How are vitamins and minerals absorbed?
Vitamins and Minerals are often lumped together when discussing proper nutrition, with many plans including "a multi-vitamin" (usually including essential minerals) with no explanation about how this affects eating habits. Vitamins and minerals are different substances, and they affect the body in different ways.
Vitamins are organic compounds that are obtained from diet instead of being synthesized by the body, and precluding minerals, amino acids, and fatty acids. The only vitamin the body can create is Vitamin D, which is generated in the skin through absorption of ultraviolet radiation from the Sun. Vitamins are found in every organic food, and are absorbed in the digestive system through the stomach and intestinal linings. Some vitamins are water-soluble -- they dissolve in water, are absorbed into the bloodstream, and the excess is filtered through the kidneys and excreted in urine -- while others are fat-soluble -- they are absorbed in the intestines via Lipids, and because they are not filtered, they can store up quickly and become toxic to the body.
Dietary Minerals are inorganic chemical elements -- not compounds -- which are needed to maintain good health. Many of these are found in organic foods: milk contains calcium, eggs contain sulfur, and spinach contains iron. Dietary minerals tend to be water-soluble, so they dissolve in water, absorb through the stomach and intestinal linings, enter the bloodstream, and are filtered through the kidneys. Because they are inorganic, minerals can cause damage in large quantities; for example, excess calcium can create kidney stones from particulate buildup. Minerals are generally available in the correct quantities in normal food, and do not need to be supplemented in healthy adults.