Does eating meat cause cancer and heart disease?
Except for rare cases, eating half a chicken breast a day on your salad isn’t going to give you a heart attack. In his book titled “The Whole Foods Diet,” Whole Foods CEO and Vegan advocate John Mackey acknowledges as much, admitting that getting 10% of calories from animal products is perfectly healthy for most people.
The important questions are:
- How much meat do you eat?
- Where does that meat come from?
- What type of meat is it?
In a previous post, we highlighted this Harvard Study which found that a plant based diet reduced all cause mortality in just 18 months in people suffering from a chronic illness. However, healthy members of the group showed no detriment from eating meat. The benefits of the plant based diet were found only in those who were already sick.
In light of that study, let’s repose the question.
Is eating meat one of the factors that can contribute to an increased risk for cancer and heart disease, especially in some people?
So, how can we tell if we are healthy eating the amount and type of meat in our current diet?
Simple. Get your genetics tested. Next, go to your doctor and have blood work done. The combination of genetic data and blood work will give you powerful tools for assessing whether you are consuming too much animal protein.
Below, I list the markers you’ll want to discuss with your doctor to determine whether you might be eating too much meat.
Meat eaters: know your numbers for these lab tests
LDL-P (heart health)
We spend a lot of time thinking about LDL-P at Gene Food. In fact, the fat metabolism guidelines we provide in our custom nutrition plan are aimed at helping people maintain healthy lipid numbers over a lifetime. LDL-P stands for low density liporotein particle number. You’ve probably heard of LDL before as LDL-C is known as the “bad cholesterol.” But LDL-C isn’t cholesterol at all, it’s a type of protein that carries cholesterol, and other fats, around the body.
You can think of lipoproteins as fat taxis. LDL-C measures how much cholesterol these taxis are carrying, but the cholesterol load of your LDL isn’t the whole story. In addition to cholesterol, LDL taxis also carry triglycerides. Triglycerides are a type of fat the body stores for energy. When they rise to unhealthy levels in the blood, it it is often a sign that a person is diabetic or pre-diabetic.
The LDL-P number is so important for determining heart health because it gives a picture of all the taxis on the road, both triglycerides and cholesterol, not just the LDL-C taxis.
If your LDL-P is out of range, and your triglycerides are low, it is a pretty good sign that you are eating more dietary fat than your body needs and it may be time to cut back on consumption of meat and dairy products.
Most meat has at least some saturated fat, many types of meat, like bacon and fatty cuts of steak, are loaded with saturated fat. Now, I know you’ve heard a lot of talk lately about how saturated fat is “good for you.” But who exactly is this “you” person?
If you’re a meat eater and you have an LDL-P that is under 1,000 nmol/L, great, keep doing what you’re doing.
But certain genotypes do a poor job with the saturated fat found in animal products, and some of these people should avoid meat altogether to maintain heart health.
For example, and as Aaron outlined in his post on how Bulletproof Coffee does bad things to some people’s lipids, variants in genes like PCSK9 are associated with elevated LDL, and in these cases, as with APOE4 carriers, saturated fat from all sources is risky.
People don’t absorb cholesterol in the same way and in the same amounts, and no two people have exactly the same number of LDL receptors, which are the cells responsible for removing LDL from the blood. As a result, we have very different reactions to eating saturated fat. If your LDL-P is high, especially if your triglycerides are low, it may be time to cut back on the meat.
TMAO (gut health)
We’ve already written on this blog about a gut metabolite called trimethylamine-N-oxide, or “TMAO” for short, that the New England Journal of Medicine has linked to heart disease.
The microbiome naturally produces TMAO when we eat carnitine, an amino acid found in fish and meat, and fats like choline, which is found in high amounts in egg yolks as well as certain supplements. Aaron’s post discusses how variants in a gene called FMO3 could be responsible for elevated TMAO levels in some carriers. Others have speculated that elevated TMAO levels could be the sign of a microbiome that is out of balance.
The bottom line is this: the study linking TMAO to heart disease is very credible, but it is now without its critics. For example, most of the longest lived people in the world incorporate fish in their diets. Does this mean we forget about TMAO as some would suggest?
We don’t know the FMO3 status of the people in the blue zones, and most of these populations haven’t been exposed to the assault on our microbiomes that we in the western world have to deal with as the result of products like glyphosate creeping into the food supply. The observation that people in blue zones eat fish, therefore fish must be harmless in all people, is epidemiology at its worst. It’s better to test for TMAO levels.
If they’re high, it may be a sign you’re eating too much meat.
IGF-1 (cancer risk)
Part of the reason eating meat is said to be inflammatory is because the amino acid profile in meat spikes a hormone called insulin like growth factor, or IGF-1, which our bodies need to grow muscle cells, but also to grow “bad” cells, like cancer cells. Research from Dr. Valter Longo, head of longevity at USC, has looked at how certain amino acids, such as methionine, especially when consumed in animal protein where they are most bioavailable, increase IGF-1 levels, which in turn activates a pathway in the body called mTOR, which is the cancer and aging pathway.
Unfortunately, the plant based community has done everyone a disservice in this discussion. Documentaries like What the Health, with their “zero tolerance” messaging, overplay their hand. By claiming you can never have a single bite of animal flesh ever, they undermine the scientific core of their argument, which is that we should all eat FAR LESS animal protein than we do.
The meat and cancer link is not as simple as never eat meat or you will get cancer.
Dr. Longo advocates for eating fish and certain dairy products, especially after age 65 when seniors begin to risk frailty on a completely plant based diet. In these cases, Longo recommends seniors eat fish and some goat and sheep dairy, because their IGF-1 levels can become too low.
And the little known “IGF-1” is at the heart of the meat and disease link.
So, yes, the plant based community is correct when they say that eating meat can cause, or accelerate cancer growth, but the amount of meat eaten as well as the IGF-1 levels of the person eating it play a role as well. Longo is saying IGF-1 can go too high, but it can also go too low. Your doctor can order a lab test to see where your IGF-1 levels are. If they come back high, you may want to consider eating less meat.
C-reactive protein (generalized inflammation)
As the name indicates, C reactive protein, or “CRP,” is a protein that, when elevated above 10 mg/dl in the blood, is thought to be a sign of inflammation in the body. The high sensitivity CRP (“hsCRP”) test, which, as the name suggests, is a more sensitive CRP test, is used in patients with an increased risk for heart disease. According to the Mayo Clinic, high levels of CRP can be a sign of a diverse range of conditions, ranging from chronic infection, to autoimmune conditions like Rheumatoid arthritis, to heart disease. While high CRP doesn’t necessarily mean you’re eating too much meat, Valter Longo’s research does indicate that meat consumption can have an inflammatory impact on the body and an excess of animal protein could be one of the culprits behind elevated CRP.
Eating a lot of protein can put a burden on the liver, and high CRP levels have been associated with liver cancer. (R) As I talk about in my post on the urea cycle, which is the complex system the body uses to break down the nitrogen molecules found in protein, eating protein forces the liver to process the ammonia which is produced as a waste product when we eat foods like beef, pork and chicken. The state of our urea cycle genes could decide whether protein inflames the liver, leading to elevated CRP, or whether we easily turn the ammonia into urea and excrete it out through the kidney and eventually our urine. For example, SNPs in the ARG1 gene, one of the genes that drives the urea cycle, were associated with increased CRP in Korean populations. (R
Of course, the list I offer above isn’t exhaustive. A good doctor will give you a more thorough workup than these 4 lab tests. For example, I didn’t even touch on Lp(a), but the takeaway is clear: no two people react exactly the same way to a given diet. We must individualize everything and that starts with knowing your numbers for key markers.
Are you healthy as a meat eater?
I don’t know.
What kind of meat are you eating? How was it raised? How much are you eating everyday?
Films like What the Health like to tout the ability of a plant based diet to reverse heart disease, and as the Harvard study I cite above makes clear, their claims aren’t totally lacking in merit. Plant based diets can reverse heart disease, but what the makers of the Vegan films don’t tell you is that not everyone is going to develop heart disease or cancer when they eat meat.
The issue comes down to genetics, the type of meat being consumed, and how much is consumed.
Your Grandmother may have eaten a ribeye a day and lived to be 100. But Grandma notwithstanding, you may want to think twice about that ribeye, or at least have your genetics tested, because there can be no doubt that some people are genetically much better off eating Vegan multiple days a week. However, the opposite is also true. For some, eating animal protein everyday can be part of a healthy lifestyle.
There is no easy answer.
The best course of action is to get regular blood work so you know where you stand.