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Mortality from different causes associated with meat, heme iron, nitrates, and nitrites in the NIH-AARP Diet and Health Study: population based cohort study

BMJ 2017; 357 doi: https://doi.org/10.1136/bmj.j1957 (Published 09 May 2017) Cite this as: BMJ 2017;357:j1957

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Re: Mortality from different causes associated with meat, heme iron, nitrates, and nitrites in the NIH-AARP Diet and Health Study: population based cohort study

Red meat contains N-Glycolylneuraminic acid (Neu5Gc). I am surprised that Drs Potter and Etamadi et al make no mention of it. Neu5Gc occurs in virtually all red mammalian meat – with the exception of humans. In humans, the gene encoding CMP-N-acetylneuraminic acid hydroxylase mutated to an inactive form some three million years ago. It is thought that this conferred protection against an archaic form of malaria1.

When we eat red meat, Neu5Gc is absorbed and gives rise to an innate immune response. In the long term, this creates a chronic a low-grade inflammatory milieu. This will happen even if we eat fresh uncooked raw red meat2.

Such a milieu will promote cancers, insulin-resistance, hyperinsulinaemia and obesity, amongst other diseases.

I suspect that Neu5Gc will prove to be a major driving force of ill health.

01. Chou, H-H, Takematsu, H, Diaz, S et al A mutation in human CMP-sialic acid hydroxylase occurred after the Homo-Pan divergence. Proceedings of the National Academy of Sciences, 1998;95:11751–6.
doi:10.1073/pnas.95.20.11751

02. Samraj, AN, Pearce, OM, Läubli et al A red meat-derived glycan promotes inflammation and cancer progression. Proceedings of the National Academy of Sciences. 2015;112:542–7.
doi: 10.1073/pnas.1417508112

Competing interests: No competing interests

25 May 2017
John M EVANS
Consultant - retired
Nuffield Department of Anaesthetics
John Radcliffe Hospital, Oxford, OX3 9DU