Researchers followed more than 110,000 people for nine years and found that the more free sugar a person takes in, the greater the risk for heart disease (BMC Medicine, Feb 14, 2023;21(34)). Each five percent increase in free sugar intake in a participant’s daily diet resulted in a six percent higher risk of heart disease and a 10 percent higher risk of stroke. Furthermore, a higher fiber intake and replacing refined grain starch and free sugars with whole grains and non-free sugars appeared to help protect against heart attacks. The authors explained how increased intake of sugar-added foods and drinks can cause heart disease: Those who took in more sugar-added foods and drinks had higher blood triglycerides and greater waist circumferences.
Note: Free sugars are defined by these researchers as any sugars added to foods by the manufacturer, cook or consumer, plus sugars present in honey, syrups, and fruit juices. (Non-free sugars are those naturally occurring in fruit, vegetables, and dairy products). See How Eating and Drinking Sugar Can Cause Diabetes
This study agrees with many other studies that show that heart damage is associated with refined sugar intake, not the total amount of carbohydrates (Lancet, 2017;390:2050–62). An earlier review of studies on sugar-added foods shows that people who take in 10-25 percent of their calories from sugared beverages and foods suffer a 30 percent higher risk for heart attacks, compared with people who take less than ten percent of calories from added sugars (British Medical Journal: Open Heart, Dec. 11, 2014). The review also found that:
• higher added-sugar intake was associated with increases in systolic and diastolic blood pressure of 6.9 and 5.6 mm Hg
• the more sugared foods you eat, the higher your bad LDL cholesterol
Sugars occurring naturally in foods, such as fruit, did not appear to increase risk for high blood pressure or heart attacks. Another review of twelve scientifically-dependable studies involving 409,707 participants showed that sugar-sweetened beverages were associated with increased risk for high blood pressure, a major risk factor for diabetes and heart attacks (The American J of Cardiol, February 2014).
How Intake of Added Sugars Increases Heart Attack Risk
• Taking in sugar added foods and drinks causes a high rise in blood sugar.
• To prevent blood sugar from rising higher, the pancreas release insulin which lowers blood sugar by driving sugar from the bloodstream into the liver.
• As soon as the liver fills up with sugar, it can store no more sugar, so the extra sugar is converted by your liver into fatty triglycerides, so blood levels of triglycerides rise too high (>150).
• To prevent blood triglyceride levels from rising too high and causing clots, your good HDL cholesterol carries the triglycerides into the liver, so your HDL cholesterol goes down and you store extra fat in your liver to cause a fatty liver.
• As the liver collects extra fat, it cannot respond to insulin that lowers blood sugar by driving sugar from the bloodstream into the liver, so your blood sugar rises even higher and you have insulin-resistant diabetes.
• As the cycle continues, extra fat is deposited in the liver and the belly, which gives you a big belly.
• Then your liver takes large numbers of triglyceride molecules and combines them with lesser numbers of cholesterol molecules to make the bad LDL cholesterol, which causes plaques to form in arteries (arteriosclerosis), which can break off to lead to a heart attack.
How Can You Tell If You Are Insulin Resistant?
People who are insulin resistant usually have what is called metabolic syndrome. You probably have metabolic syndrome if you have three or more of:
• storing fat primarily in your belly
• small hips compared to your stomach
• being overweight
• blood triglycerides >150
• HDL cholesterol <40
• high blood pressure
• a fatty liver
• fasting blood sugar >100
• HbA1c >5.7
• high insulin levels
Treat Insulin Resistance with Lifestyle Changes
• Restrict sugared drinks and foods with added sugars.
• Limit refined carbohydrates such as foods made from flour
• Eat plenty of fruits, vegetables and seeds. Unprocessed vegetables, whole grains, nuts, other seeds and most fruits contain complex carbohydrates and fats that are not released rapidly into the bloodstream. These nutrient-rich foods do not cause high rises in blood sugar and insulin.
• Exercise. Resting muscles draw no sugar from the bloodstream, while contracting muscles draw sugar rapidly from the bloodstream and don’t even need insulin to do so. The more intensely you exercise, the less insulin is needed by muscles to draw sugar from the blood. This effect lasts for up to 17 hours after you finish exercising.
• Avoid being overweight. Your liver controls blood sugar levels. When blood sugar levels rise, insulin drives sugar from the bloodstream into the liver. However, the more fat you have stored in your liver, the harder it is for sugar to enter liver cells in response to insulin. A fatty liver will raise blood sugar levels even higher by releasing stored sugar from its cells into the bloodstream.
Definition of Sugar-Added Foods and Drinks
Added sugars are those put in food during processing or food preparation:
• packaged table sugar and all other high-calorie sweeteners
• all sugars in liquid form such as sugar in fruit juice, syrups, honey, vegetable juice, purees, pastes and similar products in which the cellular structure of the food has been broken down
• Other refined carbohydrates such as ground-up grains are similar to “added sugars” because grinding breaks up the seed capsules of whole grains to markedly raise blood sugar levels in foods made with flour (bread, pasta, pretzels, bagels, cookies, crackers and many dry breakfast cereals). A person who is insulin resistant should try to limit all sources of refined carbohydrates, not just added sugars.
• Sugars in dairy products or in fruits or vegetables are not considered “added sugars”.
Dr. Gabe Mirkin is a Villager. Learn more at www.drmirkin.com