School Project: A Comprehensive Study on Lactose Intolerance

Subject: Biology / Home Science / Health Education

Class: XII

Topic: Lactose Intolerance - Understanding the "Dairy Dilemma"

1. Acknowledgment

I would like to express my sincere gratitude to my teacher, [Teacher's Name], for their
guidance, support, and valuable insights throughout the preparation of this project. Their
expertise has been instrumental in helping me understand the complex biological and dietary
aspects of lactose intolerance. I would also like to thank my parents for their encouragement
and support.

2. Introduction

Lactose intolerance is a common digestive disorder that affects a significant portion of the
global population. It is often confused with a milk allergy, but it is fundamentally different.
This project aims to explore the biological basis, symptoms, diagnosis, and management of
lactose intolerance. By understanding this condition, we can appreciate the importance of
personalized nutrition and the role of enzymes in our digestive system.

3. What is Lactose?

Lactose is a type of sugar (a disaccharide) that is naturally found in milk and dairy products.
It is made up of two smaller sugar units: glucose and galactose. For the body to use lactose
as an energy source, it must be broken down into these two simpler sugars. This breakdown
process is carried out by a specific enzyme.

4. The Role of the Enzyme Lactase

The key to digesting lactose lies in the enzyme lactase. Lactase is produced in the cells lining
the small intestine. Its primary function is to break down the bond between glucose and
galactose in lactose.

 Normal Digestion: When a person with sufficient lactase consumes milk, the enzyme
breaks down lactose into glucose and galactose in the small intestine. These simpler
sugars are then absorbed into the bloodstream and used for energy.
  Lactose Intolerance: In individuals with lactose intolerance, the body produces very
little or no lactase. As a result, when they consume milk or dairy products, the lactose
remains undigested and travels to the large intestine.

5. Types of Lactose Intolerance

Lactose intolerance is not a "one-size-fits-all" condition. There are several types:

 Primary Lactose Intolerance: This is the most common type. As a person ages, their
body naturally produces less lactase. This is a normal and genetically programmed
process. It is more prevalent in people of East Asian, African, and Hispanic descent.
 Secondary Lactose Intolerance: This type occurs when the small intestine is
damaged due to a disease, injury, or surgery. The damage reduces the production of
lactase. Causes can include celiac disease, Crohn's disease, or a severe stomach flu.
Once the underlying condition is treated, the lactase production may return to normal.
 Congenital Lactose Intolerance: This is an extremely rare genetic disorder where a
baby is born with an inability to produce any lactase. It is a serious condition that
requires a strict lactose-free diet from birth.
 Developmental Lactose Intolerance: This type is seen in some premature babies.
Their digestive system is not yet fully developed, and they may not produce enough
lactase. This condition usually resolves on its own as the infant matures.

6. Symptoms of Lactose Intolerance

The symptoms of lactose intolerance are a direct result of undigested lactose fermenting in
the large intestine. The severity of symptoms depends on the amount of lactose consumed
and the individual's degree of lactase deficiency.

 Common Symptoms:
o Bloating
o Abdominal pain or cramps
o Gas
o Diarrhea
o Nausea
 Timeline: Symptoms typically appear within 30 minutes to two hours after
consuming dairy products.

7. Diagnosis

A doctor can diagnose lactose intolerance through a combination of a physical examination,

patient history, and specific tests:

 Hydrogen Breath Test: This is the most common test. The patient drinks a lactose-
rich liquid. If lactose is not digested, bacteria in the large intestine will ferment it,
 producing hydrogen gas. This gas is absorbed into the bloodstream and exhaled, and
its level can be measured in the breath. A significant increase in hydrogen indicates
lactose intolerance.
 Lactose Tolerance Test: The patient drinks a lactose solution, and blood sugar levels
are measured before and after. If the blood sugar level does not rise, it indicates that
the lactose was not broken down and absorbed.
 Genetic Testing: Can be used to identify the genetic predisposition for primary
lactose intolerance.

8. Dietary Management

Lactose intolerance is managed primarily through dietary changes. The goal is not always to
eliminate all dairy but to find a level of intake that does not cause symptoms.

 Dietary Adjustments:
o Reduce or Avoid High-Lactose Foods: This includes milk, ice cream, and
soft cheeses.
o Choose Low-Lactose or Lactose-Free Products: Many supermarkets now
offer a wide range of lactose-free milk, yogurt, and cheese.
o Use Lactase Enzyme Supplements: These are over-the-counter tablets or
drops that can be taken before a meal to help the body break down lactose.
o Fermented Dairy Products: Many people with lactose intolerance can
tolerate small amounts of fermented dairy products like yogurt and hard
cheeses (e.g., cheddar, Swiss) because the fermentation process reduces the
lactose content.
 Important Nutritional Consideration: Milk and dairy products are an important
source of calcium and vitamin D. Individuals who eliminate dairy must ensure they
get these nutrients from other sources, such as:
o Calcium: Fortified orange juice, green leafy vegetables (kale, spinach),
fortified cereals, and canned salmon.
o Vitamin D: Fortified plant-based milks (soy, almond), fortified cereals, and
exposure to sunlight.

9. Conclusion

Lactose intolerance is a manageable condition, not an allergy. It is caused by a deficiency of

the lactase enzyme and results in uncomfortable digestive symptoms. By understanding its
biological basis and implementing simple dietary and lifestyle changes, individuals can
effectively manage their symptoms and continue to live a healthy and balanced life. This
project highlights the fascinating relationship between our genes, enzymes, and the food we
eat, and how a small biological difference can have a significant impact on our daily lives.

10. Bibliography
  NCERT Biology Textbook for Class 12
 Medical websites (e.g., Mayo Clinic, NIH)
 Scientific Journals (e.g., Journal of Nutrition)
 Books on Human Anatomy and Physiology

Note to the student:

 Add your name, class, and roll number to the cover page.
 Include relevant diagrams, such as a diagram of the small intestine showing lactase
action, or a chart showing the lactose content of various foods.
 You can also include a sample diet plan for a person with lactose intolerance to make
the project more practical and visually appealing.
 Consider adding a section on the difference between lactose intolerance and milk
allergy for clarity.