Unit 2: Nutrients and Nutrition

Food Science & Nutrition Notes Third Semester

Nutrients and Nutrition

 


Introduction:

Definition of nutrients:

Nutrients are substances that are essential for the growth, maintenance, and repair of the body’s tissues. These substances are obtained from food and are used by the body for a variety of functions, including energy production, growth and development, and maintenance of bodily functions. Nutrients can be categorized into macro nutrients and micro nutrients. Macro nutrients are those that are required in large amounts and include carbohydrates, proteins, and fats. Micro nutrients, on the other hand, are required in smaller amounts and include vitamins and minerals. Proper nutrition involves consuming a balanced diet that provides all of the necessary nutrients in the appropriate amounts.

Nutrients are essential for the body to function properly and maintain good health. They are the building blocks of our body and provide energy, regulate metabolism, and support growth and repair of tissues. Nutrients are obtained from the food we eat, and they can be classified into two main categories: macro nutrients and micro nutrients.

Macro nutrients are required in larger amounts and include carbohydrates, proteins, and fats. Carbohydrates are the body’s primary source of energy and are found in foods such as grains, fruits, and vegetables. Proteins are essential for the growth and repair of tissues and are found in foods such as meat, fish, eggs, and beans. Fats are important for energy production and the absorption of certain vitamins, and they can be found in foods such as oils, nuts, and seeds.

Micro nutrients are required in smaller amounts and include vitamins and minerals. Vitamins are essential for the proper functioning of the body’s systems and are found in foods such as fruits, vegetables, and fortified cereals. Minerals are important for the maintenance of bone health, fluid balance, and the regulation of certain bodily functions, and they can be found in foods such as dairy products, leafy greens, and whole grains.

Proper nutrition involves consuming a balanced diet that provides all of the necessary nutrients in the appropriate amounts. This means eating a variety of foods from all food groups to ensure that you are getting all of the nutrients your body needs. A deficiency in any nutrient can lead to a range of health problems, so it’s important to ensure that your diet is balanced and includes a variety of nutrient-rich foods.

Micronutrients and Macronutrients:

 

Micronutrients and macronutrients are both essential components of a healthy and balanced diet. Micronutrients are nutrients that the body needs in small amounts, typically less than 100 milligrams per day, but are still essential for proper growth and development, disease prevention, and overall health. Micronutrients include vitamins and minerals, which play a critical role in many of the body’s functions, including immune system function, energy production, and bone health.

Vitamins are organic compounds that the body needs in small amounts to function properly. They play a vital role in many bodily processes, including immune function, energy production, and blood clotting. There are 13 essential vitamins, including vitamins A, B, C, D, E, and K. Each vitamin has its own specific functions and food sources, and a deficiency in any vitamin can lead to serious health problems.

Minerals are inorganic substances that the body needs in small amounts to function properly. They are involved in a wide range of bodily processes, including muscle contraction, nerve function, and bone health. There are two categories of minerals: macrominerals and trace minerals. Macrominerals, such as calcium, phosphorus, and magnesium, are needed in larger amounts, while trace minerals, such as iron, zinc, and copper, are required in smaller amounts.

Macronutrients, on the other hand, are nutrients that the body needs in larger amounts, typically measured in grams or milligrams per day. They provide energy to the body and are essential for growth, development, and overall health. The three main macronutrients are carbohydrates, proteins, and fats.

Carbohydrates are the primary source of energy for the body, and they are found in foods such as grains, fruits, and vegetables. Carbohydrates can be divided into two categories: simple and complex. Simple carbohydrates, such as sugar, are quickly absorbed by the body and provide a quick burst of energy, while complex carbohydrates, such as whole grains, are broken down more slowly and provide a longer-lasting source of energy.

Proteins are essential for the growth and repair of tissues in the body, and they can be found in foods such as meat, fish, eggs, and beans. Proteins are made up of amino acids, which the body uses to build and repair muscle tissue, organs, and other structures.

Fats are an important source of energy for the body, and they play a critical role in the absorption of certain vitamins and minerals. Fats can be divided into two categories: saturated and unsaturated. Saturated fats, which are found in foods such as butter, cheese, and red meat, can increase the risk of heart disease, while unsaturated fats, such as those found in fish, nuts, and seeds, can help to lower the risk of heart disease.

In conclusion, both micronutrients and macronutrients are essential for a healthy and balanced diet. Micronutrients, such as vitamins and minerals, are needed in smaller amounts, while macronutrients, such as carbohydrates, proteins, and fats, are required in larger amounts. A well-balanced diet that includes a variety of nutrient-rich foods is key to ensuring that you are getting all of the essential micronutrients and macronutrients your body needs to function properly and maintain good health.

Introduction of Carbohydrates: Monosaccharide, Oligosaccharides, Polysaccharides, Dietary Fibers, functions of carbohydrates:

Introduction to Carbohydrates:

Carbohydrates are one of the three main macronutrients that provide energy to the body. They are organic molecules that contain carbon, hydrogen, and oxygen, and are commonly found in foods such as grains, fruits, vegetables, and dairy products. Carbohydrates are classified into four main categories based on their chemical structure: monosaccharides, oligosaccharides, polysaccharides, and dietary fibers.

Monosaccharides:

Monosaccharides are the simplest form of carbohydrates, consisting of a single sugar molecule. The most common monosaccharides are glucose, fructose, and galactose. Glucose is the primary source of energy for the body’s cells and is found in many foods, including fruits, vegetables, and grains. Fructose is found in fruits and some vegetables, while galactose is found in dairy products.

Oligosaccharides:

Oligosaccharides are carbohydrates that contain two to ten sugar molecules linked together. They are commonly found in beans, legumes, and some vegetables. Oligosaccharides are not digestible by the body’s enzymes, and instead, they are fermented by bacteria in the colon. This fermentation process produces gases such as methane and hydrogen, which can cause bloating and flatulence in some people.

Polysaccharides:

Polysaccharides are carbohydrates that contain more than ten sugar molecules linked together. They are commonly found in foods such as grains, potatoes, and beans. Polysaccharides can be divided into two main categories: starch and glycogen.

Starch is the primary storage form of carbohydrates in plants and is found in foods such as rice, bread, and pasta. Starch is broken down into glucose during digestion and is used by the body for energy.

Glycogen is the primary storage form of carbohydrates in the body and is found in the liver and muscles. It is broken down into glucose when the body needs energy.

Dietary Fibers:

Dietary fibers are carbohydrates that are not digested by the body’s enzymes and pass through the digestive system relatively intact. They are found in foods such as fruits, vegetables, and whole grains. Dietary fibers can be divided into two main categories: soluble and insoluble fibers.

Soluble fibers, such as pectin and gum, dissolve in water and form a gel-like substance in the digestive tract. This gel-like substance slows down the absorption of glucose, which can help to stabilize blood sugar levels.

Insoluble fibers, such as cellulose and lignin, do not dissolve in water and pass through the digestive system relatively intact. They help to promote regular bowel movements and can help to prevent constipation.

Functions of Carbohydrates:

Carbohydrates are essential for providing energy to the body’s cells. Glucose, the primary form of carbohydrate used for energy, is converted into ATP, which is used by the body’s cells for energy. Carbohydrates also play a role in maintaining blood sugar levels, as they can be broken down into glucose and released into the bloodstream.

In addition to providing energy, carbohydrates also play a role in protein metabolism. When carbohydrates are not available for energy, the body can break down proteins into amino acids, which can be used for energy instead. This can lead to muscle wasting and other health problems.

Dietary fibers, a type of carbohydrate, are important for maintaining digestive health. They help to promote regular bowel movements and can help to prevent constipation. Soluble fibers can also help to lower cholesterol levels and stabilize blood sugar levels.

Carbohydrates also play a role in weight management. Foods that are high in carbohydrates can provide a sense of satiety and help to prevent overeating.

Introduction of Proteins: Amino acids, essential amino acids complete protein, partially, complete protein, incomplete protein, sources of protein, and functions of protein:

Introduction to Proteins:

Proteins are complex organic molecules that are essential for the growth and repair of tissues in the body. They are made up of building blocks called amino acids, which are linked together by peptide bonds. There are 20 different types of amino acids that can be combined in various ways to form different types of proteins.

Amino Acids:

Amino acids are the building blocks of proteins. They contain an amino group (-NH2), a carboxyl group (-COOH), and a side chain (-R) that varies in structure depending on the specific amino acid. There are 20 different types of amino acids, of which 9 are essential amino acids that cannot be synthesized by the body and must be obtained from the diet.

Complete Protein:

A complete protein is a protein that contains all nine essential amino acids in the amounts needed by the body. Complete proteins are usually found in animal-based foods such as meat, fish, poultry, eggs, and dairy products.

Partially Complete Protein:

A partially complete protein is a protein that contains some, but not all, of the essential amino acids in the amounts needed by the body. These proteins are usually found in plant-based foods such as legumes, nuts, and seeds.

Incomplete Protein:

An incomplete protein is a protein that does not contain all of the essential amino acids in the amounts needed by the body. These proteins are usually found in plant-based foods such as grains, fruits, and vegetables.

Sources of Protein:

Protein is found in a variety of foods, including animal-based foods such as meat, fish, poultry, eggs, and dairy products, as well as plant-based foods such as legumes, nuts, seeds, grains, fruits, and vegetables. The amount and quality of protein in these foods can vary widely.

Functions of Protein:

Protein is essential for the growth and repair of tissues in the body. It is used to build and maintain muscles, bones, skin, hair, and nails. Protein is also involved in the production of enzymes, hormones, and other molecules that are necessary for the body’s metabolic processes.

Protein is also important for the immune system, as it is used to produce antibodies that help to fight off infections and diseases. In addition, protein can be used for energy when carbohydrates and fats are not available.

Introduction to Lipids:

Lipids are a group of organic molecules that are insoluble in water but soluble in nonpolar solvents such as alcohol, ether, and chloroform. They include fats, oils, waxes, phospholipids, and sterols. Lipids are an important source of energy for the body, and they also play a role in cell structure and function, hormone production, and insulation.

Fats and oils are the most common types of lipids. They are composed of glycerol and fatty acids, and they are used as a source of energy and as a storage form of energy in the body. Fats and oils can be found in foods such as meat, dairy products, nuts, seeds, and oils.

Phospholipids are a type of lipid that is important for cell structure and function. They are a major component of cell membranes and help to regulate the movement of molecules in and out of cells. Phospholipids can be found in foods such as egg yolks and soybeans.

Sterols are a type of lipid that is important for hormone production and cell membrane structure. The most well-known sterol is cholesterol, which is found in animal-based foods such as meat, eggs, and dairy products.

Functions of Lipids:

Lipids serve a variety of important functions in the body, including:

  1. Energy Storage:Lipids are an efficient form of energy storage, as they contain more energy per gram than carbohydrates or proteins. They are stored in adipose tissue and can be used as a source of energy when glucose levels in the blood are low.

  2. Structural Component:Lipids are an important component of cell membranes, which are made up of a phospholipid bilayer. The hydrophobic nature of lipids helps to form a barrier that separates the inside of the cell from its environment.

  3. Insulation: Adipose tissue, which is made up of fat cells, provides insulation for the body. This helps to regulate body temperature and protect internal organs.

  4. Protection: Lipids can provide protection to internal organs. For example, the layer of adipose tissue around the kidneys and heart helps to cushion them and protect them from damage.

  5. Hormone Production: Lipids are involved in the production of hormones such as estrogen and testosterone, which are important for reproductive and sexual development.

  6. Vitamin Absorption: Certain vitamins, such as vitamins A, D, E, and K, are fat-soluble and require lipids for absorption. Without sufficient lipids, these vitamins may not be absorbed properly.

  7. Brain Function: The brain is composed of approximately 60% fat, and lipids play an important role in brain function. Lipids are involved in the transmission of nerve impulses and the maintenance of brain cell membranes.

  8. Digestion: Lipids are involved in the digestion and absorption of other nutrients such as proteins and carbohydrates. Bile acids, which are made from cholesterol, help to emulsify fats in the small intestine, making them more accessible to digestive enzymes.

In summary, lipids play a crucial role in the body’s energy metabolism, cell structure and function, hormone production, vitamin absorption, brain function, and digestion.

Essential and nonessential fatty acids:

Fatty acids are types of organic compounds that are essential for maintaining good health. They are classified into two categories: essential and non-essential fatty acids.

Essential fatty acids (EFAs) are fatty acids that the body cannot produce on its own, so they must be obtained through the diet. The two main types of essential fatty acids are omega-3 and omega-6 fatty acids. These EFAs are important for the proper functioning of the body, including brain function, growth and development, and maintaining healthy skin and hair.

Omega-3 fatty acids are found in fatty fish, such as salmon, mackerel, and tuna, as well as in nuts and seeds, such as chia seeds and flaxseeds. Omega-6 fatty acids are found in plant-based oils, such as soybean oil, corn oil, and sunflower oil.

Non-essential fatty acids, on the other hand, are fatty acids that the body can produce on its own. These fatty acids are still important for good health, but they are not considered essential because the body can make them as needed. Examples of non-essential fatty acids include palmitic acid and stearic acid.

functions of lipid, cholesterol:

Lipids and cholesterol have several important functions in the body. Here are some of the key functions of these substances:

Lipids:

  1. Energy storage: Lipids are an efficient way for the body to store energy, as they contain more than twice the amount of energy per gram as carbohydrates or proteins.

  2. Insulation: Fat acts as an insulator to help keep the body warm.

  3. Protection: Lipids provide protection to vital organs, such as the kidneys and heart, by acting as a cushion.

  4. Hormone production: Some lipids, such as cholesterol, are used to produce hormones in the body.

  5. Cell membrane structure: Lipids are a key component of cell membranes, helping to maintain their structure and function.

Cholesterol:

  1. Cell membrane structure: Cholesterol is an important component of cell membranes, helping to maintain their fluidity and stability.

  2. Hormone production: Cholesterol is used to produce hormones such as estrogen, testosterone, and cortisol.

  3. Vitamin D synthesis: Cholesterol is needed for the synthesis of vitamin D, which is important for bone health.

  4. Bile production: Cholesterol is a precursor to bile acids, which are necessary for the digestion and absorption of fats.

  5. Nerve function: Cholesterol is important for the normal functioning of nerve cells.

While lipids and cholesterol are important for several functions in the body, it is important to maintain healthy levels of these substances, as high levels can increase the risk of health problems such as heart disease.

Introduction of Vitamins: General functions of water soluble and fat soluble vitamins:

Vitamins are essential micronutrients that the body requires in small amounts for various physiological processes. They play a vital role in maintaining good health and preventing diseases. There are two main categories of vitamins: water-soluble vitamins and fat-soluble vitamins.

Water-soluble vitamins are vitamins that dissolve in water and are not stored in the body for long periods. Any excess amounts of these vitamins are excreted in urine. The water-soluble vitamins include vitamin C and the B vitamins (thiamine, riboflavin, niacin, pantothenic acid, pyridoxine, biotin, folic acid, and cobalamin).

The general functions of water-soluble vitamins are as follows:

  • They act as coenzymes in metabolic reactions, helping enzymes to catalyze chemical reactions in the body.
  • They help in the production of energy from food.
  • They support the immune system and help in the formation of red blood cells.
  • They aid in the maintenance of healthy skin, hair, and eyes.
  • They help in the synthesis of neurotransmitters that regulate mood and behavior.

Fat-soluble vitamins, on the other hand, dissolve in fat and are stored in the body’s fatty tissues and liver. As a result, excess amounts of these vitamins can accumulate in the body and become toxic if consumed in large amounts. The fat-soluble vitamins include vitamins A, D, E, and K.

The general functions of fat-soluble vitamins are as follows:

  • They help in the absorption of calcium and phosphorus, promoting bone health and growth.
  • They act as antioxidants, protecting cells from damage by free radicals.
  • They help in the regulation of blood clotting and wound healing.
  • They support healthy vision, skin, and immune function.
  • They aid in the production of red blood cells and prevent anemia.

Introduction of Minerals:

General functions of minerals:

Minerals are essential micronutrients that the body requires in small amounts for various physiological processes. They play a vital role in maintaining good health and preventing diseases. There are two main categories of minerals: major minerals and trace minerals.

Major minerals are minerals that the body requires in relatively large amounts, typically at least 100 milligrams per day. These include calcium, phosphorus, potassium, sodium, chloride, and magnesium.

The general functions of major minerals are as follows:

  • They help in the formation and maintenance of strong bones and teeth.
  • They help in the regulation of fluid balance in the body.
  • They are involved in the contraction and relaxation of muscles.
  • They support nerve function and communication.
  • They are essential for the production of energy from food.

Trace minerals, on the other hand, are minerals that the body requires in smaller amounts, typically less than 100 milligrams per day. These include iron, zinc, copper, selenium, iodine, manganese, and fluoride.

The general functions of trace minerals are as follows:

  • They are involved in the formation of enzymes, which are proteins that facilitate chemical reactions in the body.
  • They act as cofactors for various enzymes, helping to regulate their activity.
  • They support the immune system and help in the prevention of infections.
  • They aid in the formation of hormones and other signaling molecules.
  • They are involved in the production of red blood cells and hemoglobin, which carries oxygen throughout the body.

Introduction of Water:

General functions of water:

Water is a vital nutrient for the human body and plays several important roles in maintaining optimal health. Here are some of the general functions of water:

  1. Regulation of body temperature: Water helps regulate body temperature by releasing heat through sweat. It helps cool the body down during exercise or hot weather.

  2. Transportation of nutrients: Water acts as a medium to transport nutrients, oxygen, and hormones to cells and organs throughout the body. It also helps remove waste products and toxins from the body.

  3. Lubrication of joints: Water helps lubricate and cushion joints, reducing friction and damage. This is particularly important for people with arthritis or joint pain.

  4. Digestion and absorption of food: Water helps dissolve and break down food in the digestive tract, making it easier for the body to absorb nutrients from food.

  5. Protection of tissues and organs: Water helps protect vital organs and tissues, such as the brain and spinal cord, by providing a cushioning effect.

  6. Maintenance of blood pressure: Water plays a critical role in maintaining blood pressure regulating the balance of electrolytes, such as sodium and potassium, in the body.

Loss of nutrients during blanching:

Blanching is a process of briefly boiling vegetables or fruits in water or steam, followed by rapid cooling in ice water. It is commonly used to prepare vegetables for freezing or canning, as it can help preserve the color, texture, and flavor of the food.

While blanching can help inactivate enzymes that can cause spoilage and remove surface dirt and microorganisms, it can also cause some loss of nutrients. Water-soluble vitamins, such as vitamin C and B vitamins, can leach out into the blanching water, especially if the vegetables are blanched for a long time or at a high temperature.

The extent of nutrient loss during blanching depends on various factors, such as the type of vegetable, blanching time and temperature, and the volume of water used. However, the loss of nutrients during blanching is generally considered to be relatively minor compared to the overall nutrient content of the food.

To minimize nutrient loss during blanching, it is recommended to use minimal water and blanch for the shortest possible time. Additionally, you can use the blanching water to make soups or sauces, or consume it as a nutrient-rich broth, to reduce nutrient waste.

Heat processing and milling:

Heat processing and milling are two common methods used in the food industry to preserve and transform food products.

Heat processing involves the application of heat to food products, typically through cooking or sterilization, to destroy microorganisms and enzymes that can cause spoilage or foodborne illnesses. Heat processing can also improve the texture, flavor, and color of some foods. Common heat processing techniques include pasteurization, canning, baking, and frying.

However, heat processing can also lead to nutrient loss, especially for heat-sensitive vitamins such as vitamin C and thiamin. Overcooking or high-temperature cooking can also produce harmful compounds such as acrylamide, which forms in starchy foods such as potato chips and French fries when they are cooked at high temperatures.

Milling is a process used to grind grains, seeds, and other dry ingredients into flour or meal. The milling process involves breaking the grain or seed into smaller pieces and then grinding it to the desired fineness. Milling can help increase the shelf life of grains and make them easier to digest. However, milling can also result in nutrient loss, especially for grains that have been stripped of their outer layers, such as refined flour.

To minimize nutrient loss during milling and heat processing, it is important to use appropriate processing methods and techniques. For example, using lower cooking temperatures and shorter cooking times can help preserve more nutrients in food products. Choosing whole grains and minimizing the use of refined grains can also help increase the nutrient content of milled products.

Introduction to Balanced diet: Recommended Dietary Allowances (RDA), Malnutrition:

A balanced diet is a diet that includes a variety of foods from different food groups in the right proportion to meet the body’s nutritional needs. It is essential for maintaining good health, preventing chronic diseases, and promoting optimal growth and development.

The Recommended Dietary Allowances (RDA) are a set of nutrient intake recommendations developed by the National Academy of Sciences that are used to assess and plan diets for healthy individuals. The RDA values are based on age, sex, and other factors, and they provide guidance on the amount of essential nutrients that individuals need to consume to maintain good health.

Malnutrition

Malnutrition occurs when the body does not receive the necessary nutrients to maintain good health. It can result from consuming an unbalanced diet that lacks essential nutrients, overeating, or under-eating. Malnutrition can lead to a range of health problems, including stunted growth and development, weakened immune system, and increased risk of chronic diseases.

A balanced diet should include a variety of foods from different food groups, including fruits, vegetables, whole grains, lean proteins, and healthy fats. It should also limit the intake of processed and high-calorie foods, such as sugary drinks and snacks, fried foods, and desserts. By following a balanced diet that meets the RDA values for essential nutrients, individuals can help maintain good health and prevent malnutrition.

 

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