Early humans were adapted to a high potassium diet consisting of foods high in potassium and low in sodium. Although the specific diet varied greatly depending on the location of the tribe, a high potassium to sodium ratio was present in all the diets. We discussed here that prehistoric groups closer to the equator ate food that was higher in plants than those farther from the equator. Also, those in coastal areas differed from those located inland. Despite the differences in the specific foods eaten, a high potassium to sodium ratio was present in each group.
Modern Indigenous Diets Are High Potassium Diets
Modern indigenous peoples have a high potassium diet. Throughout the world those who have had little change in their diet also show a high potassium to sodium ratio. Specifically, those with a ratio over 5 have virtually no prevalence of hypertension. But those who changed their diet to a more modern one have a lower ratio. And they have an prevalence of hypertension proportional to the lowering of the ratio.
One example of an unchanged diet is the diet of the Tarahumara Indians of Mexico before 1979 (1). They had an prevalence of hypertension of less than one percent. And their diet had a very high potassium to sodium ratio. This diet had little meat, and included a great deal of corn and beans. Additionally, the Indians were very physically active and were lean. One of their favorite games was a kickball game in which they ran as much as 200 miles in several days.
And there are other indigenous peoples throughout the world that until the 1960s had had very little change in their diet. This included the Aita of the Solomon Islands, the Yanamamo Indians of Brazil, the natives of Botswana and Kenya, the Eskimos, and the Cuna Indians of Panama. In particular, they all had a low incidence of hypertension. And they all had a diet of high potassium foods.
Change From Traditional Diets Leads To Hypertension
However, this has been changing in the past few decades. It is especially evident in Africa, where the prevalence of hypertension has been rising rapidly. Many tribes living traditionally as their ancestors have been losing members to urban centers. Furthermore, the traditional diets of these members have been shifting to a more modern diet as more and more people move into the city.
In the 1960s the blood pressure of the Bushmen was studied in their traditional rural setting (2). This blood pressure was compared to Bushmen who were no longer in the traditional setting. The average blood pressure of the rural Bushmen was approximately 108/66. However, their more urban counterparts had a higher blood pressure at 122/71.
Also, the increasing percentage of people with hypertension as people age in Western society was absent. There was no change in blood pressure with age in the rural Bushmen. In fact, those over 60 years of age had the same average blood pressure as those 18 to 35 years of age.
Sub-Saharan Africa
Today hypertension is affecting a rapidly increasing percentage of the population of sub-Saharan Africa, as they move into the city and adopt a more Western diet. A recent study (3) contrasts the blood pressure in rural and urban areas of Namibia, Tanzania, Kenya, and Nigeria. The more urban populations have higher systolic and diastolic pressures than those who have remained in rural areas.
Similarly, several longitudinal studies were done in Kenya in the 1980s. They indicate the increasing sodium and decreasing potassium in the diet as the rural population moves into the city. One such study (4) was done of the Luo of Kenya. The rural members had a lower blood pressure than the more urban members. Going along with this was a greater potassium to sodium ratio in the diet of the rural members than in the diet of the more urban members.
Change In The Tarahumara Diet Leads To Hypertension
Although the changes in diet in sub-Saharan Africa are not controlled experiments in dietary change, and the changes will vary from person to person, a controlled experiment was done with the Tarahumara of Mexico (5). A group of Tarahumara was put on a hypercaloric Western type diet for 5 weeks. Although potassium and sodium were not specifically studied, the foods listed had a higher sodium content than the traditional diet. And the Tarahumara's blood studies showed marked changes. Specifically, the blood lipids went from a very favorable profile to a much more unfavorable profile.
More recently, two studies of the Tarahumara show the deterioration that has occurred since their traditional diet has become Westernized. A study (6) of the Tarahumara children in boarding schools shows a major shift in the potassium to sodium ratio from the ratio of the original diet discussed above. And a 2012 study (7) of Tarahumara adults shows a marked increase in obesity and hypertension among the modern Tarahumara. From an incidence of hypertension of less than 1%, hypertension is now found in 28% of adults.
Genetics?
Overall, the evidence from the more contemporary peoples living a life that is similar to their ancestors shows a diet with a higher potassium to sodium ratio than the modern diet. Claims that their low blood pressure is due to their different genetics don't hold up, since each group develops hypertension when placed in an urban setting with a Western diet.
In summary, multiple studies of dietary change, as individuals from rural indigenous groups of people change lifestyles, show that hypertension rises as the potassium to sodium ratio in their diet falls. These studies are further evidence of the value of a high potassium to sodium ratio in the daily diet.
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1. The food and nutrient intakes of the Tarahumara Indians of Mexico. Cerqueira MT, Fry MM, Connor WE. Am J Clin Nutr. 1979 Apr;32(4):905-15.
2. Blood pressure in Bushmen of the Kalahari Desert. Kaminer B, Lutz WP. Circulation. 1960 Aug;22:289-95.
3. Hypertension in sub-Saharan Africa: cross-sectional surveys in four rural and urban communities. Hendriks ME, Wit FW, Roos MT, et al. PLoS One. 2012;7(3):e32638. doi: 10.1371/journal.pone.0032638. Epub 2012 Mar 12.
4. Blood pressure and associated factors in a rural Kenyan community. Poulter N, Khaw KT, Hopwood BE, et al. Hypertension. 1984 Nov-Dec;6(6 Pt 1):810-3.
5. Changes in lipid and lipoprotein levels and body weight in Tarahumara Indians after consumption of an affluent diet. McMurry MP, Cerqueira MT, Connor SL, Connor WE. N Engl J Med. 1991 Dec 12;325(24):1704-8.
6. [Adequacy of the diet served to Tarahumara children in indigenous boarding schools of northern Mexico]. Monárrez-Espino J, Béjar-Lío GI, Vázquez-Mendoza G. Salud Publica Mex. 2010 Jan-Feb;52(1):23-9. [Article in Spanish]
7. Physical activity, cardio-respiratory fitness, and metabolic traits in rural Mexican Tarahumara. Christensen DL, Alcalá-Sánchez I, Leal-Berumen I, Conchas-Ramirez M, Brage S. Am J Hum Biol. 2012 Jul-Aug;24(4):558-61. doi: 10.1002/ajhb.22239. Epub 2012 Feb 5.
