Why Sugar Main Cause of Heart Disease

Everything we thought we knew about nutrition and heart health may be wrong. Experts around the world are now looking at an unexpected culprit as the main cause of heart disease: sugar.
By Rachel Meltzer, RD

We’ve heard it so many times, it comes as naturally as looking both ways before you cross the street: Protecting your heart means cutting down on fatty, salty foods.
It’s a mantra made manifest by the easy-to-understand concept of blobs of fat floating about our bloodstream, and by the vision of heart-unhealthy public figures like Dick Cheney and pre-vegan Bill Clinton, towering symbols of political striation and enthusiastic cheeseburger consumption. But while your cardiologist is unlikely to be passing around gift certificates to the Cheesecake Factory, more and more heart experts are coming to realize that fat and salt are only part of the story. The real danger to our hearts may be sneakier. And sweeter.
For the first time, scientists have linked the amount of sugar in a person’s diet with her risk of dying from heart disease. People who ate between 17 and 21 percent of their calories from added sugar had a 38 percent higher risk of dying from heart disease, compared with people who consumed 8 percent or less of their calories from added sugar, according to a study recently published in the Journal of the American Medical Association.
The case against sugar is so compelling that last year the advisory panel that helps create the U.S. Dietary Guidelines eased up on its hardline stance against fat and cholesterol, recommending instead strong limits on added sugar (the government will release the official guidelines later this year). The group suggested that Americans limit added sugars to no more than 10 percent of daily calories (that’s 12.5 teaspoons for someone with a 2,000-calorie diet). The American Heart Association takes an even tougher position, recommending no more than 100 calories per day from added sugars or 6 teaspoons for women, and 150 calories (9 teaspoons) for men. On average, we now get 22 teaspoons per day.
But what exactly is “added sugar,” and why do experts suddenly believe that it’s a threat to your heart?

Sugar Shakedown

When they talk about sugar, heart experts aren’t talking about the stuff that we consume from eating whole foods. “Added sugars are contributed during the processing or preparation of foods and beverages,” says Rachel K. Johnson, PhD, RD, professor of nutrition at the University of Vermont. So lactose, the sugar naturally found in milk and dairy products, and fructose, the sugar that appears in fruit, don’t count. But ingredients that are used in foods to provide added sweetness and calories, from the much-maligned high-fructose corn syrup to healthier-sounding ones like agave, date syrup, cane sugar, and honey, are all considered added sugars.
But aren’t all sugars created equal? Not really, say experts. Even if added sugars and natural sugars are chemically similar, it’s more about the total package. Fructose, the sugar in fruits, seems to be the most problematic health-wise; however it’s generally considered to be harmful only in high concentrations. “It’s almost impossible to overconsume fructose by eating too much fruit,” says Johnson. Consider this: You’d need to eat five cups of strawberries to get the same amount of fructose as in one can of Coke.
Another major difference—the fiber in fruit helps to fill you up, slow down digestion, and prevent rapid blood sugar spikes. What’s more, fruit is also a rich source of disease-fighting vitamins and antioxidants. Here’s what you do want to limit: Fruit juice, which is devoid of fiber and leaves you with too much sugar and too little satisfaction. It also couldn’t hurt to moderate your portions of dried fruit, which is also easy to overdo—about ¼ cup is considered a serving size.
Bottom line: You don’t need to be afraid of a mango. That pumpkin spice latte is a whole other story.

A Spoonful of Trouble

You already knew the stuff wreaks havoc on your teeth, and isn’t doing anything to help your diabetes risk. Plus, those added calories are only adding to your waistline, without providing any substantial nutritional value in return. But did you know that added sugar:

Increases Your Blood Pressure

Sugar may be worse for your blood pressure than salt, according to a paper published in the journal Open Heart. Just a few weeks on a high-sucrose diet can increase both systolic and diastolic blood pressure. Another study found that for every additional sugar-sweetened beverage, risk of developing hypertension increased 8 percent. Too much sugar leads to higher insulin levels, which in turn activate the sympathetic nervous system and leads to increased blood pressure, according to James J. DiNicolantonio, PharmD, cardiovascular research scientist at Saint Luke’s Mid America Heart Institute in Kansas City, Missouri. “It may also cause sodium to accumulate within the cell, causing calcium to build up within the cell, leading to vasoconstriction and hypertension,” he says.

Messes with Your Cholesterol

Eating a diet high in added sugar can do a number on your blood lipid levels, according to a 2010 study published in the Journal of the American Medical Association. Adults who ate the most added sugar (an average of 46 teaspoons per day!) were more than three times as likely to have low good HDL cholesterol levels compared with people who kept the sweet stuff to a minimum, according to researchers at Emory University who analyzed the blood of more than 6,000 men and women. The scientists also found a link between eating more added sugar and an increased risk of elevated triglycerides.

Strains Your Heart Muscle

“Americans have increased their calorie intake over the past 30 years primarily in the form of carbohydrates and sugars,” says Johnson. And those 256 extra calories per day we consume in the form of added sugar are likely leading to weight gain, which may directly damage the heart, according to new research. Obese adults have elevated levels of an enzyme that indicates injured heart muscle, found researchers at Johns Hopkins University—demonstrating that long before a heart attack may occur, those carrying extra weight are experiencing damage directly to their hearts. And you don’t have to be gravely overweight for the damage to occur—the risk rose incrementally with BMI.

Shake the Sugar

Reducing the amount of added sugar can’t be that hard—can it? Well, certain high-sugar foods are obvious—Dr. Pepper, Twizzlers, and Ben & Jerry’s, natch. But an even bigger problem may be the sneaky sugar lurking where you least expect it. “It’s in everything—even seemingly healthy foods like salad dressing, whole-wheat breads, and tomato sauces,” says Brooke Alpert, RD, owner of B Nutritious and author of The Sugar Detox. What’s more, it’s impossible to find out how much added sugar a food contains by looking at the nutrition facts panel, since labels don’t distinguish between added sugars and naturally occurring ones.
So what can you do to cut the sugar? Here are six steps.

1. Read Labels

“There are more than 70 different names for sugar,” says Alpert. Scour the ingredients list on any packaged food you buy for words like sucrose, barley malt, beet sugar, brown rice syrup, agave, and cane juice.

2. Buy Plain

Flavored foods are often code for “sugar added.” If strawberry flavored Chobani yogurt packs 15 grams of sugars, there’s no way to tell how much is from added sugars and how much is from the naturally occurring lactose. Stick with the plain version, and it will be easy to see that all 4 grams of the sugars are supposed to be there. Add flavor with whole fruit—or really shake up your taste buds with a savory topping instead. “It’s the same idea as ordering dressing on the side. This way, you get to be in control of how much sweetness is added to your food,” says Alpert. (Hear are our 6 Fat-Burning Ways to Eat Yogurt.)

3. Drop Drinkable Sugar

“Almost half of Americans’ added sugars intake comes from drinks,” says Johnson. So for many people, limiting beverages like soda, iced teas, lemonade, and fruit punch is a simple way to cut back big time. And healthy-sounding drinks like kombucha and vitamin waters are no exception. Don’t forget about your Starbucks run, either, says Alpert. “Coffee and tea aren’t supposed to be dessert.” Try one of these 14 Detox Waters instead.

4. Skip Juices and Smoothies

Without fiber to buffer the sugar load, the natural fructose in, say, an orange, is a very different animal. A cup of juice can be equivalent to about four oranges—an amount you’d be pretty unlikely to eat in whole-fruit form. As for smoothies, they’re a step in the right direction since they contain the whole fruit—but research from Purdue University found that liquid calories aren’t as filling as chewable ones. And by blending fruit into a pulp, it’s easy to get more fructose than you’re bargaining for.

5. Cut the Condiments

Add-ons like ketchup, barbecue sauce, flavored vinegars, and some mustards (like honey mustards) can be loaded with sweetener. If you’re going to dress up your meal, read labels to be certain there are no surprises—Dijon mustard, apple cider vinegar, and hot sauce are usually good options. Or use produce: Pineapple salsa, Vidalia onions, and tomatoes are all simple additive-free ways of sweetening a plate.

6. Add Herbs, Spices, and Extracts

They’re flavorful and low-calorie additions to any meal. “Cinnamon, vanilla, ginger, and nutmeg are some of my favorite “sweet” spices,” says Alpert, who recommends adding them to oatmeal, yogurt, or even nuts. “Bonus point—a lot of spices also help regulate your blood sugar levels and can even reduce the amount of AGEs (advanced glycated endproducts) that result from too much sugar in your bloodstream,” she adds

While there is a general agreement that sugar intake is bad for heart health, this was not always the case. In the 1960s, when deaths from heart disease in the United States reached a peak, researchers were divided on the primary dietary contributors to the condition: sugar or fat? For years, studies blamed the latter, but recent research suggests the sugar industry may have played a pivotal role in which way the finger was pointing.

Researchers have uncovered a 50-year-old heart disease study that was funded by the sugar industry to shift the blame from sugar to fat.

Earlier this month, dentist-turned-researcher Dr. Christin Kearns, of the University of California-San Francisco (UCSF), and colleagues reignited the debate over the influence the food industry has over scientific research.
In JAMA Internal Medicine, the team published a report revealing the discovery of a study published in the 1960s that received funding from the Sugar Association - formerly the Sugar Research Foundation (SRF).
The problem? The SRF funding was not disclosed - mandatory conflict of interest disclosure was not introduced until the 1980s - and there is evidence that the researchers of the 50-year-old study were paid to shift the focus away from the harms sugar intake poses for heart health.
The study in question was published in The New England Journal of Medicine on July 27, 1967.
Conducted by three former nutritionists at Harvard Medical School in Boston, MA - Dr. Frederick Stare, Dr. Mark Hegsted, and Dr. Robert B. McGandy, who are now deceased - the research claimed that consumption of dietary fats, rather than sugar, was the primary cause of coronary heart disease (CHD).

The landing of 'Project 226'

In their report, Dr. Kearns and colleagues reveal the discovery of documents in public archives that show Drs. Stare and Hegsted were paid $6,500 - the equivalent of almost $50,000 today - by the SRF to detract attention away from previous studies linking sugar to CHD.
According to the UCSF researchers, the documents show that in 1964, John Hickson - then president of the SRF - penned a memo suggesting the SRF "embark on a major program" in order to redress "negative attitudes towards sugar," and one way he proposed doing so was to fund research to "refute our detractors."
One year later, Hickson commissioned Dr. Hegsted and colleagues to conduct "Project 226" - described by Hickson as "a review article of the several papers which find some special metabolic peril in sucrose."
Hickson provided Dr. Hegsted with a number of papers, and according to Dr. Kearns and team, the Harvard researchers "heavily criticized" studies that identified a link between sucrose - or table sugar - and coronary heart disease, while disregarding the limitations of studies that associated fat with the condition.
The study's conclusion? That lowering intake of fat is the only way to keep cholesterol levels low and prevent CHD. This, therefore, would suggest to the general population and policymakers that a high-sugar diet does not play a major role in CHD.
Commenting on their discovery, Dr. Kearns and co-authors say:

"Together with other recent analyses of sugar industry documents, our findings suggest the industry sponsored a research program in the 1960s and 1970s that successfully cast doubt about the hazards of sucrose while promoting fat as the dietary culprit in CHD."

Speaking to Medical News Today, Dr. Kearns said she was "surprised to learn the SRF began funding heart disease research as early as 1965 - and that their tactics to shift the focus off of sucrose were so sophisticated."
Marion Nestle, a professor of nutrition and food studies at New York University, who wrote an editorial accompanying Dr. Kearns' report, told MNT she was "shocked" by the discovery.
"Everyone knew that Fred Stare collected scads of money from food and drug companies and sounded like he worked for the food industry, but Mark Hegsted was another matter," she said. "I knew him as a scientist committed to finding effective dietary approaches to chronic disease and would never have imagined him working so closely with the sugar industry."

The continued influence of one biased study

The new revelation demonstrates how the sugar industry skewed the results of one study almost 50 years ago, but how is this relevant today?
That single study is likely to have influenced our diets ever since; the results were used in SRF marketing, and they even helped inform recommendations relating to diet and heart disease, many of which remain.

The sugar industry-funded study is likely to have influenced what we have eaten for decades.

Stanton Glantz, co-author of the UCSF research, explains that the industry-funded study was a major review published in an influential journal, so it "helped shift the emphasis of the discussion away from sugar and onto fat."
"By doing that, it delayed the development of a scientific consensus on sugar-heart disease for decades," he adds.
Report co-author Laura Schmidt, of UCSF, notes that saturated fat has been perceived as the main culprit in heart disease for years, but increasingly, light is being shed on the role of sugar.
A study published in the journal Progress in Cardiovascular Diseases earlier this year, for example, presented evidence that added sugar intake might be an even greater contributor to cardiovascular disease than saturated fat.
"After a thorough analysis of the evidence it seems appropriate to recommend dietary guidelines shift focus away from recommendations to reduce saturated fat and towards recommendations to avoid added sugars," said Dr. James J. DiNicolantonio, of Saint Luke's Mid America Heart Institute and co-author of the study.
While evidence of sugar's major role in heart disease is mounting, Schmidt notes that "health policy documents are still inconsistent in citing heart disease risk as a health consequence of added sugars consumption."

Industry-funded studies remain a problem

Today, researchers are required to disclose any conflicts of interest they may have, including any industry relationships and funding they have received - a regulation that was not in place in the 1960s, and a fact that The Sugar Association use in their defense in response to the UCSF discovery.
"We acknowledge that the Sugar Research Foundation should have exercised greater transparency in all of its research activities, however, when the studies in question were published, funding disclosures and transparency standards were not the norm they are today," the organization comments.

In some cases, such as with drug development, industry-funded research is beneficial.

But has the introduction of transparency standards in the 1980s reduced how much influence industries have over scientific research? It seems not.
Take the tobacco industry, for example. In a study published in the journal Circulation in 2007, Glantz and colleagues combed through millions of tobacco industry documents, many of which revealed how the tobacco industry funded studies in the 1990s to play down the harms of secondhand smoke exposure, in an attempt to stave off smoke-free laws.
In relation to the food industry, just last year, the New York Times revealed that Coca-Cola was funding the development of a nonprofit organization called Global Energy Balance Network (GEBN).
While GEBN claimed its aim was to conduct research into the causes of obesity, the organization widely claimed that it is lack of exercise, rather than an unhealthy diet, that causes weight gain.
"Most of the focus in the popular media and in the scientific press is that they're eating too much, eating too much, eating too much, blaming fast food, blaming sugary drinks and so on. And there's really virtually no compelling evidence that that in fact is the cause," Steven N. Blair, a member GEBN's executive committee said in a promotional video.
"Those of us interested in science, public health, medicine, we have to learn how to get the right information out there."
On this occasion, it seems the proposal that an unhealthy diet is not a cause of obesity - a claim backed by a soft drink giant - was shunned by healthcare professionals and the general public alike; in November 2015, GEBN ceased operation.
Still, industry-funded research continues - but why? Can it ever be beneficial?

Industry-funded research should be interpreted with caution

One area of research that does benefit from industry funding is drug development.
While grants from government organizations and charities enable some drug trials to go ahead, in the U.S., the bulk of funding comes from the pharmaceutical industry, with more than $30 billion a year spent on drug development.
Without pharmaceutical industry funding, many of the drugs we use today for common illnesses may not have been discovered. But that is not to say such funding isn't problematic; it can result in bias, with numerous studies showing that trials funded by the pharmaceutical industry are more likely to support the interest of the sponsor.
And according to Nestle, this type of bias is very much present in research funded by the food industry.
"In my casual year-long collection of 168 industry-funded studies, I found 12 with results that did not favor the sponsor's interest. Systematic studies come out with slightly higher percentages of unfavorable studies," Nestle told MNT.

"The science is usually done pretty well; it's the research question and the interpretation that seem most influenced. Research shows that investigators who take industry funding are unaware of the influence and bias their science inadvertently. This makes the problem exceptionally difficult to deal with."

Marion Nestle

Is there anything that can be done to reduce the effects of bias from food industry-funded research?
According to Dr. Kearns and colleagues, their recent discovery suggests policymakers should "consider giving less weight to food industry-funded studies and include mechanistic and animal studies, as well as studies appraising the effect of added sugars on multiple CHD biomarkers and disease development."
In her editorial, Nestle says the results emphasize that caution should be applied when interpreting the results of research funded by the food industry.
"May it serve as a warning not only to policymakers, but also to researchers, clinicians, peer reviewers, journal editors, and journalists of the need to consider the harm to scientific credibility and public health when dealing with studies funded by food companies with vested interests in the results," she adds, "and to find better ways to fund such studies and to prevent, disclose and manage potentially conflicted interests."
It is evident that the recent discovery of the sugar industry's role in heart disease research has left a bitter taste in the mouths of nutritionists, policymakers, and the general public. Whether it has the ability to change approaches to food industry-funded research, however, remains to be seen.

Written by Honor Whiteman