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Milk intake and risk of mortality and fractures in women and men: cohort studies

BMJ 2014; 349 doi: (Published 28 October 2014) Cite this as: BMJ 2014;349:g6015

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Modern milk production on an industrial scale involves administration of various synthetic substances to dairy cows to enhance milk production. The dairy milk has significant residues of these synthetic substances such as hormones, antibiotics and analgesics [1]. Sadly, these negative aspects of ‘mass produced milk’ has not been discussed in the paper at all [2].

For instance, the paper deals with cohorts recruited between 1987 and 1997. But until the European wide ban in 2000, recombinant bovine somatotropin (rBST) was used to enhance milk production. The hormone rBST can affect hormonal and metabolic growth factors including human serum insulin-like growth factors (IGF) which in turn can increase the risk of cancer [3][4]. A large European cross-sectional showed that intake of dairy was an important dietary determinant of serum IGF-I [5].

Analysis of milk for presence of these substances would have provided a more plausible explanation for the mortality effect.

1 Jurado-Sánchez B, Ballesteros E, Gallego M. Gas Chromatographic Determination of N-Nitrosamines, Aromatic Amines, and Melamine in Milk and Dairy Products Using an Automatic Solid-Phase Extraction System. J Agric Food Chem 2011;59:7519–26.

2 Michaëlsson K, Wolk, A, Langenskiöld, S, et al. Milk intake and risk of mortality and fractures in women and men: cohort studies. BMJ;349:g6015.

3 Allen NE, Appleby PN, Davey GK, et al. The associations of diet with serum insulin-like growth factor I and its main binding proteins in 292 women meat-eaters, vegetarians, and vegans. Cancer Epidemiol Biomark Prev Publ Am Assoc Cancer Res Cosponsored Am Soc Prev Oncol 2002;11:1441–8.

4 World Health Organization. Joint FAO/WHO Expert Committee on Food Additives (JECFA). Toxicological evaluation of certain veterinary drug residues in food. Monograph 41. (accessed 31 Oct2014).

5 Crowe FL, Key TJ, Allen NE, et al. The association between diet and serum concentrations of IGF-I, IGFBP-1, IGFBP-2, and IGFBP-3 in the European Prospective Investigation into Cancer and Nutrition. Cancer Epidemiol Biomarkers Prev 2009;18:1333–40. doi:10.1158/1055-9965.EPI-08-0781

Competing interests: No competing interests

31 October 2014
Santhanam Sundar
Consultant Oncologist
Nottingham University Hospitals NHS trust
Dept of Oncology