Cardiovascular disease is the no.1 leading cause of death in large parts of the world, especially in industrialized countries, where disorders of the circulatory system claim a staggering number of lives ever year. It’s sad to say, but chances are you or someone you love will eventually succumb to ischemic heart disease, stroke, or some other type of cardiovascular disorder.
If you’d been a hunter-gatherer or traditional horticulturalist living in a natural environment, however, it’s highly unlikely that such conditions would have caused you much heartache – if any at all. In such an alternate reality, you’d likely be in the presence of a number of exceptionally supple and healthy hearts and arteries.
Current standards based on evolutionarily atypical norms may be misleading
When a researcher or doctor undertakes the task of assessing an individual’s cardiovascular condition in a detailed manner, he or she will have to draw blood from the subject’s body, and proceed to have that blood analyzed. The levels of various well-established cardiovascular biomarkers, such as blood pressure, LDL cholesterol, and CRP, would then be compared to established standards as to what constitutes a normal, desirable, and undesirable niveau for each of the analyzed compounds, something that allows for a characterization of the subject’s cardiovascular condition.
This sounds like a reasonable way of doing things, right? It’s certainly a fairly straight-forward, yet productive, procedure. There’s arguably a problem with it though. This snag isn’t inherent to the procedure itself; rather, it’s been transmitted from way that we humans tend to view the world. We tend to accept the status quo with respects to what we see around us as the norm, frequently forgetting that the situation we observe merely constitutes a tiny “blip” in the history of the world.
In the context of health and medicine, we typically create standards and classification systems based on data that have been accumulated from examinations of contemporary human populations belonging to the modern civilization, often forgetting that the characteristics of such populations are very much atypical from an evolutionary point of view. The norms within such populations are most certainly going to deviate substantially from the evolutionary norms for our species. In other words, a measurement or observation that we consider to be normal or desirable based on investigations of “civilized” societies likely doesn’t match the true norm or ideal for Homo sapiens.
The hunter-gatherer standard
The things mentioned above are very much relevant to the discussion about cardiovascular health, in the sense that there’s a gap between typical “hunter-gatherers levels” of cardiovascular biomarkers and the levels that are common of people living in manufactured environments. Among other things, the former generally have markedly lower blood pressure than the latter and a very different blood lipid structure, featuring lower triglyceride and LDL levels, among other things.
As I see it, it’s this profile that we should turn to when we set out to determine what constitutes the norm or optimum for our species. Such a profile may certainly be difficult for the average Joe and Jen to obtain; however, that doesn’t mean that we should just ignore it and proceed to create something that’s easier to attain, but that’s not scientifically accurate. As I see it, it’s better to face and try to deal with the truth, which is that even the cardiovascular profile of westerners who are considered to be healthy by today’s standard likely isn’t ideal.
The notion that the cardiovascular health of hunter-gatherers and non-westernized, traditional people is generally superior to that of other populations is supported by a number of scientific findings. For example, in 2017, a group of researchers looking into the physical activity levels and cardiovascular health of the Hadza hunter-gatherers found that…
Biomarkers of cardiovascular risk [for the Hadza hunter-gatherers] including blood pressure and cholesterol levels fall below clinically relevant risk thresholds, and, in general, suggest good cardiovascular health across the lifespan compared with populations in the United States (1).
This is particularly relevant to discussions about what constitutes normal cardiovascular functioning, as the Hadza occupy a part of the world in which much of early human evolution I thought to have taken place.
Many other hunter-gatherer tribes seem to be equally well of, as highlighted by this quote.
Among past and contemporary hunter-gatherers, CVD [Cardiovascular Disease] and T2DM [Type-2 Diabetes Mellitus] risk factors like obesity, hypertension, hypercholesterolemia and insulin resistance appear to be rare. Epidemiological surveys from the mid-20th century among! Kung hunter-gatherers, Central African pygmies, Australian aborigines, South African Bantu, Pacific Islanders and other rural, subsistence-level populations with minimal exposure to market economies support the notion that these risk factors are rare, and suggest that changes in diet, physical activity, other behaviors (e.g. smoking, alcohol consumption) and psychosocial stress alters the health of such populations in ways predicted by the mismatch hypothesis. (2)
The bottom line is that cardiovascular disease really isn’t an issue for hunter-gatherers. At least not a major one. This makes perfect sense from a Darwinian point of view, seeing as hunter-gatherers depend on good cardiovascular functioning in order to effectively conduct some of the affairs that they need to conduct in order to survive and reproduce.
Why are we worse off than hunter-gatherers in the cardiovascular department?
The aforementioned studies clearly show that hunter-gatherers, as well as certain other traditional, non-westernized groups, are in a league above other humans with respects to their cardiovascular health. They don’t tell us exactly why that is though. However, based on the information we have at hand regarding nutrition and health and the workings of the human body, we can make some educated guesses….
- We’re not as physically active as they are
This is probably the number one reason why we’re at a level below hunter-gatherers with respects to cardiovascular health. We’re simple not as active as they are, and hence, we don’t provide our cardiovascular systems with the stimuli that they are designed to require in order to function at their best.
- We take in a lot more salt than they do
It’s well-established that the average salt intake of hunter-gatherers is extremely low when compared with the average intake in industrialized societies, and that a high salt intake is a major risk factor for hypertension and heart disease.
- We live longer than they do (on average)
Hunter-gatherers frequently live into their 60s and 70s (3); however, they are not as long-lived as the populations of some affluent nations, in part because they don’t have access to any form of modern medicine. Seeing as a person’s risk of developing diseases such as heart disease increases with age, this helps explain the higher rates of cardiovascular disease in industrialized parts of the world.
- We take in more saturated fat than they do
Contrary to popular belief, hunter-gatherers don’t take in a lot of saturated fat. They obviously derive some saturated lipids from the food they eat, in particular from the animals they take down; however, their intake of this group of fatty acids is lower than that of the typical westerner. This is relevant to discussions about cardiovascular health, as a high saturated fat intake is – despite what some people claim – is a risk factor for cardiovascular disease.
- Our microbiotas aren’t as diverse or resilient
Over the most recent decade, it has becomes increasingly clear that microbes greatly contribute to shaping the workings of our cardiovascular systems, partly via their impact on immune-related parameters (2 , 4). Genome-microbiome discordance goes hand in hand with inflammation, which in turn sets the stage for cardiovascular illness.
Note: This list is by no means exhaustive; however, I believe it highlights some of the key reasons why we’re generally worse off than hunter-gatherers in the cardiovascular department.
By studying the workings of the cardiovascular systems of hunter-gatherers, we may get a sense of what constitutes the norm or ideal for our species with respects to cardiorespiratory fitness, cholesterol levels, blood pressure, and the like. Studies have revealed that hunter-gatherers set the bar high, in the sense that their cardiovascular profile is generally greatly superior to that of people who live in areas of the world where traditional human customs have largely been abandoned in favor of modern, technologically advanced alternatives. By adjusting our diet and lifestyle on the basis of Darwinian insights, we may regain some of the cardiovascular robustness that we’ve lost.