Food is anything intended to supply energy or nourishment to the body. It is any substance consumed by living organisms to provide nutritional support.It is usually of plant or animal origin, and it contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals.
The foods and beverages you eat and drink supply your body with the basic nutrients you need to support your health on a daily basis. Some of these food components must undergo digestion before you can benefit from them, although not all food component undergo digestion.
All together these nutrients (water, protein, fat, carbohydrate, minerals and vitamins) promote your health when you consume them regularly through your diet. Remember humans are omnivorous animals that can consume both plant and animal products.
However, food is needed to repair and replace body tissues, build healthy body, supply energy for the body,maintain body temperature and build new cells, maintain life, or stimulate growth.
Another way to categorise food is by the type of nutrient it contains and its role in the body. A nutrient is a compound your body needs for energy, growth, basic physiological processes and your overall health. Also nutrient is a source of nourishment such as food that can be metabolised by an organism to give energy and build tissue.
Nutrient is further divided into three categories which are plant Nutrient, animal Nutrient and plant and animal nutrient mixed together. The first class of the nutrient is ‘Rich’, the second class of the nutrient is poor, while the third class is regarded as nutrient barren and they all serve different purposes in the body.
FIRST CLASS, NUTRIENT-RICH
These are plant foods that are rich in virtually all of the nutrients your body needs to function, stay healthy and perform well. They also have fiber and phytochemicals, and they do not contain substances your body does not need.
It is recommended that you maintain a diet that is made up of at least 90% or More Plant-Based, Nutrient-Rich foods, meals, and menus for the best all-around results. Examples of these super-foods include:
- Vegetables
- Fruits
- Legumes (beans)
- Raw Nuts and Seeds
- Whole, unrefined grains
SECOND-CLASS, NUTRIENT-POOR
These are animal-based foods that are rich in some nutrients but are missing whole categories of others. They also contain substances like cholesterol and saturated fat that the body does not need from dietary sources.
It is recommended that you maintain a diet that includes no more than 10% animal foods if you decide to eat them at all. Examples of these foods include:
- Fish
- Low Fat Dairy
- Full-fat Dairy
- Chicken and Beef
- Eggs
THIRD-CLASS, NUTRIENT-BARREN
These are foodstuffs of both plant and animal origin that have been refined and stripped of their nutrients. While some are added back in for nutritional and marketing purposes, most of the ingredients are highly concentrated pleasure-stimulating substances that addict you, while making you fat and sick.
It is recommended that you eat these foodstuffs rarely or avoid them all together. Examples of these foods include:
- Refined grains
- Refined Oil and Sweets
Basic Form of Nutrients
Nutrients can be divided into 2 categories: macro-nutrients, and micro-nutrients. Macro-nutrients are those nutrients that the body needs in large amounts. These provide the body with energy (calories).
Micronutrients are those nutrients that the body needs in smaller amounts. Click on the links below to discover the functions, recommended dietary intake, and food sources of the different nutrients our bodies need.
MACRO-NUTRIENTS
- Carbohydrates
- Proteins
- Fats
MICRO-NUTRIENTS
Water Soluble Vitamins
- Vitamin B1
- Vitamin B2
- Vitamin B6
- Vitamin B12
- Vitamin C
- Folic Acid
Fat Soluble Vitamins
- Vitamin A
- Vitamin D
- Vitamin E
- Vitamin K
Minerals
- Calcium
- Potassium
- Sodium
- Iron
- Zinc
Water
- Water
Classes Of Foods
Chapter 5. Food Nutrition and Healthy Eating. Carbohydrates. Fats. Proteins. Vitamins. Minerals. Water. Six Classes of Nutrients.
Nutrients are chemicals found in foods that are essential to human growth and function. There are basic Six classes of food nutrients which are Carbohydrates, Proteins, fact and oil, Vitamins, Minerals and Water. All the six components have certain functions that target different body part and together they ensure the state of the overall health.
1. Carbohydrates
Carbohydrates (literally hydrates of carbon) are chemical compounds which act as the primary biological means of storing or consuming energy; This means carbohydrates is the major source of energy which we need for human functioning and physical activity.
Similar to fat, digestible carbohydrate in your diet provides you with energy, although in a more readily available form than that in fat. This nutrient also acts as a structural molecule for example, part of your liver and muscles contain a storage form of starch called glycogen.
carbohydrates are known as polysaccharides.The simplest carbohydrates are monosaccharides, which are small straight-chain aldehydes and ketones with many hydroxyl groups added, usually one on each carbon except the functional group.
Other carbohydrates are composed of monosaccharide units, and break down under hydrolysis. These may be classified as disaccharides, oligosaccharides, or polysaccharides, depending on whether they have two, several, or many monosaccharide units.
Carbohydrates are divided into two categories: Simple carbohydrates metabolise quickly, offering your body fast but short-lived energy. Complex carbohydrates digest slowly and provide a steady supply of energy. White rice and pasta are examples of simple carbohydrates. Whole-grain bread, steel-cut oats and lentils are complex carbohydrates.
Indigestible carbohydrate, known as dietary fiber, doesn’t contribute fuel or structure to your cells, but it can help improve your digestive health by affecting how quickly food moves through your gut.
Sources Of Carbohydrates
Carbohydrates are found in a wide array of both healthy and unhealthy foods—bread, beans, milk, popcorn, potatoes, cookies, spaghetti, soft drinks, corn, and cherry pie. They also come in a variety of forms.
There are three main sources of carbohydrate which include
(i) Starches: Starches are present in plenty of cereals, roots, tubes and also in plant stems. Cereals (wheat, rice) account for most of the dietary carbohydrate.
(ii) Sugar: Sugar can be found in fruits, honey and things that produce sugar. Glucose is an essential element of sugar. This is very much needed for small children, especially during the period of teething and their growth stage. Lactose and jams, other fruits and honey also provide sugar. The consumption of sugar increases as the economic status of the people rises.
(iii) Cellulose: Cellulose is the fibrous substance of fruits and vegetables. It is hard to digest and has no nutritive value. Its main function is to serve as roughage and facilitate bowel movements.
2. Proteins
The protein in your diet serves as a source of amino acids that create the specific structural and functional proteins your body needs. For example, proteins make up your muscle tissue, support your immune health, transport molecules in and out of your cells and provide the basis for hormones and enzymes.
Your food proteins are too large for your gut to absorb, so your digestive system breaks them down into single amino acids that can travel to the cells and tissues throughout your body where they are needed. Also, proteins support the growth, repair and maintenance of tissues.
Protein plays an essential role in repairing damaged tissue and building new tissue throughout the body. It also acts as a tertiary source of energy. You don’t need a protein shake to benefit from this food class. Many foods like dairy products, meat, beans, poultry, nuts and fish are naturally rich in protein.
Imperatively, protein is made up of carbon, hydrogen, oxygen and nitrogen and food rich in protein are fish, milk, meat, beans, albumen and nuts. Protein is required for building new cells. Moreover, protein is also needed for growth and to replace damaged tissues.
Functions of Proteins
Proteins are needed in the body for the following purposes
(i) For growth and development,
(ii) For repair and maintenance and
(iii) For synthesis of certain substances like the anti I bodies, enzymes and hormones.
Proteins are used as a source of energy. Proteins play a major role in the maintenance of goo nutritional status. At present, protein malnutrition is the greatest threat to health especially among children.
Sources Of Proteins
Proteins are found in both animal and vegetable foods and are spoken of as animal and vegetable proteins. The animal sources of protein are milk, eggs, meet, fish, liver, etc. while vegetable proteins are found chiefly in the pulses such as peas and beans.
Modern nutritional scientists prefer to use the term ‘protein rich foods in place of first or second class proteins. The protein rich foods of animal sources and plant sources are essential in human nutrition.
3. Fats And Oils
In biochemistry, fat is a generic term for a class of lipids. Fats are produced by organic processes in animals and plants. All fats are insoluble in water and have a density significantly below that of water (i.e. they float on water.) Fats that are liquid at room temperature are often referred to as oil.
However, the fats you eat supply you with a very concentrated source of energy that you can store in your adipose tissue for later use. Dietary fat, which you must digest prior to use, also plays a role in maintaining healthy cell membranes, and it functions in the synthesis of steroid hormones, such as estrogen and testosterone.
Fats are divided into categories based on their physical characteristics. Saturated fats are solid at room temperature and include foods such as butter, cheese and the white marbling in steak.
Unsaturated fats are liquid at room temperature and include foods such as olive and walnut oil. Replace saturated fats with unsaturated fats as much as possible for good health.
Although you need some fat in your diet each day, too much can cause you to take in excess calories and increase your risk of obesity. In addition, consuming a high level of saturated fats those that are solid at room temperature can predispose you to heart disease.
Functions Of Fats And Oils
(i) Fats are concentrated and palatable sources of food energy. One gram of fat yields about 9 calories of energy.
(ii) Fats carry fat-soluble vitamins— A.D.E. and K
(iii) Fats provide ‘essential fatty acids’. These are required by the body for growth and maintenance of the integrity of the skin.
(iv) Fats provide support for many organs in the body such as heart, kidney and intestine. However, Fat beneath the skin is insulation against cold.
Sources Of Fats And Oils
Dietary fats are derived from two main sources:
(i) Animal Sources
They are ghee, butter and fish oils. Animal fats have more saturated fatty acids than vegetables fats. They also contain vitamins A and D which are lacking in vegetable fats.
(ii) Vegetable sources
They include various vegetable oils such as groundnut, mustard and coconut oil. Vanaspathi which is a popular cocking medium in some part of the world Also India manufactured from groundnut oil and cottonseed oil, which are converted into solid fat.
Fats such as butter, ghee and vegetable oils are known as ‘visible’ fats because it is easy to estimate their intake. But fats present in such foods as milk, eggs, meat and nuts which also find a place in the human diet are very difficult to estimate and are therefore called ‘invisible’ fats.
4. Water
It may seem strange to include water as a food class, but water acts as an essential solvent for chemicals in the cells, rids the body of waste and helps regulate body temperature. Drinking water is important, but you also get lots of water from fresh food.
Because so much of your body consists of water, and you use it in so many reactions within your cells, water is more essential than any other nutrient. In addition, your body can lose water quite easily, from urination, perspiration and evaporation, and you therefore need to replace it on a continual basis.
Losing only 1 to 2 percent of your body’s water weight can result in weakness and fatigue, while 10 percent loss of your body’s water can lead to life-threatening heat stroke. Most adults need to consume between 2 and 3 litres of water each day, although you may need more in hot weather or if you are physically active.
Water is also needed to control body temperature, remove excretory products from body and lubricate your body. Furthermore, water also acts as a medium for biochemical reactions in the body.
Your body uses water in all its cells, organs, and tissues to help regulate its temperature and maintain other bodily functions. Because your body loses water through breathing, sweating, and digestion, it’s important to re-hydrate by drinking fluids and eating foods that contain water.
The amount of water you need depends on a variety of factors, including the climate you live in, how physically active you are, and whether you’re experiencing an illness or have any other health problems
Functions Of water
- Water protects your tissues, spinal cords and joints
- Water helps your body remove waste
- Water aids digestion
- Water prevent your body from been dehydrated
- Water also critical because it assists in the regulations of nerve impulses
- regulates body temperature
- Protect vital organs
- Prevent constipation
- Delivers nutrients
Sources of water
Aside from the obvious glass of water, you can also get this critical nutrient from food. Vegetables like lettuce, cucumber, tomato, sugar snap peas, and celery have a very high water content, which also makes them very low in calories but still high in nutrient value. Fruits like oranges, pineapples, strawberries, and others, also have high water content. Broth based soups, milk, and juices do contain a high percentage of water.
5. Minerals
Minerals are inorganic micro-nutrients, which means they do not contain carbon. There are 16 minerals that your body needs to function, including calcium and iron. Iron is part of red blood cells and ensures that oxygen is delivered to all the cells in your body. Calcium keeps your bones and teeth strong and healthy.
Electrolyte minerals, including sodium and potassium, help maintain fluid balance in your body. Minerals are found in an array of foods including dairy, meat, fruits and vegetables.
Minerals assist in the regulation of many body functions, some of which involve regulating fluids and producing energy, healthy bones and blood. This nutrient also helps rid our body of harmful products of metabolism.
Minerals are also required in small quantities. Examples of minerals are calcium, sodium, iron, iodine, phosphorus and potassium. Minerals help to protect and prevent our body from diseases such as rickets and goiter.
Calcium in Mineral provides structure to your bones, potassium helps regulate blood pressure, iron transports oxygen through your blood and zinc helps keep your immune system healthy. However, minerals need to be digested before your body can absorb them. These small molecules serve a wide variety of purposes in your cells and tissues.
Functions Of Minerals
1. They Constitutes various body tissues e.g. iron, phosphorus.
2. They maintain electrolyte balance in body fluids e.g. sodium, potassium and chloride.
3. They maintain tone and functions of muscles e.g. sodium and calcium.
4. They stimulate digestive secretions.
5. They are necessary for growth.
Sources Of Minerals
1. Milk and milk products like cheese, curd and butter milk. They arc the best natural sources of calcium.
2. Green leafy vegetables like spinach.
3. Millet’s like ragi.
6. Vitamins
Vitamins are essential nutrient because they build and maintain healthy bones and muscle tissues. They also support our immune system while maintaining the blood to ensure healthy vision. vitamins are micro-nutrients because they are needed in small quantity or amount to sustain our normal health and body functions.
There are six types of vitamins which are vitamins A,B,C,D,E and K. Vitamins B and Care soluble in water while vitamins A,D,E and K are soluble in fat.Vitamin is vital to protect our body from diseases and maintains the health of our body
Vitamins are also involved in multiple processes. Vitamin A helps fight inflammation and vitamin D improves calcium absorption, while many of the B vitamins assist in deriving energy from the foods you eat each day.
However, vitamins need to be digested before your body can absorb them. These small molecules serve a wide variety of purposes in your cells and tissues. Fruits and vegetables are particularly rich sources of vitamins.
Functions Of Vitamins
Vitamin A: Vitamin A is responsible for promoting vision, bone growth, tooth development, immunity, cell reproduction, formation of hormones, and maintenance of healthy skin, hair and mucous membranes.
The retinol form of vitamin A is found in animal products such as liver, milk and eggs, while beta-carotene is abundant in plant foods, including carrots, sweet potatoes, mangos, spinach, pumpkin and apricots.
Vitamins B: The B complex vitamins consist of thiamine, or B1; riboflavin, or B2; niacin, or B3; pantothenic acid, or B5; pyridoxine or B6; biotin, or B7; folate, or B9; and cobalamin, or B12. Each of these B vitamins serves different functions, including energy production from food, growth, red blood cell production, the formation of hormones, antibody creation, central nervous system function and metabolic processes. Nearly all foods contain B vitamins, especially animal products.
Vitamin C: Vitamin C plays a significant role as an antioxidant, protecting the body from tissue damage by oxidation. Free radicals, which are byproducts of normal metabolism and environmental factors, cause cellular damage, leading to disease and illness. Antioxidants stabilize free radicals, preventing damage to the body.
Vitamin C is also required for healthy skin, bones, cartilage, teeth, gums, blood vessels, production of collagen and iron absorption. Red berries, kiwi, bell peppers, tomatoes, broccoli, spinach, guava and citrus fruits are excellent sources of vitamin C.
Vitamin D: Vitamin D is known as the sunshine vitamin because it is produced by the body after exposure to sunshine. Vitamin D is found in dairy products, fish, sunflower seeds and egg yolks; however, very little vitamin D is needed from dietary sources if sufficient vitamin D is absorbed from sunlight. Vitamin D not only strengthens bones, but also is necessary for the absorption and maintenance of calcium and magnesium in the body.
Vitamin E: Natural antioxidant, vitamin E protects body tissues from oxidative damage. It is also important in the health of red blood cells and the use of vitamin K. It aids in healing, prevention of scarring, and it soothes broken or stressed skin tissue. Green leafy vegetables, wheat germ, whole grains, nuts and vegetable oils are good sources of vitamin E.
Vitamin K: Abundant in milk, liver, wheat bran, nuts and a variety of fruits and vegetables, vitamin K regulates blood calcium levels and activates proteins involved in bone health. The primary function of vitamin K is its crucial role in the blood clotting process. Vitamin K aids blood clot formation, stopping bleeding when necessary.
Classification of Food
If you want to eat a healthy diet, you’ll need to understand the five food groups. The five food groups are vegetables, fruits, grains, dairy and protein. A healthy, balanced diet will include food from each group.
Grains and Proteins
Grains are classified as any food made from wheat, rice, oats, cornmeal, barley or other cereal grains. The The United State Department of Agriculture (USDA) suggested that eating at least half of your grain intake should come from whole grains, such as in whole wheat bread.
Protein foods include anything made from meat poultry, seafood, beans peas, eggs, processed soy products, nuts and seeds.USDA advised that individual should choose the leaner cuts of beef and poultry when eating these protein sources.
Dairy Products
Milk and some other foods made from milk make up the dairy food group. Cheese, soy milk, animal milk and yogurt are members of this group. Some foods that are made from milk are not in the dairy group, such as cream, cream cheese and butter. The USDA recommends choosing low-fat or nonfat dairy foods.
Vegetables and Fruits
The vegetable food includes dark green vegetables, starchy vegetables, red and orange vegetables, beans and peas. Broccoli, corn, carrots, black beans and artichokes are all members of the vegetable group.
Fresh fruit and fruit juice are members of the fruit food group, which includes berries, melons and fruit cocktail. The USDA says that half of every meal should be made from fruits and vegetables.
Functions Of Food
Functions of food can be divided under three mega theme which are: Physiological Functions, Psychological Functions and Socio-Cultural Function.
Physiological functions
Firstly, our body performs several activities- Voluntary and involuntary. There is not a single moment in life when the body is completely at rest and does not require energy. Even when the body is taking rest (i.e. during sleep) energy is required to enhance the involuntary processes of the body like digestion, respiration, circulation, beating of the heart etc.
Energy is also required to carry out professional, household and recreational activities. This energy is supplied from foods like carbohydrates and fats.Having no energy can be compared to a car that has run out of petrol.
Secondly, food provides materials for tissue building, growth and body repair, is mainly supplied through foods like proteins and minerals. The muscles, bones different parts of the body are built up and maintained by the proteins supplied by the food. Minerals like calcium, iron and phosphorus affect the formation of blood and skeleton tissue (bones).
Thirdly, food protects the body against diseases. Here, vitamins play a vital role in regulating the body processes such as growth, eyesight, health of the skin, formation of pr teeth and good digestion. Minerals also act as catalysts for many biological reactions within the body.
Food are required for building of bones, muscular contraction, and transmission of messages through the nervous system and the digestion and utilisation of nutrients in food. Vitamins and minerals are needed for maintaining the general health of the body.
Fourthly, water and roughage in foods act as regulatory foods that are needed for the normal functioning of the body. Water is next to oxygen and it is required in large amount to regulate body processes such as digestion, excretion, maintenance of body temperature and the electrolyte balance. Roughage helps in good bowel movements.
Lastly, Achieving good health is one thing, but keeping it is another. You need to maintain your health, and you need good food in order to do this. For example, your skin is often cut or grazed, your hair falls out constantly and your red and white blood cells die on a regular basis. By consuming the right nutrients, your body will repair itself and stay healthy.
II. Psychological Functions
Foods satisfy certain emotional needs of human beings and act as a source of security. An infant learns security from the way his mother feeds him. Similarly, a growing child gains confidence and a sense of belonging when he/she knows there is food in the house and he/she will be fed. People feel reasonably secure, when they have enough food stored up to take care of them during scarcity.
Food is also an outlet for emotion. As a relief from tension, one may not eat or over eat. For some people, loneliness and boredom are relieved by continuous nibbling at food. Food is also used as a weapon, when an insecure child refuses to eat, thereby drawing the attention of the parents especially the mother.
III. Socio-cultural Function
From ancient times the socio-cultural life of human beings has been revolved around food. Food is used as a symbol of hospitality and friendship throughout the world. We express our hospitality to a guest through an offer of food or drink. In social gatherings, food serves as an instrument for developing social relationships. Here the menu plays an important role, and the nutritive value of it is not given much emphasis.
Every family has its own peculiar meal pattern. This is governed by the social class to which they belongs, the economic condition, religious belief and social attitude. Today, food has brought about an integration of different cultures, race, ideals and thinking of people, by accepting and relishing others dishes.
Thus, for an average man, food is much more, than a substance supplying nutrients for health. It is the sum of his culture and traditions, gratification of pleasure and a relief from stress, a means of communication, security, status this and many more unconsciously expressed in food they chooses.
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