Zinc deficiency is common nowadays due to the fact that a lot of our soil is depleted of the minerals and nutrients it once had in abundance. According to a review by Wayne State University School of Medicine, “During the past 50 years, it has become apparent that deficiency of zinc in humans is prevalent. Nutritional deficiency of zinc may affect nearly 2 billion subjects in the developing world.”
So why is zinc so important?
It is needed in over 100 different enzymes and is likely involved in more bodily functions than any other single mineral. It really is a “Jack of all trades” and plays a role in immunity, male sexual function, growth and development of the body, maintenance of tissues, detoxification of toxins (both xenobiotic and endogenous) and much more.
What exactly does it do?
- Helps the Liver in detoxifying drinking alcohol, methanol, ethylene glycol and retinol (vitamin A) by being a part of the enzyme alcohol dehydrogenase.
- Utilizes and maintains levels of vitamin A in the body, which in turn helps to keep skin cells healthy and also generate new skin cells.
- Helps with the formation of collagen, which in turn speeds up healing from wounds.
- Is a co-factor for the enzyme, alkaline phosphatase, helping to place phosphate in bones.
- Plays a part in the structure of teeth and bones.
- Is most concentrated in the prostate and semen, contributing positively to male sexual function.
- Aids in the digestion of proteins by being a part of the digestive enzyme, carboxypeptidase.
- Plays a role in the synthesis of DNA and RNA.
- Has some antioxidant function by being a part of superoxide dismutase, which helps to protect cells from free radicals.
- Helps cell-mediated immunity by increasing production of T lymphocytes (white blood cells involved in immune response)
- Reduces the incidence of the severity of colds.
- Can help to balance hormones by the increasing of progesterone levels and lowering of estrogen levels in females.
Where can I find it in foods?
The best sources of Zinc are: oysters (10 X as much as any other food sources), red meats, liver, herring, egg yolks, milk products, and other poultry and fish.
Other, non-animal sources include: wheat, rye, oats, pecans, brazil nuts, pumpkin seeds, mushrooms and ginger root.
An important thing to note is that Zinc in animal foods seems to be better absorbed than from non-animal sources. One can still get enough zinc from whole grains and beans if they are prepared in a way that limits their phytate content (i.e. soaking). As stated in a review by Health Canada, “Zinc deficiency is most often found in countries where the primary source of protein is cereal grains. Zinc absorption from these grains may be limited by high phosphate and phytate content.”
Unfortunately, when foods are processed, much of the zinc is lost. According to Elson M Haas, MD and nutrition expert, approximately 80% of zinc is lost in the refining process of turning whole wheat into white flour.
How much do I need daily?
The minimum daily requirement for zinc is 8 mg for female adults and 11mg for male adults. It is estimated that most Americans get approximately 10 mg per day from food, but its likely that only 2-3 mg of it is actually absorbed. In the afore-mentioned review by Health Canada it states, “the fraction of zinc absorbed is difficult to determine because zinc is also secreted into the gut. Generally, 33 percent is accepted as the average zinc absorption in humans.”
If I don’t eat a lot of foods with zinc, is there a supplement I could take?
Yes! There are many zinc supplements out there. But before you land on one, it’s good to know about the different types. On each type of zinc supplement there will be listed the “total” zinc and the “elemental” zinc. The elemental zinc is what your body will actually be able to use so that is important to pay attention to. As you can see in the examples below from Boston University School of Medicine, there can be varying percentages of true zinc vs. elemental zinc:
ZINC PREPARATION : ELEMENTAL ZINC (MG):
Zinc acetate, 30% zinc, 25 mg 7.5
Zinc acetate, 30% zinc, 50 mg 15
Zinc gluconate, 14.3% zinc, 50 mg 7
Zinc gluconate, 14.3% zinc, 100 mg 14
Zinc sulfate, 23% zinc, 110 mg 25
Zinc sulfate, 23% zinc, 220 mg 50
Zinc oxide, 80% zinc, 100 mg 80
Some common types of zinc preparations include: zinc glycerinate, zinc acetate (used in cold lozenges), zinc picolinate, zinc orotate, zinc succinate and zinc citrate. these are all chelated with an amino acid or organic acid. One particular form that is known for its bio-availability and strong ability for absorption is zinc monomethionine. This form provides zinc that is bound up with the amino acid methionine, which is the most readily absorbed amino acid.
What other factors reduce zinc levels in the body?
Stress, burns, surgery and weight loss can all increase the loss of zinc in the body.
How do I know if I am deficient?
As a part of my training to become a Nutritional Therapy Practitioner, I learned to evaluate a client’s zinc status by performing the Zinc sulfate tally test. This is a very simple test where a measured amount of liquid zinc (as zinc sulphate heptahydrate) is held in the client’s mouth and analyzed for taste response. Those who are deficient will taste nothing at all, or perhaps even notice a sweet taste if particularly deficient. Those with adequate zinc status will notice a furry, metallic type of aftertaste; and those with good zinc status will immediately notice a very unpleasant taste. This test is very interesting due to the fact that zinc is one of the most important minerals in supporting our sense of taste to begin with.