A popular home-remedy for common colds is once again picking up steam.
It's zinc!
And with the cold season upon us, this supplement is flying off shelves as people try to strengthen their immune systems.
But is this remedy all hype, or does it actually work?
So before we get started, I’m going to throw out a disclaimer.
The jury is still out on how effective zinc is at treating any illness, including colds and even COVID.
What we do know is that zinc is an essential trace mineral.
Your body only needs tiny amounts, but it can still have big impacts on your health.
Zinc is involved in hundreds of essential biological reactions in the body.
It also aids in very important cellular processes like DNA replication, RNA transcription, and cell division.
The human body doesn’t make zinc, so we need to get it from our diets,
particularly from foods like oysters, red meat, poultry, and beans,
or from supplements.
According to the U.S. Food and Nutrition Board, the daily recommended dietary allowance of zinc
is 11 mg for men and 8 mg for women.
When we don’t have these minute amounts of zinc, our bodies don’t work properly,
so people who are zinc deficient are often treated with supplements.
But the benefits for people with normal zinc levels has remained unclear.
The efficacy of zinc supplements for treating the common cold has been debated as far back as the 70s,
when researchers observed that zinc also inhibited viral replication.
Armed with a better understanding of its role in immune function,
people began to acknowledge zinc as an essential mineral for human health.
Interest grew even more after a 1984 study found that zinc lozenges may be useful for treating colds,
but trials since then have yielded mixed results.
But a meta-analysis submitted in November of 2020 might help close the gap of understanding zinc’s potential benefits.
Researchers looked at 28 randomized controlled trials involving over 5,000 participants.
To get technical, they found that when zinc was taken to prevent respiratory infections,
participants had a 28% lower risk of developing mild symptoms
such as those you’d get with the common cold — sneezes, sniffles, scratchy throat —
and an 87% lower risk of developing moderately severe, flu-like symptoms, like a fever and all those aches and pains that make us feel lousy.
If you already have a cold, using zinc to treat it was found to clear up symptoms two days earlier
and reduce their severity at the peak of illness,
but overall, you’re not in the clear,
as they found that the day-to-day symptom severity remained the same.
So how does zinc affect our immune response, anyway?
The immune response is divided into two parts: innate and adaptive immunity,
and zinc plays a role in both.
When infectious viruses or bacteria manage to invade the respiratory tract,
the innate immune system is the first line of defense.
It responds by sending out white blood cells to identify and eliminate the threat.
Zinc is vital for the normal development and function of these cells.
Our adaptive immune response, on the other hand, relies on the memory of specific infectious invaders in case they return.
B-cells manufacture antibodies to attack germs, and T-cells destroy cells infected with a virus…
both of which are activated by zinc.
When you're looking for zinc supplements, you’ll probably come across lozenges, pills, and nasal sprays,
all of which the latest meta-analysis looked at.
But there’s so much variation between brands and their individual dosages,
and not enough evidence to say definitively what works.
Some zinc formulations even contain ingredients that undercut zinc’s effectiveness.
For example, certain lozenges contain citric acid, which binds to the zinc in a way that prevents the mineral from being released.
And while zinc supplements are accessible and convenient, it doesn’t mean they’re risk-free.
Even moderate doses can produce minor side effects like nausea, stomach cramping, and even a sore mouth.
Taking high doses for a long period of time could even lead to more severe symptoms like copper deficiency.
That’s because zinc and copper compete for absorption in the stomach
and taking too much of one leads to a deficiency in the other.
So there’s a lot to consider this winter season — some zinc may help, but maybe don’t rely on it entirely.
When it comes to fighting colds, the best approach may be to not over-zinc it!