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If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.
When it comes to the ABCs of nutrition, we seem to pay a lot of attention to the first few letters and, well, not so much to those that come later. Vitamin A, calcium, vitamin D? We know they’re important and have a good idea of what they do. Magnesium and manganese?
Things get a little hazy, but Health Guide can help you with this. By the time we get all the way down to poor zinc, our knowledge of the subject may be as slim as “is that maybe an ingredient in sunscreen?”
But zinc is actually an essential nutrient. And since we can’t make or store it, our bodies rely on us to get enough each and every day through our diets or supplement plans.
And since zinc is the second most abundant trace mineral in the human body, only coming in after iron, it’s serious if you’re consistently not getting enough. Although only trace amounts are needed (the recommended dietary allowance is 11 mg per day for adult men and 8 mg per day for adult women), its role in your body is anything but.
Proper zinc intake helps keep your body functioning properly. This trace element plays an important role in wound healing and immune function, cell division, and the formation of DNA and proteins. It’s also vital for growth and development and influences taste and smell, and can potentially slow age-related macular degeneration.
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Zinc and testosterone
In case all of those jobs weren’t enough to convince you of this mineral’s importance, it also affects your testosterone levels.
You might have heard that oysters are an aphrodisiac. Well, they’re also one of the best food sources of zinc. Even moderate zinc deficiency is associated with hypogonadism (also called testosterone deficiency) in men, a dysfunction of the testes that results in a failure to produce testosterone, sperm, or both.
We probably don’t need to tell you, but low T may result in side effects such as altering body composition by increasing body fat, decreased strength and muscle mass, lowered sex drive, and even erectile dysfunction. These side effects may also show up if free testosterone is low, even if total testosterone comes back normal.
To see just how much this mineral could affect testosterone concentrations, researchers restricted dietary zinc intake in young men for 20 weeks. Over that time, their testosterone levels fell from an average of 39.9 nmol/L (nanomoles per liter) to 10.6 nmol/L (Prasad, 1996).
But the researchers in this study also wanted to look at the opposite. So they took elderly men who were minorly zinc deficient and put them on supplements for six months. Sure enough, after 24 weeks, their serum testosterone levels had improved. The average T level went from 8.3 nmol/L to 16.0 nmol/L, in the middle of the range for healthy adults.
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Though the study was small and more research would need to confirm just how much hormone levels are affected by zinc status, it underscores that there’s a clear connection between the two, much like the connection between vitamin D and testosterone.
Low zinc levels also interfere with spermatogenesis, the production of sperm, and may also cause sperm abnormalities as well as throw off serum testosterone. That’s bad news for over 9% of men in the United States aged 15–44 who have experienced fertility problems (Chandra, 2019; Fallah, 2018).
Zinc and other hormones
But it gets a little more complicated from there. Essentially, zinc is involved with multiple processes in your body that, if they break down, will shut down sex hormone production.
One of those is proper thyroid function. Zinc is essential for the production of thyroid-releasing hormones in your brain. When men don’t get enough zinc, their bodies not only don’t secrete thyroid hormones as they should but testosterone production is also affected.
Unfortunately, that also means things that negatively impact thyroid hormones can also lead to low testosterone levels. A common example is intense exercise. Exercise to exhaustion leads to a decrease in both thyroid hormones and testosterone concentrations in a group of wrestlers, one small study found.
But four weeks of treatment with zinc sulfate supplementation successfully prevented this effect. Another study looked at the same effect, but in sedentary males instead of athletes, but they found the same thing. Oral zinc treatment prevented a drop in both thyroid hormone and testosterone caused by exhaustion bicycle exercise (Kilic, 2007).
Additional benefits of zinc
There’s another important way this mineral can increase testosterone levels, and it’s also another one of the beneficial effects of zinc: it fights inflammation.
Inflammation is tied to oxidative stress, a state in which there’s an imbalance between free radicals that can cause cellular damage and antioxidants. Zinc can diminish oxidative stress by acting as an antioxidant in the body to rebalance the two sides, and that’s a vital function of this mineral (Marreiro, 2017).
And while oxidative stress is linked to many chronic diseases, it can also cause a drop in T levels because it can damage Leydig cells, which produce testosterone in the presence of the luteinizing hormone (LH) (Fallah, 2018).
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Proper zinc levels also support the immune system by helping with T-lymphocyte development, which boosts infection-fighting T-cells. Getting enough zinc is also critical to wound healing, so much so that the trace element is used with vitamin C to speed the healing of ulcers in a hospital setting (Bhattacharya, 2015).
And those same inflammation-easing effects are the root of why zinc (along with vitamin C, vitamin E, and beta carotene) may halt or slow the progression of age-related macular degeneration.
How to get enough zinc
For most people, food sources should be enough to hit the RDA. But since oysters and beef are some of the most potent sources of dietary intake, vegans and vegetarians may struggle to get enough without supplementing.
Other quality sources include nuts and seeds, dairy, and dark chocolate. Legumes and whole grains also contain zinc but may need to be soaked to reduce levels of phytate, a compound that blocks zinc absorption. Some foods, like certain breakfast cereals, are also fortified with the essential mineral.
But there are certain people who need zinc supplementation. Anyone with a gastrointestinal issue such as Crohn’s or celiacs, as well as those with liver disease, may struggle to absorb zinc from their diets and may need a high-dose supplement.
These people should work closely with a healthcare professional to monitor their zinc concentrations. For most people, a multivitamin or ZMA (a combination of zinc, magnesium, and vitamin B6) will meet their needs.
Just make sure to follow medical advice if you choose to use supplements. Too much zinc can also be dangerous and may cause magnesium deficiency.
- Bhattacharya, S., & Mishra, R. K. (2015). Pressure ulcers: Current understanding and newer modalities of treatment. Indian Journal of Plastic Surgery, 48(01), 004–016. doi: 10.4103/0970-0358.155260, https://www.ncbi.nlm.nih.gov/pubmed/25991879
- Chandra, A., Copen, C. E., & Stephen, E. H. (2019, December 5). CDC – NCHS – National Center for Health Statistics. Retrieved from https://www.cdc.gov/nchs/data/nhsr/nhsr067.pdf
- Fallah, A., Mohammad-Hasani, A., & Hosseinzadeh Colagar, A. (2018). Zinc is an Essential Element for Male Fertility: A Review of Zn Roles in Men’s Health, Germination, Sperm Quality, and Fertilization. Journal of Reproduction & Infertility, 19(2), 69–81. Retrieved from http://www.jri.ir/
- Honscheid, A., Rink, L., & Haase, H. (2009). T-Lymphocytes: A Target for Stimulatory and Inhibitory Effects of Zinc Ions. Endocrine, Metabolic & Immune Disorders – Drug Targets, 9(2), 132–144. doi: 10.2174/187153009788452390, http://www.eurekaselect.com/84432/article/t-lymphocytes-target-stimulatory-and-inhibitory-effects-zinc-ions
- Kilic, M., Baltaci, A. K., Gunay, M., Gökbel, H., Okudan, N., & Cicioglu, I. (2006). The effect of exhaustion exercise on thyroid hormones and testosterone levels of elite athletes receiving oral zinc. Neuro Endocrinology Letters, 27(1-2), 247–252. Retrieved from http://www.nel.edu/
- Kilic, M. (2007). Effect of fatiguing bicycle exercise on thyroid hormone and testosterone levels in sedentary males supplemented with oral zinc. Neuro Endocrinology Letters, 28(5), 681–685. Retrieved from http://www.nel.edu/
- Marreiro, D., Cruz, K., Morais, J., Beserra, J., Severo, J., & Oliveira, A. D. (2017). Zinc and Oxidative Stress: Current Mechanisms. Antioxidants, 6(2), 24. doi: 10.3390/antiox6020024, https://www.ncbi.nlm.nih.gov/pubmed/28353636
- Prasad, A. (1996). Zinc Status and Serum Testosterone Levels of Healthy Adults. Nutrition, 12(5), vi. doi: 10.1016/s0899-9007(96)00064-0, https://www.ncbi.nlm.nih.gov/pubmed/8875519
- Prasad, A. S. (2014). Zinc: An antioxidant and anti-inflammatory agent: Role of zinc in degenerative disorders of aging. Journal of Trace Elements in Medicine and Biology, 28(4), 364–371. doi: 10.1016/j.jtemb.2014.07.019, https://www.ncbi.nlm.nih.gov/pubmed/25200490