Answer to Question 1
Vitamin E is a fat-soluble antioxidant and one of the body's primary defenders against the adverse effects of free radicals. Its main action is to stop the chain reaction of free radicals from producing more free radicals. In doing so, vitamin E protects the vulnerable components of the cells and their membranes from destruction. Most notably, vitamin E prevents the oxidation of the polyunsaturated fatty acids, but it protects other lipids and related compounds (for example, vitamin A) as well.
Accumulating evidence suggests that vitamin E may reduce the risk of heart disease by protecting low-density lipoproteins (LDL) against oxidation and reducing inflammation. The oxidation of LDL and inflammation have been implicated as key factors in the development of heart disease.
Answer to Question 2
Like vitamin D, vitamin K can be obtained both from foods and from a nonfood source. Bacteria in the GI tract synthesize vitamin K, although the amount is insufficient to meet the body's needs and its bioavailability is limited. Therefore the diet must also supply vitamin K, which is found primarily in leafy green vegetables such as spinach and kale, fruits such as avocado and kiwi, and some vegetable oils such as soy-bean oil. Naturally occurring vitamin K in foods is phylloquinone (sometimes called vitamin K1), whereas vitamin K produced by GI bacteria is menaquinone (sometimes called vitamin K2).
Metabolism of vitamin B12
Pathway for vitamin D activation.
Selected Drugs for Osteoporosis and Other Bone Disorders
IgG after treatment with pepsin.
Describe how fat is digested, absorbed, and transported in the body
Liver Functions