Influence of Diet Behavior on Insulin Resistance in Hypertensive Black Sub-Saharan Africans: A Multicentric, Cross-Sectional Study

Background: Insulin resistance (IR) is the backbone of cardiovascular diseases (CVDs). The latter are the most common non-communicable diseases globally. Diet is an important determinant of CVDs. The link between diet and cardiovascular health could be explained by an association between diet pattern and IR. Aims: To investigate the association between salt and specific food consumption as well as different diet patterns (Mediterranean, westernized, and intermediate dietary patterns) with HOMAIR as a surrogate marker of IR, and fasting insulin in Black, sub-Saharan essential hypertensive patients. Methods: The multicentric, cross-sectional analysis involved 77 Congolese Black hypertensive participants with no history of cardiovascular disease. Daily sodium chloride intake (NaCl g/24h) was estimated from 24-hour urine collection. Dietary behaviours were evaluated through a semi-quantitative food frequency questionnaire (FFQ). Homeostatic model assessment of insulin resistance (HOMAIR) ≥ 2.5 was used as surrogate marker of IR. Results: A decrease in weekly consumption of fruits, vegetables and fish would significantly explain an increase of 29% (r = 0.292;p = 0.010), 24% (r = 0.242;p = 0.034) and 23% (r = 0.226;p = 0.048) of the value of HOMAIR respectively. In contrast, an increase in daily sodium chloride intake was associated with 28% (r = 0.283, p = 0.027) of the increase in HOMAIR. Also, a decrease in the average weekly consumption of fruit, vegetables and fish would significantly explain an increase of 25% (r = 0.247;p = 0.030), 30% (r = 0.302;p = 0.008) and 31% (r = 0.313;p = 0.006) of fasting insulin. In contrast, an increase in red meat consumption was associated with a 26% increase (r = 0.257, p = 0.024) in fasting insulin. In multivariable adjusted analysis 45% of variation in fasting insulin (R2 = 0.452;overall p = 0.005) were explained by fruits, vegetables and fish consumption. 38% of variation in HOMAIR (R2 = 0.379;overall p = 0.047) were explained by fruits and vegetable consumption and daily sodium chloride intake (NaCl g/24h). Conclusions: In hypertensive Black sub-Saharan Africans, Salt intake and westernized diet seem to promote insulin resistance whereas Mediterranean diet, fruits, vegetables and fish consumption enhance insulin sensitivity.