Poor Leonard. He is always being teased due to his lactose intolerance. When he eats yogurts and ice-creams, he "produce copious amounts of methane" AKA farting, diarrhea, irregular bowel movements and cramping. These are symptoms of those suffering from lactose intolerance when they eat dairy products.
He is not the only one though. Real life chef Eva Kende shares her experience as a lactose intolerant individual living with 2 other family members with severe lactose intolerance. She has ran 35 years of a lactose free household and introduces solutions and alternative food to those with the same fate in her website: Eva's Kitchen.
Another lactose intolerant individual, Jamie Forrest, a columnist and cheese expert for "Serious Cheese" articles at seriouseats.com, recently discovered he had severe reactions to dairy products after eating gelato. Ironic isn't it? Read more of his misadventures here: Serious Cheese: What Happens When a Curd Nerd Becomes Lactose Intolerant?
So what is Lactose Intolerance?
As you all know, lactose is a sugar found in milk and dairy products. Lactose intolerance is when the body is unable to digest and absorb lactose in the duodenum of the small intestine. This is because there is low levels or absence of lactase in the small intestine lining, the enzyme that hydrolyze lactose into galactose and glucose.
Since lactose is not broken into glucose and galactose, the small intestine is unable to absorb glucose and galactose in, and so the lactose is carried on to the colon. Bacteria dwelling in the colon then ferments the lactose, producing gas (thus the farts) which also cause pressure on the intestinal walls resulting in cramps and diarrhea. Usually this happens within 24 hours of consumption.
Let's take a closer look to the main character in this biochemical intolerance:
LACTASE! (lactase-phlorizin hydrolase) |
Thus what happened in Leonard's body is that there is very low level or absence (for some people) of lactase enzyme.
Plenty of researches have been done to pin-point the causes of this intolerance. With better understanding, correct diagnosis can be done and treatment can reduce or eliminate symptoms effectively.
1) Causes
There are three types of causes. First is genetics, followed by diseases and recently, researchers find that improper protein structure is also responsible.
Genetics
In our body, the gene that codes for lactase, called LCT, can exist as 2 forms. If one has the lactase-persistent type, he is able to digest lactose. However if this type is absent, then he cannot digest lactose effectively. As you get older, after age of 5, the LCT gene becomes imbalance and this leads to lower production of lactase. Thus leading to lactose intolerance. [3]Diseases
Diseases that affects lactose intolerance are such as celiac disease, infectious enteritis, or Crohn’s disease, intestinal bacterial, viral or protozoan infections. These include rotavirus, the protozoan Giardia and gut trypanosomes. Endocrine control through sex and thyroid hormones and ageing, also may affect levels of lactase in the small intestine. When our body is under attack, our cells become stressed and this reduce the production of lactase, especially in gut infections.
Protein Structure
The lactase protein is sensitive to temperature and pH. If it is produced at 37 °C, it will become misfolded, enzymatically inactive and can be destroyed by trypsin. Absence of/inaccurate truncation and cleaving of pre-lactase to mature protein also affects the enzyme's function. Thus, it has to be produced at 20 °C to be functional. [2]
2) Diagnosis and Treatment
Have you ever been in this situation?
30 minutes after you had a bowl of cereal or ice cream your
stomach is cramping, it felt bloated and you kept on going in and out of the
toilet. Does this sound familiar? Or drink a glass of milk, and the next thing
you know you are running towards the washroom. If this does sound like you, you
could have lactose intolerance!
However, there isn't really anything to worry about. Studies
have shown that up to 90% of South Asian may be lactose intolerant
(http://www.pamf.org/southasian/risk/concerns/lactose.html). Lactose
intolerance is not a deadly condition, it may however be very frustrating when
you have to run to the toilet whenever you eat your favorite sundae. Another
thing is that You can't cure lactose intolerance but you can make changes in
what and how you eat to reduce its symptoms, such as:
• Bloating
• Cramps
• Diarrhea
• Painful gas
• Nausea
Getting a diagnosis
Visit your doctor if you think that you may be lactose
intolerant. Your doctor may ask you to keep a diary of what you eat and drink,
any symptoms experienced, and prevent taking certain food to see if the
symptoms disappear. Sometimes doctors may also suggests to avoid taking any
lactose or dairy products for two weeks and see if it helps to relieve the
symptoms. This will provide further evidence that you are lactose intolerant.
Further testing may be done to confirm the diagnosis:
Hydrogen breath test
The hydrogen breath test is a very simple and easy one as the air we breathe out have very little hydrogen. Thus if the body does not digest lactose properly, there will then be a build up of hydrogen in the intestine and eventually hydrogen is in the breath*. The test measures the amount of hydrogen(in ppm) in your breath after you drink lactase solution. After a few hours, if your breath contains a large amount of hydrogen (more than 20ppm above the amount of hydrogen in your breath before drinking the lactase solution), it is likely that you are lactose intolerant!
The hydrogen breath test is a very simple and easy one as the air we breathe out have very little hydrogen. Thus if the body does not digest lactose properly, there will then be a build up of hydrogen in the intestine and eventually hydrogen is in the breath*. The test measures the amount of hydrogen(in ppm) in your breath after you drink lactase solution. After a few hours, if your breath contains a large amount of hydrogen (more than 20ppm above the amount of hydrogen in your breath before drinking the lactase solution), it is likely that you are lactose intolerant!
Lactose Tolerance test
This is a blood test that measures the increase in the
amount of glucose in your blood after drinking lactose solution. If you can
recall, lactose is broken down by lactase to glucose and galactose. Thus, if
you are lactose intolerant, in other words have low level of lactase enzyme,
your blood glucose level will either rise very slowly or not at all because
your body has not digested the lactose.
Stool Acidity Test
This test is for infants and children for lactose
intolerance. The reason is because lactose tolerance test and hydrogen breath
test requires large doses of lactose, which are dangerous for young children
with lactose intolerance. This test measures the amount of acid in stool
sample. If the child is lactose intolerant, high amount of fatty acid, such as
acetate, is present. This is the result of the product of fermentation of
undigested lactose by the bacteria in the colon.
Intestinal/Small Bowel Biopsy
This is the most direct test for lactose intolerance, by
directly measuring lactase level in the intestinal lining using endoscope. Low
level of lactase indicates lactose intolerance. It is very rare because this is
an invasive surgical procedure.
Treatment
Common approach for patients with lactose intolerance are
usually by excluding milk and dairy products from their diets. However, this
method may affect the intake of calcium and vitamins by the body. Therefore, it
is important to realize that not all patients with lactase deficit, only
symptomatic ones, have to be treated. There are 2 ways to manage lactose
intolerance: Non-pharmacological and pharmacological approach.
Non-pharmacological approach
Initially, milk and dairy products are temporarily avoided
for 2-4 weeks to obtain remission of symptoms. Subsequently, a gradual
re-introduction of low-lactose dairy products can be suggested, considering the
individual threshold dose. (Most individual can tolerate up to 12g of lactose
without significant symptoms.)Fermented milk and matured milk products in the
diet, milk with pre-hydrolyzed lactose via treatment with lactase supplements,
consumption of milk together with other food and distribute lactose intake over
the day are several methods to overcome possible symptoms. Paolo Usai-Satta et
al have mentioned an interesting approach to increase the threshold dose by
increasing the lactose load gradually, giving the colon time to adapt. Since
lactase from intestinal brush border is not an inducible enzyme, the reduction
in symptoms may be explained by colonic adaptation.
Pharmacological approach
If the measure suggested here are not enough to alleviate
symptoms, pharmacological methods can be taken. Enzyme replacement therapy with
lactase from nonhuman sources to hydrolyze lactose is another important
approach of prevention. There are multiple commercially available lactase
supplements containing variable amounts of beta-galactosidase from a variety of
sources[5,6,7]. Ingestion of probiotics, nonpathogenic and have lactase
intracellularly, may aid in lactose digestion by the intolerant patients. These
microorganisms such as lactobacillus and saccharomyces are added to food
product or used as supplements [1,3]. Yoghurt containing live cultures
providing endogenous beta galactosidase is an alternative source of calories
and calcium, and is well tolerated by many lactose-intolerant patients.
However, one must take precautions as traces of milk or its derivatives added
after fermentations can cause symptoms. Daily supplements of calcium and vitamin
D are also recommended to fulfill the dietary calcium recommendation of
1200-1500mg for adolescents. In adults, the amount varies according to gender
and menopausal status. [3]Thus we can achieve the goal of treatment , which is
to alleviate symptoms while maintaining adequate intake of calcium and vitamin
thus preventing secondary bone diseases related to milk-restricted diets.
We hope that all 'Leonard's out there can benefit from these findings in our article to reduce their discomfort and prevent the social embarrassment in this video.
CAUTION! - EXTREME CASE OF LACTOSE INTOLERANCE. DO NOT TRY THIS AT HOME IN PUBLIC.
REFERENCES:
1) P Usai-Satta, M Scarpa, F Oppia, F Cabras, June 6, 2012, Lactose malabsorption and intolerance: What should be the best clinical management? [pdf] Available at:<http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3437438/>[Accessed 4 January 2013]
2) R Jacob, K Peters,H Y. Naim, December 18, 2001, The Prosequence of Human Lactase-Phlorizin Hydrolase Modulates the Folding of the Mature Enzyme* [pdf] Available at: <http://www.jbc.org/content/277/10/8217.full.pdf+html>[Accessed 4 January 2013]
3) R Mattar, D Ferraz de Campos, Mazo, F J Carrilho, July 4, 2012, Lactose intolerance: diagnosis, genetic, and clinical factors. [pdf] Available at: <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3401057/>[Accessed 4 January 2013]
6) Montalto M, Curigliano V, Santoro L, Vastola M, Cammarota G, Manna R, Gasbarrini A, Gasbarrini G. Management and treatment of lactose malabsorption. World J Gastroenterol. 2006;12:187–191. [PubMed]
7) Montalto M, Nucera G, Santoro L, Curigliano V, Vastola M, Covino M, Cuoco L, Manna R, Gasbarrini A, Gasbarrini G. Effect of exogenous beta-galactosidase in patients with lactose malabsorption and intolerance: a crossover double-blind placebo-controlled study. Eur J Clin Nutr. 2005;59:489–493. [PubMed]
8)NHS,UK. 2011. Lactose Intolerance- Diagnosis. Available at: <http://www.nhs.uk/Conditions/lactose-intolerance/Pages/Diagnosis.aspx>
[Accessed on 12 January 2013]
9)WebMD, LLC. 2011. Digestives Disorders Health Centres. Available at: <http://www.webmd.com/digestive-disorders/diagnosing>
[Accessed on 12 January 2013]