A lot of people, including some health professionals and scientists, seem to operate under the belief that cancer is an (almost) inevitable part of the human life cycle. This isn’t surprising, seeing as cancer is today a leading cause of morbidity and mortality in many parts of the world. In industrialized nations in particular it’s so normal for old people to get cancer that malignant cell growth is often thought of as being a natural part of the human ageing process. Not only that, but certain cancers have recently been on the rise among younger generations.
What’s frequently forgotten is that this situation doesn’t represent the evolutionary norm for our species. Throughout the vast majority of the time our species has been around, all humans lived in a wild, natural environment. This begs the question: Do hunter-gatherers and other traditional groups of people who live under non-industrialized conditions get cancer?
Cancer incidence in traditional societies
We know more about the incidence of cardiovascular diseases and metabolic disorders among traditional populations than about the incidence of cancer. That said, the latter issue is not unexplored. Over the years, I’ve read a great number of books and scientific papers that cover topics related to evolutionary health. In many of these publications, cancer isn’t mentioned; however, in some, it is.
All of the evidence I’ve seen suggests that the incidence of cancer is very low among hunter-gatherers and traditional, non-westernized people (1, 2, 3, 4, 5, 6). This is true for a number of cancers, including colon and breast cancer, two of the leading cancers in developed nations. I’ve even heard it be said that some indigenous people don’t have a word for the diseases that we know as cancer. They don’t need one.
Here’s what medical doctor Giacinto Libertini had to say about this matter in a 2013 review paper:
It is worth noting that, in Ache people in wild conditions, the main causes of death for modern western populations (heart attacks, diabetes, hypertension, etc.) are absent. Moreover, cases of death by cancer are not reported, although, in the group “adult aged 60+ years”, some deaths attributed generically to unspecified causes or to “old age” could be the result of neoplastic diseases. In any case, the data indicate that neoplastic diseases were rare events in Ache people in the forest period. This rarity of cancer in primitive conditions is not a new thing and is confirmed elsewhere.
For example, some anecdotal, but authoritative, information about the immunity from cancer of primitive populations are reported by Price: Dr. J. Romig, “a surgeon (of Anchorage) of great skill and with an experience among the Eskimos and the Indians, both the primitives and the modernized … stated that in his thirty-six years of contact with these people he had never seen a case of malignant disease among the truly primitive Eskimos and Indians, although it frequently occurs when they become modernized” (p. 83).
Dr. J. R. Nimmo, the government physician in charge for Torres Strait Islands people told Dr. Price that: “in his thirteen years with them he had not seen a single case of malignancy, and seen only one that he had suspected might be malignancy among the entire four thousand native populations. He stated that during this same period he had operated on several dozen malignancies for the white populations, which numbers about three hundred” (p. 179). (1)
It’s certainly possible that the incidence of cancer among traditional people is underreported. Irrespective of whether this is the case or not, there’s no doubt that the incidence is much lower than among westernized humans. There’s also no doubt that domesticated animals used in industrial food production are more susceptible to develop cancer than animals living in their native habitat.
Why is the incidence of cancer much lower among hunter-gatherers than among people who live in an industrialized environment?
Could the reason why cancer isn’t as big of a threat to hunter-gatherers as it is to modern office workers simply be that hunter-gatherers typically don’t live as long as desk jockeys? Well… I don’t find that to be a completely satisfactory explanation. Many hunter-gatherers grow into their 60s and 70s (7), and from what I’ve read, cancer is not just rare among young hunter-gatherers, but also among old ones. There’s not a whole lot of research in this area; however, there is some. The written accounts of explorers and travelers I’ve seen, as well as the available scientific research, indicate that far fewer old, traditional people than old, westernized people experience years of disability and pain as a result of cancer.
This isn’t really surprising, seeing as cancer compromises organismal fitness. This is clearly true in cases where cancer develops early in life; however, it also to some extent applies to cases that involve cancer morbidity late in life. An old, sick person is obviously less capable of caring for closely genetically related individuals (e.g., children, grandchildren) than an old, healthy person. Not only that, but an old, sick person needs to be cared for by others (e.g., their children), who may suffer, fitness wise, as a result of the time and energy they put into that care. This is particularly relevant when talking about people who live in a natural environment, in which food is not abundantly available and nobody has access to modern medical care.
Another possible explanation for why the incidence of cancer is so much lower in hunter-gatherer societies than in industrialized countries is that infant mortality is higher in the former than in the latter. In other words, it’s possible that “weak” individuals that would potentially have gone on to develop cancer sometime during their lives die before the cancer process gets started. That could partly explain why fewer traditional than non-traditional people develop cancer; however, again, I don’t find it to be a completely satisfactory explanation. I find it unlikely that the incidence of cancer would have been markedly higher among Paleolithic humans if infant mortality rates had been lower.
The only logical conclusion I can come to is that the primary (but not sole) reason why cancer is rare among traditional, non-westernized populations is that traditional people, in particular hunter-gatherers, aren’t subjected to persistent noxious stimuli brought about by evolutionary mismatches. In contrast to the typical westerner, the typical hunter-gatherer eats a very healthy diet, exercises regularly, and is lean and fit.
Moreover, perhaps more importantly, the typical hunter-gatherer is not chronically inflamed. This is important with respects to cancer, seeing as the immune system helps protect the body against malignant cell growth (8). Cancer risk is greatly elevated by chronic inflammation and aberrant immunoregulation (8, 9, 10, 11).
The bottom line
The incidence, prevalence, and distribution of cancer among traditional, non-westernized populations have never been studied in a systematic manner. That said, a fairly substantial amount of data has been generated through small, independent studies and explorations. This data clearly indicate that the incidence of cancer is much higher in industrialized countries than in non-westernized, traditional societies. There are many reasons as to why this is, the chief one being that we’re genetically much better suited to live in a natural, Paleolithic-type environment than in a modern, industrialized one.