If you have gut issues and also react PHENOMENALLY to fat-soluble vitamins, then most likely you need to make fixing bile metabolism your N1 priority. This is far more common than you might think and fat-soluble vitamins are essential for our health. Let's take vitamin K as an example. Vitamin K refers to: -K1 (phylloquinone) and -K2 (menaquinones) found throughout the body in organs like the liver, brain, heart, pancreas, and bones. These vitamins are vital for activating proteins that regulate blood clotting, bone mineralization, and tissue health, protecting these systems from dysfunction and disease. K1 is primarily used by the liver to activate clotting factors. However, its bioavailability from plant sources is limited, with absorption rates as low as 5–15% from vegetables, even with added fat. K2 is synthesized by animals from K1 or by bacteria during fermentation. It’s preferentially used by non-liver tissues for functions like bone and cardiovascular health. Now, in general, vitamin K: -Activates proteins like prothrombin and protein S, which are essential for blood clotting and tissue protection. Prothrombin ensures proper clot formation to prevent excessive bleeding, while protein S, found in the liver and pancreas, supports tissue integrity and immune function. -Prevents arterial calcification by activating MGP, which inhibits calcium crystal formation in blood vessels with some studies showing that higher K2 intake was associated with a 52% lower risk of aortic calcification and a 41% lower risk of coronary heart disease. -Is critical for brain health, with high concentrations in myelinated regions where it supports sphingolipid synthesis. Sphingolipids, like sulfatides, decline with age and are up to 93% lower in early Alzheimer’s disease. K2 also activates Gas6, promoting neuron survival and Schwann cell migration, which supports nerve repair and neuromuscular junction formation. -Is a regulator of calcium metabolism through its activation of osteocalcin and matrix Gla protein (MGP). Osteocalcin binds calcium to form strong bones and teeth, while MGP prevents calcium from depositing in soft tissues like arteries. Some studies show that K2 supplementation reduces vertebral fractures by 60% and hip fractures by 80% in osteoporosis patients and low K2 levels lead to inactive osteocalcin, increasing fracture risk by over five times. -Promotes testosterone synthesis, with studies showing MK-4 supplementation doubling testosterone levels in male rats. -Inhibits abnormal cell growth and calcium deposition in the prostate and kidneys (by activating Gas6 and other proteins) -Is abundant in testes, where it activates proteins like Gas6, which regulates apoptosis and supports sperm function. -Improves insulin receptor sensitivity and supports insulin-producing beta cells in the pancreas. Note 1: Vitamins A and D instruct cells to produce proteins like osteocalcin and MGP, but K2’s carboxylation process enables these proteins to bind calcium, ensuring proper function. Note 2: Statins reduce vitamin K levels by inhibiting its recycling. Note 3: It can be found in natto, hard and soft cheeses (hard ones have more), goose liver and grass fed butter. And this is just ONE of the fat soluble vitamins and the rest of them are extremely crucial for our well being.