l-Carnosine supplementation attenuated fasting glucose, triglycerides, advanced glycation end products, and tumor necrosis factor-α levels in patients with type 2 diabetes: a double-blind placebo-controlled randomized clinical trial.

2018-01
Nutrition research (New York, N.Y.) 49
- Shiva Houjeghani
- Sorayya Kheirouri
- Esmaeil Faraji
- Mohammad Asghari Jafarabadi

PubMed: 29420997
DOI: 10.1016/j.nutres.2017.11.003

Study Design

Type: Randomized Controlled Trial (RCT)
Sample size: n = 54
Population: 54 patients with T2D
Methods: randomized, double-blind, placebo-controlled clinical trial, 2 capsules of l-carnosine 500 mg each
Blinding: Double-blind
Duration: 12 weeks
Funding: Unclear

Considering the pathologic importance of metabolic disturbances, advanced glycation end products (AGEs), and chronic inflammation in diabetes mellitus and ameliorating potentials of l-carnosine in hampering these detritions and because these effects have not been investigated in patients with type 2 diabetes (T2D) so far, we conducted the current study. We hypothesized that l-carnosine would improve glycemic control, lipid profile, AGE, soluble receptor of AGEs (sRAGE), and inflammatory markers. In a randomized, double-blind, placebo-controlled clinical trial, 54 patients with T2D were recruited and assigned into either intervention group (n=27, receiving 2 capsules of l-carnosine 500 mg each) or control group (n=27). Blood samples and dietary intakes information were collected at baseline and after 12 weeks of intervention. l-Carnosine supplementation resulted in significant decrease in fat mass and an increase in fat-free mass in the intervention group compared with the placebo group (1.5% and 1.7%, respectively) (P<.05). A significant reduction in fasting blood glucose (13.1 mg/dL); glycated hemoglobin (.6%); and serum levels of triglycerides (29.8 mg/dL), carboxymethyl lysine (91.8 ng/mL), and tumor necrosis factor-α was detected in the l-carnosine group compared with the placebo group (P<.05). In the l-carnosine group, a significant reduction in serum pentosidine levels (2.8 ng/mL) was observed compared with those at baseline (P<.05). No significant differences were observed in dietary intake, body mass index, systolic and diastolic blood pressure, fasting insulin levels, homeostasis model assessment of insulin resistance and secretion, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, sRAGE, interleukin (IL)-6, and IL-1β levels between the groups after adjusting for baseline values and covariates (P>.05). Collectively, l-carnosine lowered fasting glucose, serum levels of triglycerides, AGEs, and tumor necrosis factor-α without changing sRAGE, IL-6, and IL-1β levels in T2D patients.

Research Insights

L-Carnosine→Improved Insulin Secretion
No significant differences were observed in ... [homeostasis model assessment of] secretion ... between the groups after adjusting for baseline values and covariates (P>.05).
Effect
Neutral
Effect size
Small
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Improved Insulin Sensitivity
No significant differences were observed in ... homeostasis model assessment of insulin ... secretion
Effect
Neutral
Effect size
Small
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Increased Fat-Free Mass
increase in fat-free mass in the intervention group compared with the placebo group (1.7%)
Effect
Beneficial
Effect size
Small
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Increased HDL Cholesterol Levels
No significant differences were observed in ... high-density lipoprotein cholesterol
Effect
Neutral
Effect size
Small
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Increased Soluble Receptor of Advanced Glycation End Products
No significant differences were observed in ... soluble receptor of AGEs (sRAGE)
Effect
Neutral
Effect size
Small
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Reduced Body Fat Mass
significant decrease in fat mass ... compared with the placebo group (1.5%)
Effect
Beneficial
Effect size
Small
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Reduced Body Mass Index
No significant differences were observed in ... body mass index
Effect
Neutral
Effect size
Small
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Reduced Carboxymethyl Lysine
carboxymethyl lysine (91.8 ng/mL)
Effect
Beneficial
Effect size
Moderate
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Reduced Diastolic Blood Pressure
No significant differences were observed in ... diastolic blood pressure
Effect
Neutral
Effect size
Small
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Reduced Fasting Blood Glucose Levels
A significant reduction in fasting blood glucose (13.1 mg/dL)
Effect
Beneficial
Effect size
Moderate
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Reduced Glycated Hemoglobin
glycated hemoglobin (.6%)
Effect
Beneficial
Effect size
Moderate
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Reduced Hemoglobin A1c
A significant reduction in ... glycated hemoglobin (.6%) ... was detected in the l-carnosine group compared with the placebo group (P<.05).
Effect
Beneficial
Effect size
Moderate
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Reduced Insulin Levels
No significant differences were observed in ... fasting insulin levels
Effect
Neutral
Effect size
Small
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Reduced Interleukin-1β Level
No significant differences were observed in ... IL-1β levels between the groups after adjusting for baseline values and covariates (P>.05).
Effect
Neutral
Effect size
Small
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Reduced Interleukin-6 Levels
No significant differences were observed in ... interleukin (IL)-6
Effect
Neutral
Effect size
Small
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Reduced Low-Density Lipoprotein Level
No significant differences were observed in ... low-density lipoprotein cholesterol
Effect
Neutral
Effect size
Small
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Reduced Pentosidine Level
a significant reduction in serum pentosidine levels (2.8 ng/mL) was observed compared with those at baseline
Effect
Beneficial
Effect size
Small
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Reduced Soluble Receptor of Advanced Glycation End Product Level
No significant differences were observed in ... sRAGE ... between the groups after adjusting for baseline values and covariates (P>.05).
Effect
Neutral
Effect size
Small
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Reduced Systolic Blood Pressure
No significant differences were observed in ... systolic ... blood pressure
Effect
Neutral
Effect size
Small
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Reduced Total Cholesterol
No significant differences were observed in ... total cholesterol
Effect
Neutral
Effect size
Small
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Reduced Triglyceride Levels
serum levels of triglycerides (29.8 mg/dL)
Effect
Beneficial
Effect size
Moderate
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)
L-Carnosine→Reduced Tumor Necrosis Factor Alpha
and tumor necrosis factor-α was detected in the l-carnosine group compared with the placebo group
Effect
Beneficial
Effect size
Small
Dose
2 capsules of l-carnosine 500 mg each (1000 mg/day)