Breast milk containing calcium

Conn et al. [8] made a detailed discussion about the average daily intake of lactic acid from food sources that was estimated as 924 mg/day for those 2 years of age and older. In addition, 377 mg/day for calcium lactate was estimated for the same group. Regarding infants consumption of lactic acid, breast milk contains 60 mg/L of L-lactic acid with an estimated daily intake as high as 10 mg/kg. From a different perspective, a breast-fed infant weighing 4 kg would consume about 36 mg of L-lactic acid/day from both, human and formula milk. 

During pregnancy and lactation, some of the calcium stored in the bones of the mother is released and transferred to the fetus through the placenta or to an infant through breast milk. If the mother s bones contain strontium from previous exposure, a similar release and transfer may occur. If a mother is newly exposed to strontium, some will be transferred to the fetus, although the percentage of transfer is likely to be low. 

The calcium content of human milk is only about 30 mg per 100 ml, but, provided that the volume produced by the mother is sufficient, the infant s need will be covered. Milk is low in iron but infants accumulate a store of iron during intrauterine life, and this is usually sufficient for the first 4-6 months of independent existence. After this time it is important to supplement the milk diet with iron-containing foods such as strained meat and vegetables. Milk is also relatively deficient in vitamins C and D. The vitamin C content of breast milk is usually adequate, but infants fed on cow s milk may need a supplementary source. Although fresh orange juice and rose hip syrup are good sources, it is undesirable to accustom children to sweet drinks at an early age since later on these can have disastrous effects on the teeth. 

Sometimes, these effects may be prevented by extra dietary vitamin D, or by exposure to sunlight. However, newborn infants, whose kidneys do not excrete excess phosphate as well as those of older infants and children, may develop high blood levels of phosphate and have seizures when they are fed evaporated milk containing phosphate additives.The seizures are attributed to the fact that cow s milk contains almost four times the calcium and over six times the phosphorus present in human breast milk. Furthermore, extra phosphate is often added to evaporated milk to lengthen its shelf life. Hence, newborn babies fed evaporated milk (diluted with an equal volume of water) may receive between seven and eight times the phosphorus they would get from the same amount of human breast milk. An elevation of the blood level of phosphate causes a corresponding drop in the level of ionized calcium. The direct cause of the milk-induced seizures is the lack of sufficient ionized calcium in the blood. 

Vitamin D Vitamin D enhances the efficiency of the small intestine to absorb calcium and phosphorus from the diet and thus helps to maintain normal serum levels of these minerals. Vitamin D deficiency in infants and children results in inadequate mineralization of the skeleton, causing rickets, which is characterized by various bone deformations. The major source of vitamin D is its formation in the skin as a result of exposure to sunlight. Dietary sources include fortified foods, such as milk and cereals, and certain fish. Infant formula is fortified with vitamin D in many countries. Because human milk contains only low amounts of vitamin D, breast-fed infants who do not receive either supplemental vitamin D or adequate exposure to sunlight are at risk for developing vitamin D deficiency. Subclinical vitamin D deficiency can be assessed by measuring serum 25-hydroxyl-vitamin D deficiency occurs months... 

A breast-fed infant receives about 60 mg of calcium per kilogram of body weight (300 mg/liter of milk) and retains about two-thirds of this. By contrast, an infant fed a standard cow s milk formula containing added carbohydrate (500 to 700 mg of calcium per liter) receives about 170 mg of calcium per kilogram but retains 25 to 30%. Although the breast-fed infant has less calcium available, its calcium needs are fully met. Thus, the NRC recommended allowance for Infants to 5 months is set at 400 mg per day. 

In the UK, it is recommended that infants who are not breast fed are fed modified milks until at least 6 months of age. These contain less solute, protein, sodium, calcium and phosphorus than cows milk. The Codex Alimentarius lays down international standards for infant feeds Some modified milks are based on demineralised whey and milk to reduce the protein content and change the whey casein ratio examples are given in Table 1. This provides an amino acid composition more closely resembling that of human milk but does not overcome the problem that beta-lactoglobulin and other cows milk proteins are introduced and the anti-infective factors provided by human milk are absent. 

---