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21 February 2022

Meat: has it passed its use-by-date?

In line with recent research Dr Jonathan White and Professor George Jelinek discuss the risks of eating meat, not only to general health but for specific medical conditions.

No, this is not an article about how to pick the freshest meat at the supermarket deli counter. Far from it. In fact, it’s the complete opposite. It’s time to reconsider whether meat should continue to be a mainstay of our daily meals. We need to weigh up the risks of eating meat, not only to general health but for specific medical conditions. In a greater and more urgent sense, the health of the planet is also at great risk. 

Background to the risks associated with eating meat

Few could argue that meat is not tasty, and it does contain some important vitamins and minerals, particularly vitamin B12 and iron. But most meat also contains significant amounts of saturated fat, and red and processed meats are now classed by the World Health Organisation (WHO) as Group 1 carcinogens, raising the risk of bowel cancer in particular, but also the risk of other common cancers. While some have disputed the role of saturated fat consumption in common western diseases, the best available evidence from large population studies shows that saturated fat is harmful to health, increasing the risk of death from common conditions such as heart disease, high blood pressure, and type 2 diabetes, the main killers in western countries.  But meat consumption may also be a problem in specific medical conditions that you might not have considered. 

Research linking meat and MS

The Neuroepidemiology (NEU) group at The University of Melbourne has published results from an ongoing longitudinal study of a large international group of people with multiple sclerosis. MS has long been considered a mystery disease with no cure. While there has been much suggestive data indicating a strong relationship between higher diet quality (including less saturated fat consumption) and less disability in MS, from North AmericanDutchAustralian and UK research, these studies have asked about the level of disability of participants at the same time as their dietary habits. And they have not specifically sought data on whether people with MS in their studies completely avoid meat.  

How the NEU research differs

The NEU research group has sought detailed data from people with MS at all stages of the illness, following them at regular intervals. They have looked at whether what a person with MS is eating today influences their level of disability years later. The hypothesis, strongly supported by literature from many previous research studies, is that the course of MS is very much influenced by a host of lifestyle risk factors, in the same way as heart disease and other common western health conditions.  

Approach and NEU findings that meat impacts MS

In this study, the NEU looked at detailed information about what people with MS were eating and correlated that with their degree of disability. What makes this research so compelling is that the researchers asked the simple question of whether or not participants ate meat.  They found that, due to the sampling of some groups following particular MS diets, their sample contained a sizeable proportion (around 30%) who did not eat meat at all, and of course the majority who did, so they had enough non-meat-eaters to meaningfully compare the groups, unlike other studies.  The researchers looked at whether or not participants ate meat at baseline, and what that meant for their disability levels 2.5 years later. They found that those who did not eat meat at the start of the study had around 75% lower risk of their disability getting worse 2.5 years later.  

This accords well with recently published research from the University of Connecticut and the University of Sydney. These researchers found that people with MS who ate meat changed their gut microbiome in ways that were metabolically harmful and worsened disability. This finely tuned balance of micro-organisms, and their effects on our immune system, mental and physical health is only really being discovered, and is now a rapidly expanding area of research. 

While there are now around a dozen pharmaceutical medications licensed for use in MS, and some have been shown to slow disability progression, side effects can be problematic as most have significant effects on the whole immune system. To date, most clinicians have not considered the evidence about the role of diet in MS progression strong enough to give specific advice to people with MS. This latest research substantially strengthens the evidence base. Whilst OMS supports the use of medication, this new information is invaluable for any person with MS, as it shows there is potentially something they can do for themselves that may reduce the risk of disability progression.  

Our thoughts

Multiple sclerosis appears then to be yet another disease for which meat consumption is problematic. Of course, OMS has been promoting this dietary advice now for many years, but this latest work strongly supports this stance. Given the wealth of personal health benefits from avoiding meat, and the reduction in greenhouse gas emissions by moving away from grazing animals for meat production, I personally think we perhaps have reached a point in our history where the whole population has to seriously consider changing dietary habits for better health, and indeed to ensure our survival as a species.   


References: 

  1. Alterations of host-gut microbiome interactions in multiple sclerosis