Good Fats, Bad Fats, and Sugar: A ‘Big Picture’ Approach Is Warranted With Diet Interventions for Cardiovascular Disease
INNSBRUCK, Austria—While cardiovascular disease prevention studies have historically sided unequivocally for or against the consumption of specific foods as being good or bad for the heart, the common theme of an opening session at European Atherosclerosis Society Congress 2016 was that what matters most is overall nutrition.
“We shouldn’t be talking about individual nutrients,” said Alice Lichtenstein, DSc (Tufts University, Boston, MA). “We really need to be talking about dietary patterns.”
In her presentation, Lichtenstein focused on the ongoing controversy over saturated fats and their link with cardiovascular disease. “[This issue is] something that we thought we had settled in the 1960s, and it’s reemerged,” she said. “This has become very challenging for clinicians and also for individuals who feel that there’s sort of a ping-pong ball going back and forth as far as what they can do.”
Sensational magazine covers and newspaper headlines are driving a lot of the controversy around nutrition and heart disease, Lichtenstein commented, but many of these media stories are either misinformed or do not display the whole picture. A 2014 meta-analysis spurred much of the current debate around saturated fats as it went against current recommendations to replace them with polyunsaturated fats.
A lot of the data on which current guidelines are based are decades old, she acknowledged, but that doesn’t make them any less important or robust. For example, the 1968 study of soy bean oil as a replacement for saturated fats as well as the Los Angeles VA study of vegetable oil from the same year showed clear linear associations with saturated fat and adverse cardiovascular events.
After listing several more large trials, Lichtenstein commented on the current debate. “Why has this question reemerged about saturated fat?” she asked. A 2009 meta-analysis kicked things off by not only concluding that saturated fats and polyunsaturated fats have a weak association with coronary heart disease but also finding strong associations with the Mediterranean and Western diets—albeit in opposite directions—and outcomes. This started to get people thinking that individual foods don’t matter as much as dietary patterns, Lichtenstein said.
Clinicians are still combatting the main message the public received in the 1990s, namely that it is better to lower overall fat than to replace saturated fats with polyunsaturated fats, she continued. “That’s where we really got in trouble. . . . When you dramatically decrease the major sources of saturated fat in the diet, you also dramatically decrease the calories. However, when we started talking about low fat equals low calorie, then we got into problems because then we saw a proliferation of fat-free [junk] foods.”
The 2015 US dietary guidelines reflect a change in public perception. For the first time, Lichtenstein said, oils were segmented out to emphasize replacing saturated fats with polyunsaturated fats. “We thought it was more important than ever before to emphasize it’s really the type of fat, not the amount of fat,” she said.
For now, Lichtenstein said it’s about changing public perception. She told TCTMD that it is up to physicians to handle cases of patient confusion with each individual directly. Though it might seem obvious, physicians should tell their patients not to be “swayed by news reports that sound too good to be true, because they probably are too good to be true,” she said.
Also, it’s about explaining how to understand the scientific literature as a whole, according to Lichtenstein, rather than assuming science will unearth a magic bullet. “Don’t think that suddenly we [will] discover something totally new and different about diet,” she said.
Also speaking during the session, Jean Pierre Després, PhD (Laval University, Quebec City, Canada), focused on sugar, noting that confusion over how much and what kinds to include in an optimal diet is “not new.”
First, however, “we need to distinguish complex carbohydrates from the simple sugars—monosaccharides and disaccharides” and between naturally occurring and added sugars, he said, noting that of course added sugars have caused the most harm in contemporary populations. If the average person was very active, then the topic of added sugar would not be as big of a problem, Després said. But “because there are more physically inactive people than smokers [today], inactivity is responsible for more deaths worldwide than smoking. This is not a trivial issue,” he added.
Agreeing with Lichtenstein, Després said the approach of studying individual foods to detect associations with outcomes is a “recent phenomenon in the literature.” While several studies have been consistent in showing the benefits of a diet rich in items like nuts, whole grains, fruits, and fish, he said that this science needs to be better communicated.
“It should be more of ‘this,’ less of ‘that’—including sugars. We have been too technical in the past and our patients are completely confused when they read that a specific component of a diet is good or bad for heart health,” Després commented.
Specifically with regard to sugar-sweetened beverages, he explained that there is now enough evidence to support the fact that consuming more of them can directly increase passive caloric intake. On top of such a glucose load, this can lead to insulin resistance as well. Fructose, on the other hand, is “very, very controversial,” according to Després, as “some investigators have suggested that fructose in [sugar-sweetened beverages] could deplete intracellular ATP [and] increase uric acid production.” Regardless, it is clear that more dietary sugar equals more calories consumed, and “therefore this will contribute to deteriorating your cardiometabolic risk profile,” he said.
“We have this discussion with our patients all the time,” Després added. “One soft drink here and there because it’s a source of pleasure is fine. This is not incompatible with cardiometabolic health. It is the chronic overconsumption which is a problem, because it is a marker of poor nutritional quality.”
Future research and practice need to “go way beyond being lipid-centric or glucose-centric or whatever,” he concluded. “We need the full picture.”
Complementing Drugs With Diet
In a third presentation, John Chapman, PhD (Pitié-Salpêtrière Hospital, Paris, France), explored the role of plant sterols and stanols for lowering LDL cholesterol.
For both primary and secondary prevention, he said, statins have shown great success in lowering LDL cholesterol levels and, in so doing, lowering adverse events. However, statins can be associated with side effects, like muscle pain, or may simply not be sufficient to help patients reach specific LDL goals, Chapman noted.
“We are increasingly aware of the pharmacogenomic impact on statin response, which means that clinicians really must follow up with patients—as far as their response to statins—far more than we tend to do,” Chapman said, adding that there are also a number or parameters that “underlie the variability in the response of any statin at any dose.”
New PCSK9 inhibitors have been “markedly efficacious,” he observed, so the challenge now is to determine how best to combine new and established drug treatments with lifestyle and diet to attain LDL goals. “We actually have some very interesting choices from naturally occurring products,” Chapman said, referring to the plant sterols and stanols that are present in many foods like grains, nuts, and seeds and are now showing up in stores as additives to margarine, orange juice, and cereal. But as far as how much would need to be consumed to attain a significant LDL reduction, this depends on the diet as a whole.
Past research has shown that 2 g per day of plant sterols and stanols is not associated with harm, he explained, but the dose response relationship varies widely as with other good food products. “The value of roundabout a 10% [LDL] reduction in about 2 g per day consumption of these agents is fairly typical,” Champan said.
Additionally, the effects of plant sterols and stanols are complementary to those of ezetimibe. “Basically what we’re saying is that the order of magnitude that we could attain with these naturally occurring substances in enriched food products is absolutely relevant to the intervention strategies that we formulated in our guidelines with [European Society of Cardiology],” he said, adding that this route should only be considered for patients at very low risk. “But all of the other categories [of risk] qualify for lifestyle intervention and for dietary advice,” Chapman commented.
Lichtenstein AH. Should saturated fat be targeted for the prevention of cardiovascular disease? Presented at: European Atherosclerosis Society Congress 2016. May 29, 2016. Innsbruck, Austria.
Després JP. Sugar intake and cardiovascular disease – should it be the next fight to decrease CVD. Presented at: European Atherosclerosis Society Congress 2016. May 29, 2016. Innsbruck, Austria.
Chapman J. Plant sterol and stanols and cardiovascular disease: impact of enriched foods and cholesterol lowering drugs. Presented at: European Atherosclerosis Society Congress 2016. May 29, 2016. Innsbruck, Austria.
- Lichtenstein reports no relevant conflicts of interest.
- Després reports receiving research funding from, consulting to, and serving on the speakers bureaus for several pharmaceutical companies.
- Champan reports receiving research funding from CSL, Kowa, Merck, and Pfizer and serving on the advisory boards and speakers bureaus for Amgen, AstraZeneca, Kowa, Pfizer, and Sanofi-Regeneron.