Part of an occasional series on vitamins and minerals.
Zinc is sometimes called the “essential toxin”. Unlike other metals such as arsenic, cadmium and mercury, zinc is not only beneficial but also essential for the body to function properly.
Zinc is found in every cell in the body working behind the scenes to keep it functioning normally. In particular zinc helps enzymes to do their job.
What does zinc do in the body?
Some of the functions include:
Skin repair and preventing acne, mouth ulcers and stretch marks
Creating healthy sperm
Normal fetal development
Preventing macular degeneration (an aging related vision disorder
Zinc also plays a vital role in:
Appetite and taste
Carbohydrate and protein metabolism
Histamine formation (allergies)
Preventing hair loss and premature graying
T3 conversion (in hypothyroidism)
Preventing PMS, depression, jiggling feet and tooth decay
Zinc in food
Like another essential mineral iron, animal sources of zinc are better absorbed than the vegetarian ones. Good sources include red meat, shellfish (oysters being the most famous) and herrings.
There is also zinc in leafy greens, nuts, mushrooms onions and wholegrains. Other than the bioabsorption issue, the actual zinc content in the soil the plant is grown in can influence the mineral level of the food.
But that is only the beginning of the zinc status equation. Like other nutrients, how much zinc we absorb, require and are able to involves a complex web of co-factors.
To absorb zinc from food and supplements we also need adequate amounts of protein, B6 and vitamin D. Considering most Australians are low in vitamin D this could be a major co-factor in our zinc status.
Other than the co-nutrient and soil deficiency issues, zinc uptake can be impaired by too much calcium (e.g. in dairy products), phosphate (high in meat and carbonated drinks), phytates (in some vegetables and grains) or sugar in our diet. How we prepare our zinc rich food can also be a problem, refining grains such as turning them into flour or freezing vegetables reduces the mineral levels but so too can merely cooking our food.
We sweat out and urinate zinc, so things that increase these actions such as drinking coffee, alcohol, taking diuretics or even exercise can deplete us. Digestive issues that may result in malabsorption problems such as diarrhoea, Crohns or uncontrolled celiac disease will result in zinc loss.
Common medications including the contraceptive pill, oestrogen replacement, ACE inhibitors (for high blood pressure, antibiotics and steroids can reduce our levels, so can stress or surgery.
How do you know if you are low in zinc?
While simple signs like having rough skin, white spots on your nails or thinking food doesn’t taste right may indicate you need more zinc, sometimes the symptoms are not as obvious or more complex, such as feeling depressed or having food allergies.
Many naturopaths use a special zinc liquid that may indicate your zinc status. When you are low in zinc the liquid has no taste, when your status is good a strong flavour is noticeable. While this is not infallible, it can be a good place to start.
Other than increasing zinc through food and supplements, it is important to work out why you are low in this essential mineral in the first place. I tend to find if you are low in zinc you are likely to be low in other nutrients as well, so a full review of diet, lifestyle and medications might hold the key.
For example – a teenager with acne may be drinking lots of milk or is a vegetarian, which could impact on their zinc status. A common treatment for acne is long-term antibiotics and that may further reduce zinc levels and prolong the acne.
There are lots of different types of supplemental forms of zinc available. The better absorbed forms include zinc sulphate, gluconate, chelate or orotate.
Another confusing aspect of supplementation is the term “elemental zinc”. The packaging should supply the type of zinc, how many milligrams (mg) there are but also what that dosage is equivalent to in “elemental zinc”. Use the amount of elemental zinc to guide your dose.
Adults low in zinc should take between 20-30 mg/day of elemental zinc.
This is particularly important in preconception for men and women and during pregnancy if vegetarian.
Long-term zinc supplementation, if not in a balanced complex, may disrupt levels other nutrients (such as copper). It is more important to address the reasons why your levels are low and rule out factors that may be blocking zinc absorption and utilization.
The podcast for this show is now available online (thanks Barb for your speedy work!). You can also subscribe to the Health Trip podcasts through iTunes, if you don’t know how to do that this link will help.
Is zinc a toxin? Science buffs might like to read this article:
The Essential Toxin: Impact of Zinc on Human Health
Laura M. Plum , Lothar Rink and Hajo Haase
Int. J. Environ. Res. Public Health 2010, 7(4), 1342-1365; doi:10.3390/ijerph7041342