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Winter Wellness with Quercetin & Zinc

Posted on May 1, 2021

Winter Wellness with Quercetin & ZincDividerimage

By Gavin Deguara, Naturopathy & Nutrition Medicine


Have you wondered why you’re more likely to get sick in winter? Though it’s something we take for granted, when pressed most fall short in offering a logical explanation.


Understandably so. It's probably not something you stay up late thinking about.


It's a intriguing though, as our core body temperature remains relatively constant when we’re in a cold environment, somewhere around the 36.5 to 37.5 degrees Celsius mark.


And if it starts to drop, we shiver. The muscle contractions generate more heat. So how are invading micro-organisms able to take advantage during the colder months of the year?


As it turns out, the temperature of our lungs can differ to our core temperature, just as our hands and feet may feel like icicles, even to the point that they turn slightly blue.


If we’re breathing in cold air, say at ten degrees Celsius, our lung temperature can drop significantly, even though our core body temperature may not change much at all.


If you’ve ever gone for a run early in the morning in the middle of winter, you’ll know exactly what this feels like. The air can be so cold it physically stings the lungs.


And this gives microbes a significant advantage. These invisible-to-the-eye micro-organisms thrive in the cool surfaces and areas of the human body, such as the lungs and nasal cavity1.


This has been proven scientifically, where a positive correlation has been shown between cold environments and respiratory tract infections2.


Viruses simply get more of a chance at success when we’re cold. This may be due to the fact that our natural immune system is suppressed by the cold as well, leading to poor defenses in the lungs3.




This may be due to constriction of blood vessels in the lungs that provide immune cells and nourishment.


But it’s not all about the temperature in winter. There might be other reasons we can get a little under the weather.


The Sunshine Vitamin

For instance, the sun travels at a more oblique angle in winter, just as it is during the morning and evening hours during any season.


This means the sun’s UVB rays have to travel through more ozone layer to get to us. As a result we need to spend more time in the sun to get our full complement of Vitamin D.


And if you’ve heard of this vitamin before, you’re probably aware that it acts more like a hormone in the body than a vitamin.


And it’s really, really important to our health.




Professor Holick has been leading the way in Vitamin D research for decades. If you haven’t heard of this awesome individual, it’s worth taking the time to listen to what he has to say.


This is the age of taking your health into your own hands. Careful dietary planning, exercise, stress management, adequate sleep and supplementation can make all the difference.  



If you’ve done any research on minerals before, you’re probably already aware that zinc is required for around 300 various enzymatic reactions in the human body.


Zinc is one of those super-crucial micronutrients, along with magnesium and vitamin C, that perform countless tasks in the human body.


Zinc is important for the health of both arms of the immune system: the innate and the adaptive. The innate immune system protects against foreign bodies, such as splinters, injuries and pathogens like harmful bacteria.


This mineral promotes healthy neutrophils and natural killer cell activity, essential to a competent innate immune system4.


The adaptive immune system is an antigen-specific response driven by the T and B Lymphocytes. For instance, an antibody is produced in response to an antigen on a foreign invader, like a virus.


Zinc is required for thymulin sythesis, which triggers the production of T-Cells (T Lymphocytes)5. The T-Cells are essential for the adaptive arm of the immune system.


This means zinc has got a finger in both “pies”. However, even these roles don’t capture the importance of this mineral to human health and the prevention of viral infections.




Zinc & Viral Replication

Zinc has the unique ability to not only support our natural anti-viral immunity by promoting healthy innate and adaptive immune systems, but to also offer specific anti-viral effects independent of the immune system6.


pepitas.jpgZinc offers a range of benefits directly against viruses, such as free virus inactivation and intracellular interference with replication.


This means that zinc can inactive the viruses that it comes into contact with, as well as reduce the infectious burden within cells.


For this latter action to occur, zinc needs to get inside the cell. And to get it in there in appreciable quantities, we need to tap into the natural synergism found within nature and groups of natural phytonutrients called ionophores (more on this later).


How Common is Zinc Deficiency?

In developing nations, as many as 2 Billion people may be affected by zinc deficiency to the point that it leads to developmental issues7.


A study published in 2011 by Nutrition and Dietetics indicated that the at-risk group for deficiency in Australian and New Zealand are toddlers, adolescents, diabetics and the institutionalised elderly8.


More recently, in 2015 the Journal of Nutritional Sciences indicated that in Tasmanian adults, 15% of men and 7% of women had low serum zinc levels, while 30% of men greater than 70 years had low levels9.


The 2015 study should be taken with a grain of salt, however, as most zinc is not found in the blood or plasma, which constitutes only 1.5% of the body’s content.


Approximately 86.2% of the body’s zinc pool is found in muscle and bone, with 3.4% in the liver and around 4.2% in the skin10. As is well known in the field of nutrition, blood or serum levels typically only drop once these more significant pools become depleted.


Therefore, low serum zinc may be a great deal more significant than expected. And someone with normal serum zinc levels can still actually be deficient in this important mineral. An accurate assessment of this mineral requires intracellular testing, such as a red cell zinc test.


Another study published in 2017 looked at childhood dietary intake of zinc foods. The study concluded that 19% of children aged 8 to 15 years lacked sufficient absorbable zinc in their diet11.


Food Sources of Zinc (USDA)




Best Zinc Supplements

Based on published scientific research, the best forms of zinc to supplement with are zinc glycinate, zinc chelate and zinc picolinate. After this, zinc gluconate, zinc citrate and zinc sulphate are fairly decent12, 13, 14, 15.


What the Heck is an Ionophore?

And why do I really care?

An ionophore is a natural chemical that offers some interesting benefits as an ion carrier. This means it can bind an ion, like zinc, and release it.


What’s the significance of this?


Mineral supplementation is a tricky business. As we just examined, there are some forms of zinc that absorb well from the gut to the blood or lymph.


This means they have a high bio-availability.


But this doesn’t take into consideration the movement of this mineral from the blood into the cell, which is where we need it to derive the most benefit.


Now supplementing a high quality mineral over time means eventually enough will find its way inside the cell.


However, to ramp things up a little this is where ionophores step into the equation.


Ionophores naturally bind zinc in the blood and drop them off inside the cell, like a nice Uber ride.


And these ionophores occur in natural too, like EGCG found in Green Tea, Curcumin found in Turmeric, perhaps Bismuth, and Quercetin found in a wide range of foods, such as apples and onions 16.




And when zinc is supercharged into the cell, we get more benefits such as anti-viral effects.


But there is one more challenge to consider before we jump on the ionophore bandwagon.


We know about zinc bio-availability, such as zinc chelate, and how to get it into the cell with natural ionophores like Quercetin.


However, first we need to consider how well these natural ionophores get into the blood, where we need them?


Are they bio-available or do we need to take something with them to enhance absorption?


As it turns out, Quercetin, Curcumin and EGCG are poorly absorbed through the human digestive tract17.


This creates another set of difficulties when supplementing. That’s if you want to get the very best your of your supplement program.


So let’s look at some solutions …



Quercetin is a natural flavonoid, like hesperidin and rutin, found in a range of foods, such as apples and onions.


In USA, the average quercetin intake is around 15mg daily, with similar intakes in Japan18. In Australia, the most common dietary sources are black and green tea, onions, apples, broccoli, grapes and beans19.


This flavonoid offers a range of health benefits, including anti-inflammatory actions, anti-allergy, anti-viral, anti-bacterial and more potent antioxidant effects than Vitamin C or Vitamin E 20, 21.


If this doesn’t sound comprehensive enough, Quercetin may also offer anti-diabetic, anti-Alzheimer’s, anti-arthritis, wound healing and cardiovascular promoting benefits 22.


This makes Quercetin one of the most powerful natural compounds available.


However, there is only one little caveat with this flavonoid. And that’s absorption.


Quercetin is poorly absorbed from supplements, however, at around 2% due to its low solubility in water. To enhance absorption, it is best taken in phytosome (phospholipid complex) form or with bromelains or Vitamin C 23, 24, 25.


Because Quercetin is fat-soluble it is best taken with a fat source or a meal containing fat, such as avocado, nuts, butter or whole eggs.


Once quercetin enters the system in appreciable quantities, it is then available to reversibly bind zinc and carry it into the cell.


Food Sources of Quercetin 26


Quercetin Content per 100g Whole Food



Fennel Leaves






Chili Pepper









It’s important to consider when looking at food sources per 100 gram how much of that food you would actually consume in one sitting.


For instance, most people would only consume around 5 grams of a herb, while a fruit or vegetable will be consumed in much higher quantities.


This would put onions, spinach and kale at the top of the quercetin foods list, despite the herbs and spices having a higher content per 100g.



Quercetin and Zinc are powerful natural supplements when taken together and in the rights forms can produce synergistic results.


In particular, the effects of zinc are somewhat diminished without a natural ionophore present, such as an appropriate quercetin supplement as previously discussed.


Alternatives to quercetin offering natural ionophore effects are a couple of cups of high-grade organic green tea to provide EGCG, or a tablespoon of a high-curcumin content turmeric powder mixed with organic black pepper, ghee and raw honey or an appropriate quercetin supplement.


Quercetin and zinc are supplements that many use year round to promote optimal health and prevent deficiency, respectively.


Certainly, the winter months or the year are more optimal times to stick to supplementation or these two important nutrients, given their natural anti-viral, anti-bacterial and anti-inflammatory effects.


Though there is no established Recommended Dietary Intake for Quercetin, don’t underestimate its importance.


For a general health maintenance, most people can supplement with 25mg elemental zinc once daily, taken with an ionophore, such as quercetin.


A maintenance dosage of Quercetin is around 500mg once daily, in a supplement containing Vitamin C or Bromelains. If you are using a quercetin phospholipid complex (phytosome), 250mg once daily will be plenty.


You may like to simply supplement through the colder months of the year, or year round to prevent deficiencies and support wellness.