Digestive System

Digestive System (Metabolism of food)

The conversion of food into energy is a process called metabolism.  There are two types of metabolism – anabolic, metabolism all the chemical changes that take place in the cells after the end products of digestion are absorbed. The Metabolism of food.  The nutritive value of food. The qualitative and quantitative requirements for food at different ages and developmental levels to meet physiological changes & activity needs. The changes in nutrient & food requirements that accompany or in the reduced risks of degenerative conditions &, The economic, psychological, social & cultural factors that affect the selection & eating of foods.

Look at following figure it shows you the essential parts of the digestive tract.

Metabolism of food

The liver and pancreas are not a part of the digestive tract but they secrete certain juices or secretions which do play a role in the process of digestion and absorption of food.

DIGESTION OF FOOD

Digestion takes place step-by-step at various sites in the digestive tract.

1. Mouth: - The process of digestion begins in the mouth where food is chewed by the teeth and mixed with saliva. While the food is still in the mouth, it is acted upon by and enzyme, amylase, which acts only on cooked carbohydrates and partially digests them or breaks them up into smaller units.
2. Stomach: - The chewed food mixed with Saliva the passes into the stomach through the tube-like structure called the oesophagus. It gets mixed with the digestive juice present in the stomach called gastric juice. Besides enzymes and water, gastric juice also contains small amounts of an acid called hydrochloric acid which makes it acid in nature. Mixing of food with the gastric juice converts the food into a thin soup-like consistency. Gastric juice contains and enzyme which acts on proteins and brings about their partial digestion.
3. Small intestine: - The partially digested mass of food passes from the stomach into the small intestine. The small intestine not only contains intestinal juice but also secretions from the liver and pancreas. The secretion from the liver is called bile and from the pancreas is known as pancreatic juice. Bile aids in the digestion and absorption of fats. Both pancreatic intestinal juices contain enzymes which break down fats, proteins and carbohydrates into simpler substances. These substances ultimately reach the bloodstream.
4. Large intestine: - The food which is not absorbed in the small intestine along with a large amount of water passes on to the large intestine. Here most of the excess water is reabsorbed and the remaining water and solid matter is eliminated from the body as faces.

ABSORPTION OF FOOD

Absorption takes place in the small intestine. The end products of digestion or the nutrients present in the small intestine can be used by the body only when they enter the bloodstream. This process of movement of digested food or nutrients across the intestinal wall to the bloodstream is termed absorption of food. The wall of the small intestine is made up of numerous folds or finger-like projections known as with.

UTILIZATION OF FOOD

Utilized for specific functions the absorbed end products or the nutrients from the food we eat further undergo chemical changes. They are broken down to release energy or are used to form complex substances. These substances can then be used to manufacture more complex or can be stored in the body. 

Deficiency and Disease of Proteins

Deficiency and Disease of Proteins

Marasmus               and                Kwashiorkor

Both marasmus and kwashiorkor are diseases that arise due to an inadequate diet and starvation. There are subtle differences between the two conditions. Let us take a look at what they are:

 Symptoms

 A kid who is suffering from marasmus can be identified at a glance. He will have dry and lose skin hanging over the glutei. The child loses adipose or fat tissue from normal areas of the body like the buttocks and the thighs. The child is usually irritable and has an exceptionally strong appetite. The child also has alternated layers of non pigmented or pigmented hair.

A patient with kwashiorkor suffers from damaged absorption. He may also display abnormal burns, nephrosis or a chronic liver disease. The child may also suffer from loss of muscular mass, edema or other immunodeficiency symptoms. The child also suffers from vomiting, infections and diarrhea.

Causes

Marasmus is caused by a severe nutritional deficiency in general. It is usually found in very young infants and very young children. It can be prevented by breastfeeding. It is actually caused by the total or partial lack of nutritional elements in the food over a period of time.

Kwashiorkor is actually the result of a lack of protein in the diet. It is different from marasmus, which is a total lack of nutrition in the diet. The term kwashiorkor is derived from an African term which means ‘first- second child’. This is because it usually affects children who are weaned away because of the birth of a second child.

Who does it affect?

Due to the reason behind the condition, marasmus usually affects very young children. However, kwashiorkor affects slightly older children.

Kwashiorkor is usually rampant in those parts of the world where babies become deficient in proteins because of their weaning habits. The diets do not lack in calories as is typical in children suffering from  marasmus.  It is found in third world countries suffering from starvation. However, it can affect anyone who suffers from a lack of protein in the diet, and an excess of carbohydrates

Summary:

Ø  Marasmus patients suffer from a peeling and alternately pigmented skin. Kwashiorkor patients are characterized by a distended stomach, burns on the skin and diarrhea.

Ø  Marasmus affects kids because of a lack of nutritional elements in the diet. Kwashiorkor affects kids who do not receive enough protein in the diet.

Ø  Marasmus affects infants and very young kids. Kwashiorkor affects kids who are a bit older.

Ø  Marasmus patients need to be treated with additional doses of vitamin B and a nutritious diet. Kwashiorkor patients are treated by adding more protein in their diet.

Proteins Importance in Nutrition

Proteins (Importance in Nutrition)

Proteins are organic macromolecules made up of linear chains of amino acids. However, while a protein’s basic structure is a linear amino acid chain, the final structure of a protein is not linear. Instead, the protein’s amino acid sequence—and the physical and chemical properties of the amino acids and of the entire protein molecule - influences how it folds into a three dimensional shape. The amino acid sequence of a protein is determined by the base pair sequence in the gene which codes for the protein. There are twenty ‘standard’ amino acids (along with one or two non-standard proteins which are not coded for by DNA in the usual sense).

What is Protein?

Largest constituent of body weight after water 20% of our body weight.  Found throught the body. In muscle, bone, skin, hair, and virtually every other body part or tissue. Makes up the enzymes that power many chemical Reactions and the hemoglobin. At least 10,000 different proteins make you what   you are and keep you that way.

Proteins as Enzymes

The function of proteins as enzymes is perhaps their best-known function. Enzymes are catalysts—they initiate a reaction between themselves and another protein, working on the molecule to change it in some way. The enzyme, however, is itself unchanged at the end of the reaction. Enzymes are responsible for catalyzing reactions in processes such as metabolism, DNA replication, and digestion. In fact, enzymes are known to be involved in some 4,000 bodily reactions.

Proteins in Cellular Signaling and Molecular Transport Cells signal one another for an enormous variety of reasons, the most basic of which is simply to coordinate cellular activities. Signaling is how cells communicate with one another, allowing such essential processes as the contraction of the heart muscle to take place.

           

Proteins are important in these processes due to their ability to bind other molecules—a protein produced by one cell may bind to a molecule produced by another, thus providing a chemical signal which allows the cells to provide information about their state. Proteins are also involved in molecular transport.

A prime example of this is the protein called hemoglobin, which binds iron molecules and transports them in the blood from the lungs to organs and tissues throughout the body.

Functions of Proteins

Ø  Protein has a range of essential functions in the body, including the following:

Ø  Required for building and repair of body tissues (including muscle)

Ø  Enzymes, hormones, and many immune molecules are proteins

Ø  Essential body processes such as water balancing, nutrient transport, and muscle contractions require protein to function.

Ø  Protein is a source of energy.

Ø  Protein helps keep skin, hair, and nails healthy.

Ø  Protein, like most other essential nutrients, is absolutely crucial for overall good health.

Ø  About half of the protein consumed daily is converted into enzymes, the specialized "worker proteins" that regulate the speed of biological reactions in your body and permit it to perform functions such as digesting food and assembling or dividing molecules to make new cells and chemical substances. To perform these functions, enzymes often need specific vitamins and minerals.

So what does protein do?

To make all the proteins that the body needs, 22 different amino acids are required. Nine are considered to be essential, meaning they are not synthesized by the body and must be obtained from food. Our bodies can produce the other 13 from fats, carbohydrates, and other amino acids. So, these are referred to as non-essential amino acids.

Protein Needs Various Stages

Daily Protein requirement of an adult 1gm/kg body wt, but in following conditions need of protein increases:  Growth needs of children -1.5 gm/kg body wt. Development of maternal tissues and the fetus during pregnancy and lactation – 1.75gm/kg body wt.

Infections, immobilization, surgery, burns, and other injuries. Emotional stress increases protein breakdown. Frequent intestinal infection A poor state of Nutrition.

Food Sources of Proteins

Animal (food) products are rich sources of protein. Meat, milk and milk products, egg, poultry, and fish, contain balanced level of amino acids. Protein can also be obtained from plant (vegetable) food items such as legumes (soybean and soybean products, peas, beans etc.), and nuts.

Food Sources of Proteins
Milk and milk products
Milk(Cows)	3.2g/100
Milk(Buffalos)	4.3 g/100
Curd(Cow’s milk)	3.1 g/100
Paneer (Cottage cheese)	18.3 g/100
Khoa(Cow’s milk)	20.0 g/100
Pulses
Soyabean	43.2 g/100
Others	17.1 – 25.1 g/100
Flesh Foods
Egg	13.3 g/100
Fish(Rohu)	16.6 g/100
(Hilsa)	21.8 g/100
Goat’s meat	21.4 g/100
Fowl	25.9 g/100
Nuts
Groundnut	25.3 g/100
Cashew nut	21.2 g/100

Usage of Proteins

It is possible to consume too much protein. The amount of protein needed for good health varies.

Ø  An average healthy adult man or woman needs about 0.8 grams of protein per every kilogram (2.2 pounds) of body weight.

Ø  As you grow older, new proteins are synthesized less efficiently, and muscle mass (protein tissue) diminishes while fat content stays the same or rises. This is why muscle seems to "turn to fat" in old age.

Ø  Infants, adolescents, pregnant women, individuals with injuries, and athletes may often require more protein on a daily basis.

RDA of Protiens

Ø  Children - Age - 4-6 - 30/24 gms

Ø  Children - Age - 7-10 - 36/24 gms

Ø  Males - Age - 15-18 - 54/59 gms

Ø  Males - Age - 19-24 - 54/58 gms

Ø  Males - Age - 25-50 - 56/63 gms

Ø  Males - Age - 50-++ - 56/63 gms

Ø  Females - Age - 15-18 - 48/44 gms

Ø  Females - Age - 19-24 - 46/46 gms

Ø  Females - Age - 25-50 - 46/50 gms

NUTRITION AND HEALTH

NUTRITION AND HEALTH

NUTRITION IS THE RELATIONSHIOP OF FOOD TO THE WELL BEING OF THE HUMAN BODY.

{Macronutrients Micronutrients}

Introduction

Nutrition

 Food is essential because it contains substances which perform important functions in our body. These essential substances contributed by our food are called nutrients. If these nutrients are not present in our food in sufficient amounts, the result is ill health and in some cases, even death. Food also contains many substances which are non-nutrients e.g. coloring and flavoring in food. The science of foods the nutrients and other substances in their action. Interaction and balance is relationship to health and disease; the process by which the organism ingests, absorbs, transports and utilizes nutrients and disposes of their end products. In addition, nutrition must be concerned with the social, economic, cultural and psychological implications of food and eating.  Food, as you know, contains nutrients as well as substances which are non-nutrients. The body needs each nutrient is specific amounts. Some are needed in relatively larger amounts (THE MACRONUTRIENTS) and some in smaller amounts (THE MICRONUTRIENTS) But they are all equally essential for our health. Each nutrient plays a significant role in the body. The mineral, calcium, for example, helps build strong bones and teeth.   Nutrition is about why you eat, what you eat and how food you get affects your body and your health. Each one of us has special needs and goals. If you do not know where are going, will not know when you have arrived, if you arrive at all. Many people plunge ahead with a nutrition plan without first checking to see what is needed or will even work. Each of us must assess our own nutritional status to determine what is needed and where we are going before planning our life long plan of care.

Approximately 60 % of our body weight is water, 20% of our body is fat, and 20% of our body weight is a combination of mostly protein plus carbohydrates, minerals and vitamins.

Functions of Nutrients

What is the purpose of the process of digestion? It is through this process that the complex substances in food are broken down into simpler substances which the body can take in and use. Some of these complex substances such as carbohydrates, proteins and fats undergo some change during digestion. However, water, mineral and vitamins present in the food can be absorbed directly without undergoing any digestive change. Digestion and absorption take place in the digestive tract of the body.   Nutrients from food are absorbed by the body as it passes through the digestive system. Food is essential because it contains substances which perform important functions in our body. These essential substances contributed by our food  are called nutrients. If these nutrients are not present in our food in sufficient amounts, the result is ill health and in some cases, even death. Food also contains many substances which are non-nutrients e.g. coloring and flavorings sub­stances in food.

{Food is, therefore, a complex mixture of different nutrients and non-nutrients.}

Ø  Nutrients are essential for cell growth, maintenance and repair.

Ø  Nutrients provide energy to enable your body to function efficiently.

Ø  Nutrients, along with fiber and water, are essential to your good health.

Although nutrients can work alone, each depends upon the others to be the most effective. The main nutrients are the macronutrients, carbohydrates, proteins, and fats – and the micronu­trients, vitamins and minerals. 

Micronutrients

Micronutrients

                            Micronutrients are as important for our health and well-being as macronutrients. They are, in fact, remarkable substances. We require them in such small amounts and yet crucial functions they perform.

What Micronutrients Do?

Vitamins and minerals do not in themselves provide energy, but macronutrients depend on them to regulate the release of energy from food.

Vitamins are organic substances. They activate enzymes, which are proteins that act as catalysts to speed up biological reactions that take place in your body. Your body produces a certain amount of vitamins D and K, but all other vitamins come from your diet.

Minerals are inorganic substances that originate from rocks and ores and enter the food chain through the soil.

Functions of Micronutrients

Ø  We get minerals either by eating plants grown on mineral-rich soil or by eating animals that have fed on these plants. Calcium, magnesium and phosphorus are the major constituents of bone. Sodium and potassium control your body's water balance. Other minerals (chromium, iron, and magnesium) are needed for various chemical processes to take place in the body. 

Macronutrients

Macronutrients

                            You know that nutrients are essential constituents of food that must be supplied to the body in suitable amounts. There are around 40 essential nutrients which (based on their chemical structure and properties) are placed in five categories. These are carbohydrates, fats, proteins, vitamins and minerals. Water has the unique status of a food as well as that of macronutrient.

Nutrients required by Body

Macronutrients	Micronutrients
Proteins	Vitamins
Carbohydrates	Minerals
Essential Fatty Acids
Dietary Fiber
Water

What Macronutrients Do?

Macronutrients Are Essential for Good Health: Macronutrients are nutrients that Provide calories or energy needed for growth, support of the protein absorption, metabolism, and for other body functions. Since “macro” means large, macronutrients are nutrients needed in large amounts.

Functions of Macronutrients

Ø  They assist in breaking down carbohydrates and fats, which provide energy to the body.

Ø  They assist in the absorption of protein, which provides the building blocks necessary for cell growth and repair.

Malnutrition

What is it?

Malnutrition is a disparity between the amount of food and other nutrients that the body needs and the amount that it is receiving. This imbalance is most frequently associated with under nutrition, the primary focus of this article, but it may also be due to over nutrition.

Before we go any further, we need to be familiar with the “Malnutrition”. Malnutrition is an important of health resulting from a deficiency, excess or imbalance of nutrients. In other words, malnutrition refers to both under nutrition and over nutrition. Under nutrition means a deficiency of lack of one or more nutrients and over nutrition mean excess of one or more nutrients. Both under nutrition and over nutrition results in till health.

Example:-

Ø  Under nutrition is vitamin A deficiency. When young children do not consume enough vitamin A-rich foods, their eyes are affected and ultimately blindness results.

Ø  A disease that we easily relate to over nutrition is extreme overweight or obesity. When a person takes in more energy than he is able to spend on his daily activities, he accumulates fat it the body and his weight increaser. If the weight increases substantially, the person becomes obese.

What are the causes of malnutrition?

Malnutrition, the result of a lack of essential nutrients, resulting in poorer health, may be caused by a number of conditions or circumstances. In many developing countries long-term (chronic) malnutrition is widespread - simply because people do not have enough food to eat. 

Ø  Poor diet - if a person does not eat enough food, or if what they eat does not provide them with the nutrients they require for good health, they suffer from malnutrition. Poor diet may be caused by one of several different factors.

Ø  Mental health problems - some patients with mental health conditions, such as depression, may develop eating habits which lead to malnutrition. Patients with anorexia nervosa or bulimia may develop malnutrition because they are ingesting too little food.

Ø  Mobility problems - people with mobility problems may suffer from malnutrition, simply because they either cannot get out enough to buy foods, or find preparing them too arduous.

Ø  Digestive disorders and stomach conditions - some people may eat properly, but their bodies cannot absorb the nutrients they need for good health. Examples include patients with ulcerative colitis. Such patients may need to have part of the small intestine removed.

Ø  Alcoholism - an alcoholic is a person who suffers from alcoholism - the body is dependent on alcohol. Alcoholism is a chronic (long-term) disease. Individuals who suffer from alcoholism can develop gastritis, or pancreas damage.