Whole grains, cereals and cereal products
We have been consuming grain foods for at least the past 10,000 years. Grain foods, include cereals, are dietary staples for many cultures around the world. Cereals provide the average human with around one fifth of their daily nutrient requirements. Current research around the world is discovering the many health benefits that wholegrain cereal foods can offer, particularly in reducing the risk of diseases such as coronary heart disease, cancer and diabetes Grains include wheat, barley, oat, rye, corn, rice, triticale.
Wholegrains include wholemeal or wholegrain atta, breads, dark 'seedy' breads, wholegrain breakfast cereals, wheat germ, brown rice, puffed whole grains, bulgar, couscous, pop corn and oatmeal. Refined cereals include maida, cake, desserts, white bread, pasta, muffins, sweet or salty biscuits, refined grain breakfast cereals, white rice, pancakes, waffles and pizza.
Nutritional content of whole grain cereals
The kernels of grains (such as wheat, barley, oat, rye, corn, rice, triticale) consist of 3 major parts:
Bran- this is the outer layer of the grain (14-16% of wheat, 5-6% of corn)
Endosperm - this is the main part of the grain
Germ - this is the smallest part of the grain.
Wholegrains contain all three layers of the grain.
Whole grain cereals provide a rich source of many essential vitamins, minerals and phytochemicals. The typical cereal food is:
Low in saturated fat but is a source of polyunsatured fats, including omega 3 linolenic acid.
High in both soluble and insoluble fibre and resistant starch
An excellent source of carbohydrates
A significant source of protein
A good source of B-complex vitamins, including folate
A good source of many minerals - such as iron, magnesium, copper, phosphorus and zinc.
A good source of antioxidants, including vitamin E and selenium as well as phytochemicals including phytoestrogens, phytic acid, flavonoids and phytosterols (which can help lower blood cholesterol levels)
When grains are refined (for example to produce white flour), the bran and germ layers are generally removed, leaving only the endosperm. This 'refining' process can cause 66% loss of fibre, 92% loss of selenium, 62% loss of folate and up to 99.8% of phytochemicals from the grains. Some fibre, vitamins and minerals may be added back into refined cereal products (such as white bread) which compensates for losses due to refining, but its impossible to add the mix of phytochemicals that's lost in the processing.
Refined cereals, such as white flour, generally have a higher glycaemic index (GI) than their wholegrain counterparts. This means that consuming refined cereals causes a sharp rise in blood sugars, demanding a strong response from the pancreas. A diet full of high glycaemic index foods has been linked to the development of diabetes and heart disease. Studies have also found that people who eat large amounts of refined cereals do so at the expense of more nutritious foods like fruits and vegetables. This increases the risk of certain diseases, such as some types of cancer.