why can I eat cheese but not milk?

Lactose intolerance is very common.  In fact, 75% of the people world-wide have some degree of it.  However, as you may have noticed, some ethnic groups (Asians, African Americans, Native Americans, Ashkenazi Jews, and Latinos) are especially prone to it. Other risk factors include increased aging, premature birth, certain diseases affecting the small intestine (including bacterial overgrowth, celiac disease and Crohn's disease), and some cancer treatments. Lactose intolerance may also be a result of genetics (you are born without the lactase enzyme or born with an ineffective gene that has trouble producing the enzyme in sufficient quantities) or infections that injure the small intestine.

Lactose intolerance prevalence around the world

If you don't have lactose intolerance, let me tell you a little about what you are missing.  Lactose intolerance is essentially a condition that is characterized by the inability to digest the lactose in milk products (lactose is the sugar component of milk).  The symptoms of this include abdominal discomfort and other bowel related issues. (You do not want to sit on a plane next to someone who is lactose intolerant and just drank a few cups of milk!) Lactose intolerance is rarely serious, but can cause much discomfort.

The cause of lactose intolerance is the reduction or loss of lactase (the enzyme that is used to breakdown the lactose sugar into its subunits of glucose and galactose).  The unhydrolyzed lactose sugar remains in the gut and draws water to it (via osmosis) causing liquidy fecal contents to go through your system. (EW!) Additionally, the colonic bacteria naturally in your intestines ferment some of the remaining lactose, which leads to short chain fatty acid, carbon dioxide and hydrogen gas production that builds up and eventually needs to be released.

So, why can some dairy products be consumed more easily (and pain free) than others? 

thoughts about organics...

It has come to my attention that I've been slacking on my postings... for that I'm sorry.  It's been quite a busy semester.

Recently, we were asked to debate the pros and cons of organic farming.  I, as it turned out, was assigned to the con-side.  At first this seemed difficult because there really are many upsides to organic farming.  For one thing, organic farming tends to be more sustainable.  Organic farming uses natural fertilizers to promote the health of the soil, uses crop rotation, and limits the use of antibiotics, hormones, and genetically modified organisms (GMOs). This, arguably, reduces the impact on the environment and promotes a more nutritious product.  (There are less contaminants running from the soil into the water supply, contaminating other crops, and getting into the actual product).

Read more about organic farming.

However, as I found in my research, many organic practices have hidden costs.  It is more expensive for the farmer, consumer, and can negatively impact the environment.  Organic produce is, on average, 20% more than conventional produce (and can be up to 50% more).  With 48% of the population living on $2 a day, and about 13% living below the poverty line- does it make sense for everyone to buy organic?  There is an argument that organic produce is more nutritious than conventional; therefore, you are actually getting more for the increased price in terms of vitamins/minerals. However, there are studies that prove this, and studies that say that both products are equally nutritious.  I don't know what the answer really is!  But, sustainability and access to food is an important issue that is sometimes overlooked.  If food is too expensive, can we really ask/hope people buy it- even if it is "healthier"?