After iron, zinc is the second most abundant trace mineral in the body and is present in every cell. Unlike iron, however, the body doesn’t store zinc. This is why consuming adequate amounts of zinc through food is essential.
Due to its impact on the body’s anabolic hormone levels, zinc is a crucial mineral for athletes. Sports nutritionists also claim that absorbable zinc leads to an increase in plasma testosterone levels.
9 Potential Benefits of Zinc
- Increases Strength
- Increases Testosterone
- Reduces Infection Rates
- Reduces Inflammation
- Stimulates Muscle Growth
- Boosts the Immune System
- Increases Growth Hormone
- Improves Cognitive Function
- Improves VO2 Max and Oxygen Efficiency
Zinc is an essential mineral that is not produced by the body, meaning you must obtain zinc through diet or supplementation. The main food sources for zinc include red meat, poultry, oysters, beans, milk, tofu, and nuts.
List of Zinc Rich Foods
- Oysters (32 mg per 6 oysters)
- Beef (7 mg per 3 oz.)
- Crab (4.7 mg per 1 can)
- Lobster (3.4 mg per 3 oz.)
- Pork (2.9 mg per 3 oz.)
- Chicken (2.4 mg per 3 oz.)
- Cashews (1.6 mg per 1 oz.)
- Chickpeas (1.3 mg per 1/2 cup cooked)
- Swiss cheese (1.2 mg per 1 oz.)
- Kidney beans (0.9 mg per 1/2 cup cooked)
- Almonds (0.9 mg per 1 oz.)
- Mushrooms (0.4 mg per 1 cup raw)
- Kale (0.3 mg per 1 cup cooked)
Zinc is critical to several bodily functions. When people experience a zinc deficiency, there can be a lot of unpleasant and unwanted side effects, including impaired physical growth and development, increased risk of infection, reduced cognitive function, and impaired memory.
If you suspect you may be zinc deficient, you can test your zinc levels by hair analysis, blood work, or liquid zinc assay. Liquid zinc assay is the easiest way to test your zinc levels. To perform this test, you can take a teaspoon of zinc assay, and if you’re zinc deficient, the liquid will taste like water. If you have a slight deficiency, there will be a delayed metallic taste (10-15 seconds later).
If your zinc levels are adequate, there will be a metallic taste but not an intense flavor; however, if your zinc levels are optimal, you will notice an immediate, unpleasant metallic taste.
Zinc and Exercise Performance
Research shows that people who participate in high-intensity exercise for long periods have decreased levels of zinc in their bodies. If your zinc levels decrease too much, exercise performance can be affected by muscle contractions and the body’s inability to recover properly after workouts.
One study published in Sports Medicine found that endurance athletes lose more zinc than non-athletes through urine and sweat. For athletes, optimal zinc levels are, without a doubt, necessary.
Studies show that zinc supplementation may increase VO₂ max, which is a measurement of how much oxygen your body supplies to your muscles. If VO₂ is too low, it means your muscles are not getting enough oxygen, which will impair athletic performance. Zinc also plays a crucial role in several aspects of the immune system and the development and function of cells that control immunity.
Research published in the Journal of Physiological Sciences shows that zinc helps to decrease oxidative stress, and increase the synthesis of three important hormones responsible for building muscle: testosterone, growth hormone (GH), and insulin-like growth factor (IGF-1).
Zinc deficiency, which is often associated with old age, has been found to affect both innate and adaptive immunity. While frequent exercise can lead to zinc deficiency, this deficiency isn’t just capable of causing immune system dysfunction; it can also cause chronic inflammation regardless of age.
Furthermore, there’s a strong link between zinc deficiency and several infectious diseases such as pneumonia, bacterial infections, and a reduced defense against HIV and tuberculosis.
Zinc and Muscle Growth
Zinc elevates anabolic hormones, including growth hormone, Insulin-like growth factor, and testosterone. Research shows that athletes with low zinc levels also exhibit low serum testosterone levels. This is important because testosterone levels affect muscle growth, strength, body fat composition, and recovery.
A study reported in Biological Trace Element Research found that cyclists who supplemented with zinc for 4-weeks had increased growth hormone and insulin-like growth factor levels after exhaustive exercise.
At the end of the study, the cyclists also scored improved recovery times and increased their muscle size and strength. Aside from supplementation, you can obtain zinc through a variety of food sources.
Individuals who eat meat are less prone to zinc deficiency than vegetarians and vegans, but it’s still possible to get enough zinc in your diet without eating meat.
Zinc and the Immune System
Zinc is critical to the functioning of the immune system; and a zinc imbalance (be it a deficiency or an overload), can cause severe immune problems.
Furthermore, zinc plays a significant role in the development and aggravation of diseases. Zinc deficiency may also cause a delay in wound healing, while, at the same time, increasing inflammation and oxidative stress in the body.
A study reported in the journal Innate Immunity found that zinc deficiency increased susceptibility to infections and caused zinc-dependent alterations in the formation of innate muscle cells.
Zinc doesn’t just maintain the cells’ structural integrity, zinc also ensures the immune system fights off viral and bacterial infections. Unfortunately, since we lose most of our zinc through sweat, athletes are more likely to experience zinc deficiency. This zinc deficiency compromises muscle function, and it also increases susceptibility to viral infections such as the common cold.
Therefore, maintaining optimum zinc levels is vital for maximizing athletic performance. Having a strong immune system helps athletes fight off illness as they recover from strenuous exercise.
A study by the University of Michigan found that older adults who took 45 mg of zinc for a year reduced their frequency of viral infections and lower inflammatory markers by a considerable margin.
When choosing a zinc supplement, there are a few options worth considering:
Zinc Gluconate: one of the most common forms of zinc, zinc gluconate, is often used in cold remedies.
Zinc Acetate: is added to cold medications to reduce symptoms and speed up recovery.
Zinc Picolinate: is the most bioavailable form of zinc.
Zinc Orotate: is bound to orotic acid and is one of the most common zinc supplements.
Zinc Citrate: has similar absorption rates to zinc gluconate, but has a less bitter taste.
Safety and Side Effects
Too much zinc or too little zinc has the potential to be harmful and elicit unwanted side effects. For the most part, it’s difficult to overdose on zinc when you get zinc from food.
On the other hand, if you take zinc supplements, it’s important to be aware that zinc concentrations can reach toxic levels quickly. Zinc toxicity can produce both acute and chronic symptoms such as nausea, vomiting, lethargy, fatigue, diarrhea, abdominal cramps, and a weakened immune system.
Zinc supplementation can also lead to deficiencies in nutrients that compete for absorption in the body. For example, too much zinc can interfere with the absorption of copper and iron.
A study by the University of Arizona confirms that high levels of zinc at around 60 mg per day can cause decreased levels of copper, resulting in anemia, cardiac arrhythmias, and low levels of “good” cholesterol.
Zinc induced copper deficiency may also cause bone marrow suppression and genitourinary complications. Therefore, increasing your copper intake is advisable if you supplement with zinc for more than one week.
Before supplementing with zinc, it’s worth taking a blood serum or zinc assay test to determine if you have a zinc deficiency. The tolerable upper limit for zinc is 40 mg per day. And the recommended daily intake for zinc is 11 mg for men and 8 mg for women. This recommended daily intake is attainable through diet alone.
However, if you take a zinc supplement, you must ensure you take either zinc acetate, sulfate, citrate, or gluconate, as opposed to zinc oxide, as this form of zinc is hard for the body to absorb.
Effectiveness of Zinc
Zinc has a significant effect on the immune system and helps reduce inflammation. Zinc also plays a vital role in supporting growth hormone and testosterone production. All these factors combined mean that zinc is essential for athletic performance, muscle growth, and strength gains. People who exercise are at higher risk of losing zinc through sweat and fluid loss.
While zinc is critical for optimal body functioning, this doesn’t mean you should start supplementing with zinc. Before you supplement with zinc, you should test to see if you have a zinc deficiency first. In general, it’s much safer to get zinc through food, as research shows that taking zinc supplements in high doses can be dangerous and lead to serious side effects.