Population at Risk

FAO/WHO verbatim.

It is clear from Figure 12 that a positive calcium balance (i.e., net calcium retention) is required throughout growth, particularly during the first 2 years of life and during puberty and adolescence. These age groups therefore constitute populations at risk for calcium deficiency, as are pregnant women (especially in the last trimester), lactating women, postmenopausal women, and, possibly, elderly men. Our calculations for these groups, ultimately derived from Western European and North American data.

Recommendations by group

Infancy

American Academy of Pediatrics Committee on Nutrition. 1978. Calcium requirements in infancy and childhood. Pediatrics, 62: 826-832.

In the first 2 years of life, the daily calcium increment in the skeleton is about 100 mg (2.5mmol).

Williams, M.L., Rose, C.S., Morrow, G., Sloan, S.E. & Barness, L.A. 1970. Calcium and fat absorption in neonatal period. Am. J. Clin. Nutr., 23: 1322-1330.

Hanna, F.M., Navarrete, D.A. & Hsu, F.A. 1970. Calcium-fatty acid absorption in term infants fed Human milk and prepared formulas simulating Human milk. Pediatrics, 45: 216-224.

Widdowson, E.M. 1965. Absorption and excretion of fat, nitrogen, and minerals from “filled” milks by babies one week old. Lancet, 2: 1099-1105.

Shaw, J.C.L. 1976. Evidence for defective skeletal mineralisation in low birthweight infants: the absorption of calcium and fat. Pediatrics, 57: 16-25.

Widdowson, E.M., McCance, R.A., Harrison, G.E. & Sutton, A. 1963. Effect of giving phosphate supplements to breast-fed babies on absorption and excretion of calcium,

strontium, magnesium and phosphorus. Lancet, 2:1250-51.

The urinary calcium of infants is about 10 mg/day (0.25 mmol/day) and is virtually independent of intake and insensible losses are perhaps the same. Therefore,infants need to absorb some 120 mg (3 mmol) of calcium daily to allow for normal growth.What this represents in dietary terms can be calculated from calcium absorption studies in newborn infants, which suggest that the absorption of calcium from cow milk by infants is about 0.5 SD above the normal adult slope and from human milk is more than 1 SD above the normal adult slope. 

If this information is correct, different recommendations need to be made for infants depending on milk source. With human milk, an absorption of 120 mg (3mmol) of calcium requires a mean intake of 240 mg (6 mmol) (Figure 17) and a recommended intake of say 300 mg (7.5 mmol), which is close to the amount provided in the average daily milk production of 750 ml. With cow milk, calcium intake needs to be about 300 mg (7.5 mmol) to meet the requirement (Figure 17) and the allowance should be 400 mg(10 mmol) (Table 31).

Puberty and adolescence

Leitch, I. & Aitken, F.C. 1959. The estimation of calcium requirements: a reexamination. Nutr. Abstracts Revs., 29: 393-411.

As can be seen in Figure 12, a striking increase in the rate of skeletal calcium accretion occurs at puberty – from about ages 10 to 17 years. The peak rate of calcium retention in this period is 300–400 mg (7.5–10 mmol) daily;

Matkovic, V. 1991. Calcium metabolism and calcium requirements during skeletal modeling and consolidation of bone mass. Am. J. Clin. Nutr., 54: 45S-260S.

Abrams, S.A. & Stuff, J.E. 1994. Calcium metabolism in girls: current dietary intakes lead to low rates of calcium absorption and retention during puberty. Am. J. Clin. Nutr., 60:739-743.

Truswell, A.S. & Darnton-Hill, I. 1981. Food habits of adolescents. Nutr. Revs. 39:73-88.

Marino, D.D. & King, J.C. 1980. Nutritional concerns during adolescence. Pediatr. Clin. N. Am .J., 27: 125-139.

Matkovic, V. & Heaney, R.P. 1992. Calcium balance during Human growth: evidence for threshold behavior. Am. J. Clin. Nutr., 55: 992-996.

it occurs earlier in girls but continues longer in  boys. For a target value of 300 mg (7.5 mmol) for the skeleton, 100 mg (2.5 mmol) for urinary calcium, and insensible losses of 40 mg (1.0 mmol), the net absorbed calcium during at least part of this period needs to be 440 mg (11 mmol) daily. 

Abrams, S.A. & Stuff, J.E. 1994. Calcium metabolism in girls: current dietary intakes lead to low rates of calcium absorption and retention during puberty. Am. J. Clin. Nutr., 60:739-743.

Truswell, A.S. & Darnton-Hill, I. 1981. Food habits of adolescents. Nutr. Revs. 39:73-88.

Marino, D.D. & King, J.C. 1980. Nutritional concerns during adolescence. Pediatr. Clin.

N. Am .J., 27: 125-139. 

Even with assuming high calcium absorption (+2 SD), this requires an intake of 1040 mg (26.0 mmol) daily (Figure 17) and an allowance of 1300 mg (32.5 mmol) during the peak growth phase (Table 31). It is difficult to justify any difference between the allowances for boys and girls because, as mentioned above, although the growth spurt starts earlier in girls, it continues longer in boys. 

This recommended intake (which is close to that derived differently by Matkovic and Heaney is not achieved by many adolescents even in developed countries, but the effects of this shortfall on their growth and bone status are unknown.

Adults

FAO/WHO

As indicated earlier and for the reasons given, we accept that the mean apparent calcium requirement of adults in developed countries is about 520 mg (13 mmol) but that this is increased by insensible losses to some 840 mg (21 mmol) (Figure 14). This reasoning forms the basis of our recommended intake for adults of 1000 mg (Table 31).