Okay, I’ve been experiencing symptoms of lactose intolerance for months (or years) now and perhaps I have already taken the Breath Test; it is time to verify my condition through the Genetic Test for lactose intolerance.
The test is simple; it is performed via a buccal swab (using a sterile cotton swab in the mouth) or a blood draw. The cost is higher than the Breath Test but, unlike the latter, it does not cause physiological problems in the event of a positive result. You will receive your results after a few days.
Please note: the genetic test does not provide the same information as the H2 Breath Test, but rather informs us about a possible predisposition of the body to become intolerant (we may have been intolerant for some time, we could become intolerant now, or we might become so in the future). The tests are therefore complementary rather than alternative, and we recommend taking a lactose intolerance Breath Test anyway, as it also indicates how intolerant we are to the substance TODAY.
Why a GENE test?
All of our cells have a limited lifespan and must reproduce to keep the body functioning, i.e., alive. To pass on the individual's characteristics—their character—there must be a transfer of information between cells to "train" the new ones to perform the required tasks.
How is this information transmitted? I don't want to go into too much detail, but I like to explain every point, leaving the reader the choice to skip the following paragraph.
Cellular organisms use messenger RNA (mRNA) to transmit the aforementioned genetic information (using the letters G, U, A, and C to indicate guanine, uracil, adenine, and cytosine) that directs the synthesis of specific proteins. Enzymes are proteins specialized for the catalytic function that control all metabolic events in the organism. Lactose is broken down in the intestine into glucose and galactose by a specific enzyme: the lactase enzyme. This enzyme is encoded by the “LPH” GENE mapped on chromosome 2 of our DNA. At birth, lactase levels are very high but decrease after weaning. From two years of age, there is a gradual decrease in lactase mRNA transcripts, associated with a reduction in enzymatic activity.
Over time, therefore, we lose the “instruction” to create the lactase enzyme, which is responsible for the proper digestion of lactose.
The test described here allows us to verify whether this instruction, this message, is still present within our DNA or not.
Another dense paragraph:
Specifically, adult-type lactose intolerance, also called hypolactasia, is due to a variation (polymorphism) of the genotype associated with the LPH gene. The homozygous C variant (C/C genotype), associated with lower transcription of the gene, is correlated with the lactose intolerance phenotype. About 60% of people present this anomaly. The genetic test for lactose intolerance makes it possible to distinguish those who have both healthy copies of the gene (T/T), those who have only one healthy copy (T/C), and those who have both mutated (C/C).
The subject who presents both mutated copies (C/C, POSITIVE TEST) is predisposed to lactose intolerance and, if they are already suffering from the typical symptoms of intolerance, the test confirms that they are no longer able to create the lactase enzyme (primary deficiency).
The genetic result is certain, and the subject will not be able to have stores of the enzyme in the future capable of breaking down, and thus digesting, lactose—unless administered externally, see lactase enzyme tablets-.
I emphasize, however, that to be defined as lactose intolerant, the typical symptoms of intolerance must be persistent, meaning they should not be caused by other digestive system diseases.
In the case of different, temporary issues, a positive genetic test informs us that we will become intolerant, but our current discomforts may not be related to a lactase enzyme deficiency.
Conversely, in the case of lactose maldigestion but a NEGATIVE genetic test for intolerance, we will have confirmation that our intolerance has a different, transient, and reversible character.
It will have a secondarily induced form (secondary deficiency) as a consequence of other pathologies such as, for example, damage to the intestinal mucosa following antibiotic treatment, gastroenteritis, alcoholism, celiac disease, nutritional disorders, infections of the digestive and intestinal tract, surgical procedures, or other pharmacological therapies. In this case, the solution to the symptoms should be sought with specific in-depth analyses, through tests that a good gastroenterologist will be able to recommend to you.
Do we need to prepare to take the test?
The test is simple, so the only precaution to take, in the case of a saliva swab, is not to put any substances in your mouth for the 30 minutes prior to the collection.
Therefore, NO food, candy, alcoholic or sugary drinks, coffee or tea, medications such as syrups or effervescent substances, mouthwash, or cigarette smoke. Drinking water is permitted.
In summary, the Genetic Test for lactose intolerance is a non-invasive tool approved by the scientific community and offered by major hospitals to investigate the body's predisposition to digest lactose.
It is a reliable test regarding the result, but it does not confirm that the discomfort you may have today, if not recurring for some time, is caused by permanent intolerance, as we might not be intolerant today but could become so shortly, and the symptoms we have may derive from other pathologies.
For this reason, we invite anyone who has doubts about being intolerant to first undergo a lactose intolerance Breath Test—which is cheaper—and then, if necessary, a DNA test.
In another article on our blog, you can find a description of the H2 Breath Test for lactose intolerance.
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Bibliography
- Understanding DNA, Third Edition: The Molecule and How it Works 3rd Edition by Chris R. Calladine, Horace Drew, Ben Luisi, Andrew Travers.
- Excellent agreement between genetic and hydrogen breath tests for lactase deficiency and the role of extended symptom assessment. Pohl D, Savarino E, Hersberger M, Behlis Z, Stutz B, Goetze O, Eckardstein AV, Fried M, Tutuian R. Br J Nutr. 2010.
- Excellent agreement between genetic and hydrogen breath tests for lactase deficiency and the role of extended symptom assessment. Pohl D, Savarino E, Hersberger M, Behlis Z, Stutz B, Goetze O, Eckardstein AV, Fried M, Tutuian R. Br J Nutr. 2010.
- Adult-type hypolactasia genotyping in Northern Italy: prevalence of C/T-13910 polymorphism and questions after comparison with existing data. Ghidini C, Sottini A, Zanotti C, Serana F, Marini M, Caimi L, Imberti L. Minerva Gastroenterol Dietol. 2010
- Effect of C/T -13910 cis-acting regulatory variant on expression and activity of lactase in Indian children and its implication for early genetic screening of adult-type hypolactasia. Kuchay RA, Thapa BR, Mahmood A, Mahmood S. Clin Chim Acta. 2011
- Meta-analysis: the diagnostic accuracy of lactose breath hydrogen or lactose tolerance tests for predicting the North European lactase polymorphism C/T-13910. Marton A, Xue X, Szilagyi A. Aliment Pharmacol Ther. 2012