Human Nutrition

Nucleic acids are crucial molecules found in all living organisms, playing a central role in storing and transmitting genetic information. They come in two main forms: DNA and RNA. DNA holds the genetic instructions necessary for an organism's development, growth, and functioning, while RNA acts as a messenger, carrying out DNA's instructions to produce proteins. These molecules are made up of smaller units called nucleotides, each consisting of a sugar, a phosphate group, and a nitrogenous base. The sequence of these bases determines the unique genetic code of an individual, influencing traits and characteristics.

Fiber, also known as dietary fiber or roughage, refers to the indigestible portion of plant-based foods that passes through the digestive system relatively unchanged. It is primarily found in fruits, vegetables, whole grains, legumes, nuts, and seeds. Fiber comes in two main types: soluble and insoluble. Soluble fiber dissolves in water and forms a gel-like substance in the digestive tract, helping to lower cholesterol levels and regulate blood sugar levels. Insoluble fiber does not dissolve in water and adds bulk to stool, aiding in digestion and preventing constipation. Both types of fiber contribute to overall digestive health, promote regular bowel movements, and can help prevent certain chronic diseases such as heart disease, diabetes, and certain types of cancer.

Minerals are essential nutrients that the body needs in small amounts to function properly. They play crucial roles in various bodily processes, including building strong bones and teeth, controlling the amount of water in the body, supporting nerve function, and maintaining healthy metabolism. There are two main categories of minerals: macro-minerals, which are needed in larger quantities, and trace minerals, which are required in smaller amounts. Common macro-minerals include calcium, magnesium, phosphorus, potassium, sodium, and chloride, while examples of trace minerals include iron, zinc, copper, selenium, iodine, and chromium. These minerals are obtained through the diet, primarily from foods like fruits, vegetables, whole grains, nuts, seeds, dairy products, and lean meats.

Monosaccharides are simple sugars, which are the most basic form of carbohydrates. They consist of single sugar molecules that cannot be broken down further into smaller sugars. Common examples of monosaccharides include glucose, fructose, and galactose. These sugars are easily absorbed by the body and serve as a quick source of energy. Monosaccharides are found naturally in fruits, vegetables, and honey, and they are also added to processed foods as sweeteners. In addition to providing energy, monosaccharides play important roles in cellular processes and are essential for overall health and well-being.

Fructose is a type of sugar, classified as a monosaccharide, that is naturally found in fruits, honey, and certain vegetables. It is known for its sweet taste and is often used as a sweetener in processed foods and beverages. When consumed, fructose is absorbed into the bloodstream and transported to the liver, where it is processed and converted into glucose or stored as glycogen for energy. While fructose can provide energy like other sugars, excessive intake, particularly from added sugars in processed foods, has been associated with negative health effects, including obesity, type 2 diabetes, and fatty liver disease.

Galactose is a type of sugar, classified as a monosaccharide, that is less commonly found in nature compared to glucose and fructose. It naturally occurs in dairy products like milk and yogurt, as well as in certain fruits and vegetables. Galactose is less sweet than glucose and fructose and plays a role in making lactose, the sugar found in milk. Once ingested, galactose is broken down in the body and changed into glucose, which serves as a primary source of energy for cells.

Polysaccharides are complex carbohydrates made up of multiple sugar molecules linked together. They serve as a major source of energy and play important structural roles in living organisms. Common examples of polysaccharides include starch, glycogen, and cellulose. Starch, found in foods like potatoes, rice, and bread, serves as a storage form of energy in plants and is a major source of carbohydrates in the human diet. Glycogen, stored in the liver and muscles, serves as a short-term energy reserve in animals and humans. Cellulose, found in plant cell walls, provides structural support and dietary fiber, aiding in digestion. Polysaccharides are important for providing energy, supporting cellular structure, and maintaining overall health.

Triglycerides are a type of fat found in the blood and are the main form of stored fat in the body. They are composed of three fatty acids attached to a glycerol molecule. After eating, the body converts any calories it does not need immediately into triglycerides, which are stored in fat cells and released for energy between meals. High levels of triglycerides can increase the risk of heart disease and are often associated with other conditions like obesity, type 2 diabetes, and high cholesterol. Maintaining healthy triglyceride levels involves eating a balanced diet, exercising regularly, and avoiding excessive consumption of sugary and fatty foods.

Glycerol, also known as glycerin, is a simple, sweet-tasting compound that is a key part of triglycerides, the main components of fats. It is a colorless and odorless liquid found naturally in fats and oils. In the body, glycerol is released when triglycerides are broken down for energy. It can also be converted into glucose by the liver to provide energy. Besides its role in fat processing, glycerol is used in various food, pharmaceutical, and cosmetic products due to its moisturizing and sweetening properties. Its ability to retain moisture makes it a common ingredient in skincare products and food items.

Disaccharides are a type of carbohydrate made up of two linked sugar molecules that provide a quick source of energy. Common examples include sucrose, which is table sugar; lactose, which is milk sugar; and maltose, which is malt sugar. Sucrose is found in many plants and is commonly used as a sweetener. Lactose is found in dairy products and is the main sugar in milk. Maltose is found in certain grains and is produced during the breakdown of starch. When consumed, disaccharides are broken down into their simpler sugar components by digestive enzymes before being absorbed into the bloodstream.

Sucrose, commonly known as table sugar, is a disaccharide composed of glucose and fructose molecules. It is naturally found in many plants, with high concentrations in sugar cane and sugar beets, which are the primary sources for commercial sugar production. Sucrose is widely used as a sweetener in foods and beverages due to its pleasant taste and ability to enhance flavors. When consumed, sucrose is broken down by digestive enzymes into glucose and fructose, which are then absorbed into the bloodstream and used for energy. While sucrose provides a quick source of energy, excessive intake can contribute to health issues such as tooth decay, obesity, and type 2 diabetes.

Lactose is a disaccharide sugar found naturally in dairy products like milk. It is composed of two sugar molecules, glucose and galactose. Lactose is the primary carbohydrate in milk and is responsible for its slightly sweet taste. In the digestive system, lactose is broken down into its constituent sugars by an enzyme called lactase, which is produced in the small intestine. People who are lactose intolerant have low levels of lactase and may experience digestive discomfort, such as bloating, gas, and diarrhea, after consuming dairy products.

Maltose is a type of sugar, classified as a disaccharide, that consists of two glucose molecules linked together. It is commonly known as malt sugar and is found in certain grains, particularly malted barley. Maltose is created when grains start to sprout, or grow, during the early stages of their development. It is also used as a sweetener in some foods and beverages. In the body, maltose is broken down into its individual glucose molecules by digestive enzymes, allowing it to be absorbed into the bloodstream and used for energy. While maltose provides a quick source of energy, excessive intake should be avoided as it can contribute to health issues like obesity and tooth decay.

Glycogen is a type of carbohydrate that serves as a storage form of energy in animals and humans. It is made up of many glucose molecules linked together in a branching structure. Glycogen is primarily stored in the liver and muscles, where it can be broken down into glucose when energy is needed. This process, known as glycogenolysis, helps maintain stable blood sugar levels and provides a quick source of energy during periods of increased activity or when food intake is limited. Glycogen also plays a role in regulating blood sugar levels and supporting overall metabolic function.

Saturated fatty acids are a type of fat found in various foods, including animal products like meat and dairy, as well as certain plant-based oils like coconut oil and palm oil. Unlike unsaturated fats, which have double bonds in their molecular structure, saturated fats lack these bonds, making them solid at room temperature. They're commonly known as "bad fats" because high consumption has been linked to increased levels of LDL cholesterol, which is associated with heart disease and other health issues. While some saturated fats are necessary for our bodies to function, health experts generally recommend limiting intake and opting for healthier fats like those found in nuts, seeds, and avocados instead.

Unsaturated fatty acids are a type of fat found in foods like nuts, seeds, fish, and vegetable oils. Unlike saturated fats, which are solid at room temperature, unsaturated fats remain liquid. This is because they have one or more double bonds in their molecular structure. These fats are often referred to as "healthy fats" because they can help lower levels of LDL cholesterol, the "bad" cholesterol that can contribute to heart disease. Including unsaturated fats in your diet can also provide essential fatty acids that your body needs but cannot produce on its own. So, incorporating foods rich in unsaturated fats, like olive oil, avocados, and fatty fish, can be beneficial for heart health and overall well-being.

Omega-6 fatty acids are a type of polyunsaturated fat necessary for human health. They are considered "essential" because the body cannot produce them on its own and must obtain them from food. Omega-6 fatty acids play vital roles in maintaining healthy skin, supporting cell growth, and regulating metabolism. The main omega-6 fatty acid is called linoleic acid (LA), which is found in various plant-based oils such as corn oil, soybean oil, and sunflower oil. While omega-6 fatty acids are essential, excessive intake relative to omega-3s may contribute to inflammation and other health issues.

Trans fatty acids (TFAs) are a type of unsaturated fat that can be found in certain foods. They are often created during a process called hydrogenation, where liquid vegetable oils are turned into solid fats to improve texture and shelf life. They are commonly found in fried foods, baked goods, and margarine. While they can occur naturally in small amounts, most of the trans fats consumed come from processed foods. Unfortunately, research has linked high intake of trans fats to an increased risk of heart disease and other health problems.

Polyunsaturated fatty acids (PUFAs) are a type of fat with more than one unsaturated bond in their chemical structure. They are considered essential fats because the body cannot produce them on its own and must obtain them from the diet. PUFAs are divided into two main types: omega-3 and omega-6 fatty acids. These fats play crucial roles in brain function, heart health, and overall well-being. Omega-3 fatty acids, found in fatty fish, flaxseeds, and walnuts, are known for their anti-inflammatory properties and cardiovascular benefits. Omega-6 fatty acids, found in vegetable oils like soybean and corn oil, are important for skin health and cell function.

Cellulose is a type of carbohydrate, specifically a polysaccharide, that forms the structural component of plant cell walls. It is made up of long chains of glucose molecules linked together, providing strength and rigidity to plant cells. While cellulose is indigestible by humans and most animals due to their lack of enzymes capable of breaking it down, it serves as dietary fiber, aiding in digestion and promoting bowel regularity. Cellulose is found in high amounts in plant-based foods such as fruits, vegetables, whole grains, and legumes.

Oligosaccharides are a type of carbohydrate made up of a small number of sugar molecules, typically between three and ten. They are considered complex carbohydrates, but simpler than polysaccharides like starch and cellulose. Oligosaccharides can be found naturally in various foods, including beans, legumes, onions, garlic, and certain fruits and vegetables. While the human body cannot fully digest oligosaccharides, they serve as prebiotics, promoting the growth of beneficial bacteria in the gut. This can contribute to improved digestion, enhanced immune function, and overall gut health. Additionally, oligosaccharides may help regulate blood sugar levels and support weight management.

Enzymes are special proteins that speed up biological reactions in the body. They help reactions occur more quickly by reducing the amount of energy needed to start them. Enzymes are highly specific, meaning each enzyme typically activates only one type of reaction or a few closely related reactions. They play crucial roles in various bodily functions, including digestion, metabolism, and cellular processes. For example, digestive enzymes aid in breaking down food into smaller molecules that can be absorbed by the body, while metabolic enzymes assist in chemical reactions involved in energy production and the creation of essential molecules. Without enzymes, many vital biochemical reactions would happen too slowly to sustain life processes.

Chlorine is a chemical element found in nature and widely used for various purposes. It is commonly known for its role in disinfecting water to make it safe for drinking and swimming by killing harmful bacteria and other microorganisms. Chlorine is also used in the production of numerous household products such as bleach, PVC plastics, and cleaning agents. In the body, chlorine is an essential mineral that helps maintain fluid balance and pH levels, supports digestion by helping the production of stomach acid, and is involved in nerve signaling. It is primarily obtained through the diet in the form of chloride ions, which are found in table salt and many other foods.

Magnesium is an important mineral that plays several key roles in the body. It helps maintain normal muscle and nerve function, supports a steady heart rhythm, and contributes to building strong bones. Magnesium also assists in regulating blood sugar levels and blood pressure. It is involved in energy processing and protein production, making it essential for overall health. Good dietary sources of magnesium include leafy green vegetables, nuts, seeds, whole grains, and legumes.

Phosphorus is an essential mineral that plays a crucial role in various bodily functions. It is a key component of bones and teeth, providing strength and structure to skeletal tissues. Phosphorus is also involved in energy processing, helping convert food into energy for cellular activities. Additionally, phosphorus plays a role in DNA and RNA production, cell signaling, and maintaining the acid-base balance in the body. Good dietary sources of phosphorus include dairy products, meat, poultry, fish, nuts, seeds, and whole grains.

Potassium is a vital mineral that is essential for many bodily functions. It helps maintain proper fluid balance, supports healthy nerve function, and ensures normal muscle contractions, including the heartbeat. Potassium also plays a role in regulating blood pressure by counteracting the effects of sodium. Good dietary sources of potassium include fruits such as bananas, oranges, and avocados, as well as vegetables like potatoes, spinach, and tomatoes.

Sodium is an essential mineral that plays a key role in maintaining fluid balance, supporting nerve function, and ensuring proper muscle contractions. It helps regulate blood pressure and is vital for transmitting electrical signals in the nervous system. Sodium is commonly found in table salt and is naturally present in many foods, as well as added to various processed foods for flavor and preservation. While sodium is necessary for health, excessive intake can lead to high blood pressure and other cardiovascular issues.

Iodine is an essential mineral that is crucial for the production of thyroid hormones, which regulate metabolism, growth, and development. These hormones are vital for brain development, especially during pregnancy and early childhood. Iodine is naturally found in seawater and soil, and it is commonly added to table salt to ensure enough intake. Good dietary sources of iodine include seafood, dairy products, eggs, and iodized salt. Getting enough iodine is important to prevent thyroid disorders such as goiter and hypothyroidism, and to support overall metabolic health and cognitive function.

Iron is a metal found in nature that is important for health because it helps the body produce red blood cells, which carry oxygen to different parts of the body. It is especially important for energy and preventing tiredness. People get iron from foods like meat, spinach, and beans. Without enough iron, a person may feel weak or tired, and their body might not be able to function properly.

Manganese is an essential trace mineral that plays a critical role in various bodily functions. It is important for bone formation, blood clotting, and the processing of carbohydrates, proteins, and fats. Manganese also acts as an antioxidant, helping to protect cells from damage. It supports enzyme functions involved in energy production and is necessary for the proper functioning of the nervous system. Good dietary sources of manganese include whole grains, nuts, seeds, leafy green vegetables, and tea.

Molybdenum is an essential trace mineral that plays a vital role in various bodily functions. It helps activate several important enzymes involved in the processing of sulfur-containing amino acids, purines, and pyrimidines, which are components of DNA. These enzymes help in breaking down and processing proteins and other substances in the body. Molybdenum is found in a variety of foods, including legumes, nuts, dairy products, grains, and leafy vegetables. Although the body requires only small amounts of molybdenum, it is crucial for proper enzyme function and overall metabolic health.

Zinc is an essential mineral that plays an important role in many bodily functions. It supports the immune system, aids in wound healing, and is necessary for normal growth and development. Zinc is also important for the senses of taste and smell and helps with DNA and protein production. Good dietary sources of zinc include meat, shellfish, dairy products, nuts, seeds, and whole grains.

Vitamin D is an essential nutrient that plays a crucial role in maintaining bone health by helping the body absorb calcium. It also supports immune function, muscle health, and overall well-being. The body can produce vitamin D when the skin is exposed to sunlight, but it can also be obtained from foods such as fish, fortified dairy products, and egg yolks, as well as supplements. Getting enough vitamin D is important to prevent conditions like rickets in children and osteoporosis in adults, ensuring strong bones and a healthy immune system.

Vitamin C, also known as ascorbic acid, is a water-soluble vitamin that plays several important roles in the body. It is a powerful antioxidant, helping to protect cells from damage caused by harmful molecules called free radicals. Vitamin C is also essential for the growth and repair of tissues, wound healing, and the maintenance of healthy skin, blood vessels, and bones. Additionally, it supports the immune system and helps the body absorb iron from plant-based foods. Good dietary sources of vitamin C include citrus fruits, such as oranges and lemons, strawberries, kiwi, bell peppers, broccoli, and tomatoes.

Vitamin A is a fat-soluble vitamin that is essential for maintaining healthy vision, skin, and immune function. It is important for normal growth and development, reproduction, and the formation of specialized cells. Vitamin A is also a powerful antioxidant, helping to protect cells from damage caused by harmful molecules called free radicals. Good dietary sources of vitamin A include liver, fish liver oils, eggs, dairy products, and colorful fruits and vegetables, such as carrots, sweet potatoes, and spinach.

Vitamin B1, also known as thiamine, is a water-soluble vitamin that plays a crucial role in converting food into energy. It helps the body process carbohydrates, which are the main source of energy for cells. Vitamin B1 is also important for nerve function and maintaining a healthy nervous system. Good dietary sources of vitamin B1 include whole grains, fortified cereals, beans, nuts, and seeds.

Vitamin B2, also known as riboflavin, is a water-soluble vitamin that plays a crucial role in energy production and processing. It helps the body convert carbohydrates, fats, and proteins into energy that the body can use. Vitamin B2 is also important for maintaining healthy skin, eyes, and nervous system function. Good dietary sources of vitamin B2 include dairy products, lean meats, poultry, fish, eggs, fortified cereals, and leafy green vegetables.

Vitamin B12, also known as cobalamin, is a water-soluble vitamin that plays a crucial role in many bodily functions. It is important for the production of red blood cells, which carry oxygen throughout the body, and for maintaining healthy nerve cells. Vitamin B12 is also involved in DNA production and supports normal brain function. Good dietary sources of vitamin B12 include meat, fish, poultry, eggs, dairy products, and fortified cereals. However, vitamin B12 is primarily found in animal products, so vegetarians and vegans may need to supplement their diet to ensure enough intake.

Vitamin E is a fat-soluble vitamin and antioxidant that plays a vital role in protecting cells from damage caused by harmful molecules called free radicals. It helps maintain healthy skin, eyes, and immune function, and it also supports the proper functioning of blood vessels and heart health. Vitamin E is found in various foods, including nuts, seeds, vegetable oils, such as sunflower, safflower, and wheat germ oil, green leafy vegetables, and fortified cereals.

Vitamin K is a fat-soluble vitamin that plays a crucial role in blood clotting and bone health. It helps the blood to clot properly, which is important for wound healing and preventing excessive bleeding. Additionally, vitamin K is involved in bone metabolism and helps maintain strong and healthy bones. Good dietary sources of vitamin K include green leafy vegetables, such as spinach, kale, and broccoli, Brussels sprouts, cabbage, fish, meat, eggs, and dairy products.

Albumin is a protein found in the blood that is produced by the liver and plays several important roles in the body. It helps manage blood volume by maintaining the balance of fluids between the blood vessels and tissues. Albumin also acts as a carrier protein, transporting various substances such as hormones, fatty acids, and medications throughout the body. Additionally, it helps in maintaining proper pH levels in the blood and to lessen changes in acidity. Low levels of albumin can suggest liver or kidney diseases, malnutrition, or other health conditions, while high levels may be seen in dehydration or certain inflammatory diseases.

Ascorbic acid, commonly known as vitamin C, is a water-soluble vitamin found in various fruits and vegetables. It is essential for maintaining overall health and plays several important roles in the body. As an antioxidant, ascorbic acid helps protect cells from damage caused by harmful molecules called free radicals. It is also necessary for the production of collagen, a protein that supports the structure of skin, bones, and blood vessels. Additionally, ascorbic acid boosts the immune system, aids in wound healing, and enhances the absorption of iron from plant-based foods. Good dietary sources of ascorbic acid include citrus fruits, such as oranges, lemons, and grapefruits, strawberries, kiwi, bell peppers, broccoli, and tomatoes.

An emulsifier is a unique substance that possesses the ability to create and maintain stable mixtures of immiscible liquids. Their primary function is to facilitate the dispersion and stabilization of oil and water-based components. They work by forming a protective layer around tiny droplets of one liquid within the other, preventing separation and maintaining a homogeneous blend. Emulsifiers can be derived from natural or synthetic sources and are commonly used in food and cosmetic products. Emulsifiers play a crucial role in a wide range of applications, from salad dressings and mayonnaise to lotions and creams, enabling the combination of ingredients that would otherwise remain separate.

Folic acid, also known as folate or vitamin B9, is a water-soluble vitamin that plays a crucial role in cell division and DNA synthesis. It is especially important during periods of rapid cell growth and development, such as pregnancy and infancy. Folic acid is essential for the formation of red blood cells and the prevention of serious birth defects in an infant's brain and spine. It also supports the processing of amino acids and the production of certain neurotransmitters. Good dietary sources of folic acid include leafy green vegetables, citrus fruits, beans, lentils, fortified grains, and supplements.

Gluten is a protein found in wheat, barley, rye, and foods made from them. It gives dough its elasticity and helps it rise during baking. While gluten is harmless for most people, those with celiac disease or gluten sensitivity may experience negative reactions when consuming gluten-containing foods. In these individuals, gluten can damage the lining of the small intestine, leading to symptoms such as abdominal pain, bloating, diarrhea, and fatigue.

Niacin, also known as vitamin B3, is a water-soluble vitamin that plays an important role in converting food into energy. It helps maintain healthy skin, nerves, and digestion. Niacin is also involved in the proper functioning of enzymes and helps improve circulation and cholesterol levels. Good dietary sources of niacin include meat, fish, poultry, whole grains, nuts, seeds, and legumes.

Tannin is a naturally occurring compound found in various plants, particularly in the bark, leaves, and fruit skins. It is most commonly associated with tea, wine, and certain fruits like grapes, apples, and berries. Tannins have a bitter and drying taste, which can make the mouth feel dry. They play a role in protecting plants from pests and harmful microorganisms. In addition to their natural protective functions, tannins are used in the leather tanning industry to process animal hides and in the production of some inks and dyes. In the diet, moderate consumption of tannin-rich foods and drinks can offer antioxidant benefits, though excessive intake can interfere with nutrient absorption.

Vitamin B6, also known as pyridoxine, is a water-soluble vitamin that plays an essential role in many bodily functions. It helps convert food into energy, supports brain health, and aids in the production of neurotransmitters, which are chemicals that transmit signals in the brain. Vitamin B6 is also important for the production of red blood cells and helps maintain normal levels of homocysteine, an amino acid associated with heart health. Good dietary sources of vitamin B6 include poultry, fish, potatoes, chickpeas, bananas, and fortified cereals.

Biotin, also known as vitamin B7 and vitamin H, is a water-soluble vitamin that plays a key role in the processing of fats, carbohydrates, and proteins. It helps the body convert these nutrients into energy and is essential for maintaining healthy hair, skin, and nails. Biotin also supports the health of the nervous system and helps in the production of certain enzymes. Good dietary sources of biotin include eggs, nuts, seeds, fish, meat, dairy products, and certain vegetables like sweet potatoes and spinach.

Pantothenic acid, also known as vitamin B5, is a water-soluble vitamin that is essential for converting food into energy. It plays a key role in the production of coenzyme A, which is vital for various metabolic processes, including the breakdown of carbohydrates, fats, and proteins. Pantothenic acid also helps in the production of red blood cells and certain hormones. Good dietary sources of pantothenic acid include meat, fish, poultry, whole grains, dairy products, eggs, legumes, and vegetables like broccoli and avocados.