Lactose Intolerancve

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University of KhartoumUniversity of Khartoum

College of Graduates studyCollege of Graduates studyMSC of dairy production and teMSC of dairy production and te

Seminar about:

LACTOSE INTOLERANCE

Prepared by:Prepared by:Shimaa Ahmed IbrahimSafinaz AadelEilaf Suliman Khalil


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Introduction Definition of lactose

Nutritional aspect of lactose

Definition of lactose intolerance

Occurrence of lactose intolerance

Lactase

Types of lactose intolerance

Prevalence of Lactose Maldigestion

Symptom, diagnosis and treatment

Summary and conclusion

References

Contents


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IntroductionIntroduction

Dairy products are an important source ofmany nutrients including calcium, high-quality protein, potassium, phosphorus,and riboflavin. Dairy foods are animportant part of the diets of children andadults


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Lactose

Lactose(milk sugar) is the principlecarbohydrate in human and animal milk.Human milk contains an average of 7% lactose,while whole cows milk contains 4.8%.

Lactose is a disaccharide made up of equalportions of two monosaccharide, glucose andgalactose .


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Average content of lactose indifferent dairy products


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Lactose is not only present in milk at 5%,

but also in a broad range of dairy productsand processed foods such as ice cream oreven salad sauces and sausages, as well as

pharmaceuticals.


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Nutritional aspect of lactoseNutritional aspect of lactose

Lactose has 2 major nutritionallyundesirable consequences:

Lactose intolerance

Glactosaemia

Tolerance to milk is sometimes affected byfactors unrelated to its lactose content, such aspsychological factors or cultural attitudestoward milk.


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Milk Allergy and LactoseIntolerance

Lactose intolerance:Lactose intolerance:is the inability or insufficient ability to digest

lactose, a sugar found in milk and milk products.

Lactose intolerance is caused by a deficiency of theenzyme lactase.Milk allergy:Milk allergy:

is a reaction by the bodys immune system to

one or more milk proteins and can be life threateningwhen just a small amount of milk or milk product isconsumed. Milk allergy most commonly appears inthe first year of life.


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LactaseLactase

A unique intestinal enzyme, lactase, a beta-galactosidase, is needed to hydrolyze lactose andone of the five disaccharidases enzymes locatedon the brush border of the intestinal epithelium.

Lactase (also known as lactose-phlorizinhydrolysis, or LPH), a part of the -galactosidasefamily of enzymes .

1927 amino acids Lactase Structural Gene, LCTthe gene is located

on the second chromosome


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it is a glycoside-hydrolase involved in thehydrolysis of the disaccharide lactose intoconstituent galactose and glucose monomers.


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Lactase is present

predominantly alongthe brush bordermembrane of thedifferentiated

enterocytes lining thevilli of the smallintestine.


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The surface of the small intestine composed of hundredsof villi, tiny finger-like structures and have additional

extensions called microvilli which make up brushborder of the absorptive epithelial cells (enterocytes)

This arrangement of the epithelium maximises thesurface area through which the body may absorbnutrients. The enzymes, such as lactase, are anchored to

the surface of the brush border.


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Types of Lactase DeficiencyTypes of Lactase Deficiency

Congenital:Very rare

Primary:

Develops after 2 years of ageSecondary:

Usually resolves in 1-2 weeks


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Congenital causes of lactose intoleranceCongenital causes of lactose intolerance(CLD)(CLD)

Lactase deficiency may occur because of acongenital absence (absent from birth) oflactase due to a mutation in the gene that is

responsible for producing lactase. This is a very rare cause of lactase

deficiency, and the symptoms of this type of

lactase deficiency begin shortly after birth.


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Primary lactase deficiencyPrimary lactase deficiency

Develops over time and begins after aboutage 2 when the body begins to produce lesslactase.

Most children who have lactase deficiency

do not experience symptoms until lateadolescence or adulthood

Some people inherit a gene from their

parents that makes it likely they willdevelop primary lactase deficiency(Genetic link)


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secondary lactase deficiency

A temporary lactase deficiency can develop in

babies when there is inflammation or injury inthe digestive tract that damages the cells thatproduce the enzyme.

The inflammation may be caused by a bacterial

or viral infection, or a food allergy. todistinguish it from primary congenitalalactasia.

The cells rapidly return to normal when theinfection subsides, or the food allergen is

removed from the child's diet, and the usuallevel of lactase production is quickly re-established.


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The prevalence is above 50% in SouthAmerica, Africa, and Asia, reaching almost 100%in some Asian countries. In the United States, theprevalence is 15% among whites, 53% amongMexican- Americans and 80% in the Blackpopulation. In Europe it varies from around 2%in Scandinavia to about 70% in Sicily Australia

and New Zealand have prevalence's of 6% and9% respectively. In general, it can be stated that about twothirds of the world adult population is lactase

non-persistent.

Prevalence of Lactose Maldigestion


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(Swallow and Hollox, 1999)

The prevalence of lactase deficiency

coincides with the ethnic background


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Symptom


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Specific Tests

DIRECT INDIRECT

Enzyme Assay

Quantitation of small

bowel lactase activity

Intestinal Biopsy

Hydrogen Breath Test

Lactose ToleranceTests

Blood Glucose Test

Lactose-Ethanol Load Test

Stool Acidity Test

Urinary Galactose


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Diagnosis


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1.1. Fecal Reducing Substances Test :Fecal Reducing Substances Test :

considered by many clinicians as the mostreliable. After a drink containing lactose, thefeces are collected and Fehlings solution added.The presence of undigested lactose in the stool

will be indicated by a change in color.

2. HydrogenHydrogen BreathBreath TestTest::

The person drinks a lactose-loaded beverage and

then the breath is analyzed at regular intervals tomeasure the amount of hydrogen. Normally, verylittle hydrogen is detectable in the breath, butundigested lactose produces high levels of

hydrogen.


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How is lactose intolerance managed?

1. Most people with lactose intolerance cantolerate some amount of lactose in their

diet. Gradually introducing smallamounts of milk or milk products may

help some people adapt to them withfewer symptoms.

2. It is interesting to note that both preterm

and term infants in the first few monthsof life do not completely hydrolyze thelactose in their mothers milk.


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2. The milk is UHT-heated, then a smallquantity of anaseptic preparationof the enzymelactase is added,and the milk isasepticallypackaged.

After a few days of storage, thelactose is almost fullyhydrolyzed into glucose andgalactose. This has not becomea success. The product is

relatively expensive, and mostconsumers consider the tastetoo sweet. Lactose intolerantpeople are better offconsuming fermented milks


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3. Add lactase enzyme to fluid milkLactaidTMCactraseTMDairyEaseTM

4. Lactose intolerant people are better offconsuming fermented milks and cheeses

which reduce the lactose about 25% andcontain -galactosidase.

5. Polymer Poly(D,L-lactide-co-glycolide) PLGAmicroparticles.

6. Pharmaceutical preparations of fungal oryeast-derived -galactosidase.


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6. Lactose-free and lactose-reduced milk and

milk products :- Although an increasing variety of such pre

treated low lactose dairy products isavailable, it is still often inconvenient foraffected persons to avoid the uptake oflactose.

- Moreover, omitting dairy products has the

disadvantage of losing a major source ofcalcium and proteins.


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7. Milk composition can be manipulated bynutritional means or utilizing natural

genetic variation. Genetic improvement canbe attained through exploitation ofbetween- (cross-breeding) or within-

(selection) breed variation, while recentadvances in genetic engineering offer thepromise of changes not previously possibleusing traditional nutritional and genetic

approaches .


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8.Biotechnology

French researchers have developed transgenicmice that expressed intestinal lactase in the

mammary gland and produced low-lactose milk. A DNA construct containing the rat intestinal

lactase-phlorizin hydrolase cDNA under thecontrol of the mammary specific alphalactalbumin promoter was introduced into mice.

Transgenic mice expressed the foreign lactaseconstruct during lactation and secreted lactase

into milk.


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Treatment of lactose intolerance


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Conclusion andConclusion and

RecommendationRecommendation 70 % of the world adult population have

hypolactasia

Feasible diagnostic methods are available

The majority tolerate small amounts oflactose

The most sensitive need lactose-freeproducts

More studies should be done


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GLOSSARYOF TERMSGLOSSARYOF TERMS

Lactase Beta-galactosidase:an enzyme of the hydrolase class that catalyzes thehydrolysis (digestion) of lactose, a disaccharide, into itsmonosaccharide components of glucose and galactose.

Lactase is present on the brush border of the intestinalmucosa where such digestion takes place.

Lactose:

A disaccharide which yields upon hydrolysis themonosaccharides, glucose and galactose. Since milk is thesole natural source of lactose, it is commonly referred to asmilk sugar.


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Milk allergy:

is a reaction by the bodys immune systemto one or more milk proteins and can be lifethreatening when just a small amount of

milk or milk product is consumed. Milkallergy most commonly appears in the firstyear of life, while lactose intolerance occursmore often in adulthood.


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Lactose maldigestion Reduced digestion of lactose dueto low lactase activity.

Low lactase activity or hypolactasia:

Low levels of the intestinal enzyme, lactase, in thebrush border membrane. Low lactase activity (lactasedeficiency) can be measured directly by small bowelbiopsy, or indirectly using the lactose tolerance test orthe breath-hydrogen test.

Lactose malabsorption (LM):

the inability to break down lactose because of reducedconcentrations of an enzyme called lactase phlorizinhydrolase (lactase, or LPH) in the small intestine

is fairly common in adults (1, 2).


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References Advanced Dairy Chemistry, Volume 3: Lactose, Water,

Salts and Minor Constituents. Third Edition Edited by P. L.H. McSweeney and P. F. Fox University College, Cork,Ireland13. 2009

Dairy processing ,Improving quality, Edited by GerritSmitFirst published 2003, Woodhead Publishing Limited

and CRC Press LLC

Handbook of dairy food and nutrition ch8 2000 by CRCPress LLC Cultural Adaptation Lactose Malabsorption

Advanced Dairy Chemistry C.J.E. Ingram and D.M.

Swallow Janaki Babu, Sunil Kumar, P Babu, Jaishri H Prasad, and

Uday C Ghoshal, Frequency of lactose malabsorptionamong healthy southern and northern Indian populations

by genetic analysis and lactose hydrogen breath andtolerance tests October 2010


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Lactose Intolerance- Tuula H. Vesa, PhD, Philippe Marteau,

PhD, MD, and Riitta Korpela, PhD Journal of the AmericanCollege of Nutrition, Vol. 19, No. 2, 165S175S (2000)Published by the American College of Nutrition.

National Institutes of Health - NIH Consensus DevelopmentConference: Lactose Intolerance and Health February 2224,

2010.

Janice M. Joneja, Ph.D., RD ( FACT SHEET) Journal of theAmerican dietetic association improved lactose digestiontolerance and digestion May 2000.

M. Di Stefano a, V. Terulla b, P. Tanaa, S. Mazzocchi a, E.Romerob, G.R. Corazza a, M. Di Stefano et al. / Digestiveand Liver Disease 41 (2009) 474479. Genetic test for lactasenon-persistence and hydrogen breath test:Is genotype betterthan phenotype to diagnose lactose malabsorption


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Gerda Ratzinger 1, Xueyan Wang 1, Michael Wirth, Franz

Gabor .; G. Ratzinger et al. - Journal of Controlled Release147 (2010) 187192. Targeted PLGA microparticles as anovel concept for treatment of lactose intolerance

Tuula H. Vesa, PhD, Philippe Marteau, PhD, MD, andRiitta Korpela, PhDJournal of the American College of

Nutrition, Vol. 19, No. 2, 165S175S (2000) LactoseIntolerancePublished by the American College of Nutrition

Understanding Lactose Intolerance physician committeefor responsible medicine.

Jost B, Vilotte J-L, Duluc I, Rodeau J-L, and Freund J-N.1999. Production of low-lactose milk by ectopic expressionof intestinal lactase in the mouse mammary gland. NatureBiotechnology 17:160-164.


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