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Vitamins do not contain calories and therefore are not sources of energy. They do help convert our sources of energy into energy by acting as coenzymes. Many biochemical processes and metabolic reactions depend on vitamins to function.
Vitamins are assistants in metabolism; they are not part of our body structure or tissues. They are co-factors that are essential for metabolism to occur.
Most water-soluble vitamins are measured in milligrams (mg) or micrograms (mcg), while fat-soluble vitamins are typically measured in international units (IU). International units are an international standard that measures potency, as opposed to weight or volume.
Vitamins depend on food and specific minerals to be absorbed. They are critical to every function including growth, vitality, digestion, elimination, and resistance to disease. Deficiency results in disorders symptomatic of the particular metabolic pathway that is not functioning properly.
Vitamins were only recently scientifically discovered. Sailors have known for centuries that something in citrus fruits could prevent scurvy, which we now know is a vitamin C deficiency, on long voyages. In the early 1900s, Sir Frederick Galen Hopkins published a paper suggesting that there were some "accessory nutrients" needed in small quantities to maintain good health. Then, in 1911, the first vitamin - thiamine - was isolated from rice polishings. Thiamine was found to be an amine. It was named "vitamine" or "amine essential for life." The term was later converted to our current one, vitamin.
A system was developed during World War II to determine a minimum nutrient intake to prevent deficiency diseases from occurring. This system was called the Recommended Daily Allowance or RDA. These basic nutritional guidelines were required to be placed on nutrition panels on manufactured foods. The system, recently renamed Reference Daily Intake (or RDI) is the current standard.
Though the name changed, the values are essentially the same. There is much controversy among nutritionists, dieticians, doctors, and others about the value of the current system. Because it was developed so long ago and originally intended to prevent malnourishment, many believe it to be inadequate.
Today, many nutrition professionals are calling for revised standards and are suggesting ranges, rather than minimums. Most people would like to know the optimum daily intake supporting vitality and the highest level of well-being rather than meeting a minimum designed just to keep you from getting sick. Though those who are under more stress or are very athletic have higher needs than a sedentary person, the system does provide basic guidelines for everyone to use.
Vitamins are classified into two groups; water-soluble and fat-soluble. Letters, groups, and individual chemical names further categorize vitamins.
Water-soluble Vitamins
Water-soluble vitamins that are stable in raw foods can be lost easily while cooking and processing. Water-soluble vitamins are readily available in vegetables and fruits, but less so in most animal sources. Water-soluble vitamins are generally not stored in the body and are excreted within four hours to one day. This means regular consumption critical. However, this also means the potential for toxicity, due to excessive intake, is very low. The function of most water-soluble vitamins is to act as coenzymes that combine with an inactive protein, which then becomes an active enzyme.
Fat-Soluble Vitamins
The fat-soluble vitamins are found in the lipid component of both vegetable and animal sources. They are vitamins A, D, E, and K. Vitamin A can also be converted from its precursor, beta-carotene, an orange pigment found in many vegetables.
Fat-soluble vitamins can be stored in body tissues enabling normal function for longer time periods between obtaining them from the diet. This storage capacity can also allow toxic levels to potentially build up. This is especially true for vitamins A, D, and K. Vitamin E toxicity is less likely since it is used throughout the body as an antioxidant to help protect from the harmful side effects of oxidation and outside pollutants.
Vitamin supplements have become very popular and important in today's world. While a person can meet all of their nutritional needs through a good, well-planned diet; it is not always possible to achieve the perfect balance of food consumption. In addition, many of the foods that are available today are highly processed and manipulated. We are all faced with many situations where good, whole food, nutrition-packed food choices are just not an option. Nutritional supplements can play a significant role in helping us maintain our health.
Nutritional supplements can also be of great value therapeutically when a person is ill. Supplements can help boost immune function, correct nutritional deficiencies, and improve energy levels and tissue repair abilities within the body.
There are great differences in quality and production methods associated with nutritional supplement manufacturing. Naturally-occurring vitamins are far superior to synthetically produced versions. Synthetic vitamins do not interact with the metabolism nearly as efficiently and can even become toxic. Furthermore, many unscrupulous vitamin companies add unnecessary and potentially harmful colorings, dyes, preservatives, and chemicals to aid in manufacturing and marketing. It is wise to do research, ask reputable and knowledgeable professionals, and be cautious before choosing a nutritional supplement.
