Why Blacks are Dying from Preventable Kidney Disease

Stolen History, Stolen Health: Why Blacks are Dying from Preventable Kidney Disease

Eleven thousand African Americans die every year from chronic kidney disease only found in people of West African ancestry. Why?  It is because the gene variants that trigger these disorders are only carried by populations from the sodium-deficient interior of West Africa.  What the history books failed to reveal is that  African Americans of slave descent are not simply from West Africa.  During the era of the transatlantic slave trade, these highly skilled farmers  were kidnapped and marched more than a 1000 miles to the coast from one of the most salt-less regions in the world. Not even coastal West Africans could survive in the sweltering heat of the West African interior on a sodium intake of less than 500 mg/day. The typical American and coastal West African diet is 3400 to 5000 mg/sodium/day.  On the other hand, interior West Africans, who had never even tasted salt,  carried a remarkable genetic gift.  They possessed gene variants that were so highly absorptive and retentive of sodium that such populations could survive on the fractional amounts found in their diets merely from consuming plants and meat. They flavored their food with the ashes of millet leaves, which is high in potassium  chloride.

A Lost History

But what might be the health consequences for a population group involuntarily transported to a part of the world where they have become accustomed to consuming 1,000% more sodium than their ancestors?  The answer should be obvious but for the fact that the most vital details of our history were lost during the tumultuous era of the slave trade.  The reason American history books offer no details of the  interior regions from which our ancestors were kidnapped and enslaved is because the West African interior was in medieval times attached to the trading networks of the prosperous Islamic empires of ancient Mali, Songhay and the city-state of Timbuktu.  The 14^th century Mansa Musa of Mali was believed to be the richest man in the world because Europe obtained most of the gold for its coinage from the Muslim caravans that transported it across the Sahara and then uploaded it onto Mediterranean ships.  The source of these empires’ wealth was a rather lopsided trade in which they obtained gold mined in the region outside the boundaries of their states in exchange for rock salt brought in from the southern Saharan desert.  The inhabitants of the gold mining region were more than willing to sell their gold for rock salt, pound for pound, because that mineral was considered precious on account of its extreme scarcity in their region.  But alas, when the gold mines became depleted in the 17^th century, it was the farming populations living in the shadows of these empires that were scooped up by slave traders, marched to the Atlantic ports and uploaded onto the ships bound for America’s plantations.  Known at the time as “black gold”,  these interior West Africans were in fact the ancestors of today’s 38 million African Americans of slave descent.  In short, they were my ancestors.

An African Gene

Geneticists have identified the G1 and G2 variants of the APOL1 gene as being the cause of APOL1-Mediated Kidney Disease (AMKD), which includes a range of kidney disorders suffered by for Blacks who carry these interior West African gene variants.   It was the fact that the G1 and G2 variants were uniquely capable of allowing a person’s kidneys to function at a high level of efficiency on a minimal sodium intake.

However, lacking a detailed knowledge of African history, medical researchers made the faulty racial assumption that all Blacks have the same genetic profile.  With the imagery of slaves being uploaded onto the ships at ports along the Atlantic seacoast, scientists assumed  that slaves ingested the same amounts of salt as Africans living in the vicinity of the salt-rich ocean.  But as a consequence the medical community has to this day overlooked the most vital clue to prevention of the fatal AMKD diseases. The initial symptom in all of these disorders is salt-sensitive hypertension, that is high blood pressure triggered by a salt consumption level that is too high for the kidneys to process efficiently.

A Known Risk, But Not Advertised

In 2010, the United States Department of Agriculture and the Department of Health and Human Services identified African Americans as an at risk group for salt sensitive hypertension. They stated that this group should as a consequence reduce its sodium intake to 1500 mg/day. Sadly, this vital health advice was ignored by public health officials and the medical community at large.  It is also critical to recognize that prevention measures that are life-saving but cost-free, may not be on the top tier of the medical industry’s priority list.  Alas, we as African Americans inherited a precious gift from our West African ancestors, which were kidneys that functioned at such a high level of efficiency that they required minimum amounts of sodium.  It is time for us to assume primary responsibility for our own health and honor this ancestral gift.  We can do so by educating ourselves to ways of embracing a low-sodium lifestyle despite America’s exceptionally high-salt food culture.

Constance B. Hilliard, Ph.D., genomic historian and author of Ancestral Genomics: African American Health in the Age of Precision Medicine (Harvard University Press, 2024)