Sunday, February 19, 2012

Intermittent Thoughts on Insulin Resistance: Episode I of the "Insulin Resistance Saga" - Non-Alcoholic Fatty Liver Disease Lurks on Your Way to the Kindergarten

Image 1: Map with the 2007 Rates of Overweight and Obese Children in the USA. With a childhood obesity rate of 44.4% Mississipi is the uncontested no.1 (source NCSL)
When we look back at the last installment of the Intermittent Thoughts the maybe surprising, maybe foreseeable end of the "Insulin Resistance Saga" was that that our protagonist, the human body ended up in a state, in which its cells are starving - and that despite exogenous, as well as as endogenous overabundance of energy in form of readily available calorically dense food (exogenous) and body fat stores that are bursting at the seams... but was it really Granny's pie that is to blame for all of that? Or was not enough exercise, after all? I guess to answer these and other questions and to get a little more insight into what people like to call the etiology of something - in this case, obviously insulin resistance and the obesity epidemic - we will have to go back, way back in time...

Flashback to Episode I of the "Insulin Resistance Saga"

Since, I do not want you to be mad at your parents we will start with the moment you are born and just assume for the time being that your parents have "done everything right" (whatever that may mean) and did not provide you with an epigenetic headstart on your way to being an obese type II diabetic. Let's further assume that your mother has the providence to not even think about feeding you "formula" (let alone soy based one) and that you are growing and developing marvelously (the speed at which babies develop during their first months on earth is by the way indeed "marvelous"), until... well, until your mother either decides or, out of financial reasons, simply has to start to work again. Suddenly, you, who was the center of (at least) your mother's world for the past couple of months, now have to be "managed" around working hours (or other obligations). That does not only take time, it will also drain on your mother's strength, who will have to ramp up her cortisol levels to reconcile her little bugger, her job, the household and all the other things mothers have to do... stress!

Image 2: 88% of all working parents suffer stress related health problems (workingmomsbreak. 2011). Now, guess what happens to their children? (img
No matter how good your beloved mother may be at doing this, the mere increase in cortisol levels, which, contrary to common believes, helps not hinders her cope with all these stressors will have an impact on the programming of your pituary-adrenal axes. In October 2002, Essex et al. published the results of a large scale longitudinal trial (this is a trial, where you follow your subjects from T1 to T2 instead of probing different subjects at T1) in which they analyzed salivary cortisol levels of 282 4.5 year-olds and 154 of their siblings for correlations between contemporary cortisol response of the pre-schoolers and maternal reports of stress that had been obtained, when the children were 1, 4, and 12 months old (Essex. 2002), the results are unequivocal: "Concurrently stressed children with elevated cortisol also had a history of high maternal stress exposure in infancy."

Setting the stage for "post saber-tooth tiger flight-response candy-binges"

Now, that alone would not really be a problem. After all, we have seen in the first installment of this part of the Intermittent Thoughts (cf. "The Marathon Paradox") that the dreaded "stress-hormone" cortisol, can actually be your best friend, if you have good physical reasons for being stressed. Nowadays, the chance of being chased by a saber-tooth tiger has yet become infinitesimally small. The number of opportunities for  post saber-tooth tiger flight-response candy-binges, on the other hand, are ubiquitous - even for you as a 4-year old pre-schooler, who has been conditioned to quench his thirst for stress-relieving affection with the sugary infant "teas" and juices, your mother found worked so wonderfully to calm you down, whenever you were crying.

Now that you are sitting at the table, spooning a tiny portion of stress-relieving sugar sweetened, chocolate coated healthy whole-grain cereals from a puddle of the almost transparent fat-free milk, you obviously cannot remember those episodes anymore. "Hmm... those ChocoHealthyGrinyPops are great! Can't believe they are good for my health, as well. Awesome!" As the glucose from your "breakfast" hits your bloodstream, your mother who has justed wrapped your peanut butter sandwich into one a bisphenol-A laden plastic wrap to put it with one of the healthy no-fat cereal bars she has bought for you into a multicolored lunchbox (made in China - and I guess you know what that means ;-) is already urging you to go - after all "Mummy must not be late, sweetheart!"

You are one out of ten! The one with beginning non-alcoholic fatty liver disease.

Image 3: In a society where only poor people walk, "lack of exercise" is a downright understatement.
On your 5 min car ride to school, your body, who obviously does not know that there is no saber-tooth tiger waiting for you in the Kindergarten, makes sure to convert as much of the incoming sugar into triglycerides to stash it away in your yet easily expandable fat stores - just in case, you never know... Meanwhile, you are looking out of the window: Kevin another kid from the Kindergarten is walking at his mother's hand... "Poor sobs, can't afford a car!", is what you are thinking, while your liver struggles with the incessant influx of fructose. As in 10% of all children in the industrialized countries (Nomura. 2012), some of the glycerol-bound fatty acids your liver is producing day in and day out from the high fructose-corn syrup laden foods, which are always there for you, when you need them, have gotten stuck somewhere in the red-brownish organ, the existence of which we usually only notice, when it's already to late.

In a way you are lucky. You are, as of yet (!), only in stage one of a (in most cases) reversible process of ongoing steatosis. You are yawning, when your mother opens the door and says: "I told you, you would be tired... but no, you had to watch yet another show on the Kid's Channel. Here, take a sip from the refreshing apple juice I have filled into your drinking bottle. It is the sweet one, you like so much!" You grab your bag and the neon green bottle, in which the acid fruit juice is just about to dissolve the last rest of BPA from its polycarbonate plastic walls, and try to avoid the kiss your mother is trying to give you... damn! Too late.

[to be continued... after another 6-days science break ;-]