WHAT IS ZINC?
Zinc is a micromineral (or trace element) that is found mainly in high protein foods. It has a number of important roles in the body supporting proper metabolism and a strong immune system. In this article I will be providing you with a full breakdown of this important nutrient.
WHEN WAS ZINC DISCOVERED?
Awareness of zinc ores dates back many years. In Transylvania an alloy containing 87% zinc was found in prehistoric ruins. Objects made of brass (an alloy of copper and zinc) have also been discovered in Palestine and are thought to date back to around 1300 B.C.
Zinc was first isolated in the thirteenth century when a process was developed in India to extract this nutrient from its ores. The process involved heating zinc ore in a closed container. The heat would cause the zinc to evaporate and the vapours would then condense on the inside of the container as it cooled. Once the container had fully cooled the zinc could be scraped from the container and collected.
In 1526 the Swiss alchemist and physician Paracelsus wrote about some of zinc’s properties naming it “zincum”. Whilst Paracelsus admitted he did not know what the metal was made from he is credited with the discovery and naming of zinc.
In 1746 the German chemist Andreas Marggraf managed to isolate zinc by heating a mixture of calamine (a mixture containing zinc oxide) and charcoal in a closed container. Based on his work Marggraf is credited as being the first Westerner to isolate zinc.
HOW DOES YOUR BODY USE ZINC?
The human body contains around 2 to 3 grams (g) of zinc. Approximately 60% of this is stored in the muscles, 30% in the bones and 5% in the skin. The remaining 5% is distributed within the body’s other cells. Zinc has many roles in the body which include:
– Acting as an antioxidant to protect your body’s cells from oxygen related damage.
– Assisting in the healing of wounds.
– Assisting in the production of sperm.
– Maximising your cell’s sensitivity to insulin (making it particularly useful to diabetics).
– Maximising your metabolism.
– Possible protection from prostate cancer.
– Promoting improved brain function and memory.
– Promoting normal skeletal growth.
– Promoting proper taste and smell (by linking with the protein gustin).
– Protecting you from skin conditions (such as acne and eczema).
– Reading genetic instructions.
– Reducing stress levels.
– Supporting the production of thyroid hormones.
– Supporting the production of various types of white blood cells (including B cells, macrophages and T lymphocytes).
HOW MUCH ZINC DO YOU NEED?
Our requirement for zinc increases with age and is even greater amongst pregnant and lactating women. The recommended daily allowances (RDAs) for zinc were set by the Institute of Medicine at the National Academy of Sciences in 1999 and are outlined below in milligrams (mg):
– Children aged 0-6 months:- 2mg.
– Children aged 7-36 months:- 3mg.
– Children aged 4-8 years:- 5mg.
– Children aged 9-13 years:- 8mg.
– Men aged 14 years and older:- 11mg.
– Women aged 14 years and older:- 9mg.
– Pregnant women aged 18 years or younger:- 12mg.
– Pregnant women aged 19 years and older:- 11mg.
– Lactating women aged 18 years or younger:- 13mg.
– Lactating women aged 19 years and older:- 12mg.
WHICH FOODS CONTAIN ZINC?
As I mentioned at the beginning of this article, protein rich foods are the best source of zinc. However, certain plant foods also contain high levels of this nutrient. The list below contains six of the best zinc food sources:
– Cheddar Cheese:- 3.1mg per 100g.
– Oysters:- 90.8mg per 100g.
– Peanuts:- 6.6mg per 100g.
– Pumpkin Seeds:- 10mg per 100g.
– Roast Beef:- 10mg per 100g.
– Roast Lamb:- 4.1mg per 100g.
WHAT ARE THE SYMPTOMS OF GETTING TOO MUCH ZINC?
In 2000 the National Academy of Sciences established a tolerable upper limit for zinc of 40mg per day. It is difficult to consume this much zinc from food alone and the vast majority of overdoses are caused by zinc supplements. In situations where too much zinc is consumed it can lead to the following negative symptoms:
– Anemia (a low red blood cell count).
– Bitter or metallic taste in the mouth.
– Cramps.
– Diarrhea mixed with blood.
– Reduced absorption of copper, magnesium and iron.
– Nausea.
– Stomach pain.
– Vomiting.
WHAT ARE THE SYMPTOMS OF NOT GETTING ENOUGH ZINC?
Failing to consume adequate amounts of zinc is the most common cause of deficiency. However, bowel problems, chronic diarrhea and excessive sweating can also remove this nutrient from the body and lead to a deficiency. Certain antibiotics, high blood pressure medications and oral contraceptives can also interfere with zinc absorption. If zinc levels in the body do become low it can have a number of adverse effects which include:
– Depression.
– Diarrhea.
– Hair loss.
– Impaired growth and mental development in children.
– Impaired taste and smell.
– Increased susceptibility to infection.
– Poor appetite.
– Slow healing of wounds.
– Weak immune system.
ZINC SUMMARY
Zinc is an important nutrient that performs key roles throughout the body. If your diet contains adequate levels of protein then it is highly unlikely that you will experience zinc deficiency. However, if for some reason you consume very little protein then perhaps now is the time to make some changes to your diet.
What do you guys think? Were you aware of just how important zinc is in the body? Do you feel you are consuming enough of this important nutrient? Leave a comment and let me know.
Sources:
The Definitive Guide To Zinc
Top 10 Foods High in Zinc (HealthAliciousNess)
Zinc (Chemistry Explained)
Zinc (The Vegetarian Society)
Zinc (WH Foods)
Zinc (Wikipedia)