Lactose Intolerance: Causes, Symptoms, Diagnosis, Treatment, and Complete Diet Plan

Health Desk
Sandeep Dhand
Nutritionist And Health Educator

Introduction

Lactose intolerance is one of the most common digestive problems in the world. Millions of people experience difficulty in digesting milk or dairy products. In simple words, lactose intolerance means “the body cannot digest milk properly.”

This happens because the body does not produce enough lactase, an enzyme that breaks down lactose (milk sugar). When lactase is low, lactose remains undigested and causes digestive discomfort such as gas, bloating, cramps, and sometimes diarrhea.

Lactose intolerance is not a disease that damages the body permanently. It is a manageable condition, and with the right diet, lifestyle, and knowledge, a person can live a completely healthy life. Many people mistakenly think that they must completely stop dairy, but that is not always true. It depends on the severity.

This article explains lactose intolerance in simple and clear language, covering its causes, symptoms, types, diagnosis, treatment, complications, and a complete diet plan for both vegetarians and non-vegetarians.

Understanding Lactose and Lactase

What is Lactose?

Lactose is a natural sugar present in milk and all dairy products. It is found in:

Cow milk

Buffalo milk

Goat milk

Cheese

Butter

Cream

Ice-cream

Yogurt

Milk sweets (kheer, rabri, kulfi, etc.)

What is Lactase?

Lactase is an enzyme produced in the small intestine.
Its main job is to break down lactose into two smaller sugars—glucose and galactose—so the body can absorb them easily.

When the body does not produce enough lactase, lactose remains undigested, leading to discomfort. This condition is called lactase deficiency or lactose intolerance.

Why Does Lactase Decrease? (Causes)

There are several reasons why the body stops making enough lactase:

1. Genetic Factors

This is the most common cause. In many families, adults naturally produce less lactase as they grow older. This is called primary lactose intolerance.

2. Aging

Children produce high amounts of lactase, but as people reach adulthood, lactase levels naturally drop.

3. Intestinal Diseases

Some diseases damage the intestines and reduce lactase production:

Celiac disease

Crohn’s disease

Ulcerative colitis

Gastroenteritis

Severe diarrheal infections

This type is known as secondary lactose intolerance.

4. After Surgery or Injury

If someone has undergone intestinal surgery, lactase production may reduce.

5. Premature Birth

Premature babies may have temporary lactose intolerance because their intestines are not fully developed.

6. Some Medications

Long-term antibiotics or treatments that affect gut health may reduce lactase.

Types of Lactose Intolerance

Understanding the types helps plan treatment better.

1. Primary Lactose Intolerance

Most common

Genetic

Starts slowly after childhood

Permanent but manageable with diet

2. Secondary Lactose Intolerance

Caused by intestinal disease, infection, or injury

Usually temporary

Lactase returns to normal after the intestine heals

3. Congenital Lactase Deficiency

Very rare

Babies are born with almost no lactase

Must avoid lactose completely from birth

4. Developmental Lactose Intolerance

Seen in premature babies

Usually improves as the baby grows

Symptoms of Lactose Intolerance

Symptoms usually appear 30 minutes to 2 hours after consuming dairy products.

Common Symptoms:

Bloating

Gas

Abdominal cramps

Diarrhea

Rumbling stomach

Nausea or vomiting

Heavy feeling in the stomach

Pain around the navel area

Less Common Symptoms:

Headache

Fatigue

Bad breath

Constipation (in some people)

Dehydration due to frequent loose stools

Symptoms vary from person to person. Some people can tolerate small amounts of dairy, while others cannot tolerate even a little.

How is Lactose Intolerance Diagnosed?

A doctor uses several tests to confirm lactose intolerance.

1. Lactose Tolerance Test

The patient drinks a lactose-rich liquid. Blood sugar is tested after 2 hours. If glucose levels do not rise, it means the body failed to digest lactose.

2. Hydrogen Breath Test

This is the most accurate test. Undigested lactose produces extra hydrogen in the breath.

3. Stool Acidity Test

Used for infants. Undigested lactose increases the acidity of stool.

4. Elimination Diet

The simplest method:
Stop all dairy for 2 weeks → Symptoms reduce → Reintroduce dairy → Symptoms return.

Complications of Lactose Intolerance

If not managed properly, lactose intolerance may lead to:

1. Calcium Deficiency

Because dairy is the biggest source of calcium.

2. Bone Problems

Osteopenia

Osteoporosis

Weak bones

Muscle cramps

3. Vitamin D Deficiency

Milk is also a major source of Vitamin D.

4. Malnutrition

Especially in children.

5. Dehydration

Due to diarrhea.

These complications are avoidable with the right diet plan and lifestyle.

Treatment and Management

There is no permanent cure, but lactose intolerance can be fully controlled.

1. Adjust Dairy Intake

Some people tolerate:

½ cup milk

Hard cheese

Yogurt

Buttermilk

Test your tolerance level.

2. Lactase Supplements

Tablets or drops taken before food help digest lactose.
Available as Lactaid, Laczyme, etc.

3. Consume Lactose-Free Milk

Supermarkets offer milk with pre-broken lactose.

4. Probiotics

Improve gut health and help digestion (curd, probiotic drinks, capsules).

5. Treat Underlying Conditions

If secondary lactose intolerance is due to infection or celiac disease, treat that first.

6. Eat Calcium and Vitamin D-Rich Foods

To prevent bone problems.

Detailed Diet Plan for Lactose Intolerance

This is the most important section.
Here is a complete simple diet plan for both vegetarian and non-vegetarian people.

Vegetarian Diet Plan

Morning (Empty Stomach)

Warm water with lemon

4–5 soaked almonds and 1 walnut

1 banana or apple

Breakfast

Choose any one:

Poha

Upma

Vegetable dalia

Paratha (without butter)

Oats made with water or plant milk

Idli–sambar

Avoid: Milk tea, coffee with milk.
Use lactose-free milk or plant milk.

Mid-Morning Snack

Coconut water

Roasted chana

Papaya or melon

Lunch

2–3 chapatis

Dal (lentils)

Any seasonal vegetable

Rice (½ cup)

Salad

Pickle (optional)

Evening Snack

Black tea or green tea

Roasted peanuts

Makhana

Fruit juice (fresh)

Dinner

Khichdi

Light dal

Vegetable curry

Chapati (1–2)

Before Bed

Chamomile tea or warm water

Non-Vegetarian Diet Plan

Breakfast

Boiled eggs

Omelette with vegetables

Whole wheat toast

Black tea or plant-based milk tea

Lunch

Chapati or rice

Dal

Grilled chicken

Fish curry (without cream)

Vegetable salad

Evening Snack

Boiled eggs

Chicken soup

Fruit bowl

Dinner

Light chicken curry

Fish with salad

Khichdi with chicken pieces (optional)

Foods to Avoid

These foods contain high lactose and should be avoided or limited:

Cow/buffalo milk

Cream

Butter (in large amounts)

Cheese spreads

Ice cream

Milk chocolate

Milk sweets (kheer, rabri, barfi)

Paneer (if symptoms are severe)

Milk tea

Milk coffee

Lassi (sweet)

Foods You Can Eat Safely

Low-Lactose or Lactose-Free Foods

Hard cheese (cheddar, Swiss)

Curd/yogurt (many people can digest it)

Lactose-free milk

Plant milks (almond, soy, oat, coconut)

Buttermilk in small amounts

Calcium-Rich Foods (Non-Dairy)

Almonds

Ragi (finger millet)

Soybeans

Tofu

Broccoli

Spinach

Sesame seeds (til)

Figs (anjeer)

Oranges

Vitamin D Foods

Eggs

Fish

Sunlight exposure 10–15 minutes

Fortified cereals

Lifestyle Tips

✔ Eat smaller meals

Avoid large quantities of dairy at once.

✔ Check food labels

Many foods contain hidden lactose:

Bread

Biscuits

Chips

Salad dressings

Instant soups

Packaged foods

✔ Build gut health

Use probiotics regularly.

✔ Try dairy after meals

Dairy digests better when taken with food, not on an empty stomach.

✔ Exercise daily

Keeps metabolism strong.

✔ Stay hydrated

Especially if you get diarrhea.

Frequently Asked Questions (FAQ)

1. Is lactose intolerance the same as milk allergy?

No. Milk allergy is dangerous and involves the immune system.
Lactose intolerance only affects digestion.

2. Can lactose intolerance go away?

Primary intolerance cannot be reversed.
Secondary intolerance improves after treating the underlying cause.

3. Can I eat paneer?

Hard paneer is low in lactose; many people tolerate it. Test small amounts.

4. Is curd safe?

Yes. Fermentation breaks down lactose. Many intolerant people digest curd easily.

5. Can babies have lactose intolerance?

Rare, but possible. Mostly temporary.

Conclusion

Lactose intolerance is a very common digestive condition in which the body cannot digest lactose due to a lack of lactase enzyme. It is not dangerous and does not cause permanent damage, but it can cause discomfort if dairy is consumed without control.

With proper understanding, diagnosis, and management, a lactose-intolerant person can live a completely normal and healthy life.
By choosing the right diet, using lactose-free alternatives, probiotic foods, and calcium-rich non-dairy options, symptoms can be fully controlled.

If symptoms are severe or persistent, always consult a doctor or nutrition expert.