New Study Suggests Sugar is Worse than Salt for Heart Disease

A recent study published in The BMJ* suggests that limiting sugar intake might be more effective than reducing sodium intake with respect to controlling hypertension, despite decades of advice from the medical establishment recommending low salt diets for hypertensive patients suffering from high blood pressure.  In the developed world, cardiovascular disease is the leading cause of premature death, and hypertension is the most common risk factor for heart disease, which costs the United States over $50 billion a year, and is therefore a prime focus for preventative care.

Efforts to control hypertension by reducing dietary sodium have frequently been called into question as successive studies on the subject have presented researchers with conflicting data. In fact, some studies have suggested that reducing sodium can have a negative effect on health, and lead to an increase in overall mortality. There is, however, one aspect of the low-salt diet that almost everybody agrees is beneficial, and that is that it reduces the amount of processed food that a patient can eat. There is little debate over the health benefits of reducing processed foods, which usually contain high amounts of sodium.

The Food and Drug Association (FDA) has recently announced that it will be drafting guidelines requesting that the food industry reduce the amount of sodium in processed foods voluntarily, thus adding to the confusion over salt, but sodium is not the only white crystal in processed foods. Processed food items also contain relatively large amounts of dietary sugars, including both ordinary table sugar as well as high-fructose corn syrup (HFCS).  Sucrose, or table sugar, is made up of equal amounts of two monosaccharides, fructose and glucose.  Food grade high-fructose corn syrup, as the name suggests, has higher amounts of fructose than it does glucose in a 55/45% ratio. As the researchers explained, fructose appears to be responsible for the more negative health effects of the sweetener.  Unlike glucose, which the body stores as fat and uses a fuel, fructose gets sent to the liver, where it is believed to cause a host of health problems, including diabetes, gout and cardiovascular diseases.

Three hundred years ago, when sugar was a rare and costly commodity,  the average human being consumed only a couple of pounds of sugar a year. Today, is it estimated that the average American consumes between 77 and 152 pounds of sugar on an annual basis. In their article, study authors James J DiNicolantonio and Sean C Lucan highlighted a study of American teenagers which concluded that, on average, teenage boys consume 389 grams of sugar on a daily basis! The problem here is not with the amount of calories teenagers are consuming, but rather an excess of calories from sugars and a deficit of calories from fat and protein.

This is less surprising when it is considered that, over the last 30 years, people have been told to reduce the fat in their diets. For many parents, the idea of eating low-fat is so ingrained that they believe they are doing the right thing when they buy reduced fat foods for their families, and give little thought to the sugar content of foods.

The general public has every right to be confused. Consumers are continually being presented with conflicting dietary advice. What to eat or what not to eat is a question that most consumers are unable to answer with confidence due to the amount of constantly changing advice they have received from doctors, nutritionists, talk show hosts, friends and neighbors over the years. The excited announcements by publicity-seeking scientists can change the behaviors of entire populations, as proven by the low-fat trends that started after Ancel Keys published the Severn Counties Study and labelled fat as the cause of heart disease. Key’s data has since been discredited, and there is a wealth of data in favor of eating moderate amounts of dietary fat, but most people are still under the influence of low-fat is best myth.

As the study pointed out, one of the problems created when salt was labelled the bad guy was that processed food producers began to develop and market “reduced salt” versions of products. In order to make these lower sodium variations palatable, they increased the amount of added sugars in such foods. Now, consumers are choosing low-salt versions in the belief that they are making good health decisions, but the reality is that they are probably consuming a greater amount of refined sugar, which is arguably a worse option in terms of cardiovascular wellness.

The study concluded that high-sugar diets may contribute significantly to cardiovascular disease. What the authors made very clear, was that this does not include naturally occurring sugars, which are neatly presented to us by nature in the form of whole foods. Artificially added sugars as found in processed foods were the focus of the researcher’s dietary suggestions, showing that the general advice to avoid processed foods is still relevant.

James J. DiNicolantonio, associate editor at The BMJ’s Open Heart, called sodium restriction “the greatest con in preventative nutrition in human history” in an interview this week. DiNicolantonio points out that dietary guidelines from the American Heart Association (AHA), which tell consumers to eat no more than 2.4 grams of sodium per day, completely ignore the scientific literature that points to an optimal intake of between three and four grams per day. DiNicolantonio says that the guidelines focus on the wrong white crystals, and should have focused on sugar rather than salt.

Salt has been under attack as a source of heart disease since 1904, when French doctors reported an anecdotal connection between salt intake and heart disease in a sample group of just six subjects, but the anti-salt movement really gained momentum in the 1970s when Dr. Lewis Dahl published studies indicating a relationship between salt intake and hypertension. The problem with Dahl’s research, according to a widely-quoted Scientific American article from 2011, was that Dahl fed his specially bred laboratory rats a diet equivalent to 500 grams of sodium per day, at a time when the average daily human consumption of sodium was 3.4 grams per day, which was 143 time the daily human consumption. To reach that level of salt consumption, a person would have to consume 90 teaspoons of salt per day.

Robert H. Eckel, who was a co-chair on the AHA’s guidelines writing panel, does not agree that the guidelines are misguided. He says that they were written based on well-founded research. The debate is a prime example of the bickering that takes place between health officials when it comes to dietary advice.

The take away message proposed by the study authors was that future dietary guidelines for consumers should focus on replacing refined processed foods with natural whole foods. At last, some advice that everyone can agree on!


(* The BMJ: The British Medical Journal  -ed)

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