B5 Micronutrients and Macronutrients

Assessment Objectives B.5.1 Outline the difference between micronutrients and macronutrients. (2) B.5.2 Compare the structures of retinol (vitamin A), calciferol (vitamin D) and ascorbic acid (vitamin C). (3) B.5.3 Deduce whether a vitamin is water- or fat- soluble from its structure. (3) B.5.4 Discuss the causes and effects of nutrient deficiencies in different countries and suggest solutions. (3)

Key Terms Nutrient Metabolism Macronutrient Micronutrient Mineral Vitamin Deficiency Malnutrition

Task As we go through each assessment objective, write the answer to the questions in the worksheet. We will discuss your answers as we finish each objective.

Reference Moodle: Textbook Option B Human Biochemistry. P Moodle: Powerpoint Presentations

B.5.1 Outline the Difference Between Micronutrients and Macronutrients. A nutrient is a substance require by an organism and needed for metabolism – the chemical reactions that occur inside cells. Nutrients include: Carbohydrates Lipids Proteins Vitamins Minerals and Water

Macronutrients The minerals in the first two categories are required in large amounts and are known as macronutrients The quantities required will be in excess of 0.005% of body mass. (for a 75kg male > 375 g) They act as raw materials for the formation of body tissues They provide the necessary chemical environment for cells

Minerals A selection of minerals essential to human health are shown in the following slides. Plants and animals lacking an essential mineral will develop a characteristic disease or disorder Minerals have four functions in the body: They act as raw materials for the formation of body tissues (Calcium for Bone) They provide the necessary chemical environment for cells (Sodium/Potassium for nerves) They act as metabolic intermediates for cell processes (Sulphides in the citric acid cycle) They act as co-enzymes (e.g Fe in Haemoglobin and enzymes also use it to make it)

Some Macronutrient Minerals

Micronutrients Minerals in the last two categories are required in much smaller amounts and are known as micronutrients They are required in miligram or microgram quantities (103 mg = 1g ; 106 μg = 1g) They act as metabolic intermediates for cell processes They act as co-enzymes

Some Micronutrients

B.5.2 Compare the structures of retinol (vitamin A), calciferol (vitamin D) and ascorbic acid (vitamin C). (3) B.5.3 Deduce whether a vitamin is water- or fat-soluble from its structure. (3)

Vitamins are a group of complex organic compounds present in very small quantities in food and absorbed into the body during digestion. They have no energy value, but are essential for a healthy body and for maintaining metabolism

Vitamins Another type of micronutrient are vitamins…….. Vitamins are classified into two groups: Water-soluble (Vitamins C, B) Only stored in small amounts inside cells Must be supplied regularily Fat-soluble (Vitamins A, D, E, K) Stored in the liver and adipose (fat) tissue. The body can hold on until needed.

Vitamins containing C=C double bonds and –OH groups are easily oxidised and keeping food refrigerated slows down this process There are 18 vitamins and minerals essential in a healthy diet. We will focus on 3:

Vitamin A (retinol) The solubility of a vitamin can be deduced from it’s structure. Consider vitamin A (retinol) Polar hydroxyl group (-OH) But is non-polar due to the presence of a large hydrocarbon ‘skeleton.’ Is therefore fat-soluble and largely insoluble in water

Vitamin A It is not easily broken down by cooking It contains only one –OH group It is fat soluble due to its long non-polar hydrocarbon chain Required for the production of rhodopsin> light changes its conformation> creation of nerve impulse> vision

Vitamin A 2 Chemicals: Retinoids and carotenoids Retinoids – body can use right away Carotenoids – body can change it into a retinoid Beta-carotene (Why are carrots good for your eyes? Have you ever seen a rabbit with glasses?) Carotenoids don’t get stored in liver Foods with 25% of your RDA for Vitamin A Cereal 1oz, oatmeal 2.3 cups Fruit: apricots, canteloupe, mango (1/2 c) Veggies: carrots, kale, peas, sweet peppers (1/2 c cooked) Meat: Liver 3oz Milk: 2 cups

Vitamin C In contrast vitamin C is a much smaller molecule with a shorter hydrocarbon ‘skeleton,’ which contains four polar hydroxyl (-OH) groups that can all hydrogen bond Vitamin C is therefore expected to be polar in water

Vitamin C Due to the number of –OH groups this vitamin is soluble in water It is not retained for long in the body A disease known as scorbutus (scurvy) is associated with the lack of this vitamin The symptoms are: swollen legs, rotten gums It was most commonly noticed in sailors who spent long periods of time without fresh food

Vitamins A C and D Use the Structure of Vitamin D to predict whether it is soluble or insoluble in water. Explain…

Vitamin D It is a large hydrocarbon with one –OH group and it is fat soluble A deficiency of vitamin D leads to: bone softening and malformation which is known as rickets

Nutrient Deficiency B.5.4 Discuss the causes and effects of nutrient deficiencies in different countries and suggest solutions. (3) If the body does not contain enough of a vitamin a disorder occurs, which is termed a deficiency disease When intake is insufficient, the deficiency disease can be avoided by supplementing the diet with the necessary vitamin or mineral.

Vitamin A Required for the production of rhodopsin (light-sentistive material in the rods of the retina). Too Little: Nightblindness Xeropthalmia –have difficulty producing tears Effects about 500,000 children in underdeveloped nations Dry mucous membranes Too Much: Makes you think you have a brain tumor Headache, vomiting, nausea, abnormal vision, loss of hair Some precursers can make you turn orange =)

How do we get vitamin A? 2 Chemicals: Retinoids and carotenoids Retinoids – body can use right away Carotenoids – body can change it into a retinoid Beta-carotene (Why are carrots good for your eyes? Have you ever seen a rabbit with glasses?) Carotenoids don’t get stored in liver Foods with 25% of your RDA for Vitamin A Cearal 1oz, oatmeal 2.3 cups Fruit: apricots, canteloupe, mango (1/2 c) Veggies: carrots, kale, peas, sweet peppers (1/2 c cooked) Meat: Liver 3oz Milk: 2 cups

Vitamin D Deficiency Rickets

Scurvy and Vitamin C Deficiency

Pellagra and Vitamin B3 Deficiency

Vitamin C Required for Production of collagen: the protein of connective tissue. Antioxidant Protects immune system, helps fight off infection, reduces allergic reactions Too Little: Scurvy (bleeding gums; tooth loss; mosebleeds; bruising; painful or swollen joints; shortness of breath, increased susceptibility to infection, skin rashes; muscle pains, slow wound healing) Too Much: More than 1000 mcg may cause upset stomach, diarrhea, or constipation

How Do we Get Vitamin C? On the label, look for: Sodium ascorbate Isoacrobate Ascorbic acid Foods with 25% of RDA Cereal: 1 oz Meat: Liver 3oz Fruit: Canteloupe, grapefruit, mango, orange, strawberries, ½ c. Veggies: Asparagus, broccoli, brussel sprouts, kale, kohlrabi, sweet peppers, snow peas (cooked) ½ c. sweet potato: 1 med. Did you know that many foods are preserved with sodium nitrite to prevent the growth of bacteria. At high T, nitrite + protein forms carcinogen. Vitamin C prevents that rxn so it is added to processed meat, too.

Vitamin D Required for the uptake of calcium and phosphorus from food. Too little: can cause weak bones (Rickets) in children In adults: osteomalacia (soft bones, fracture easily) Too much: Kidney stones and hard lumps of calcium in muscles and organs Headache, nausea, vomiting, high blood pressure, retarded physical growth and mental retardation in children, fetal abnormalities

How do we get Vitamin D? 3 forms Calciferol: occurs in fish oils, egg yolks Cholecaliferol: created when sunlight hits skin, reacting with steroids in body fat just underneath skin Ergocalciferol: found in plants Foods with 25% of RDA Salmon or tuna oz Eggs: 3 Milk: 1 cup Some people claim that you should not use sunscreen so that your body can use the sunlight to produce Vitamin D. Most doctors, though, advise getting Vitamin D through your food and wear a high SPF sunscreen at all times.

Cooking and Vitamin Absorption Studies show that cooking foods can cause a decrease in the amount of vitamins in the food Water soluble vitamins dissolve in cooking water Some vitamins are broken down by heating Some vitamins, though, are better than no vitamins. So eat your veggies, cooked or not.

Mineral Deficiencies Deficiency diseases also arise when a person’s diet lacks a specific mineral. Minerals act as: metabolites for various cell processes raw materials for body tissue formation, components of enzymes providing the correct chemical environment for cells

Mineral Deficiency Diseases

Micronutrient Deficiencies Fe anaemia > fatigue I goiter > swallen thyroid gland Vitamin A xerophthalmia & night blindness Vitamin B3 pellagra > diarrhea, dementia, dermatitis Vitamin B1 beriberi > muscles, heart, nerves Vitamin C scurvy > rotten gums Vitamin D rickets > malformation/softening of bones

Some foods are ‘fortified’ to ensure that a normal diet can provide sufficient vitamins or minerals to maintain health For example, the milling of wheat removes part of the grain that’s richest in vitamin B1, so white flour has this vitamin added to it. Margarine has vitamins A and D added Vitamin C is often added to fruit juices and dehydrated mashed potatoes Potassium iodide is commonly added to table salt

Malnutrition is a general term for a medical condition caused by improper or inadequate diets An extended period of malnutrition can result in: Starvation Vitamin or mineral deficiency diseases Infection (since immune system is affected)

Iodine Deficiency Malnutrition caused by a lack of iodine in the diet results in a goitre Due to an over or under active thyroid Is relatively painless but can cause discomfort in movement as it enlarges

Protein Deficiency Protein-energy malnutrition refers to a form of malnutrition where there is inadequate protein intake Kwashiorkor Marasmus

Marasmus (Protein Def) Marasmus is a form of severe protein malnutrition characterized by energy deficiency Leads to extensive tissue and muscle wasting and edema (accumulation of fluid beneath skin) Dry skin, loose skin folds Patients are often irritable and very hungry In children body mass is reduced to less than 80% of normal mass for that height

Kwashiorkor (Protein def) Kwashiorkor is a type of malnutrition commonly believed, in part, to be caused by insufficient protein consumption Children ages 1-4 affected although some adults Swollen abdomen (pot belly) Alternating bands of pale and dark hair Weight loss Dermatitis (inflammation of the skin) and depigmented skin Likely due to deficiency of micronutrients (iron, folic acid, iodine, vit C, antioxidants)

Selenium Deficiencies Human selenium deficiency is rare is many countries but occurs in China where the soil concentration of selenium is low Also found in those that rely on intravenous drip in hospitals as their source of nutrition Gastrointestinal disorders may also decrease absorption of selenium, resulting in depletion Treated with supplements

Genetically Modified Plants Scientists claim that genetically modified (GM) plants can significantly reduce malnutrition, especially in the Third World, through the development of plants that are resistant to pest-derived disease, adverse soil pH or draught conditions. Plants can also be engineered to have a high level of specific nutrients Advantages of GM include: increased yield, reduction in harmful fertilizer use, reduction in machinery and labor costs, etc

Macronutrient Deficiencies Deficiency in macronutrient such as proteins cause marasmus (growth retardation) and kwashiorkor (fatigue, weight loss) Deficiency in Ca produces osteoporosis Deficiency in Na produces cramps

CAUSES OF NUTRIENT DEFICIENCIES Developed world - low income - poor eating habits Developing world - poverty - famine

SOLUTIONS TO COMBAT MALNUTRITION Eating fresh food rich in vitamins and minerals Adding nutrient which that are missing in commonly consumed foods Genetic modification of foods Providing nutritional supplements