Although, the maximum safe dose of zinc is only 40 mg a day, most zinc supplements contain higher doses per tablet. You should avoid taking higher dosages for weeks, without consulting your healthcare provider.
Health benefits of zinc
Zinc is essential for good health. It is required for the activity of over 100 enzymes! Actually, zinc is the second most abundant trace mineral in the human body after iron. We have about 3,000 mg of zinc stored in our bodies.
The zinc deficiency is pretty common worldwide. It is estimated that about 2 billion people are deficient in zinc.[1]
People having low levels of zinc can benefit the most from taking zinc supplements.
Zinc plays a key role in the proper function of metabolism, protein synthesis, sense of taste and smell, boosting the immune system, controlling blood sugar levels, wound healing, and protecting the skin and eyes.
Moreover, zinc is crucial for autophagy. Autophagy is a process by which cells degrade and get rid of their damaged components. Autophagy seems to prolong lifespan, fight bacteria and viruses, protect against Parkinson’s disease and certain forms of dementia. Also, autophagy is promising for the treatment of certain cancers. Fasting stimulates autophagy. In 2016, Japanese scientist Yoshinori Ohsumi won the Nobel Prize for his discoveries into the mechanisms of autophagy.[2,3]
What’s the recommended daily intake?
Men have higher demands for zinc than women. The recommended daily intake of zinc is 11 mg for men and 8 mg for women.[4]
Men require high amounts of zinc, as it’s involved in the synthesis of testosterone and other hormones important for increased sex drive and fertility.
Do athletes require higher doses?
Zinc plays a key role in protein synthesis, maintaining protein structure and stability. Actually, one in every ten human proteins is a zinc protein. It plays a key role in muscle regeneration!
Zinc is necessary for athletic performance, particularly in endurance sports. First, high doses of zinc can reduce blood viscosity. Lower viscosity promotes oxygen delivery, which leads to improved aerobic performance.[5]
Additionally, zinc may help increase muscle strength and develop type I fiber, which plays a key role in endurance exercises, such as running or cycling.
Endurance athletes may need more zinc than the recommended daily dosage of 11 mg. Even a daily dose of 20 mg may not be enough. In a study, participants increased their VO2peak, only after a daily zinc dose of 30 mg for 6 weeks.
Zinc supplementation can’t instantly improve sports performance, though. It seems that athletes should take high dosages of zinc for weeks to totally replenish zinc stores in the body.
Zinc deficiency is common in athletes, impairing endurance performance. Zinc depletion leads to increased lactic acid and muscle fatigue.
Furthermore, high levels of zinc are beneficial for athletes for faster muscle recovery after strenuous exercise. Zinc has antioxidant properties that neutralize exercise-induced free radicals, helping muscle recover faster.[6]
In acute zinc deficiency, the human body can retrieve zinc from the bones. Thus, athletes with chronic zinc deficiency have a higher risk of developing osteoporosis!
What’s the maximum dose of zinc I can safely take a day?
The maximum safe dose of zinc for adult men and women is 40 mg a day. It’s less for teenagers, kids, toddlers, and babies. It depends on age. In fact, the maximum safe zinc dosage for:
- teenagers is 34 mg
- children of 9–13 years is 23 mg
- children of 4–8 years is 12 mg
- toddlers is 7 mg
- babies is 4-5 mg
Long-term higher dosages may cause side effects and deteriorate our health. Only people who take zinc supplements for medical treatment could receive higher doses than the maximum safe dosage!
Adults with zinc deficiency would probably benefit from taking zinc supplements. You’ll find a wide variety of zinc supplements on iHerb.
However, many dietary supplements contain 50 mg of zinc per tablet. This amount is higher than the maximum safe dose. Most healthy adults may need only half of this dose per day, though. In this case, you could only take half of the tablet.
Always consult your physician before taking dietary supplements or changing your diet.
Side effects of consuming too much zinc
Zinc supplements may interact with several types of medications, such as antibiotics or diuretics. Zinc may inhibit their absorption, reducing their effectiveness.
Furthermore, high daily dosages of zinc may cause side effects, such as nausea, vomiting, loss of appetite, abdominal cramps, diarrhea, headaches, low levels of copper, and reduced immune function!
For instance, high dosages of zinc of 60 mg a day for 10 weeks can inhibit the absorption of copper, leading to copper deficiency over time.
Moreover, according to a big study, analyzing data of over 3,500 people, high zinc doses of 80 mg a day significantly increased hospitalizations for urinary complications.[5]
Which food has more zinc than the maximum safe dose?
We can get too much zinc from food only by eating oysters. A serving can exceed the maximum safe dose! Fish and other seafood are also high in zinc. But, their consumption won’t cause zinc overdose.
Red meat and poultry are also great dietary sources of zinc. Actually, they’re the main sources of zinc in the standard American diet.
Other common foods high in zinc are beans, seeds, and nuts. In fact, we can get more than enough zinc from plant-based sources.