A recent study examined the effects of gamma-linolenic acid supplementation on kidney stone prevention across white and black race groups. After supplementation for 30 days, the white group showed both increases and decreases in kidney stone risk factors, while the black group remained largely unchanged.
Kidney stones are a common condition caused by the buildup of mineral deposits in the kidneys. Careful diet management is one strategy for kidney stone prevention. Phospholipids are found in red blood cells and plasma, and the fatty acid composition of these phospholipids can influence the buildup of minerals in the kidneys. For example, a high ratio of arachidonic acid to its precursor molecules is associated with an increased risk of kidney stone formation. Taking supplements of arachidonic acid precursors such as gamma-linolenic acid lowers this ratio and has been associated with a reduced risk of kidney stones.However, these effects have not been investigated across race groups with different dispositions towards the formation of kidney stones.
A research team in South Africa recently published a study in Urolithiasis investigating these effects.A total of 10 healthy white males and 10 healthy black males were recruited to participate in this pilot study. Participantsconsumedcapsules containing both linoleic acid and gamma-linolenic acid daily for a period of 30 days. After the supplementation period, dihomo-gamma-linolenic acid levels in the blood increased in the white group but not in the black group, while arachidonic acid levels did not change significantly in either group.Urine analysis provided mixed results across race groups. The excretion of oxalate, which stimulates kidney stone formation, and citrate, which inhibits it, increased in the white group after supplement use. Calcium excretion remained unchanged in both groups.
Based on the results, researchers suggest that there is potential for gamma-linolenic acid as a modest measure for kidney stone prevention, particularly among whites. However, they stress that any beneficial effects should be assessed against the risk posed by increased oxalates in the urine.With regard to the difference in response amongst race groups, the investigators postulate that it could be attributed to a reduced function of the enzyme elongase in black individuals.These results are constrained by the small sample size of the study, despite it boasting a 100% compliance rate.
This investigation has raised a number of questions on metabolic pathways in kidney stone formation and their dependence on race. Researchers hope that future studies can confirm the exact mechanism by which these race differences impact kidney stone formation.
Written By: Agustin Dominguez Iino, BSc
Rodgers AL, Jappie-Mahomed D, van Jaarsveld PJ. Different effects of γ-linolenic acid (GLA) supplementation on plasma and red blood cell phospholipid fatty acid composition and calcium oxalate kidney stone risk factors in healthy subjects from two race groups with different risk profiles pose questions about the GLA-arachidonic acid-oxaluria metabolic pathway: pilot study. Urolithiasis. 2017 Jun 16. doi: 10.1007/s00240-017-0989-7.