Dietary Oxysterols and β-Cell Function Among African Americans

African Americans (AAs) have a higher risk of developing type 2 diabetes than the general population. AAs are also more likely to eat foods that contain cholesterol oxides/oxysterols. Dietary oxysterols can harm the cells that produce insulin and decrease insulin production. This pilot study seeks to determine if removing dietary oxysterols with a plant-based diet will improve insulin production and decrease the risk of type 2 diabetes among AAs.

African Americans (AAs) have almost twice the incidence and prevalence of Type 2 diabetes (T2D) compared to the general population. T2D occurs when pancreatic β-cell dysfunction prevents secretion of sufficient insulin to overcome insulin resistance. While the causes of β-cell dysfunction are not fully understood, the role of cytotoxic oxidative stress is well documented. Serum oxysterols are biomarkers of oxidative stress. Oxysterols form endogenously or exogenously when cholesterol in food is exposed to light, heat, and processing. Dietary oxysterols are cytotoxic, they are absorbed and carried in the blood by lipoprotein carriers or circulate freely in serum. 7-Ketocholesterol (7-KC), the most common oxysterol in food and serum is a biomarker of cholesterol oxidation. High serum levels of 7-KC are associated with an increased risk of T2D. AAs who consume Southern dietary pattern foods such as fried and processed meats have a higher consumption of dietary oxysterols than the general population. Our central hypothesis is that the higher consumption of dietary oxysterols among AAs contributes to β-cell dysfunction and higher rates of T2D. The aim of this pilot study is to determine the effect of lowering dietary oxysterols on serum 7-KC and β-cell function among AAs with prediabetes and early T2D (HbA1c 5.7% - 7.0%). The expected outcome is that decreased exposure to dietary oxysterols will decrease serum oxysterols and β-cells oxidative stress which will improve β-cell function and glycemic control. The knowledge gained from this study may lead to improved T2D prevention and treatment strategies that may decrease the burden of T2D in all communities and eliminate the racial disparity among AAs.