Welcome to another installment of How the Body Works! This post is a basic overview of how the digestive system works. If you want more in-depth on specific digestion issues use the categories on the right-hand side of the page to choose "digestion" or "digestive disorders" for a complete listing of more detailed articles.

Digestion is the process by which the body breaks food down into a small enough and simple enough form that can be absorbed into the bloodstream. In a healthy person each bite of food is transformed into its tiniest molecular components.

The three basic categories of food are carbohydrate, fat and protein.  Many foods are combinations of these basic categories. For more detailed info on carbohydrates go here, for fat go here or here,  and for protein go here. 

The end goal of digestion is to provide fuel for the cells and to provide them with the basic building blocks to construct all of the different enzymes, hormones and other substances necessary for life and health.

We are commonly told that carbohydrates provide the main energy source for cells. This isn't quite true. Glucose - which is a very simple sugar - IS the fuel of choice for cells - BUT carbohydrates are not the only source for making glucose.  Our bodies are very good at making glucose. To quote Gary Taubes' book Good Calories Bad Calories "Though glucose is a primary fuel for the brain, it is not, however, the only fuel, and dietary carbohydrates are not the only source of that glucose..."  He goes on to explain how our liver synthesizes the amino acids in protein, or breaks down triglycerides and also uses special molecules called ketone bodies for cell fuel. Our bodies are very good at making glucose with or without eating sugary or starchy foods.

Even before the moment you take a bite, digestion begins. Seeing and smelling food cause enzymes to begin flowing, not only the salivea in your mouth, but also the stomach, pancreas and liver get revved up.

                        
 
Your teeth start the physical break down as they bit and chew into smaller and smaller pieces.  Enzymes in the saliva immediately start making chemical changes to any carbohydrates you chew.

Real foods (as opposed to "dead"/processed foods) also contain varying amounts of their own enzymes which assisst the body in digestion.  Raw milk, tropical fruits (pineapple, papaya, avocado, mango, banana), cultured & fermented foods (sauerkraut, yogurt) are especially high in important enzymes aiding digestion.

We swallow and food travels down the esophagus on to the stomach. The stomach is a very muscular bag that physically mashes teh food and churns it with powerful hydrochloric acid that breaks food down AND kills germs at the same time. Surprisingly, it is a LACK of stomach acid that causes heartburn/acid reflux. Learn more about that here.

Proteins begin their breakfdown in the stomach with help from enzymes produced in the pancreas.
                              
                                             source

Leaving the stomach, food travels into the small intestine where bile from the gallbladder and enzymes from the liver break down the fats and finish the break down of proteins. Very important specialized structures in the small intestine produce millions of tiny VILLI.  The VILLI line the entire length of the small intestine. Healthy VILLI have long wavy hairlike things that grab hold of the food molecules and transport them safely to the blood cells.

                          

Also important in digestion are the trillions of beneficial bacteria that live in the intestine.  They play a vital role in breaking food into digestible pieces, plus they make some key nutrients themselves.  They also help to nurture the hairy VILLI keeping them healthy and fully functioning.  Toxins in our food and from bad bacteria and antibiotics can upset the balance of good bacteria and injure or even kill the VILLI.  As you can guess, this makes for all kinds of problems. These problems are as varied as ADD, allergies, asthma or even Crohn's, chronic fatigue and much more. An in-depth look at VILLI and related issues can be found in Gut And Psychology Syndrome.

Leaving the small intestine the unabsorbed leftovers move to the large intestine.  Here the body absorbs most of the water and minerals.  The rest is considered waste and passes into the rectum to be released.  10-20 hours is the time it takes for a healthy body to fully digest a meal. Excretion of waste should happen regularly about two to three times per day. If this isn't happening with you this is an indication of trouble somewhere in the digestive system. Are you nurturing your VILLI and your trillions of beneficial bacteria? Are you eating real food with plenty of enzymes? For more info on helping digestive disorders start here.

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A Chicken in Every Yard:The Urban Farm Store's Guide to Chicken Keeping
by Robert and Hannah Litt
Ten Speed Press 2011

                                       
                                                   source

One of these days we hope to be among the chicken-owning-cool-people crowd. Right now we're doing our homework, checking out books from the library, finding websites on coop designs, talking to friends who already own them.  My daughter has picked out names for each potential hen and written lists of favorite breeds. Of all the books I've read so far A Chicken in Every Yard wins the prize for best overall beginner's guide. At just shy of 200 pages it isn't too long to be overwhelming, but it isn't too short to leave you with dozens more questions. The eight chapters cover everything from fuzzy chickie to omelet and include plenty of illustrations and photos.

Many chicken keeping books can name the different breeds and give you excellent reasons why backyard chickens will improve your soil fertility and help you grow toward self-sufficiency, but this book is the first one I've read that makes it all sound like so much fun!

                      

Backyard chickens can apparently also be sweet family pets if you treat them well and keep them well socialized with humans. But they will be more than pets. They are capable of so many helpful things. I'm interested in how they will bring greater fertility to my garden soil through composting their droppings. I'm also eager to let them eat the pesky bugs in my lawn and garden. I want my children to have the experience of raising farm animals. But most of all I want to be able to go outside in the morning and gather still-warm eggs for my breakfast, break one open to see the bright orange yolk and know that this is the freshest, most local food possible!

Robert and Hannah Litt have been raising backyard chickens for years and have turned a hobby into a business with their Urban Farm Store in Portland, OR. They've poured their knowledge and experience into this book. Each chapter contains personal insights such as this one on the Ameraucana breed "The staff at the store have voted this the most underrated breed. We always suggest including this bird even if you are getting only a few chicks. The egg color alone would recommend it, but the personality is the icing on the cake."

                                 

They walk you through selection of your birds, what to do when you bring them home, how to successfully care for them from tiny chick to full-grown layer, and what to do if a hen gets sick. There are designs and instructions for making your own coop and resources in the back for ordering them if you don't want to make one. Predators are addressed as are common ailments. The last chapter includes some of Robert and Hannah's favorite egg recipes.

After reading this book I feel much more confident in my ability to successfully raise a handful of chicks into a tiny backyard egg-laying flock.

                      

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Wanted: Critical Thinkers!

Lack of integrity in big industry, shareholder fortunes at stake, multi-billion dollar advertising budgets, government certifications and approval, research grants....and the list goes on and on.
There are so many reasons why we need to be critical thinkers and not just believe everything we hear, every study we read, every expert who testifies.

There are two sides to every issue. The side that "wins" may not always be the correct or accurate or truthful one. It may just be the one that yells loudest. That's how the cholesterol lipid hypothesis found its way into the McGovern Report years ago and became widely accepted despite lack of indisputable evidence.
 
I so admire Denise Minger and her ability to deconstruct complicated scientific data. Though I dont have that talent I have been honing my own critical thinking skills. In fact, while looking up something else recently I came across a study whose headline caused my "spidey sense" to tingle:
Weight gain in children has no association with sugar-sweetened beverage consumption
"An analysis of 12 recent studies indicate that there is virtually no link between the consumption of sugar-sweetened beverages and weight gain in children and teens. The meta-analysis is published in the June (2008) issue of the American Journal of Clinical Nutrition."source
"My co-authors and I carefully analyzed 12 studies using scientifically validated methods and found that there is virtually no association between sugar-sweetened beverage consumption and weight gain in children and teens," Dr. Maureen Storey said. "In fact, the evidence strongly suggests that reducing or eliminating sugar-sweetened beverages would have almost no impact on children and teens weight." Dr. Storey goes on to claim, "Sugar-sweetened beverages are a source of energy and energy consumption in excess of energy expended will lead to weight gain." 

"How can this be?" I asked myself.

 It was easy enough to find another study that said the opposite.
 
"A child’s risk for obesity increases an average of 60 percent with every additional daily serving of soda."
 That was the conclusion of a study titled "Relationship between consumption of sugar-sweetened drinks and childhood obesity: a prospective, observational analysis" published in Lancet, 2001 (357:505-508) by Dr. David S. Ludwig, et al.

So how do you explain two studies with two completely opposite conclusions? 

Enter: Critical Thinking Skills.  What things cause people to falsify data, provide incorrect conclusions or otherwise manipulate study results? Top of the list would be monetary gain followed closely by notoriety.  Which of these two studies can be called into question just by following the money trail?  The answer was frightfully easy - a few more clicks through Bing and I had it.
 
Dr. Storey's research was conducted at the Center for Food, Nutrition and Agricultural Policy at the University of Maryland. Yet less than a year later we find that she is "no longer in academia."source Where did she go? She got a job with the American Beverage Association. Yep, the soft-drink industry lobby became her new boss and her new title? Senior Vice President of Science Policy. She was still churning out the pseudo-science as you can see in her "analysis" of several hypertension studies that dared to suggest drinking sodas and other sugar sweetened beverages can bring about poor health.

In the interest of fairness I also followed Dr. Ludwig's trail. It turned out to be a short one - he's been employed for at least ten years by the Boston Children's Hospital as a Professor of Pediatrics where he's done study after study showing things like how dairy consumption actually helps people overcome insulin resistance, and how low-fat diets don't work for weight reduction in children.  

It took me about two hours to track down all of this information.  I didn't need fancy passwords or insider tips, it is all available to the public if you have the time to look for it.

I encourage you to grow your critical thinking skills. A great starter book that helps you sift through the fallacies in ad campaigns, scientific studies and political candidate claims is The Art of Argument by Hodge, Perrin and Larsen. It's a fun book and makes a great read-aloud with your kids so you can all grow better at spotting the fallacies and finding the truth.

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Biology is the focus of our homeschool science curriculum this year. We've covered plants and animals and now we are taking an in-depth look at the human body. The core text we are using is Scholastic's The Body Book: Easy-to-make Hands On Models That Teach by Silver and Wynne.
  
                                                          
                                                     The Body Book

Our lesson on bones, complete with paper models that move, provide a great springboard for slipping in lessons about nutrition and health. 

Did you know that our bones are not merely for structural support? Bones are useful in their role as skeleton, but they do so much more.  The familiar hard layer of bone is covered by a tough outer membrane. The hard layer is not solid, however, it is full of tubes or canals. Blood vessels and nerves penetrate through these canals to deliver nutrients and oxygen to the bone cells and carry away wastes and other surprising substances. 

Our bones make up 18% of our total body weight.  They are actually important "factories" which produce many important substances.  90% of the calcium and phosphorus in our bodies is stored within our bones, but it doesn't stay there. These minerals come and go as our bodies need them to perform other functions. In addition to strong bones and teeth, calcium is important in blood clotting, sending and receiving nerve signals, squeezing and releasing muscles, normal heartbeat and the releasing of hormones. We need calcium all the time, even when we aren't actively eating it, so our bones become the warehouse for calcium so it is always available.

                                       

Beneath the hard layer of compact bone lies the spongy area where some amazing things are produced.  Areas of red marrow are hard at work producing red blood cells and white blood cells. In babies all the bones contain red marrow, but by the time we reach adulthood only the very long bones in our arms and legs plus our skull bones still contain this red marrow. Billions of red blood cells leave the red marrow on a daily basis to replace the worn-out red blood cells in our bodies. The center area of the bone contains the yellow marrow as well as important fat that is used as a storehouse for the fat soluble vitamins needed by the bones as they manufacture these many important substances.  The yellow marrow can also convert into red marrow during times when extra production of red and white blood cells are needed.

                          

As children grow from babies into adults their bones require some very specific nutrients in order to fully and adequately lengthen, thicken and strengthen throughout the body.  A lack of adequate nutrition during this period of rapid growth will result in many different kinds of deformities and disorders. Since we're focusing only on bones today I will not list the other areas affected, but there is one place where a child's bone structure, and therefore nutritional health, can easily and accurately be illustrated: their teeth!

We are all familiar with the need for adequate calcium and phosphorus to build strong bones. Did you know that vitamins D, C and K are also necessary?  Possibly you may have never even heard about vitamin K since it is one of the newest vitamins to be identified within the last decade or so.  A very smart doctor back in the 1930's figured out this then unnamed vitamin played a crucial role in growth, development and long-term health. This doctor was the dentist Weston A. Price.  In his personal experiments and writings he called this vitamin "Activator X" because without it the other vitamins and minerals would not become fully "activated" to give superior growth and health to children and adults. 

                               
                                 Dr. Weston Price studied traditional diets 

Dr. Price realized this "activator X" worked synergistically with other wholesome, traditional, nutrient-dense foods to produce healthy, structurally sound children and adults. Without adequate amounts of these nutrient-rich foods, as seen when the people substituted white flour, white sugar and canned milk for their native foods, the children and adults suffered from poor health which was most apparent in their crooked and decaying teeth.

Vitamin K (K1 and K2) may be newly identified but it has always been necessary for good health. Especially important for humans is the form vitamin K2.  This vitamin is necessary for the proper utilization of calcium and phosphorus. Without adequate amounts available our bodies will deposit the calcium in our soft tissues and arteries instead of our bones and teeth. Often elderly women taking calcium supplements but NOT eating K2 will have x-rays that reveal bones as soft as rubber while their arteries are heavy and dark with calcium. 

K1 is found in great quantities in the rapidly growing green grass of spring and fall. It is no surprise that Dr. Price found his "activator X" in great quantities in the butter from grassfed herbivores such as cows, goats and water buffalo.  It is also found in fermented foods like kefir, yogurt, natto and sauerkraut. Our bodies can also manufacture a form of vitamin K within a healthy digestive tract that is well populated by beneficial probiotic colonies.

                               

If you would like to learn more about what it takes to truly nourish your growing children please contact us using our Well Fed Family CONTACT information at the bottom of the About Us page, or by visiting us at the Well Fed Family Facebook page and leaving a comment there. For those in Central Florida we offer several classes, many of which are free, to teach you and your friends about important nutritional considerations. 

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