Gayatri Acharya, MD: Greetings, I'm Dr Gayatri Acharya, cardiology fellow at Mayo Clinic. During today's recording, we'll be discussing the link between diet and cardiovascular health. I'm joined by my colleagues, Dr Steve Kopecky and Dr Robert Frantz, who are experts in this area. Welcome.
Stephen Kopecky, MD: Thank you.
Robert Frantz, MD: Thanks, good to be here.
Dr Acharya: Great to have you. Dr Kopecky, can you describe for us the historical context and the epidemiology of this discussion between diet and cardiovascular health?
Dr Kopecky: It's very interesting. It started over 5 decades ago with Ancel Keys [and his colleagues who conducted] the Seven Countries Study in Europe and the US and showed evidence that eating a diet high in saturated fat increased cardiovascular mortality. At the time, some investigators in Mediterranean nations—Greece and Italy—said, "Don't forget about the monounsaturated fats we're eating a lot of here," because most people at that time around the world did not eat olive oil. (In fact, in Britain and the US, we ate maybe an ounce a day. In comparison to now, it was very little.) That's where the link between saturated fat [and cardiovascular health] started, and it has been very hard to lose that over the years.
Dr Acharya: Dr Frantz, any additional comments?
Following in My Father's Footsteps
Dr Frantz: For me, this area is both personal and professional. My father was a lipid researcher who made his career in that area. I've lived this, and I suppose some of my credibility in this area has to do with the fact that my mother lived to 98 and my father into his 90s. Whatever they did seemed to work.
I remember, from a young age, my father explaining that people who came to the United States and adopted a Western diet [saw their] cardiovascular risk [rise] in a way that was different from their origins and seemed to reflect, in some sense, the dietary habits that they had picked up in Western society.
Dr Acharya: Dr Frantz, can you tell us more about your father, Dr Ivan Frantz, and his project on the Minnesota Coronary Experiment?
Dr Frantz: In the 1960s and '70s, there was a lot of interest in cholesterol-lowering diets that were low in saturated fat and whether we could translate findings from animal models into societal gains in terms of [lowered] cardiovascular risk. My father did a lot of research early on separating lipid fractions and understanding the meaning of high-density lipoprotein (HDL) and low-density lipoprotein (LDL) and then animal studies investigating diets that could lower lipid profiles in animal models. He [subsequently] worked on the Minnesota Coronary Experiment, which aimed to translate this into [humans via] a large study of diet [designed] to reduce cholesterol and cardiovascular risk.
He worked on that project for many years and, in fact, the diet was quite effective in lowering cholesterol. It was actually the largest well-controlled diet study ever done but, in fact, it was a neutral study in that it did not demonstrate a significant reduction in risk overall, despite the fact that [the diet] did effectively lower cholesterol. That was very disappointing.
More recent work led by Dr Chris Ramsden, a researcher at the National Institutes of Health (NIH) [suggests that part of the reason for the neutrality was] how the cholesterol was lowered. In fact, those diets used in the [original] study were high in linoleic acid, which is an essential amino acid but may be proinflammatory when it's heated and broken down. That gets us to this whole issue that it's not only about saturated fat but it's also about the effects of proinflammatory antioxidants and other parameters in the diet.
Lowering Cardiovascular Events With Diet
Dr Acharya: Dr Kopecky, on that topic, what eating styles do lower cardiovascular death and events?
Dr Kopecky: There have been three diets that we have names for that have lowered cardiovascular events. One is Ornish's—that was one of the early diets very low in fat. The second was the [Dietary Approaches to Stop Hypertension] DASH diet, which is more fruits and vegetables, and the third is the Mediterranean diet. What these have in common, especially the DASH and the Mediterranean, is [a focus on] fruits and vegetables, olive oils. Dr Frantz mentioned the proinflammatory effects that may be present in corn oils. Olive oil, actually, has very anti-inflammatory effects.
Dr Acharya: One of the questions I get in clinic all the time from my patients is—should we go high-fat/low-carb or low-fat/high-carb? How do we make sense of this for our patients? Dr Frantz?
Dr Frantz: The concept of high-glycemic-index foods—that are yanking our insulin levels around and may have both negative effects on our cardiovascular system and also our appetite—is relatively appealing. Limiting high-glycemic-index carbohydrates makes good sense. Epidemiologically, it makes sense if you consider the Mediterranean diet and [similar diets that are] relatively modest in high-glycemic-index foods.
We need to avoid [encouraging] the concept that saturated fat is okay in large amounts. I don't think that's true, in the sense that a diet that is low in saturated fat is a healthy diet. But it is very important how you replace that saturated fat, and Dr Kopecky could probably speak further to that.
Dr Kopecky: That is a good point, Bob, and there are two issues. One is [concerning] high-carb/low-carb. Any low-carb/high-fat diet increases your total mortality and your cardiovascular mortality. If you divide a low-carb diet up into two groups: an animal-based low-carb vs a plant-based low-carb—you go to the hamburger store, you throw away the bun, but eat the beef burger; that type of diet—will increase your cardiovascular and all-cause mortality by 20% to 25%. In contrast, eating a plant-based will lower it significantly. The key is to eat more plant, less animal.
The other [point] that Bob mentioned was that [commonly consumed] processed oils—canola oil, corn oil, and other polyunsaturated oils—are proinflammatory. [In contrast], olive oil is anti-inflammatory. About 56% of the calories we [Americans] consume is from processed foods, mainly seven subsidized groups—dairy, livestock, corn, soybeans, wheat, sorghum, and others. Those foods increase our risk of obesity, heart disease, and diabetes. So the other thing is the processed foods that we need avoid.
Highly Processed Oils and Other Foods
Dr Frantz: The concentration of calories in processed foods can be quite high, and an advantage of the plant-based diets is that the calorie density is lower. A favorite thing that I do is roast vegetables. They're good, they pick up a certain sweetness as they roast. They are high in fiber and varied in their other content, and they're relatively low-calorie.
Dr Kopecky: And you put olive oil on them.
Dr Acharya: Dr Kopecky, another follow-up question is we get asked a lot—what about heating olive oil? Are there other heart-healthy oils that we can cook with?
Dr Kopecky: A patient asked me that the other day. He said, "Doctor, you tell me to eat olive oil, but when I fry with it, doesn't it break down?" I said, "That's the point, don't eat fried foods." Frying foods puts all that fat onto the surface of the food, and we need to avoid that.
Dr Acharya: We hear a lot about fad diets, most recently, the MIND diet for Alzheimer's. Can you speak to that?
Dr Kopecky: The MIND diet is very clever. It's the Mediterranean and DASH combined. It's fruits and vegetables and lower-sodium foods. It's been shown to reduce [risk for] Alzheimer's, as has the Mediterranean diet. It also reduces [risk for] erectile dysfunction, diabetes, Parkinson's disease, arthritis, heart attack, stroke, and so on. The Mediterranean diet is the basis for all of that.
Dr Acharya: We talked about fried foods, but another huge food group that's a culprit here would be processed foods. How do we sort out which processed foods we should or should not be eating? Dr Frantz?
Dr Frantz: I try to stay away from them, especially if they're quite calorie-dense. A lot of these are manufactured and processed in a way that picks up a lot of oil and fat and potentially uses oils that, when heated, may be proinflammatory. I think it's important just to stay away from many of these processed foods to the extent that we can.
Dr Kopecky: I would agree. We've done a disservice to our patients as a profession by saying things like eat less saturated fat and more polyunsaturated fats. It's a complex message to understand. In contrast, it is easier to understand an apple, a banana, almonds, fish, etc. If it's a whole food, then eat that. If it's out of a box or out of some sort of a premade package, then avoid it because, as Dr Frantz said, [highly processed foods] contain oils and other [ingredients] that aren't [heart-healthy].
Practical Advice for Patients
Dr Acharya: To that point, I find that my patients are challenged sorting through the recommendations from well-established health groups. Are there any specific recommendations we should guide them toward, Dr Frantz or Dr Kopecky?
Dr Frantz: The move toward more plant-based foods and the Mediterranean aspects in terms of nuts, olive oil. Fruits, in general, are potentially more neutral, especially those that provide a big sugar boost. I sometimes see patients who are trying hard to change their habits, and they're eating a large amount of fruit. Depending on what kind of fruit it is, it may have a lot of sugar in it. I'm not sure that's actually healthy.
Dr Kopecky: I try to tell patients to avoid the tropical fruits. If it grows in Minnesota, you can eat it. But papayas, mangoes, bananas, and pineapples have a lot of sugar.
We've put together a booklet that has "10 Dos and Four Don'ts." Three of the 10 Dos are based on olive oil. The others [encourage] fruits, vegetables, legumes (anything that breaks in half is a legume, a bean), fish, white-meat poultry. We explain to patients that anything that's not light meat—a dark meat or light meat with the skin on—that's a saturated fat. They should only get a [portion the size of a] deck of cards per day.
The other foods to avoid are red meats, which is basically everything else. [Protein should be plant-based] or light-meat chicken. Try to stay away from anything out of a box. [Regarding dairy], a pat of butter a day [is acceptable], and you can find low-fat yogurts and low-fat milk.
We tell patients to try to migrate to the 10 dos, four don'ts over a couple of years, because we're human, we've done this for decades, and [it is difficult to] snap our fingers and say, "Tomorrow I'm going to eat this way."
Dr Frantz: I like the concept of "nudging." Or the Mark Twainism that you can't throw bad habits out the window; you have to coax them down the stairs one at a time. I think it's easy for us, our patients, and our families to get overwhelmed by these dietary recommendations and give up. But you can nudge yourself: Have fish 1 more day a week. Or when you [take a trip] to the grocery store, don't go hungry, and don't pick up those snack foods.
The concept of snacking, in a way, is contrary to the way evolution occurred. People don't need to eat as many times a day as they do. If you're working on something and unconsciously eating—where before you know it you've [consumed] 400 or 500 calories—that is something that you can nudge yourself not to do.
Dr Kopecky: The "dessertification" of breakfast has been a real problem in this country. The other advice is to have the meat, have the beef. But cut a part of it out and fill it with beans or something or something that's healthier and eat the rest of it later.
Dr Acharya: To your point about the "dessertification" of our foods, I had a patient recently ask me, "How much sugar am I allowed to have?" Are there any specific guidelines there?
Dr Kopecky: That's a good question. I'll ask patients, "How much are you eating now?" And they have absolutely no idea. That's why we have to talk to them more about fruits, vegetables, meats, dairy—food they can understand and see on a plate. But you do not [necessarily] know how much sugar or protein or how many calories are [on your plate].
Dr Frantz: It's true, although when buying yogurt at the grocery store, I'll pick up four different yogurt [products to compare the] carbohydrate and the calorie content. Is this yogurt with tremendously less sugar and fewer calories really going to taste that much different from that one? So sometimes, it's not about trying to add up the [sugar or calories] over the total day but instead making choices between two relatively comparable foods, one of which is clearly healthier than the other.
Do Statins Negate a Poor Diet?
Dr Acharya: One final question is statins. Does a statin negate what you eat each day? Dr Frantz, do you have any thoughts?
Dr Frantz: There's no such thing as a free lunch. It is natural to say, "I don't want to deal with diet. Just give me a statin and when my blood pressure goes up because I'm eating way too much salt, give me something for my blood pressure. And when my blood sugar rises and I'm diabetic, give me something for my diabetes." It doesn't work that way, does it?
Dr Kopecky: Unfortunately, it doesn't. Studies have shown that 40% of people who are not eating a healthy diet (as assessed by the modified healthy eating index) get no benefit from a statin at all—meaning no reduction in their cardiovascular morbidity and mortality.[10,11]
The other [consideration] is fitness. If you're not fit but you are taking a statin, your benefit is also negated. All the benefit is really in individuals who are fit, meaning they can [handle] a certain workload on a treadmill or do certain activities to keep themselves in good cardiovascular fitness. So a statin does not negate poor diet or fitness, unfortunately.
Dr Frantz: We now have [wearable] devices that can help [motivate] us to be more active. Activity-monitoring sensors such as FitBit remind us that we aren't doing as much as we thought. We [can combine] an increase in activity levels with being more cautious with our dietary choices.
For the right patients, statins and other lipid-lowering therapies can be of enormous value. They can be extremely important, especially for patients who have familial hyperlipidemias and conditions that make it difficult to minimize cardiovascular risk.
It's the whole package. I like to remind myself of the expression that your body is a temple; don't desecrate the temple. It matters what you do to your body, and if we can just think a little bit more about that every day, we can be healthier.
Dr Acharya: This was a fantastic discussion. Thank you, Dr Frantz. Thank you, Dr Kopecky. And thank you for joining us on theheart.org on Medscape.
Cite this: Think Whole Food, Not 'Out of the Box' for Heart Healthy Diet - Medscape - Aug 22, 2017.