Cereals phytic acid

Several dietary constituents decrease the bioavailability of calcium in food. Increasing fiber intake by, for example, replacing white flour by whole wheat flour in a typical Western diet has long been associated with negative calcium balance even when calcium intakes meet recommended levels. Likewise, the fiber in fruits and vegetables can cause negative calcium balance. In cereals, phytic acid is the main constituent of fiber that binds calcium, making it unavailable for absorption. The... 

Within the gut, oxidative damage may be prevented by phytic acid, obtained from cereals and vegetables (Graf et al., 1987), and by soluble non-starch polysaccharides like pectin (Kohen et al., 1993). The use of antioxidant vitamins in the treatment of inflammatory bowel disease has also been su ested (Evans et al., 1990). 

HV057 Sasatamoinen, M., S. Plaami, J. Kumpulainen, and O. Rantanen. Concentrations of water soluble and in- HV068 soluble beta-glucan and phytic acid in 6 row and 2-row barley. Cereal Res Commun 1991 19(4) 391-397. 

Gahlawat, P., and S. Sehgal. Phytic acid, saponins, and polyphenols in weaning food prepared from oven-heated green gram and cereals. Cereal... 

Some Andean potatoes have iron content comparable to levels found in some cereals (rice, maize, and wheat Scurrah et al., 2007). Potato iron should be quite bioavailable because it has very low levels of phytic acid, unlike the cereals. 

Maurice et al. (1985) evaluated naked oats as a potential feedstuff for poultry feeding and reported that this grain was superior to maize in AA profile and mineral content. Total lipid was 68.5 g/kg with a content of 309 g/ kg linoleic acid, which is higher than that of most cereal grains, and contributed to a relatively high ME value of 13.31 MJ/kg. The naked oats contained 4 g/kg total P and a phytic acid concentration of 10.7g/kg. 

Phytate. Phytic acid is an organic polyphosphate found widely in plants, particularly cereals, nuts and legumes. It has been shown to complex with various divalent cations in the gastrointestinal tract and thus reduce mineral bioavailability (33,44,52). Davis et al. (53) reported that feeding a diet based on isolated soybean... 

Most of our knowledge about factors affect zinc absorption ( , 10, 18) comes from studies on animals. The most extensive studies are made on the affect of phytic acid, which is present in vegetables and unrefined cereal products. Decreased zinc absorption has been found both when substantial amounts of sodium-phytate are added to the diet and when the diets are based on phytic-containing food, such as soy beans. The explanation of this is that a complex between Zn and phytic acid is made, resulting in a decreased bioavailability. 

Lasztity, R., and Lasztity, L., 1990, Phytic acid in cereal technology. Adv. Cereal Sci. Technol. 10 309-371. 

Bryant, R.J., Dorsch, J.A., Rutger, J.N., and Raboy. V, 2005, Amount and distribution of phosphorus and minerals in low phytic acid 1 rice seed fractions. Cereal Chem. 82 517-522. 

Phytates found in cereals, legumes, nuts and oil seeds form complexes with minerals, the mineral-phytate complexes in decreasing order of stability being zinc > copper > nickel > cobalt > manganese > calcium. Thus, zinc is affected most. An increase in pH results in phytic acid becoming more ionized and initiates binding to cations. 

Iron deficiency anemia occurs mainly in infants, children, and fertile women. For this reason, a variety of foods, including infant formula and infant cereals, is fortified with iron. Ferrous sulfate is a form of iron that is most readily absorbed by the gut, but when added to dry cereals it can promote their spoilage and rancidity. For this reason, dry cereals are fortified with elemental iron particles, ferric pyrophosphate, or ferrous fumarate (Davidsson et ah, 1997). Ascorbic add may also be added to the cereal to enhance iron absorption. To view some of the numbers, infant cereals may contain 75 mg iron/kg cereal (1.3 mmol iron/kg), 1 mmol phytic acid/kg, and 2.6 mmol ascorbic acid/kg (Davidsson et cd., 1997). Although phytic acid impairs iron absorption, the added ascorbate serves to prevent this effect. An alternate method for preventing phytate from impairing iron absorption is to treat the food with the enzyme phytase. A parent interested in enhancing a child s iron absorption can easily feed a child some orange juice, but it would not be practical to pretreat the child s cereal with phytase. A typical availability of ferrous sulfate in infants is about 3-5% (with no ascorbate), and 6-10% (with ascorbate). Ascorbate is effective when present in a twofold molar excess over the iron. 

An increase in consumption of whole grain flour products is the nutritional aim in Norway. The high content of dietary fiber or factors associated with it, however, present in bran and whole grain flour, may interfere with the bioavailability of iron as indicated by several authors (2,3,4). Phosphate and especially phytic acid present in unrefined cereal products have frequently been said to be potent inhibitors of iron absorption (5,6). 

In conclusion, the insoluble fraction, which is by far the main part of cereal dietary fiber, does not bind measurable amounts of ash after digestion with proteolytic and amylolytic enzymes under conditions similar to those in the human gastrointestinal tract. All the binding capacity seems to be due to the small soluble fraction in which the polysaccharides but also most of the phytic acid is recovered. 

Lolas, G.M. N. Palamidas P. Markakis. The phytic acid—Total phosphorus relationship in barley, oats, soybeans and wheats. Cereal Chem. 1976, 53, 867-871. 

Nuts, seeds, and grains are not considered as sources of organic acids. Other than amino acids and fatty acids, they contain phenolic acids and phytic acid. Phytic acid and its salts, phytats, are regarded as the primary storage form of both phosphate and inositol in seeds, mostly within the hulls. The phytic acid content of cereals (whole grain) varies from 0.5% to 2.0% [21],... 

Lasztity, R. and Lasztity, L., Phytic acid in cereal technology. In Advances in Cereal Science and Technology, Vol. 10. Y. Pomeranz (Ed.), American Association of Cereal Chemists, Inc., St. Paul, MN, pp. 309-371, 1990. 

The significance of cereals in the production of experimental rickets was discovered by Mellanby (1921,1925). Bruce and Callow (1934) identified the unknown factor as phytic acid. The discussion here will be confined to the relation with vitamin D. 

Oats have a thicker layer of cell walls in the subaleurone region of the kernel than other cereals do. In addition to p-glucan, oats are a source of many beneficial health compounds (Peterson 2001), including antioxidants such as vitamin E (tocols), phytic acid, phenolic compounds, and avenanthramide flavonoids and sterols are also present. Antioxidants assist in maintaining the stability of processed oat products. Oats can also stabilize oils and fats against rancidity. 

Liang, J., Z. Li, K. Tsuji, K. Nokano, M. J. R. Nout, and R. J. Hamer. 2008. Milling characteristics and distribution of phytic acid and zinc in long-, medium-, and short-grain rice. Journal of Cereal Science 48 83-91. 

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