Are formula milks good enough for our children? They certainly got a bad press this weekend, when the Department of Health ordered the withdrawal from sale of Milupa's Milumil for Hungrier Bottle Fed Babies, a brand which is fed to about 25,000 British infants, after it was linked by a government study with a rare form of salmonella. The study found that of 12 children who suffered salmonella anatum between last October and earlier this month, at least 10 had used Milumil, against just three or four in the control group.
A previous scare occurred in May last year when nine brands of infant feed tested by the Ministry of Agriculture were found to contain phthalates, chemicals which in animal tests have been found to reduce fertility. Many health professionals are now calling for better quality control of formula milks, although admittedly incidents such as the one involving salmonella are rare. As for the phthalates, studies have shown that breast milk also contains substances that mimic natural hormones. Whether these chemicals present a risk at the levels found in either breast milk or formula is still under discussion.
The main problem with formula milk is that it is based on cows' milk - great for calves but, with too little sugar, too much protein and sodium, and the wrong kind of fat, not the ideal food for babies. However, unlike the old National Dried Milk - which contained so many excess minerals that babies found it difficult to excrete the surplus, and which was withdrawn in 1977 - today's powdered milk is modified to resemble breast milk as closely as possible: protein, sodium and calcium are reduced, butter fat is replaced by vegetable fats, and lactose and essential vitamins and minerals are added.
But despite these changes, formula milk remains qualitatively different from breast milk, lacking many of the substances which make it so beneficial. Unlike the latter it does not have antibodies which protect against infection, particularly gastroenteritis and respiratory illness. Nor does it contain enzymes such as lipase which help the digestion of fat, resulting in the absorption of fat-soluble vitamins; or lactoferrin, a substance which binds iron so that the bacteria cannot get at it, and which also confers protection against infection.
There are other important, and less well-known, differences between breast and bottle. Formula, for example, cannot adjust itself during a feed, so that the baby first gets foremilk, which satisfies thirst, and then the richer hindmilk which satisfies appetite. It cannot imitate the breast milk of an individual mother, designed for her baby alone, and which varies in composition: containing more water and less fat in hot weather, for example.
Perhaps most important, most formula milks still do not contain the long- chain polyunsaturated fats, or LCPs, which are found in breast milk and which have been linked in various studies to optimum neurological development. Although LCPs are added to formula for premature babies, so far only two manufacturers, Milupa and Farleys, have launched a brand for full-term babies with added LCPs, derived from either egg or fish oils.
Despite the advantages of breast milk, some women will still choose to bottle-feed. Those who do so should first try a whey-based brand rather than the casein-based ones for hungrier babies, because the former resemble breast milk more closely. Soy-based formula, thought by some doctors to protect against allergy, has been found to contain phytoestrogens, another group of hormones linked to infertility in animals. Although soy formula is not thought to pose a risk to infants, it should only be used on medical grounds or after consultation with a doctorn