Like many supplements, zinc has several manifestations. For oral administration, zinc comes in the form of a salt called zinc sulfate. This form of zinc is likely effective in treating and preventing zinc deficiencies, treating Wilson's disease and reducing diarrhea in malnourished children, according to MedlinePlus.com. There is a potential that this form of zinc can also decrease the duration of cold and other infections, treat attention deficit-hyperactivity disorder, reduce the onset of age-related macular degeneration in combination with other supplements, mitigate osteoporosis and treat stomach ulcers.
Dosing Considerations
Zinc is a micronutrient, which means that the body requires it in relatively small proportions. Within the scope of appropriate dosages, zinc sulfate is not toxic. However, it is important to distinguish between zinc as a supplement and zinc as an element when selecting an appropriate dose.
For example, MedlinePlus.com recommends a 40 mg upper limit for elemental zinc. However, Zinc sulfate contains only 23 percent elemental zinc, so the recommended dosage for this supplement usually will be markedly higher than 40 mg. The recommended upper limit for zinc sulfate is 77 percent more than that of elemental zinc. Supplements usually suggest dosages specific to the type of zinc in that supplement, so ensure you review the label to verify that you're taking the appropriate amount advised by your doctor or nutritionist.
Toxicity
Zinc's toxicity becomes more evident as your consumption nears the recommended upper limit. Dosages at or exceeding 225 mg of zinc sulfate frequently causes vomiting, although gastrointestinal distress can begin after as little as 50 mg of zinc sulfate. Acute zinc toxicity results in diarrhea, nausea and abdominal pain in addition to vomiting. Ensure that you're aware of which supplement you have; zinc gluconate is a salt similar to zinc sulfate that likewise acts as a supplement, but its elemental zinc content is only 14 percent, or a little more than half that of zinc sulfate. Therefore, dosages of zinc gluconate will be significantly higher than those of zinc sulfate to obtain the same amount of zinc.
MedlinePlus.com also warns that taking at least 100 mg of elemental zinc daily -- which would be roughly 434 mg of zinc sulfate -- for a decade doubles the chance of developing prostate cancer.
Nutrient Interactions
Zinc can interact with other nutrients, a potential problem that worsens with greater dosages. Specifically, zinc hinders copper absorption, eventually resulting in a copper deficiency with extended inordinate use. Zinc also competes with folic acid, phytic acid, iron and chromium. On the other hand, calcium can prevent zinc absorption. Magnesium, riboflavin and manganese can improve zinc absorption -- the latter up to 50 percent.
Bottom Line
Zinc sulfate is not a toxic compound, but the elemental zinc it contains can be toxic in large enough doses. Although you can safely supplement dietary imbalances or treat various conditions using zinc sulfate, taking too much can cause greater health problems than your initial condition. Unless your doctor recommends or prescribes zinc sulfate for a specific condition, it is best to draw zinc from your diet. Foods that contain zinc include fruit yogurt, cheddar cheese, oysters, beef, pork, Dungeness craps, milk, almonds, cashews, almonds, turkey, peanuts, chickpeas and baked beans.
Member Comments