Zinc for Antiviral Protection
Like all minerals, zinc serves a wide range of necessary biological functions, but now, more than ever, we need to ensure we have an adequate supply of this nutrient critical to our immune system.
Along with supporting immune function, zinc also is required for brain development, wound healing, eyesight, testosterone production, fertility, prostate health, collagen synthesis, cellular energy production, and the senses of taste and smell (thus zinc deficiency is linked to anorexia).
When it comes to the immune system, zinc helps to regulate the production of T cells by the thymus gland. Zinc is also necessary for producing SOD (Superoxide Dismutase), one of our primary, internally-generated antioxidants, required to fight free radical damage.
As well as being generally required by the immune system, zinc has a specific benefit when facing viral threats. Published clinical studies support the fact that supplementing with zinc is beneficial for treating both acute lower respiratory tract infections, and tuberculosis. (Study) And, remember it is the respiratory tract infections that actually kill people when they cannot recover from certain viruses (as it was with the Spanish Flu).
Zinc and the Thymus Gland
As we age, starting somewhere around the age of 40, our thymus gland begins to shrink, accompanied by a decline in blood serum levels of zinc, which drops about 3% every decade following.
During this process the thymus gland reduces its output of thymulin, the hormone that stimulates the production of T cells, the killer cells which protect us from infection (and prevent tumor growth). By the time the average person reaches the age of 65, the thymus gland has usually shrunk so much that it only releases about 10% of the thymulin that it did when we were young. This decline impedes our immune system’s ability to fight off both disease and infection.
However, when researchers gave zinc to experimental animals, they found the thymus gland regained around 80% of its normal size, and the T cell and thymulin production returned to healthful levels. Human studies followed those animal studies finding that when people aged 65, and older, were given only 15 mg of zinc daily, they also started producing T cells, and thymulin, at youthful levels. (Source)
Zinc and the Elderly
Since studies have already established that zinc supplementation decreases incidence of infections in the elderly, a newer study sought to determine the effect of zinc on generation of cytokines (inflammatory compounds) and oxidative stress, in seniors.
The study concluded: “After zinc supplementation, the incidence of infections was significantly lower, plasma zinc was significantly higher, and generation of tumor necrosis factor alpha and oxidative stress markers was significantly lower in the zinc-supplemented than in the placebo group.” (Study)
The Problem with Zinc Lozenges
While in vitro studies have long shown that zinc inhibits the common cold rhino-viruses, the experimental data has been mixed when the zinc studies have used throat lozenges. Scientists have now identified a flaw in the studies that used hard-candy zinc lozenges containing citric acid. It seems the low pH produced by the acidic formulation inhibited zinc delivery. (Study)
Building on this knowledge, a new study, conducted at Dartmouth College, found that college students given non-acidic throat lozenges one day into their cold had colds that were more than 50% shorter. For those students taking look-alike, taste-alike placebo candies, colds lasted 9.2 days on average, versus 4.3 days for those taking zinc. (Study)
Zinc Depletion Zinc serum levels can be reduced by diarrhea, kidney disease, cirrhosis of the liver, diabetes, and overconsumption of fiber. The adult recommended daily intake for zInc is 15 mg per day. While one can certainly take more than 15 mg for a while, as with all nutrients, I suggest taking zinc only 5 days a week. Taking a break allows the body to use up any excess zinc that we might ingest through supplementing: consider it a safety-valve.
One of the better absorbed forms of zinc is zinc citrate, which we use in our NutriPods (multivitamin packs), and our stand alone mineral formula, Mineral Mix. Mineral Mix contains 15 mg of zinc citrate per serving (2 caps), and NutriPods Original, and NutriPods for Women, also each contain 15 mg of zinc citrate per serving. NutriPods for Men contains 20 mg of zinc citrate, as men have higher zinc requirements than women do.
Excessively high amounts of zinc (above 150 mg) can seriously depress the immune system and increase susceptibility to disease. Continued intake of 25 mg, or more, per day can also interfere with the body’s absorption of copper. Fortunately, when taking zinc in a multivitamin, or mineral complex, copper is also provided, so this is not of concern.