Michael Mosley continues his Trust Me I’m a Doctor series looking at the health benefits and risks of diet by considering ht e consumption of red meat and other animal products.
Is Red Meat a Vital Protein Source or is it best avoided
Michael Mosley “Meat. Is it a vital source of protein and other nutrients, or would you be better off leaving it out of your diet entirely? When it comes to meat, how much is too much?
I’ve come to hear the opinions of two leading experts about the links between meat and health. They have very different points of view.
Professor Robert Pickard thinks meat plays an important part in a healthy diet.”
Professor Robert Pickard “There is no biological reason whatsoever to be unduly concerned about red meat.”
Michael Mosley “But Dr Valter Longo thinks any amount can be harmful.”
Dr Valter Longo “I think it would be safest to go to no meat at all.”
Professor Richard Pickard
Michael Mosley “So how do they come to such different conclusions? I want to hear their evidence. First up, Robert Pickard, emeritus professor of neurobiology at the University of Cardiff. He’s former Director General of the British Nutrition Foundation and a member of the Meat Advisory Panel.
What do you think about the recent article in The Lancet saying that processed meat definitely causes cancer and that red meat probably does?”
Professor Robert Pickard “It’s very important to distinguish between associations and cause and effect mechanisms. The evidence that it was based on shows associations between people that eat certain quantities of red meat and the incidence of disease, in particular, of course, cancer. But we’ve gots lots of studies to show that vegetarians have the same incidence of colorectal cancer as people that eat meat on a very regular basis. So the science would indicate that there is nothing to worry about.”
Michael Mosley “So why are there so many negative reports about red meat?”
Professor Robert Pickard “I really don’t understand that, because there is no biological reason whatsoever to be unduly concerned about red meat. I would eat red meat from pork, lamb or beef probably two or three times a week. It’s the most nutritious food that we have on our plate, and in fact, with a small amount of red meat and a tiny one-inch cube of liver, you would get all your vitamin and mineral requirements just in one portion of food. You’d only need to supplement it with a little bit of vitamin C.”
Michael Mosley “In terms of quantity, then, you are comfortable eating red meat two or three times a week? How much?”
Professor Robert Pickard “If you could take a piece of fillet steak, and you look at the palm of your hand, and if you can imagine it fitting into the palm of your hand, about a centimetre high, then that’s an appropriately moderate amount. When people ask me about beef burgers, which can be a similar shape and size, I always have to remind them that a beef burger contains 30% more fat than an equivalent weight of genuine fillet steak. So in fact, a beef burger is TOO nutritious to be eaten in large quantities by sedentary people.”
Michael Mosley “So you would put processed meat into a different category to red meat?”
Processed meat concerns affect not only weight problems but also accelerated ageing.
Professor Robert Pickard “Well, processed meat contains more fat, and that can create a problem because there is some indication that a high intake of fat could have some carcinogenic properties, and also if a meat has been preserved with nitrates or nitrites, then of course, those can be carcinogenic.”
Michael Mosley “Have you ever been tempted to become vegetarian?”
Professor Robert Pickard “No, because the biology has always been very clear to me that after the age of 60, it becomes much more difficult to absorb nutrients from the gut. So I always say to people over 60 that red meat is far more valuable to you than it was in your middle years, because now you need extra concentrations of vitamins and minerals to cope with the fact that you’re less efficient at absorbing them.”
Michael Mosley “Are your views at all affected by funding? Have you been funded by the meat industry?”
Professor Robert Pickard “No, but the Meat Advisory Panel is funded by the Agriculture and Horticultural Development Board. But my views are the views of a professional biologist, and they represent other views that professional biologists would generally have. I would not do anything that I believed to be contrary to the public interest.”
Michael Mosley “So what would your broad advice to people be?”
Professor Robert Pickard “We’ve evolved over seven million years to eat an omnivorous diet. Our gut is designed to treat both animal and plant foods. So I would maintain a pretty steady supply of animal proteins throughout life. I’d make sure that it’s slightly higher for children, and it’s particularly higher for adults over 60.”
Professor Valter Longo
Michael Mosley “So Professor Pickard thinks we all need at least some meat to stay healthy, and there is no strong evidence to link eating meat with an increased risk of cancer. Professor Valter Longo strongly disagrees. He’s Professor in Gerontology at the University of Southern California. He’s shown a link between high protein - especially from meat - and age-related diseases.
Your research suggests that too much protein is associated with accelerated ageing.”
Professor Valter Longo “Yes.”
Michael Mosley “And is there a particular level which triggers off these processes?”
Professor Valter Longo “Yes, and it turned out that people that had over 20% of their calories coming from proteins were at a much higher risk for a variety of diseases.”
Michael Mosley “But does it matter where the protein comes from?”
Professor Valter Longo “Yes, we believe that it does, and the amino acid profile of, for example, plant-based proteins is different from that of animal-based proteins. And the red meat may in fact - we don’t know yet - but may in fact have the worst profile in general, right? And we suspect that the type of amino acids that it contains has the largest effect and these growth factors that are so central for ageing and diseases.”
Michael Mosley “Now do you think there’s something particularly bad about processed meat?”
Professor Valter Longo “Yes. The processed meat may contain other components - the fat - and maybe some of the ingredients, maybe they’re based on the way the meat was processed or the way the animals were fed, and those could have additional effects that makes it even worse.”
Michael Mosley “Now you’ve said that eating large amounts of meat is as bad for you as smoking. Do you stick with that?”
Professor Valter Longo “Yes, I mean, the statement was about the risk, right? So when you look at the database of a number of diseases in the United State, following thousands of people, and you look at the risk for the group having the highest protein intake, and then you look in the same database for either smokers or past smokers, the risk increase was very similar.”
Michael Mosley “Isn’t that rather peculiar since our ancestors have been eating red meat for millions of years?”
Professor Valter Longo “Yeah, and this argument is… I always hear this and it’s completely irrelevant, and it’s irrelevant because our ancestors lived to 55, maybe, if they were lucky, they made it to 50, 55 years of age.”
Michael Mosley “So what do you eat?”
Professor Valter Longo “I eat a plant-based diet plus fish, so a pescatarian diet that is low-protein, high-nourishment and generally low-carb”
Michael Mosley “I assume that… You know, you’re obviously Italian, that in your childhood you must have eaten quite a lot of these foods.”
Professor Valter Longo “Actually, we spend a lot of time going round the world asking people what they eat now, centenarians, especially, and what they used to eat, and it turns out that when you ask centenarians, particularly Italians,they almost never ate red meat.”
Michael Mosley “Now realistically you’re not going to persuade people worldwide to give up eating meat, it’s extremely unlikely. What do you think people should do?”
Professor Valter Longo “I think that, if you can do it, as it happened for smoking, then it’s best to go down to very little or nothing. I mean, it’s interesting that we don’t use the system that we already use in a courtroom, where you have to have evidence from many different sides, right, then you put it all together and at the end, you have a verdict.”
Michael Mosley “So you think basically the verdict should be, meat, guilty?”
Professor Valter Longo “Absolutely, yes. The verdict right now is meat guilty, and then you can always appeal, and with the appeal, we will see, but I feel pretty good about the case.”
Michael Mosley “So Professor Longo is convinced that eating lots of protein, particularly from meat, is bad for us and can cause cancer.. After hearing the evidence on both sides, it’s time for me to decide on my verdict for red meat.
Now, having listened to my two experts, I am, if anything, a little bit more confused than I was. But I think something which is really clear, processed meat is bad for you. If you really want to live a long time, then probably your best bet is to go for Professor Longo’s approach, which is essentially fish and vegetables. But most of us are human. I still enjoy my steak, and so I think it’s pretty safe, if you stick to the government guidelines, which are 70 grams, on average, a day. That is not very generous, it’s a piece of meat about the size of my palm, and about one centimetre thickness.”
References
All of the above information came from the BBC series Trust Me, I’m a Doctor
