Hard wheat has a higher amount of protein (between 12 to 14%) but also has a larger amount of gluten; this type of wheat produces the flour used to make bread and pasta.
Soft wheat has a smaller amount of protein (less than 10%) and it also has less gluten; this type of wheat produces flour that is best used for bakery.
Now if we are talking about “whole cereals” such as wheat bran, we all know about the endless articles and studies about how they help us have a better digestion and avoid constipation, but wheat bran has been deeply investigated about its protective effect against colon cancer and breast cancer.
Wheat bran has significant beneficial effects on the human physiology.
Diverticulosis also known as “diverticular disease” is the condition of having diverticula in the colon, which are outpocketings of the colonic mucosa and submucosa through weaknesses of muscle layers in the colon wall. The objective of a treatment for this disease, when there are no complications, is to relieve the symptoms and prevent the apparition of complications. The best results have been achieved with unprocessed wheat bran added to food or the consumption of whole wheat bread and high fiber breakfast cereals.
Colon cancer is known to be the second cause of death by cancer in USA and it has been related to Risk Factors that could be controlled by diet. Since the cure is still not available, prevention is our most powerful tool to reduce the risk. Studies have concluded that the presence of fiber in the diet is essential in the prevention of colon cancer, but not all types of fiber have the same protective effect and wheat bran seems to be the one that shows a more development-inhibiting effect on colon cancer.
According to a study performed in 1991 (Rose, D.P., M. Goldman, J.M. Connolly and L.E. Strong), whole wheat of wheat bran (but not oatmeal bran or corn bran) reduces significantly the concentration of estrogen circulating in our blood stream, specifically serum levels of estrone and estradiol. Since this concentration is directly related to breast cancer it is believed that whole wheat has a positive effect on the prevention of breast cancer. Also, phytic acid is contained in wheat bran, and this acid is known by its anticarcinogen effects since it is a natural antioxidant, it has been suggested that phytic acid may reduce the size of mammary tumors especially if the diet also includes significant quantities of minerals such as calcium and iron.
Whole wheat is mostly composed of insoluble fiber; there are a couple of studies that suggest that the regular consumption of insoluble fiber is directly related to the reduction of the risk of acquiring type II diabetes and cardiovascular diseases.
Source: Functional Foods: Biochemical and Processing Aspects