Diabetes damages every part of the body, from the brain to the feet. High blood sugar, the hallmark of diabetes, wreaks havoc on blood vessels. It makes sense that keeping blood sugar under control should prevent diabetes-related damage — but how low to push blood sugar is an open question. A study published in The New England Journal of Medicine (NEJM) provides reassuring evidence that so-called tight blood sugar control is good for the heart and circulatory system. A 10-year follow-up of the Veterans Affairs Diabetes Trial showed that participants who aimed for tight blood sugar control had lower blood sugar and fewer heart attacks and strokes than participants whose blood sugar was allowed to float a bit higher. Although tight blood sugar control can help prevent diabetes-related damage, it can have drawbacks such as bouts of low blood sugar (hypoglycemia), which can be dangerous. Current guidelines from the American Diabetes Association recommend tight blood sugar control, but also recognize there’s no one-size-fits-all rule.