It seems that every year, a study comes out proving once and for all that red meat is the cause of heart disease, cancer, diabetes, and every malady known to man. People seem to want red meat to be unhealthy. This bias bleeds into the research as well. Studies on red meat and its effects on our health are often conducted with what are called epidemiological studies. They look at making associations between causes and effects in population. To be clear association does not equal cause. Often these are based on asking people what they ate in a day in the form of food surveys. These methods have since been under fire, because people generally can’t recall what they ate in a day. Also, when looking at dietary and other habits within a lifestyle, it is difficult to separate what is causing what.
For instance, in this review, researchers tried to adjust for unhealthy lifestyle habits like smoking and having a higher BMI. What they didn’t adjust for was the junk food being eating with meat. Check out what other foods were associated with meat intake.
“Meat intake can be associated to obesity due to its richness in fats or included in dietary patterns rich in processed foods, fries, and refined carbohydrates (especially processed meat).”
That sounds about right. A diet rich in fast food is being described here. Processed carbohydrates, simple sugars, high heat cooking, vegetable oils, and low quality/processed meat. If red meat is generally consumed with other foods like the ones above, things like cancer, obesity, and diabetes will ensue. I wouldn’t be so quick to jump on meat though. We have been consuming meat for millions of years, and just found out its bad for us? What we have chosen to consume with red meat is bad for us. Lets dive into a few common misconceptions.
1. “Red Meat Promotes Heart Disease”
This is a common utterance I hear when people see what I eat, or when I am explaining what I eat. ” But what about your heart!”. The truth is that red meat does not adversely effect heart function. In a review of 24 different studies, it was found that consuming fresh red meat showed no increase in cardiovascular disease. From the review.
“Our results indicate that the consumption of ≥0.5 servings of total red meat/d does not influence these clinically relevant and commonly measured modifiable CVD risk factors”.
This review lumped all red meats together, including processed. A neutral effect on heart health was still observed. Only the higher ranges of meat intake, 3 or more servings a day, was a change in cholesterol observed. HDL (good cholesterol) was raised in healthy amounts.
Another factor we formerly thought was associated with CVD(cardiovascular disease), is a compound called TMAO, the end product of carnitine (found in red meat) metabolism in our gut. TMAO has been associated with CVD in rodents, and was thought to have the same effect in humans. Humans and mice are very different beasts, and a study was done showing this. From the study.
” In a cohort of adults, aged 33 to 45, plasma TMAO concentration was not associated with CAC incidence or progression over 10 years of follow‐up, after accounting for an extensive set of potential confounders. Nor was TMAO associated with other measures of CVD risk, including cIMT, insulin resistance, inflammatory markers, and lipids. “
TMAO was also not associated with other commonly lumped together conditions like chronic inflammation (potential cause of metabolic disease like cancer), insulin resistance (precursor to type-2 diabetes), and unhealthy levels of cholesterol.
2. “Red Meat Causes Cancer”
There are two main types of meat. Processed, and un-processed. They are two completely different types of foods with different types of compounds within them. There are also different ways to cook meat, which elicit different compounds from it. Burning it to a crisp, just like burning vegetables to a crisp, elicits carcinogenic compounds.
The problem with blaming all problems on meat, is that people on a meat heavy diet are often making other poor health choices. They smoke more, drink more, move less, and eat more proccessed foods. Most people who chose to try to be health conscious eat less meat, less processed foods, smoke less, and exercise more. Practices like excercise, smoking less, and eating less processed food lead to better overall health and less inflammation, i.e. less cancer occurrence. Many of these studies acknowledge that they are not factoring for these lifestyle habits when asking who eats meat or not. If someone is eating red meat within a primal aligned diet, where exercise is prioritized, oxidized vegetable oils aren’t consumed, and processed food is not consumed, red meat is a nutrient dense source of fats, protein, vitamins, and minerals.
We have all seen the WHO study that places processed meat as a group 1 carcinogen (same category as tobacco, alcohol, and arsenic), and unprocessed meat as a group 2 carcinogen. Scary stuff, at first glance. Even if we ignore the shoddy science, poor surveying of food, and look past lifestyle factors, and just look at the findings at face value, they have been blown WAY out of proportion. According to the WHO findings, there are an extra 3 cases of colorectal cancer “from consuming meat” for every 100,000 adults. That is literally nothing compared to smoking, which they put in the same classification.
Other researchers have conducted studies and reviews looking to see if there is conclusive evidence for meat causing cancer. This review looked at 35 studies for conclusive evidence. From the review.
“Collectively, associations between red meat consumption and colorectal cancer are generally weak in magnitude, with most relative risks below 1.50 and not statistically significant, and there is a lack of a clear dose-response trend.”
This is basically saying that there is no risk. Everything that we eat and do carries a certain set of risks or stressors, and red meat does not stand out among anything else. in some studies, intake of meat was actually inversely associated with CVD and cancer occurrence. From a study on Asian men and women.
“Red meat intake was inversely associated with CVD mortality in men and with cancer mortality in women in Asian countries”.
The people that ate the most red meat had LESS cancer.
This is the other “cause” of cancer that advocates for less or no meat bring up. Every time. IGF-1 (insulin-like growth factor) is built similarly to insulin. It is a compound released when we eat animal protein, and it is vital. Children need it to grow into adults, and adults need it for cell division. We need it to build muscle and keep it on our bodies. Just like any process in the body, it is a nuanced issue that is not good or bad. The argument for limiting its activation at all costs is that it can allow certain cancers like prostate and breast to grow more when already present, if IGF-1 is high.
The important thing to realize is that it does not cause cancer. Associations do not prove cause. Here is the kicker…. low IGF-1 was associated with cancer as well as high IGF-1. Also heart disease. Also all cause mortality. From a meta-analysis of studies ,
“Both low and high IGF-I increased all-cause, CVD, and cancer mortality, whereas only low IGFBP-3 is associated with mortality.”
The main takeaway is that IGF-1, like any process in the body, is more nuanced than eating meat=IGF-1=cancer. The benefits from eating some grass-fed meat and living a healthy lifestyle with plenty of movement far outweigh the actual risk of cancer or heart disease from IGF-1. We need it, so don’t be afraid of it.
3. “But Red Meat Makes Your Body Acidic!”
Here is another urban legend that’s been around for a while, and the one I see the least science behind. Somehow, it has been propagated by many people as the cure to all disease. The two biggies I hear about are cancer and osteoporosis. Firstly, lets get it out of the way that the food you eat does not affect your body pH.
There are different areas in the body with different pH. Our stomach for instance, is around 2 to 3.5. This is highly acidic and necessary to break down food. Our blood is always around 7.35 to 7.45. The claim behind all of this is called the acid-ash hypothesis. The main point is that after foods are metabolized, they leave behind acid or alkaline ash. This is true. But fear not, like I said before our bodies are not stupid. Our kidneys and lungs get rid of the ash byproducts of what we eat whether they are alkaline or acidic. A quote from Dr. Chris Kressner.
“While more reasonable than the first claim, the acid-ash hypothesis seems to completely disregard the vital role the kidneys play in regulating body pH. The kidneys are well equipped to deal with ‘acid ash.’ When we digest things like protein, the acids produced are quickly buffered by bicarbonate ions in the blood. (7) This reaction produces carbon dioxide, which is exhaled through the lungs, and salts, which are excreted by the kidneys. During the process of excretion, the kidneys produce ‘new’ bicarbonate ions, which are returned to the blood to replace the bicarbonate that was initially used to buffer the acid. This creates a sustainable cycle in which the body is able to maintain the pH of the blood, with no involvement from the bones whatsoever.”
The reason he brings up bones at the end is that many proponents suggest osteoporosis is caused by bicarbonate being leached from our bones to counter acidic ash. Our kidneys actually generate bicarbonate to keep the blood at an alkaline pH. Many alkaline dieters test their pH through urine, thinking that this proves their body is in an optimal alkaline state. Testing our pH through urine only shows what our kidneys are excreting after a meal. This is either acid or alkaline based on what we ate. It has nothing to do with our net body pH. It is dangerous to promote an alkaline diet to battle such serious diseases as cancer. There is literally no evidence to support this claim. Also, your bones will be fine.
Red meat has been a part of our diet going back to hunter gatherer traditions spanning back 2.6 million years. Our bodies know what to do with it. What it doesn’t know how to deal with are factors like sedentary lifestyle, excess sugar and refined carbohydrate consumption, processed foods, drinking and smoking too much, and artificial light pollution. Why don’t we start looking at those factors instead of a food we evolved to eat?
Comment below on what your think!