Derivation of Allowances for Magnesium...continued.

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

The detailed studies of magnesium economy during malnutrition and subsequent therapy, with or without magnesium supplementation, provide reasonable grounds that the dietary magnesium recommendations derived herein for young children are realistic. Data for other ages are more scarce and are confined to magnesium balance studies. Some have paid little attention to the influence of variations in dietary magnesium content and of the effects of growth rate before and after puberty on the normality of magnesium-dependent functions.

21. Department of Health. 1991. Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. Report on Health and Social Subjects No. 41. London. HMSO. 

64. Health and Welfare Canada. 1992. Nutrition Recommendations: Health and Welfare, Canada. Report of the Scientific Review Committee, Ottawa, Supply and Services, Canada.

It is assumed that during pregnancy the foetus accumulates 8 mg and foetal adnexa accumulate 5 mg magnesium. If it is assumed that this dietary magnesium is absorbed with 50 percent efficiency, the 26 mg required over a pregnancy of 40 weeks (0.09 mg/day) can probably be accommodated by adaptation. A lactation allowance of 50–55 mg/day for dietary magnesium is made for the secretion of milk containing 25–28 mg magnesium (21 ,64).

30. Hu, J-F., Zhao, X-H. Parpia, B. & Campbell, T.C. 1993. Dietary intakes and urinary excretion of calcium and acids: a cross-sectional study of women in China. Am. J. Clin. Nutr., 58: 398-406.

An absorption efficiency of 50 percent is assumed for all solid diets; data are not sufficient to allow for the adverse influence of phytic acid on magnesium absorption from high-fibre diets or from diets with a high content of pulses. Not surprisingly, few of the representative dietary analyses presented in Table 45 fail to meet these allowances. The few exceptions, deliberatelyselected for inclusion, are the marginal intakes (232 ± 62 mg) of the 168 women of Changlecounty and the lower intake (190 ± 59 mg) of 147 women surveyed from Tuoli county China (30).