Bread is highly nutritious and is eaten with most meals in many cultures. But some types of bread are not suitable for diabetics. Here’s the low-down on what breads diabetics should and should not eat.
To beat your diabetes you need to eat food that is low in sugar, low in fat, low in salt, high in fibre and has low GI values, ie it releases glucose into your bloodstream relatively slowly. Some kinds of bread fit this bill; others do not.
Bread is made from flour, ie grain that has been ground into powder. Common wheat is usually used because its flour has high levels of gluten, which gives the dough sponginess and elasticity.
But bread is also made from other species of wheat (eg, durum and spelt) and other grains such as rye, barley, corn (maize) and oats. The non-wheat grains usually have wheat flour mixed into the flour.
The quality of bread depends largely on the protein content of the flour. The best breads use flour with 12 to 14% protein rather than all-purpose wheat flour which only contains 9 to 12% protein.
Whole grains or refined grains?
When cereal grains such as wheat are harvested they are surrounded by a tough protective coating called a husk.
Before you can eat the grains, the husk has to be removed. This is done by threshing (beating the grains) and winnowing (blowing away the chaff, ie the broken off bits of husk).
The grain without its husk is called a groat. It consists of three main parts: the endosperm, germ and bran.
The endosperm is the main tissue inside the grain and provides 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. 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, protein, vitamins and minerals.
As you can see, the germ and bran contain lots of healthy stuff that is not found in the endosperm.
Whole grains are cereal grains in their natural state, ie they contain all three main parts, endosperm, bran and germ.
Refined grains are groats from which the bran and germ have been removed by grinding and sifting.
Refining causes the grains to lose some of their nutritional value. Sometimes nutrients such as vitamins are added back. But, as these represent a small fraction of the nutrients removed, refined grains are nutritionally inferior to whole grains.
Removing the bran and grinding the grains into a fine powder increases the glycemic index value (GI) of the grain, ie you digest glucose from refined grains quicker than glucose from whole grains which, as a diabetic, is not what you want.
It is the high fibre 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 are particularly rich in B vitamins. Whole grains also have plenty of protein.
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.
Bread is made by mixing up dough, a paste of flour and water (or other liquid). The dough is usually leavened (see below), allowed to rise, and then cooked.
Breads may also contain extra ingredients, such as salt or butter, to improve taste. Improvers are additives used to quicken the rising time, increase volume and enhance texture.
Salt is one of the most common improvers; it is used to enhance flavour and the crumb (the inside of the bread) by strengthening the gluten. Improvers may include ascorbic acid and ammonium chloride.
Certain fats such as butter, vegetable oils, lard and egg fat are solid at room temperature. These shortenings, as they are known, are used to keep the structure together during the development of the gluten. A fat content of about 3% by weight is considered best to enhance leavening.
Fats also help tenderise bread and preserve its freshness.
Cooking is usually by baking in an oven. But bread can be made by frying in oil (eg, Indian puri), baking on a dry frying pan (eg, Mexican tortillas) and by steaming (eg, Chinese mantou).
As you can see bread can contain ingredients that those of us who have type 2 diabetes need to avoid … salt and fats. It pays to check the labels.
Leavening is the adding of gas to the dough, creating bubbles that make it swell up. This makes the bread lighter and easier to chew.
When flour and water are combined to make dough, the starch in the flour mixes with the water to form a matrix. When this mixture is leavened (ie gas is added), the dough ‘rises’. Then, when it sets, the bubbles remain trapped in the dough.
There are several ways dough can be leavened. However most types of bread are leavened using biological agents containing micro-organisms that release carbon dioxide as part of their life-cycle. These are either yeasts or sourdough starters.
Yeast ferments some of the carbohydrates in the flour. This produces bubbles of carbon dioxide, which makes the dough rise.
This kind of leavening requires proofing, ie a resting time to allow the yeast time to reproduce and consume carbohydrates. Breads leavened with yeast have a distinctive flavour.
A sourdough starter is a paste of flour and water containing yeast and lactobacilli which has been obtained from a previous batch of dough. It works in the same way as yeast, by creating bubbles, but it requires much more proofing time than yeast.
Sourdough bread has a sour, tangy taste. It is used for rye-based breads where yeast is not really effective in leavening the dough.
Chemical leaveners are chemical mixtures that release carbon dioxide or other gases when they react to moisture and heat. The most popular is baking powder, a mixture of a carbonate or bicarbonate (usually sodium bicarbonate) and one or more acid salts.
Baking powder works by releasing carbon dioxide gas into the dough when it gets wet, creating bubbles that expand the wet mixture. It is used instead of yeast for breads where the flavours of fermentation would be undesirable or where the dough lacks the elastic structure needed to hold gas bubbles for more than a few minutes.
Because carbon dioxide is released at a faster rate through the acid-base reaction than through fermentation, breads made by chemical leavening are called quick breads. Examples of quick breads include Irish soda bread, banana bread, pancakes, carrot cake and muffins.
The big question for diabetics, of course, is whether the rising method has any effect on the glycemic index (GI) value of the bread.
The intuitive answer is that it must worsen the GI value because it introduces air into the matrix. But, according to researchers in New Zealand, the leavening agents used in making bread do not have any impact on the GI of the bread.
Types of bread
There are hundreds of different breads in the world. Here are a few of the most common. Notice the subtle differences which may or may not be designed to confuse the consumer.
White bread is made from refined flour, ie grain from which the bran and germ have been removed so that it only contains the endosperm (the central core of the grain). By contrast, wholemeal bread is made from the whole of the wheat grain (endosperm, bran, and germ), ie from unrefined flour.
Brown bread is not the same as wholemeal bread. In fact, brown bread is nothing more than white bread to which a (usually caramel-based) colouring has been added to make it brown; it may also have up to 10% added bran.
Whole-grain bread is white bread to which whole grains have been added to increase its fibre content; eg, ‘60% whole-grain bread’. It is not the same as wholemeal bread which is made from 100% whole grains.
Granary bread is made from flaked wheat grains and white or brown flour. Wheat germ bread is any kind of bread to which wheat germ has been added for flavouring.
Rye bread is bread made with rye rather than wheat. It has more fibre than most other breads, a darker colour and a stronger flavour. Crisp bread is a flat and dry type of bread or cracker, made mostly of rye flour.
Flatbreads are made from unleavened dough of flour, water and salt, though a few are made with yeast. Flatbreads are especially popular in the Middle East and the Indian subcontinent.
Roti is the unleavened whole-wheat bread of India; chapatti is the large version of roti; naan is the leavened equivalent.
Bread for diabetics
To beat your diabetes you need to ensure that the food you eat is low in sugar, low in fat, low in salt, high in fibre, and has low GI values.
This is a fairly easy thing to do … all you have to do is read the labels to see the amount of sugar, fat, salt and fibre in a particular loaf of bread.
The problem with the labels for breads is that they do not normally indicate the glycemic index (GI) value of the bread.
Bread and the glycemic index
The glycemic index rates foods on a scale of 1 to 100 based on how the foods affect your blood glucose levels. A rating of less than 55 is considered low, 56 to 69 medium, and 70 plus high.
Bread ranges from 34 to 73 or more depending on the kind of grains used to make it.
Bread with a low rating will be broken down more slowly in your gut giving you a steady increase in your blood sugar level.
Bread with a GI value of 70 or more will cause your blood glucose to spike, ie to surge and then drop suddenly.
Labels for bread do not usually show whether bread has a low GI value. However you can usually estimate whether the GI value is low or not by checking the ingredients. These are usually listed in descending order by weight.
So, if the first ingredient is whole-wheat flour, it is likely that the bread has a lower GI value than bread for which refined flour is listed as the first ingredient.
Sometimes the percentage by weight of each main ingredient is shown in brackets in the list, and this information can be used to estimate whether the bread has a low GI value.
Breads diabetics should avoid
White rolls have a GI value of about 73, white loaf about 71, and baguettes a rating of 95 which is extremely high. Indeed, to control your diabetes, you need to avoid all white bread and also brown bread as it is essentially only coloured white bread.
Other breads you need to avoid are quick breads, such as Irish soda bread, unless they are made from wholemeal flour, breads with a high salt content, and malted breads which usually have a high sugar content.
You also need to avoid breads made with shortening unless the fat content is less than 3% by weight, as well as all fried breads such as Indian puri.
This still leaves you with plenty of breads you can eat and still beat your diabetes.
Breads diabetics can eat
Whole-grain breads usually have low GI values (less than 56). Regular whole-grain bread has a GI value of about 51, while the rating for pumpernickel is about 50.
Barley bread (if you can find it) is very dense and has a GI value of about 34, while wheat tortillas have a rating of about 30.
Thus as a diabetic you can eat most wholemeal breads, rye breads and crisp breads made from rye. You can also eat unleavened flatbreads, such as whole-wheat Indian breads like roti and chapatti, though you need to check the salt and fat content.
Plenty of breads can be classified as semi-wholemeal, ie bread made form a mix of whole grains and refined grains. It is noticeable that as the ratio of whole grains in the flour rises, the GI value drops.
For example, a 50:50 mix of wholemeal and refined flour usually has a GI value of at least 58, while 100% wholemeal bread has an average GI value of 51.
Thus you need to be cautious when eating whole-grain bread (white bread with added whole grains) and granary bread.
You should only eat small amounts of white pitta bread (GI value about 57). Whole-grain pitta, however, has a slightly lower GI value due to the phytates they contain, which slow the rate of digestion.
So there you have it. When deciding which bread to choose to beat your diabetes, you should favour bread made from 100% wholemeal flour which has a low salt (sodium) content, low fat (maximum 3% by weight) and does not contain added sugar.
You’ll find all this information, as well as the amount of fibre the bread contains, on the label.