Increased meat intake may up risk of several non-cancerous conditions

An increasing intake of unprocessed red meat and processed meat may be tied to an elevated risk of multiple medical conditions, according to a recent prospective study from the UK.

These findings were based on data of 474,985 middle-aged adults enrolled in the UK Biobank study between 2006 and 2010 who were followed up for a mean 8 years. The participants provided information on their dietary intake at baseline via a questionnaire. Information on hospital admission and mortality was obtained through linked electronic medical records. Approximately one-third of the population consumed unprocessed red and processed meat more than once a day.

A higher consumption of unprocessed red and processed meat was tied to an increased risk of ischaemic heart disease (IHD; adjusted hazard ratio [adjHR], 1.15, 95 percent confidence interval [CI], 1.07–1.23) per 70 g/day higher intake. It was also associated with an increased risk of pneumonia (adjHR, 1.31, 95 percent CI, 1.18–1.44), diverticular disease (adjHR, 1.19, 95 percent CI, 1.11–1.28), diabetes (adjHR, 1.30, 95 percent CI, 1.20–1.42), and colon polyps (adjHR, 1.10, 95 percent CI, 1.06–1.15; p_trend<0.001 for all) per 70 g/day higher intake. [BMC Med 2021;19:53]

The findings were consistent in separate assessments of intakes of unprocessed red meat (adjHRs per 50 g/day higher intake, 1.16, 1.22, 1.17, 1.21, and 1.08 for IHD, pneumonia, diverticular disease, diabetes, and colon polyps, respectively; p_trend<0.001 for all) and processed meat (adjHRs per 20 g/day higher intake, 1.09 [p_trend=0.001], 1.23, 1.11, 1.24, and 1.08, respectively; p_trend<0.001).

A higher intake of poultry was tied to an increased risk of diverticular disease (adjHR, 1.10, 95 percent CI, 1.04–1.17; p_trend=0.001), gastroesophageal reflux disease (adjHR 1.17, 95 percent CI, 1.09–1.26), gastritis and duodenitis (adjHR, 1.12, 95 percent CI, 1.05–1.18), gallbladder disease (adjHR, 1.11, 95 percent CI, 1.04–1.19), and diabetes (adjHR, 1.14, 95 percent CI, 1.07–1.21; p_trend<0.001) per 30 g/day higher intake.

“Interestingly, we saw that if we took into account people’s body weight [BMI], these associations reduced quite a bit, and this suggests that excessive body weight may contribute to these associations,” noted lead author Dr Keren Papier from the Nuffield Department of Population Health, University of Oxford, Oxford, UK.

Conversely, the risk of iron deficiency anaemia was reduced with a higher intake of unprocessed red meat (adjHR, 0.80 per 50 g/day higher intake, 95 percent CI, 0.72–0.90) or poultry (adjHR, 0.83 per 30 g/day higher intake, 95 percent CI, 0.76–0.90; p_trend<0.001 for both). These associations were less impacted by adjustment for BMI.

“The result that meat consumption is associated with a lower risk of iron-deficiency anaemia … indicates that people who do not eat meat need to be careful that they obtain enough iron through dietary sources or supplements,” said Papier.

Sensitivity analysis suggested that the associations between consumption of unprocessed red meat and diabetes and processed meat and IHD were not significant in never-smokers. Additionally, the increased consumption of unprocessed red and processed meat was linked to an elevated risk of haemorrhagic stroke in individuals diagnosed after ≥4 years of follow-up (HR, 1.53 per 70 g/day higher intake).

The sodium and saturated fatty acid content in unprocessed red and processed meat may be behind the elevated IHD risk, while gut microbiota metabolism may have a role to play in the unprocessed red meat–IHD association, said the researchers. Changes in microbial community structure and metabolism may also be involved in the meat–diverticular disease association.

“[Nonetheless,] additional research is needed to evaluate whether the differences in risk we observed in relation to meat intake reflect causal relationships, and if so, the extent to which these diseases could be prevented by decreasing meat consumption,” noted Papier.