The Milky Way Of Lactose

What is lactose and how does it affect the body

I lack the en­zymes

To prop­er­ly di­gest lac­tose

I can’t drink cow’s milk

I can’t drink milk from a goat

Yo­gurt, cot­tage cheese

Make me throw up

Please no cream in my cup

Cyn­di Lau­per, the au­thor of this song, is not the only celebri­ty who feels un­ex­cit­ed about lac­tose. The Princess Di­aries star Anne Hath­away, Amer­i­can song­writ­er Li­onel Richie and singer Car­di B are also fa­mil­iar with stom­ach cramps, nau­sea and bloat­ing caused by this car­bo­hy­drate. “It’s just not work­ing out…di­ar­rhea for three days…straight,” says Car­di B to Us mag­a­zine. Sad­ly, no dates in ice-cream shops, no warm milk for a good night’s sleep and no cheesy piz­zas for these lac­tose-in­tol­er­ant celebri­ties!

If you’ve nev­er ex­pe­ri­enced any­thing they are com­plain­ing about, you might say: “For­get lac­tose - just take milk!” But the thing is, there’s no true milk with­out lac­tose. This is a com­pound of an­i­mal ori­gin that lives in mam­mal’s milk and makes the milk sweet. That is why lac­tose is com­mon­ly called “milk sug­ar”.

By con­trast, oth­er celebri­ties don’t shy away from ex­press­ing their love to­wards lac­tose. “My milk­shake my cheat day,” says TV per­son­al­i­ty Ryan Seacrest while drink­ing his choco­late bev­er­age with mul­ti­ple straws. And there’s no bet­ter in­dul­gence than cheese in all its forms for ac­tress Anna Faris. “I love piz­za. I love pas­ta. I love great cheese. Cheese­cake and ice cream,” she says in the in­ter­view for PEO­PLE Mag­a­zine.

As you can see, lac­tose nev­er suf­fers from a lack of at­ten­tion. For what it’s worth, the ben­e­fits of milk sug­ar are im­pres­sive. While giv­ing our bod­ies an in­stant boost of en­er­gy, lac­tose helps ab­sorb cal­ci­um, zinc and cop­per op­ti­mizes the bone growth and en­cour­ages the brain and im­mune sys­tem work prop­er­ly. Lac­tose is an en­dur­ing source of a small­er car­bo­hy­drate called glu­cose, which is stored in mus­cles to be used as a fuel, es­pe­cial­ly dur­ing in­tense work­outs. There­fore, it plays an im­por­tant part in an ath­letes’ diet, help­ing them to re­cov­er af­ter ex­er­cis­ing and get ready for the next ac­tiv­i­ty. Sports­men, who don’t eat enough car­bo­hy­drates, of­ten ex­pe­ri­ence fa­tigue and mus­cle sore­ness.

And who could deny the beau­ty of its physic­o­chem­i­cal char­ac­ter­is­tics? Its bland taste and low hy­gro­scop­ic­i­ty make lac­tose a great filler and dilu­ent for pills, cap­sules and in­fant for­mu­las. Its abil­i­ty to car­ry fla­vors and col­ors of­fers unique op­por­tu­ni­ties to con­fec­tion­ers: they of­ten add lac­tose to top­pings, frost­ings and fruit pies to in­crease the to­tal solids and en­hance the fla­vor. And lac­tose’s ab­sorp­tive tal­ent won over the hearts of cof­fee lovers who ad­mire lac­tose for giv­ing their fa­vorite bev­er­age a vel­vety-smooth taste.

To­day the world pro­duces sev­er­al mil­lion tons of lac­tose ev­ery year, ob­tain­ing it from cow’s milk or as a by-prod­uct of whey. Whey is a cloudy liq­uid com­posed of wa­ter, milk sug­ar, pro­tein, vi­ta­mins, and min­er­als. It oc­curs af­ter milk is cur­dled and strained, for ex­am­ple, dur­ing cheese­mak­ing, when a cheese­mak­er sep­a­rates the milk into sol­id curds and liq­uid whey. While lac­tose wasn’t com­mer­cial­ly rec­og­nized un­til the 1960s, its in­dus­tri­al pro­duc­tion didn’t make a sig­nif­i­cant change from its orig­i­nal method of iso­la­tion.

So, how did this all get start­ed? Where did lac­tose (C₁₂H₂₂O₁₁) come from?

Sci­en­tists, who have been trac­ing the roots of lac­tose, re­fer its first ap­pear­ance to the 16th cen­tu­ry. And some re­late the very first dis­cov­ery of lac­tose to a mir­a­cle doc­tor! His name is Leon­hard Thur­neysser (1531-1596), and he served at the court of Elec­tor John George of Bran­den­burg. Thyr­neysser was the one who found lac­tose in whey. At that time, peo­ple were not fa­mil­iar with the in­ter­est­ing prop­er­ties of this sub­stance. A true en­thu­si­ast of ex­per­i­ment­ing, Thyr­neysser want­ed to see what hap­pens if he heats it up. He sim­mered and sim­mered the liq­uid in a test tube un­til the last drop of wa­ter evap­o­rat­ed. Thyr­ness­er looked at the tube: it wasn’t emp­ty. He looked more close­ly: lit­tle crys­tals showed white in­side the tube. Thyr­ness­er named the crys­tals “a key salt of milk” and quick­ly for­got about his dis­cov­ery. Ob­sessed with mir­a­cle medicine, he prob­a­bly found a new medicine herb to ex­per­i­ment with or was just too busy deal­ing with the sud­den ac­cu­sa­tions of quack­ery.

Leonhard Thurneysser []

Con­se­quent­ly, no­body no­ticed the birth of lac­tose, and the com­pound was wait­ing for its shin­ing hour and recog­ni­tion, or at least for some­one who could re­name it. Af­ter all, the “salty” name didn’t suit the com­pound’s sweet na­ture… Then in 1619, Ital­ian physi­cian Fab­rizio Bar­to­let­ti (1576–1630) re­peat­ed Thur­neysser’s ex­per­i­ment and named the crys­tals “man­na”, re­fer­ring to “man­na from heav­en” from the Bible. Po­et­ic, but still not sweet…

Over two cen­turies, ad­ven­tur­ous­ly trav­el­ing from one tube to an­oth­er, lac­tose car­ried un­cer­tain names, which couldn’t tell about its life mis­sion. Only in 1780 Ger­man-Swedish chemist Carl Wil­helm Scheele (1742-1786) made a sweet break­through when he fi­nal­ly iden­ti­fied lac­tose as sug­ar. And in 1843 French chemist Jean Bap­tiste An­dré Du­mas (1800–1884) award­ed this sug­ar with the ti­tle “lac­tose”. From Latin “lac” means “milk”, and the suf­fix -ose is used to name sug­ars. What can be more ac­cu­rate for white crys­tals with a mild sweet taste?

Lactose crystals []

Un­der the mi­cro­scope, these crys­tals look more like small tom­a­hawks rather than can­dies. And the mol­e­cule of lac­tose (342.2 g/mol) rep­re­sents two in­de­pen­dent sug­ars. They are galac­tose and glu­cose species linked to­geth­er by an oxy­gen atom.

In­ter­est­ing­ly, these sim­ple sug­ars have the same for­mu­la (C₆H₁₂O₆) and mo­lar mass (180.156 g/mol),- but a slight­ly dif­fer­ent ar­range­ment of atoms. Be­cause of that dif­fer­ence, galac­tose fea­tures a high­er melt­ing point, while glu­cose has a sweet­er taste. As both com­pounds are made of a sin­gle sug­ar mol­e­cule, they are called “monosac­cha­rides”. And lac­tose, which has both sug­ars in its com­po­si­tion, be­longs to the class of dis­ac­cha­rides.

Known as “blood sug­ar”, glu­cose de­liv­ers fuel to the or­gans, while galac­tose op­ti­mizes the work of the im­mune sys­tem and brain. How­ev­er, it takes a lot of ef­fort to lure out these sug­ars from lac­tose and make them work for some­one’s ben­e­fit… Gen­er­al­ly, this process re­quires two com­po­nents - wa­ter and lac­tase. And you are right, “lac­tase” is only one let­ter apart from ‘lac­tose”! But, un­like galac­tose and glu­cose, those are com­plete­ly dif­fer­ent char­ac­ters. Just take a glance at the chem­i­cal por­traits of lac­tose and lac­tase to see if that’s true.

First of all, lac­tase is not a sug­ar - it is a di­ges­tive en­zyme that is nat­u­ral­ly pro­duced by the cells and bac­te­ria in the small in­tes­tine. In­struc­tions for mak­ing lac­tase are in our DNA – the LCT gene. If the LCT gene is "on", the en­zyme can be pro­duced in the cell. Then the en­zyme is free to go on to di­gest lac­tose.

How does it hap­pen?

The­o­ret­i­cal­ly, when you drink milk, wa­ter en­coun­ters lac­tose and at­tacks its galac­tose-glu­cose bond, adding an oxy­gen and a hy­dro­gen to the galac­tose, and a hy­dro­gen to the glu­cose. The fate of this fight is pre­dictable: milk sug­ar is sep­a­rat­ed into two sim­pler sug­ars, galac­tose and glu­cose.

This re­ac­tion is called hy­drol­y­sis, which sim­ply means “split­ting with wa­ter”. But with­out the as­sis­tance of lac­tase, this re­ac­tion would go very slow­ly, and the hu­man body wouldn’t be able to ab­sorb lac­tose by the time it reached the large in­tes­tine. And to think, al­most all hu­man ba­bies have enough lac­tase in their bod­ies to break down lac­tose. In fact, lac­tose pro­vides about 50 per­cent of their to­tal en­er­gy! As they grow up, the LCT gene be­comes less ac­tive and of­ten switch­es off. Then one day, un­aware of this change, the adults de­cide to treat them­selves to ice cream or a slice of cheese­cake and sud­den­ly ex­pe­ri­ence dis­com­fort… The ab­sence of lac­tase in their bod­ies makes lac­tose build up in their guts, where gut bac­te­ria eats it, pro­duc­ing gas, bloat­ing, stom­ach pain, di­ar­rhea and oth­er un­pleas­ant symp­toms.

Sur­pris­ing­ly, only about 35 per­cent of adults world­wide can bliss­ful­ly en­joy milk prod­ucts, while the rest lose the abil­i­ty to make lac­tase and be­come lac­tose-in­tol­er­ant. And some­thing is strik­ing about lac­tase's ge­og­ra­phy. Ap­par­ent­ly, peo­ple in north­ern Eu­rope and those from some African tribes make a lot of lac­tase even af­ter they are adults. From sur­vey­ing dif­fer­ent eth­nic groups, sci­en­tists have been able to link this abil­i­ty with the fact that those lucky pop­u­la­tions had tra­di­tion­al­ly herd­ed cows and oth­er milk-pro­duc­ing an­i­mals!

Since we are on the sub­ject, are all milks the same?

Per­haps the sci­en­tists of the Smith­so­ni­an's Na­tion­al Zoo in Wash­ing­ton, D.C. can help us to find the an­swer. This zoo has the largest col­lec­tion of milk sam­ples in the world. The sci­en­tists who study more than 16,000 kinds of milk pro­duced from over 200 species of mam­mals say that the tubes la­beled “hip­po”, “go­ril­la” and “African ele­phant” might fea­ture a sim­i­lar col­or, but they have very dif­fer­ent lev­els of fat, pro­tein, min­er­als and, of course, lac­tose. Milk sug­ar makes up about 1-8 per­cent of the solids in mam­mal’s milk. But the fat­ti­er the milk, the less lac­tose is in it. Thus, with 4.2 per­cent fat, hu­man milk con­tains 7.2 per­cent lac­tose, while hood­ed seal milk has 61 per­cent fat and no lac­tose at all! This con­trast shows that dif­fer­ent species have dif­fer­ent needs to sur­vive in their en­vi­ron­ments. And the sci­en­tists con­tin­ue their re­search to dis­cov­er new ways to save en­dan­gered species and also to study how hu­man milk evolved.

So, let’s say you know that milk is one of the best sources of cal­ci­um. And its de­riv­a­tives like yo­gurt and cheese are good for your bones, mus­cles, and nerves… How­ev­er, what if you love milk but can­not stand lac­tose? Af­ter all, lac­tose-free yo­gurt doesn’t taste the same… Here’s the good news: lac­tose in­tol­er­ance isn’t life-threat­en­ing. Un­like a milk al­ler­gy, when the body at­tacks it­self once it en­coun­ters any­thing with milk pro­tein, lac­tose in­tol­er­ance can be man­aged. While low-lac­tose or lac­tose-free foods are a good op­tion, some diet changes can en­able you to keep eat­ing and drink­ing real dairy! So it’s worth learn­ing which of the foods your body can or can­not tol­er­ate. Lac­tose obe­di­ent­ly dis­solves in wa­ter but gets stub­born to do the same in fats. Thus, while whole milk might be hard to di­gest, a piece of cheese to your sand­wich or a bowl of yo­gurt with fresh fruits are less like­ly to evoke any un­pleas­ant symp­toms. In ad­di­tion, some di­eti­tians rec­om­mend that you buy lac­tase en­zyme drops or cap­sules and take them be­fore eat­ing foods that con­tain lac­tose.

When you cre­ate a well-bal­anced diet and per­fect it, lac­tose be­comes your friend­ly sug­ar again. And you can en­joy lis­ten­ing to Cyn­di Lau­per’s song with­out any sen­ti­men­tal at­tach­ment to the lyrics.


  2. In the foot­steps of my lac­tose-in­tol­er­ant an­ces­tors
  3. In­side the world's largest col­lec­tion of an­i­mal milk
  5. Lac­tose
  6. Liv­ing with lac­tose in­tol­er­ance
  7. The sur­pris­ing links be­tween hu­man milk and the wild
  8. Lac­tose In­tol­er­ant Peo­ple May Soon Be Able to Eat "Real" Ice Cream Again
  9. What is the func­tion of lac­tose?
  10. What Are the Func­tions of a Hy­drol­y­sis Re­ac­tion in Bi­ol­o­gy?
  11. Lac­tose
  12. Химические свойства молока. Лактоза — Академия занимательных наук
  13. Ev­ery­thing about in­dus­tri­al lac­tose pow­der
  14. Sug­ar ex­plained
  15. Dif­fer­ence Be­tween Monosac­cha­rides Dis­ac­cha­rides and Polysac­cha­rides
  16. Lac­tose Some ba­sic prop­er­ties and char­ac­ter­is­tics
  17. Phys­i­cal and Chem­i­cal Prop­er­ties of Lac­tose
  18. Changes Dur­ing Lac­ta­tion In The Com­po­si­tion Of The Milk Of The African Black Rhi­noc­er­os
  19. Lac­tose: Prop­er­ties and Uses
  20. LCT gene
  21. What Are the Func­tions of Lac­tose?
  22. The Sci­ence Be­hind Lac­tose In­tol­er­ance
  23. 3 Rea­sons why Lac­tose is good for you
  24. Lac­tose in Phar­ma­ceu­ti­cal Ap­pli­ca­tions
  25. Lac­tose
  26. Lac­tose In­tol­er­ance
  27. Sev­en of the Most Ex­treme Milks in the An­i­mal King­dom
  28. Milk
  29. Life­style changes to make if you’re lac­tose in­tol­er­ant
  30. Sources of the Lac­tase En­zyme
  31. Молочный сахар
  32. Why lac­tose in­tol­er­ant peo­ple DGAF about avoid­ing cheese
  34. Milk as a Sports Drink
  35. 33 Celebs Re­veal What They Eat on Their Cheat Days