The Importance of Vitamins for Optimal Health

1. Vitamins • Early on in nutritional research we recognized that there were some substances in foods that were vital for life. Since the 1900s the study of vitamin’s roles in human physiology has continued at a dramatic pace. “Lecture 9: Vitamins PowerPoint" by Dr. Michael Kobre, Achieving the Dream OER Degree Initiative, Tompkins Cortland Community College is licensed under CC BY 4.0

2. The Vitamins • Vitamins support nutritional health. Keep in mind that vitamin supplements do not offer as many benefits that come from vitamin-rich foods. • Vitamins are essential for normal physiological functioning and homeostasis. Vitamins have many roles in the body. For example: Vitamin C not only prevents the deficiency disease scurvy, but also seems to protect us against certain types of cancer.

3. The Vitamins • A vitamin A deficiency can cause blindness; a lack of the B vitamin niacin can cause dementia; and a lack of vitamin D can retard bone growth. • The consequences of vitamin deficiencies are so debilitating and the effects of restoring the needed vitamins so dramatic, that people often spend billions of dollars every year in belief that vitamins will cure a host of ailments in the human body.

4. The Vitamins • Some research suggests that vitamin E seems to help protect against some forms of CAD. The B vitamin folate is important in the prevention birth defects. • As you will see, the vitamins’ roles in supporting optimal health extend far beyond preventing deficiency diseases. In fact, some of the credit given to low-fat diets in preventing disease actually belongs to the vitamins that diets rich in vegetables, fruits and whole grains bring into the body.

5. The Vitamins • Vitamin differ from carbohydrates, fats, and proteins in the following ways: • Structure: vitamins are individual units, they are not linked together. • Function: Vitamins do not yield useable energy when broken down but they assist the enzymes that release energy from CHO, fats, and Protein. • Food contents: The amounts of vitamins people ingest daily from foods is much smaller in mass, usually vitamins are measured in micrograms or milligrams instead of grams.

6. Bioavailability • The availability of vitamins in foods depends on two factors: the quantity provided by a food source and the amount absorbed and used by the body. Researchers analyze foods to determine their vitamin contents and then they are published the in data tables of food composition.

7. Bioavailability • Determining the bioavailability of a vitamin is a more complex task because it depends on many different factors including • Efficiency of digestion/absorption and time of transit through the GI tract. • Previous nutritional intake and current nutrition status. • What foods consumed at the same time. • Food preparation, raw, cooked, or processed. • Source of the nutrient, if it is synthetic, fortified, or naturally occurring.

8. Precursors • Some of the vitamins are available from foods in inactive forms known as precursors, or provitamins. Once inside the body, the precursor is changed chemically to an active form of the vitamin that becomes functional.

9. Organic Nature Being organic (carbon containing), vitamins can be destroyed an then are unable to perform their functions in the body. Vitamins must be handled with care during storage and in cooking to preserve their function.

10. Organic Nature • One example, oxygen destroys vitamin C, so losses occur when foods are cut or open exposing them to the air.

11. Solubility • As you may recall, carbohydrates and proteins are hydrophilic (water-loving), and lipids are hydrophobic. • The vitamins are similar, the hydrophilic water-soluble one are the B vitamins and vitamin C. The hydrophobic, fat-soluble vitamins are A,D,E and K. they are handled, transported, and stored differently in the body.

12. Solubility • As each vitamin was researched, it was given a name and sometimes a letter and number designation as well. Many of the water-soluble vitamins have multiple names, which can lead to some confusion. • Solubility in the food sources of the different vitamins, affects their absorption, transport, storage, and excretion by our body.

13. Solubility • Water soluble-vitamins are found in the watery compartments of foods. Fat-soluble vitamins usually occur together in the fats and oils of foods. • On being absorbed, the water-soluble vitamins move directly into the blood. As with fats, the fat-soluble vitamins must first enter the lymph, then the blood stream using special transport carriers.

14. Solubility • Once in the blood stream, many of the water-soluble vitamins will continue to circulate around with the blood. Fat-soluble vitamins require protein carriers for transport in the body. • Our kidneys monitor the blood that flows through them and can detect and remove small excesses of water-soluble vitamins flushing excesses out in our urine.

15. Solubility • Large excesses of water-soluble vitamins can overwhelm the body creating negative effects. Fat-soluble vitamins are stored in adipose cells with body fat site instead of being excreted. Fat soluble vitamins are more likely to reach toxic levels when consumed in excess when compared to water soluble vitamins.

16. Solubility • Because the body stores fat-soluble vitamins, they can be eaten in excess amounts on occasion and still meet the body’s needs over time. Water- soluble vitamins are retained for varying periods in the body. A single day’s omission from the diet will not bring on a deficiency, but water soluble vitamin must be consumed more regularly than the fat-soluble vitamins.

17. Toxicity • Knowledge about some of the roles of vitamins has prompted many people to begin taking excess supplements, assuming that more is better. Just as an inadequate intake can cause harm, so can an excessive intakes of vitamins. Some of the water-soluble vitamins have toxic effects when taken in large doses.

18. Toxicity • Of the nutrients discussed in this course, niacin, vitamin B6, folate, choline, and vitamin C have upper intake levels set. Data is still lacking to establish upper intake levels for the remaining B vitamins, but this does not mean that excessively high intakes would be without toxic risk.

19. The B Vitamins • Thiamin: is the vitamin part of the coenzyme thiamin pyrophosphate which assists in energy metabolism. This coenzyme participates in the conversion of pyruvate to acetyl CoA. Along with roles in metabolism, thiamin attaches to a special site on the membranes of nerve cells and in their responding tissues. Muscles, depend heavily on thiamin for normal function.

20. Thiamin B1 • Dietary recommendations are based on thiamin’s role in enzyme activity. Generally, if a person eats enough food to meet their energy needs and obtains energy from nutritious foods, thiamin intake will be adequate.

21. Thiamin Deficiency • People who fail to eat enough food to meet energy needs risk nutrient deficiencies, including thiamin deficiency. Thiamin deficiency has been often reported among malnourished and homeless people. People who derive most of their energy from empty-kcal foods and alcohol will risk a thiamin deficiency.

22. Thiamin Deficiency • An estimated 4 out of 5 alcoholics are thiamin deficient. • Wernicke-Korsakoff syndrome: symptoms include disorientation, loss of short term memory, jerk eye movements, and staggering gait.

23. Thiamin Deficiency • Beriberi: Is a long term thiamin deficiency condition that has two presentations, “wet” or “dry” types. Wasting with edema or just muscle wasting. Also damage to the nervous system, muscles, including cardiac tissue. • This condition was first seen in East Asia when the custom of “polishing” rice became widespread. Rice provided ~80% of the energy intake of the people of that area, and rice bran and germ were their principle source of thiamin. Polishing rice takes away the parts of the rice that contain thiamin.

24. Thiamin Food Sources • Many different foods contribute some thiamin to the diet but few are good sources. Consuming several servings of a variety of different nutrient dense foods can help us to meet our thiamin needs. Pork is high in thiamin. When we consume grain products, we should choose whole gain or enriched products.

25. RDA for Thiamin (B1) • Men should consume: 1.2 mg/day • Women: 1.1 mg/day • Deficiencies can cause: enlarged heart, cardiac failure, weakness, apathy, poor short-term memory, confusion, anorexia and weight loss. • Toxicity symptoms: none are currently reported.

26. Riboflavin • Riboflavin also has roles as a coenzyme in many reactions, most noteworthy, the release of energy from nutrients in all of the body’s cells. The coenzyme forms of riboflavin are flavin mononucleotide and flavin adenine dinucleotide. Both of these molecules play critical roles in cell metabolism.

27. Riboflavin • As with thiamin’s RDA, riboflavin’s RDA is based primarily on its function in enzyme activity. Most of us in the United States generally meet or exceed riboflavin recommendations. • Men should consume: 1.3 mg/day • Women: 1.1 mg/day

28. Riboflavin B2 Deficiency • No single disease is associated with riboflavin deficiency. Deficiencies of the vitamin can cause inflammation of the membranes of the mouth, skin, eyes and GI tract.

29. Riboflavin Food Sources • The greatest sources of riboflavin come from milk and other dairy products. Liver, clams, feta cheese, eggs, and dark green leaf vegetables, such as spinach and broccoli are good sources too.

30. Niacin B3 • Niacin has many names including: Nicotic acid, nicotinamide, niacinamide. The precursor to niacin is the amino acid tryptophan. • Niacin is unique when compared to the other B vitamins in that the body can synthesize it from the amino acid tryptophan. To make 1 mg of niacin requires 60 mg of dietary tryptophan to be available for the conversion.

31. Niacin Recommendations • Recommended intakes are shown in niacin equivalents. For example, a food containing 1mg of niacin and 120mg of tryptophan provides 3mg of niacin or 3 niacin equivalents. • RDA Men: 16mg NE/day • RDA Women: 14mg NE/day

32. Niacin Deficiency • Causes Pellagra: A niacin-deficiency disease produces the four symptoms of diarrhea, dermatitis, and dementia, leading to death if untreated. In the 1900s, pellagra caused widespread deficiencies and some 87,000 deaths in the southern United States, where many people consumed a diet of low-protein that was based on corn.

33. Niacin Deficiency • This low protein corn-based diet supplied not enough niacin or tryptophan. At least 70% of the niacin in corn is bound to fiber and small peptides, making it unavailable for human digestion or absorption. Corn is also contains the amino acid leucine, which interferes with the tryptophan-to-niacin conversion in the body.

34. Niacin Deficiency • Pellagra was first thought to be caused by infectious agents until we found that the problem was deficient niacin. The fact that a disease such as pellagra could be caused by something lacking in the diet and not by a germ was a unique discovery at the time.

35. Niacin Toxicity • Naturally occurring niacin from foods causes no harm, but large doses consumed from supplements can produce a variety of adverse effects, most notably a condition called niacin flush. Niacin flush occurs when niacin in the form of nicotinic acid is taken in doses as low as three to four times the RDA. It dilates the capillaries and causes a tingling sensation that can be painful.

36. Niacin Toxicity • Large doses of nicotinic acid (~3000 mg/day) have been used to lower blood cholesterol. Any therapy should be closely monitored because of the toxic side effect like liver damage had can occur. Some folks with the following conditions may be particularly susceptible to the toxic effects of niacin. People with liver disease, diabetes, ulcers, gout, heart conditions, and migraine headaches.

37. Niacin Food Sources • Eggs, milk, meat, poultry, fish, whole grain and enriched breads and cereals, nuts, and all protein-containing foods are good sources of niacin.

38. Biotin • Biotin plays an important role as a coenzyme that carries activated carbon dioxide. This role is critical in cellular metabolism for energy production in the body.

39. Biotin • Biotin is needed in very small amounts in the body. Because of the small amounts needed, an Adequate intake level has been determined. • AI: Adults- 30 micrograms/day. Biotin deficiencies rarely occur. A protein in egg whites binds biotin and can prevent its absorption if eaten in very large amounts.

40. Biotin Food Sources • Biotin is widespread in foods so eating a variety of foods prevents against deficiencies. Biotin is also synthesized by GI tract bacteria, but how much of it is absorbed and used by the body is still under active research.

41. Pantothenic Acid • Is involved in many different processes in the construction of lipids, neurotransmitters, steroid hormones, and hemoglobin in our body. It also functions as a part of coenzyme A in metabolic activities.

42. Pantothenic Acid Recommendations • An AI for pantothenic acid has been researched. The amount reflects how much we need to replace our daily loses. • AI for Adults: 5 mg/day

43. Pantothenic Acid Deficiency • Deficiency is fairly rare. Symptoms of deficiency include a general failure of most of the body’s organ systems and include fatigue, GI distress, and neurological disorders. A condition called Burning feet syndrome that was reported in prisoners of war in Asia during World War II may have been caused by pantothenic acid deficiencies.

44. Pantothenic Acid Food Sources • Pantothenic acid is found in many foods. Typical dietary intakes seem to good levels of pantothenic acid. Diets containing beef, poultry, whole grains, potatoes, tomatoes, and broccoli are good sources. Losses of pantothenic acid during food production can be substantial because it can be destroyed by packaging and some refining processes.

45. Vitamin B6 • Is found in three different forms. Pyridoxal, pyridoxine, and pyridoxamine. All three forms can be converted to an enzyme that functions in amino acid metabolism. Vitamin B6 can help function in the transfer amino groups when our liver is synthesizing nonessential amino acids.

46. Vitamin B6 Recommendations • Because vitamin B6 coenzymes play many roles in amino acid metabolism, previous RDA were based on levels of protein intakes but since as been changed. • RDA for Adults: 1.3 mg/day • Upper RDA level: 100 mg/day

47. Vitamin B6 Deficiency • Without adequate B6, synthesis of important neurotransmitters diminishes, and abnormal compounds produced during tryptophan metabolism can form and may accumulate in the central nervous system, mainly in the brain. Symptoms of B6 deficiency include depression and confusion. More advanced symptoms include abnormal brain wave patterns and convulsions leading to death.

48. Vitamin B6 Toxicity • The first report of vitamin B6 toxicity appeared in 1983. Up until that time, researchers believed that, like some other water-soluble vitamins, B6 could not reach toxic concentrations in the body. • The report at the time showed neurological damage in people who had been taking more than 2 grams of B6 daily with was twenty times the current upper limit for 60 plus consecutive days.

49. Vitamin B6 Toxicity • It has been reported that some women use B6 supplements in an attempt to treat premenstrual syndrome (PMS). Research has shown that B6 seems to be more detrimental than good in treating PMS.

50. Vitamin B6 Food Sources • Meats, fish, poultry, potatoes, legumes, noncitrus fruits, fortified cereals, liver, and soy products are all good sources of B6. • It should be noted that high levels of heat can damage B6 causing it to be non-functional.