Tucking into beef could be good for your health – but not the planet’s

As the barbeque season gets into full swing, New Zealand researchers are investigating whether certain kinds of red meat could actually protect against heart disease.

Researchers have recruited men aged 35-55 willing to eat free meat three times a week for eight weeks in the name of science, according to a press statement from the Liggins Institute.

Participants are supplied with either grass-fed Wagyu beef, grain-finished beef or soy-based meat alternative (they can’t choose which).

The study is looking at how the complex lipids (fats) in high quality, unprocessed red meat affect heart health, using the vegetarian protein group as a control. It follows earlier evidence that eating Wagyu beef in moderation may help protect against heart disease.

The beef, from specially bred and fed cows, is rich in a fat called conjugated linoleic acid, or CLA, and several other so-called ‘good fats’.

Study lead Professor David Cameron-Smith, from the University of Auckland-based Liggins Institute, says red meat is an excellent source of protein and rich in vitamins and minerals, such as iron, but has been linked to an increased risk for heart disease and colon cancer.

Almost all of the evidence for those links comes from large epidemiological studies, which involve identifying associations between people’s self-reported diet and their health status years later.

“The trouble is, it’s hard to tell whether these associations are linked to meat, or other diet and lifestyle factors,” says Professor Cameron-Smith.

“Another issue is that many studies do not separate out the effects of fresh and preserved, or processed, red meat. The link to colon cancer is clear for processed meat. But very few scientific studies – this is the first in New Zealand – have extended this research to actually piece together whether a modest intake of good quality, fresh red meat has any positive or negative impacts on health.” 

The other two researchers running the study, called the CLIMB Study, are Liggins Institute Research Fellow Dr Amber Milan and AgResearch Senior Research Scientist Dr Emma Bermingham.

Dr Milan says the difference in fat profiles between the Wagyu and standard (grain-finished Angus-mixed breed) beef is to do with both the breed of the cow and feeding practices.

“Grass-fed cows naturally have more omega-3 and other ‘good fats’ like DPA and CLA, which have anti-inflammatory properties. CLA is unique to ruminants because it is produced by the bacteria in their guts.”

Previous studies by Professor Mark Vickers and Dr Clare Reynolds at the Liggins Institute found that pregnant rats on a high-fat diet that were given CLA supplements gained weight but had a reduction in several negative health effects that usually go hand in hand with weight gain, such as inflammation and glucose intolerance. Furthermore, the offspring of these supplemented mothers showed some enduring health benefits into adulthood, including improved metabolic and reproductive health.

Dr Milan said the study

” … will hopefully show whether these beneficial fats in meat have similar positive health effects in humans, and could potentially help prevent heart disease later in life.”

The researchers recruited participants who are on the heavy side with slightly high cholesterol, aged 35-55 years and consuming red meat in their regular diet. They receive three servings of red meat (or alternative) for eight weeks. Before and after going on the diet, they visit the institute to give blood, urine and stool samples.

Researchers will analyse these samples to look for changes in health indicators such as blood lipids, including cholesterol, and changes in body fat composition, and check for gut microbiome changes, where they expect to see clear differences between the red meat and vegetarian groups.

Results are expected mid-2019. To find out more about Liggins Institute research, visit the clinical studies page.

But an item posted on Sciblogs a few days ago is headed Why you shouldn’t eat beef.

The posted, written by Marcus Wilson  and syndicated from Physics Stop (you can view the original source here) begins:

“Don’t eat beef.”

 Such a statement does not go down well in New Zealand,  especially in Waikato, where the cow reigns supreme.

I don’t say it as someone who wants to peddle a “Meat is Murder” message. I don’t believe that at all. I say it as someone who wants New Zealand to take Climate Change seriously.

Quite simply, the writer says, producing a serving of beef produces a staggering amount of carbon dioxide. The post is illustrated with a diagram from Poore and Nemecek (2018).

To put the data into context, the writer says driving 100 km in a car produces around 14 kg of carbon dioxide.  One serving of high-impact beef tops this. Even a low impact serving of beef is similar to driving about 30 km in a typical car, carbon dioxide-wise.

Putting it another way, about 10 kWh (10 units) of electricity from the coal-fired Huntly power station will give about 9 kg of carbon dioxide, a smidgen more than an average serving of beef.

The post continues:

But, one should also observe that meat, in general, is bad news for the Earth’s climate. While beef is by far the largest offender, one should note that plant based-foods, in general, are far better than all animal-based foods. So, while I won’t claim that it is morally wrong to eat meat on the basis of the feelings of animals, as some do, I will claim that it is morally wrong to eat meat, especially beef, (to any substantial degree) on the basis of climate change.

Actually, it is interesting to delve into Poore and Nemecek’s data a bit more.  As well as CO2 emissions, they look at land use, phosphate use & eutrophication, and water use. The variation across a food type from the ‘best’ to the ‘worst’ can be staggering. For example, the median stress-weighted water use for producing one ‘nutritional unit’ of tofu is 20 litres, but the mean is 3 thousand litres!  What this means is that a lot of production requires very little irrigation, while a minority of production requires huge volumes. (It is also an example of why one needs to be careful with quoting medians and means, and how a story can be spun to suit one’s own ends by picking the ‘right’ statistic.) One obvious conclusion that Poore and Nemecek make is that we (as a world) must be smarter in how we use agricultural land and resources

Finally, in relation to a previous post and climate change, the writer says it is good to hear that the “right-to-repair” campaign is making some progress, in Europe at least…  https://www.bbc.com/news/science-environment-46797396

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