IMPORTANT: The information on this site should never be used to self medicate or to self diagnose. Always contact your health care provider before using any kind of supplementation or making any extreme change in diet.
WHAT IS ZINC?
Zinc (Zn) is a metallic chemical element with the atomic number 30. It is also known as ‘spelter’.
Zinc is an essential trace element and is extremely important to human health and the only metal that appears in all classes of enzymes.
Our bodies usually have from two to four grams of zinc residing in our brains, muscles, bones, kidneys, liver and with high concentrations in our eyes and, in men, the prostate. Zinc is very important to the functioning of the prostate gland and to the growth of reproductive organs.
WHAT DOES ZINC DO FOR US?
Zinc plays a role in a whole range of cellular and metabolic activities in our bodies.
The Linus Pauling Institute outlines three ways in which the cells use zinc to function:
Enzymes are how our bodies create or catalyze new molecules. Close to 100 of these depend on zinc to execute these activities.
Both proteins and cell membranes need zinc to maintain their structure. The ‘zinc finger motif’ is used by many proteins to maintain their structure. Zinc deficiency increases the chances of damage from free radicals because the cells membrane becomes damaged and allows unwanted activity.
(Zinc fingers consist of one or more zinc ions that stabilize certain protein structures particularly in the binding of molecules in DNA and RNA.)
a. Zinc fingers are part of proteins that can regulate gene expression by attaching to our DNA and influencing the way the information from our genes is copied. In other words they act as ‘transcription factors’, copying DNA information for replication.
b. Zinc is involved in cell signaling. Both hormone release and the transmission of our nerve impulses are influenced by zinc. Cells in the prostate, immune system, salivary glands and the intestines use zinc to communicate with other cells in our bodies.
c. New cells are created regularly in our bodies and old cells die off.
The process of this cell death is directed by our genes and is called apoptosis. Zinc plays a role in this process. This process of creating new cells and apoptosis is very necessary to proper growth and maintenance of our bodies and poorly orchestrated cell death is implicated in diseases such as cancer.
WHAT HAPPENS WHEN WE DON’T GET ENOUGH ZINC?
Lack of zinc in our diet is what usually causes zinc deficiency. However, problems with absorption can also cause problems. Liver disease, diabetes, cancer, sickle cell anemia and other chronic problems can inhibit zinc absorption. Supplemental iron can impede the absorption of zinc but this does not happen with dietary iron.
Calcium in large amounts from the diet reduces zinc absorption in post menopausal women but not in premenopausal women or girls. Supplemental calcium or foods high in lime (calcium oxide), however, can cause malabsorption.
There is a disease called acrodermatitis enteropathica which is a genetic disorder that impairs the bodies ability to absorb and use zinc.
Too much or too little zinc can depress the immune system. Mild zinc deficiency can create a whole host of problems. Reproductive problems, problems with sexual maturation, poor appetite, lesions in the skin and in the eyes and problems metabolizing carbohydrates are some of the symptoms of low levels of zinc in the human body.
Severe zinc deficiency will lead to conditions such as severe and chronic diarrhea, poor wound healing behavioural problems and night blindness. Night blindness because zinc is part of retinol-binding protein which is necessary for vitamin A production and utilization and vitamin A is necessary for the production of the protein called rhodopsin that helps us see in the dark.
WHAT HAPPENS WHEN WE GET TOO MUCH ZINC?
Too little zinc is a bad thing and too much zinc is a bad thing. Too much zinc decreases copper and iron absorption. In fact decreased copper absorption can happen at levels as low as 60 mg of zinc a day. Copper deficiency is the most worrisome of excessive long term high zinc supplementation combined with dietary sources. Over 50 mg of zinc per day over extended periods of time increases the creation of a protein called metallothionein which binds metals and prevents them from being absorbed into the body. This protein binds copper and produces a copper deficiency. See the post on copper for ‘what happens when we don’t get enough’ copper.
Galvanized containers can release zinc into their contents and people who consume food or beverages that have been exposed to these contents can reach toxic zinc levels resulting in vomiting, diarrhea and abdominal pain. Inhalation of zinc oxide from industrial use can produces weakness, rapid breathing and excessive sweating that can persist for up to a day after there is no longer any exposure.
WHERE DO WE GET ZINC?