts for its content of bioactive molecules.[22]

In fact, when compared with other sources of fat, some evidence suggests that olive oil may be especially effective at helping your body absorb some of the specific health-promoting compounds present in green, leafy vegetables, such as lutein (the deep green-colored compound that appears to protect the eyes against late-life blindness from macular degeneration).[23] So the lettuce-versus-olive-oil dichotomy that the author draws is a particularly messy nutritional divorce.

This is even more clearly true if you’re going to liven up your lettuce salad with some diced tomatoes: your absorption of the red pigment lycopene — the carotenoid recognized for its potential to prevent prostate cancer and cardiovascular disease — depends even more substantially on concomitant fat intake than other carotenoids.[24][25][26][27] More fat seems to lead to more absorption of lycopene, with a dose of over one-and-a-half tablespoons of oil being more effective than a teaspoon or less[24][27] — and as with lutein, the kind of fat matters too. An oil rich in the monounsaturated fats that dominate olive oil was found to be more effective at enhancing lycopene absorption from salads than polyunsaturated-fat-rich soybean oil or saturated-fat-rich butter.[27]

And again ironically to the author’s premise, high-phenolic extra-virgin olive oil has a special role to play here. In one study, scientists tested the level and bioavailability of lycopene in pasta sauces made with diced tomatoes cooked in one of four different fat sources: high- or low-phenolic EVOO, high-oleic safflower oil (made from a variety that is high in the same monounsaturated fats as olive oil itself), or regular safflower oil (with a fatty acid profile closer to that of corn oil). Subjects consumed the sauce as part of two sequential pasta meals, and had their blood drawn after each to see how much lycopene they had absorbed. The result: people’s serum lycopene went up more when consuming pasta sauce made with high-phenolic olive oil than did any of the other sauces, especially after the first meal.[28]

Why would this be? A look at the tomato pasta sauces themselves yields a clue. The pasta sauce cooked in high-phenolic olive oil had double the concentration of lycopene present in the sauce cooked with either low-phenolic olive oil or high-oleic safflower oil — and triple the amount of the pasta sauce cooked in more conventional safflower oil![28] Where would this “extra” lycopene come from? The scientists themselves admit they don’t know: “Further investigations are required to understand the mechanisms responsible for the increase in lycopene in the tomato sauce cooked with high phenolic olive oil.”[28] It wasn’t because there was more lycopene in the diced tomatoes used to make the high-oleic EVOO sauce (they all came from the same batch), or because there was lycopene in the olive oil (there wasn’t). So what could it be?

One clue lies in the fact that cooking tomatoes always increases the available level of lycopene in the cooked food, both by helping to release it from its tight attachment to the cell walls,[29][30] and by “flipping” its molecular “handedness” (isomerization, to use the technical term) into a form that is easier to absorb.[30] But cooking simultaneously degrades some of that lycopene,[31][32] and it’s hard to determine just how much that happens, because the two phenomena (increased release and increased degradation) are happening at the same time.

One way to minimize the loss of lycopene is to control your cooking method: shorter cooking times, and temperatures at or below the boiling point, appear to minimize lycopene loss while still allowing lycopene release.[32][33][34] But another may be to add in antioxidants, to protect lycopene from being degraded by oxidative chemistry. This is where the advantage of cooking with a high-phenolic olive oil may have come in. Perhaps its antioxidant phenolic compounds protected the lycopene from being destroyed in the cooking process.

Whatever the mechanism, the result was that cooking with high-phenolic olive oil left more lycopene in the pasta sauce — and more lycopene protecting the volunteers. The attempt to play the phenolics in extra-virgin olive oil against the phenolics in salad vegetables is a false dilemma. These are two great tastes — and two great contributors to good health — that go best together.

 

Creative [Fat] Accounting

Toward the end, the article makes a claim that would put Enron’s accountants to shame: “the American Heart Association recently lowered the recommended intake of saturated fat to no more than 7% of total calories eaten each day. Olive oil is 14% saturated fat. … So if you’re using a lot of olive oil on your food, it’d be hard to have a diet that’s less than 14% saturated fat, which means your arteries are being subjected to double the sat–fat–limit that the AHA recommends.” Well, it might be hard if olive oil made up over half of your diet, but otherwise the numbers don’t work.

Let’s look at what the AHA guidance entails in terms of actual, hard numbers instead of percentages. To keep to the American Heart Association’s guideline, the average American man should keep his saturated fat below 18 grams a day, and the average woman to under 15 grams. Americans are eating less saturated fat today than we did at the peak of the epidemic of cardiovascular disease in the 1960s, but there’s till plenty of room for improvement: the average American takes in about half again as much as we should. But where is all that saturated fat coming from? Not from olive oil! In the United States, the top four contributors to saturated fat intake are cheese, pizza, and various desserts; the top ten also includes processed meats and burgers, and butter and full-fat milk are not far behind.

An ounce of cheddar, Swiss, or Brie contains about 5-6 grams of saturated fat and 25-30 milligrams of cholesterol, so you can see how quickly it adds up. Depending on the amount of cheese and the meat toppings, a typical two-slice serving of pizza can contain anywhere from 4 to 15 grams of saturated fat, and can go as high as 32 grams for the individual-sized California Pizza Kitchen Tostada Pizza with Steak. And it’s no longer just pizza that’s packed with saturated fat from cheap cheese. As New York Times investigative reporter Michael Moss reviews in his eye-opening Salt, Sugar, and Fat, dairy producers began flooding the market with a glut of commodity cheese in the 1980s, as a byproduct of their increasing difficulty in disposing of surplus milk fat. The result: the restaurant and processed food industries seized on the low prices, and have been cramming more and more cheese into their offerings ever since.

So where does olive oil fit into your saturated fat budget? Trivially! A whole tablespoon of EVOO has 1.2 grams of saturated fat and no cholesterol. In the huge Spanish study we reviewed earlier, the average person in the EVOO group brought their total EVOO intake up to about four tablespoons of olive oil a day. That’s a level typical of the Cretan villagers whose remarkable resistance to cardiovascular disease gave rise to the whole notion of the “Mediterranean diet;” it’s also significantly more than the minimum two tablespoon dose that the FDA requires for producers to make a health claim for olive oil, and is consistent with the European Food Safety Authority’s guidance. They also upped their nut intake by about half an ounce. But even that generous daily dose of olive oil has less saturated fat than a single ounce of cheese. And even after adding all the extra olive oil to their diets, the daily intake of saturated fat of people in the EVOO arm of the trial went down, not up — and their absolute intake wound up about a third lower than the average American’s!

Notice, by the way, that the results of PREDIMED completely undercut the article’s notion that olive oil is merely the “lesser evil” of dietary fats: better (it argues) than butter or bacon fat, but still unhealthy. In PREDIMED, all three groups in the study brought their saturated fat intakes down to a little over 9% of energy intake — a level higher than the AHA’s limit, but less than it was before the trial began, and also less than the average American’s 11% of energy. And yet even though their saturated fat intake was no lower than in the group consuming the control diet, the high-EVOO diet reduced their risk of heart attacks, cardiovascular death, and maybe even death from any cause even further, as compared with controls.

The bottom line: bring down your intake of unhealthy fat, yes. But do it the way they did it in PREDIMED. Switch out or cut back on the cheap cheese, processed food, and beef — and reward yourself with a drizzle of good olive oil.

 

Roll Them All Into One

The next section argues that “Olive oil, in and of itself, does not lower LDL cholesterol,” and in the process rolls together several of the half-truths and failures of logic already put forward in the rest of the piece. First, it once again lays out a false dichotomy: olive oil against beans for lower LDL cholesterol. While it’s culinarily and nutritionally reasonable to talk about choosing amongst butter, coconut oil, seed oils, and premium EVOO in your cooking, you can’t really switch out beans for butter in a recipe. Rather, you’re going to serve beans cooked or drizzled with some source of fat to enhance their flavor and mouth feel, and the question is which fat source you’re going to pick.

Second, it’s true that olive oil only lowers LDL to the extent that it replaces saturated fat in the diet, but the distinction just doesn’t mean anything in practice for most people. If I start putting olive oil on my steamed vegetables instead of butter, and start using soffrito with olive oil as the base of my recipes instead of lard, my LDL is going to go down, whether or not olive oil “in and of itself” lowers LDL

Third, our level of LDL cholesterol isn’t the only thing that determines our risk of heart attacks. When subjects consume the kind of very low-fat, high-carbohydrate diet advocated by the author (complete with high levels of soy and other beans, fiber, fruits, and vegetables, and even three hours of aerobic exercise a week), their “bad” LDL cholesterol does go down — but so does their protective HDL cholesterol, and levels of harmful triglycerides rise.[35] Similarly, when people add monounsaturated fats to a more moderately low-fat diet with the same cholesterol-lowering foods, their LDL goes down just as much as it does on the low-fat version of the diet — but their inflammatory C-reactive protein goes down further, and their HDL levels go up.[36]

Additionally, although olive oil has little effect on the total amount of LDL circulating in your bloodstream, that isn’t the end of the LDL story, because high-phenolic olive oil does lower the most harmful fraction of LDL: the part that is damaged by free radicals (oxidized), making it much more likely to stick in your arteries and set you up for cardiovascular disease[2][3][4][5][6][7][8][9]. By contrast, lowering one’s fat intake actually raises the level of this extra-harmful LDL,[37][38] robbing you of much of the benefit you would expect to get just by looking at the effect on the total amount.

But (our author will protest again) there’s phenolics in fruits and vegetables, too! So wouldn’t a low-fat diet loaded with fruit and vegetables provide the same protection as high-phenolic olive oil? As it happens, this idea has been tested — and the answer appears to be no. In one study, scientists fed a group of women each of two moderately low-fat diets in alternating sequence. One diet contained two servings each of fruits and of vegetables a day, similar to the womens’ regular diet, but with lower intake of total and saturated fat. The other diet was just as low in fat, but contained 4 to 5 portions of fruit or berries and 5 to 6 portions of vegetables a day.

When the women lowered their fat intake without changing their intake of fruits and vegetables, their oxidized LDL levels shot up 27%. Loading up on fruit, berries, and vegetables as part of the same lower-fat diet blunted the harmful effect on their oxidized LDL, but still left them with higher levels of oxidized LDL than the levels they had started out with on their higher-fat, lower-vegetable default diets.[37] As we reviewed earlier, different phenolics in different food matrixes, consumed as part of different dietary patterns, have different effects on your health.

But maybe this is getting too far into the brush. Ultimately, the only reason we worry about LDL cholesterol — or oxidized LDL cholesterol, or triglycerides, or HDL, or other risk factor — is because of its ultimate effect on our health. And it’s already been proven in a massive clinical trial that consuming a high-phenolic olive oil Mediterranean diet cuts major cardiovascular events by 30%! A food doesn’t have to impact every single cardiovascular risk factor in order to be healthy — particularly because other components of a healthy diet can take care of the “residual risk.” We can join the article’s author for a healthy serving of Spanish white beans with spinach and sun-dried tomatoes, and still maximize the benefits and flavor with a splash of EVOO.

 

(Hydroxytyrosol molecule, reproduced under Creative Commons License from Wikipedia)

 

(Hydroxytyrosol molecule, reproduced under Creative Commons License from Wikipedia)



Notes


[1] Estruch R, Ros E, Salas-Salvadó J, Covas MI, Corella D, Arós F, Gómez-Gracia E, Ruiz-Gutiérrez V, Fiol M, Lapetra J, Lamuela-Raventos RM, Serra-Majem L, Pintó X, Basora J, Muñoz MA, Sorlí JV, Martínez JA, Martínez-González MA; PREDIMED Study Investigators. Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med. 2013 Apr 4;368(14):1279-90. doi: 10.1056/NEJMoa1200303. Epub 2013 Feb 25. PubMed PMID: 23432189.

[2] Moreno-Luna R, Muñoz-Hernandez R, Miranda ML, Costa AF, Jimenez-Jimenez L, Vallejo-Vaz AJ, Muriana FJ, Villar J, Stiefel P. Olive oil polyphenols decrease blood pressure and improve endothelial function in young women with mild hypertension. Am J Hypertens. 2012 Dec;25(12):1299-304. doi: 10.1038/ajh.2012.128. Epub 2012 Aug 23. PubMed PMID: 22914255.

[3] de la Torre-Carbot K, Chávez-Servín JL, Jaúregui O, Castellote AI, Lamuela-Raventós RM, Nurmi T, Poulsen HE, Gaddi AV, Kaikkonen J, Zunft HF, Kiesewetter H, Fitó M, Covas MI, López-Sabater MC. Elevated circulating LDL phenol levels in men who consumed virgin rather than refined olive oil are associated with less oxidation of plasma LDL. J Nutr. 2010 Mar;140(3):501-8. doi: 10.3945/jn.109.112912. Epub 2010 Jan 20. PubMed PMID: 20089783.

[4] de la Torre-Carbot K, Chávez-Servín JL, Jaúregui O, Castellote AI, Lamuela-Raventós RM, Nurmi T, Poulsen HE, Gaddi AV, Kaikkonen J, Zunft HF, Kiesewetter H, Fitó M, Covas MI, López-Sabater MC. Elevated circulating LDL phenol levels in men who consumed virgin rather than refined olive oil are associated with less oxidation of plasma LDL. J Nutr. 2010 Mar;140(3):501-8. doi: 10.3945/jn.109.112912. Epub 2010 Jan 20. PubMed PMID: 20089783.

[5] Gimeno E, de la Torre-Carbot K, Lamuela-Raventós RM, Castellote AI, Fitó M, de la Torre R, Covas MI, López-Sabater MC. Changes in the phenolic content of low density lipoprotein after olive oil consumption in men. A randomized crossover controlled trial. Br J Nutr. 2007 Dec;98(6):1243-50. Epub 2007 Jul 9. PubMed PMID: 17617938.

[6] Covas MI, Nyyssönen K, Poulsen HE, Kaikkonen J, Zunft HJ, Kiesewetter H, Gaddi A, de la Torre R, Mursu J, Bäumler H, Nascetti S, Salonen JT, Fitó M, Virtanen J, Marrugat J; EUROLIVE Study Group. The effect of polyphenols in olive oil on heart disease risk factors: a randomized trial. Ann Intern Med. 2006 Sep 5;145(5):333-41. PubMed PMID: 16954359.

[7] Fitó M, Cladellas M, de la Torre R, Martí J, Alcántara M, Pujadas-Bastardes M, Marrugat J, Bruguera J, López-Sabater MC, Vila J, Covas MI; members of the SOLOS Investigators. Antioxidant effect of virgin olive oil in patients with stable coronary heart disease: a randomized, crossover, controlled, clinical trial. Atherosclerosis. 2005 Jul;181(1):149-58. Epub 2005 Feb 12. PubMed PMID: 15939067.

[8] Weinbrenner T, Fitó M, de la Torre R, Saez GT, Rijken P, Tormos C, Coolen S, Albaladejo MF, Abanades S, Schroder H, Marrugat J, Covas MI. Olive oils high in phenolic compounds modulate oxidative/antioxidative status in men. J Nutr. 2004 Sep;134(9):2314-21. PubMed PMID: 15333722.

[9] Marrugat J, Covas MI, Fitó M, Schröder H, Miró-Casas E, Gimeno E, López-Sabater MC, de la Torre R, Farré M; SOLOS Investigators. Effects of differing phenolic content in dietary olive oils on lipids and LDL oxidation--a randomized controlled trial. Eur J Nutr. 2004 Jun;43(3):140-7. Epub 2004 Jan 6. PubMed PMID: 15168036.

[10] Llorente-Cortés V, Estruch R, Mena MP, Ros E, González MA, Fitó M, Lamuela-Raventós RM, Badimon L. Effect of Mediterranean diet on the expression of pro-atherogenic genes in a population at high cardiovascular risk. Atherosclerosis. 2010 Feb;208(2):442-50. doi: 10.1016/j.atherosclerosis.2009.08.004. Epub 2009 Aug 8. PubMed PMID: 19712933.

[11] Ruano J, López-Miranda J, de la Torre R, Delgado-Lista J, Fernández J, Caballero J, Covas MI, Jiménez Y, Pérez-Martínez P, Marín C, Fuentes F, Pérez-Jiménez F. Intake of phenol-rich virgin olive oil improves the postprandial prothrombotic profile in hypercholesterolemic patients. Am J Clin Nutr. 2007 Aug;86(2):341-6. PubMed PMID: 17684203.

[12] Personal communication, Dr. Maria Isabel Covas, 2013/07/23.

[13] Personal communication, Dr. Walter Willett, 2013/09/23

[14] Katan MB. Omega-6 polyunsaturated fatty acids and coronary heart disease. Am J Clin Nutr. 2009 May;89(5):1283-4. Epub 2009 Mar 25. PubMed PMID: 19321556.

[15] Buckland G, Travier N, Barricarte A, Ardanaz E, Moreno-Iribas C, Sánchez MJ, Molina-Montes E, Chirlaque MD, Huerta JM, Navarro C, Redondo ML, Amiano P, Dorronsoro M, Larrañaga N, Gonzalez CA. Olive oil intake and CHD in the European Prospective Investigation into Cancer and Nutrition Spanish cohort. Br J Nutr. 2012 Dec 14;108(11):2075-82. doi: 10.1017/S000711451200298X. Epub 2012 Sep 25. PubMed PMID: 23006416.

[16] Fernández-Jarne E, Martínez-Losa E, Prado-Santamaría M, Brugarolas-Brufau C, Serrano-Martínez M, Martínez-González MA. Risk of first non-fatal myocardial infarction negatively associated with olive oil consumption: a case-control study in Spain. Int J Epidemiol. 2002 Apr;31(2):474-80. PubMed PMID: 11980820.

[17] Trichopoulou A, Bamia C, Trichopoulos D. Anatomy of health effects of Mediterranean diet: Greek EPIC prospective cohort study. BMJ. 2009 Jun 23;338:b2337. doi: 10.1136/bmj.b2337. PubMed PMID: 19549997; PubMed Central PMCID: PMC3272659.

[18] Buckland G, Mayén AL, Agudo A, Travier N, Navarro C, Huerta JM, Chirlaque MD, Barricarte A, Ardanaz E, Moreno-Iribas C, Marin P, Quirós JR, Redondo ML, Amiano P, Dorronsoro M, Arriola L, Molina E, Sanchez MJ, Gonzalez CA. Olive oil intake and mortality within the Spanish population (EPIC-Spain). Am J Clin Nutr. 2012 Jul;96(1):142-9. doi: 10.3945/ajcn.111.024216. Epub 2012 May 30. PubMed PMID: 22648725.

[19] Barzi F, Woodward M, Marfisi RM, Tavazzi L, Valagussa F, Marchioli R; GISSI-Prevenzione Investigators. Mediterranean diet and all-causes mortality after myocardial infarction: results from the GISSI-Prevenzione trial. Eur J Clin Nutr. 2003 Apr;57(4):604-11. Erratum in: Eur J Clin Nutr. 2003 Aug;57(8):1034. PubMed PMID: 12700623.

[20] Solfrizzi V, D'Introno A, Colacicco AM, Capurso C, Palasciano R, Capurso S, Torres F, Capurso A, Panza F. Unsaturated fatty acids intake and all-causes mortality: a 8.5-year follow-up of the Italian Longitudinal Study on Aging. Exp Gerontol. 2005 Apr;40(4):335-43. PubMed PMID: 15820615. In this study cohort, “85% of [monounsaturated fatty acid intake] derived from olive oil.”

[21] Visioli F, Galli C, Grande S, Colonnelli K, Patelli C, Galli G, Caruso D. Hydroxytyrosol excretion differs between rats and humans and depends on the vehicle of administration. J Nutr. 2003 Aug;133(8):2612-5. PubMed PMID: 12888646.

[22] Maiani G, Castón MJ, Catasta G, Toti E, Cambrodón IG, Bysted A, Granado-Lorencio F, Olmedilla-Alonso B, Knuthsen P, Valoti M, Böhm V, Mayer-Miebach E, Behsnilian D, Schlemmer U. Carotenoids: actual knowledge on food sources, intakes, stability and bioavailability and their protective role in humans. Mol Nutr Food Res. 2009 Sep;53 Suppl 2:S194-218. doi: 10.1002/mnfr.200800053. Review. PubMed PMID: 19035552.

[23] Lakshminarayana R, Baskaran V. Influence of olive oil on the bioavailability of carotenoids. Eur J Lipid Sci Technol. 2013 Oct;115(10):1085–1093. DOI:10.1002/ejlt.201200254

[24] Brown MJ, Ferruzzi MG, Nguyen ML, Cooper DA, Eldridge AL, Schwartz SJ, White WS. Carotenoid bioavailability is higher from salads ingested with full-fat than with fat-reduced salad dressings as measured with electrochemical detection. Am J Clin Nutr. 2004 Aug;80(2):396-403. PubMed PMID: 15277161.

[25] Unlu NZ, Bohn T, Clinton SK, Schwartz SJ. Carotenoid absorption from salad and salsa by humans is enhanced by the addition of avocado or avocado oil. J Nutr. 2005 Mar;135(3):431-6. PubMed PMID: 15735074.

[26] Fielding JM, Rowley KG, Cooper P, O' Dea K. Increases in plasma lycopene concentration after consumption of tomatoes cooked with olive oil. Asia Pac J Clin Nutr. 2005;14(2):131-6. PubMed PMID: 15927929.

[27] Goltz SR, Campbell WW, Chitchumroonchokchai C, Failla ML, Ferruzzi MG. Meal triacylglycerol profile modulates postprandial absorption of carotenoids in humans. Mol Nutr Food Res. 2012 Jun;56(6):866-77. doi: 10.1002/mnfr.201100687. PubMed PMID: 22707262.

[28] Fielding JM, Li D, Stockmann R, Sinclair AJ. The effect of different plant oils used in preparing tomato sauces on plasma concentrations of lycopene and oxidative status: a dietary intervention study. Asia Pac J Clin Nutr. 2004;13(Suppl):S49. Supplementary information provided by Dr. Andrew Sinclair, 2010/08/10.

[29] Dewanto V, Wu X, Adom KK, Liu RH. Thermal processing enhances the nutritional value of tomatoes by increasing total antioxidant activity. J Agric Food Chem. 2002 May 8;50(10):3010-4. PubMed PMID: 11982434.

[30] Shi J, Le Maguer M. Lycopene in tomatoes: chemical and physical properties affected by food processing. Crit Rev Biotechnol. 2000;20(4):293-334. Review. PubMed PMID: 11192026.

[31] Takeoka GR, Dao L, Flessa S, Gillespie DM, Jewell WT, Huebner B, Bertow D, Ebeler SE. Processing effects on lycopene content and antioxidant activity of tomatoes. J Agric Food Chem. 2001 Aug;49(8):3713-7. PubMed PMID: 11513653.

[32] Mayeaux M, Xu Z, King JM, Prinyawiwatkul W.Effects of Cooking Conditions on the Lycopene Content in Tomatoes. J Food Sci. 2006 Oct;71(8):C461–C464. DOI: 10.1111/j.1750-3841.2006.00163.x

[33] Dewanto V, Wu X, Adom KK, Liu RH. Thermal processing enhances the nutritional value of tomatoes by increasing total antioxidant activity. J Agric Food Chem. 2002 May 8;50(10):3010-4. PubMed PMID: 11982434.

[34] Ajmera S. The effects of different cooking times and temperatures on tomato sauce lycopene content. A Thesis Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements for the degree of Master Of Family Consumer Sciences. December 2006

[35] Marshall DA, Vernalis MN, Remaley AT, Walizer EM, Scally JP, Taylor AJ. The role of exercise in modulating the impact of an ultralow-fat diet on serum lipids and apolipoproteins in patients with or at risk for coronary artery disease. Am Heart J. 2006 Feb;151(2):484-91. PubMed PMID: 16442919.

[36] Jenkins DJ, Chiavaroli L, Wong JM, Kendall C, Lewis GF, Vidgen E, Connelly PW, Leiter LA, Josse RG, Lamarche B. Adding monounsaturated fatty acids to a dietary portfolio of cholesterol-lowering foods in hypercholesterolemia. CMAJ. 2010 Dec 14;182(18):1961-7. doi: 10.1503/cmaj.092128. Epub 2010 Nov 1. PubMed PMID: 21041432; PubMed Central PMCID: PMC3001502.

[37] Faghihnia N, Tsimikas S, Miller ER, Witztum JL, Krauss RM. Changes in lipoprotein(a), oxidized phospholipids, and LDL subclasses with a low-fat high-carbohydrate diet. J Lipid Res. 2010 Nov;51(11):3324-30. doi: 10.1194/jlr.M005769. Epub 2010 Aug 16. PubMed PMID: 20713651; PubMed Central PMCID: PMC2952573.

[38] Silaste ML, Rantala M, Alfthan G, Aro A, Witztum JL, Kesäniemi YA, Hörkkö S. Changes in dietary fat intake alter plasma levels of oxidized low-density lipoprotein and lipoprotein(a). Arterioscler Thromb Vasc Biol. 2004 Mar;24(3):498-503. Epub 2004 Jan 22. PubMed PMID: 14739118.

 

Comments

To be honest I don't think

To be honest I don't think *ANY* natural fat (such olive oil, unprocessed lard or tallow, etc.) should be lumped in with trans fats.) I don't allow these things to bother me anyway. I ignore ridiculous scientific studies with an agenda. I will continue to love and eat my extra virgin olive oil on a regular basis.

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