4_Food, Nutrition and Health – class 9




Chapter-4                                   Food, Nutrition and Health


Food is an essential source for survival, maintenance, health, growth and development. The components of food include proteins, carbohydrates, fats, minerals and vitamins.  These components are required in optimum quantities and serve a major role in vital activities.

WHO definition of Health

Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.

Health can be better regarded as :

l     The overall condition of an organism at a given time.

l     Soundness, especially of body or mind; freedom from disease or abnormality.

l     A condition of optimal well-being: concerned about the ecological health of the area.

l     Health is influenced by many factors – genetic, environmental, social, economical and psychological. The genetic constitution of an individual is unique.

Health and its importance

Good health has following advantages

l     Good health makes life pleasant.

l     Healthy being can perform effective work.

l     Good health makes a human being happy and cheerful.

Advantages of good health in business         

l     Every business has legal responsibilities to ensure the health and safety of employees and other people, and to protect the environment.

l     Poor health and safety leads to illness and accidents and significant costs for the business.

l     Effective health, safety and environmental practices pay for themselves. They also improve the  reputation with customers, the local community and the employees.

Psycho-social Health / Mental Health

Today the major concern among the health professionals is “stress” which can cause serious health problems. It can result in a major problem called depression, which is a serious condition and it should be tackled effectively.

Overcoming Depression

Warning signs of depression

l     The person feels sad, hopeless, or guilty most of the time

l     The person feels tired or lacks energy.

l     The person thinks of suicide or death.

l     Changes in sleeping and eating habits.

l     Sleep is either too much or too little.

l     Appetite gets changed. One gains or loses weight.

If one encompasses most of these symptoms for at least 2 weeks, he / she may be suffering from depression.

Depression usually is treated with counselling, medicine, or both. Medicines for depression are not addicting or habit forming. They work for people with severe depression and may be useful for people with mild to moderate depression.

Community Health

The science and practice of protecting and improving the health of a community, as by preventive medicine, health education, control of communicable diseases, application of sanitary measures, and monitoring of environmental hazards.

The mission of public health is to “fulfill society’s interest in assuring conditions in which people can be healthy.” The three core public health functions are:

l     The assessment and monitoring of the health of communities and populations at risk to identify health problems and priorities;

l     The formulation of public policies designed to solve identified local and national health problems and priorities;

l     To assure that all populations have access to appropriate and cost-effective care, including health promotion and disease prevention services, and evaluation of the effectiveness of that care.

Conditions essential for Good Health


Study of the materials that nourish an organism and of the manner in which the separate components are used for maintenance, repair, growth, and reproduction. Organisms such as plants that can thus manufacture complex organic compounds from simple inorganic nutrients are termed autotrophic. Organisms that must obtain “prefabricated” organic compounds from their environment are heterotrophic, and these include the fungi, some other plants, and animals. Heterotrophic plants may be saprophytic (obtaining nutrients from dead organisms) or parasitic (obtaining nutrients from living organisms while living on or in them). Heterotrophic animals may be parasites, herbivores (plant eaters), carnivores (meat eaters), or omnivores (obtaining nutrition from both plants and animals).

Importance of Good Nutrition

Good nutrition is reflected not only in the growth and function of the body but also in its appearance. The eyes, skin, hair, and teeth indicate whether body nourishment is good or poor. A poorly nourished child will fail to grow properly; a poorly nourished adult will have a decreased resistance to infection and disease. A diet deficient in proteins causes a disease called kwashiorkor in children; a diet deficient in both protein and calories results in marasmus, with lethargy, abdominal enlargement, and wasting—the classical malnutrition syndrome. Poor nutrition may result from excesses in the diet as well as deficiencies; excess of certain vitamins or minerals can produce potentially lethal disease states, and excess of carbohydrates or fat can result in obesity.

Personal and domestic hygiene.

For keeping good health, one should maintain personal hygiene such as taking bath regularly with soap and water, changing clothes regularly and washing hands properly before taking meals. One should also do brushing and flossing of the teeth and cleaning of tongue daily to check one’s foul breath. If we do not bathe everyday or change clothes every day when due to dirty conditions, the growth of microorganism takes place due to which our body as well as clothes begin to give foul smell.

Average height / weight of Boys
at different ages

Birth 3.3 50.5
3 months 6.0 61.1
6 months 7.8 67.8
9 months 9.2 72.3
1 year 10.2 76.1
2 years 12.3 85.6
3 years 14.6 94.9
4 years 16.7 102.9
5 years 18.7 109.9
6 years 20.7 116.1
7 years 22.9 121.7
8 years 25.3 127.0
9 years 28.1 132.2
10 years 31.4 137.5
11 years 32.2 140.0
12 years 37.0 147.0
13 years 40.9 153.0
14 years 47.0 160.0
15 years 52.6 166.0
16 years 58.0 171.0
17 years 62.7 175.0
18 years 65.0 177.0
Average height / weight of Girls
at different ages

Birth 3.2 49.9
3 months 5.4 60.2
6 months 7.2 66.6
9 months 8.6 71.1
1 year 9.5 75.0
2 years 11.8 84.5
3 years 14.1 93.9
4 years 16.0 101.6
5 years 17.7 108.4
6 years 19.5 114.6
7 years 21.8 120.6
8 years 24.8 126.4
9 years 28.5 132.2
10 years 32.5 138.3
11 years 33.7 142.0
12 years 38.7 148.0
13 years 44.0 150.0
14 years 48.0 155.0
15 years 51.5 161.0
16 years 53.0 162.0
17 years 54.0 163.0
18 years 54.4 164.0

Proper habits

Another important aspect of good health is to observe proper dietary habits, that is consumption of balanced diet and at fixed time. Good personal and domestic hygiene is very essential.

For keeping good health, we should avoid bad habits of chewing tobacco and smoking tobacco in the form of cigarette, beedi and hooka. Drinking alcohol in the form of wine, whisky, beer or country made liquor and taking narcotic drugs are also bad habits which should be avoided for keeping good health.


Food and its components

Food is a substance which when taken, digested and absorbed provides materials for activity (i.e., energy production), growth, repair (maintenance) and reproduction. Food is also needed by us for lactation (milk production by mothers), regulation of life processes and resistance to disease. The role the food plays shows that it essential for life.

For convenience three broad groups of food are discussed here, such as,

l     Energy giving: Carbohydrates and fats

l     Body building: Proteins

l     Protective: Minerals, vitamins.

Functions of food

Food is a kind of fuel for the living organisms. Human beings need food to live. The food performs the following functions in our body:

l     Food is essential to provide energy to the body.

l     Energy obtained from food is used to maintain body heat and to perform various life activities.

l     Food helps our body to grow.

l     Food provides materials for the repair of damaged cells and tissues of our body.

l     Food is essential for the manufacture of cellular products such as enzymes, histones, membranes, haemoglobin, antibodies, hormones, etc.

Components of Food

The components of food are certain organic substances and certain minerals. Nutrients of food are :


Carbohydrates (starches and sugars) provide a readily available energy source. Surplus carbohydrates are also converted by the body to glycogen and fat, the storage forms of calories for energy, and to some of the amino acids used in protein synthesis. Most health professionals recommend that carbohydrates comprise 50% to 60% of the dietary calories, of which most (80% of all carbohydrates eaten) should be complex carbohydrates, such as cereals and vegetables. Complex carbohydrates are preferred because the fast-acting simple carbohydrates, such as honey and sugar, are difficult for the body (especially the pancreas) to handle in large doses. Simple carbohydrates also lack the vitamins, minerals, proteins, and fibre that generally accompany foods rich in complex carbohydrates. Cereals, fruits, vegetables, legumes, and pasta are good sources of complex carbohydrates.

High-fibre (high-cellulose) vegetable foods are the healthiest choices for human nutrition, and intake of these foods is associated with lowered incidences of hypertension, cancer, arthritis, diabetes, etc. Examples are lettuce and broccoli. Examples of low-fibre are banana, tomato, squash and all cereals and grains (therefore bread and pasta), potatoes and rice.



Three common sugars share the same molecular formula: C6H12O6. Because of their six carbon atoms, each is a hexose.

They are:

l     glucose, “blood sugar”, the immediate source of energy for cellular respiration

l     galactose, a sugar in milk (and yogurt), and

l     fructose, a sugar found in honey.

Although all three share the same molecular formula (C6H12O6), the arrangement of atoms differs in each case. Substances such as these three, which have identical molecular formulas but different structural formulas, are known as structural isomers.

Glucose, galactose, and fructose are “single” sugars or monosaccharides. Two monosaccharides can be linked together to form a “double” sugar or disaccharide.


Three common disaccharides:

l     sucrose — common table sugar = glucose + fructose

l  lactose — major sugar in milk = glucose + galactose

l     maltose — product of starch digestion = glucose + glucose

Although the process of linking the two monomers is rather complex, the end result in each case is the loss of a hydrogen atom (H) from one of the monosaccharides and a hydroxyl group (OH) from the other. The resulting linkage between the sugars is called a glycosidic bond. The molecular formula of each of these disaccharides is

C12H22O11 = 2 C6H12O6 − H2O

All sugars are very soluble in water because of their many hydroxyl groups. Although not as concentrated a fuel as fats, sugars are the most important source of energy for many cells.


Proteins are among the most actively-studied molecules in biochemistry, and were discovered by Jöns Jakob Berzelius in 1838.

Protein in the diet provides amino acids for forming body proteins, including the structural proteins for building and repairing tissues, and the enzymes for carrying out the metabolic processes. In addition, protein may be used as a source of energy when the preferred fat and carbohydrate supply runs low. A body that is in the process of building itself (such as that of a growing child or an adult recovering from illness) will need a greater proportion of protein to weight than one that is fully grown and utilizes protein merely for repair of worn-out tissues. A protein (from the Greek protas meaning “of primary importance“) is a complex, high-molecular-mass, organic compound that consists of amino acids joined by peptide bonds. Proteins are essential to the structure and function of all living cells and viruses.

Proteins are a class of bio-macromolecules, alongside polysaccharides, lipids, and nucleic acids, that make up the primary constituents of biological organisms. Proteins are essentially polymers made up of a specific sequence of amino acids. In nutrition, proteins are broken down through digestion back into free amino acids for the organism, including those the organism may not be able to synthesize itself.

The average adult requires 1 gram of protein per kilogram of body weight per day; children may require two to three times this amount. Human proteins consist of up to 22 different amino acids, of which 9 (called essential amino acids) must be supplied by food protein; the other 13 are synthesized by human cells. Complete protein sources—those foods containing all 22 amino acids—include animal products such as meat, eggs, cheese, and milk. Incomplete protein sources, such as vegetables, beans, and grains, may be combined to create complete proteins.

Proteins are very large molecules made of amino acids, of which there are twenty. Eight of these amino acids are “essential,” meaning that they cannot be synthesized in the body even though they are necessary for life. Essential amino acids must be consumed from sources outside the body.

An ideal intake of protein is 0.8 grams per kilogram of body weight. Excess protein is defined as more than 1.6 grams per kilogram of body weight. For an average-size, seventy- kilogram man, this amounts to 70 x 1.6 = 112 grams. I understand that this is more than the officially recommended amount, however I believe the official recommendation to be low.


Fats (fats and oils) in the diet provide a concentrated source of energy; 1 gram of fat supplies about 9 calories as opposed to only 4 calories per gram of carbohydrates and protein. Fats in the body, in addition to acting as a source of stored energy, supply physical protection and insulation for tissues and form important portions of cell membrane structure. Fats also aid in the absorption of the fat-soluble vitamins (vitamins A, D, E, and K) from the intestine. Milk, butter, meat, and oils are important sources of fat.

Fat is a component in food. Some foods, including most fruits and vegetables, have almost no fat. Other foods have plenty of fat. They include nuts, oils, butter, and meats like beef.

The name – fat – may make it sound like something you shouldn’t eat. But fat is an important part of a healthy diet. And little kids, especially, need a certain amount of fat in their diets so the brain and nervous system develops correctly. That’s why toddlers need to drink whole milk, which has more fat, and older kids can drink low-fat or skim milk.

How much fat should you eat? Experts suggest kids who are 6 to 8 eat 48 to 60 grams per day. Older kids, between 9 and 12, should eat about 60 to 75 grams. That’s about 27% of a kid’s daily calories. Babies need more, but kids older than 2 and adults should get less than 30% of their daily calories from fat, nutrition experts say. You can figure out how many grams of fat are in a food by looking at the food label. Peanut butter, for instance, contains 16 grams of fat in 2 tablespoons.

Types of Fat

There are three major types:

Unsaturated fats

       These are found in plant foods and fish. These may be good for heart health. The best of the unsaturated fats are found in olive oil, peanut oil, canola oil, albacore tuna, and salmon.

Saturated fats

       These fats are found in meat and other animal products, such as butter, cheese, and all milk except skim. Saturated fats are also in palm and coconut oils, which are often used in commercial baked goods (the kind you buy at the store). Eating too much saturated fat can raise blood cholesterol levels and increase the risk of heart disease.

Trans fats

       These fats are found in margarine, especially the sticks. Trans fats are also found in certain foods that you buy at the store or in a restaurant, such as snack foods, baked goods, and fried foods. When you see “hydrogenated” or “partially hydrogenated” oils on an ingredient list, the food contains trans fats. Like saturated fats, eating too much can raise cholesterol and increase the risk of heart disease.

A fat molecule is composed of three fatty acid molecules, sixteen to eighteen carbons long, bound to each carbon of the three-carbon-long glycerol molecule. It is in the fatty acid chains where saturation, monounsaturation, polyunsaturation, and hydrogenation occur.

There are one, maybe two fatty acids which cannot be manufactured by the body and must be consumed from outside sources. Linoleic acid is definitely necessary for human nutrition, and it may be that linolenic acid also is necessary. Animal foods, except for fish and poultry, are low in linoleic acid, but they do meet human needs. Linoleic acid is abundant in vegetables. Linolenic acid is abundant in both vegetables and animal foods, and it is practically impossible to be in short supply of this nutrient unless starvation also is at your doorstep. The body knows how to manufacture the fatty substances it needs with the exceptions of linoleic and linolenic acids.


Vitamins are a group of substances essential for normal metabolism, growth and development, and regulation of cell function.

Vitamins work together with enzymes, co-factors (substances that assist enzymes), and other substances necessary for healthy life.

A vitamin is an organic molecule required by a living organism in minute amounts for proper health. An organism deprived of all sources of a particular vitamin will eventually suffer from disease symptoms specific to that vitamin.

Vitamins can be classified as either water soluble, which means they dissolve easily in water, or fat soluble, which means they are absorbed through the intestinal tract with the help of lipids.

Water Soluble Vitamins

Fat Soluble Vitamins
l     Thiamine (B1)

l     Riboflavin (B2)

l     Niacin (B3)

l     Pantothenic Acid (B5)

l     Pyridoxal, Pyridoxamine, Pyridoxine (B6)

l     Biotin

l     Cobalamine (B12)

l     Folic Acid

l     Ascorbic Acid (vitamin C)

l     Vitamin A

l     Vitamin D

l     Vitamin E

l     Vitamin K


In general, an organism must obtain vitamins or their metabolic precursors from outside the body, most often from the organism’s diet. Examples of vitamins that the human body can derive from precursors include vitamin A, which can be produced from beta carotene; niacin from the amino acid tryptophan; and vitamin D through exposure of skin to ultraviolet light.

The word vitamine was coined by the Polish biochemist Casimir Funk in 1912. Vita in Latin is life and the -amine suffix is for amine; at the time it was thought that all vitamins were amines

Each vitamin has specific functions. If levels of a particular vitamin are inadequate, a deficiency disease results.

  • Vitamin A helps in the formation and maintenance of healthy teeth, skeletal and soft tissue, mucous membranes, and skin. It is also known as retinol because it generates the pigments that are necessary for the working of the retina. It promotes good vision, especially in dim light. Vitamin A may also be required for reproduction and breast-feeding. Beta-carotene is a precursor to vitamin A that has antioxidant properties, helping the body deal with unstable chemicals called free radicals.
  • Thiamine (B1) helps the body cells convert carbohydrates into energy. It is also essential for the functioning of the heart and for healthy nerve cells, including those in the brain.
  • Riboflavin (B2) works with the other B vitamins and is important for body growth and red blood cell production. Similar to thiamine, it helps in releasing energy from carbohydrates.
  • Niacin is a B vitamin that helps maintain healthy skin and nerves. It is also important for the conversion of food to energy and may have cholesterol-lowering effects.
  • Vitamin B6 is also known as pyridoxine. The more protein a person eats, the more vitamin B-6 is required to help the body use the protein. It aids in the formation of red blood cells and in the maintenance of normal brain function. It also assists in the synthesizing of antibodies in the immune system.
  • Vitamin B12, like the other B vitamins, is important for metabolism. It, too, helps in the formation of red blood cells and in the maintenance of the central nervous system.
  • Pantothenic acid is essential for the metabolism of food. It is also essential in the synthesis of hormones and cholesterol.
  • Biotin is essential for the metabolism of proteins and carbohydrates, and in the synthesis of hormones and cholesterol. Cholesterol is needed for the functioning of cell membranes, particularly in the brain.
  • Folate (folic acid) works with vitamin B-12 in the production of red blood cells. It is necessary for the synthesis of DNA, which controls heredity as well as tissue growth and cell function. Any woman who may become pregnant should be sure to consume enough folate — low levels of this substance are associated with devastating birth defects such as spina bifida. Many foods are now fortified with folic acid to help reduce the level of such birth defects.
  • Vitamin C also called ascorbic acid, promotes healthy teeth and gums, helps in the absorption of iron, and helps maintain normal connective tissue. It also promotes wound healing and is an antioxidant.
  • Vitamin D is also known as the “sunshine vitamin,” since it is manufactured by the body after being exposed to sunshine. Ten to 15 minutes of sunshine three times per week is adequate to produce the body’s requirement of vitamin D. This vitamin promotes the body’s absorption of calcium, which is essential for the normal development and maintenance of healthy teeth and bones. It also helps maintain adequate blood levels of calcium and phosphorus, which are minerals necessary for many functions.
  • Vitamin E is also known as tocopherol and is an antioxidant. It is also important in the formation of red blood cells and the use of vitamin K.
  • Vitamin K is known as the clotting vitamin, because without it blood would not coagulate. Some studies indicate that it helps in maintaining strong bones in the elderly.


Food Sources

There are 13 vitamins essential for bodily functions: Vitamins A, C, D, E, K, and the B vitamins (thiamine, riboflavin, niacin, pantothenic acid, biotin, vitamin B-6, vitamin B-12, and folate). They all can be obtained from food, and vitamin D and vitamin K can be synthesized by the body.


Adequate Intake (AI) for Potassium
Life Stage Age Males (mg/day) Females (mg/day)
Infants 0-6 months 400 400
Infants 7-12 months 700 700
Children 1-3 years 3000 3000
Children 4-8 years 3800 3800
Children 9-13 years 4500 4500
Adolescents 14-18 years 4700 4700
Adults 19 years and older 4700 4700
Pregnancy 14-50 years 4700
Breastfeeding 14-50 years 5100


Calcium is the most common mineral in the human body. About 99% of the calcium in the body is found in bones and teeth, while the other 1% is found in the blood and soft tissue. Calcium levels in the blood and fluid surrounding the cells (extracellular fluid) must be maintained within a very narrow concentration range for normal physiological functioning. The physiological functions of calcium are so vital to survival that the body will demineralize bone to maintain normal blood calcium levels when calcium intake is inadequate. Thus, adequate dietary calcium is a critical factor in maintaining a healthy skeleton.


Calcium is a major structural element in bones and teeth. The mineral component of bone consists mainly of hydroxyapatite [Ca10(PO4)6(OH)2] crystals, which contain large amounts of calcium and phosphate. Bone is a dynamic tissue that is remodeled throughout life. Bone cells called osteoclasts begin the process of remodeling by dissolving or resorbing bone. Bone-forming cells called osteoblasts then synthesize new bone to replace the bone that was resorbed. During normal growth, bone formation exceeds bone resorption. Osteoporosis may result when bone resorption exceeds formation.


Increased sodium intake results in increased loss of calcium in the urine, possibly due to competition between sodium and calcium for reabsorption in the kidney or by an effect of sodium on parathyroid hormone (PTH) secretion. Each 2.3-gram increment of sodium (6 grams of salt; NaCl) excreted by the kidney has been found to draw about 24-40 milligrams (mg) of calcium into the urine. Because urinary losses account for about half of the difference in calcium retention among individuals, dietary sodium has a large potential to influence bone loss. In adult women, each extra gram of sodium consumed per day is projected to produce an additional rate of bone loss of 1% per year if all of the calcium loss comes from the skeleton.


Phosphorus, which is typically found in protein-rich foods, tends to decrease the excretion of calcium in the urine. However, phosphorus-rich foods also tend to increase the calcium content of digestive secretions, resulting in increased calcium loss in the faces. Thus, phosphorus does not offset the net loss of calcium associated with increased protein intake. Increasing intakes of phosphates from soft drinks and food additives have caused concern among some researchers regarding the implications for bone health. Diets high in phosphorus and low in calcium have been found to increase parathyroid hormone (PTH) secretion, as have diets low in calcium. While the effect of high phosphorus intake on calcium balance and bone health are presently unclear, the substitution of large quantities of soft drinks for milk or other sources of dietary calcium is cause for concern with respect to bone health in adolescents and adults.

Adequate Intake (AI) for Calcium
Life Stage  Age Males (mg/day) Females (mg/day)
Infants 0-6 months 210 210
Infants 7-12 months 270 270
Children 1-3 years 500 500
Children 4-8 years 800 800
Children 9-13 years 1,300 1,300
Adolescents 14-18 years 1,300 1,300
Adults 19-50 years 1,000 1,000
Adults 51 years and older 1,200 1,200
Pregnancy 18 years and younger 1,300
Pregnancy 19 years and older 1,000
Breastfeeding 18 years and younger 1,300
Breastfeeding 19 years and older 1,000


Iron has the longest and best described history among all the micronutrients. It is a key element in the metabolism of almost all living organisms. In humans, iron is an essential component of hundreds of proteins and enzymes.



Oxygen transport and storage

Heme is an iron-containing compound found in a number of biologically important molecules. Hemoglobin and myoglobin are heme-containing proteins that are involved in the transport and storage of oxygen. Hemoglobin is the primary protein found in red blood cells and represents about two thirds of the body’s iron. The vital role of hemoglobin in transporting oxygen from the lungs to the rest of the body is derived from its unique ability to acquire oxygen rapidly during the short time it spends in contact with the lungs and to release oxygen as needed during its circulation through the tissues. Myoglobin functions in the transport and short-term storage of oxygen in muscle cells, helping to match the supply of oxygen to the demand of working muscles.

Recommended Dietary Allowance (RDA) for Iron
Life Stage Age Males (mg/day) Females (mg/day)
Infants 0-6 months 0.27 (AI) 0.27 (AI)
Infants 7-12 months 11 11
Children 1-3 years 7 7
Children 4-8 years 10 10
Children 9-13 years 8 8
Adolescents 14-18 years 11 15
Adults 19-50 years 8 18
Adults 51 years and older 8 8
Pregnancy all ages 27
Breastfeeding 18 years and younger 10
Breastfeeding 19 years and older 9


Food Sources

The amount of iron in food (or supplements) that is absorbed and used by the body is influenced by the iron nutritional status of the individual and whether or not the iron is in the form of heme. Because it is absorbed by a different mechanism than nonheme iron, heme iron is more readily absorbed and its absorption is less affected by other dietary factors. Individuals who are anemic or iron deficient absorb a larger percentage of the iron they consume (especially nonheme iron) than individuals who are not anemic and have sufficient iron stores.

Heme iron

Heme iron comes mainly from hemoglobin and myoglobin in meat, poultry, and fish. Although heme iron accounts for only 10-15% of the iron found in the diet, it may provide up to one third of total absorbed dietary iron. The absorption of heme iron is less influenced by other dietary factors than that of nonheme iron.


Food Serving Iron content (mg)
Beef 3 ounces, cooked 2.31
Chicken, dark meat 3 ounces, cooked 1.13
Oysters 6 medium 5.04
Tuna, light 3 ounces, canned 1.30
Black-strap molasses 1 tablespoon 3.50
Raisins, seedless 1 small box (1.5 ounces) 0.89
Potato, with skin 1 medium potato, baked 2.75
Kidney beans 1/2 cup, cooked 2.60
Lentils 1/2 cup, cooked 3.30
Cashew nuts 1 ounce 1.70


Iodine, a non-metallic trace element, is required by humans for the synthesis of thyroid hormones. Iodine deficiency is an important health problem throughout much of the world. Most of the Earth’s iodine is found in its oceans. In general, the older an exposed soil surface, the more likely the iodine has been leached away by erosion. Mountainous regions, such as the Himalayas, the Andes, and the Alps, and flooded river valleys, such as the Ganges, are among the most severely iodine deficient areas in the world.


Iodine is an essential component of the thyroid hormones, triiodothyronine (T3) and thyroxine (T4) and is therefore, essential for normal thyroid function. To meet the body’s demand for thyroid hormones, the thyroid gland traps iodine from the blood and converts it into thyroid hormones that are stored and released into the circulation when needed. In target tissues, such as the liver and the brain,


Recommended Dietary Allowance (RDA) for Iodine
Life Stage  Age  Males (mcg/day)  Females (mcg/day) 
Infants 0-6 months 110 (AI) 110 (AI)
Infants 7-12 months  130 (AI)  130 (AI)
Children 1-3 years 90 90
Children  4-8 years 90 90
Children 9-13 years 120 120
Adolescents 14-18 years 150 150
Adults 19 years and older 150 150
Pregnancy all ages 220
Breastfeeding all ages 290

Food sources

The iodine content of most foods depends on the iodine content of the soil in which it was raised. Seafood is rich in iodine because marine animals can concentrate the iodine from seawater. Certain types of seaweed (e.g. wakame) are also very rich in iodine. Processed foods may contain slightly higher levels of iodine due to the addition of iodized salt or food additives, such as calcium iodate and potassium iodate.

Food Serving Iodine (mcg)
Salt (iodized) 1 gram 77
Cod 3 ounces 99
Shrimp 3 ounces 35
Fish sticks 2 fish sticks 35
Tuna, canned in oil 3 ounces (1/2 can) 17
Milk (cow’s) 1 cup (8 fluid ounces) 56
Egg, boiled 1 large 29
Navy beans, cooked 1/2 cup 35
Potato with peel, baked 1 medium 63
Turkey breast, baked 3 ounces 34
Seaweed 1 ounce, dried Variable; may be greater than 18,000 mcg (18 mg)



Fibre in Nutrition

Constipation has become a common complaint, and the incidence of gastrointestinal disorders of many different varieties — for example, appendicitis, gallbladder disease, irritable bowel syndrome, hypoglycemia and intestinal cancers — has shot up to unprecedented levels.

The processed food industry has made a lot of money in this transformation of food and so have physicians and surgeons! The losers have been the millions of people who trust the food industry to deliver healthy products for their consumption and who trust their doctors to know how to advise them to prevent illness.

The advantage of fibre in the diet is that it moves food through the digestive system quickly, it protects the body from absorbing toxins, which may be associated with the  food (pesticides, for example), it modulates the absorption of simple carbohydrates, and it keeps the walls of the intestine clean by removing toxins which are believed to cause cancer. Fibre also modulates the amount of salt we consume, containing just the right amount, and thus works to prevent hypertension and the results of hypertension: kidney and heart disease.

Food Adulteration

Food adulteration, act of intentionally debasing or deteriorating the quality of food offered for sale either by the mixture or substitution of inferior substances or by the removal of some valuable ingredient. Preparation and processing of food products may modify their nutritional value and use of food additives may introduce direct or indirect toxicity, but the real hazards to health are caused by food adulteration. In order to curb the menace of food adulteration, Government of India introduced the prevention of Food Adulteration Act, 1954 with prevention of Food Adulteration rules 1955. The object of this food legislation is to prevent adulteration and misbranding of foods as defined therein and punish responsible one because it is crime against humanity. The social evil of fraudulently selling adulterated food stuffs not only affects the health of the citizens but tends to demoralize the whole nation and grievously obstructs its moral and economic progress. The provisions of the act are directed for the purpose of securing economic progress.

What is Adulterated Food?

An article of food shall be deemed to be adulterated

l     If the article sold by a vendor is not of the nature, substance or quality demanded by the purchaser or which it purports to be.

l     If the article contains any substance affecting its quality or of it is so processed as to injuriously affect its nature, substance or quality.

l     If any inferior or cheaper substance has been substituted wholly or partly for the article, or any constituent of the article has been wholly or partly abstracted from it, so as to affecting its quality or of it is so processed as to injuriously affect its nature, substance or quality.

l     If the article had been prepared, packed or kept under insanitary conditions whereby it has become contaminated or injurious to heath.

l     If the article consists wholly or in part of any filthy, putrid, disgusting, rotten, decomposed or diseased animal or vegetable substance or being insect-infested, or is otherwise unfit for human consumption.

l     If the article is obtained from a diseased animal.

l     If the article contains any poisonous or other ingredient which is injurious to health.

l     If the container of the article is composed of any poisonous or deleterious substance which renders its contents injurious to health.

l     If the article contains any prohibited colouring matter or preservative, or any permitted colouring matter or preservative in excess of the prescribed limits.

  • If the quality or purity of the article falls below the prescribed standard, or its constituents are present in proportions other standard, or its constituents are present in proportions other than those prescribed, whether or not rendering it injurious to health.

Prevention of Food Adulteration

Prevention of Food Adulteration Act 1954 – Aims at the abatement of adulteration in food articles of human consumption commonly used by the people so as to enable the people to have access to wholesome and unadulterated food.

l     In the Municipalities having a Health Officer, the Municipal Health Officer concerned and in the Municipalities without having a Health Officer, Municipal Commissioner concerned acts as Local Health Authority. In the Corporations the Health Officer concerned acts as Local Health Authority.

l     In the rural areas Medical Officers of the Primary Health Centres are functioning as Local Health Authorities.

l     The food Inspectors function under the control and guidelines of the Local Health Authority for the purpose of enforcement of the Act.

l     Lifting of food-samples have been fixed only for local bodies including all Corporations, Municipalities contonments and certain Special Panchayats, Town Panchayat and Panchayat Unions.

l     If the food sample analysed in the food lab is reported as adulterated / misbranded by the government Analyst / Public Analyst the Food Inspectors launch prosecution after getting permission from State Local Health Authority.

Tests for Detection of Food Adulterants

l     Metanil Yellow in Dal : Shake five grams of dal with five ml of water. Add a few drops of hydrochloric acid. A pink colour indicates the presence of metanil yellow.

l     Argemone Oil in Edible Oil : Add concentrated nitric acid to the sample and shake carefully. Observe the colour of the acid layer. A red to reddish brown colour indicates the presence of argemone oil.

l     Vanaspati in Ghee : Melt one teaspoonful of ghee or butter sample in a test tube. Add an equal amount of concentrated hydrochloric acid and a pinch of common sugar. Shake well for about one minute and allow the tube to stand for five minute and allow the tube to stand for five minutes. If you observe a crimson colour appearing in the lower layer, it shows the presence of vanaspati in ghee or butter.

Food Material Adulterant
Cereals such as wheat, rice Mud, grit, soapstone
Dal Kesari dal, metanil yellow (a dye)
Haldi powder Lead chromate
Dhania powder Powdered cowdung or horsedung, starch
Black pepper Dried papaya seeds
Chilli powder Saw dust, brick powder
Mustard seeds Argemone seeds
Edible oils Cheaper oils such as mineral and Argemone oils
Milk Extraction of fat, addition of starch
Honey Jaggery, Sugar



Very Short Answer Questions


  1. Give the definition of health given by WHO?
  2. Name protein present in milk?
  3. What is meant by quarantine?
  4. Name a protein energy malnutrition syndrome.
  5. What is difference between a disease and syndrome.

Short Answer Questions

  1. Write any four function of food?
  2. Name any two disaccharides.
  3. What is a glycosidic bond?
  4. What is an amino acid?
  5. What are trans fats?

Long Answer Questions

  1. Name the sources and deficiency diseases caused by the water soluble vitamins.
  2. What is the role calcium, phosphorus and vitamin D in maintenance healthy bones and teeth?
  3. Explain the deficiency disease caused due to the less intake of iodine in the diet.
  4. What are the beneficial effects of fibre in the diet.
  5. Write down the sources and deficiency diseases caused by Vitamin A & D.


  1. You are aware of Polio Eradication Programme in your city. Children are vaccinated because –

(a)        vaccination kills polio causing micro-organisms

(b)        Prevents the entry of polio causing micro-organisms

(c)        It creates immunity in the body.

(d)        all the above.

  1. ‘BCG’ vaccine is given to infants for protection against –

(a) Diarrhoea         (b) Cholera        (c) Pneumonia               (d) Tuberculosis

  1. Which one is not sexually transmitted disease?

(a) AIDS          (b) Gonorrhoea         (c) Syphilis        (d) Diabetes.

  1. Which one of the following causes kala-azar?

(a) Ascaris (b) Trypanosome (c) Leishmania (d) Bacteria

  1. Name the target organs for the following disease-

(a) Hepatitis targets ______________

(b) Fits or unconsciousness targets __________________

(c) Pneumonia targets _________________

(d) Fungal disease targets ______________

  1. How are diseases diagnosed by physician?
  2. Who discovered ‘vaccine’ for the first time? Name two diseases which can be prevented by using
  3. Name the approaches generally adopted to treat infectious diseases.
  4. Explain giving reasons –

(a) Balanced diet is necessary for maintaining health body.

(b) Health of an organism depends upon the surrounding environmental conditions.

  1. What is immunization, immune system, immunity?
  2. Name the agents and the diseases caused by them?
  3. What are the different aspects of maintaining good health?