Sunday, November 7, 2010

Does Lactose Intolerance = No Cheese?

Dear Cheese Snob,

My doctor recently diagnosed me with Lactose Intolerance.  Does this mean I can't eat cheese? 

-Timmy Tummy-Ache


Dear Timmy,

Thanks for writing!  And I have good news for you: You can still eat cheese... just not all of them.

Before we get into which cheeses you can choose, let's talk about lactose.  Lactose is, simply, the naturally occurring sugars found in milk.  (The prefix "lact-" indicating milk; the suffix "-ose" designating a sugar.)  Lactose is a necessary component of milk that ensures the survival and growth of infant mammals.  Because the infant mammal gets all of its nutrients from drinking its mother's milk, it needs a substance with a high level of carbohydrates, and milk sugar fits that bill.

Lactase is an enzyme humans produce in their intestinal villi (villi are projections located in the small intestine that extend the surface area of the small intestine, allowing for greater absorption of nutrients) that allows for the proper digestion of lactose.  People with lactose-intolerance (or, hypolactasia) do not produce enough lactase in their intestinal villi to assimilate the lactose, and, as the beneficial bacteria in their intestines do their natural job of fermenting food for nutrient absorption, the fermentation of the (unabsorbed) lactose creates an overabundance of gas in the colon.  This gas causes a variety of symptoms in the hypolactasiac person, including diarrhea, flatulence, bloating, abdominal pain, nausea and acid reflux.

Most human infants produce enough lactase to drink their mother's milk, as well as milk from other mammals (cows, sheep, goats, et al); but, with age and/or decreased consumption, lactase production decreases, rendering the human lactose-intolerant.

In the cheese-making process, milk is fermented, just like it is in our small intestines.  By adding starter cultures -- beneficial bacteria such as Lactobacilli, Lactococci and Streptococci -- to the milk, fermentation occurs and the lactose is converted to lactic acid, a substance that has no ill effect on hypolactasiacs and is easily metabolized in the small intestine.  Starter cultures are generally used to make aged cheeses, not fresh ones.  And therein lies the rub: fresh cheeses are the ones hypolactasiacs must avoid.  Not only are starter cultures seldom used to make fresh cheeses, thus leaving much of the lactose intact, but fresh cheeses contain much more whey than aged cheeses, even cheeses only aged a short while, and whey is the enemy of the hypolactasiac. 

Whey contains lactose.  Whey is the liquid part of milk left over when milk is precipitated -- i.e. the curds are solidified and separated from the whey.  The curds are the solids, the proteins.

The rule for cheese is, the harder the cheese, the less moisture -- whey -- it contains; thus, the less lactose.  A harder cheese not only has been drained of its whey/lactose, but much of the lactose has already been converted to lactic acid during the beginning of the cheese-making process.

Okay, enough Dr. Science stuff.  Now I know I can eat some cheeses.  Which ones?

It depends on how lactose-intolerant you are, but a safe place to start would be with semi-firm or firm cheeses, such as aged cheddar, gruyere, Parmigiano-Reggiano, aged pecorinos, Swiss, etc. because most have absolutely no lactose.  If you find you can eat these cheeses with no ill effect, try a semi-soft cheese, such as taleggio, your favorite blue cheese, vacherin mont d'or, etc.  You might want to try the cheese in small amounts in the comfort of your own home, depending on the severity of your usual lactose-intolerant response.  Keep Lactaid on-hand, too, just in case.  I know it sounds a little pesky, having to conduct an experiment like this on yourself, but should you find you can eat a wider variety of cheeses, your quality of life will improve exponentially.

Most hypolactasiac folks can eat nearly any cheese with no discomfort.  Remember, the harder the cheese, the less lactose it has!

That sounds good!  Now, which cheeses should I avoid?

Nearly all fresh cheeses will upset your stomach.  You want to avoid mozzarella (fresh and "pizza" cheese), paneer, cottage cheese (which is basically curds and whey, Goldilocks), fresh ricotta, fromage frais and queso fresco.  Others can tolerate fresh cheeses as long as they are made with cultured milk; "culturing" is fermenting, converting enough lactose to lactic acid to render it safe for hypolactasiacs.  Quark is one example of a fresh cheese made with cultured milk.

If anyone out there is lactose-intolerant and has helpful tips to share, or names of cheeses they have been able to eat with no discomfort, please leave a comment and share with the class!