Simply put, lactose intolerance is the inability of an individual to digest lactose, which is a milk sugar. This complication often leads to undesirable side effects.
Lactose intolerance arises due to the deficiency of the lactase enzyme, which is responsible for the catalytic hydrolysis of the lactose into glucose that can be easily absorbed into the blood.
The problem is referred to as hypolactasia.
To some extent, hypolactasia may be congenital. Such victims may not even be able to digest human milk. You should note that lactose intolerance is not milk allergy.
This is because it is not an immune response due to the presence of milk proteins.
The manifestations of lactose intolerance include flatulence, bloating, cramps, vomiting, rumbling stomach/stomach upsets, nausea, and diarrhea.
Normally, most mammals cease lactase production after weaning because they do not need it then.
You may have already realized that it is only humans who continue to consume milk long after weaning even into their adulthood.
Some studies have shown that some human populations have developed lactase persistence into their adulthood, enabling them to digest the lactose in milk from cattle and goats.
People who suffer from #lactoseintolerance do not produce lactase enzyme to digest lactose in milk Click To Tweet
These symptoms are as a result of gas production in the small intestine. The lactose sugar cannot be absorbed directly through the walls of the small intestine because it is a disaccharide.
The sugar passes to the colon where the colon bacteria ferments it.
The fermentation process produces large amounts of hydrogen, carbon IV oxide, and methane. The mixture of gases is responsible for all the symptoms manifested by a lactose intolerant individual.
The prevalence of lactose intolerance varies greatly with exposure to dairy products. Those who access dairy products much readily tend to be more tolerant to lactose.
This is because the exposure encourages their bodies to continue producing the enzyme.
On the other hand, those who are less exposed to the dairy products tend to be more intolerant to the lactose because their bodies cease to produce the lactase enzyme.
However, there are exceptions to this observation and may be associated to genetics.
Causes of Lactose Intolerance
Lactose intolerance arises due to deficiency of lactase enzyme. The deficiency of the enzyme can be traced to the following causes
- Genetic variations: – lactose persistence has been traced to a specific allele in the genome. When this allele lacks in the genome, the body produces minimum or non-existent amounts of lactase. Most of the cases of lactose intolerance in adults have been traced to this primary cause.
- Acquired deficiency: – considered to be the secondary cause of lactose intolerance. It arises from the injury to the ileum at infancy. The injury may be due to gastroenteritis, intestinal parasites, the effects of chemotherapy, or diarrhea.
- Congenital deficiency: – this is a very rare genetic disorder, which impedes lactase production right from birth. These individuals cannot digest breast milk. The Finnish commonly exhibit this class of lactase deficiency.
Before the advancement of technology to produce lactose free dairy products and soybean derived baby formulas, the babies born with congenital lactose deficiency never survived.
- Developmental deficiency: – affects babies born prematurely. It is only temporary and always disappears soon after the baby fully develops.
Causes of #lactoseintolerance: genetics, acquired deficiency, congenital deficiency, & developmental… Click To Tweet
How do you diagnose lactose intolerance?
Listed below are the tests you can carry out to confirm lactose intolerance.
Hydrogen in breath test
By far, this is the most accurate test for lactose intolerance. It involves consumption of about 20 grams of lactose made into a solution after fasting for more than 12 hours, preferably overnight.
Since the colon bacteria will metabolize the substrate to produce the gas mixture discussed previously, the gas will be traced in the person’s breath by doing a chromatography test. The procedure takes between two to three hours to finish.
Stool acidity test
This test is best suited for diagnosing lactose intolerance in infants. The infant is given lactose to drink and the stool tested.
Those who are tolerant will digest the lactose and absorb it. Those who are intolerant to lactose will have the lactose reach the colon.
Here, the colon bacteria will metabolize the lactose to produce the mixture of gases. This mixture of gases produces acidity in the stool.
The confirmation of acidity in the infant stool after consuming lactose is a confirmation of intolerance.
Stool sugar chromatography
This test identifies traces of sugar in the stool. It is not a very reliable means of identifying lactose intolerance in individuals due to the chemical changes that take place to the lactose in the intestines.
Intestinal biopsy can confirm lactose intolerance in an individual who has elevated levels of hydrogen in their breath after consuming lactose.
By using the gastrointestinal endoscopy equipment, the medical practitioner can be able to identify the deficiency of lactase enzyme in the duodenum.
Blood sugar test
The blood sugar levels of the lactose tolerant individuals will show a significant boost after consuming lactose. This is a different observation from the lactose intolerant individuals who will remain level even after consuming lactose.
This is because the tolerant individuals are able to break down the complex sugar (lactose) into simple glucose that the body can absorb.
The intolerant individuals are not able to break down the complex sugar into glucose. The lactose broken down into glucose is responsible for the spike in blood sugar.
After fasting overnight, blood is drawn and tested for blood sugar then the individual is given lactose to ingest. The blood test is repeated after intervals of half an hour, then one-hour, two hours, and three hours.
If the individual is unable to absorb the lactose, there will be insignificant rise in blood sugar.
Lactase persistence in adults is controlled by polymorphic allele in the genes. The procedure involves extraction of DNA material from the blood or saliva of the individual.
Following a matching band of colors, it will be possible to detect whether the person is lactose intolerant or not.
Dairy Products that contain lactose
Lactose is a water-soluble milk sugar. It is often found in the whey portion of the milk when making cheese. The following dairy products contain lactose
Fluid milk: – has high lactose content of up to 9% in human milk, 4.7% cow milk, 4.8% buffalo milk, and 4.9% yak milk.
Cheese: – fermentation and other cheese making processes reduce lactose content in cheeses. Hard cheeses like Cheddar may contain up to 10% lactose of the whole milk used to make that given cheese sample. Additional cheese ripening processes degrade the lactose to practically nothing after some period. Lactose content is not usually indicated on the cheese labels.
Sour cream: – when made using the traditional methods, the lactose content may be tolerable but modern manufacturers add milk solids into the product raising lactose content.
Yoghurt: – has reduced lactose content due to the action of yoghurt bacteria. These bacteria produce lactase, which catalyzes the hydrolysis of lactose. Traditionally made yoghurt is good for the lactose intolerant because it contains the lactase enzyme produced by the culture bacteria.
Butter and ghee: – has minimal lactose because butter making process excludes most water components of the milk. Since lactose is insoluble in the milk fat, it is separated from the butter during butter processing. Cultured butter will introduce bacteria to break down the remaining lactose in butter. Clarified butter contains minimal amount of lactose, making it good for the lactose intolerant individuals.
Non-dairy products that contain lactose
It is always important to read the labels of the commonly used non-dairy food products as manufacturers often add dairy products to them. Some of the non-dairy products you may find to contain lactose include the following:
- Bread and other processed wheat products such as waffles, pancakes, biscuits, cookies, doughnuts, frozen waffles and pancakes, toaster pastries, and sweet rolls
- Processed breakfast cereals, potato chips, corn chips, and other processed snacks
- Processed meats such as bacon, sausage, hot dogs, and lunch meats
- Margarine, salad dressings, protein powders and bars
- Candies, nondairy liquid and powdered coffee creamers, and nondairy whipped toppings
Dealing with lactose intolerance
The best medicine for lactose intolerance is to avoid lactose at all costs. If the route of avoidance is out of question, supplementation may be necessary.
It is possible to industrially produce lactase by using Aspergillus spp. fungi. You can obtain the β-galactosidase enzyme as a tablet supplement over the counter without prescription.
One needs to take the supplement at the same time they are taking the lactose-laden food for the supplement to be effective. It works best in an acidic environment; however, too much acid can denature it and render it useless.
Behrendt, M., Keiser, M., Hoch, M., & Naim, H. Y. (2009). Impaired trafficking and subcellular localization of a mutant lactase associated with congenital lactase deficiency. Gastroenterology, 2295-2303.
Beja-Pereira, A., Luikart, G., England, P. R., Bradley, D. G., Jann, O. C., Bertorelle, G., . . . Erhardt, G. (2003). Gene-culture coevolution between cattle milk protein genes and human lactase genes. Nature Genetics, 311-313.
Eddleman, H. P. (1999, February 6). Composition of Human, Cow, and Goats Milk. Retrieved from Goatworld.com: http://www.goatworld.com/articles/goatmilk/colostrum.shtml
Roy, B., Nwakakwa, S., & Khurana. (2006, July 5). Lactose Intolerance. Retrieved from eMedicine.
Swagerty, D. L., Walling, A. D., & Klein, R. M. (2002). Lactose Intolerance. American Family Physician, 1845-1850.
Swallow, D. (2003). Genetics of lactose persistence and lactose intolerance. Annual Review of Genetics, 197-219.
Vesa, T. H., Marteau, P., & Korpela, R. (2000). Lactose intolerance. Journal of the American College of Nutrition, 165-175.