Most consumers have been led to believe that fats, especially trans fats, are the primary culprits behind declining heart health in the United States. Recent studies though, have concluded that sugar may be even more detrimental to cardiovascular health than any kind of fat. The effects of sugar from direct intake and from starches, (which convert to sugar in the body once consumed) are now known to be major contributors to heart disease.
Studies on Sugar and Cardiovascular Health
In 2016, the Journal of the American Medical Association (JAMA) published a report that a major, influential 1967 study conducted by the New England Journal of Medicine was unduly influenced by the sugar industry. This report had set the tone for what constituted healthy consumption of sugars and blamed fat and cholesterol intake alone as the primary risk factors for heart related disease and death. As a direct precursor to life-threatening cardiovascular issues though, sugar was touted as being benign.
A recent study in JAMA, among others, definitively linked increased sugar intake to cardiovascular-related mortality. This study followed 40,000 participants and concluded that those with the highest sugar intake increased their risk of death from cardiovascular disease by 400%. This was true even after accounting for other risk factors such as age, weight, smoking, exercise, and alcohol consumption. The study also concluded that diets comprised of just 20% sugar double the risk of heart attack, even though the Institute of Medicine still recommends capping sugar intake at no more than 25% of daily calories consumed.
Another recent study by James DiNicolantonio, PharmD and James O’Keefe, MD, co-authored by Sean Lucan, MD, has also linked increased mortality from cardiovascular disease to excess sugar consumption. In Progress in Cardiovascular Diseases, the doctors reviewed studies dating back to the 1950s correlating cardiovascular disease to both sugar and fat intake. Their conclusion was that not only does sugar increase the incidence and mortality rate of cardiovascular disease, but that sugar intake played a larger role in heart-related disease and death than even saturated fat.
Scientists have also published works in the American Journal of Clinical Nutrition showing an increase in “bad” cholesterol and decrease in “good” cholesterol levels in research participants consuming higher levels of sugar. Additionally, participants showed higher levels of triglycerides, leading to higher incidences of heart attack and stroke. This and other similar studies further suggested that the way the body metabolizes sugar, combined with fat intake, and not fat intake alone, is one of several ways sugar affects heart health.
Indirectly, excess sugar, especially refined sugar, affects the heart by contributing to weight gain and diabetes. Both place extra strain on the heart that can eventually lead to heart failure. In addition, most diabetics in the United States suffer from diabetic cardiomyopathy, a condition where the heart muscle is weakened through excess sugar consumption, eventually losing its ability to pump blood on its own.
Even those not at risk for diabetes are at risk for sugar-related cardiovascular disease though. Sugar is linked to both high blood pressure and increased heart rate, both causing heart stress leading to earlier disease and death. Sugar has also been linked to elevated stickiness of blood platelets, a risk factor for blood clots and stroke. Furthermore, consumption of just two sugary beverages daily as a part of an otherwise healthy 2,000 calorie diet has been shown to increase the risk factor for cardiovascular-related death by 20%. As mentioned earlier, the amount of sugar consumed combined with how the body metabolizes fat also leads to excess strain on the heart.
Arteries of the heart are especially sensitive to sugar. One doctor likened sugar’s effect on arterial walls to sandpaper, slowly eroding and damaging the walls of the arteries until enough plaque has built up on the damaged walls to cause a heart attack. No matter how high a patient’s fat levels, plaque build-up does not occur without arterial wall damage, and sugar does just that.
Sugars from fruits and vegetables are not known to increase the risk of heart disease and death. Refined sugars, sugars from carbohydrates, and fructose and glucose added to processed foods are of primary concern. The American Heart Association recommends limiting sugar intake to 100 calories of sugar daily for women and 150 calories daily for men. Maintaining these limitations have now been shown to significantly improve health and lifespan.