Updated: Mar 15
People have been scientifically looking at blood since the 1600’s when the first blood transfusion are said to have been done. But advanced blood testing was not developed until the 1900’s, and it really came along after the push for blood lipid testing in the 1950’s. Since then we humans have been testing more and more things in the blood, we can look at everything from blood born pathogens, to red blood cell counts and characteristics, and levels of certain vitamins and minerals. Blood testing has become one of the hallmark ways that doctors assess health and investigate disease. However, I would argue that while blood testing can be useful, it may not be the best thing to focus on when it comes to assessing if we are healthy or not.
Humans have been around for a long time, at least 300,000 years. Yet, blood testing has only become prevalent in the last 100 years or so. If we look at finding normal ranges of certain blood markers we have to take into account that we have only established “normal ranges” of blood markers for people living in the modern day. We have to acknowledge that we have no idea what the normal ranges for blood work would have been for the very first humans that evolved, or the hunting and gathering humans that roamed the Earth for 280,000 years, or the first farmers.
Let’s put what we do have in perspective. Let’s say we take an animal out of the wild and placed it in a similar but still not natural habitat, fed it unnatural food, and placed it in an unnatural social environment than what it had in the wild. After leaving it in that unnatural environment for a while, we then we decide to take blood work on this animal and determine what it’s normal ranges are. Do we think that the levels of blood markers on the animal in this unnatural environment would be what is normal for it? I don’t. Yet, this is essentially what we have done with humans.
There is evidence that early modern humans were high level carnivores and even more carnivorous that other known carnivores of the time. (1) There is also evidence for hunting and a large die off of large mammals during the time of the first modern humans. (2) This lifestyle was likely the way of life until about 10-12,000 years ago when humans started farming and living in cities. So, for nearly 280,000 years humans were living in nature, in small social groups, with little exposure to toxins, and eating lots of meat and animal fat. Unfortunately, we have no idea what the blood work of those humans would have looked like. If we did, I think that this blood work would give us a better idea of the numbers we should be aiming for.
Since blood testing has only been around for the last 100 years or so, then we only know what modern-day humans blood work looks like. I think finding normal ranges in a population like this and then obsessing over keeping everything within the normal ranges is a bit short-sighted. This is not to say that there are not things that we can see on blood work that tell us when major problems are happening and intervention should be done, the issue arises more when someone is experiencing excellent health, or makes a lifestyle change that gives them better health, yet some of the blood work numbers go out of the “normal ranges”. Should we stick to the conventional wisdom and attempt to correct these numbers, or should we reflect on the observation that the health of the person is increasing yet some health markers get “worse”. The question becomes which observation is false, the health the person is experiencing or the out of range number on the blood test?
I am more inclined to go with the blood test being a false indicator of health. After all, if a person is experiencing better health and a blood marker goes out of range, maybe that is where that number needs to be for that person to have health. The opposite is true as well as I know many people who have become frustrated with health challenges and symptoms yet they are told nothing is wrong with them because their testing comes back normal. I get messages all the time from people who change their diet in a certain way and experience vast improvements in health but are freaking out because certain numbers on their blood work go “out of range”. This is especially true when people move towards the ancestrally appropriate animal-based diet that humans ate for most of their time as humans. Let’s look at some examples of the more common ones.
The first is blood sugar. While most people on animal-based diets experience good blood sugars that stay stable some people develop slightly elevated, but stable, blood sugars. Given that research has shown that big fluctuations in blood sugar are what drives damage and that higher but stable blood sugar did not cause damage, (3) I think this observation is okay on an animal-based diet.
Next is white blood cells, some people on an animal-based diet have lower white blood cells. White blood cells help us batter inflammation and infection. I feel that the reason for this is two-fold. One is that these diets tend to result in very low inflammation, the second is that cholesterol can bind and neutralize pathogens (4) and therefore less white blood cells are needed.
Next, we have some kidney tests like blood urea nitrogen (BUN) and creatinine. These are known to be slightly elevated on high protein diets. However, this is not an indicator of the kidney struggling, it is just what we see on high protein diets. The fear from this comes from the false idea that high protein damages the kidney. This has been shown to be false in multiple studies. (5) I would argue that the slight elevation in BUN and creatinine may actually be what is normal for humans given we at high animal protein for thousands of years before we started farming.
Then there are liver enzymes. While most people on animal-based diets see normal levels with these, sometimes people see slight elevations in liver enzymes. Elevated liver enzymes show if there is stress on the liver, but what we eat is not the only thing that can stress the liver. A toxin overload can do this, which is while alcohol is so damaging to the liver. Also, if someone has done recent intense exercise this can slightly elevate liver enzymes for up to a week after. Given that many people who try animal-based diets are into health and likely also do intense exercise, this is a common occurrence.
Next is morning cortisol. Cortisol is our stress hormone and it always spikes in the morning to wake us up. Some people on an animal-based diet see a higher spike than others. Given that a huge problem in society is feeling sluggish in the mornings and taking a while to get going, I would argue that in these people the “normal” spike in morning cortisol may not be doing what it is supposed to. People on animal-based diets tend to report no issues waking up in the morning so maybe this slightly higher spike is a good thing. Curiously, cortisol has been shown to slightly elevate blood sugar, (6) so maybe this effect is also what is driving the elevated but stable blood sugar we see in some on animal-based diets.
The last is everyone’s favorite, cholesterol. While the other tests we discussed only see light elevations, some people see huge jumps in their total and LDL cholesterol on ketogenic or animal-based diets. This happens because the body starts making ketones and the process of making ketones is similar to the one for making cholesterol, therefore we get more cholesterol by default. Also, plant fats compete for absorption with animal fats in the intestines. If we eliminate plants fats and eat only animal fats we get much more animal fat, cholesterol, absorption. I have written a lot in previous blogs on the benefits of higher cholesterol like immune defense, energy delivery, delivery of fat-soluble vitamins, cell repair, making hormones, and preventing atherosclerosis. There are clear benefits to having cholesterol around and higher levels have been shown to not have a negative effect on lifespan (7) or cause heart disease. (8)
The craziest thing is that the “normal ranges” for LDL cholesterol have been changed over the years. At first it was supposed to be no higher than 250, then they lowered it to 200, then 150, then 100, now they say it needs to be under 100. To me this means two things; the first is that we have no idea what “normal” is for this number and “normal” is being changed haphazardly, and the second is that “normal” is being heavily influenced by drug companies who profit from doctors using LDL lowering drugs.
The take home is that we have determined what is “normal” on blood work out of the context of what is a normal environment for humans. Therefore, we should not freak as much when we achieve higher level of health by putting ourselves back into an environment more like our natural one and then see “out of range” numbers in blood work. I see blood work like I see western medicine. Western medicine is great for an emergency situation, it will save your life in times of life-threatening infection, traumas, and general medical emergency, but it is proving to be terrible for fighting chronic disease. Blood is the same way, if some serious imbalance is happening in your body then blood work can be an excellent way to detect and find out how to correct it. But trying to tell if we are healthy or not by micromanaging our blood work is not a good approach to achieving health, it may even have a negative effect when people obsess of their blood work and try to over correct things which leads to high levels of anxiety.
Overall, I think blood work for the sake of determining if we are healthy is a false idea. Like I said, it is really only good for telling us if something is drastically wrong. To think that we can take a snapshot of one component of our body (blood) at one single moment and be able to tell what is going on in the whole complex biological ecosystem that is our body is wishful thinking. I will also take blood work into account and do so with all my patients and clients, but humans have become one of the most dominant species on Earth by listening to their bodies and doing what made them feel strongest so they could pass on their genes and ensure the survival of the species. This time tested, engrained test of trying something new and seeing if we feel better, perform better, or improve in any way can be a powerful tool in our quest to achieve health. Letting a test undermine how we actually feel about our health can be a mistake.
But consult with your physician before making any changes based on, or not based on, bloodwork. 😉
Stay healthy out there!
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