Balanced-diet
By Engr. Meerub Khalil

Definition: A balanced-diet is a diet which contains the right amount or right quantity of essential nutrients; nutrients make the human body healthy.

Example:
Following are the examples of five nutrients that are required in a balanced diet.

Carbohydrates
Proteins
Fats
Minerals
Vitamins

Discussing each nutrient in detail one by one.

Carbohydrates

Carbohydrates are essential for human body due to several reasons. Carbohydrates are the main source of energy, proper brain function, helps in improving athletic performance of athletes, and dietary fibers.
Sources: Wheat, milk, sweet fruits, oats, barley, pulses.

Carbohydrates

Carbohydrates Classification

Carbohydrates can be classified into four main categories based on their chemical structure: monosaccharides, disaccharides, oligosaccharides, and polysaccharides. Let's explore each class in detail, along with examples:

(a) Monosaccharides
Monosaccharides are the simplest form of carbohydrates and cannot be broken down into smaller units through hydrolysis.

Glucose: Also known as blood sugar, glucose is a primary energy source for cells and a key player in metabolism.

Fructose: Found in fruits, honey, and some vegetables, fructose is the sweetest naturally occurring sugar.

Galactose: These are found in dairy products.

(b) Disaccharides
Disaccharides are formed by the condensation of two monosaccharide units. This results in the formation of glycoside bond. Example of disaccharides include:

Sucrose: Common table sugar composed of glucose and fructose. It is obtained by sugarcane, sugar beet, and some sweet fruits.

Lactose: Found in milk and dairy products. Lactose contains glucose and galactose. Some individual are lactose intolerant, that means they lack the enzyme that is required to digest lactose.

Maltose: A sugar produced by the breakdown of starch like the enzymes that are found in malt or saliva. Maltose contains two units of glucose.

(c) Oligosaccharides:
Oligosaccharides are carbohydrates composed of 3 to 10 monosaccharide units joined by glycoside bonds. They are commonly found in legumes, beans, and certain vegetables. Examples include:

Raffinose: Present in beans, cabbage, and brussels sprouts, raffinose consists of glucose, fructose, and galactose.

Stachyose: Found in legumes (any plant from Fabaceae family that would include its leaves, stem, and pods) like lentils and soybeans, stachyose consists of two galactose units, one fructose unit, and one glucose unit.

(d) Polysaccharides:
Polysaccharides are complex carbohydrates composed of numerous monosaccharide units linked by glycosidic bonds. They are generally insoluble in water and serve as storage or structural molecules. Common examples include:

Starch: Found in plants, starch is a storage polysaccharide made up of glucose units. It is a significant source of dietary carbohydrates for humans.

Glycogen: Also a storage polysaccharide, glycogen is abundant in animals and serves as the primary energy reserve in the liver and muscles.

Cellulose: The most abundant organic compound on Earth, cellulose is a structural polysaccharide found in plant cell walls. Humans lack the enzymes to digest cellulose effectively, but it contributes to dietary fiber.
Proteins
Proteins are also one of the sources of energy for human body. They are essential for building of muscles and tissues. They help in repairing and healing body.

Sources: Examples of sources of protein in a healthy, balanced diet include meat, milk, fish and seafoods, dairy products, eggs etc.

Proteins

Classification of Proteins

Proteins can be classified into several categories based on their structure, function, and shape. Here are some common classifications of proteins:

(a) Fibrous Proteins
Fibrous proteins have a long, filamentous structure, and their primary function is to provide structural support and strength to cells and tissues. Examples include:

Collagen: The most abundant protein in the body, collagen provides strength and structure to connective tissues, such as skin, tendons, ligaments, and bones.
Keratin: Found in hair, nails, and the outer layer of skin, keratin provides toughness and protection.
Fibrin: Essential for blood clotting, fibrin forms a fibrous network that helps in wound healing.

(b) Globular Proteins
Globular proteins have a compact, rounded shape, and their primary function is to carry out specific biological functions within cells. Examples include:

Enzymes: Proteins that catalyze biochemical reactions, such as amylase, lipase, and DNA polymerase.
Hemoglobin: Found in red blood cells, hemoglobin transports oxygen from the lungs to body tissues.
Insulin: A hormone produced by the pancreas, insulin regulates blood sugar levels.

(c) Primary and Secondary derived proteins:
Proteins that undergo minimal alterations in their structure and properties are known as primary derived proteins. Peptide bonds are largely preserved, with little to no hydrolytic breakdown. Notable examples of primary derived proteins include fibrin, which is derived from fibrinogen, and myosan, which is a modified form of myosin.

On the other hand, secondary derived proteins are the result of significant modifications to the structure and properties of protein molecules. The peptide bonds within these proteins experience progressive hydrolytic cleavage. Proteoses and peptones serve as illustrations of secondary derived proteins.
Fats
A moderate quantity of fat is a vital component of a nutritious and well-rounded diet. Fat serves as a provider of necessary fatty acids, which the body cannot produce on its own. Moreover, fats helps in the absorption of fat-soluble vitamins like vitamin A, vitamin D, vitamin E, and vitamin K.
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Sources: Examples of sources of fat in a healthy, balanced diet include vegetable oils like olive, canola, sunflower, soy, and corn oils. Additionally, nuts, seeds, and fish are also rich in beneficial fats.
Healthy Fats

Classification of Fats

Fats, also known as lipids, can be classified into several categories based on their chemical structure and properties. Here are some common classifications of fats:

(a) Saturated Fats
Saturated fats are composed of fatty acids that have no double bonds between carbon atoms. They are typically solid at room temperature and are primarily found in animal products such as meat, dairy, and some tropical oils like coconut oil and palm oil. Consuming excessive amounts of saturated fats has been associated with an increased risk of cardiovascular diseases.

(b) Unsaturated Fats
Unsaturated fats contain one or more double bonds between carbon atoms in the fatty acid chains. They are usually liquid at room temperature and can be further categorized into two types:

Monounsaturated Fats: Monounsaturated fats have one double bond in the fatty acid chain. They are found in various plant-based oils such as olive oil, canola oil, and avocado oil. Monounsaturated fats are considered heart-healthy and may help reduce the risk of heart disease when consumed in moderation.

Polyunsaturated Fats: Polyunsaturated fats have two or more double bonds in the fatty acid chain. They are commonly found in vegetable oils, including sunflower oil, soybean oil, and corn oil. Polyunsaturated fats can be further classified into two subcategories:

Omega-6 Fatty Acids: These fats are abundant in many vegetable oils and are essential for the body. However, excessive consumption of omega-6 fatty acids relative to omega-3 fatty acids may have inflammatory effects.

Omega-3 Fatty Acids: These fats are crucial for maintaining overall health and are typically found in fatty fish (e.g., salmon, mackerel, sardines) as well as flaxseeds, chia seeds, and walnuts. Omega-3 fatty acids have been associated with various health benefits, including cardiovascular health and brain function.

(c) Trans Fats: Trans fats are artificially produced fats created through a process called hydrogenation, which converts liquid vegetable oils into solid fats. Trans fats have been extensively used in processed foods to improve texture and shelf life. However, they have been found to raise "bad" LDL cholesterol levels and increase the risk of cardiovascular diseases. Many countries have implemented regulations to reduce or eliminate the use of trans fats in food products.
Minerals
Minerals are essential nutrients required by the human body for various physiological functions. They are inorganic substances that cannot be synthesized by the body and must be obtained through diet. Here are some important minerals and their functions in the human body:

(i) Calcium

Necessary for: Bones, teeth, blood clotting and for healthy nerve functioning
Sources: Milk, spinach, dates, avocados
Deficiency: Leads to weakening in human body, bleeding from teeth

(ii) Potassium

Necessary for: muscles, health of heart and for healthy nerve functioning
Sources: Apples, dates, bananas, milk
Deficiency: Pains in muscles

(iii) Copper

Necessary for: Formation of hemoglobin
Sources: Meat, eggs (eggs yolk), copper utensils (but not excessive use)
Deficiency: Bone abnormalities, anemia, impaired growth and development

(iv) Iron

Necessary for: Essential for working of hemoglobin
Sources: Milk, vegetables, dates, dry fruits, red meat, red beans
Deficiency: Fatigue and weakness, pale skin, compromised immune system

There are other many examples of minerals like fluorine, sodium, zinc etc.

(Note: The 5th nutrient vitamins, is already discussed in detail. Link: vitaminsz.blogspot.com)