Malnutrition: Causes of Over-nutrition and Under-nutrition & Most Affected Regions

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  • 0:05 What Is Malnutrition?
  • 1:23 Under-Nutrition
  • 2:58 Prevalence of Under-Nutrition
  • 4:20 Over-Nutrition
  • 5:09 Prevalence of Over-Nutrition
  • 6:05 Lesson Summary
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Lesson Transcript
Instructor: Margaret Cunningham

Margaret has taught many Biology and Environmental Science courses and has Master's degrees in Environmental Science and Education.

Have you ever thought about your diet and whether or not you are getting the appropriate nutrients you need to remain healthy? In this lesson, we will describe the concept of malnutrition and explore the ways that people's diets can be unbalanced. We will also discuss regions of the world where malnutrition is prevalent and why.

What is Malnutrition?

Think back on everything you have eaten over the last 24 hours. Do you think that your diet is well balanced and that you are getting the appropriate nutrients you need? Proper nutrition is very important to maintaining a healthy body and mind. The body requires over 40 essential nutrients to function properly, including vitamins, minerals, amino acids, protein and carbohydrates.

In addition to the quality of nutrients consumed, the body must also maintain a certain quantity of food to remain healthy. Humans must consume a certain amount of calories each day in order to maintain a productive and energetic lifestyle.

A large problem facing the human population today is malnutrition. Malnutrition is when a person's diet has an imbalance of the essential nutrients that the body needs to remain healthy. This imbalance in nutrients can weaken the person's immune system and body and make them more susceptible to illnesses. Malnutrition can also cause delays in a child's physical and mental development.

Malnutrition is often divided into two different types, which are under-nutrition and over-nutrition. These two different types of malnutrition vary by what the person is consuming, how it is influencing their body and the prevalence in certain regions of the world.


When most people think of malnutrition, they often think of someone who is suffering from under-nutrition. Under-nutrition occurs when a person consumes a diet that does not meet the necessary requirements for the amount of essential nutrients or calories a person needs to remain healthy.

This type of malnutrition can occur when people are not eating enough food, or when the food they are eating does not contain well-balanced nutrients. The World Health Organization estimates that one out of every three people is suffering from a deficiency in one or more essential nutrients.

The symptoms associated with under-nutrition vary by deficiency, but all deficiencies will eventually cause permanent harm to the body. Throughout the world, there are three common deficiencies that people suffer from. Lack of vitamin A in the diet is a very large problem worldwide and results in many cases of blindness in children each year. A deficiency in iron can cause a person to become anemic, which can result in fatigue, increased risk of infection and increased risk of hemorrhaging during childbirth.

Iodine deficiency is also very common, with one-third of the human population suffering from a lack of iodine. Iodine is important for proper functioning of the thyroid gland, which is responsible for producing hormones that manage the body's metabolic rate. A lack of iodine can cause stunted growth, mental delays and the creation of goiters, which are when the thyroid glands at the base of the neck become swollen.

Prevalence of Under-Nutrition

Under-nutrition is most common in low-income, developing countries and is prevalent in sub-Saharan Africa and Southern Asia, where access to a well-balanced diet is very limited. More specifically, almost two-thirds of the people that suffer from under-nutrition live in only seven countries, which include India, Bangladesh, Ethiopia, Indonesia, China, Pakistan and the Democratic Republic of Congo. Most people in these poor countries survive on diets that include low amounts of protein, high amounts of carbohydrates and are mainly vegetarian, with wheat, rice and corn as large staples in the diet.

In many low-income, developing countries, people do not have access to well-balanced diets because of variations in local climate, political issues and increases in population. Specifically in sub-Saharan Africa, the climate is extreme and has limited rainfall, which reduces the amount of food that can be produced.

Political unrest can also lead to under-nutrition when it results in food not being distributed equally to people of all social groups. Low-income, developing countries also suffer from dramatic increases in the human population, which can lead to less food available per person.


Although over ten percent of the world is suffering from a lack of proper nutrition, there are some areas on Earth where food is plentiful, but people still exhibit a type of malnutrition. Over-nutrition occurs when a person consumes a diet that exceeds the necessary requirements for the amount of essential nutrients, or the amount of calories a person needs to remain healthy.

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