The Krebs cycle is the central engine of cellular energy metabolism. It's where your body gets most of its energy from food. If you are low in any of these B vitamins, Simplifying the B Complex: How Vitamins B6 and B9 Modulate One Carbon Metabolism in Cancer and Beyond 10.4: Riboflavin Medicine LibreTexts Elemental Selenium and Vitamin B2 (riboflavin) are essential for glutathione use and recycling. Selenium is really low in Australian soils, and people are commonly deficient. Signs of low B2 are blood