It’s well-established that diet plays a significant role in the risk of developing type 2 diabetes.
An unhealthy eating pattern can lead to type 2 diabetes by causing changes in blood sugar levels, insulin sensitivity, inflammation, liver fat or the gut microbiome. It can also raise diabetes risk by promoting weight gain.
It’s unclear, though, how specific dietary components contribute to the global risk of type 2 diabetes. Until now.
According to researchers from Tufts University in Boston, Mass., too many refined carbohydrates and processed meats are leading dietary drivers of new diabetes diagnoses worldwide.
Global rise in type 2 diabetes
The exponential rise in type 2 diabetes is a global phenomenon. According to the study authors, no country has experienced a decline in the chronic disease over the last 40 years.
In type 2 diabetes, cells in the body become resistant to the action of insulin, the hormone that clears glucose (sugar) from the bloodstream. As a result, blood glucose levels remain higher than what’s considered normal.
Type 2 diabetes is the leading cause of illness and death globally. It increases the risk of heart disease, stroke, kidney disease, blindness, nerve damage, Alzheimer’s disease and certain cancers.
It’s estimated that 9 per cent of Canadians have a diagnosis of diabetes. Type 2 diabetes accounts for 90 per cent of these cases.
The latest findings
For the study, published this April in the journal Nature Medicine, the researchers set out to assess the impact of 11 dietary factors – separately and combined – on the risk of developing type 2 diabetes among adults globally.
To do so, they developed a research model using global dietary data and new diabetes diagnoses from 1990 and 2018. Of the 184 countries included in the study, all experienced an increase in type 2 diabetes.
The researchers estimated that a suboptimal intake of 11 dietary factors contributed to 70 per cent of new type 2 diabetes diagnoses worldwide in 2018.
These dietary factors included whole grains, whole fruit, nuts and seeds, yogurt, non-starchy vegetables, refined grains (wheat and rice), potatoes, processed meats, unprocessed red meat, sugar-sweetened beverages and fruit juice.
Three dietary components made an outsized contribution to fuelling the rise in type 2 diabetes: eating too few whole grains, too many refined grains and too many processed meats.
The findings suggested that poor carbohydrate quality was the leading driver of global type 2 diabetes cases in 2018.
The researchers concluded the findings should inform “dietary priorities and clinical and public health planning to improve diet quality and reduce type 2 diabetes globally.”
This study does not prove cause and effect. Rather the research generated estimates of diabetes risk from certain dietary factors.
Swap refined grains for whole grains
Numerous large studies have associated higher daily whole grain intakes with a significantly lower risk of type 2 diabetes. Whole grains contain fibre (e.g., bran), which slows down whole grain digestion and leads to slower and lower rises in blood sugar compared to refined grains.
The fibre, vitamins, minerals and protective phytochemicals in whole grains are also thought to improve how the body uses insulin. As well, whole grains are good sources of magnesium, a mineral that’s needed to regulate blood sugar.
When whole grains are processed into refined flour or white rice, for example, their bran and germ layers are removed resulting in a loss of most of the fibre as well as a significant amount of many nutrients.
An optimal daily intake of whole grains is considered at least three servings, or 90 grams. One serving is equivalent to one slice of 100 per cent whole grain bread, one half-cup of cooked whole grain or one cup of whole grain cold breakfast cereal.
Read labels on packages of whole grain breads, crackers and breakfast cereals. If you don’t see “100 per cent whole grain,” scan the ingredient list to make sure the product doesn’t contain refined grains.
Batch cook whole grains such as brown rice, red rice, black rice, farro, wheat berries, spelt berries, de-hulled barley and bulgur. They’ll keep for three to four days in the fridge or two months in the freezer.
Oats, quinoa, rye berries, millet, teff, sorghum, buckwheat and amaranth are other whole grains to include in your diet.
Toss cooked whole grains to salads, stir into soups, stews and chili, or use them to make grain bowls. Instead of refined bread crumbs, add cooked whole grains to ground turkey to make burgers. Use whole grain noodles for pasta dishes.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD