Known for its contributions to a healthy immune system, zinc has a starring or supporting role in dozens of clinical trials studying ways to prevent COVID-19 infection and improve outcomes. But zinc is far more than an immune booster. This mineral, which comprises a measly 0.0036% of the body mass of a 150-pound human, is critical for many aspects of your health.
So how does zinc work in your body? How can you make sure you get what you need? Can you get it from food alone, or do you need to supplement? Is there such a thing as too much zinc? And can sucking on a zinc lozenge prevent or shorten the duration of a common cold? This article explores the ins and outs of zinc so you can get the right amount of this important mineral.
The Protective Power of Zinc
Before we get into the ins and outs of zinc, a story:
One day, early in the 19th century, the Royal Navy came to the chemist and inventor Sir Humphrey Davy with a big problem. To protect their ships from a kind of mollusk that bored into wood, ship makers had been lining the bottoms of these vessels with copper. Unfortunately, the saltwater quickly corroded the copper, which led to costly and highly inconvenient repairs. Could Davy come up with a solution?
Davy suggested attaching a “sacrificial metal” to the copper. His element of choice was zinc. The zinc would protect the copper by being degraded by the saltwater, a process termed “galvanization” that later protected iron, steel, and other industrial metals from corrosion.
The story ends sadly for Davy and the Navy (which kind of sounds like a TV sitcom band from the 1970s!). While the zinc stopped the deterioration of the copper, it also made it far more susceptible to weeds and barnacles by providing them with nutrients that they found appealing. But it highlights the power of zinc, which can protect not only copper and iron but us as well.
What Is Zinc?
Zinc is a naturally occurring trace mineral that your body needs to fight off bacteria and viruses. The adult body contains about two to three grams of zinc — approximately the weight of a penny — which is stored mainly in fluid, bones, tissues, and organs.
Zinc is essential for growth in humans, animals, and even plants. (If your pecan tree isn’t producing nuts on a regular basis, make sure you fertilize with zinc in late winter.) Zinc is used in the process of cell division to create your unique DNA and plays a significant role in promoting wound healing. And it’s crucial for fertility to maintain levels of the reproductive hormones testosterone and estrogen. Zinc also comes into play with the metabolism of fats and sugars, helping to regulate and express insulin. And, zinc is largely linked to your sense of smell and taste, although the exact way this occurs is unknown.
7 Health Benefits of Zinc
As you can see, zinc is an essential nutrient for a healthy, functioning body. Here are seven important reasons to ensure you get enough zinc.
1. It keeps your immune system healthy.
It appears that every immunological event relates in some way to zinc. There’s a strong connection between zinc deficiency and susceptibility to disease. A Cochrane Library meta-analysis of six studies that included a total of over 5,000 children between two months old and five years of age found that zinc supplementation reduced the incidence of pneumonia. And according to findings from a 2011 Cochrane review, zinc effectively shortens the duration and severity of the common cold (by approximately one day, so don’t get too excited).
People who are infected by Covid 19 and are zinc-deficient develop more complications, are more likely to require hospitalization, have longer hospital stays, and are more likely to die. While there’s not yet enough evidence to officially recommend zinc for the prevention or treatment of COVID-19, especially in amounts that exceed the RDA, research is ongoing for its potential use, and some initial studies have been promising.
2. It may improve pregnancy outcomes for mothers and infants.
The World Health Organization estimated in 2013 that a majority of pregnant women worldwide were at least somewhat deficient in zinc. This may contribute to the likelihood of poor birth outcomes and stunted infant development. The WHO recommends micronutrient supplementation (including zinc) for pregnant women who may be at risk of zinc deficiency.
3. It may help protect against neurodegenerative disorders.
No, zinc is not the fictional brain-enhancing drug NZT-48 from the movie Limitless. Taking it won’t make you smarter, or (spoiler alert) make you rich and powerful (or even look like Bradley Cooper).
Now the good news. Many people can prevent age-related neurodegenerative disorders, like Alzheimer’s, with diet and lifestyle habits. Getting enough zinc is a key part of this prevention strategy; it acts as an antioxidant, preventing oxidative stress in the brain that could otherwise increase your risk for neurodegeneration. In fact, an imbalance of iron and zinc ions (too much iron and not enough zinc) has been shown to lead to Alzheimer’s and Parkinson’s disease symptoms.
4. It helps regulate hormones.
Zinc plays a huge role in regulating your hormones, including growth hormone, insulin, leptin, thyroid hormone, melatonin, and sex hormones. Getting enough zinc is important for the functioning of your endocrine system. When it isn’t, your various organs and systems can’t communicate well, which can wreak havoc on your health, your energy, and your mood.
5. It helps improve blood sugar regulation.
According to a 2015 review of both test tube and human studies, zinc has many beneficial effects on both type 1 and type 2 diabetes. Specifically, zinc appears to play an important role in pancreatic β-cell (that funny-looking thing that looks like a capital B is a symbol for beta) function, the activity of insulin, modulation of glucose, and the process by which diabetes develops and has complications.
So if you’re trying to prevent, reverse, or manage diabetes, in addition to watching your weight and eating a largely plant-based diet, make sure you get enough zinc to keep your pancreas firing on all cylinders (or whatever metaphor you want to apply to your pancreas).
6. It may offer protective effects against cardiovascular disease.
In a 2015 meta-analysis, researchers found that zinc supplementation significantly reduced total cholesterol, LDL “bad” cholesterol, and triglycerides, which are risk factors for heart disease when elevated. And studies show that having adequate levels of zinc in your body may help prevent plaque buildup in your arteries, which can protect your heart.
7. It may improve vision and protect against eye disease.
Zinc works alongside vitamin A and other antioxidants to support eye health and normal vision. It helps vitamin A produce melanin, a protective pigment found in your eyes (as well as in your skin and hair). Not getting enough zinc can also worsen your night vision. Some research indicates that zinc supplemented with antioxidant vitamins can slow the progression of age-related macular degeneration — a condition in which the central field of vision becomes blurred or lost over time. This is a pretty significant contribution considering macular degeneration is the leading cause of blindness among the elderly in Western countries.
How Much Zinc Do You Need?
The Recommended Dietary Allowance (RDA) for zinc is fairly small in comparison to other vitamins and minerals. Although it increases from infancy to teenage years, it largely remains the same throughout adulthood.
Below are the RDAs for zinc based on age group:
- 0-6 months: 2 milligrams (mg)
- 7-12 months: 3 mg
- 1-3 years: 3 mg
- 4-8 years: 5 mg
- 9-13 years: 8 mg
- 14-18 years: 9 mg (girls), 11 mg (boys)
- 18+ years: 8 mg (women), 11 mg (men)
- Pregnancy: 11-12 mg
- Breastfeeding: 12-13 mg
As you can see above, pregnant and breastfeeding women have unique zinc needs and are most at risk of deficiency. But it isn’t just child-rearing women who are at risk — in fact, estimates show about 17% of the entire world population is deficient in this mineral, with a higher incidence in South Asia and sub-Saharan Africa.
Early in life, zinc deficiency may present as stunted growth in children. Other symptoms may include lack of appetite, unintentional weight loss, loose stools, low energy levels, increased susceptibility to infections, loss of hair, skin rashes, impotence, and problems with vision, taste, or smell.
But how is zinc deficiency diagnosed? Because its symptoms are fairly generalized across a number of conditions, formal diagnosis usually involves ruling out other disorders that can present similarly. Your doctor may first do a complete blood count (CBC) panel to check for an infection or anemia first. If zinc deficiency is suspected, you physician may order a blood test.
Normal zinc blood levels are between 0.66 to 1.10 mcg/mL for anyone over 11 years of age.
Are You at Risk for Zinc Deficiency?
The risk for zinc deficiency depends on the individual and involves factors like age, diet pattern, medical conditions, and certain lifestyle habits.
The absorption rate for zinc from foods can range from 16-50%, meaning that the remaining zinc passes through the body unused. But what does that mean for you?
Some research indicates that those who follow a plant-based diet may need to eat as much as 50% more zinc than the recommended amounts to accommodate for the loss of absorption on account of phytates, or take a daily zinc supplement. As a result, plant-based eaters may experience greater rates of subclinical zinc deficiency than omnivores. The good news is that an individual’s current zinc status may influence their absorption rate — meaning that your body can adapt to a lower zinc status.
If you fall into some of these other categories, you may also be at a higher risk for developing zinc deficiency:
- Pregnant and breastfeeding women, who appear to have a higher prevalence of zinc deficiency, which can have long-term consequences for mom and baby
- Elderly individuals, who tend to eat fewer zinc-rich foods and lead less active lifestyles
- People who use alcohol chronically because alcoholism is linked to lower intracellular zinc levels and worsened immunity
- Smokers, because tobacco smoke is high in cadmium which appears to further reduce tissue concentrations of zinc in the body
- People with absorption disorders, such as ulcerative colitis, Crohn’s disease, celiac disease, or conditions with persistent diarrhea
- People who use high-dose iron supplements because taking iron with zinc supplements or zinc-rich foods may impair the absorption of zinc.
Plant-based eaters, and individuals at a heightened risk for zinc deficiency, may want to consider adding a zinc supplement.
Zinc supplements are available in capsules, tablets, and lozenges. There are also a number of types of zinc. One of the most cost-effective and widely available zinc types is zinc gluconate, which is the form most commonly found in cold and flu lozenges. However, according to some studies, zinc picolinate or zinc citrate appear to have better absorption rates. If you have trouble with acne, zinc sulfate may come with the added benefit of improving the appearance of your skin.
When it comes down to which is best, it doesn’t seem like you can really go wrong with most of the forms used in common supplements. However, some studies have linked zinc in nasal spray to a loss of smell, so you might want to steer clear of those.
A whole foods, plant-based diet can meet almost all of your nutrient needs in abundance. Almost. But there are a few nutrients of concern. Zinc is one such nutrient, and so, too, are B12, D3, DHA, EPA, K2, iodine, selenium, and magnesium.
Meeting your needs for these nutrients through supplements can become complicated and confusing. But that’s why we’re excited about a natural product called Complement Essential.
Complement Essential is made for plant-based eaters. It contains organic, non-GMO, and vegan ingredients. And it’s free of gluten, artificial fillers, additives, and preservatives. It also has the right amount of important nutrients your plant-based diet may be lacking — and nothing more. It doesn’t come with additional synthetic vitamins that you likely don’t need, which you might find in a typical multivitamin.
If you’re interested in Complement Essential, find out more about this product here. (Note: If you make a purchase, you’ll be supporting your health as well as the mission of Food Revolution Network.)
Zinc Toxicity and Risks
With all the benefits of zinc we’ve looked at, you might think that more is always better. It’s not. You can experience zinc toxicity if you take overly high doses of zinc supplements. Signs that you’re getting too much zinc may include nausea, vomiting, loss of appetite, diarrhea, stomach cramps, and headaches. If you get too much zinc over a longer period of time, you can experience additional problems like decreased copper levels, reduced immunity (for instance, getting sick more often), and sometimes reduced levels of HDL (“good”) cholesterol.
Understanding the upper limits of zinc supplementation can help you make sure you’re not consuming an unwise amount. In general, you’d probably have to take over 100 mg of zinc per day to start experiencing any negative effects — almost 10 times the recommended daily dose. Symptoms generally become evident at 100-200 times the recommended daily dose, with levels as high as 1-2 grams per day.
It’s also noteworthy that supplemental zinc may interact with certain drugs and medications. For instance, some antibiotics, penicillamine (a drug for the management of rheumatoid arthritis), diuretics, and even other minerals may interact or cause zinc absorption issues. It’s probably wise to speak with your healthcare provider before taking a zinc supplement, especially if you’re taking other medications or mineral supplements.
While some animal products — particularly oysters — contain high amounts of zinc, a diet rich in whole plant foods can provide you with a variety of plant-based sources of zinc.
For instance, whole grains, soy foods like tofu and tempeh, legumes, nuts, and seeds are all naturally rich in zinc. Just a one-ounce (30g) serving of pumpkin seeds contains two mg of zinc, and the same amount of hulled hemp seeds provides 3mg.
Increasing Zinc Absorption Rates
However, many zinc-rich plant-based foods are also high in phytates, which can reduce zinc absorption. One way to combat this is to prepare zinc- and phytate-rich foods in a way that reduces phytate content. You can reduce the phytate content of grains and legumes by soaking, sprouting, fermenting, or simply cooking them before eating. (You heard it here first: don’t eat wheat berries or black beans raw. You’re welcome!)
To increase zinc absorption, you can also eat zinc-containing foods with a source of protein. Amino acids like histidine (found in plant-based foods such as nuts, seeds, and whole grains) bond well with zinc in the body. However, eating a wide variety of whole plant foods, in addition to being a commonsense approach to diet in general, can help ensure you get enough zinc and other trace minerals. For example, those nuts and seeds are high in protein, and give you zinc as part of a total package of goodness.
While you may see zinc and vitamin C together in supplements aimed at reducing the duration and severity of the common cold, this is mainly because both micronutrients can have immune-enhancing properties. Vitamin C does boost the absorption of iron but doesn’t have the same effect on zinc. But citrate, a compound found in vitamin C-containing foods like citrus fruits, may help enhance zinc absorption. So, it doesn’t hurt to still eat vitamin C-rich foods like oranges, grapefruits, and lemons alongside zinc-rich foods.
Recipes with Zinc-Rich Foods
As you’ll see below, getting enough zinc (even if you’re striving for 50% more than the RDA) through whole plant-based foods doesn’t have to be hard! Try out oat flour in baking (like in the Berry “Scuffins” below), incorporate more organic soy products (check out the Lemon Herb Tofu), and combine several sources of zinc as seen in the Southwest Quinoa Salad. Plus, you get so many more nutrients in these dishes, including vitamin C, fiber, and iron!
1. Berry “Scuffins”
Zinc intake doesn’t get much tastier than this! Just one-half cup of oats provides 1.5 mg of zinc. (Have no fear — you cook the “scuffins,” so you can reduce those zinc-binding phytates.) The term “scuffins” is what you get when you combine a scone and a muffin, which means you can enjoy it for breakfast, as a snack, or as an after-dinner treat!
2. Lemon Herb Tofu
Wondering about your zinc intake? One way to consume a decent amount of zinc in just one meal is to enjoy tofu (1.8 mg of zinc in every four ounces) on top of whole grains (1-2 mg of zinc per cooked cup) along with your favorite veggies. Sprinkle some nuts and seeds on top for some crunch, flavor, and an extra dose of zinc!
3. Southwest Quinoa Salad
Both black beans and quinoa are rich sources of zinc. Since you need to cook beans and grains, you can reduce or eliminate much of the phytate content, making that zinc available to you! They’re also both packed with iron. What’s more, the vitamin C in the salsa and peppers helps enhance iron absorption. And the citrate in the lime juice allows your body to absorb more zinc from your meal. What we’re saying is that getting lots of nutrition on a plant-based diet can be simple — and as this salad will prove to you, delicious!
Get Enough Zinc, But Not Too Much
Zinc is an essential mineral for immunity. It also has protective effects on your heart, brain, eyes, hormones, and more. Although you can get zinc from food, many people, including plant-based eaters, may want to consider soaking, sprouting, and/or fermenting grains and legumes to reduce phytate content and increase zinc absorption. And some may also want to consider a bit of supplementation to protect against the risk of zinc deficiency.
Tell us in the comments:
- Do you use a zinc supplement?
- What zinc-rich foods do you enjoy? Which can you add to your diet?
- Have you ever used a zinc product to help reduce the duration and severity of the common cold?
Feature image: iStock.com/ratmaner