Can sugar worsen cholesterol?
Researchers have found a link between sugar and unhealthy levels of blood fats. “There’s an association between added sugar intake and what we call dyslipidemia -- higher triglycerides and lower HDL ("good") cholesterol, says Rachel K. Johnson, RD, MPH, PhD, a professor of nutrition at the University of Vermont and a spokeswoman for the American Heart Association (AHA).
In a study published in the Journal of the American Medical Association (JAMA), people who ate the largest amounts of added sugar had the highest blood triglyceride levels and the lowest HDL (good) cholesterol levels. That study also showed that eating lots of sugar more than tripled the odds of having low HDL cholesterol levels, a strong risk factor for heart disease.
In contrast, people who ate the least sugar had the lowest triglyceride levels and highest HDL levels, a protective factor against heart disease.
But "the study doesn’t prove that added sugars cause dyslipidemia,” says Johnson, who wasn't involved in the JAMA study.
Johnson says that to prove that sugar causes problems with blood fats, scientists would have to conduct a clinical trial in which some people ate a diet high in added sugar and others ate a diet low in added sugar. Then researchers would track their triglyceride and cholesterol levels. Such a study would be expensive and hard to carry out, she says.
However, Johnson points out that weight did not explain the JAMA findings. “Obesity is obviously related to dyslipidemia, but based on the JAMA paper, the added sugars had an independent effect, separate and distinct from the added sugars’ impact on weight," she says.
Does sugar cause diabetes?
"Eating sugar per se does not cause diabetes," Johnson says. But large, epidemiological research has shown an association between intake of sugar-sweetened beverages and diabetes, she says.
The real culprit may be obesity. "It may be because the sugar-sweetened beverages are associated with higher BMIs or associated with overweight and obesity, which we know is a risk factor for diabetes," Johnson says.
Is sugar affecting children's health?
Pediatricians are concerned that too much sugar is in their young patients' diets, Kavey says. But again, sugar by itself is not the problem, she says, but rather the excess pounds.