Sulfur-Containing Amino Acids and Lipid Metabolism
JOURNAL OF NUTRITION
Authors: Blachier, Francois; Andriamihaja, Mireille; Blais, Anne
Abstract
The metabolism of methionine and cysteine in the body tissues determines the concentrations of several metabolites with various biologic activities, including homocysteine, hydrogen sulfide (H2S), taurine, and glutathione. Hyperhomocysteinemia, which is correlated with lower HDL cholesterol in blood in volunteers and animal models, has been associated with an increased risk for cardiovascular diseases. In humans, the relation between methionine intake and hyperhomocysteinemia is dependent on vitamin status (vitamins B-6 and B-12 and folic acid) and on the supply of other amino acids. However, lowering homocysteinemia by itself is not sufficient for decreasing the risk of cardiovascular disease progression. Other compounds related to methionine metabolism have recently been identified as being involved in the risk of atherosclerosis and steatohepatitis. Indeed, the metabolism of sulfur amino acids has an impact on phosphatidylcholine (PC) metabolism, and anomalies in PC synthesis due to global hypomethylation have been associated with disturbances of lipid metabolism. In addition, impairment of H2S synthesis from cysteine favors atherosclerosis and steatosis in animal models. The effects of taurine on lipid metabolism appear heterogeneous depending on the populations of volunteers studied. A decrease in the concentration of intracellular glutathione, a tripeptide involved in redox homeostasis, is implicated in the etiology of cardiovascular diseases and steatosis. Last, supplementation with betaine, a compound that allows remethylation of homocysteine to methionine, decreases basal and methionine-stimulated homocysteinemia; however, it adversely increases plasma total and LDL cholesterol. The study of these metabolites may help determine the range of optimal and safe intakes of methionine and cysteine in dietary proteins and supplements. The amino acid requirement for protein synthesis in different situations and for optimal production of intracellular compounds involved in the regulation of lipid metabolism also needs to be considered for dietary attenuation of atherosclerosis and steatosis risk.
Dietary inflammatory index score, glucose control and cardiovascular risk factors profile in people with type 2 diabetes
INTERNATIONAL JOURNAL OF FOOD SCIENCES AND NUTRITION
Authors: Vitale, Marilena; Calabrese, Ilaria; Massimino, Elena; Shivappa, Nitin; Hebert, James R.; Auciello, Stefania; Grioni, Sara; Krogh, Vittorio; Sartore, Giovanni; Signorini, Stefano; Rivellese, Angela A.; Riccardi, Gabriele; Vaccaro, Olga; Masulli, Maria
Abstract
We examined the relationships between the dietary inflammatory index (DII(R)), dietary habits and cardiovascular risk factor profiles in people with type 2 diabetes mellitus (T2DM). Energy-adjusted DII (E-DII (TM)) scores were calculated from a Food Frequency Questionnaire in 2568 T2DM patients from different parts of Italy. Analyses were conducted according to quartiles of sex-specific E-DII scores. Higher, more pro-inflammatory, (quartile 4) E-DII scores were associated with overall poor quality of the diet characterised by higher content of refined carbohydrates, added sugars, saturated fat and cholesterol and lower unsaturated fat, fibre and polyphenols compared to quartile 1. Higher E-DII scores also were associated with higher waist circumference (105.4 vs. 103.5 cm;p = 0.002), triglycerides (154.6 vs. 146.1 mg/dL;p = 0.005), diastolic blood pressure (80.05 vs. 78.6 mmHg;p = 0.04) and lower HDL-cholesterol (45.3 vs. 47.4 mg/dL;p = 0.04). In conclusion, E-DII is a potent marker of overall quality of the diet and is associated with an unfavourable cardiovascular risk factor profile.