Most people know that eating white bread is less healthful than eating wholemeal bread because refining the flour from which white bread is made reduces its nutritional content. But what many people do not know is that white bread may contain toxic residues of the bleaching chemicals used to make it look so brightly white.
There are three basic types of products made by baking grains: cakes, pastries and breads.
For a type 2 diabetic all cakes and pastries are off the menu, simply because they are full of fat and are usually well-doused with sugar. Bread however is different. Most types of bread can be eaten by type 2 diabetics.
Bread is made with dough, a paste of flour and water. It may contain additional ingredients, such as salt or butter, to improve taste. The dough is usually leavened and allowed to rise, before being baked.
Unlike frying, baking does not require fat during cooking, which should make food prepared in this way attractive to type 2 diabetics―the problem lies in the ingredients you get in baked products and the type of flour used.
There are essentially two kinds of flour: wholemeal flour and refined flour. Some baked breads, such as wheat germ bread, whole-grain bread and whole-grain bread, are made from a mix of wholemeal and refined flours.
Wholemeal and refined flour
Flour is made by milling cereal grains into tiny pieces. Grains consist of three main parts, the endosperm, germ, and bran.
Endosperm is the main tissue inside the seeds. It provides us with nutrition in the form of starch, protein and oils.
The germ is the embryo, the reproductive part that germinates and grows into a plant. It is surrounded by the endosperm. The germ contains several essential nutrients, though these vary depending on the type of grain.
Wheat germ, for example, is a concentrated source of vitamin E, folate, phosphorus, thiamine, zinc and magnesium, essential fatty acids and fatty alcohols.
Bran is the hard outer layer of grain. It is rich in dietary fibre and essential fatty acids and contains starch (the most common carbohydrate in our diets), protein, vitamins and minerals.
The husk is the tough protective coating that surrounds grains. It needs to be removed before the grain can be eaten. This is done by threshing (beating) and winnowing (blowing away the broken off bits of husk).
Groats are the grains after threshing. Though the husk has gone groats still include the bran and the germ. Groats are nutritious but hard to chew so they have to be prepared by soaking and cooking.
Whole grains are cereal grains in their natural state, ie, as well as the endosperm, they also contain the bran and germ. As a general rule for type 2 diabetics, they fall into the eat-all-you-want category of foods.
Refined grains are groats from which the bran and germ have been removed by milling (grinding and sifting). Refining causes the grains to lose much of their vitamins and minerals.
The problem with refined grains
The refined flour from which white bread is made lacks the high levels of vitamins (especially B and E vitamins) and minerals found in wholegrain bread.
As regards B vitamins, 80% of thiamine, 60% of riboflavin and 75% of niacin are lost during refining. In addition, almost all the vitamin E is lost when the wheat germ and bran are removed.
The effect of refining on the mineral content of grains used for making bread is just as devastating.
During refining, about 50% of all calcium is lost. Other losses include 70% of phosphorus, 80% of iron, 75% of manganese, 50% of potassium, 65% of copper, and nearly all magnesium.
Refining also tends to destroy the proteins in the grains, as well as half the unsaturated fatty acids.
The upshot is that refined flour contains only poor quality protein and fattening starch and very little vitamins and minerals.
Sometimes thiamine, riboflavin, niacin, and iron may be added back later during processing. But, as the added nutrients represent a small fraction of the nutrients removed, refined grains are nutritionally much inferior to whole grains.
Removing the fibre and grinding the grains finely also increases the glycemic index value, ie glucose from refined grains is digested quicker by the body than glucose from whole grains.
This means that the spike in blood sugar you experience after eating refined grains is higher than it would be from eating wholemeal grains.
Benefits of whole grains
Eating whole grains is very healthful.
Though whole grains are loaded with carbohydrates, in countries where whole-grains are staples, diabetes is much less common than in North America and Europe―mainly due to the high fibre content in the bran of the whole grains, which slows the release of glucose.
Whole grains are great for our health in many other ways, thanks to their high levels of vitamins and minerals. Most whole grains, including brown rice and oats, are particularly rich in B vitamins.
Whole grains also have plenty of protein, up to 10 grams in a 1/2-cup serving. One of these proteins is gluten.
Gluten makes dough elastic, which helps it to rise and keep its shape. It constitutes about 80% of the protein in wheat seed, which is one reason why wheat is popular for bread-making. It is also found in barley and rye.
Thus it goes without saying that as a type 2 diabetic you should opt for porridge, cereals or bread made from whole grains rather than refined grains.
The problem with white bread
White bread is made from refined grain, usually wheat. It suffers from all the deficiencies associated with refined grains mentioned above. But white bread may also contain toxins because of the way it is bleached to produce its bright white colour.
The flour used to make white bread is chemically bleached, just like you bleach your clothes in the washing machine. Thus, when you are eating white bread, you are also eating the residual chemicals from the bleaching process.
Flour mills use different chemical bleaches, including chlorine, oxides and peroxides. Many of these chemicals destroy the vital wheat germ oil found even in the refined grains.
Some of these bleaching agents combine with proteins in the flour to produce alloxan, a chemical which has been shown in laboratory tests to destroy the beta cells of the pancreas. Beta cells are the cells that produce insulin.
Researchers have known of the connection between alloxan and diabetes for years. In fact, scientists studying diabetes often use the chemical to induce diabetes in laboratory rats.
That alloxan also destroys the beta cells of the pancreas in humans has not been proved. Even so, I would bet that alloxan can produce a version of type 2 diabetes in humans that is very similar to type 1 diabetes, which is a major reason why I avoid white bread like the plague.
The problems with white bread―made from nutritionally inferior refined flour which has been bleached―are becoming more widely known, and governments are beginning to encourage people to switch to eating wholemeal bread.
In Switzerland, for example, the sale of white bread is taxed. These tax revenues are used to subsidise the price of whole wheat bread and so encourage a switch to the healthier food.
Avoiding white bread would seem to be a smart thing to do.
You should also avoid brown bread, which is usually merely white bread to which a brown dye (usually caramel-based) has been added. Instead eat whole wheat, rye and grain breads made with wholemeal flour.