There are differences between definitions of whole grain bread and whole wheat bread on the two sides of the Atlantic, although the basic difference is the same.
Whole grain bread is made with whole grain flour. This means that all the grain is retained, the bran which is the outer layer of the grain; the endosperm which is the middle layer of the grain and the germ which is the inner layer where the seeds begin to sprout. During the refining process no part of the wheat or other grain is lost. This type of bread is therefore the most nutritious.
Whole wheat bread in the US may have been refined almost as much as unbleached white flour. In other words, the bran and germ may have been lost. Whole wheat bread may be referred to in the UK as whole meal bread. In this case nothing has been removed during the milling process, and the same goes for the whole grain bread, which will be wheat, rye or pumpernickel bread in Europe. These breads are dense and full of fibre and nutrients. In North America, whole grain bread is usually whole wheat bread.
In North America the labeling is tricky to decipher on brown breads. For example, in Canada you need to look for whole wheat flour or wholegrain wheat flour as whole-wheat alone can mean that up to 70 percent of the wheat germ has been removed. As the germ contains the phytonutrients with the most antioxidant properties (antioxidants will combat the free radicals which damage healthy cells and may cause cancer), you are losing out on some health benefits if the germ is not in the bread.
If you see “enriched” or “bromated” on the bread label, it will not be wholegrain or whole wheat. If you see wheat flour on the label this does not indicate what type of bread it is, other than it came from wheat. You cannot tell from this if there is any germ left in the product. However if the label says whole wheat flour or wholegrain wheat flour, then this is what the product contains.
There is now the Whole Grain Stamp which can be found on some but not all breads. Look for the official symbol and the Whole Grain Stamp. The 100 % stamp indicates that there is a full serving or more of whole grain in each labeled serving of the bread. The basic whole grain stamp indicates that there is at least half a serving of whole grain in each serving as labeled.
Whole grain flour and whole grains in our diets have been linked by researchers to a reduction of cancers, notably colon cancer, as they are high in fibre content. These whole grains also help to reduce the risk of heart disease it is thought. Whole grain breads are good for people managing Type-2 diabetes with their diets, as they do not cause a significant spike in blood glucose levels. Whole grain breads are absorbed into our systems more easily than other heavily refined products. They also contain more dietary fibre than other breads, which means that they help to prevent constipation which can cause piles and possibly contribute to colon cancer.
Whole grain breads contain the B-complex vitamins, B1, B2 and B3 as well as vitamin E and the minerals; iron, potassium, zinc and copper, along with other phytonutrients.
Read the packaging and list of ingredients carefully when looking for whole grain bread. If whole wheat flour is the first ingredient on the label, it is likely to be just that, with nothing removed. However there is no absolute guarantee of this. On the other hand, if it says 100% whole wheat then it will be.