A sugary diet may harm your heart

When it comes to carbohydrates and cardiovascular health, the evidence suggests that quality trumps quantity — that is, the type of carbohydrate-rich food you consume matters more than the amount. A new study suggests that's especially the case for sugar, one of the most abundant carbohydrates in the typical American diet.

Sugars occur naturally in many whole foods, including fruits, vegetables, dairy products, and grains. But the majority of sugar in our diets is added sugar, which comes mostly from high-fructose corn syrup or sucrose. Also known as table sugar, sucrose is extracted mainly from sugar cane and sugar beets.

Diets high in these processed sugars were linked to an increased risk of coronary artery disease, according to the study, which was published Sept. 1, 2023, in the American Journal of Clinical Nutrition. The findings were gleaned from dietary and health data on nearly 144,000 people participating in two long-running Harvard studies, the Nurses' Health Study and the Health Professionals Follow-up Study.

"However, naturally occurring sugars in fruits and vegetables were not associated with a higher risk of heart problems," says study co-author Dr. JoAnn Manson, chief of the Division of Preventive Medicine at Harvard-­affiliated Brigham and Women's Hospital.

In fact, eating more fruits and vegetables appears to lower the risk of heart disease. One likely reason: these foods are rich in fiber, which slows down digestion and the absorption of sugar into the bloodstream, lowering the risk of weight gain and diabetes. Fruits and veggies also contain minerals (especially potassium) and plant-based chemicals called polyphenols that keep blood vessels healthy.

The downsides of added sugars

In contrast, added sugars provide "empty" calories and can promote weight gain. Moreover, a steady stream of sugary drinks and foods can tax the body's blood sugar control system, setting the stage for diabetes. Both excess weight and diabetes raise the risk of heart disease. Too much added sugar in the diet also spurs the liver to pump out triglycerides and other fats (lipids) into the bloodstream. Higher blood lipids (especially harmful LDL cholesterol) contribute to cardiovascular risk.

How much added sugar is too much? The Dietary Guidelines for Americans recommend limiting added sugar to no more than 10% of your total daily calories. For a typical 2,000-calorie diet, that's 200 calories, or 50 grams of added sugar per day. But most Americans are way over that limit, with some consuming as much as 20% or even 30% of their total calories as added sugars, says Dr. Manson.

Sources of added sugars

According to the dietary guidelines, nearly 70% of added sugars come from these five types of food and drink:

• sweetened beverages such as colas, fruit juices, and sports drinks
• desserts and sweet snacks, including cookies, brownies, cakes, pies, ice cream and other frozen dairy desserts, and doughnuts.
• sugar-sweetened coffee and tea drinks, including canned and bottled products as well as those served up at coffee shops
• candy
• breakfast bars and cereals.

To get a sense of how much sugar you're consuming, check your food labels, Dr. Manson advises. FDA labeling regulations now require food manufacturers to list the amount of added sugar in grams per serving. Other common products that contain added sugars include yogurt, canned fruit, barbecue sauce, ketchup, salad dressings, marinades, salsa, and picante sauce. If you regularly have sweet items from restaurants, bakeries, or coffee shops, you'll need to request the information about added sugar, or it may be available online.

If you need to cut back, avoiding sugary drinks is often the easiest place to start. A 12-ounce regular soda contains about 40 grams of sugar. Fancy coffee drinks, which are often laden with flavored syrups and topped with sweetened whipped cream, often contain similar amounts. Instead, try sparkling water with a splash of fruit juice. "Don't worry about adding a teaspoon of sugar to your coffee or tea, since that's just a fraction of what store-bought sodas or other sugary drinks contain," says Dr. Manson.

And don't forget to eat more fruit! Enjoy a variety, since all fresh fruits are healthy. But try to include those that are especially rich in flavanols and other polyphenols, such as apples and pears, as well as strawberries, blueberries, raspberries, and blackberries.

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