Zinc

A nutrient for centre stage

Zinc

The hard-working mineral zinc boosts immunity, fights cancer, and builds bones. Discover how zinc can do your body good.

Nutrients such as vitamins C and D and phytochemicals such as curcumin have been hailed as anticancer, antiaging superstars, garnering attention from the media and health- conscious consumers. Now another nutrient is poised to take centre stage—the often overlooked and under- appreciated mineral zinc.

Hard-working mineral

Zinc has some long-established roles in maintaining the body’s health. It is a proven immunity booster that supports the body’s response to pathogens. A plethora of studies suggest that the mighty mineral can help to reduce the severity and duration of the common cold. Besides being the bodyguard of your immune system, zinc also moonlights at other jobs ranging from maintaining healthy DNA strands to potentially aiding blood glucose control and helping maintain acid-base balance.

Good for your noggin

And speaking of balance, zinc can help you maintain yours. Recent research shows that insufficient zinc intake may lead to hypersensitivity to stress and an increased risk of depression and anxiety. Conversely, optimal intake promotes growth and mental alertness and aids in proper brain function.

In one surprising new animal study, scientists found that zinc supplementation greatly delayed hippocampal-dependent memory deficits in mice with a mouse model of Alzheimer’s disease. In another animal study researchers established that zinc deficiency increases the size of amyloid plaques—growths in the brain associated with Alzheimer’s disease. And not surprisingly, scientists have also found a correlation between low zinc levels and attention deficit hyperactivity disorder (ADHD).

Cancer fighter

Zinc’s “do-good” status doesn’t end there. The mineral also acts as an antioxidant and anti-inflammatory agent.

Antioxidants enhance health by fighting free radicals in the body that attack our cells and cause oxidative stress. Zinc quells inflammation by inhibiting a substance called NF-kappa B that activates inflammatory processes within our cells. Both oxidative stress and inflammation are ?contributing factors for many chronic diseases, including cancer. Some compelling evidence supports zinc’s role as an anticancer agent—a recent study found that nearly 65 percent of patients with head and neck cancers were zinc deficient.

Interestingly, another recent study suggested that zinc may also prevent and reverse damage to DNA. In one revealing study, when healthy men went from an adequate zinc intake to a dietary zinc depletion they showed more breaks on certain DNA strands. Re-establishing optimal zinc intake repaired the damage done to the men’s DNA.

How important is this finding? It is well known that cancer is caused by damage to DNA. Damaged DNA can also speed up the aging process and increase the risk for conditions such as Alzheimer’s disease.

Bone friendly

When most people think of “bone-friendly” minerals they immediately think of calcium. However, they should add zinc to the equation.

Scientists have shown that the intake of dietary zinc can cause an increase in bone mass. How? Zinc seems to have a stimulatory effect on osteoblastic bone formation and mineralization—in plain English, it builds bone. Furthermore, it inhibits osteoclastic bone resorption, which means that it also prevents bone loss.

Recent research confirms zinc as a major factor in bone health—supplementation with a compound called zinc acexamate was shown to have a restorative effect on the bone loss that can occur with various conditions, including aging. These new findings suggest zinc may play a significant role in the future prevention and treatment of osteoporosis.

Getting enough

In general, meeting the following recommended daily allowance (RDA) for zinc, established by the US Food and Nutrition Board, will ensure your intake is adequate.

Teens (ages 14 to 18)
Males: 11 mg
Females: 9 mg

Adults (ages 19 and older)
Males: 11 mg
Females: 8 mg
Pregnant women: 11 mg
Breastfeeding women: 12 mg

There are certain individuals, however, for whom “getting enough” may pose problems. The elderly often have a daily zinc intake below the RDA. Individuals taking medications regularly should also be vigilant about zinc intake because some drugs can interfere with zinc absorption. In addition, athletes, who can lose zinc through excessive sweating, may have increased demands for the mineral.

Because zinc from animal sources is more bioavailable than zinc from plants, vegetarians need to be savvy when preparing their food. Grains, legumes, and seeds all contain phytic acid that binds to zinc and hinders its absorption. Soaking these items for several hours before cooking will help to break down the phytic acids. Sprouting them will further break down phytic acid, thereby also increasing zinc’s bioavailability.

Supplements?

Is relying on supplements the answer to optimal zinc intake? While supplements shouldn’t be used as replacements for healthy eating, they can play a vital role in ensuring you’re meeting your body’s needs.

The safest way to achieve optimal levels of this key mineral is to take a broad-spectrum multivitamin/multimineral that contains 100 percent of the RDA for zinc. Remember— too much of one nutrient can interfere with your body’s ability to use other nutrients, and zinc is no exception. Zinc can impair your body’s ability to absorb copper, so do not go overboard.

In all instances, see your health care practitioner for advice.


Signs of zinc deficiency

Zinc deficiency symptoms include diarrhea, weight loss, unhealed wounds, increased susceptibility to infections, loss of sense of taste or smell, hair loss, growth retardation, skin rashes, white discolouration on fingernails, loss of appetite, menstrual cycle disturbances, behavioural disturbances such as depression, and acne.

Food sources of zinc

Food Serving size Amount of zinc, in mg
oysters 6, medium sized 76.3
crab 3 oz (85 g) 4.7
turkey, dark meat, skinless 3 oz (85 g) 3.8
miso 1 cup (250 mL) 1.8
soybeans, cooked 1 cup (250 mL) 1.6
cashews, dry roasted 1 oz (28 g) 1.6
wheat germ 1 Tbsp (15 mL) 1.2
baked beans 1/2 cup (125 mL) 1.8
egg 1, medium sized 0.5
yogourt (fruit) 1 cup (250 mL) 1.8
Swiss cheese 1 oz (28 g) 1.2
milk, whole 1 cup (250 mL) 1.0

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