Meat or wheat for the next millennium?

fax +44 (0)1483 259297, email d. millward@surrey.ac. uk CR, colo-rectal. This issue of the Proceedings of the Nutrition Society includes short papers from some of the principal speakers of a debate on the theme of the 1998 Summer Meeting of the Nutrition Society at the University of Surrey: meat or wheat for the next millennium? The theme has several important strands. For international food policy, the issue relates to provision of adequate and appropriate food for a global population estimated to rise to more than eight billion by 2025, with an increasing demand for meat in developing and especially transitional societies. In contrast, in affluent societies meat intakes are falling as part of the changing dietary patterns of animal and plant food associated with the healthy diet. The issues are particularly complex and range from the nutritional adequacy and bioavailability of various plant–animal food combinations in relation to human metabolic demand for nutrients to the chronic responses to varying patterns of food intake in terms of human health and well-being, and the complex psycho-social issues of why people eat what they do. The latter issue includes the ‘is food bad for you? ’ question resulting from the headline issues of microbiological and toxicological hazards from meat and animal foods including salmonella, Escherichia coli, and bovine spongiform encephalopathy outbreaks, occurring with increasing frequency in the UK and seen by many to result from intensive animal food production. This situation provided the impetus for the proposal for a UK Food Standards Agency. The debate was organized on the basis of what can loosely be described as two pro-meat (Hill and Golden) and two pro-veg presentations (Key and Sanders), followed by a general discussion, with summaries of the arguments of Hill, Key and Sanders published here (Hill, 1999; Key et al. 1999; Sanders, 1999). The formal presentations were of necessity limited to very specific themes, of which the potential adverse influence of meat on chronic disease was addressed by each side. Hill (1999) specifically defended meat from its purported role in the aetiology of colo-rectal (CR) cancer. This was a high profile issue in 1997–8 after the World Cancer Research Fund (1997) report on diet and cancer concluded that red meat probably increased risk of CR cancer and intake should be limited to 80 g/d. Department of Health (1998) also recently reported on diet and cancer with similar advice initially issued by the Government but subsequently revised to the suggestion that heavy meat-eaters (> 140 g/d) should cut back. Hill (1999) robustly challenged the strength of the epidemiological evidence for a meat–CR cancer risk relationship used as the basis for the World Cancer Research Fund (1997) recommendation, arguing it to be a serious error of judgement likely to lead to a confused subsequent public health message. He points to striking European population data on meat intake and CR cancer risk, with the UK now consuming relatively little red meat as a result of the marked fall over the last few decades, during which time CR cancer mortality has increased to levels near the top of the European average. The surprising moment of the debate was the support for this view from the opposition. Key et al. (1999) presented findings of their own studies of the impact of meat-less diets on morbidity and mortality, including what are probably the most definitive data available on the issue. A collaborative analysis of 8300 deaths among 76 000 men and women of quite similar lifestyles in five prospective studies showed that in comparison with non-vegetarians, vegetarians had a lower BMI and plasma cholesterol concentration and a reduced mortality from IHD, possibly associated with lower intakes of saturated fat. However, meat-eating had no effect on mortality from colon cancer or any other cause of death. Clearly, as Key et al. (1999) argue, the prevention of 40 000 premature deaths from IHD by adopting a vegetarian diet is a compelling argument for this dietary change. If it proves to be a saturated-fat-mediated mechanism then that aspect of meat’s influence in the diet needs to be the target of the public health message. However, an argument for an adverse influence of meat through a meat–CR cancer relationship increasingly appears unsustainable, at least on the basis of existing data. Golden argued for the importance of meat in the provision of key bioavailable nutrients associated with child growth and development such as Fe, Zn and essential amino acids. Impaired height growth (stunting) is found in > 50 % of young children in some parts of the developing world, with adverse influences on morbidity and mortality (Waterlow, 1997), along with retardation of mental development as shown very clearly in recent work in Jamaica (Grantham-McGregor, 1992). Furthermore, for those children eating the more extreme vegetarian diets consumed in developed countries, such as the macrobiotic diet which can be limited to little more than whole grains, and which seriously impair growth and development, Dutch studies AMA pns99-12.fm Page 209 Thursday, June 24, 1999 3:00 PM