By Dr. Mercola
Zinc, an essential trace mineral, is perhaps most widely known for its role in immune system health, as a zinc deficiency is associated with increased colds and flu. However, zinc is the most common mineral in your body aside from iron; it's actually found in every cell.1
You might not be aware that zinc also has potent antioxidant properties, helping to neutralize free radicals that may accelerate aging and contribute to the development of chronic diseases like cancer and heart disease.
New research shows, however, that zinc may boost heart health in another way as well, antioxidant properties aside.
Zinc May Help Regulate Your Heartbeat
Researchers from the University of Leicester uncovered that zinc plays a key role in regulating the way calcium moves in your heart cells.2 Normally, calcium is released through "gates" known as type-2 ryanodine receptors (RyR2).
Proper control of these gates is important, since excessive calcium release may lead to heart failure and fatal arrhythmias (irregular heartbeat).3
The researchers studied individual heart cells and found zinc directly interacts with and modulates RyR2 function, thereby playing an important role in your body's release of intracellular calcium stores.
Samantha Pitt, a Royal Society of Edinburgh Biomedical Fellow at the University's School of Medicine, told Medical Xpress:4
"Our discovery provides a mechanistic explanation of how zinc plays a key role in regulating heart muscle contractility and how imbalances in zinc may contribute to diseases such as heart failure and fatal arrhythmias.
… The ability of zinc to modulate RyR2 channels in the absence of calcium represents a paradigm shift in our understanding of how RyR2 is activated when heart muscle contracts.
Although just a first step, this kind of basic science research underpins our understanding of the pathophysiology of disease."
Past research has shown patients with congestive heart failure often have profound zinc deficiency,5 which adds to the growing support that zinc is crucial for heart health, and underscores the importance of consuming enough of this mineral via your diet.
Richard Rainbow, a lecturer in Cardiovascular Cell Physiology at the University of Leicester, continued in Medical Xpress:6
"It always amazes me that seemingly small changes in the concentration of an ion have such profound effects on cardiac cell function that, when in the context of the whole heart, would have severe consequences."
Your Body Contains More Than 300 Zinc-Dependent Enzymes
Zinc is a constituent of at least 3,000 different proteins in your body and a component of more than 300 different enzymes. In fact, zinc is involved in more enzymatic reactions in your body than any other mineral. For this reason, even mild zinc deficiency may impact numerous aspects of your health, including:
The function of your immune system may markedly decrease in as few as four weeks after eating a low-zinc diet.7
Zinc affects multiple aspects of your immune system, including neutrophils, natural killer cells, phagocytosis, cytokine production, antibody production, and even gene regulation within your lymphocytes (white blood cells).
Research suggests high-dose zinc lozenges may shorten the duration of the common cold.8
Zinc works with vitamin A to help your eyes sense light and communicate via nerve impulses with your brain.
The Age-Related Eye Disease Study (AREDS1) found a supplement containing zinc (80 milligrams), vitamin C, vitamin E, beta-carotene and copper helped slow down the damage associated with age-related macular degeneration (AMD).9
Zinc deficiency may play an important role in the development of Alzheimer's disease. The disease is linked to accumulation of clumps of defective proteins in your brain, and zinc, it turns out, may be critical for preventing such accumulation.10,11
Zinc is required to produce an enzyme called carbonic anhydrase (CA) VI, critical to taste and smell, which is why loss of sense of smell or taste is one of the classic signs of chronic zinc deficiency.
It's been estimated that 15 percent of elderly people who lose their sense of smell may have a zinc deficiency.12
When men ate a zinc-deficient diet, the health of their sperm suffered in terms of both quantity and quality.13 As noted by the George Mateljan Foundation:14
"This study demonstrated that even brief periods of severe zinc deficiency can lead to measureable changes in sperm composition and quantity. Studies correlating diseases known to impair zinc nutrition with reduced fertility seem to second this conclusion."
Attention Deficit Hyperactivity Disorder (ADHD)
Research suggests children with ADHD have lower zinc levels than children without the condition.15
Among children with low levels of zinc and ADHD, there is some evidence that zinc supplementation may lead to improvements in symptoms such as hyperactivity, impulsivity, and impaired socialization.16
How Much Zinc Do You Need?
It's estimated that about 12 percent of the U.S. population may be at risk of zinc deficiency, and this rises to up to 40 percent among the elderly, who often have less intake and more difficulty absorbing this nutrient from food.17
Even under the best circumstances, your body may absorb only 20 percent to 40 percent of the zinc in your food.18 Further, the zinc in animal foods is better absorbed than that from plant foods, and zinc is best absorbed when consumed along with protein.
For adults, the RDA for zinc is about 11 milligrams (mg) per day for adult men and 8 mg for women. If you are lactating or pregnant, you need about 3 mg more. For children, 4 to 8 year olds need about 5 mg, and 9 to 13 year olds need 8 mg, while infants need only about 3 mg.
In addition to the elderly, people who have certain health conditions may be at increased risk of zinc deficiency:19
- Cirrhosis (liver disease)
- Kidney disease
- Celiac disease
- Inflammatory bowel disease (ulcerative colitis and Crohn's disease)
A number of other factors also contribute to the overall problem of zinc deficiency:
- Years of industrial farming practices, such as monocropping (planting large expanses of land with the same crop year after year) and tilling the soil, have left our soils deficient in natural minerals, like zinc
- Genetically engineered (GE) foods, as glyphosate, the active ingredient in herbicides like Roundup, is a mineral chelator, which means it binds specific nutrients, especially zinc
- Certain drugs deplete your body of zinc, such as ACE inhibitors, thiazide diuretics, and acid-reducing drugs like Prilosec and Pepcid
- Certain diets, such as vegetarian/vegan diets and high-grain diets, are low in bioavailable zinc and high in phytic acids, which impair zinc absorption
What Are the Best Food Sources of Zinc?
As mentioned, animal products are by far the richest in dietary zinc, as you can see in the table below. Oysters tip the scales at up to 182 mg per serving, but grass-fed beef is also a good source, with about 1 mg of zinc per ounce.20
Other good sources include poultry, raw cheese (especially Swiss and gouda), wild-caught seafood and shellfish, raw milk kefir and yogurt, beans, sesame seeds and pumpkin seeds. If you're relying on plant sources of zinc, soaking seeds and allowing them to sprout may significantly improve zinc bioavailability.21
If you are healthy and you eat a well-balanced diet, you will rarely need supplements to complete your body's zinc needs, and you should strive to get zinc from dietary sources. Taking too much zinc in supplement form can be dangerous, as it can interfere with your body's ability to absorb other minerals, especially copper. If you decide to use a zinc supplement, chelated forms are better absorbed than inorganic forms, or zinc salts.
Food Serving Size Zinc (mg) Oysters 100 grams (3.5 ounces) 16 to 182 Liver 100 grams 12 Pumpkin seeds (roasted) 100 grams 10 Roast beef 100 grams 10 Tahini (ground sesame seeds) 100 grams 10 Unsweetened chocolate 100 grams 9.6 Alaska King Crab 100 grams 7.6 Lamb 3 ounces 7.4 Cashews (dry roasted) 100 grams 5.6 Pork Shoulder 100 grams 5.0 Almonds 100 grams 3.5 Cheddar Cheese 100 grams 3.1 Chicken Leg 100 grams 2.9 Chicken Breast 100 grams 1.0