For people with diabetes, it’s practically inevitable that at some point, you’ll meet someone with the misguided perception that the condition is caused by eating too much sugar — or that avoiding sugar is all it takes to manage diabetes.
Of course, the reality of living with diabetes is that most forms of carbohydrate can have a significant impact on blood glucose levels. While everyone reacts a bit differently to different foods, sugar is often no worse for blood glucose levels than starches and other easily digested carbs.
So does this means that sugar shouldn’t be singled out, and instead treated like every other type of carbohydrate? Not so fast, says a recent article on the impact of sugar intake on heart health.
High vs. low sugar intake
The article, published in December 2017 in the journal Open Heart, is an editorial looking at the ways that added sugar in the diet contribute to a higher risk of heart disease. The authors cite a 2014 study showing that, compared with those eating a diet containing less than 10% added sugar, U.S. adults who ate a diet consisting of at least 25% added sugar were 2.75 times as likely to die of heart disease. Why, they ask, does sugar have this effect?
The answer, the authors suggest, lies in how sugar affects insulin resistance and insulin levels. They note that nearly three out of four people who experience a heart attack are found to have had abnormal glucose tolerance at that time, which may be brought on by the acute stress of the situation. But even six months after their heart attack, 43% of these people still show abnormal glucose tolerance — about three times the level of people with otherwise similar characteristics who haven’t had a heart attack.
And sugar does seem to have a large effect on insulin resistance and glucose tolerance. Part of this effect may be due to the tendency of sugar — in its sucrose and fructose forms — to promote the growth of fat tissue, which is often more resistant to the effects of insulin than other types of tissue in the body. But even without any impact on body fat, consuming a high-sugar diet may directly reduce the body’s sensitivity to insulin.
Association or cause?
Of course, it’s possible that even if abnormal glucose tolerance is associated with a higher heart risk, it may not necessarily be the cause of this risk — both could, in fact, be the result of something else. And it’s well known that people with insulin resistance are more likely to carry other risk factors for heart disease, like higher LDL (“bad”) cholesterol and triglyceride levels.
But certain facts, the authors write, suggest that glucose metabolism is central to the heart disease process. One is that during a heart attack, the heart’s main source of energy switches from fatty acids to glucose — which may explain why heart attacks are more likely to be deadly in people with higher insulin resistance, since their bodies can’t give the heart the energy it needs quickly enough.
Another relevant fact may be that people without diabetes who have vascular disease are more likely to have increased insulin levels. So even if insulin resistance isn’t great enough to raise blood glucose levels, it may have an impact on heart disease risk.
Reversing heart risk
The good news, the authors write, is that cutting back on sugar can substantially reduce your risk of heart disease. This has been shown in short-term studies in which increasing sugar in the diet for just a few weeks leads to worsened heart disease in as many as one third of study participants, with the effects going away once sugar returns to its previous levels in the diet.
But the weight of evidence also suggests that over time, reducing sugar in your diet may help reverse even longstanding heart disease risk factors like insulin resistance, abnormal glucose tolerance, and even seemingly unrelated factors like triglyceride and HDL (“good”) cholesterol levels.
So even if your diabetes is under control, your heart may be a good reason to cut back on sugar in your diet.
Want to learn more about reducing heart disease risk? Read “Fight Off Heart Disease With These Five Heart-Healthy Foods,” then test your knowledge with our heart disease quiz.