new world of flavors in them . You ’ ll slow down in general , allowing more time for your body to register that it is full . Moreover , chewing triggers the release of the hormone CCK ( cholecystokinin ) in the stomach , which signals ahead to the pancreas and gallbladder to get busy doing their work : Dinner is coming !
Down the Hatch
Once the food is pulverized , nice and moist ( another key role of saliva ), and ready to go , you swallow — it ’ s down the esophagus and into the stomach . This is a one-way ride , unless something is wrong and you have a condition like gastro esophageal reflux ( GERD ) and the esophageal sphincter relaxes too much , allowing food and acid to make an unwanted and unpleasant return .
The stomach works as an agitator to literally grind the food it takes in — it is composed of smooth muscle , built to churn . This mechanical action isn ’ t
as efficient or as effective as what the mouth can do , but so long as food is present , its muscular action is trying to break it down . Bigger hunks of food mean extra churning .
There ’ s help for this churning , of course . The stomach has lots of chemical allies , chief among them hydrochloric acid , or HCl . If you made it through seventh-grade chemistry class , you might remember this one : It ’ s pretty brutal stuff , eats through ( almost ) anything , and can be problematic if you spill it where it ’ s not supposed to go ( like onto your jeans or into the esophagus ). In the stomach , if everything is going according to plan , the HCl is working to break food down into its tiniest particles and is killing any microorganisms that might have hitched a ride in on the food . HCl levels naturally decline as you age , unfortunately , leaving a little more work for the rest of the system to handle . If you suffer from GERD or gastric ulcers , a painful defect in the stomach lining , you may be prescribed acid-suppressing medications such as protonpump inhibitors ( Zegerid , Nexium , Prilosec ) or histamine-2-receptor antagonists ( Zantac , Axid , Tagamet ). If you take them , your symptoms will be relieved , but HCl levels will be suppressed ,
“ paying forward ” a heavier load for the rest of the digestive system to handle and reducing absorption of nutrients that need acid to prepare them for absorption ( e . g ., calcium ).
Meanwhile , the stomach lining is busy , too . It ’ s producing the enzymes pepsin , which begins to cleave apart protein molecules , and gastrin , which stimulates the secretion of more HCl . It ’ s making mucin , which creates the mucous layer that protects the stomach lining from all that corrosive HCl . And it ’ s triggering the release of the hormone leptin , which reduces appetite and acts as an antagonist to the appetite-promoting hormone ghrelin .
Assimilation Assignation
If all has gone well and the stomach has done its job , it moves the food in a ( hopefully ) gruel-like pulp called chyme through the valve at the bottom of the stomach ( the pyloric valve ) into the
“ you cannot help but be amazed at how magnificently the body has been designed in harmony with the natural world ”
duodenum . The duodenum is the first part ( about 12 inches ) of the small intestine , a small organ unto itself , with an incredibly important job .
As chyme moves into the duodenum , the pancreas and gallbladder come into play — and digestion begins to overlap with assimilation . Most people think of the pancreas as the organ that produces insulin to handle our blood sugar , but that endocrine function is only half its job . Its other function , called exocrine , is producing the chemicals the duodenum needs to function properly . Perhaps first and foremost , the pancreas releases sodium bicarbonate ( or bicarb ), which neutralizes stomach acid . In the alkaline environment of the duodenum , the pancreas ’ s enzymes can then take over . Along with bicarb , the pancreas releases into the duodenum a host of enzymes , primary among which are amylase , which further breaks down carbohydrates ; lipase , which breaks down fats ; and trypsin , which breaks down proteins . Meanwhile , the gallbladder also squirts some bile , an alkaline greenish-brown fluid produced by the liver , into the duodenum to assist in the breakdown of fats ( and it also carries some detoxified fat soluble substances from the liver for elimination out the intestines ). Whereas
HCl acted as a machete to crudely hack apart hunks of food in the stomach , enzymes in the duodenum are more like scalpels , reducing food to its molecular components so that it can be absorbed in the small intestine . Vitamins , minerals , phytonutrients , amino acids , carbohydrates , fatty acids . . . all are released from the food and readied to be soaked in and used by the body .
Hopefully , you ’ ve chewed well and your stomach has had a chance to do its job perfectly ; if not , the duodenum will take up the slack . Here ’ s the rub : If larger chunks of food have gotten through , more enzymes and bile will be needed to process that food . That means more stress on the pancreas and ultimately the liver , which will kick up bile production and send it in via the gallbladder . Unfortunately , these two organs have other important jobs to do , namely regulating insulin ( pancreas ) and detoxifying the body ( liver ). Can you see how stressing the system day after day with unchewed , unprocessed , undigested food might result in some unpleasant side effects ? Once food moves out of the duodenum and into the rest of the 20 feet of small intestine , coaxed along via peristaltic waves ( rhythmic contractions of the smooth muscles ), the heavy work of digestion should have been done , and assimilation gets going . The design and function of the small intestine ( let ’ s call it SI ) is truly marvelous — you cannot help but be amazed at how magnificently the body has been designed in harmony with the natural world , and how , even amidst our best efforts to undermine it , it keeps on chugging to serve us ! To maximize the absorption area of the SI , it is lined with hundreds of thousands of small projections called villi , which also make a few more enzymes to further facilitate sugar breakdown . Here is where the most usable nutrition gets passed into the blood vessels through tightly packed cells ( epithelial tissue ) that line the villi , and what is not useful gets pushed on through the system and into the large intestine for disposal . The cells that line these villi are first of all guardians — they try to keep out anything harmful . In that way , they are the body ’ s first line of detoxification . Each of them has thousands of tiny channels that open and close to let in only selective nutrients that have been properly prepared . Between each cell , there is a tight junction that is meant to prevent leakage of anything into the body — specifically into the interstitial space behind the cells . This interstitial space is a soupy area where nutrients ( including oxygen ) come from the arterial capillaries to supply the cells . This is a heavy exchange zone , as processed toxins and other
10 • INSIDE HEALTH