Vitamins and Minerals absorption in the body

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Do you know where in the digestive system vitamins and minerals enter the bloodstream?

While different vitamins and minerals are absorbed as they pass through different areas of the digestive tract (mouth, esophagus, stomach, small and large intestine), they technically never enter the blood stream directly from the digestive system. This is because these nutrients are first absorbed from the digestive tract into the epithelial cells that line the digestive tract before they enter the blood stream. Once they have been absorbed into the epithelial cells they are no longer considered to part of the digestive system. As noted above, nutrients undergo absorption in different areas of the digestive tract. For example, some nutrients can even undergo absorption at the very beginning of the digestive tract - inside the mouth! We know that vitamins B6, B12, folate and C can be absorbed in this way, and so can the mineral zinc. (You'll find " sublingual " or " under-the-tongue " supplements in most health food stores for exactly this reason). Exactly how much vitamin and mineral absorption takes place in your mouth, however, depends on the form in which these vitamins and minerals are found in your food, how long you chew the food in question, the enzyme contents of your saliva, and other factors. In general, we get relatively little vitamin and mineral absorption in the mouth, but what we do get may be very important. There is good research in this area for supplements, and we need better research in this area for foods. After the mouth, the next potential absorption site in our digestive tract is the stomach. While some vitamin and mineral absorption may also take place directly through the wall of your stomach, this amount appears to be minor and has not traditionally been considered to be part of our vitamin and mineral absorption process. Exceptions here would be the minerals copper, iodine, fluoride, and molybdenum, which may be significantly absorbed directly from the stomach. The small intestine is by far the most important site in our digestive tract for both vitamin and mineral absorption. The small intestine is quite long (many feet in length) and virtually all vitamins and minerals can be absorbed from different areas of its surface. The part of the intestine closest to the stomach (called the duodenum) and the middle part of the small intestine (called the jejunum) specialized in absorption of most minerals. The vitamins are also spotlighted in these areas, with the exception of vitamin B12, whose primary absorption site is the very last segment of the small intestine, called the ileum. Literally hundreds of nutritive substances are absorbed from the small intestine. The last part of the digestive tract - the large intestine - is particularly important for vitamin K absorption, biotin absorption, and the electrolyte minerals (sodium, chloride, and potassium). Here is some further information from our website about the mechanisms involved with digestion and absorption of vitamins and minerals: " Vitamins and minerals are quite varied in structure and amount in the foods you eat. They can be found in food in a free form, chemically bound to a larger molecule, or tightly encased inside a food aggregate. In most cases, they are liberated during eating by the mechanical process of grinding. They may also be liberated during the breakdown of the large molecules like proteins and starch, in which they may be encased. Since your body requires specific amounts of these key nutrients, most vitamins and some minerals have active transports in place for absorption and are taken into the body in very specific ways. These active transport protein molecules act as shuttles, picking up the vitamin or mineral and taking it through the intestinal cell wall into the body, where it may be directly released or transferred to another transport molecule. Since vitamins and minerals are small and are usually found in much lower levels than amino acids, carbohydrate, and fats, these active transport protein molecules must select and pull these important molecules out of the food and take them into your body. Active transports require energy to function properly. Calcium and iron are examples of minerals that are taken into the body by active transport. Most of the water-soluble vitamins have an active transport in place as well, and these active transports are primarily found in the middle section of the small intestine, the jejunum. Some minerals, like iron and calcium, are absorbed in the first part of the small intestine as well as the jejunum. The fat-soluble vitamins (vitamins A, D, K, and E), as discussed above, are absorbed with fat micelles, and therefore require fat to be present for their full absorption. Magnesium is a mineral of tremendous importance for bone health, energy production, and overall healthy functioning throughout the body since it activates more than 300 cellular enzymes. Like calcium, magnesium must be constantly supplied to maintain optimal function. Magnesium doesn't have an active transport, but depends entirely on dietary intake and a healthy intestinal lining for its absorption, and can be absorbed throughout the entire small intestine and even in the colon. Low intakes of magnesium, or loss of ability of the intestinal tract to absorb magnesium due to intestinal inflammation or disease, can result in a variety of problems such as muscle twitching or tremors, weakness, irritability and restlessness, depression, and weak bones. Magnesium is found at highest levels in whole foods such as grains but is often removed during processing. Whole grain bread and cereals will have a much higher amount of magnesium than white bread, which is made from refined flour. Vitamin B12 is also absorbed differently from the other vitamins and minerals. First, it is most commonly found attached to proteins, and therefore requires protein breakdown to be liberated. Then, it requires a protein made in the stomach, called intrinsic factor, for its absorption, but is not absorbed until the vitamin B12-intrinsic factor complex reaches the final part of the small intestine, the ileum. Optimal digestion of vitamin B12 is dependent on your ability to make a healthy amount of stomach acid, since protein breakdown requires stomach acid and research has shown that intrinsic factor is also not secreted in adequate levels when stomach acid is low. "