Vitamins and Nutrional Supplements
Nutritional supplements, vitamins and herbal products, have become an unnecessary part of many peoples’ diets in the 20th century. A common misconception is if a little is good then more is better. If you eat a balanced diet containing 1800-2000 Calories per day you should not need additional vitamins in your diet. Exception to this are people with difficulty absorbing foods and medications (malabsorption syndromes), who are pregnant or who are under exceptional stress.
Vitamins are either water-soluble or fat-soluble. Excessive doses of water-soluble vitamins are simply excreted in the urine, but do no harm. Excessive doses of fat-soluble vitamins can be toxic.
Water-soluble vitamins include vitamin C and the B vitamin complex. They are for the most part, carried in the blood stream; excreted in the urine; needed in frequent, small doses; and unlikely to be toxic, except when taken in unusually large quantities.
Fat-soluble vitamins, include vitamins A, D, E and K. They are, in general, absorbed into the lymph system first and then carried in the blood by protein carriers. Fat-soluble vitamins are stored in fat tissues, needed in periodic doses, and more likely to be toxic when consumed in excess of needs.
Water Soluble Vitamins
B1 (Thiamine): A balanced diet is the key to obtaining adequate amounts of
B2 (Riboflavin): the B vitamins. Meat and meat alternatives provide
B3 (Niacin): thiamine, niacin, vitamin B6, and B12 well. Milk and milk
B6 (pyridoxine): products stand out for riboflavin and vitamin B12. Fruits
Folate: and vegetables excel for folate. Bread and grains deliver
B12 (cyanocobalamin): thiamine, riboflavin, and niacin. A diet that offers a variety
Biotin: of foods from each of the food groups will provide an
Pantothenic Acid (B5): adequate intake of the B vitamins.
Vitamin C is found in citrus fruits, vegetables, cantaloupe, strawberries, tomatoes, potatoes, and lettuce to name a few. Years ago, when sailors would be at sea for months to years at a time, many would develop scurvy because their diet lacked fresh fruits and vegetables. Today, scurvy is almost unheard of. However, there are many people taking large amounts of vitamin C for its antioxidant properties or for prevention of colds. Vitamin C can be toxic when taken in huge amounts. Symptoms of toxicity include nausea, abdominal cramps, diarrhea, headache, fatigue, insomnia, hot flashes, and excessive urination. Vitamin C can also cause interference with some medical tests.
Fat Soluble Vitamins
Vitamin A is important for vision, mucous membranes, growth of teeth and bones, hormone synthesis and regulation, and immunity. Deficiency of vitamin A is rare, due to the body’s ability to store nearly a years supply of vitamin A. Toxicity is more common, because the body does store excess vitamin A versus excreting it. Symptoms of toxicity include increased bone breakdown, joint pain, decreased clotting ability, dry skin, brittle nails, loss of hair, nausea, abdominal pain, irritability, fatigue, and muscle weakness.
Vitamin D is different from all the other nutrients in that the body can synthesize it with the help of sunlight. Because it is a fat-soluble vitamin, the body does have the ability to store any excess. Vitamin D is important for the absorption of calcium and is often supplemented in post-menopausal women taking calcium. Due to its important role in the development of bones, it is important for infants and children to have exposure to sunlight so the body can synthesize vitamin D. However, if taken in large amounts, vitamin D can be harmful. Toxicity can cause increased excretion of calcium, kidney stones, calcification of soft tissues, headache, weakness, and fatigue.
Many extravagant claims have been made for vitamin E. A ll kinds of people take vitamin E supplements for all kinds of reasons. As a result, some signs of toxicity are now known or suspected, but toxicity is not common. Most common toxicity symptoms are GI complaints. High doses of vitamin E do enhance anticoagulation effects of drugs, people given anticoagulant therapy, therefore, should not take large amounts of vitamin E.
The primary role of vitamin K in the body is blood clotting. When any of the factors required for coagulation is lacking, blood cannot clot. Excessive vitamin K may cause the blood to clot too easily. Vitamin K will cause the anticoagulant effects of drugs to be ineffective, therefore, people given anticoagulant therapy should not take large amounts of vitamin K.