Summer 97 Newsletter INFACT Canada


Exposure of infants to phyto-oestrogens from soy-based infant formulas

Setchell, K. D. R. et al. Lancet 350:23-27, 1997

Concerned that bioactive phyto-oestrogens, the isoflavones genistein, daidzein, and their glycosides present in high concentrations in soy based formulas can cause adverse effects in infants fed soya based formulas, the researchers wished to determine the extent to which infants are exposed. The plasma concentrations of genistein and daidzein were measured in 4-month-old infants; 7 infants fed the soy-based formulas, 7 infants fed cow’s milk formula and 7 fed human milk; and soy-based formulas were analysed according to type and amounts of isoflavones present. The mean concentration of isoflavones present was 32-47 µg/ml. Infants fed soy based formulas had mean concentrations of genistein and daidzein of 684 ng/ml and 295 ng/ml respectively; infants fed cow’s based formulas 3.2 and 2.1 ng/ml; and infants fed human milk 2.8 and 1.4 ng/ml.

Exposure from phyto-oestrogens in the soy products was found to be 6 to 11 times higher on a per body weight basis than the dose that has hormonal effects in adults consuming soy foods. Also the circulating levels of isoflavones in the soy-fed infants were 13,000 to 22,000 times higher than normally found in young infants. These levels they conclude may be sufficient to “exert biological effects.” Although the authors conclude that there is no evidence to suggest that levels of phyto-oestrogens present in infant diets has adverse effects (this study received funding from Wyeth), however, potential effects of the steroid-hormone “imbalance,” include competition with enzymes that metabolize steroids, drugs and xenobiotics, or by affecting gonadal function.

The International Code of Marketing of Breastmilk Substitutes: A Model for Assuring Children’s Nutrition Rights Under the Law.

Margulies, L. The International Journal of Children’s Rights, 1997

Ms Margulies, a lawyer and longtime proponent of breastfeeding women’s rights, outlines the relationship between the International Code and the United Nations Universal Declaration of Human Rights. The human rights that the Code attempts to protect are the rights to health and life, the rights to food and nutrition, and the rights of women to full and accurate information on which to base decisions affecting their children’s health. By emphasizing the vital importance of breastfeeding to the majority of the world’s children and their mothers, the author frames the International Code as emanating from the human rights instruments of the United Nations. From the historical context of the right to life, dignity and freedom, as expressed in political and civil rights along with economic, cultural and social rights, the International Code translates these rights into a specific document that can be transcribed into national law.

The health and nutrition rights protected by the International Code have since 1989 also been incorporated into the Convention of the Rights of the Child–“the right to the highest attainable standard of health.” The author gives a number of national examples where these instruments have been adopted as law–such as India, Zimbabwe, China, Guatemala and Costa Rica.

Pacifier Use and Short Breastfeeding Duration: Causes, Consequences or Coincidence?

Victora, C. G. et al. Pediatrics 99: 445-453, 1997

Victora et al, who have previously related pacifier use to shorter duration of breastfeeding, interviewed a cohort of 650 mothers and infants at one, three and six months, to determine if this association is causal or if self-selection of mothers may play a role.

Pacifier use was common with 85 per cent of the infants at 1 month. Intense, frequent use at 1 month was more than 4 times likely to stop breastfeeding by 6 months of age than non-users. Pacifier users also had fewer breastfeedings per day than non-users. After adjustment for confounding variables, pacifier use was still associated (odds ratio 2.1) with the stoppage of breastfeeding. Included in the study was an ethnographic analysis which showed the use of pacifiers was considered a positive behaviour and mothers actively encouraged their use. A large number of mothers used pacifiers to end breastfeeding or to lengthen the time between breastfeeds.

In conclusion, pacifiers were found to be an effective weaning mechanism for mothers, who had breastfeeding difficulties, but for mothers who were confident about breastfeeding, pacifiers had much less impact. Programs to reduce pacifier use need to be in concert with helping women deal with difficulties in breastfeeding.

Of interest: Hypoglycemia and the Newborn A Review of Literature, World Health Organization Division of Child Health and Development and Maternal and Newborn Health/Safe Motherhood.
Copies available from INFACT Canada Breastfeeding Information Resource Centre Tel: (416) 595-9819

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