Nutrition in Human Beings: Key Nutrients and Their Roles

Nutrients can be defined as the substances in food that maintain the body and make it work.  Most of what one eats is formed of carbohydrates, proteins, and fats.  Some of the vital nutrients that could be taken in smaller amounts are vitamins and minerals along with fibre and water.  Such a diet is called a balanced diet. 

Nutrition in Human Beings

Following are the major nutrients required by the human body:

• Carbohydrates

Complex carbohydrates, particularly starch, are found in foods such as pasta, bread, rice potatoes, and cereals.  During digestion, starch is broken down to the simple sugar glucose, the body’s main source of energy.

• Vitamins and Minerals

Vitamins and Minerals are required in minute amounts and are essential for maintaining a strong immunity, building strong bones and muscles and also promotes normal growth and development.  Most vitamins come from fresh fruit and vegetables, with some also found in fish, meat, dairy, and eggs.  Minerals, like calcium and iron, also help the body perform optimally.  The best sources are vegetables, dairy, meat, and some fish.

• Fats

Some fat supplying food are - Dairy food, meat, seeds, and nuts as do vegetable oils.  Fat is digested into fatty acids, which are used as an energy source and to form cell membranes.  Or they’re rebuilt into fat that, under the skin, insulates the body and helps to make and keep us warm.

• Proteins

A rich source of protein is fish along with lean meat, poultry, and beans.  After digestion into the body, proteins supply the body with amino acids.  These building blocks are reassembled by cells into different proteins used for construction such as enzymes, and a myriad of other roles. 

• Water

Around 50 – 70 per cent of our body is made of water. Therefore this amount should always be present in the human body. It is the only source via which all the important nutrients, vitamins, minerals and other wastes in the body are transported. Water also plays a vital role in regulating the body’s temperature.

Human Digestive System

Digestion has been an important procedure performed by the human body which provides energy by breaking down the massive food molecules into easily absorbable molecules to supply energy for various life processes. The complete process of digestion happens through a stepwise process which is common to all living organisms. Digestion includes the following processes-

1. Ingestion: It is the process human beings follow of ingesting the food by actually eating it. In the mouth the food material is subject to cutting, tearing, chewing, and a little bit of pre-digestion using the salivary juice and eventually swallowing it.

2. Digestion: It’s the breakdown of the ingested food into microscopic and finally molecular fragments. Most of the digestion happens in the stomach and a small part of it also occurs in the small intestine.

3. Absorption: This is often a critical stage in which the nutrients are taken up from digestive organs and distributed to the body’s tissues. This process is where food swallowed is converted to actual energy to be used in human bodies.

4. Excretion: This is the last process where waste material is excreted from our bodies.

Why is Nutrition in Human Beings important? 

Nutrition in human beings is vital because of the three main reasons - 

• Undernutrition includes problems like low weight, small height and low weight as per the age.  

• Can also cause Micronutrient-related malnutrition, which includes micronutrient deficiencies or insufficiencies.  

• Issue of being overweight, obese and diet-related noncommunicable diseases (such as heart disease, stroke, diabetes and some cancers).

Poor Nutrition

Malnutrition which can also be referred to as poor nutrition is a condition where a person's body is supplied with the right balance of all nutrients required for optimal health. It is the deficiency or over-consumption of certain nutrients that have led to a suboptimal diet. Simply put, it is the imbalance of intake of energy via nutrients in a person. This could be because of a bad lifestyle, but also factors like food security and other such socioeconomic and political factors. 

Poor nutrition or malnutrition refers to getting too little or too much of the nutrients for your body due to under-eating or over-eating either because of unfortunate circumstances like poverty, war and mass starvation or utterly out of negligence and bad eating habits like an unbalanced diet.

Following Are the Types of Malnutrition or Poor Nutrition:

• Undernutrition - This is a condition that arises due to a lack of proteins, calories and micronutrients in one's diet due to an acute deficiency of food intake. It can range from being a mild concern to adverse effects. The mild concern is when the Body Mass Index (BMI) is just slightly off the mark in thin adults for their corresponding apt weight and height. But adverse effects could be because of chronic deprivation of nutrients, which is directly associated with poor health, lack of energy for physical tasks and death as well.

• Stunting - This is a cause of concern in children who are chronically deficient in nutrients that are needed for the optimal 'height-for-age' nutritional index. In stunting, the height of the child is drastically lesser for his or her age. The impacts of this condition are poor performance in school, late development of motor skills and impaired brain function.

• Wasting - In this condition, the 'weight-for-height' nutritional index can be used to determine the nutritional status of children. In this condition, the children are at risk of dying due to being too thin for their height due to starvation or disease.

• Micronutrient Deficiencies - This is a condition that arises due to a lack of proper intake, absorption or use of essential micronutrients like vitamins and minerals that are required by a person for body growth and intellectual performance. Iron, iodine, zinc, vitamin A, vitamin B12 and folate are one of the most deficient micronutrients in peoples' diets across the world.

• Obesity - Being extremely overweight for their height and age is detrimental to good health. Obesity is considered a disease due to abnormal fat accumulation in a person's body. It is the excessive amount of body fat in a person's body compared to acceptable levels determined by the optimal Body Mass Index (BMI). Studies have shown obesity is directly linked to deadly conditions like coronary diseases, stroke, diabetes and particular types of cancers.

Nutrition Tips for a Balanced Diet

The following are some nutrition tips for a balanced diet:

• Avoid food items that have unhealthy fat not needed by your body. These food items include dark meat, whole milk, butter, cheese, poultry skin and so on. You can replace dark meat or fatty meat with fish. Or at least remove the skin of the chicken before cooking. You should try and avoid fried meat, instead grill or broil it. These tips will help you avoid bad cholesterol and coronary risks. Plant oils and nuts are considered good fats in your diet.

• Staying hydrated is important, but aerated drinks like cola are not the answer. Sweetened drinks like packaged juices, iced tea and milkshakes should also be avoided as they contain an unbelievable amount of sugar and calories that are in excess of your body requirements. Consuming processed foods and sugary drinks are linked to insomnia, which is a condition of sleeplessness. Foods rich in melatonin and serotonin like walnuts, bananas are considered helpful to prevent insomnia. 

• Drink a good amount of water in a day.

• Calcium and Vitamin D are needed by the body for good bone health and speedy recovery from injuries like fractures. But whole milk may not be the way to go. Unsweetened soy milk or almond milk, oranges, broccoli, kale, figs, blackberries and apricots are rich in these nutrients crucial towards good health.

• Eat plenty of fruits and vegetables in a day with your meals or as snacks. 

• Do not consume alcoholic beverages, saturated fats, preservatives and chemical additives in your diet.

• Limit the use of salt in your cooking as it can lead to high blood pressure.

• High fibre food items like brown rice, whole grains and fruits and vegetables with their skin should be included in meals.

• Almonds, shellfish like mussels, oysters and scallops, quinoa, flaxseed products, chia seed, walnuts and kidney beans are rich in multiple vitamins and minerals crucial to your diet towards efficient working of all your body systems. 

Students can learn more about the working of the human body in biology lessons available on Vedantu. Study material on various systems like the digestive system, nervous system and so on that keep the human body in working condition are available for free download on the Vedantu website and app