Grains (Cereals)

Grains (Cereals)

• What are grains?
• Nutritional value of grains
  • Vitamins
  • Minerals
  • Protein
  • Energy
• What effect does processing have on grains?

• Can grains be bad for nutrition?
  • How are grains good for your health?
  • Summary

  protein, vitamins and minerals) are concentrated in the aleuronic layer, whilst the endosperm consists mainly of starch.

  With the advent of agriculture in the early history of human civilisation, grain consumption became prominent, especially in developing countries. Grains constitute a major source of energy in most households today, and occupy the base of food pyramids. Examples of grains are wheat, maize, rice, barley oats, millet and sorghum. 

  vitamins A, C and B12, they contain a range of micronutrients such as vitamin E, some of the B vitamins (for example B6), magnesium and zinc.  The bioavailability of the B-vitamins, however, appears to be low. For example, the bioavailability of B6 from grains tends to be low, whereas bioavailability of B6 from animal products is generally quite high.

  calcium from a wider variety of sources, such as in dairy and some vegetables.

  Ideally, calcium and phosphorus occur in the ratio of 1:1. However, grains have a low calcium/phosphorus ratio, which can negatively impact bone growth and metabolism. This is because consumption of an excess of dietary phosphorus when calcium intake is inadequate or low is reported to result in secondary hyperparathyroidism and progressive bone loss.

  The high phytate content of whole grain grains may reduce the availability of calcium for absorption because the phytate forms insoluble complexes with calcium. The combined effect of low calcium content, a low Ca/P ratio, and low bioavailability of calcium via high phytate content may pose problems for healthy bone development in populations that use grains as a staple food. It has in fact been reported that in populations where grains provide the major source of calories, osteomalacia, rickets and osteoporosis are common, even when there is sufficient sunshine to prevent vitamin D deficiency.

  The high phytate content of grains also affects the bioavailability of non-haem iron. A number of factors including phytate and fibre, tannins, lectins and phosphate  may contribute to the inhibition of  non-haem iron absorption. The high levels of phytate contribute most to the inhibition of non-haeme iron. To eliminate its inhibitory effect on non-haem iron absorption, phytate must be almost totally removed.

  Some studies of zinc absorption in rats and humans  have clearly demonstrated that consumption of phytate contained in whole grain grains (for example, wheat, rye, barley, oats) inhibits zinc absorption. The bioavailability of zinc from meat is four times greater than that from grains, and it implies that total dependence on grain- and plant-based diets (for example, vegetarian diets) may lead to impaired zinc metabolism in developed countries including Australia.

  coeliac disease) that grain peptides interact with and induce change in human physiology, and therefore elicit disease and dysfunction. Grains contain a variety of secondary metabolites which tend to be either toxic or anti-nutritional.

  diabetes mellitus, obesity and other diseases of insulin resistance, though chronic administration in animal models has been shown to induce deleterious histological changes to the pancreas and pancreatic hypertrophy. In view of the potential adverse effects these dietary anti-nutrients can have on human health, it is advisable to be cautious with alpha-amylase inhibitors in human foodstuffs.

  cardiovascular disease, and diverticulitis.

  There is no strong evidence for an association between fibre consumption and cancer; therefore, it is highly recommended that high-fibre foods, such as legumes and whole grain breads, grains, rice, and pasta, be consumed.

  Types and Composition of Food.

   For more information on nutrition, including information on nutrition and people, conditions related to nutrition, and diets and recipes, as well as some useful videos and tools, see Nutrition. 
  

  Reference

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  Article Dates:

  Modified: 3/6/2010

  Created: 14/2/2008

  
  Grains (Cereals)