Parasitic infections are common worldwide, affecting people of all ages and backgrounds. These infections are caused by parasites such as worms, protozoa, and insects that live on or inside the body and feed off the host. Some examples of common parasitic infections include giardia, cryptosporidium, pinworms, tapeworms, and scabies.
While there are many conventional medical treatments for parasites, there is growing interest in more natural remedies like dietary supplements. One supplement that has been studied for anti-parasitic effects is zinc. In this article, we’ll explore the evidence behind whether zinc can get rid of parasites.
How could zinc combat parasites?
Zinc is an essential mineral that is naturally found in many foods and available as a dietary supplement. It plays important roles in immune system function, growth, DNA and protein synthesis, and metabolizing nutrients.
When it comes to parasites, there are a few key mechanisms by which zinc could help fight these infections:
- Immune system support – Zinc is critical for development and activation of immune cells like T cells and neutrophils that identify and destroy invading pathogens.
- Disruption of parasite metabolism – Parasites have complex life cycles and zinc may interfere with their metabolism and growth.
- Increased intestinal wall integrity – Zinc improves the barrier function of the gut epithelium, preventing parasites from adhering and reducing diarrhea.
- Direct anti-parasitic effects – Test tube studies show zinc has direct toxic effects on the cells and metabolism of some parasites.
Through these mechanisms, zinc may be able to either kill parasites directly or improve the immune system’s ability to clear parasitic infections.
Does research show zinc is effective against parasites?
A number of clinical studies have investigated whether zinc supplements can treat parasitic infections, with mixed results:
Giardia
Giardia intestinalis is a common intestinal parasite that causes diarrhea. Several studies find:
- In Bangladeshi children with acute diarrhea and giardia, zinc supplementation for 6 weeks reduced giardia infection more than a placebo.
- In Vietnamese children ages 6 months – 5 years with persistent diarrhea and giardia, daily zinc for 6 months was more effective at clearing giardia than vitamin A supplementation.
- However, a study in Peru did not find a significant difference in giardia clearance between zinc and placebo in children with persistent diarrhea.
Overall, zinc seems to provide moderate benefits against giardia, especially in malnourished children.
Entamoeba histolytica
This parasite causes amoebic dysentery. Small clinical trials find:
- In Bangladeshi children with amoebic liver abscess, zinc supplementation increased the effectiveness of anti-amoebic drugs.
- In adults with intestinal amoebiasis, zinc supplementation improved symptoms and clearance of the parasite.
For amoebiasis, zinc appears useful as an add-on treatment.
Schistosoma
Schistosomiasis is caused by a parasitic worm. Research shows:
- In African schoolchildren with schistosomiasis, zinc supplementation had no effect on worm burden compared to placebo after 1 year.
- However, zinc supplements improved anemia and hepatomegaly caused by schistosomiasis.
Zinc may help manage some symptoms but does not eradicate the worms.
Other parasites
Smaller studies examine zinc for cryptosporidiosis, ascariasis, trichuriasis, and hookworm. Results are mixed:
- A trial in Bangladeshi children found zinc improved diarrhea from cryptosporidium but did not significantly decrease infection duration.
- Zinc reduced reinfection rates for Ascaris lumbricoides in Chinese children.
- However, zinc did not improve Trichuris trichiura infections.
- Zinc supplements slightly improved anemia in Vietnamese women with hookworm but did not reduce worm burden.
Overall the anti-parasitic benefits of zinc against other parasites remains uncertain. Larger, high-quality trials are needed.
How to use zinc for parasites
More evidence is needed before recommending zinc specifically for treating parasites. However, zinc supplements may provide some benefits based on the current research:
- Dosages in clinical trials range from 10-70 mg elemental zinc daily, often continuing for months.
- The RDA for zinc is 8 mg for adult women and 11 mg for adult men. Excess zinc can impair copper absorption and immune health.
- Oral zinc gluconate, acetate, or citrate supplements are best absorbed.
- Zinc taken with food reduces side effects like nausea.
- Look for supplements with USP certification and only use as recommended.
- Zinc appears most beneficial for children in developing countries who are deficient and have multiple infections.
Zinc should only be used as a supplement to standard anti-parasitic medications under the supervision of a doctor. Self-medicating with zinc for parasites is not recommended.
Are there any risks or side effects?
Oral zinc supplements are considered safe when taken at recommended dosages but there are some potential side effects to be aware of:
- Nausea, vomiting, diarrhea, metallic taste, kidney problems, and nerve pain are possible.
- Excess zinc can interfere with copper and iron absorption, alter HDL cholesterol, and harm immune cells.
- High zinc intake above the tolerable upper limit (40 mg/day for adults) is not advised long-term.
- Discontinuing zinc supplements abruptly after long-term use can impair immunity.
- Zinc can interact with antibiotics like quinolones and tetracyclines. Discuss with your doctor.
Rarely, excessive zinc intake over months can even result in copper deficiency with neurological problems if intake exceeds 150 mg/day. For this reason, close medical supervision is important if using zinc long-term.
Food sources of zinc
Rather than relying on supplements, getting adequate zinc from foods like:
- Oysters
- Beef and poultry
- Legumes like chickpeas
- Nuts like cashews
- Seeds like pumpkin and sesame
- Dairy products
- Whole grains
- Fortified cereals
…is the preferred strategy. A diverse, balanced diet provides zinc along with other important nutrients.
However, those following restricted diets like vegetarian/vegan may need supplements to meet their zinc needs along with medical monitoring.
The bottom line
In summary, the research on whether zinc supplements can eradicate parasites is variable:
- Zinc shows modest benefits against giardia, particularly in malnourished children.
- For amoebiasis and some other parasites, zinc may provide added benefit to standard antibiotics.
- However, zinc does not appear to eliminate roundworms and schistosomiasis.
- Higher quality clinical trials are still needed to clarify the role of zinc against common parasites.
Though more research is underway, zinc is not a standalone cure for parasitic infections as of now. Conventional parasite treatments should be used, with zinc only considered as an adjunct therapy under medical supervision.
But ensuring adequate zinc status through whole foods or a standard multivitamin may support immune function and overall health for parasite prevention. Those concerned should seek testing and personalized advice from their healthcare provider.