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Vitamins and Minerals

Calcium and Bone Health

Flour, particularly white flour, is rich in calcium, essential for strong, healthy bones and teeth. Six slices of white bread every day will provide around 20% of the recommended daily calcium intake. Bread is one of the best sources of calcium in our diet.

Calcium, the most abundant mineral in the body, is vital to the structural integrity of the bones and teeth. It also has a role in metabolic processes within the body. A lack of dietary calcium can lead to osteoporosis in which the bones become porous. Osteoporosis usually affects the whole skeleton, but it is most commonly causes breaks (fractures) to hones in the wrist, spine and hip. After the age of 35 years bone loss can increase as part of the natural aging process. It is extremely important that women at risk eat a calcium rich diet, take plenty of exercise and also make sure they are eating enough vitamin D (assists in the absorption of calcium into the bone).

The fortification of flour contributes to 14% of the total calcium intake and in the absence of this fortification it would be assumed that these intakes would fall below the recommended nutrient intake (RNI). The current RNI for calcium is 600mg a day for children and 1000mg a day for an adult.

Top calcium providers Amount of calcium in mg / per 100g of food
White bread 100mg
Brown bread 100mg
Wholemeal bread 100mg
Semi-skimmed milk 110mg
Cheddar cheese 720mg
Fruit yoghurt 160mg
Tinned salmon 91mg
Spinach 170mg
Kidney beans 71mg

Iron Status and Bread Consumption

Flour is one of the main sources of iron in the diet, which is an important mineral, essential for healthy blood cells and good circulation. Bread is an excellent source of iron. The major source of iron in the UK is from cereals including wheat flour and other cereal based products which together provide almost 50% of the daily iron intake. Intakes from iron have been declining for some time and there is particular concern that nearly 25% of women have dietary intakes below the Reference Nutrient Intake (RNI). The clinical affects of iron deficiency include general lethargy and anaemia and if untreated can result in severe long-term effects on mental and physical status and development. The current RNI for iron is 14.8 mg/day for women and around 10 mg/day for men.

Top iron providers Amount of iron in mg / per 100g of food
White bread 1.6 mg
Brown bread 3.2 mg
Wholemeal bread 3.5 mg
Peanut butter 2.0 mg
Dried apricots 3.4 mg
Broccoli
1.0 mg
Watercress
2.2 mg
Spinach 2.1 mg
Kidney beans 6.4 mg

B Vitamins

B vitamins thiamin and niacin help the body release energy from carbohydrate and help ensure the skin, eyes and nervous system remain healthy. Over a third of our daily requirement of thiamin comes from cereals and flour-based foods such as bread. Bread is also a good source of niacin, another B vitamin.

Folic Acid

Folic acid is present in wholemeal flour and added at higher levels to some breads. More general fortification in other flour is presently under consultation by an expert committee advising the Department of Health. Folic acid helps protect against neural tube defect in unborn babies and is an essential nutrient for pregnant mothers.
 

Selenium

Selenium is a trace element found widely in the environment. According to the Food Standards Agency (FSA) good sources include brazil nuts, bread, fish, meat and eggs. Selenium is present in fish (0.32mg/kg), offal (0.42mg/kg), brazil nuts (0.25mg/kg), eggs (0.16mg/kg), bread (0.053mg/kg) and other cereals (0.02mg/kg). The UK reference nutrient intake (RNI) for selenium is 0.075mg a day for men and 0.06mg a day for women (COMA values). You should be able to get all the selenium you need from your daily diet.

Selenium is an essential trace element, which is necessary for the functioning of the enzyme glutathione peroxidase, which protects against intracellular oxidative damage. In essence selenium functions as an anti-oxidant and can help protect the body from oxidative damage caused by stress, pollution and aging. Selenium has been claimed to reduce the incidence of a range of cancers, although the COMA report on Nutritional Aspects the Development of Cancers (1998) considered there to insufficient evidence for such a link. Research in this area continues.

The selenium concentration of plants is determined by the content and availability of the element in the soil in which they are grown. The selenium content of plant foods therefore varies from country to country.

Concerns have been raised that selenium intakes in the UK are falling. In previous years the UK milling industry used more wheat sourced from North America. North American wheat contains slightly higher levels of selenium than UK wheat. However UK wheat still contains more selenium than European grown wheat. Since the UK now uses mostly homegrown wheat - this is reflected by slightly lower levels of selenium than US wheat. The trend towards using UK rather than North American wheat coupled with the fact that there has been a decline in the consumption of cereals and wheat based foods such as bread (both good sources of dietary selenium) would result in slightly lower intakes of selenium in the UK.

Additional Nutrients

Fibre - wheat is an excellent source of fibre and wholemeal flour, which contains the whole grain including the bran and germ. Brown and white flour also contain fibre. For a healthy, balanced digestive system it is important that we eat enough fibre. All bread contains a significant amount of dietary fibre, although wholemeal bread contains three times as much as white bread.

Protein - flour is a good source of protein and is low fat, unlike some sources of animal proteins. Protein is essential for growth, maintenance and repair of the body.

Carbohydrates - the majority of carbohydrates in flour are complex carbohydrates that we all need to give us energy. We need to eat more complex carbohydrate - rich foods to replace some of the fat in our diets, for example nutritionists recommend we eat six slices of bread a day. According to the British Nutrition Foundation's Balance of Good Health, we should be eating 50% of our energy intake as carbohydrates.
 

Fortification

Flour is a natural and wholesome food.  By law, white and brown flour is fortified with calcium, iron, thiamin and niacin (see table below). Because it is made from the whole wheat grain, wholemeal flour already contains these vitamins and minerals, although white and brown flour contain more calcium because of fortification.
Calcium carbonate (E170) is added to all brown and white flour products in the UK and has been a legal requirement for almost 5 years. This is carried out to ensure that vulnerable groups receive enough calcium in their diet. On average 20% of the UK dietary calcium intake is accounted for via bread and flour products. Other legally required additives in bread include iron and B-Vitamins.

The following table shows the nutritional value of an average selection of flours:

g/100g except where stated Strong White Plain White Brown Wholemeal
 Extraction Rate % (approx) 75 75 85 100
Protein % variable depending on whether strong or weak flour 11.5 9.4 12.6 12.7
Fat 1.4 1.4 1.8 2.2
Carbohydrates 75.3 77.7 68.5 63.9
Fibre (englyst) 3.1 3.1 6.4 9.0
Calories (kcal) 341 341 323 310
Iron mg/100g 2.1 2.0 3.2 3.9
Thiamin mg/100g 0.32 0.32 0.39 0.47
Niacin mg/100g 2.0 1.7 4.0 5.7

McCance & Widdowson (6th Edition)

The nutritional composition of white, brown and wholemeal bread is compared in the table below:

  White Brown Wholemeal
Carbohydrate % 49.3 44.3 41.6
(of which sugars) % 2.6 3.0 1.8
Protein % 8.4 8.5 9.2
Fat % 1.9 2.0 2.5
Dietary Fibre % 2.3 4.7 7.1
Calcium mg/kg 1100 1000 540
Iron mg/kg 16 22 27
Thiamin mg/kg 2.1 2.7 3.4

(Source: MAFF)

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