Nutrients And Their Importance For Human Body

Nutrients are components that are essential to life and health providing the body with energy and components of repair and life support. The varieties of enriched components of nutrients can include proteins, vitamins, fats, minerals, and carbohydrates.

Just like every other component in our body, not all the nutrients provide energy but are necessary for many other functions. Hence based on this, nutrients are divided into two broad categories; Macronutrients which are required by our body in large amounts, and micronutrients which are required by our body in small amounts.

The consumption of dietary nutrients applies to animals, plants, fungi, and protists. They are incorporated into cells for metabolic purposes or excreted by these cells to create other essential components such as hairs, scales, feathers, or exoskeletons.

Some nutrients are metabolically converted into smaller molecules in the process of releasing energy, such as carbohydrates, lipids, proteins, and fermentation products which can be ethanol or vinegar followed by end products of water and carbon dioxide.

Essential nutrients for animals are the energy sources, some of the amino acids that are combined to create proteins, a subset of fatty acids, vitamins, and certain minerals. Plants require more diverse minerals absorbed through roots, plus carbon dioxide and oxygen absorbed through leaves. Fungi live on dead or living organic matter and meet nutrient needs from their host.


These are required by the human body in large amounts. It provides energy to a living beings for the function of the metabolic system. These contribute hugely to the conversion of energy processes. Macronutrients include fats, proteins, and carbohydrates.

1. Carbohydrates

Being an essential macronutrient that is required by the body, it is made up of elements like Carbon, Oxygen, and Hydrogen. It also provides sufficient energy for the central nervous system and working muscles. They also prevent protein from being used as an energy source and enable fat metabolism thereby.

It supports brain function and influence, mood, memory, etc. Carbohydrates are classified based on their complexity and structure. Based on this, they could be Simple carbohydrates, which contain just one or two sugars such as fructose and galactose. These single sugars are called monosaccharides and carbs with two sugars such as lactose and maltose and referred to as disaccharides. 

Monosaccharide carbohydrates cannot be hydrolyzed further to give simpler units of polyhydroxy aldehyde or ketone. If a monosaccharide contains an aldehyde group, then it is called aldose and on the other hand, if it contains a keto group then it is called a ketose.

On hydrolysis, disaccharides yield two molecules of either the same or different monosaccharides. The two monosaccharide units are joined by oxide linkage which is formed by the loss of water molecules and this linkage is called glycosidic linkage. Sucrose is one of the most common disaccharides which on hydrolysis gives glucose and fructose. Maltose and Lactose are the other two important disaccharides.

Complex carbohydrates are referred to as polysaccharides and they contain more than two sugar molecules. It is a polymer of α-glucose and consists of two components i.e., Amylose and Amylopectin. Cellulose is also one of the polysaccharides that are mostly found in plants. They are usually found in high starchy foods.

In the perspective of diet and bodily requirement these simple and complex carbs can briefly be classified into three types;

Sugars: They come under simple carbohydrates as they appear in the most basic form of carbs. They can be added to foods such as sugar in candy, processed foods, and desserts. Naturally, they are found in fruits, vegetables, and milk.

Starches: They come under complex carbohydrates and are made up of huge amounts of sugars strung together in a chain making a complex carb molecule. Starch breaks down inside the human body once consumed during metabolism to use as energy. They are found in abundance in bread, cereal, pasta, and a few vegetables like potatoes.

Fiber: Being another complex carb, fibers are super healthy as it takes a lot of time for the human body to break it down, and hence once a person consumes it, they feel full and prevent the person from overeating. They also have additional benefits such as it prevents stomach and intestinal issues, preventing cholesterol and blood sugar, and also helping in the absorption of enough water into the body.

The process of the breaking down of carbohydrates into simple energy absorbing units is carbohydrate metabolism and it is a series of biochemical processes. Good carbohydrates are found in healthy whole grains such as whole-wheat bread, rye, barley, and quinoa.

Fruits, beans, whole grains, vegetables, and leafy vegetables are rich in good and healthy carbohydrates, which are an essential source of proteins, minerals, and phytonutrients as well. Unhealthy sources of carbohydrates include white bread, pastries, desserts like pies, sodas, and other highly processed refined foods.

These contain easily digested carbohydrates that may contribute to weight gain, diabetes, and heart diseases. The wrong form of carbohydrates is usually obtained via these unprocessed foods and items like creams and sodas. Carbohydrates account for half of the healthy human body.

2. Proteins

They are large complex molecules that are made up of hundreds or thousands of smaller units of amino acids which are attached forming long chains. These large macromolecules perform a vast array of functions within organisms, including catalyzing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another.

Proteins play an important role in the growth and maintenance of the human body. It breaks down the amino acid constituent and uses it efficiently when one falls ill or during the time of breastfeeding etc. Enzymes may also function outside the cell, such as digestive enzymes like lactase and sucrase, which help digest sugar.

Bodily functions that depend on enzymes include digestion, energy production, blood clotting, and muscle contraction. Some proteins are hormones which are chemical messengers that aid communication between the body cells, tissues, and organs. They’re made and secreted by endocrine tissues or glands and then transported in the blood to their target tissues or organs where they bind to protein receptors on the cell surface.

The fibrous proteins provide cells with shape, structure, and rigidity. Most microorganisms and plants can biosynthesize all 20 standard amino acids, while animals (including humans) must obtain some of the amino acids from the diet. 

It is suggested that an adult human must consume 0.8g of protein concerning their body weight, with an extra 10 or 15g recommended for pregnant and lactating women. Requirements are higher for growing children and lactating women. Certain plant-based foods such as legumes like beans, peas, and lentils do contain a considerable amount of proteins.

However, most legumes tend to be deficient in methionine. Certain cereals contain protein-rich substances however are low in lysine and tryptophan content. Thus, the combination of different plant-based foods in dishes such as rice and beans, or peanut butter and bread, results in a complementary effect that raises the protein quality when compared with either of these food types consumed alone.

Therefore, adults can obtain adequate amounts of high-quality protein from a vegetarian or vegan diet. It should be noted, however, that taurine may be required for neonates, and that taurine is only present in animal-based foodstuffs. 

The proteins or the amino acids required by organisms can be of three groups; i.e., Essential amino acids, Non-Essential amino acids and Conditional amino acids.

  • Essential amino acids include those that cannot be made by the body and must be supplied by food. They do not be eaten completely within one meal. The balance of these over a whole day is important.
  • Non-essential amino acids are made by the body from the essential amino acids or in the normal breakdown of proteins.
  • Conditional amino acids are already stored in the body via various amounts of nutrition and are used when the body undergoes any illness and any form of stress. The effects of protein deficiency and malnutrition range in severity from growth failure and loss of muscle mass to decreased immunity, weakening of the heart and respiratory system, and death.

3. Fats

Ester components, fatty acids, or a mixture of both is referred to as fat in human nutrition. The term fat is often referred to the triglyceride groups, the abundant component in vegetable oil and fatty tissues. Being a very essential macronutrient it holds an important place in the human diet in milk, butter, salt pork, and cooking oils.

They are a major and dense source of food energy for many animals and play important structural and metabolic functions in most living beings, including energy storage, waterproofing, and thermal insulation. The human body can produce the fat it requires from other food ingredients, except for a few essential fatty acids that must be included in the diet.

Dietary fats are also the carriers of some flavor and aroma ingredients and vitamins. Each gram of fat when metabolized produces around nine food calories which are approximately 37 KJ.

Fats play a vital role in maintaining healthy skin and hair, insulating body organs against shock, maintaining body temperature, and promoting healthy cell function. Fat also serves as a useful buffer against a host of diseases.

When a particular substance, whether chemical or biotic, reaches unsafe levels in the bloodstream, the body can effectively dilute or at least maintain the equilibrium of the offending substances by storing it in new fat tissue.

There are two essential fatty acids (EFAs) in human nutrition ie., alpha-linolenic fatty acid and linoleic fatty acid. Other lipids needed by the body can be synthesized from these and other fats.


These are nutrients required in a very small amount for the body. They build and repair damaged tissues along with metabolism. They include calcium, iron, vitamins, and minerals.

1. Calcium

They come under the huge category of minerals and are vital in building strong bones and teeth. It is also required by our nerves, muscles, and heart for proper functioning. The main sources of calcium in the diet include pudding, milk, yogurt, tofu, canned fish, leafy green vegetables, etc.

Lack of calcium can lead to osteoporosis, a condition in which the skeletal system is characterized by low bone mass, disorientation, and disfigurations.

2. Iron

It is abundant in red blood cells and helps in the transportation of oxygen across the body via hemoglobin. It is obtained through food sources such as spinach, soybeans, iron-rich fruits like dates and beetroot.

3. Minerals, Vitamins & Salt

Most of the essential vitamins are obtained through water which is advised to be consumed daily in an amount of around 2-4 liters. Eating a variety of healthful foods can provide a body with different vitamins. Some of these such as vitamin C is also an antioxidant. They help protect cells from damage by removing toxic molecules known as free radicals from the body.

Vitamins can be of different types such as vitamin A, C, D, E, K, B1, B2, and B3. They can be water-soluble and fat-soluble. Water-soluble vitamins should be consumed regularly as they cannot be stored easily after their quick washing out.

The body absorbs fat-soluble vitamins through the intestines with the help of fats (lipids). The body can store them and does not remove them quickly. People who follow a low-fat diet may not be able to absorb enough of these vitamins. If too many build up, problems can arise.

An inadequate amount of a nutrient is a deficiency. Deficiencies can be due to several causes including an inadequacy in nutrient intake, called a dietary deficiency, or any of several conditions that interfere with the utilization of a nutrient within an organism.

Some of the conditions that can interfere with nutrient utilization include problems with nutrient absorption, substances that cause a greater than normal need for a nutrient, conditions that cause nutrient destruction, and conditions that cause greater nutrient excretion. Nutrient toxicity occurs when excess consumption of a nutrient harms organisms.

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