Download Micronutrient essay1

Morgan Gay
3538885
Absorption of nutrients is vital for a life of good health. Micronutrients in particular are
somewhat of a menace when it comes to absorption. A micronutrient is any vitamin or
mineral. There are many characteristics in each micronutrient that either inhibit or
promote absorption of the nutrient. This paper will discuss what could inhibit or promote
absorption of the micronutrients necessary for a life of good health.
A chelator is a complex molecule that will combine with a less complex molecule to
promote or inhibit absorption of the nutrient. A weak chelator (e.g. citric acid, gluconic
acid, acetic acid, malic acid, hydrochloric acid, Vitamin C, free amino acids, and fermentable
fibers) promotes absorption of a nutrient and a strong chelator (e.g. nonfermentable fibers,
caffeine, alcohol, phytates, oxalates, and tannins) inhibits it.
Another important factor effecting absorption is age. The older a person is, the less
hydrochloric acid (HCl) he/she will have in his/her stomach. HCl is important because it
will cleave the protein from Vitamin B12. In the stomach, the B12 affiliates with RProtein and
Intrinsic Factor (IF). However, RProtein and IF do not break Vitamin B12 down in the
stomach. Once the B12 enters the small intestine, the RProtein is cleaved off by pancreatic
proteases. Then in the ileum, a receptor binds the IF to the B12 , which is then absorbed in
the ileum. However, if HCl is absent, none of this can occur and protein and/or B12 will not
be absorbed.
Bile acids and salts are extremely important in the absorption of fat and fat-soluble
vitamins. They act as detergents to emulsify the lipids and fat-soluble vitamins. Micelles are
formed by bile acids and salts. Micelles are like boats that carry the fats to the brush border
enzyme where fat is dropped off and absorbed into the enterocyte, then formed into a
chylomicron and released into the lymph system. Resin-type drugs and phytostanols
inhibit the absorption of cholesterol by binding the bile so it is excreted in the feces.
Intake of certain minerals with other minerals can decrease their absorption. Some
will compete with other minerals for the same absorptive pathway. Iron and zinc share a
common absorptive pathway and when the ingestion of one mineral is commonly greater
than the other, there will likely be a deficiency of the mineral of smaller quanitity. Iron,
Morgan Gay
3538885
calcium, and zinc all decrease the absorption of copper. Zinc and copper act upon one
another. Large amounts of either mineral can cause a deficiency in the other.
Alcohol has the potential to prevent absorption of many B vitamins. Thiamin,
riboflavin, and folic acid are not absorbed in the presence of alcohol. Vitamin B6 absorption
is also greatly affected by excessive amounts of alcohol to the body. In the presence of
alcohol, PLP (an important B6 transporter) is broken down, thus the absorption of B6 is
inhibited.
Phytates, oxalates, and polyphenols all come from plants and all inhibit the
absorption of certain nutrients. Phytates decrease the absorption of a few nutrients
previously mentioned, such as calcium, iron, zinc, and copper. The phytates will bind to the
mineral and make it less available for absorption or will be excreted in the feces with the
nutrient attached. Oxalates work in the same manner as phytates; they bind to the
nutrients and are excreted. Oxalates inhibit absorption of iron, calcium, and zinc.
Polyphenols are found in high concentrations in tea and coffee. They inhibit the absorption
of iron by binding to it and which forces it to then be excreted because the body cannot
absorb polyphenols.
Cooking has influences on food that can inhibit or promote absorption of nutrients.
There is some good news. Cooking certain foods, for example, carrots, can help with the
absorption of carotenoids by making the bonds more accessible to the enzymes. Foods that
are high in thiaminases such as raw fish need to be cooked or the thiamin cannot be
absorbed. Cooking the fish inactivates the enzymes that are preventing thiamin from
absorption. Certain vitamins, such as C, B6, and folic acid, may be sacrificed in the cooking
process. However, cooking can make certain nutrients more bioavailable and can also
denature the proteins.
Absorption of vitamins and minerals are very important for many physiological
functions in the body. There are many things that can inhibit absorption, but there are also
many things that can promote it. Consuming a variety of foods increases the likelihood for
optimal micronutrient absorption. Balancing this scale of absorption and excretion is the
important, but most difficult, part of a healthy life of eating.