In parts one and two of this series, I presented a “glimpse” of the Maasai, first of their way of life as it existed in a particular village in the 1970s, and then of their diet as it existed at the turn of the twentieth century. Now it’s time to turn to what we can say more generally about the Maasai across time and space, taking a look both at the things that stay the same and the things that vary from place to place and change with time.
Before we do that, however, I’d like to take a brief moment to reiterate why I am even bothering with so many facets of Maasai culture when my ultimate goal is to answer the question of just how free of heart disease they really were when George Mann and Bruce Taylor documented this apparent immunity, and what it is that explains this immunity. The short answer is two-fold. On the one hand, although we often invoke the Maasai to argue that eating animal fat must not be the cause of heart disease (a point with which I wholeheartedly agree), their freedom from heart disease may result from factors that have nothing to do with diet, such as their sleeping patterns, spirituality, division of labor, ecology, or exercise habits. On the other hand, their culture and its dynamic flux through the course of history has deeply affected the composition of their diet, how that diet has changed over time, how that diet is distributed within their population, and some of the gross discrepancies between the popular perceptions that outsiders have of their diet and what they actually eat. I’ll elaborate this “short answer” with a few illustrative examples below.
It’s Not Just About Diet!
And We Die From Many More Causes Than Heart Disease…
When George Mann examined four hundred Maasai men for electrocardiogram (ECG) evidence of existing heart disease in the summer of 1962, he and his research team considered it “noteworthy that there were few aged men.” More precisely, they only found three men over the age of 55 (1). If we were to analyze Mann’s research results in a historical vacuum and through a firmly entrenched dietary myopia, as if anything and everything he discovered about them was some sort of eternal truth about the Maasai as a people and the effects of their fat-rich or even mythologically plant-free diet, we might rush to the conclusion that Maasai men necessarily lived nasty, brutish, and short lives precisely because they ate a lot of animal fat.
The truth is quite different. Mann’s discoveries pertained to certain Maasai men at a particular time and in a particular place, and whether we can generalize these discoveries to the Maasai as a whole requires knowing something about their history, like whether the number of long-lived elders tended to stay the same over time or tended to rise and fall sporadically, and it requires knowing something about whether those elders typically died from dietary causes like choking on animal fat, or from other causes like being eaten by lions or starving to death during sporadic famines.
As Mann’s group wrote in its report, “an extensive drought followed by disastrous floods occurred in parts of East Africa in 1961.” They claimed it must not have affected the Tanzanian Maasai they studied, or that if it did its effects had clearly subsided by the summer of 1962, based on a single piece of evidence: they found no increase in skin-fold thickness between their initial measurements in 1962 and their additional measurements in 1963, which they took “at the end of a rainy season when the grass was lush and the milk flow copious.” Had the effects of the famine persisted through the summer of 1962, the men they studied would have been piling on the body fat during these lush times to recover what they had lost during the famine. While this argument might suffice to claim that the Maasai men who survived the famine had fully recovered by the summer of 1962, it hardly suggests that those who had died in 1961 had come back to life! Indeed, there are records of prominent Maasai men being reincarnated as black pythons (2), but no records of them returning in their original human form, replete with the very same ECG patterns they had possessed before their resurrection.
We are thus left with a number of questions that I’ll address in this series as we move on, like whether this famine did indeed affect the Tanzanian Maasai, whether it may have affected Mann’s or Taylor’s results by killing off the eldest Maasai in the greatest numbers, or killing off those most vulnerable to heart disease rather than killing at random, and whether there is anything we can say more generally about whether and how often Maasai men and women in times past lived truly long lives.
Heart Disease Is About More Than Diet
I’ve written before about how conflating the lipid hypothesis with the diet-heart hypothesis led to the wrongful public condemnation of animal fat. Conflating these two hypotheses also makes it impossible to appreciate the position of someone like George Mann, a staunch opponent of the diet-heart hypothesis while a definite supporter of the lipid hypothesis. Despite their inability to find many “aged men” numbered among the living, Mann and his research team nevertheless examined over two hundred Maasai men who had surpassed the age of thirty for ECG evidence of heart disease (1), and 21 hearts and aortas of deceased Maasai who had lived past the age of fifty, including eight who had lived past the age of sixty (3), for autopsy evidence of heart disease. These numbers were sufficient for them to make age-adjusted comparisons with the American population, and they concluded that the Maasai possessed an immunity to heart disease that Americans did not. Mann, for his part, was convinced that they owed their immunity at least in part to their incredibly low levels of blood cholesterol.
When it came to the diet-heart hypothesis, Mann’s criticism of Ancel Keys was not that he had fudged his data but that he had interpreted it with great naïveté (4). When it came to the lipid hypothesis, however, Mann’s criticism of Keys was simply that he had brought “too little” evidence “too late” to support a hypothesis about which there was already “no doubt” (5):
There is no doubt that the risk of clinical CHD [coronary heart disease] is related to the level of serum cholesterol. This was shown by Gofman et al. (9), Dawber et al. (10) and Doyle et al. (11) and the evidence has been succinctly summarized by Cornfield (12). The meager data of Keys et al. (13) collected from 281 self-selected business men have been both too little and too late.
Even in his obituary for the diet-heart hypothesis, “Diet-Heart: End of an Era” (4), Mann noted that “where societies are developed, the cholesteremia is higher, and the atherosclerosis is more xanthomatous, more obstructive,” and pronounced his confidence that the “evidence indicates that the prevailing hypercholesteremia is contributory and that a major reduction would make a difference in clinical events.” In that paper he suggested that excess vitamin D from food fortification, trans fats from hydrogenated vegetable oils, or environmental carbon monoxide might be the culprits in developed societies, poisoning the ability of our bodies to convert cholesterol to bile acids. Our question for now, however, is what, in the mind of Mann, offered protection to the Maasai.
Mann offered several hypotheses to explain this protection. Some of them were dietary hypotheses. He showed, for example, that yogurt consumption suppresses the synthesis of cholesterol and suggested that the fermented milk drunk by the Maasai contains a microbial byproduct that has a similar effect on cholesterol synthesis as the now-ubiquitous statins (6). He also suggested that the young male warriors had even lower cholesterol than the rest of the Maasai because they avoided “some noxious dietary agent for a time,” one that might have been hiding in the “processed staples” made from “flour, sugar, confections and shortenings” that were available “through the Indian dukas scattered about Masailand” (3).
On the other hand, he thought their high level of physical activity also made an important contribution by increasing the size of the blood vessel lumen (3) and perhaps in other ways as well (7). The exercise hypothesis, of course, is one that we can only evaluate competently if we understand something about the Maasai lifestyle. There is no doubt, moreover, that the division of labor by age and sex in Maasai society and the way governments have increasingly marginalized their traditional way of life over the last century makes the question much more complex than whether the Maasai as a people are active or sedentary. Thus, we arrive at the need to understand both the culture and the history of the Maasai.
And then there is Bruce Taylor, Mann’s arch-nemesis, at least with respect to the Maasai. Taylor’s group insisted that the Maasai were protected by genetics. This argument hinged in large part on their contention that the Maasai “have intermingled little with other tribes and have maintained their racial purity” (8). One could see the evidence of purity simply by casting one’s gaze upon them:
Their striking physical characteristics — tall, slender bodies, long faces, slightly slanted eyes, narrow noses, thinner lips and slightly lighter skin than the average Bantu — make them easily recognizable.
Mann’s group wasn’t buying it (3):
Taylor et al. (24) have repeatedly discussed their belief that the Masai immunity to CHD and hypercholesteremia is genetically determined. For at least 10,000 years the main occupation of Masai warriors has been raiding the neighboring tribes for cattle and women. Their success is evidenced by their huge herds and the variety of Masai physical appearances. They range in size and color far more than their neighbor. Casual observers mistake the Masai dress and manner for uniformity of physique. The Masai are one of the most genetically mixed groups in East Africa. The genetic argument is worthless.
Ya hear that?! Taylor wasn’t looking at the Maasai — he was looking at their clothes!
Clearly making heads or tails of such a debate requires knowing a little something about Maasai history.
And then there is José Day’s group, who showed that urbanized Maasai had higher blood pressure than tribal Maasai (9). These authors suggested this was “due to psychological factors, such as increased stress and anxiety, associated with the change in lifestyle.” They claimed that in the tribal situation “all decisions are taken at a group collective level,” whereas “those who have left the tribal situation . . . take on full personal responsibility for their lives, their survival and that of their families” and “the nature of their employment” means they have “to keep regular hours, carry out orders from superiors, etc. and that they ” are “personally responsible for the success or otherwise of their careers.” They also quoted a book on hypertension by GW Pickering:
Is the change from primitive tribe to Western-style life dietetic, sanitary, or in peace of mind? As Ostfeld and Shekelle (1967) pointed out, the ritual of the tribe probably brings peace of mind to those who observe it.
So now we arrive at yet more questions about Maasai culture, such as how collectivist or individualist it is, what types of stress and anxiety it produces, and whether its ritual life (or perhaps the faith and spirituality lying behind it?) provides its own protection. Again and again we see that much more than diet may be at play.
Diet, Meet Culture. Culture, Meet History.
Food is obviously part of culture, and we have already seen so far in this series that foods are distributed differently by age and sex and are closely tied to religious ritual in Maasai life. The Maasai diet has evolved over time as famines have come and gone and as nation-states have have left their mark. Some authors have suggested, for example, that the number of plant species used by the Maasai has declined from over five hundred at the turn of the twentieth century to less than three hundred in the current century because of the legacy left by the 1925 “Witchcraft Act” that outlawed traditional medicine in Kenya for several decades, and because of increasing modernization on a variety of fronts (11). Our view of the Maasai diet, moreover, has often been colored by the points people have been trying to prove.
Although Taylor’s group conducted chemical analyses Maasai milk (8), neither his group nor Mann’s collected any detailed information about the other foods the Maasai ate. Mann’s descriptions of the Maasai diet were conveniently chamelionic, changing colors to suit whichever argument he was making. For example, his group admitted quite straightforwardly that it was among the “warrior class that the animal fat intake is high” because the warrior is “bound by tribal tradition to a diet of milk and meat,” but what was the diet like for the rest of the Maasai? When Mann and his colleagues wanted to explain why “lesions of the mouth, tongue, and teeth were most common among the elders after age 35,” they suggested it was because of “their adoption of a vegetable diet” (1). On the other hand, when they wanted to show that “Masai women do not show hypercholesteremia during the third trimester of pregnancy despite their customary diet which is rich in animal fat and protein,” they described the diet in a very different light. Despite stating that the women consumed even more plant foods than the men, “especially maize and squash,” Mann’s group claimed that the diets of the women, like those of the men, “also are predominantly milk and meat” (10).
At other times, the Maasai as a whole were “carnivores,” as we see here (1):
The Masai do not use salt. Their language contains no word for salt. Whereas their vegetarian neighbors and their cattle crave salt, these carnivores seem to obtain sufficient salt from the flesh and milk which they eat.
One has to wonder how it is that the Maasai never developed a word for salt if the vegetarian cattle they tend crave it. When the father teaches the son how to herd cattle, does he say nothing about bringing them to salt licks? If the Maasai have no word for salt, how did they communicate the cravings of their cattle to Mann and his research team?
According to Moritz Merker, who lived among the Maasai for eight years around the turn of the twentieth century (described in part 2 of this series), the Maasai word for steppe salt is e munján, which they added to their sweet potatoes and beans, and the Maasai word for natron salt is e magát, which they added to their chewing tobacco. Of course it is always possible that Merker had thought he was talking to true Maasai when he was actually talking to their vegetarian cattle, much as the Taylor group had thought they were gazing upon the “slender bodies, long faces, slightly slanted eyes, narrow noses, thinner lips and slightly lighter [than Bantu] skin” of the Maasai but were instead just gazing upon their clothing.
Arguments over the Maasai diet extend beyond the nutritional world. As an example, Dorothy Hodgson uses Merker’s description of the trade that Maasai women engaged in to obtain those sweet potatoes and beans we discussed above to argue that “women’s former freedom to travel, their economic autonomy, and their opportunities to congregate with one another were curtailed as they were relegated to the increasingly isolated and subordinate confines of the ‘domestic’ domain” (2). Paul Spencer disputes her claim that Maasai women had much more power in former times, and argues not simply that it was only older women chaperoned by men who participated in this trade, which was largely initiated by the outside groups rather than by the Maasai women themselves, but beyond this that these active trade networks were a result of the devastating cattle epidemics that occurred shortly before Merker lived among them, in the 1880s and 1890s, and thus cannot be said to represent the overall historical situation (12). So it is not just nutritional arguments served by grasping at often biased and highly uncertain reconstructions of the Maasai diet, but arguments about the historical role of women as well.
As this series unfolds, then, I hope to shed enough light on Maasai culture and history to create an honest reconstruction of their age-structure and diet, acknowledge the uncertainties in each, and determine just what we can and cannot say about Maasai freedom from heart disease and its likely causes.
Read more about the author, Chris Masterjohn, PhD, here.
1. Mann GV, Shaffer RD, Anderson RS, Sandstead HH. Cardiovascular Disease in the Masai. J Atheroscler Res. 1964;4:289-312.
2. Hodgson DL. The Church of Women: Gendered Encounters Between Maasai and Missionaries. Bloomington, IN: Indiana University Press. 2005; p. 31 on black pythons; p. 13 on economic trade.
3. Mann GV, Spoerry A, Gray M, Jarashow D. Atherosclerosis in the Masai. Am J Epidemiol. 1972;95(1):26-37.
4. Mann GV. Diet-Heart: end of an era. N Engl J Med. 1977;297(12):644-50.
5. Mann GV. Interpretation of human measurements. Am J Clin Nutr. 1967;20(9):1040-2.
6. Mann GV. A factor in yogurt which lowers cholesteremia in man. Atherosclerosis. 1977;26(3):355-40.
7. Mann GV, Garrett HL, Farhi A, Murray H, Billings FT. Exercise to prevent coronary heart disease. An experimental study of the effects of training on risk factors for coronary disease in men. Am J Med. 1969;46(1):12-27.
8. Ho KJ, Biss K, Mikkelson B, Lewis LA, Taylor CB. The Masai of East Africa: some unique biological characteristics. Arch Pathol. 1971;91(5):387-410.
9. Day J, Bailey A, Robinson D. Biological variations associated with change in lifestyle among the pastoral and nomadic tribes of East Africa. Ann Hum Biol. 1979;6(1):29-39.
10. Mann GV, Shaffer RD. Cholesteremia in pregnant Masai women. JAMA. 196;197(13):1071-3.
11. Bussmann RW, Gilbreath GG, Solio J, Lutura M, Lutuluo R, Kunguru K, Wood N, Mathenge SG. Plant use of the Maasai of Sekenani Valley, Maasai Mara, Kenya. J Ethnobiol Ethnomed. 2006;2:22.
12. Spencer P. Time, Space, and the Unknown: Maasai Configurations of Power and Providence. London and New York: Routledge. 2003; p. 227-8.🖨️ Print post
Perhaps you could comment on this:
Chris Masterjohn says
Thanks Chuck. That is actually cited in this post, and I will discuss it further towards the end of the series.
Imran Chaudhary says
Thanks for this great series. Could you post a link to where you discuss further the study Chuck references? I can’t find it!
And the plot thickens…
Alice C. Linsley says
I added this as “related reading” here:
Keep up the good work. This is fascinating research.
sara r. says
This is all really facinating! Thanks so much for all of your work and explanations. I found your blog a few days ago and I’ve been devouring it. The statistics kind of make my brain hurt, but in a good way!