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NUTRIENTS – ABSORPTION AND ASSIMILATION
Whatever you eat is first digested, then absorbed, then assimilated in that order. Some
things are not digested or absorbed, such as fibre which serves as a chelator of toxins
(meaning that it fibre attaches itself to toxins and excretes them), providing bulk in the
elimination of waste from the body. Protein has virtually no fibre, and fat has none –
whereas carbohydrates contain both starch which is digested, and fibre which is not
digested.
Absorption happens when food is taken from the intestine into the blood, which delivers
it to the cells for assimilation. Digested molecules of food, water and minerals are
absorbed from the cavity of the upper part of the small intestine. The absorbed minerals
then cross the mucosa into the blood stream and are carried off to various parts of the
body for chemical change or storage. Each nutrient acts slightly differently, but this is
what happens in a nutshell.
By definition the assimilation of food is the act of becoming part of something greater in this case, the food is converted to become a part of you – it literally becomes your
body. Nutrients are incorporated into every cell of the body, feeding and repairing them.
Saliva begins the whole digestive process in the mouth in the case of carbohydrates,
and for this reason it‟s really important to chew your food well. Starches are digested in
several phases: an enzyme produced by our salivary glands first breaks them into
simpler molecules in the mouth. Juice produced by the pancreas takes it a step further
and finally the lining of the small intestine completes the digestion.
First the saliva and pancreatic juice breaks the molecules into maltose, then an enzyme
produced by the lining of the small intestine called maltase, splits the maltose into
glucose molecules which are then easily absorbed into the bloodstream. From here the
glucose is transported via the bloodstream to the liver for storage and energy.
When it comes to protein such as meat, eggs and even beans – we are talking about
extremely large molecules which must be fully digested before they are able to build and
repair the body‟s tissues. The first port of call for the protein‟s digestion is hydrochloric
acid produced by the stomach. Hereafter, the protein is transported to the small
intestine where many enzymes from pancreatic juice and the lining of the intestine
continue to break down these large molecules into much smaller ones, called amino
acids. In this state, the molecules can now be absorbed from the hollow of the small
intestine straight into the blood and carried to every part of the body. Protein is
absolutely vital for life as the building and repair process continues throughout our lives,
so this then is protein‟s primary function, as well as providing much needed nutrients
which we won‟t get from other foods.
Sugars are carbohydrates, as is the lactose in milk, and these need to undergo the
digestion process too in order to be absorbed. Milk needs the enzyme lactase found in
the intestinal lining to convert the lactose into absorbable molecules. Anything ending in
“ose” is a sugar such as maltose, sucrose, fructose etc.
Fat molecules are an outstanding energy source for the body, and going low-fat is
actually a mistake if you want plenty of energy. The idea is rather to have more of the
healthy fats and none of the damaged or useless (to the body) type of fats. With fats,
the body will first need to „dissolve‟ the molecules into a more watery kind of substance
in order to use them. Bile acids produced by the liver act as natural „detergents‟ if you
like, which dissolve fat in water allowing the enzymes to break the large fat molecules
into smaller ones – some of which are fatty acids and cholesterol. Dishwashing liquid is
a good example of how this happens – where the detergent breaks down the grease in
warm water, allowing the dishes to be cleaned. These bile acids unite with the fatty acids
and cholesterol, moving the molecules into the cells of mucosa. This is all part of the
process which allows fat to be absorbed by the body and used as energy.
Water and salt from the food and liquid we consume are absorbed from the small
intestine too - healthy adults absorb almost 4 litres of water containing about 30g salt
from the small intestine every 24 hours. The small intestine‟s main function is the
absorption of nutrients, water, fats etc.
Nutrient absorption is extremely important – nobody wants to miss out on getting all the
goodness needed to thrive – at any age – but there are ways to increase, or decrease
absorption and even interfere with the vital processes needed to ensure we get the
nutrition our bodies need. One such method of interference is regular antacid ingestion
– this will prevent the uptake of calcium, plus may decrease your body‟s ability to fully
metabolise protein. Antacids deplete not only calcium but folic acid and phosphorous –
both very important nutrients – while blood pressure medications deplete the body‟s
stores of coenzyme Q10, which may cause heart problems in time (especially if a statin
is also being taken at the same time).
Although medication is often necessary, and no medication should be discontinued
without your doctor‟s knowledge, one needs to be aware that all medication is going to
have some effect on nutrient absorption. Some severely deplete nutrient levels in the
body and doing „damage control‟ with extra nutritional supplements is a good idea in
order to offset these problems. Make sure you get a good brand of the nutrients you
need, and get them in bioavailable form for best results.
If you take oral contraceptives, you will find that you are depleting several really
important nutrients, namely folic acid, zinc, most of the B vitamins, vitamin C,
magnesium and selenium. Oestrogen-based hormone replacement therapy likewise
depletes most of the above, but in particular leaves you needing large doses of vitamin
B6 and magnesium. It‟s interesting to note that the stomach‟s ability to make
hydrochloric acid (HCL) for protein digestion is dependent on enough zinc and intrinsic
factor. If you have depleted your zinc stores, your HCL output may be insufficient and
your food will neither be digested properly nor absorbed and assimilated.
Some other medications which act like „nutrient-robbers‟ include antidepressants and
statins (for cholesterol lowering) both of which severely deplete coenzyme Q10 (an
“energy” nutrient). Antidepressants also deplete vitamin E and all the B vitamins notably B2, inositol and B6. Antibiotics on the other hand deplete intestinal flora which
lower immunity and upset the digestive system, and they likewise deplete B vitamins and
vitamin K. You can see how this will interfere with the body‟s ability to fully digest, absorb
and assimilate the food and nutritional supplements provided.
While we must certainly eat foods rich in these nutrients and diet is absolutely pivotal to
our state of health (after all – we are what we eat!), we know nutritional supplements
definitely play a powerful role. Ignore the slating of nutritional supplements due to
ignorance of current, cutting-edge research, and make sure that you are protecting your
precious body with good nutritional supplements. Not only are they a powerful form of
“medical insurance”, but you will feel so much better as you address your body‟s
deficiencies, and enable your body to make full use of the food provided – enhancing
digestion, absorption and assimilation of nutrients.