Ketogenic diet (KD) is characterized by high fat, very low carbohydrate, and moderate protein intake, leading to a state of ketosis. Although commonly employed for weight management and therapeutic purposes, its potential impacts on hepatic and renal function remain a subject of debate. This study evaluated the effects of different dietary fat sources in a high fat KD coconut oil, olive oil, and butter on liver enzymes, renal markers, and body weight in albino Wistar rats.

Forty rats were acclimatized for two weeks under standard laboratory conditions with appropriate ventilation, a 12-hour light dark cycle, and constant temperature, following the National Research Council’s Guide for the Care and Use of Laboratory Animals (NRC, 2011). The animals were then randomly assigned to four groups (n = 10). Group A (control) received standard rat chow, while Groups B, C, and D were fed a 65% high fat KD formulated with butter, coconut oil, or olive oil, respectively, for eight weeks. Body weights were recorded weekly. At the end of the experiment, 24-hour urine samples were collected in metabolic cages. Blood was obtained via cardiac puncture under chloroform anesthesia, and serum was separated by centrifugation. Liver function was assessed by determining aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and total protein, albumin, and globulin levels. Renal function was evaluated through serum and urinary urea, creatinine, and urinary albumin. Data were analyzed by ANOVA, with significance accepted at P < 0.05.

KD feeding significantly reduced body weight compared with control (P ≤ 0.05). Hepatic enzyme activities increased markedly, particularly in coconut oil fed rats. AST levels were 160.1 ± 9.5 U/L (control), 143.4 ± 8.2 U/L (butter), 196.1 ± 3.9 U/L (olive oil), and 260.1 ± 17.8 U/L (coconut oil). ALT increased from 36.0 ± 3.9 U/L (control) to 91.2 ± 18.7 U/L (coconut oil). ALP increased from 9.90 ± 0.74 U/L (control) to 24.9 ± 2.5 U/L (butter). Total protein and albumin levels decreased significantly (P = 0.0032), while globulin remained unchanged.

Renal markers showed no deterioration. Serum urea decreased from 64.20 ± 3.41 g/dl (control) to 39.40 ± 4.70 g/dl (butter), 29.90 ± 1.46 g/dl (coconut oil), and 40.20 ± 2.62 g/dl (olive oil). Serum creatinine fell from 1.42 ± 0.04 mg/dl to 1.05 ± 0.09 mg/dl (butter), 0.85 ± 0.07 mg/dl (coconut oil), and 1.03 ± 0.07 mg/dl (olive oil). Urinary albumin declined from 0.22 ± 0.03 g/dl to 0.19 ± 0.02 g/dl (butter), 0.15 ± 0.02 g/dl (coconut oil), and 0.13 ± 0.01 g/dl (olive oil). Urinary creatinine was 3.84 ± 1.02 mg/dl (control), 3.84 ± 0.90 mg/dl (butter), 1.75 ± 0.46 mg/dl (coconut oil), and 4.31 ± 0.70 mg/dl (olive oil). Albumin:creatinine ratio decreased from 120.6 ± 32.0 to 94.6 ± 23.0 (butter), 174.7 ± 61.8 (coconut oil), and 41.3 ± 8.3 (olive oil).

In conclusion, high fat ketogenic diets induced hepatocellular stress, particularly with coconut oil, but did not compromise renal function. Olive oil based KD exhibited the most favorable hepatic and renal profiles.