White Bread, Starch Increases Diabetes Risk

Thu Nov 4, 1:24 PM ET

By Alison McCook

NEW YORK (Reuters Health) - Fans of white bread, hear this: it increases your risk of type 2 diabetes, the most common form of the illness, new research shows.

Other foods that appeared to increase diabetes risk include starchy foods and foods that like white bread encourage a spike in blood sugar, such as crackers, cookies, and cakes.

So people looking to minimize their risk of diabetes should opt for foods that don't cause blood sugar roller coasters, lead author Allison Hodge of The Cancer Council in Victoria, Australia, told Reuters Health. These foods include vegetables, fruit, and multi-grain breads, she said.

Hodge explained that she and her colleagues measured a food's effect on blood sugar levels according to its glycemic index (GI), a term that only applies to carbohydrates. High-GI foods tend to cause a big increase in blood sugar, while low-GI foods have a weaker effect, she said.

To investigate how the glycemic index can influence the risk of type 2 diabetes, Hodge and her colleagues followed 36,787 diabetes-free people between the ages of 40 and 69 for 4 years, noting what they ate and whether they developed diabetes.

Almost 400 people developed diabetes over the 4-year period, the authors report in the journal Diabetes Care.

Hodge and her team found that people who ate the most white bread -- half of whom said they had it at least 17 times each week -- were more than 30 percent more likely to develop type 2 diabetes.

Starch lovers and people who consistently opted for high-GI foods also showed a significantly higher risk of diabetes over the four-year period.

Hodge explained that high-GI foods may increase diabetes risk by causing weight gain, which increases the risk of type 2 diabetes.

Also, "A high GI diet may also require the pancreas to produce a lot of insulin to deal with the high blood glucose levels, and this may exhaust the cells that produce insulin, and contribute to development of type 2 diabetes," Hodge added.

In addition, the researchers found that people who ate large amounts of carbohydrates, sugars and magnesium appeared to be somewhat protected from type 2 diabetes.

Although the reasons behind this association are somewhat unclear, Hodge suggested that diets high in carbohydrates may also be low in fat, and protect the functioning of insulin.

Sugars that were linked to a lower diabetes risk included those found in fruit, she said, and people should stick to carbohydrates and sugars found in low-GI foods, such as fruits, vegetables and whole grains, which also tend to be high in magnesium.

Other relatively low-GI foods include certain breakfast cereals, pasta, and basmati rice, which has a lower GI than brown or white rice, she said.

But moderation is key, even with healthy foods, she said. "As with any food, if eaten to excess, overweight and obesity will ensue, and increase the risk of type 2 diabetes more than any change in food choices can reduce it."

SOURCE: Diabetes Care, November 2004.