FOOD COMPOSITION Food is any substance eaten or drunk to provide nutritional support for the body or for pleasure. Food is ingested by an organism to Produce energy Stimulate growth Maintain life
FOOD COMPOSITION Food, originating from plant or animal origin, usually contains the following essential nutrients, such as – 1.CARBOHYDRATES 2.FATS 3.PROTEINS 4.VITAMINS 5.MINERALS 6.WATER 7.FIBER
FOOD COMPOSITION MACRONUTRIENTSMICRONUTIENTS CARBOHYDRTAESVITAMINS FATSMINERALS PROTEINSTRACE ELEMENTS
MICRONUTRIENTS Micronutrients are nutrients that are required in small amounts for our growth and development. Micronutrients include – VITAMINS & MINERALS Microminerals – Needed in amounts less than 100mg/day VITAMINSMINERALSTRACE ELEMENTS Vitamin A (Retinol)MgZn Vitamin B complexCaMg Vitamin C (Ascorbic acid) KCu Vitamin DPCr Vitamin E (Tocopherol) Vitamin K
MICRONUTRIENT DEFICIENCY Micronutrient deficiencies are widespread affecting approximately 2 billion people worldwide. Some of the common deficiencies are due to lack of iron, iodine and vitamin A. Micronutrient deficiencies are commonly associated with chronic hunger, in addition to specific dietary deficits. The most common deficiencies in school-age children are due to lack of iron, vitamin A and iodine. IRON DEFICIENCY – Retards physical growth and mental development. It may also lead to anemia. It also impairs immune function and increases the risk of infections. IODINE DEFICIENCY – Brain damage and significantly lower IQ. VITAMIN A DEFICIENCY - Retards physical growth and may also cause blindness.
CARBOHYDRATES Carbohydrates are organic compounds consisting of carbon (C), hydrogen (H) and oxygen (O) atoms with the empirical formula C m (H 2 O) n (where m could be different from n). Example : glucose, fructose, sucrose, lactose and starch Structurally however, it is more accurate to view them as polyhydroxy aldehydes and ketones.
CARBOHYDRATES Monosaccharides are the simplest carbohydrates in that they cannot be hydrolyzed to smaller carbohydrates. They are aldehydes or ketones with two or more hydroxyl groups. Examples of monosaccharides include glucose, fructose, galactose, xylose and ribose.
A disaccharide is a type of carbohydrate consisting of two monosaccharides (simple sugars) linked together by covalent bonds. Common nutritionally important disaccharides are sucrose, lactose, and maltose. Sucrose = Glucose + Fructose Lactose = Glucose + Galactose Maltose = Glucose + Glucose
An oligosaccharide is a saccharide polymer containing a small number (typically 3 to 10) of component sugars, also known as simple sugars. Oligosaccharides can have many functions; for example, they are commonly found on the plasma membrane of animal cells where they can play a role in cell-cell recognition ( The process in which a cell recognizes or identifies its environment )
Polysaccharides are polymeric carbohydrate structures, formed of repeating units joined together by glycosidic bonds. These structures are often linear, but may contain various degrees of branching. E.g. storage polysaccharides (starch and glycogen), structural polysaccharides (cellulose and chitin).
Functions of carbohydrates: 1.The primary function of carbohydrates are to provide energy to living organisms. 2.Carbohydrates spare protein so that protein can concentrate on building, repairing, and maintaining body tissues instead of being used up as an energy source. 3.Carbohydrate is necessary for the regulation of nerve tissue and is the ONLY source of energy for the brain. 4.Some carbohydrates are high in fiber, which helps prevent constipation and lowers the risk for certain diseases such as cancer, heart disease and diabetes. 5.Carbohydrates are used as sweeteners.
Standard Daily Carbohydrate Requirements for Men and Women: It's guesstimated that many women need 1,600 to 2,200 calories daily, whereas active men need about 2,800 calories a day. The nutrition community currently advices that around 55 to 60 percent of your daily calories come from carbohydrates. Since it's also recommended that you choose a diet that's moderate in sugar (one source of carbohydrates), your plate should lean toward more complex carbohydrate food sources, such as whole grains, cereals, fruits and vegetables.
Fats & oils: Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. Chemically, fats are generally triesters of glycerol and fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure and composition.
Although the words "oils", "fats", and "lipids" are all used to refer to fats, "oils" is usually used to refer to fats that are liquids at normal room temperature, while "fats" is usually used to refer to fats that are solids at normal room temperature. "Lipids" is used to refer to both liquid and solid fats, along with other related substances (fats, waxes, sterols, fat-soluble vitamins, monoglycerides, diglycerides, phospholipids, and others). Examples of edible animal fats are lard (pig fat), fish oil, and butter or ghee. They are obtained from fats in the milk, meat and under the skin of the animal. Examples of edible plant fats are peanut, soya bean, sunflower, sesame, coconut, olive, and vegetable oils.
Lipids are of three main types: a)Simple lipids b)Compound lipids c)Derived lipids Simple lipids (also called neutral lipids) are esters of fatty acids with alcohols. These includes fats, which are esters of fatty acids with glycerol & waxes, which are esters of fatty acids with alcohols other than glycerol. Compound lipids contain other groups in addition to the esters. Examples of compound lipids are: phosphatides (phospholipids) contains phosphoric acid and a nitrogen moiety, cerebrosides (glycolipids) containing fatty acids, carbohydrates and a nitrogen moiety.
Derived lipids are substances derived from neutral or compound lipids and have general properties of lipids. These includes fatty acids, higher alcohols & sterols etc. Role of fats & oils in biological systems: 1. Most concentrated source of food energy. They provide 9 kcal/g. They act as energy storage in seeds, fruits and in animals. 2. Carriers of fat soluble vitamins. 3. Triglycerides, phospholipids, cholesterol and cholesterol esters are important to the structure, and permeability of membranes and cell walls. 4. Major component of adipose tissue, which serves as thermal insulator for body, protect body against shock, contribute to body shape.
Saturated fatty acids The fatty acids that contain only C-C bonds, remain closely packed and usually are solid at room temperature are called saturated fatty acids. E.g. Butter, Fat seen in processed meats Unsaturated fatty acids The fatty acids that contain one or more double C=C bonds and are non-linear chains that do not allow molecules to pack closely together are called unsaturated fatty acids. They are liquid in room temperature. Unsaturated fatty acids can be further divided to monounsaturated fatty acids and polyunsaturated fatty acids.
Dietary sources of fats & oils 1) Polyunsaturated Fats - lowers blood cholesterol and encourages heart health:- Good food sources are; Vegetable oils such as safflower, soy bean, sunflower, fish oils, naturally present in fish, seeds and most nuts. Omega-3 fats are a type of polyunsaturated fat found mainly in oily fish (e.g.- salmon,, sardines, herrings), canola oil, flaxseed oil (linseed oil) and walnut oil. These fats help to reduce blood clotting, blood pressure and blood fat levels. 2) Monounsaturated Fats - do not raise blood cholesterol and encourages heart health Good food source are- peanuts, olive oil, olives and canola oil, almond and hazelnuts
3) Saturated Fats - raise blood cholesterol and promote heart disease, these are the ones to reduce or avoid Major food sources are- dairy fats such as butter, clarified butter, cultured butter, butter/margarine mix, cream, meat fats such as lard, beef, white visible fat on beef etc. Trans fatty acids Most trans-isomer fats (commonly called trans fats) are commercially produced rather than naturally occurring. Research suggests that amounts of trans fats correlate with circulatory diseases such as atherosclerosis and coronary heart disease. Trans fats, just like saturated fats, raise the LDL ("bad") cholesterol and lowers the HDL ("good") cholesterol.
Essential fatty acids: Essential fatty acids, or EFAs, are fatty acids that humans and other animals must ingest for good health because the body requires them but can't make them from other food components. There are only two EFAs: alpha-linolenic acid, an omega-3 fatty acid, and linoleic acid, an omega-6 fatty acid. Omega-3 fatty acids: n3 fatty acids (omega-3 fatty acids) are a family of unsaturated fatty acids that have in common a final carbon-carbon double bond in the n3 position; that is, the third bond from the methyl end of the fatty acid. Nutritionally important n3 fatty acids include α-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA)
Potential health benefits of Omega-3 fatty acids 1) They were essential to normal growth in young children and animals. 2) The omega-3 fatty acid, EPA, appears to form potent anti-inflammatory molecules, called resolvins and omega-3-oxylipins, which may partly explain the positive effects of fish oil. 3) There is scientific evidence that omega-3 fatty acids reduce blood triglyceride levels and regular intake may reduce the risk of heart attack. 4) Some potential benefits have been reported in conditions such as rheumatoid arthritis and cardiac arrhythmias. 5) Several studies report possible anti-cancer effects (particularly breast, colon, and prostate cancer).
Dietary sources of n 3 fatty acids (Animal): The most widely available source of EPA and DHA is cold water oily fish such as salmon, herring, and sardines.Although fish is a dietary source of n3 fatty acids, fish do not synthesize them; they obtain them from the algae (microalgae in particular) or plankton in their diet. Dietary sources of n3 fatty acids (Plant): Flax seeds produce linseed oil, which has a very high n3 content. Six times richer than most fish oils in n3, flax (or linseed) and its oil are perhaps the most widely available botanical source of n3.
Omega-6 fatty acids: n6 fatty acids (omega-6 fatty acids) are a family of unsaturated fatty acids that have in common a final carbon- carbon double bond in the n6 position, that is, the sixth bond, counting from the end opposite the carboxyl group. Dietary source : Poultry Nuts Cereals Most vegetable oils
Negative health effects: Excessive levels of omega6 fatty acids may increase the probability of a number of diseases and depression. Excess omega6 fats interfere with the health benefits of omega3 fats, in part because they compete for the same rate-limiting enzymes. Chronic excessive production of omega 6 eicosanoids is associated with heart attacks, thrombotic stroke, arrhythmia, arthritis, osteoporosis, inflammation, mood disorders, obesity and cancer. A high consumption of omega-6 polyunsaturated fatty acids, which are found in most types of vegetable oil, may increase the likelihood that postmenopausal women will develop breast cancer. Similar effect was observed on prostate cancer.
Proteins Proteins (also known as polypeptides ) are organic compounds made of amino acids arranged in a linear chain and folded into a 3D form. The amino acids in a polymer are joined together by the peptide bonds between the carboxyl and amino groups of adjacent amino acid residues. The sequence of amino acids in a protein is defined by the sequence of a gene, which is encoded in the genetic code.
Functions: 1)Structural proteins confer stiffness and rigidity 2)Takes part in repair and maintenance of the body 3)Contractile Proteins - are responsible for movement. Examples include actin and myosin. 4)Enzymes - are proteins that facilitate biochemical reactions. 5)Hormonal Proteins - are messenger proteins which help to coordinate certain bodily activities. Examples include insulin and oxytocin. 6)Transport Proteins - are carrier proteins which move molecules from one place to another around the body. Examples include hemoglobin.
Dietary requirements of proteins According to US & Canadian Dietary Reference Intake guidelines, women aged 19–70 need to consume 46 grams of protein per day, while men aged 19–70 need to consume 56 grams of protein per day to avoid a deficiency. Essential amino acids The essential amino acids are those which can not be synthesized within the body. These include leucine, isoleucine, valine, lysine, threonine, typtophan, methionine, phenylalanine and histidine.
Protein Deficiency : Protein deficiency is a serious cause of ill health and death in developing countries. 1. Marasmus: Marasmus is a disease caused by a severe deficiency of protein and calories that affect infants and very young children, often resulting in weight loss and dehydration. Marasmus can develop into starvation and cause fatality caused by a lack of essential nutrients.
2. Kwashiorkor: Kwashiorkor is a disease caused by a severe deficiency of protein in diets that contain calories mostly from carbohydrates such as yams, rice and bananas. It usually affects older children. People with kwashiorkor appear puffy in the abdomen area from retention of fluid.
3. Protein deficiency can lead to reduced intelligence or mental retardation. 4. If enough energy is not taken in through diet, the body will use protein from the muscle mass to meet its energy needs, leading to muscle wasting over time. 5. If the individual does not consume adequate protein in nutrition, then muscle will also waste as more vital cellular processes (e.g. respiration enzymes, blood cells) recycle muscle protein for their own requirements.
Vitamins Vitamins are any of a group of substances that are essential, in small quantities, for the normal functioning of metabolism in the body. They cannot usually be synthesized in the body but they occur naturally in certain foods. Insufficient supply of any particular vitamin results in a deficiency disease. Thirteen vitamins are presently universally recognized. They are vitamins A, C, D, E, K and the B vitamins (thiamine, riboflavin, niacin, pantothenic acid, biotin, vitamin B-6, vitamin B-12 and folate). VITAMINVITAMIN DEFICIENCY A B1 C D E K
Types of minerals There are two groups of minerals, Macro minerals and trace minerals. Macro minerals are needed in the diet in amounts of 100 milligrams (mg) or more each day. They include calcium, magnesium, sodium, potassium, phosphorus and chlorine. Macro minerals are present in virtually all cells of the body, maintaining general homeostasis and required for normal functioning.
Microminerals (also known as trace minerals) are micronutrients that are chemical elements. They include at least iron, cobalt, chromium, copper, iodine, manganese, selenium, zinc, and molybdenum. They are dietary minerals needed by the human body in very small quantities (generally less than 100mg/day) as opposed to macrominerals which are required in larger quantities.
FUNCTIONS Minerals help regulate body processes, such as in enzyme systems. Minerals function in nerve impulse transmission. Calcium and phosphorous are important in bone structure and growth; Potassium and sodium for electrolyte balance Iron for oxygen transport. Some enzymes need metal ions obtained from minerals to aid chemical reactions in the body. Humans require iodine for proper physical and mental development. Magnesium is used by the body to help maintain muscles, nerves, and bones. Potassium works with sodium to maintain the body's water balance. Selenium is incorporated into proteins to make selenoproteins, which are important antioxidant enzymes. Zinc functions as an antioxidant and is involved in many critical biochemical reactions.
Dietary fibers & fiber like ingredients Dietary fiber, also known as roughage or bulk, includes all parts of plant foods that your body can't digest or absorb. Unlike other food components, such as fats, proteins or carbohydrates which your body breaks down and absorbs fiber isn't digested by your body. Instead, it passes relatively intact through your stomach, small intestine, colon and out of your body.
Fiber is commonly classified as soluble (it dissolves in water) or insoluble (it doesn't dissolve): Soluble fiber. This type of fiber dissolves in water to form a gel-like material. It can help lower blood cholesterol and glucose levels. Soluble fiber is found in oats, peas, beans, apples, citrus fruits, carrots, barley and psyllium. Insoluble fiber. This type of fiber promotes the movement of material through your digestive system and increases stool bulk, so it can be of benefit to those who struggle with constipation or irregular stools. Whole-wheat flour, wheat bran, nuts, beans and vegetables, such as cauliflower, green beans and potatoes, are good sources of insoluble fiber.
Benefits of a high-fiber diet A high-fiber diet has many benefits, which include: 1. Normalizes bowel movements. Dietary fiber increases the weight and size of your stool and softens it. A bulky stool is easier to pass, decreasing your chance of constipation. If you have loose, watery stools, fiber may also help to solidify the stool because it absorbs water and adds bulk to stool. 2. Helps maintain bowel health. A high-fiber diet may lower your risk of developing hemorrhoids (piles) and small pouches in your colon. 3. Lowers cholesterol levels. Soluble fiber may help lower total blood cholesterol levels by lowering low-density lipoprotein, or "bad," cholesterol levels. 4. Helps control blood sugar levels. In people with diabetes, fiber particularly soluble fiber can slow the absorption of sugar and help improve blood sugar levels. A healthy diet that includes insoluble fiber may also reduce the risk of developing type 2 diabetes