Water Soluble Vitamins - Part 1 PDF

FOOD & HEALTH F24 / FDE428 Water Soluble Vitamins: Part-1 Dr. Ipek Bayram Vitamin Overview What are vitamins? What are the two types of vitamins? Where do I get my vitamins? How much do I need? Why are the vitamins important? Vitamins Researchers first recognized in the early 1900s that...

FOOD & HEALTH F24 / FDE428 Water Soluble Vitamins: Part-1 Dr. Ipek Bayram Vitamin Overview What are vitamins? What are the two types of vitamins? Where do I get my vitamins? How much do I need? Why are the vitamins important? Vitamins Researchers first recognized in the early 1900s that foods contain substances that are “vital to life”. What are Vitamins? ❑ They are essential organic components of the biochemical or physiological systems of animal life. ❑ As animals evolved, they lost the ability to synthesize these substances for themselves in adequate amounts. ❑ They tend to occur in only tiny amounts in biological materials. ❑ Their absence from the tissues (whether by absence from the diet or by failure of absorption from the diet) causes a specific deficiency syndrome. Roles of Vitamins Promote growth and reproduction Support nutritional health Differs from energy-yielding nutrients ○ Structure Individual units; not linked together ○ Function No energy yielding ○ Food contents micro/milligrams rather than grams micronutrients Although small in size, the vitamins accomplish giant tasks. Obtaining enough, but not too much, of each vitamin is critical because both deficiencies and toxicities can be harmful.  Classification is based on solubility: Eight water-soluble: B vitamin complex and vitamin C Four fat-soluble: vitamins A, D, E, and K WATER SOLUBLE FAT SOLUBLE B group vitamins Vitamin C Vitamin A Vitamin D B1 Vitamin E B2 Vitamin K B3 B5 B6 B7 B9 B12 Finding Vitamins in Foods Vitamin Absorption and Storage All vitamin absorption takes place in the small intestine. Fat soluble vitamins Absorbed into lymph Storage Vitamin A is mainly stored in the liver. Vitamins K and E are partially stored in the liver. Vitamin D is mainly stored in the fat and muscle tissue. Can build up in body to point of toxicity thus foods are generally fortified in amounts less than DV (e.g., 10%) Vitamin Absorption and Storage Water soluble vitamins Absorbed with water and enter directly into the bloodstream Most are not stored in the body. Excess intake excreted through the urine thus foods could be fortified in amounts higher than DV (e.g. 120%) Important to consume adequate amounts daily Vitamins: Comparison Vitamin Absorption and Storage About 40-90% of the vitamin in food are absorbed. Absorption depends on whether it is fat or water-soluble vitamin. Fat soluble vitamins need fats in the diet. Water soluble vitamins need carriers/transport systems. Need to be transported to cells – also depends on whether it is a fat or water-soluble vitamin Fat soluble vitamins are transported in lipoproteins or specific transport proteins. Water soluble vitamins are bound to blood proteins. Vitamins: Bioavailability Amount of nutrient absorbed and used by the body. The amount of vitamins available from foods depends not only on the quantity provided by a food but also on the amount absorbed and used by the body—referred to as the vitamins’ bioavailability. Fat soluble vitamins are generally less bioavailable than water soluble vitamins. Vitamins from animal foods are generally more bioavailable than those in plant foods. The quantity of vitamins in a food can be determined relatively easily. What about the BIOAVAILABILITY of a vitamin in food? Vitamins: Bioavailability Determining the bioavailability of a vitamin is a more complex task because it depends on many factors, including: ○ Efficiency of digestion and time of transit through the GI tract Enzymes, bacteria ○ Previous nutrient intake and nutrition status Storage, elimination ○ Method of food preparation raw, cooked, or processed ○ Other foods consumed at the same time Fats Vitamins: Stability Fat-soluble vitamins tend to be more stable than water-soluble vitamins. Water-soluble vitamins can be destroyed by: ○ Leaching into water (#1) ○ Oxidation ○ Irradiation (UV light) ○ Heat ○ Changes in pH Vitamins: Stability Fresh foods naturally contain vitamins, but because these vitamins are organic, they can be readily destroyed during processing. Therefore, processed foods should be used sparingly, and fresh foods should be handled with care during storage and in cooking. ○ Prolonged heating may destroy much of the thiamin in food. ○ Ultraviolet rays of the sun or fluorescent light may destroy riboflavin. Thus, foods stored in transparent glass containers are most likely to lose riboflavin. General causes of variation/losses of vitamins in food 1- inherent variation in vitamin content. fruits and vegetables: varies with stage of maturity, fertilizer, and climate Animal products: varies due to biological mechanisms and the diet of the animal General causes of variation/losses of vitamins in food 2- postharvest changes in vitamin content of foods. enzymatic activities (oxidative and hydrolytic) physical damage, temperature abuse, length of time between harvest and processing changes in the chemical forms and therefore, the bioavailability (little influence on the net concentration). 3- preliminary treatment. Trimming and peeling of fruit and vegetables ○ loss of vitamins concentrated in the discarded stem, skin, or peel ○ washing or leaching loss of water-soluble vitamins Milling of cereal grains ○ significant loss of vitamins concentrated in the bran General causes of variation/losses of vitamins in food 4- effects of blanching and thermal processing. Blanching ○ A mild heat treatment, essential in the processing of fruits and vegetables to inactivate deleterious enzymes and reduce microbial loads ○ Accomplished in hot water, flowing steam, hot air ○ Loss of vitamin due to oxidation and leaching, heat is secondary factor. General causes of variation/losses of vitamins in food After blanching, the vegetables can be put in the freezer for quite a long time. Are frozen foods less healthy? General causes of variation/losses of vitamins in food 5- Influence of processing chemicals and food components. Chemicals that influence the pH will directly affect the stability of the pH sensitive vitamins, such as ascorbic acid, thiamin, pantothenic acid, and certain folates. Oxidizing agents directly degrades Vit A, Vit C, Vit E, and indirectly influence other vitamins. Reducing agents stabilize oxidizable vitamins.  Vitamins: Precursors Some of the vitamins are available from foods in inactive forms known as precursors, or provitamins. Once inside the body, the precursor is converted to an active form of the vitamin. For example, beta-carotene, a red-orange pigment found in fruits and vegetables, is a precursor to vitamin A. In measuring a person’s vitamin intake, it is important to count both the amount of the active vitamin and the potential amount available from its precursors. Are you getting the right amount of vitamins from your diet?? Understanding Dose 1 2 3 Response (getting BETTER) Concentration Concentration Concentration (increasing) (increasing) (increasing) Dose response curves Vitamins Dietary Reference Intakes (DRIs) EAR – 50% risk UL – 0% risk RDA – 2-3% risk Inadequate Appropriate Excess  New RDA or AI UL Ages 19-50 Years Ages 19-70 Years Women Men Men & Women Vit A (μg/d) 700 900 3,000 Vit C (mg/d) 75 90 2,000 Vit D (μg/d) 5 5 50 Vit E (mg/d) 15 15 1,000 Vit K (μg/d) 90 120 ND Thiamin (mg/d) 1.1 1.2 ND Riboflavin (mg/d) 1.1 1.3 ND Niacin (mg/d) 14 16 35 B6 (mg/d) 1.3 1.3 100 ND: Normal Diet Addition of vitamins into foods Restoration: Restoring nutrients lost during processing to their original levels in the food. (e.g., vit C to juices) Fortification: Adding nutrients to a food that were either not originally present or present in insignificant amounts (e.g., vit D to juices) Enrichment: Increasing the levels of specific nutrients beyond what was originally found in the food (e.g., folic acid and iron to breakfast cereals) Water Soluble Vitamins (B & C) The B Vitamins The body would lack energy without B vitamins. ○ Help body use macronutrients for fuel Coenzymes ○ Assist enzymes with energy release Ezyme cannot function without coenzyme B Vitamins 1. Thiamin (B1) 2. Riboflavin (B2) 3. Niacin (B3) 4. Pantothenic Acid (B5) 5. Pyrodoxine (B6) 6. Biotin (B7) 7. Folic Acid (B9) 8. Cobalamin (Vitamin B12) Coenzyme Action B Vitamins Coenzyme Roles Vitamin Thiamin Riboflavin Niacin B6 Folate Pantothenic Biotin B12 Acid Coenzyme TPP FAD FMN NAD NADP PLP THF CoA Biotin B12 Protein Metabolism Carbohydrate Met Fat Metabolism NAD PLP PLP TPP FAD FMN NADP FAD FMN NAD THF B12 B12 NAD CoA B12 Biotin CoA B12 ENERGY TPP: Thiamine Pyro Phosphate PLP: Pyridoxal Phosphate THF: Tetrahydrafuran From: Nutrition, An Applied Approach, Thompson and Manroe, 2005 Thiamin (Vitamin B1) Part of coenzyme thiamin pyrophosphate (TPP) Assists in energy metabolism ○ Conversion of pyruvate to acetyl CoA TCA cycle Important for nerve activity and muscle activity Thiamin (Vitamin B1) Thiamin is one of the most unstable vitamins. Thiamin is usually unstable at neutral or alkaline pH. Sulfite added to fruits and vegetables to prevent browning will cause total destruction of the thiamin. Heat treatments such as canning, especially when the pH is above 6.0, cause losses of up to 20% of the thiamin. Up to 30% may be also lost during bread baking. Due to its unstable nature, thiamin cannot be directly applied as a food additive. Thiamin is commercially available as hydrochloride and mononitrate salts for food fortification, which are more stable. Thiamin Deficiency Prolonged thiamin deficiency can result in the disease beriberi, which was first observed in Indonesia when the custom of polishing rice became widespread. Rice provided 80% of the energy intake of the people of that area, and the germ and bran of the rice grain was their principal source of thiamin. When the germ and bran were removed in the preparation of white rice, beriberi became widespread.  Thiamin Deficiency Beriberi is often described as “dry” or “wet.” ○ Dry beriberi reflects damage to the nervous system and is characterized by muscle weakness in the arms and legs. ○ Wet beriberi reflects damage to the cardiovascular system and is characterized by dilated blood vessels, which cause the heart to work harder and the kidneys to retain salt and water, resulting in edema. Typically, both types of beriberi appear together, with one set of symptoms predominating.  Thiamin Deficiency Wernicke-Korsakoff Syndrome ○ A severe neurological disorder caused by chronic thiamin deficiency, often linked to alcohol abuse. Symptoms include confusion, memory loss, and difficulty coordinating movements. TOXICITY: Thiamin is water-soluble, and excess is usually excreted in urine. Toxicity is rare and typically only occurs with intravenous administration; No UL established. Thiamin RDA 1.2 mg men/1.1 mg women Acts primarily as a coenzyme in reactions that release energy from carbohydrate Deficiency disease: Beriberi, Wernicke-Korsakoff Syndrome Thiamin in Foods Rich sources: Pork Whole grains/fortified cereals Soy milk Thiamin Review Riboflavin (Vitamin B2) Serves as coenzyme in energy metabolism ○ Flavin mononucleotide (FMN) ○ Flavin adenine dinucleotide (FAD) Both can accept and then donate two hydrogens ○ During energy metabolism, FAD picks up two hydrogens (with their electrons) from the TCA cycle and delivers them to the electron transport chain Riboflavin Coenzyme: Accepting and Donating Hydrogens Riboflavin (Vitamin B2) More stable than thiamin Sensitive to light ○ 50% of the riboflavin of milk contained in the usual glass bottle may be destroyed by two hours‘ exposure to bright sunlight. ○ When milk is to be sold in supermarkets, whose chilled cabinets are often brightly lit with fluorescent lamps, it is obviously essential that opaque containers rather than the traditional glass bottles are used. Riboflavin can be oxidized into lumiflavin, a stronger oxidizing agent. ○ Lumiflavin can destruct ascorbic acid (vitamin C). Even a small drop of lumiflavin in milk can lead to a near total elimination of the ascorbic acid content. Riboflavin (Vitamin B2) ❑ The greatest contributions of riboflavin come from milk and milk products. ❑ When riboflavin sources ❑ Whole-grain or enriched are ranked by nutrient grains are also valuable density (per kcalorie), sources because of the many dark green, leafy quantities people typically vegetables (such as consume. broccoli, turnip greens, asparagus, and spinach) appear high on the list.  Riboflavin (Vitamin B2) Vegans and others who don’t use milk must rely on ample servings of dark greens and enriched grains for riboflavin. Nutritional yeast is another good source. Ultraviolet light and irradiation destroy riboflavin. For these reasons, milk is sold in cardboard or opaque plastic containers, instead of clear glass bottles. In contrast, riboflavin is stable to heat, so cooking does not destroy it. Riboflavin Deficiency Prolonged riboflavin deficiency can result in the disease ariboflavinosis: ○ Cracks and sores around the mouth ○ Swollen, magenta-colored tongue ○ Skin rashes and inflammation. TOXICITY: Riboflavin is water-soluble, and excess is usually excreted in urine. Toxicity is rare and typically only occurs with intravenous administration, No UL. Riboflavin (Vitamin B2) RDA 1.3 mg men/1.1 mg women Acts primarily as a coenzyme in reactions that release energy from carbohydrate and fats Deficiency disease: ariboflavinosis Riboflavin in Foods Rich sources: Milk Whole grains/fortified cereals Liver Egg Dark leafy vegetables Riboflavin Review Niacin (Vitamin B3) Two chemical structures ○ Nicotinic acid ○ Nicotinamide The body can easily convert nicotinic acid to nicotinamide, which is the major form of niacin in the blood. Two coenzyme forms—participate in metabolic reactions B Vitamins Coenzyme Roles Vitamin Thiamin Riboflavin Niacin B6 Folate Pantothenic Biotin B12 Acid Coenzyme TPP FAD FMN NAD NADP PLP THF CoA Biotin B12 Protein Metabolism Carbohydrate Met Fat Metabolism NAD PLP PLP TPP FAD FMN NADP FAD FMN NAD THF B12 B12 NAD CoA B12 Biotin CoA B12 ENERGY TPP: Thiamine Pyro Phosphate PLP: Pyridoxal Phosphate THF: Tetrahydrafuran From: Nutrition, An Applied Approach, Thompson and Manroe, 2005 Niacin (Vitamin B3) They are central in energy-transfer reactions, including the metabolism of all macronutrients (carbohydrates, fats, and proteins). NAD is similar to the riboflavin coenzymes in that it carries hydrogens (and their electrons) during metabolic reactions, including the pathway from the TCA cycle to the electron transport chain. NAD also protects against neurological degeneration.  Niacin (Vitamin B3) Niacin is less vulnerable to losses during food preparation and storage than other water-soluble vitamins. Being fairly heat resistant, niacin can withstand reasonable cooking times, but like other water-soluble vitamins, it will leach into cooking water. Niacin (Vitamin B3) Niacin is unique among the B vitamins in that the body can make it from the amino acid tryptophan. This use of tryptophan occurs only after protein synthesis needs have been met. Approximately 60 milligrams of dietary tryptophan is needed to make 1 milligram of niacin. For this reason, recommended intakes are stated in niacin equivalents (NE). A food containing 1 milligram of niacin and 60 milligrams of tryptophan provides the equivalent of 2 milligrams of niacin, or 2 niacin equivalents. Niacin Deficiency: The Dermatitis of Pellagra The niacin-deficiency disease, pellagra, produces the symptoms of diarrhea, dermatitis, dementia, and eventually death (often called “the four Ds”). ○ In the early 1900s, pellagra caused widespread misery and some 87,000 deaths in the US, where many people depended on a low-protein diet centered on corn. Niacin Deficiency This diet supplied neither enough niacin nor enough tryptophan. At least 70% of the niacin in corn is bound to complex carbohydrates and small peptides, making it unavailable for absorption. Furthermore, corn is high in the amino acid leucine, which interferes with the tryptophan-to-niacin conversion, thus further contributing to the development of pellagra. Niacin Deficiency Pellagra was originally believed to be caused by an infection. Medical researchers spent many years and much effort searching for infectious microbes until they realized that the problem was not what was present in the food but what was absent from it. That a disease such as pellagra could be caused by diet inadequacies—and not by pathogens—was a groundbreaking discovery (1937). It contradicted commonly held medical opinions that diseases were caused only by infectious agents. Niacin Toxicity Naturally occurring niacin from foods has a physiological effect that causes no(!) harm. Large doses of nicotinic acid from supplements or drugs, however, produce a variety of pharmacological effects, most notably “niacin flush.” Niacin flush occurs when nicotinic acid is taken in doses only three to four times the RDA. It dilates the capillaries and causes a tingling sensation that can be painful. The nicotinamide form does not produce this effect. Niacin Toxicity Large doses of nicotinic acid can effectively raise HDL cholesterol but may not benefit patients with heart disease whose blood lipids are already being controlled with drugs. The use of niacin as a drug must be closely monitored because of possible side effects (such as liver damage). Niacin RDA 16 mg men / 14 mg women Part of coenzyme for energy Can be made from the amino acid tryptophan in the body Deficiency disease: Pellagra Niacin in Foods Rich sources: Chicken Tuna Liver Niacin Review Pantothenic Acid (Vitamin B5) Part of chemical structure of coenzyme A ○ the same CoA that forms acetyl CoA, a key compound in several metabolic pathways It is involved in more than 100 different steps in the synthesis of lipids, neurotransmitters, steroid hormones, and hemoglobin. It promotes wound healing and supports healthy skin, often included in skincare products. Recommendations ○ Widespread in foods ○ Because there is insufficient research on pantothenic acid requirements, an Adequate Intake (AI) has been determined, instead of an RDA. ○ Readily destroyed by freezing, canning, and refining processes.  Pantothenic Acid (Vitamin B5) Deficiency is rare ○ symptoms involve a general failure of all the body’s systems and include: fatigue, GI distress, and neurological disturbances. The “burning feet” syndrome that affected prisoners of war in Asia during World War II is thought to have been caused by pantothenic acid deficiency. No toxic effects have been reported. No UL has been established. Pantothenic Acid Review Pyridoxine (Vitamin B6) Three forms: ○ Pyridoxal ○ Pyridoxine, and ○ Pyridoxamine All can convert to coenzyme PLP which is active in more than 100 reactions including; ○ Carbohydrate, amino acid, and fatty acid metabolism ○ Transfer amino groups → nonessential amino acids ○ Conversion of tryptophan to niacin or serotonin ○ Synthesis of hemoglobin, nucleic acids, and lecithin B Vitamins Coenzyme Roles Vitamin Thiamin Riboflavin Niacin B6 Folate Pantothenic Biotin B12 Acid Coenzyme TPP FAD FMN NAD NADP PLP THF CoA Biotin B12 Protein Metabolism Carbohydrate Met Fat Metabolism NAD PLP PLP TPP FAD FMN NADP FAD FMN NAD THF B12 B12 NAD CoA B12 Biotin CoA B12 ENERGY TPP: Thiamine Pyro Phosphate PLP: Pyridoxal Phosphate THF: Tetrahydrafuran From: Nutrition, An Applied Approach, Thompson and Manroe, 2005 Pyridoxine (Vitamin B6) Unlike other water-soluble vitamins, vitamin B6 is stored extensively in muscle tissue. However, research does not support claims that large doses of vitamin B6 enhance muscle strength or physical endurance. Pyridoxine Deficiency Synthesis of key neurotransmitters diminishes. Abnormal compounds produced during tryptophan metabolism accumulate in the brain. ○ Early symptoms include depression and confusion; ○ Advanced symptoms include abnormal brain wave patterns and convulsions. Pyridoxine Deficiency Alcohol contributes to the destruction and loss of vitamin B6 from the body. ○ When the body breaks down alcohol, it produces acetaldehyde. ○ If allowed to accumulate, acetaldehyde dislodges the PLP coenzyme from its enzymes; once loose, PLP breaks down and is excreted.  Pyridoxine Deficiency Another drug that acts as a vitamin B6 antagonist is isoniazid, a medication that inhibits the growth of the tuberculosis bacterium. This drug has saved countless lives, but because isoniazid binds and inactivates vitamin B6, it can induce a deficiency. Whenever isoniazid is used to treat tuberculosis, vitamin B6 supplements must be given to protect against deficiency. Information is limited, but vitamin B6 bioavailability from plant- derived foods seems to be lower than from animal derived foods. Fiber does not appear to interfere with vitamin B6 absorption. Pyridoxine Toxicity The first major report of vitamin B6 toxicity appeared in the early 1980s. Until that time, most researchers and dietitians believed that, like the other water-soluble vitamins, vitamin B6 could not reach toxic concentrations in the body. The report described neurological damage in people who had been taking more than 2 grams of vitamin B6 daily (20 times the current UL of 100 milligrams per day) for 2 months or more. Pyrodoxine RDA 1.3 mg adult Significant role in protein metabolism Deficiency disease: Depression, anemia Toxicity disease: Nerve damage Pyridoxine in Foods Rich sources: Chicken Banana Watermelon Pyridoxine Review Biotin (Vitamin B7) Coenzyme in metabolism Delivers carbon to pyruvate to form oxaloacetate (the 4-carbon compound needed to combine with acetyl CoA to keep the TCA cycle turning). The biotin coenzyme also participates in gluconeogenesis, fatty acid synthesis, and the breakdown of certain fatty acids and amino acids. Biotin is commonly associated with healthy skin, hair, and nails. It supports the structure of keratin, a protein found in these tissues. Biotin (Vitamin B7) Widespread in food Biotin is needed in very small amounts. Because there is insufficient research on biotin requirements, an Adequate Intake (AI) has been determined, instead of an RDA. Some biotin is also synthesized by GI tract bacteria, but this amount does not contribute much to the biotin absorbed. Toxicity ○ No UL Biotin Overview