1. Chapter 8 The Water-Soluble Vitamins

2. Copyright 2010, John Wiley & Sons, Inc. Vitamin Talk Vitamins are organic compounds essential in the diet to promote growth and health maintenance. Water-soluble vitamins include the B vitamins and vitamin C. Fat-soluble vitamins include A, D, E and K. B vitamins were originally thought to be one chemical substance but are actually many different substances. That is the reason for B 1, B 2, B 12, etc.

3. Copyright 2010, John Wiley & Sons, Inc. The Vitamins

4. Copyright 2010, John Wiley & Sons, Inc. Finding Vitamins in Foods

5. Copyright 2010, John Wiley & Sons, Inc. Fortified and Enriched Foods Fortification: process of adding nutrients to foods. The added nutrients are generally not found in the food, such as fortifying orange juice with calcium. Enrichment: adding nutrients back to foods that have lost nutrients due to processing. An example is the addition of B vitamins to white rice.

6. Copyright 2010, John Wiley & Sons, Inc. Dietary Supplements Dietary supplements can be another source of vitamins in the modern diet. Dietary supplements contain some combination of vitamins, minerals, herbs, botanicals, amino acids, enzymes or extracts. Dietary supplements cannot replace the benefits of a diet containing a wide variety of foods. Dietary supplement production is not supervised by the FDA.

7. Copyright 2010, John Wiley & Sons, Inc. Absorption of Vitamins

8. Copyright 2010, John Wiley & Sons, Inc. Bioavailability of Vitamins Vitamins must be absorbed by the body in order to perform their functions. Approximately 40-90% of vitamins are absorbed in the small intestine. Fat-soluble vitamins require fat in the diet to be absorbed. Water-soluble vitamins may require transport molecules or specific molecules in the GI tract. Some vitamins are absorbed in inactive provitamin or vitamin precursor forms that must be converted into active forms by the body.

9. Copyright 2010, John Wiley & Sons, Inc. Thiamin Thiamin was the first B vitamin to be identified and is also called B 1. Thiamin is widely available in foods, especially in enriched grains, whole grains, legumes, nuts and seeds. Thiamin assists in energy production, carbohydrate metabolism, the production of ribose and the health of the nervous system.

10. Copyright 2010, John Wiley & Sons, Inc. Thiamin

11. Copyright 2010, John Wiley & Sons, Inc. Riboflavin Dairy products are a good source of riboflavin. Plant sources of riboflavin include mushrooms, broccoli, asparagus, whole grains and green, leafy vegetables. Animal sources include red meat, poultry and fish. Riboflavin is easily destroyed by heat and exposure to light. Riboflavin is an important component in the citric acid cycle and for assisting the body with the absorption of other vitamins.

12. Copyright 2010, John Wiley & Sons, Inc. Riboflavin

13. Copyright 2010, John Wiley & Sons, Inc. Niacin Niacin is added to enriched flours in North America. A niacin deficiency disease is pellagra. Niacin can be synthesized in the body from the essential amino acid tryptophan if the diet is adequate in tryptophan. Niacin plays an important role in the production of energy and in general metabolism. Two forms of niacin are nicotinic acid and nicotinamide.

14. Copyright 2010, John Wiley & Sons, Inc. Niacin

15. Copyright 2010, John Wiley & Sons, Inc. Niacin Advanced pellagra’s symptoms include the 3 D’s: dermatitis, diarrhea and dementia. Niacin toxicity from overuse of niacin supplements can result in elevated blood pressure, cardiac arrhythmia, nausea, vomiting, elevated blood sugar levels and impaired liver function.

16. Copyright 2010, John Wiley & Sons, Inc. Pantothenic Acid

17. Copyright 2010, John Wiley & Sons, Inc. Vitamin B 6

18. Copyright 2010, John Wiley & Sons, Inc. Vitamin B 6 Vitamin B 6 is also called pyridoxine and comprises a group of compounds including pyridoxal, pyridoxine, and pyridoxamine. All three forms can be converted into pyridoxal phosphate, which is required for many enzyme reactions in the body. Vitamin B 6 deficiency may result in anemia due to impaired hemoglobin synthesis and neurotransmitter issues.

19. Copyright 2010, John Wiley & Sons, Inc. Folate or Folic Acid

20. Copyright 2010, John Wiley & Sons, Inc. Folate or Folic Acid Folate coenzymes are needed for DNA synthesis and the metabolism of some amino acids. Low folate intake in early pregnancy is associated with an increased risk of neural tube defects. Low folate intake has been associated with an increased risk of heart disease related to the metabolism of the amino acid homocysteine.

21. Copyright 2010, John Wiley & Sons, Inc. Folate Deficiency and Neural Tube Defects

22. Copyright 2010, John Wiley & Sons, Inc. Macrocytic Anemia and Folate Deficiency

23. Copyright 2010, John Wiley & Sons, Inc. Calculating Dietary Folate Amounts

24. Copyright 2010, John Wiley & Sons, Inc. Vitamin B 12

25. Copyright 2010, John Wiley & Sons, Inc. Vitamin B 12 Pernicious anemia is a form of anemia that does not respond to iron supplementation. Vitamin B 12 is necessary for the proper absorption of iron in the body. Excessive intake of folic acid can mask B 12 deficiencies. Vitamin B 12 is most readily absorbed from animal products. Vegan diets need to be supplemented with readily- absorbable forms of B 12. Atrophic gastritis may lead to B 12 deficiencies.

26. Copyright 2010, John Wiley & Sons, Inc. Absorption of Vitamin B 12

27. Copyright 2010, John Wiley & Sons, Inc. Vitamin C

28. Copyright 2010, John Wiley & Sons, Inc. Vitamin C Vitamin C is also known as ascorbic acid or ascorbate. Vitamin C in foods can be destroyed by oxygen, light and heat, as well as contact with copper or iron cookware. Vitamin C functions as an antioxidant in the body, helps maintain the immune system, is important in the production of collagen and aids in iron absorption.

29. Copyright 2010, John Wiley & Sons, Inc. How Antioxidants Work

30. Copyright 2010, John Wiley & Sons, Inc. Summary of Water-Soluble Vitamins and Choline

31. Copyright 2010, John Wiley & Sons, Inc.

32. Benefits and Risks of Water-Soluble Vitamin Supplements

33. Copyright 2010, John Wiley & Sons, Inc. Chapter 8 Copyright 2010 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages caused by the use of these programs or from the use of the information herein..