Replacing that daily muffin with a handful or two of nuts may help people with diabetes better control their blood sugar and cholesterol levels, a new study suggests.

Researchers found that when people with type 2 diabetes replaced some of their usual carbohydrates with about a half-cup of mixed nuts each day, the study participants' blood sugar and "bad" cholesterol levels dipped slightly over three months.

In contrast, no such improvements were seen among people who swapped their normal carbs for a daily whole-wheat muffin.

The findings, published in the journal Diabetes Care, do not mean that nuts are the key to diabetes control, the authors say.

"We should be focusing on overall diet and lifestyle," says Cyril W.C. Kendall of the University of Toronto in Canada, one of the researchers on the study.

The point, he says, is that "nuts can be part of a healthy diet".

"They have a lot of fat, but we now realize that those fats are healthy ones," Kendall adds, referring to the unsaturated fats that have been linked to a lower risk of heart disease and other health benefits.

Still, nuts are high in calories, and people with diabetes should not simply add a handful to their usual diet, according to Kendall.

"They could use them instead to displace some of the less healthy snacks they usually have," he says.