are essential compounds needed by the body to grow and develop normally and to contribute to a healthy life. They are classified as either water-soluble or fat-soluble and each vitamin has multiple functions. Water soluble means the vitamins are easily dissolved in water, while fat-soluble means they are absorbed through the intestinal tract with the help of lipid (fats.) Generally, water-soluble vitamins are readily excreted from the body. There are 13 vitamins found in the human body: four that are fat-soluble (vitamins A, D, E and K) and nine water-soluble (8 B vitamins and vitamin C). The best and preferred way to get enough vitamins is to eat a balanced diet. Also, your body produces its own vitamins D and K. However, in some cases, taking a vitamin supplement may be required for optimal health. Until the 1800s, vitamins were solely obtained through foods, but changes in diet over the years altered the types and amounts of vitamins ingested by most people. Vitamins produced in the form of pills have been available for several decades and allow supplementation to the daily diet. It is advised that you discuss taking vitamin supplements with your family physician, especially if you have any medical conditions or take prescription medications.
The metabolic functions of Vitamin A in the body include vision, gene transcription, immune function, embryonic development and reproduction, bone metabolism, skin health and antioxidant activity. Vitamin A can be found in many foods, such as liver, carrots, spinach, sweet potatoes, kale and other leafy vegetables, broccoli, peas, pumpkin, cantaloupe melon, eggs, apricots and mango.
Vitamin D plays an important role in the maintenance of the organ systems. It also regulates the calcium and phosphorus levels in the blood by promoting their absorption from food in the intestines and by promoting re-absorption of calcium in the kidneys. Vitamin D promotes bone formation and is essential in the development of a strong skeleton. A deficiency in Vitamin D can result from inadequate intake coupled with inadequate sunlight. Many people are Vitamin D deficient, especially those who live in northern climates where sunlight is limited. Natural sources of Vitamin D include fish liver oils, fatty fish such as herring, salmon and tuna, mushrooms, and eggs.
Vitamin E is the collective name for eight different tocopherols and tocotrienols, which are fat-soluble vitamins with antioxidant properties. Of these eight, a-tocopherol has been studied the most and has the highest bioavailability, with the body preferentially absorbing and using this form. It is claimed that a-tocopherol is the most important lipid-soluble antioxidant as it protects cell membranes from oxidation by reacting with lipid radicals produced in the lipid per oxidation chain reaction. This removes the free radical intermediates and prevents oxidation reaction from continuing. The functions of other forms of Vitamin E have been less studied. The following foods are high in Vitamin E: nuts, olives, avocado, asparagus, seeds, green leafy vegetables, wheat germ and vegetables oils such as corn, sunflower and soybean oils.
Vitamin K comes from the German word "koagulation." Coagulation refers to the process of blood clot formation and Vitamin K is essential for the functioning of several proteins involved in blood clotting. There are two naturally occurring forms of vitamin K. It is found primarily in dark green leafy vegetables such as spinach, kale, cabbage, broccoli and Brussels sprouts. Some fruits are also high in Vitamin K, including avocado and kiwi.
The B vitamins consists of eight water-soluble vitamins that play important roles in cell metabolism. The eight B vitamins work together to boost metabolism, enhance the immune system and nervous system, help keep skin and muscles healthy, encourage cell growth and division and other benefits. Supplements containing all eight are usually referred to as Vitamin B complex, but supplements for individual B vitamins are also available. The B vitamins are: B1, also known as thiamine, B2 or riboflavin, B3, also known as niacin, B5 or Pantothenic Acid, B6 or pryridoxine, B7 also known as Biotin, B9 or Folic Acid, and B12, also known as Cobalamin or Cyanocobalamin. Brewer’s yeast has one of the highest levels of B vitamins. Other good sources include turkey, tuna, liver and liver oil, potatoes, bananas, lentils and tempeh. Vitamin
B12 is not available from plant products and therefore it is a dietary concern for vegans.
Vitamin C is a highly effective antioxidant. It is also required for required for the synthesis of collagen, an important structural component of blood vessels, tendons, ligaments, and bone. Vitamin C is required for the synthesis of carnitine, a small molecule that is essential for the transport of fat to cellular organelles called mitochondria, for conversion to energy. Humans do not have the ability to make their own Vitamin C, therefore, they must obtain it through diet. The richest source of Vitamin C is from fresh fruits and vegetables. Vitamin C is also the most widely taken nutritional supplement.