Type 2 diabetes (T2D) is one of the most common metabolic diseases and, due to the associated micro- and macrovascular complications, one of the main causes of morbidity and mortality. The number of people with T2D is expected to increase dramatically over the next decade.
Overweight and obesity combined with excessive energy intake, Western dietary habits and low levels of physical activity are the main reasons for the increase in the prevalence of T2D. As a result of this negative development, global and regional diabetes-related healthcare expenditures are expected to increase significantly.
Observational results suggest that whole grain foods (WGFs) are beneficial for T2D. This finding was also supported by a study that emphasized consumption of WGFs as a means of increasing fiber in the diet.
In addition, high-fiber foods can have important beneficial effects, including glucose and metabolic control, as well as many other conditions. Thus, whole grain diets can have significant health and economic implications in terms of preventing T2D in the population.
WGFs are widely recognized as healthy foods due to their high fiber content, antioxidants, and phytochemicals. Human trials have shown the potential of a diet enriched with WGFs to reduce fat mass, increase metabolic rate, promote negative energy balance, increase insulin sensitivity, improve lipid profile, and reduce systemic inflammation. Epidemiological studies have shown an inverse association between consumption of WGFs and the risk of developing several serious chronic diseases alongside T2D: cardiovascular disease, obesity and some cancers.
Most of these observational studies to date have characterized the intake of WGFs as the sum of the WGF ingredients from all grain-containing foods, which may contain varying amounts of WGFs and refined grains. Despite similar proportions of bran and germ (about 13% and 2%, respectively), individual WGF foods typically contain different amounts of fiber, antioxidants, magnesium, and phytochemicals, resulting in different cardiovascular effects of different WGF types can health.
Higher consumption of total WGFs and several commonly consumed WGFs foods, including breakfast cereals, oatmeal, dark bread, brown rice, added bran, and wheat germ, were significantly associated with a lower risk of these disorders.
According to a Harvard School of Public Health study involving more than 118,000 people, consuming WGFs can also reduce the risk of all-cause mortality by up to 9%. The risk of death from cardiovascular disease fell even further, by as much as 15%. These researchers found that for each serving of whole grains, the risk of all-cause death decreased by 5% and cardiovascular disease-related deaths by 9%.
In another finding, bran intake was associated with up to a 6% lower risk of all-cause death and up to a 20% lower risk of death from cardiovascular disease-related WGFs. Switching from one serving of refined grains per day to one serving of WGF was associated with an 8% reduced risk of cardiovascular disease-related mortality. Switching from one serving of red meat per day to one serving of whole grains was associated with a 20% reduced risk of death from cardiovascular disease.