Citric Acid

Citric acid is a weak organic tricarboxylic acid found in citrus fruits. Citric acid is a natural preservative and food tartness enhancer.

Citric acid induces apoptosis through the mitochondrial pathway in the human keratinocyte cell line HaCaT. It inhibits proliferation of HaCaT cells in a dose-dependent manner, but also induces apoptosis and cell cycle-arrest at the G2/M phase (before 24 h) and S phase (after 24 h)[1].

Citric acid is found in all animal tissues as an intermediary substance in oxidative metabolism. The administration of citric acid (1–2 g/kg) attenuates LPS-induced elevations in brain MDA, nitrite, TNF-α, GPx, and PON1 activity. In the liver, nitrite is decreased by 1 g/kg citric acid. Citric acid (1-2 g/kg) decreases brain lipid peroxidation and inflammation, liver damage, and DNA fragmentation[2]. Citric acid supplementation increases intestinal calcium and phosphorus absorption and the retention/intake ratio only in rats fed the 1% Ca diet. Citric acidsupplementation together with a calcium-rich diet allows to obtain an increased retention of calcium and phosphorus in bone. The prolonged administration of calcium citrate supplements may therefore help to increase bone mineral concentration[3]. Oral administration of citric acid ameliorates ketosis and protects against the development of diabetic complications in an animal model of type 1 diabetes[4].