The Water-Soluble Vitamins: B Vitamins and Vitamin C Chapter 10

The Vitamins – An Overview Vital to health, organic, and available in foods Vitamins differ from macronutrients Structure Function Food contents Both deficiency and excess of vitamins can affect health

The Vitamins – An Overview Bioavailability Quantity provided by food Amount absorbed and used by body Factors influencing bioavailability

The Vitamins – An Overview Precursors AKA Provitamins Organic nature Can be destroyed during storage and in cooking

The Vitamins – An Overview Solubility Affects absorption, transport, and excretion Water-soluble (B vit & vit C) VS Fat-soluble Consumption frequency of vitamins

The Vitamins – An Overview Toxicity More is not necessarily better Excessive intakes

The B Vitamins – As Individuals Very active in the body, but do not provide the body with fuel for energy. Several B vits form part of the coenzymes Others participate in metabolism and cell multiplication. Recommendations for B vits come from RDA, AI, and Tolerable Upper Intake Levels. deficiencies, toxicities, and food sources are unique for each

The B Vitamins – As Individuals

The B Vitamins – Thiamin Part of coenzyme thiamin pyrophosphate (TPP) Energy metabolism Nerve activity and muscle activity Recommendations: RDA Men: 1.2 mg/day. RDA Women: 1.1 mg/day.

The B Vitamins – Thiamin Deficiency Malnourished and alcoholics Deficiency symptoms: Enlarged heart and possible cardiac failure. Muscular weakness. Apathy, poor short-term memory, confusion, and irritability. Anorexia and weight loss. Wernicke-Korsakoff syndrome is a severe deficiency that develops in those who abuse alcohol. Deficiency results in the disease beriberi (dry & wet) Toxicity None reported

The B Vitamins – Thiamin Food sources: Whole-grain, fortified or enriched grain products Moderate amounts in all foods Pork Other Information: easily destroyed by heat) Leaches into water Steaming and microwaving

The B Vitamins – Thiamin

The B Vitamins – Riboflavin Riboflavin (Vitamin B2): Involved in energy metabolism. Coenzyme forms: Flavin mononucleotide (FMN) & flavin adenine dinucleotide (FAD) Recommendations RDA Men: 1.3 mg/day; Women: 1.1 mg/day Deficiency Inflammation of membranes Deficiency symptoms Deficiency disease is ariboflavinosis. Toxicity No reported toxicities

The B Vitamins – Riboflavin Food sources Milk and milk products, including yogurt and cheese Whole-grain, fortified, and enriched grain products Liver Destruction of riboflavin Destroyed Not destroyed by cooking

The B Vitamins – Riboflavin

The B Vitamins – Niacin(Vitamin B3) Two chemical structures Nicotinic acid Nicotinamide Two coenzyme forms – metabolic reactions Nicotinamide adenine dinucleotide (NAD) NADP (the phosphate form)

The B Vitamins – Niacin RDA is stated in niacin equivalents Recommendations Body manufacturers from tryptophan RDA is stated in niacin equivalents RDA Men: 16 NE/day. RDA Women: 14 NE/day. Upper level of 35 mg/day for adults.

The B Vitamins – Niacin Deficiency Toxicity Pellagra Symptoms Deficiency symptoms: Toxicity Supplements or drugs Niacin flush Toxicity symptoms Potential health benefits of large doses of nicotinic acid:

The B Vitamins – Niacin Food sources Other Information Milk, eggs, meat, poultry, and fish Whole-grain and enriched breads and cereals Nuts and all protein-containing foods Other Information Also called nicotinic acid, nicotinamide, and niacinamide. The amino acid tryptophan is the precursor. The vitamin can be lost from foods when it leaches into water.

The B Vitamins – Niacin

The B Vitamins – Biotin As part of a coenzyme used in energy metabolism Coenzyme that carries activated carbon dioxide Critical in TCA cycle Participates in gluconeogenesis and fatty acid synthesis Participates in breakdown of fatty acids and amino acids

The B Vitamins – Biotin Recommendations – AI Adults: 30 g/day. Deficiency and Toxicity Deficiencies are rare. Deficiency symptoms: No reported toxicities.

The B Vitamins – Biotin Biotin can be bound with an egg-white protein called avidin. Food Sources: Widespread in foods. Organ meats, egg yolks, and fish. Soybeans. Whole grains. Biotin can also be synthesized by intestinal bacteria.

The B Vitamins – Pantothenic Acid Part of chemical structure of coenzyme A, used in E metabolism Recommendations AI: Adults 5mg/day Deficiency Rare Symptoms:

The B Vitamins – Pantothenic Acid Toxicity None reported Food sources (Widespread in foods): Chicken, beef, liver, and egg yolks. Potatoes, tomatoes, and broccoli. Whole grains and oats. Can be destroyed by freezing, canning, and refining.

The B Vitamins – B6 Three forms: Pyridoxal, pyridoxine, and pyridoxamine Recent research claiming influence on cognitive performance, immune funx, steroid hormone activity. Stored exclusively in muscle tissue

The B Vitamins – B6 Recommendations Deficiency Adults (19-50yrs): 1.3mg/day Deficiency Symptoms: Alcohol destroys the vitamin. Isoniazid (INH) drug used for tuberculosis acts as an antagonist.

The B Vitamins – B6 Toxicity Upper level for adults: 100 mg/day. Food sources Meats, fish, poultry, and liver Legumes and soy products Non-citrus fruits Fortified cereals, potatoes and other starchy vegetables.

The B Vitamins – B6

The B Vitamins – Folate Known as folacin or folic acid Primary coenzyme form – THF (tetrahydrofolate) Transfers single-carbon compounds during metabolism

The B Vitamins – Folate Recommendations RDA Adults: 400 g/day. Dietary Folate Equivalents (DFE) Higher recommendations for pregnant women. Folate and Neural Tube Defects Pregnant women should take folate supplements.

The B Vitamins – Folate Folate and Heart Disease High levels of homocysteine and low levels of folate increase risk of heart disease. Folate breaks down homocysteine. Folate may help to prevent cancer, but may also promote cancer growth once cancer has developed.

The B Vitamins – Folate Deficiency Elevated homocysteine levels. Most vulnerable of all the vitamins to interactions with medications. Toxicity Masks vitamin B12 deficiency symptoms.

The B Vitamins – Folate Toxicity: Food Sources Upper level for adults: 1000 g/day. Food Sources Fortified grains Leafy green vegetables Legumes and seeds Liver Easily destroyed by heat and oxygen.

The B Vitamins – Folate

The B Vitamins – Vitamin B12 Cobalamin – Methylcobalamine and deoxyadenosylcobalamin are the coenzyme forms. Recommendations RDA Adults: 2.4 g/day.

The B Vitamins – Vitamin B12 Deficiency symptoms Anemia Fatigue and degeneration of peripheral nerves progressing to paralysis. Sore tongue, loss of appetite, and constipation. Deficiency disease is called pernicious anemia.

The B Vitamins – Vitamin B12 No known toxicities Food Sources. Meat, fish, poultry, and shellfish. Milk, cheese, and eggs. Fortified cereals. Other Information Binds with intrinsic factor Easily destroyed by microwave cooking.

The B Vitamins – In Concert Each B vitamin coenzyme is involved in energy metabolism Directly Indirectly Deficiencies Single B-vitamin deficiencies seldom show up in isolation

The B Vitamins – In Concert The B Vitamins are interdependent Presence of one may affect the absorption, metabolism, and excretion of another. A deficiency of one may affect the functioning or deficiency of another. A variety of foods from each food group will provide an adequate supply of all the B vitamins.

The B Vitamins – In Concert B Vitamin Roles Coenzymes involved directly or indirectly with energy metabolism. Facilitate energy-releasing reactions. Build new cells to deliver oxygen and nutrients for energy reactions. B Vitamin Deficiencies Deficiencies rarely occur singly except for beriberi and pellagra. Can be primary or secondary causes. Glossitis and cheilosis are two symptoms common to B vitamin deficiencies. Symptoms that individuals experience are not necessarily related to a vitamin deficiency.

The B Vitamins – In Concert B vitamin toxicities can occur with supplements. B Vitamin Food Sources Grains group provides thiamin, riboflavin, niacin and folate. Fruits and vegetables provide folate. Meat group provides thiamin, niacin, vitamin B6, and vitamin B12. Milk group provides riboflavin and vitamin B12.

The B Vitamins – In Concert

Vitamin C – Roles Antiscorbutic factor is the original name Roles Serves as a cofactor to facilitate the action of an enzyme Antioxidant As a Cofactor in Collagen Formation

Vitamin C Needs increase during body stress, As a Cofactor in Other Reactions Hydroxylation of carnitine Converts tryptophan to neurotransmitters Makes hormones Needs increase during body stress, i.e. infections, burns, extremely high or low temperatures, heavy metal intakes, certain medications, and smoking

Vitamin C Vitamin C Recommendations Deficiency In the Prevention and Treatment of the Common Cold Role in disease prevention is still being researched Vitamin C Recommendations RDA Men: 90 mg/day; Women: 75 mg/day Smokers: +35 mg/day Deficiency Disease is called scurvy Deficiency symptoms

Vitamin C – Deficiency

Vitamin C Toxicity Food Sources Other information Upper level for adults: 2000 mg/day Food Sources Citrus fruits, cantaloupe, strawberries, papayas, and mangoes Cabbage-type vegetables, dark green vegetables like red peppers and broccoli, lettuce, tomatoes, and potatoes Other information Also called ascorbic acid Easily destroyed by heat and oxygen

Vitamin C – Food Sources