- What is lactose intolerance
- What are the symptoms of lactose intolerance?
- Genetics of lactose intolerance
- Meeting your calcium requirements with a dairy-free diet.
What is lactose intolerance?
Lactose intolerance is a digestive disorder caused due to an inability to digest lactose, a sugar found in milk and other dairy products. Lactose is broken down by an enzyme called lactase, which is produced in the small intestine.
Types of lactose intolerance?
WATCH: The Genetics of Lactose Intolerance
There are four types of lactose intolerance with a different cause for each class.
Primary lactose intolerance
This is the most common type of lactose intolerance. Most of us are born with enough lactase enzyme to digest lactose.
By the age of 5 (in African Americans, by 2), the lactase levels decrease, making lactose digestion challenging for our bodies.
Primary lactose intolerance is more common in people with Asian, African, and Hispanic ancestry.
Secondary lactose intolerance
Low lactase secretion can occur due to intestinal conditions like Crohn's disease and celiac disease. Certain injuries and surgeries can also lower lactase production and an inability to digest lactose, causing secondary lactose intolerance.
Developmental lactose intolerance
It occurs in premature babies. It usually lasts only for a short duration after birth and goes away on its own.
Congenital lactose intolerance
This is a rare type of genetic disorder. It is caused when a defective lactase-producing gene is passed on from both the parents to the offspring(s). As a result, there is a complete absence of lactase in the child from birth.
Symptoms of lactose intolerance
Typically, the symptoms appear anywhere between 30 minutes to 2 hours after consuming any dairy products. Some commonly observed symptoms include:
- Bloating
- Abdominal pain or cramping
- Diarrhea
- Flatulence
- Nausea, sometimes accompanied by vomiting.
The severity of symptoms depends on the amount of lactose consumed and the amount of lactase produced by the individual.
Most people with lactose intolerance can consume some lactose without getting symptoms.
For how long do the symptoms persist?
The symptoms persist until your body manages to eliminate the lactose fully.
It could be about 12 hours for some individuals, while it could be much longer for others.
When the body forces out the undigested lactose through your digestive system, you might experience pain and discomfort.
Digestive system transit time (the time is taken to digest and eliminate any substance) can be tracked using activated charcoal capsules dosed according to your weight.
What foods to avoid if you are lactose intolerant?
People with a mild case of lactose intolerance can have up to 12 grams of lactose without experiencing symptoms or maybe a few mild symptoms
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Lactose intolerance diagnosis
The primary test that your physician may ask you to take up is abstaining from dairy products and check to see if the symptoms subside.
Your stool samples can also help in making the diagnosis- a watery, loose, or foamy stool can indicate that you are lactose intolerant.
However, to confirm the diagnosis, the following tests are mostly used:
Hydrogen breath test
- Uses the measurement of hydrogen in the breath to diagnose several conditions
- If the lactose is required to breathe into a machine after 12 hours of fasting
- Once the hydrogen levels are measured, a small amount of lactose is consumed, post which additional samples of breath are collected and analyzed for hydrogen every 15 minutes for up to five hours
- High levels of hydrogen may warrant the diagnosis of lactose intolerance
Lactose tolerance test
- Measures your blood sugar after you consume lactose-containing foods
- Post-midnight of the day before you take the test, you should refrain from eating or drinking anything
- On the day of the trial, you will be asked to consume a liquid containing lactose (which might provoke symptoms such as gas or abdominal pain)
- Your blood will then be tested every 30 minutes for the next 2 hours
- You might test positive for lactose intolerance if your blood sugar levels do not rise
- This test is not meant for infants, young children, or the diabetic
Can you test for lactose intolerance at home?
Yes, you can do this simple test for lactose intolerance at home:
- Consume lactose-containing products (like skimmed milk) and watch out for symptoms like abdominal pain, bloating, or diarrhea
- Exhibition of these symptoms might be suggestive of lactose intolerance
- You might want to repeat this test using lactase-treated milk and check whether the symptoms subside
- If they do, it could ascertain that you are lactose intolerant
- But it is always better to confirm the diagnosis with your health care practitioner
Genetics and Lactose Intolerance
Studying the mutations- C/T-13910 and G/A-22018 located upstream the gene that codes for the enzyme lactase-phlorizin hydrolase can be a useful tool to diagnose hypolactasia (The condition causing Lactose malabsorption).
Heredity
Primary lactase deficiency, which is the most common cause of lactose intolerance throughout the world, is caused by an inherited genetic fault running in families.
Congenital lactase deficiency or congenital alactasia is the disorder where infants suffer from not being able to digest the lactose present in breast milk or formula, causing diarrhea.
Such infants might even develop dehydration and weight loss if they do not switch to lactose-free infant formula.
Congenital lactase deficiency in infants is inherited in an autosomal recessive pattern (Both copies of the LCT gene in each cell is mutated).
The parents being individuals with the autosomal recessive condition, each carry one copy of the mutated gene, and may not experience any symptoms. However, when they both pass on the defective genes (25% chances), the infant could, as a result, be intolerant to lactose.
The type of variations in the regulatory element in the MCM6 gene inherited from one’s parents decides the ability to digest lactose in adulthood.
One copy of the altered regulatory element is enough to sustain lactase production.
Individuals who haven’t inherited such variations from either parent will have a certain degree of lactose intolerance.
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How can I increase lactose tolerance in my body?
Switch to low-lactose dairy products
Some cheese like cheddar and parmesan, probiotic yogurts, heavy creams have low lactose levels and can be added to your diet in minimal amounts.
Consume lactose-containing foods alongside other foods
When you are digesting other foods simultaneously, gastric emptying can get slower, and lactose, which makes up just a small proportion of the total food may not create many problems.
Include fermented dairy products
The bacteria present in yogurt and kefir can produce a lactase-like enzyme which can make your food to digest even though it contains lactose.
Take lactase supplements
Lactase supplements allow the breakdown lactose into glucose and galactose so that your body can absorb the sugars without experiencing symptoms
Can lactose intolerance develop during adulthood?
Except for sporadic cases, every infant can produce lactase enzymes which helps the small intestine digest the lactose sugar.
But with age, one’s lactase levels can start to decline, and it can prevent the lactose you eat from going to your colon without being digested.
The bacteria there might break down the sugar and cause flatulence and fluid in that process.
It is quite common for people to develop lactase deficiency in adulthood.
Per the NIH report, about 65% of the global population has a lowered ability to digest lactose after infancy.
The genetic factors can be equally responsible for lactose intolerance.
Your body tends to secrete the enzyme lactase only when instructed to do so by the gene LCT which can get less active over time and result in lactose intolerance.
The condition which can begin as soon as a person turns two years old, may not manifest itself until a person reaches adolescence or adulthood.
The recommended diet for lactose intolerance
The ideal diet for the lactose intolerance emphasizes on the foods to avoid more than about what to eat.
Needless to say, it is essential to avoid or reduce the amount of lactose-containing foods.
But, it is also important to read food labels to exclude canned, boxed, frozen, and prepared foods like bread, lunch meats, salad dressings, cake, cookie or pancake mixes, coffee creamers, etc., that contain lactose ingredients (like cream, cheese, butter, milk, milk solids, dried milk, whey, etc).
Excluding dairy from your diet can make you more prone to vitamin D and calcium deficiency.
Some calcium-rich, dairy-free foods include:
- Spinach
- Canned salmon or sardines with bones
- Calcium-fortified orange juice
- Raw broccoli
- Canned white tuna
- Calcium-fortified soy milk
- Dark green leafy vegetables
- Almonds
Vitamin D and calcium supplements can also be consumed upon your physician's advice.
