Dean asked for references to the notion that phytic acid in cereal grains causes calcium depletion. In 1992 Professor Harold H. Sandsted, who is Interim Editor-in-Chief of the American Journal of Clinical Nutrition, the most important journal of nutrition, noted that "the evidence seems overwhelming that high intakes of fiber sources that are also rich in phytate can have adverse effects on mineral nutrition of humans" and that, "in view of the [reviewed] data, it appears that some health promoters who suggest that U.S. adults should consume 30-35 g dietary fiber daily either have not done their homework or have simply ignored carefully done research on this topic" [1]. My own opinion is that authorities who advocate cereals in a prudent western diet largely do so for practical reasons [2]. So let's look do the homework. Whole meal cereals and other seeds have in their shells phytic acid which strongly binds to minerals like calcium, iron, zinc and magnesium to form insoluble salts, phytates [1, 3-7]. It is well known that whole meal cereals by this mechanism decrease the absorption of such minerals [1, 3-7]. There is apparently no adaptation to a habitual high intake of phytic acid [8] which is an important contributing cause of iron deficiency in third world countries and possibly in the western world [9]. It is also an important cause of mineral deficiency in vegetarians [10-12]. The most commonly studied minerals are bound to phytic acid possibly in the following decreasing order: calcium > iron > zinc > magnesium (Fredlund K, personal communication). Mellanby found back in the 30s that young dogs got rickets when they were fed oatmeal [13]. He was made aware of the calcium-binding effect of phytate [14] and showed that phytate was the dietary factor responsible for inhibition of calcium absorption by oatmeal as well as the induction of rickets in dogs [15]. McCance and Widdowson found adverse effects of bread prepared from high-extraction wheat flour on retention of essential metals by humans [16]. They also showed that destruction of phytate improved retention of calcium [17]. Substantial evidence have later firmly established this negative impact of phytate [1, 3-7]. Not even rats seem to be fully adapted to graminivorous diets since phytate adversely affects mineral absorption in them as well [18]. In the archaeological record, rickets is rare or absent in preagricultural human skeletons, while the prevalence increases during medieval urbanization and then explodes during industrialism [19]. In the year 1900, an estimated 80-90 per cent of Northern European children were affected [20, 21]. This can hardly be explained only in terms of decreasing exposure to sunlight and descreased length of breast-feeding. An additional possible cause is a secular trend of increasing intake of phytate since cereal intake increased during the Middle Ages (Morell M, personal communication) and since old methods of reducing the phytate content such as malting, soaking, scalding, fermentation, germination and sourdough baking may have been lost during the agrarian revolution and industrialism by the emergence of large-scale cereal processing. The mentioned methods reduce the amount of phytic acid by use of phytases, enzymes which are also present in cereals [22-26]. These enzymes are easily destroyed during industrial cereal processing [27, 28]. It should be noted that dietary fiber alone has no impact on mineral absorption [5, 29] why a high intake of fiber from fruits and tubers can safely be recommended, at least from this point of view. Best regards to all of you, Staffan 1. Sandstead HH. Fiber, phytates, and mineral nutrition. Nutr Rev 1992; 50: 30-1. 2. Walker ARP, Walker BF I. I. Fiber, phytic acid, and mineral metabolism. Nutr Rev 1992; 50: 246-7. 3. Spivey Fox MR, Tao S-H. Antinutritive effects of phytate and other phosphorylated derivatives. In: Hathcock JN, ed. Nutritional Toxicology. New York: Academic Press, 1989: 59-96. vol 3). 4. Harland BF. Dietary fibre and mineral bioavailability. Nutr Res Rev 1989; 2: 133-47. 5. Rossander L, Sandberg A-S, Sandstr=F6m B. The influence of dietary fibre on mineral absorption and utilisation. In: Schweizer TF, Edwards CA, ed. Dietary fibre - a component of food. Nutritional function in health and disease. London: 1992: 6. Sandberg AS, Hasselblad C, Hasselblad K, Hulten L. The effect of wheat bran on the absorption of minerals in the small intestine. Br J Nutr 1982; 48: 185-91. 7. Morris ER. Phytate and dietary mineral bioavailability. In: Graf E, ed. Phytic acid: Chemistry and applications. Minneapolis: Pilatus Press, 1986: 57-76. vol 4). 8. Brune M, Rossander L, Hallberg L. Iron absorption: no intestinal adaptation to a high-phytate diet. Am J Clin Nutr 1989; 49: 542-5. 9. Hallberg L, Rossander L, Skanberg AB. Phytates and the inhibitory effect of bran on iron absorption in man. Am J Clin Nutr 1987; 45: 988-96. 10. Harland BF, Smith SA, Howard MP, Ellis R, Smith JJ. Nutritional status and phytate:zinc and phytate x calcium:zinc dietary molar ratios of lacto-ovo vegetarian Trappist monks: 10 years later. J Am Diet Assoc 1988; 88: 1562-6. 11. Ellis R, Kelsay JL, Reynolds RD, Morris ER, Moser PB, Frazier CW. Phytate:zinc and phytate X calcium:zinc millimolar ratios in self-selected diets of Americans, Asian Indians, and Nepalese. J Am Diet Assoc 1987; 87: 1043-7. 12. Gibson RS. Content and bioavailability of trace elements in vegetarian diets. Am J Clin Nutr 1994; 59(5 Suppl): 1223S-1232S. 13. Mellanby E. A story of nutrition research.Baltimore: Williams & Wilkins Co, 1950 14. Bruce H, Callow R. Cereals and rickets. The role of inositolhexaphosphoric acid. Biochem J 1934; 28: 517-28. 15. Harrison D, Mellanby E. Phytic acid and the rickets-producing action of cereals. Biochem J 1934; 28: 517-28. 16. McCance R, Widdowsos E. Mineral metabolism of healthy adults on white and brown bread dietaries. j Physiol 1942; 101: 44-85. 17. McCance R, Edgecombe C, Widdowson E. Mineral metabolism of dephytinized bread. J Physiol 1942; 101: 18. Fairweather TS, Wright AJ. The effects of sugar-beet fibre and wheat bran on iron and zinc absorption in rats. Br J Nutr 1990; 64: 547-52. 19. Stuart-Macadam PL. Nutritional deficiency diseases: a survey of scurvy, rickets, and iron-deficiency anemia. In: Is=E7an MY, Kennedy KAR, ed= . Reconstruction of life from the human skeleton. New York: Wiley-Liss, 1989: 201-22. 20. Gibbs D. Rickets and the crippled child: an historical perspective [see comments]. J R Soc Med 1994; 87: 729-32. 21. Hernigou P. Historical overview of rickets, osteomalacia, and vitamin D. Rev Rhum Engl Ed 1995; 62: 261-70. 22. Sandberg AS. The effect of food processing on phytate hydrolysis and availability of iron and zinc. Adv Exp Med Biol 1991; 289: 499-508. 23. Svanberg U, Sandberg A-S. Improved iron availability in weaning foods using germination and fermentation. In: Southgate DAT, Johnson IT, =46enwick GR, ed. Nutrient Availability: Chemical and biological aspects. Cambridge: Cambridge University press, 1989: 179-81. 24. Larsson M, Sandberg A-S. Phytate reduction in bread containing oat flour, oat bran or rye bran. J Cereal Sci 1991; 14: 141-9. 25. Navert B, Sandstrom B, Cederblad A. Reduction of the phytate content of bran by leavening in bread and its effect on zinc absorption in man. Br J Nutr 1985; 53: 47-53. 26. Caprez A, Fairweather TS. The effect of heat treatment and particle size of bran on mineral absorption in rats. Br J Nutr 1982; 48: 467-75. 27. Sandberg A-S. Food processing influencing iron bioavailability. In: Hallberg L, Asp N-G, ed. Iron Nutrition in Health and Disease. London: John Libbey, 1996: 349-58. 28. Sandstrom B. Food processing and trace element supply. In: Somogyi JC, Muller HR, ed. Nutritional Impact of Food Processing. Bibl Nutr Dieta. Basel: Karger, 1989: 165-72. 29. Andersson H, Navert B, Bingham SA, Englyst HN, Cummings JH. The effects of breads containing similar amounts of phytate but different amounts of wheat bran on calcium, zinc and iron balance in man. Br J Nutr 1983; 50: 503-10.