Topic Wise Notes: Nutrition
Please note: The answers provided below, are just for reference. Always consult your college professor if you have any queries.
Q.1. Discuss the importance of food in maintaining good health.
What we eat provides all the essential nutrients to our body. This supplies our body with the right amount of energy to do our daily work. And all these nutrients come only from healthy food, not anything and everything we eat.
Healthy food is needed to stimulate the growth hormones that will increase our height gradually with age.
Healthy food is also needed for the functioning of our system. All the nutrients derived from healthy food trigger body cells and brain cells to actively run and perform their task.
Healthy food improves the immune system, preventing you from falling sick easily. A strong immunity fights against all disease bearing bacteria and viruses.
It is generally advised to cut out fat from our diet. This is often mistaken as entirely excluding even healthy fats. The unhealthy fats that should not be eaten are called saturated, and trans- fats. Mono unsaturated fats, poly unsaturated fats, omega 3 and omega 6 fatty acids are very important for our health, just like proteins and vitamins. These fats get stored under skin cells which get transformed into energy required for physical and mental activities. It is important that we include these in our diet.
Healthy food can help you maintain a well-shaped body without falling into the evil trap of weight gain or obesity.
OR Classify nutrients and explain them briefly.
Nutrients are compounds in foods essential to life and health, providing us with energy, the building blocks for repair and growth and substances necessary to regulate chemical processes.
Classification of Nutrients
Based on requirements by body nutrients are classified into two categories:
Both are equally important for good health. The amount needed to ensure good health varies from individual to individual depending on their age, gender, body size, activity and state of health. ICMR gives the RDA for Indians.
Macronutrients are consumed in relatively large amounts, macronutrients are used primarily to generate energy or to incorporate into tissues for growth and repair.
Macronutrients: Carbohydrates: pasta, rice, cereals, bread, potatoes, milk, fruit, sugar Proteins: meat, dairy, legumes, nuts, seafood, and eggs Fats: oils, butter, margarine, nuts, seeds, avocados and olives, meat and seafood Water: An adult needs about 2–3 liters of water each day.
Micronutrients are needed in smaller amounts they have subtle biochemical and physiological roles in cellular processes, like vascular functions or nerve conduction.
Minerals are the substances that people need to ensure the health and correct working of their soft tissues, fluids, and their skeleton. Examples of minerals include calcium, iron, iodine, fluorine, phosphorus, potassium, zinc, selenium, and sodium.
Vitamins are also called protective foods.
Vitamins are further classified into two groups: Fat-soluble vitamins: vitamins A, D, E, and K are soluble in fats and fat solvents. They are insoluble in water. So these are utilized only if there is enough fat in the body. Water-soluble vitamins: vitamins B and C, and folic acid are soluble in water and so they cannot be stored in the body.
Q.2. Define Energy. Discuss the varioius factors affecting energy requirements.
Energy is defined as the ability to do work. The first and foremost function of food is to supply energy to the body. When food is digested, the complex nutrient like carbohydrates, fat and proteins are broken down into monosaccharide, fatty acids+ glycerol and amino acids respectively. These simple forms are absorbed into the bloodstream and supplied to the millions of cell in the body to be oxidized to release energy.
Factors Contributing To Energy Requirement
The total energy required by a person is sum total of basal energy needs, activity. Energy is needed for growth, for maintenance, for many processes continuously taking place, for maintaining body temperature and for physical and mental activity.
Activities that need energy are:
Voluntary activities – activities which are under ones control such as walking, sitting.
Involuntary activities – these activities which take place by body itself. They are not under our control, thus vital for our survival eg. Body temperature, heartbeat,
These involuntary activities need energy and referred to as basal metabolism
Total energy needed by body = Basal Metabolic Rate + Specific Dynamic Action + Physical activity
The amount of energy required by the body for carrying out involuntary work is known as basal metabolic rate (BMR)
The involuntary work includes the functioning of various organs and systems which continuously to keep body processes going such as heart and blood circulation.
Q.3. What are the functions of Carbohydrates in our body?
There are five primary functions of carbohydrates in the human body. They are energy production, energy storage, building macromolecules, sparing protein, and assisting in lipid metabolism.
The primary role of carbohydrates is to supply energy to all cells in the body. Many cells prefer glucose as a source of energy versus other compounds like fatty acids. Some cells, such as red blood cells, are only able to produce cellular energy from glucose. The brain is also highly sensitive to low blood-glucose levels because it uses only glucose to produce energy and function (unless under extreme starvation conditions). About 70 percent of the glucose entering the body from digestion is redistributed (by the liver) back into the blood for use by other tissues. Cells that require energy remove the glucose from the blood with a transport protein in their membranes.
If the body already has enough energy to support its functions, the excess glucose is stored as glycogen (the majority of which is stored in the muscles and liver). A molecule of glycogen may contain in excess of fifty thousand single glucose units and is highly branched, allowing for the rapid dissemination of glucose when it is needed to make cellular energy. The amount of glycogen in the body at any one time is equivalent to about 4,000 kilocalories—3,000 in muscle tissue and 1,000 in the liver. Prolonged muscle use (such as exercise for longer than a few hours) can deplete the glycogen energy reserve.
Although most absorbed glucose is used to make energy, some glucose is converted to ribose and deoxyribose, which are essential building blocks of important macromolecules, such as RNA, DNA, and ATP. Glucose is additionally utilized to make the molecule NADPH, which is important for protection against oxidative stress and is used in many other chemical reactions in the body. If all of the energy, glycogen-storing capacity, and building needs of the body are met, excess glucose can be used to make fat. This is why a diet too high in carbohydrates and calories can add-on the fat pounds.
In a situation where there is not enough glucose to meet the body’s needs, glucose is synthesized from amino acids. Because there is no storage molecule of amino acids, this process requires the destruction of proteins, primarily from muscle tissue. The presence of adequate glucose basically spares the breakdown of proteins from being used to make glucose needed by the body.
As blood-glucose levels rise, the use of lipids as an energy source is inhibited. Thus, glucose additionally has a “fat-sparing” effect. This is because an increase in blood glucose stimulates the release of the hormone insulin, which tells cells to use glucose (instead of lipids) to make energy. Adequate glucose levels in the blood also prevent the development of ketosis. Ketosis is a metabolic condition resulting from an elevation of ketone bodies in the blood. Ketone bodies are an alternative energy source that cells can use when glucose supply is insufficient, such as during fasting. Ketone bodies are acidic and high elevations in the blood can cause it to become too acidic.
Glucose is indispensable for the maintenance of the integrity of nervous tissue (some central nervous system areas are able to use only glucose for energy production) and red blood cells.
They take part in detoxifying processes. For example, at hepatic level glucuronic acid, synthesized from glucose, combines with endogenous substances, like hormones, bilirubin, etc., and exogenous substances, like chemical or bacterial toxins or drugs, making them atoxic, increasing their solubility and allowing their elimination.
They are also found linked to many proteins and lipids. Within cells, they act as signals that determine the metabolic fate or the intracellular localization of the molecules which are bound. On the cellular surface, their presence is necessary for identification processes between cells that are involved e.g. in the recognition between spermatozoon and oocyte during fertilization, in the return of lymphocytes in the lymph nodes of provenance or still in the leukocyte adhesion to the lips of the lesion of a blood vessel.
Two homopolysaccharides, cellulose and chitin (probably, next to cellulose, the second most abundant polysaccharide in nature), serve as structural elements, respectively, in plant cell walls and exoskeletons of nearly a million species of arthropods (e.g. insects, lobsters, and crabs).
Heteropolysaccharides provide extracellular support for organisms of all kingdoms: in bacteria, the rigid layer of the cell wall is composed in part of a heteropolysaccharide contained two alternating monosaccharide units while in animals the extracellular space is occupied by several types of heteropolysaccharides, which form a matrix with numerous functions, as hold individual cells together and provide protection, support, and shape to cells, tissues, and organs.
OR Illustrate the role of dietary fibre in human diet.
Dietary fiber is a type of carbohydrate that cannot be digested by our bodies’ enzymes. It is found in edible plant foods such as cereals, fruits, vegetables, dried peas, nuts, lentils, and grains. Fiber is grouped by its physical properties and is called soluble, insoluble or resistant starch. All three types of fiber have important roles to play.
Significance of Dietary fiber
Fiber helps to keep our digestive system healthy and helps to prevent constipation. For example, fiber bulks up stools, make stools softer and easier to pass and make the waste move through the digestive tract more quickly.
Cardiovascular disease (heart disease and stroke) and type 2 diabetes: Foods such as oats and barley contain a type of fiber known as beta-glucan, which may help to reduce cholesterol levels if you consume 3g or more of it daily, as part of a healthy diet.
Research has increasingly shown how important the bacteria in our gut may be to our health, and it has been suggested that a fiber-rich diet can help increase the good bacteria in the gut. Some fiber types provide a food source for ‘friendly’ gut bacteria helping them to increase and produce substances that are thought to be protective such as short-chain fatty acids.
Dietary fiber play role in energy intake control and reduced risk for the development of obesity. The role of dietary fiber in energy intake regulation and obesity development is related to its unique physical and chemical properties that aid in early signals of satiation and enhanced or prolonged signals of satiety.
Adds bulk to the diet, making feel full faster
May reduce appetite
Attracts water and turns to gel during digestion, trapping carbohydrates and slowing absorption of glucose
Lowers variance in blood sugar levels
Lowers total and LDL cholesterol
Reduces risk of heart disease
Regulates blood pressure
May reduce onset risk or symptoms of metabolic syndrome and diabetes
Speeds the passage of foods through the digestive system
Adds bulk to stool
Balances intestinal pH and stimulates intestinal fermentation production of short-chain fatty acids
May reduce risk of colorectal cancers
Sources of Dietary Fiber
Fiber-rich foods include: Wholegrain breakfast cereals, wholewheat pasta, wholegrain bread and oats, barley and rye Fruit such as berries, pears, melon and oranges Vegetables such as broccoli, carrots, and sweetcorn Peas, beans, and pulses Nuts and seeds Potatoes with skin
Q.4. Classify Vitamins and explain the significance of Vitamin-A and D.
Vitamins are organic molecules that are essential for normal health and growth. They are required in trace amounts and must be obtained from the diet because they are not synthesized in the body.
Organic molecules with a wide variety of functions.
Cofactors for enzymatic reactions
Before vitamins were discovered, it was known that lime juice prevented the disease scurvy in sailors and that cod liver oil could prevent rickets. In 1912, scientists found that, in addition to carbohydrates, fats, and proteins, certain other factors called vitamins must be obtained from the diet.
Two distinct types:
water-soluble vitamin is one that dissolves in water and as a result, is easily absorbed into the tissues of the body and metabolized more quickly than fat-soluble vitamins.
The fat soluble vitamins are soluble in lipids (fats). These vitamins are usually absorbed in fat globules that travel through the lymphatic system of the small intestines and into the general blood circulation within the body.
vitamin A; includes retinol, retinal, retinyl esters, and retinoic acid and is also referred to as “preformed” vitamin A. Beta carotene can easily be converted to vitamin A as needed.
Function: Essential for vision Lycopene may lower prostate cancer risk. Keeps tissues and skin healthy. Plays an important role in bone growth and the immune system. Diets rich in the carotenoids alpha-carotene and lycopene seem to lower lung cancer risk. Carotenoids act as antioxidants. Foods rich in the carotenoids lutein and zeaxanthin may protect against cataracts.
Food Sources: Sources of retinoids: beef liver, eggs, shrimp, fish, fortified milk, butter, cheddar cheese, Swiss cheese Sources of beta carotene: sweet potatoes, carrots, pumpkins, squash, spinach, mangoes, turnip greens, and almost all green vegetables.
Deficiency: Deficiency of Vitamin A called Night Blindness.
Calciferol (vitamin D)
Function: It helps to maintain normal blood levels of calcium and phosphorus, which strengthens bones. It helps in the formation of teeth and bones. Supplements can reduce the number of non-spinal fractures.
Food Sources: Fortified milk or margarine, fortified cereals, fatty fish
Deficiency: Deficiency can result in weakened bones.
OR Define and classify proteins. Suggest methods to improve their quality.
Protein is the basic material of every living cell. It is the only nutrient that can make new cells and rebuild tissues. Therefore, an adequate amount of protein in the diet is essential for normal growth and development and the maintenance of health.
On the basis of protein composition
Simple Protein– comprises of only amino acid eg. Albumin, globulin
Conjugated Protein– comprises of amino acids and a non protein group. Eg. haemoglobin
Derived Protein– these are proteins derived by partial to complete hydrolysis from the simple or conjugated proteins by the action of acids, alkalis and enzymes. Eg. peptones
On the basis of their quality( i.e. amino acids present in them)
Complete proteins – these proteins contain all essential amino acids in sufficient proportion and amount to meet the body’s growth need and for repair of tissue cells. Complete protein food have high biological value (BV). It is defined as the amount of absorbed nitrogen retained in the body. Eg. – egg, milk, meat.
Partially complete proteins : those proteins in which one or more essential amino acids are present in inadequate amounts. They cannot synthesize tissues but can maintain life. Found in plant foods- like cereals. Pulses, nuts, oilseeds. A combination of one incomplete protein with other in diet can provide increased amount of essential amino acids. Eg. Cereals are deficient in lysine and pulses are deficient in methionine.
Incomplete proteins : in these one or more essential amino acids are completely lacking. Thus these proteins are incapable of growth and repair of body cells. They cannot maintain life. Eg. Gelatin, zein in corn.
ESSENTIAL AMINO ACIDS are essential to maintain life. These cannot be synthesized in our body thus required through diet.
Methods of improving protein quality
Animal protein contains all essential amino acids in correct proportions and amounts and is good quality proteins. Four essential amino acids are in short supply in plant proteins. They are lysine, methionine, threonine, and tryptophan. Proteins in plant foods are generally deficient in one or two essential amino acids. Cereals are poor in lysine and pulses are poor in methionine.
Protein will be synthesized only when all amino acids, which form the protein, are present simultaneously. Vegetable proteins are partially complete proteins. These two points should be kept in mind while improving the protein quality of a meal.
The protein quality of a mainly vegetarian diet can be improved in the following ways.
By including a small quantity of complete protein food in every meal. Complete protein foods such as milk, curds, paneer, cheese, buttermilk, and eggs could be used in small quantities in various preparations instead of including it in one meal only, e.g. cereal and milk, egg or cheese sandwiches, french toast, raitha, curd rice, or buttermilk at all meals in place of bowl of curd in one meal.
Correct mixtures of plant foods could provide all essential amino acids in suitable proportions and amounts. Cereal and pulse combinations will complement each other as cereals provide methionine, which is lacking in pulses, and pulses provide lysine, which is lacking in cereals, when cereal and pulses are consumed together in the same meal, e.g. missie roti, Thalipeeth, Puran Poli, idli, and Rajma Chawal. This is possible because the same amino acids are not missing from all plant foods.
Synthetic amino acids may be added to processed foods to compensate for the amino acid deficient in them, e.g., lysine enriched bread. Textured vegetable proteins are used successfully to improve protein quality and reduce the cost of protein-rich foods.
When plant proteins are consumed with a small quantity of animal protein, the quality of the mixture is likely to be as effective as if the only animal protein has been consumed. A good rule while planning menus would be to include some animal proteins at each meal instead of concentrating it all in one meal.
Q.5. Enlist the various functions of water in maintaining good health.
Water quenched our thirst and is the most refreshing & cooling of all liquids.
It is a structural component of all cells.
Water is a medium in which all chemical reaction takes place.
It is an essential component of all body fluid such as blood, cerebrospinal fluid, bile, digestive fluid, urine.
It acts as a lubricant & helps us in swallowing food or to digest food.
It acts as a solvent for the products of digestion & helps in transporting this product in different parts of the body.
It regulates body temperature.
It helps to throw the waste product from the body.
OR Define invisible source of water. How water balance is maintained in the body?
Invisible water that is inside the food s & metabolic water.
n a normal individual, the maintenance of water balance is archived by adjusting both water intake & excretion as needed. The major inputs of water are:
Fluids that we consume as beverages, including water depending on climatic conditions & habits.
Different types of foods & fruits that we take in solid form.
Output or loss of water from the body:
Renal loss: Kidneys excrete about 1-2 liter of water daily
Skin: The water loss from the skin is through perspiration.
Intestine: A small quantity of water is normally losses in feces.
Lungs: The air expired from the lungs also contains water.
Sweat: It depends on physical activity & environmental conditions.
Daily intake & output of water
The fluid we take
Q.6. “Balanced diet is important to live a healthy life”. How far do you agree with this statement?
The statement is true. The below mentioned points support the statement :
Balanced diet includes a variety of food items from all the food groups.
It meets the RDA for all nutrients
It provides safety allowances to withstand the short duration of illness.
To maintain a state of positive health and optimal performance.
Prevents deficiency diseases.
Promotes and preserves health.
Promotes optimum nutrition thus maintains acceptable body dimensions.
Q.7. What are the various factors that affect Menu Planning in relation to nutrition?
The major objective of planning meals is to achieve nutritional adequacy along with the consideration of food availability, food habits, food preferences, purchasing power and many other factors.
The first prerequisite of a good meal plan is to meet the nutritional needs of the individual and the family as a whole. No single food can meet all the nutrient requirements. A combination of different foods needs to be included in the diet.
For convenience in meal panning, different foods have to be been grouped under three food groups based on their function and major nutrient contributions. Body Building Foods, Energy Giving and Protective Foods
ENERGY GIVING FOODS
This group includes foods rich in carbohydrate like cereals and their products, starchy roots and tubers and sugar and those rich in fat like nuts, fats and oils. Therefore the energy in our diet is mainly contributed by this group.
Cereals and nuts in addition to energy, contribute significant amount of proteins, minerals and B group vitamins.
Fats sugars besides being energy dense and palatability to the diet.
BODY BUILDING FOODS
This group includes food which provides proteins that are important for tissue building and maintenance.
Foods of animal origin like milk and its product, eggs, meat, fish, provide proteins of good quality.
Plant protein foods like pulses, legumes nuts and oilseeds have a relatively inferior quality of protein.
The foods of this group in addition to protein also contribute energy, vitamin A, vitamins of B groups and minerals.
This group includes foods that provides ample amount of vitamins and minerals for protective regulatory function of the body.
All vegetables and fruits (except starchy roots and tubers) and fruits comprise this group.
Amongst vegetables most of the GLV’S are good source of iron, calcium, beta carotene, vitamin C and dietary fibre.
Deep yellow and orange colored fruits and vegetables are particularly rich in beta carotene and citrus fruits in vitamin C.
Hence, selection and inclusion of some foods from each of these food groups in every meal is important to provide all the essential nutrients for various body functions and to make the diet well balanced.
The nutrient needs of each member of the family depend upon age, sex, activity, physiological stress etc. Modification is done in same meal for different individuals.
Q.8. Discuss the fast food trend in the food service industry, with reference to nutrition and health.
Nutritive Value Of Fast Food And Junk Food
The fast-food industry is growing rapidly all over the world to provide a quick meal to the customer at an unaffordable cost and in very little time. In India, the fast-food industry comprises mainly of south Indian, Punjabi snacks and popular MNCs like KFC, MC’D, Pizza hut, etc. Many products have been modified to suit the Indian palate and respect religious sentiments. Many of these providers take away or drive-thru services as well as a sitting area to eat food on the premises. Modern commercial fast food is often highly processed & prepared & industrial fashion. Most items on the menu are prepared at the central supply facility & then shipped to individual outlets where they are reheated/cooked or assembled in a short time. The central kitchen ensures consistency in product quality & ability to deliver the order quickly to the customer eliminating labor & equipment cost in the individual restaurant.
Q.9. What measures should be taken in mass food production to retain maximum nutritive value of food?
Wash vegetables , fruits and rice in just sufficient amount of water. It is advisable either to cook in a minimum amount of water or to use cooking water in soups and gravies.
Cutting vegetables to small pieces and exposing them to air before cooking leads to loss of vitamins particularly vitamin C. thus it is advisable to cut large pieces and cook for shorter period of time.
The 3 R’s of cooking to conserve nutrients are:
Reduce the amount of water
Reduce the length of cooking period
Reduce the amount of surface area exposed
Oil heated repeatedly should not be consumed as repeated heating during frying leads to production of toxic substances due to pre oxidation and rancidity.
Q.10. State True or False:
(a) Another name for Vitamin-A is Thiamine. False (b) Energy is defined as the capacity for doing work. True (c) Coffee is an invisible source of water. False (d) Lactose sugar is found in milk. True (e) 1-gram of protein gives 4-Kcal when oxidised in the body. True (f) Pyridoxine deficiency causes Pellagra. False (g) Amla is a good source of Vitamin-C. True (h) Deficiency of iodine results in goitre. True (i) Fats are classified under micronutrients. False (j) Vitamin-B is soluble in water. True
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