My name is Izzy; I hold a degree in Nutrition and Health from the University of Roehampton.
I create science-backed videos on supplements, nutrients, and evidence-based health topics.
Disclaimer: This content is for educational purposes only and does not substitute medical advice. Always speak to your healthcare provider before making changes to your supplement or diet routine.
In this episode, we take a look at three foundational supplements that may support immune health — particularly during cold, flu, and COVID-19 season.
We explore the evidence behind Vitamin D, Zinc, and Quercetin, focusing on their key mechanisms, synergistic effects, and what recent research says about their potential role in preventing or reducing the severity of respiratory viral infections.
What You’ll Learn:
⦁ How Vitamin D supports innate immunity and antiviral defences
⦁ Why Zinc is essential for immune cell function and viral inhibition
⦁ How Quercetin works as a zinc ionophore to enhance intracellular action
⦁ Research findings from peer-reviewed studies and meta-analyse
⦁ Key mechanisms, cofactor combinations, and practical considerations
Key Supplements Covered:
1. Vitamin D (with K2 & Magnesium)
2. Zinc (with ionophores)
3. Quercetin (antiviral & anti-inflammatory effects)
I have no affiliation with any of these companies but these are the ones I use as I believe them to be high quality:
Youth and Earth Vitamin D K2
Pure encapsulations Zinc 30 (picolinate)
Pure encapsulations Quercetin 250 x 2
In the evenings I occasionally also take by Lipolife Liposomal quercetin with Vitamin C.
00:00 – Introduction & Disclaimer
01:20 – Vitamin D
03:56 – Zinc
07:38 – Quercetin
10:23 – Final and closing thoughts
https://www.mdpi.com/2072-6643/12/7/2097
https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2021.799709/fullhttps://journals.plos.org/plosone/article?id=10.1371/journal.pone.0328232
https://pmc.ncbi.nlm.nih.gov/articles/PMC9864223/
https://pmc.ncbi.nlm.nih.gov/articles/PMC9864223/
https://ods.od.nih.gov/factsheets/Zinc-HealthProfessional/https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1001176
https://www.spandidos-publications.com/10.3892/ijmm.2020.4790
https://pmc.ncbi.nlm.nih.gov/articles/PMC5640865/
https://pubmed.ncbi.nlm.nih.gov/9823012/
https://pubmed.ncbi.nlm.nih.gov/17449604/
https://www.sciencedirect.com/science/article/pii/S1016847823002017?via%3Dihub
https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-025-06259-y
https://www.mdpi.com/1424-8247/15/3/377https://www.sciencedirect.com/science/article/pii/S2161831322004112?via%3Dihubhttps://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1001176https://www.sciencedirect.com/science/article/pii/S2095177921001106?via%3Dihub
https://onlinelibrary.wiley.com/doi/epdf/10.1002/ptr.7309
https://www.sciencedirect.com/science/article/pii/S2095177921001106?via%3Dihub
https://pubmed.ncbi.nlm.nih.gov/25050823/https://www.sciencedirect.com/science/article/pii/S0753332224010618https://www.mdpi.com/1999-4915/8/1/6https://www.mdpi.com/1424-8247/15/3/377
Hello all and welcome back. In today’s episode, we’re going to be exploring a supplement protocol for colds, flu, and CO. I would just like to state that before making any changes to your diet or supplement routine to please consult a health care professional and or your doctor. If you are taking any medication or are on any medication, please do not make any changes to taking your medication whatsoever. The information on this video is simply for educational purposes and is not and should not be substituted as medical advice. Now, throughout this episode, I will be referring to my notes a lot as I am reading several randomized control trials and I want to make sure that I’m getting the mechanisms correct and the trials correct and not confusing them having read them many, many times over. I hope this isn’t too complicated and I hope I’ve broken it down enough. If you have any questions or queries, please do leave them in the comments and I will try my best to answer them. So many people are coming to me saying that they’ve caught some kind of a flu or COVID and it is that time of year where virulence for these airborne viruses are very very high. So my aim of this video is to try and provide you with some supplemental tools that may help prophylactically or help shorten the duration of a cold, flu or COVID or lessen the symptoms. So the first supplement I’m going to be touching upon is by far the most key one out of the lot and that is vitamin D. Now I have touched upon vitamin D previously. Now vitamin D is not just a vitamin or a supplement. It is a steroid hormone that regulates at least 5% of the human encoded genome. Now it’s known to enhance innate immunity. It has antiviral properties, helps disrupt viral envelopes and it also helps with the secretion of immune peptides. So there was a meta analysis conducted of various randomized control trials that showed that vitamin D had a prophylactic effect against influenza. So it means it helped stop incidences, reduce instances of influenza or flu. Overall, it suggested that strategies for preventing influenza can be optimized by vitamin D supplementation. Vitamin D is prophylactic. Various studies also show that those with low levels of vitamin D were more likely to end up hospitalized with COVID 19 than those who had sufficient levels. Now, I have to say I would be really, really interested to know what a trial would show if vitamin D was combined with K2 and magnesium. Now, as we spoke in the first vitamin D episode, K2 helps with the absorption of vitamin D and sends calcium to the right places, and the magnesium helps activate the vitamin D. So, I would be really really curious to see what a trial results would show if they actually helped vitamin D function to the best of its ability. So, moving on to dosage, I would say prophylactically between 1,000 international units and 4,000 international units. Now, 4,000 international units has been set as the upper limit. You should always have a blood test done, check where your levels are, and discuss with your doctor. But those those doses are a great way to start prophylactically taking vitamin D. So timing wise, again, I would say all year round really. Again, have your levels checked and measured. Maybe you do need less in the summer if you’re getting lots and lots of sunlight. There are obviously precautions that should be taken there as well. But definitely in the winter months when there’s much less sunlight, definitely be taking prophylactic vitamin D. Now, just to mention, you should definitely take vitamin D and or indeed all supplements with a fatty meal. Vitamin D is a fats soluble supplement and should definitely be taken with fat. And remember, for better absorption, combine it with magnesium and vitamin K2. So, to summarize, vitamin D, vitamin D is a steroid hormone involved in regulating immune function and gene expression. It enhances the body’s innate immune response and may help defend against respiratory viruses. Studies suggest that it can reduce the risk of cold, flu, and COVID, especially in those who are deficient. Okay, so moving on to zinc. So zinc is an essential trace mineral that your body requires to carry out the majority of its functions. So when it comes to zinc’s immune properties against viral pathogens, zinc is essential for the activity of tea cells, natural killer cells and neutrfils and these are the most fagocyitic cells meaning they help engulf pathogens um which are all vital to the immune response and for responding to viral infections. Zinc also inhibits viral RNA dependent RNA polyamorases. So when intracellular concentrations of zinc is high, zinc can directly interfere with the viral replicase system of RNA viruses. So this reduces the viral RNA synthesis and prevents replication. So viruses essentially viruses don’t really want to kill people. They want to spread and mutate. Why? It’s not certain. So the key aim of viruses is to get into your cells and then basically become a photocopying machine and copy and copy and copy and copy and copy and copy and keep spreading. So when we discuss supplements and protocols and even pharmaceutical interventions, it’s to try and prevent and stop and interfere that replication process as that way you stop the virus pretty much dead in its tracks. Now there is a issue and problem with zinc and a pretty big one. So zinc is not easily transported into cells intracellularly at large amounts in order to inhibit viral replication. So it does need help getting inside the cell and becoming high in concentration intracellularly. So zinc hasn’t inherently shown to reduce incidences of cold and flu in trials, but has shown to shorten the duration and severity of them. Now the reason why I don’t think zinc showed a prevention in incidences of colds and flu was because it wasn’t combined with an ionor. So a zinc ionaphor is a substance that helps zinc ions cross the cell membrane and enter cells. so that they can perform their vital functions such as boosting the immune system and inhibiting the viral replication. So the reason why I don’t think zinc showed prevention in incidences of colds, flu, and covid was because it wasn’t paired with an ionophore in these trials. So because zinc has an issue getting an problem getting into the cell on its own, it does require an ionophore to help carry the charged zinc particles into the cells. This then increases intracellular zinc and thereby enhances the zinc dependent biological processes. So when it comes to zinc dosing, I personally take 30 milligs of zinc perkillinate a day and I do pair this with an ionaphor called keretin which we’re going to move on to in a moment. So between 15 and 30 mig of zinc, you can take citrate, you can take pillinate. I wouldn’t take elemental just because it’s not as well as absorbed as the other two, but I would definitely suggest either citrate or pcillinate. And I would take that daily just for immune maintenance. for acute use up to 75 mg of zinc lozenes it was mentioned in the literature can be useful with an onset of a cold or flu to help with the onset so you can take it timing wise just for maintenance but you can also take it with the onset of a cold or flu I would also just like to add that maintenance-wise 40 mg per day is the upper safety recommended amount anything more than that and you may become deficient in copper as zinc and copper compete for absorption in the So to summarize, zinc. Zinc is essential for immune function and plays a direct antiviral role by interfering with viral replication inside cells. It supports key immune cells like te- cells and natural killer cells. While zinc may not prevent colds and flu, studies suggest that it can reduce their their duration and severity especially when paired with a zinc ion to enhance cellular uptake. Moving on to keretin. Now I’ve briefly just touched upon keretin. So kirsten is is a polyphenolic flavonoid that exhibits broadsp spectrum antiviral activity through multiple mechanisms. It acts as an antiviral, antioxidant, anti-inflammatory and an ionophore. So as I previously said, keretin facilitates the zinc intracellular zinc uptake in cells. This then allows zinc to combat viral replication. So what happens is that keretin binds zinc and forms a complex that can cross the lipid billayer of the cell membrane. This then effectively increases the intracellular levels of zinc. So keratin also has very powerful um and potent anti-inflammatory. So keretin can reduce cytoine production for example intralucin number six or tumor necrosis factor alpha and inhibits also NFCappa. So it’s very very beneficial in respiratory infections particularly even co 19 related cytoine dysregulation does also have some antiviral effects on its own. So keretin has been shown to directly inhibit viral enzymes and interfere with virus entry and replication particularly in influenza particularly in influenza rhino viruses which is the common cold and corona viruses. So zinc plus keretin equals enhanced intracellular zinc which leads to the inhibition of viral replication. Okay, that’s the mechanism. So think of keretin that unlocks the door to let zinc into the cell where zinc that can then actually interfere with the virus. So with respect to keretin dosagsing long-term studies haven’t really been done. There aren’t many reports if any of toxicity from keretin or negative symptomology from taking ceretin. Generally the recommended dosage is 500 mg which I take prophylactically every single day. I also do in the evening take a further I think it’s 150 mig of liposomaal keretin so it enhances the absorption of the keretin in the evening but I would say that 500 mg is a great prophylactic starting point and you can probably move up to a gram so 1,000 mg of keretin during a cold flu or when you feel an early onset of a cold flu or virus make sure you take cursin with fat as it is fat soluble and also make sure to take zinc with it to get the full benefits it. So in summary, ceretin is a plant-derived flavonoid with antiviral, anti-inflammatory, and antioxidant properties. It also acts as a zinc ionophore, helping transport zinc into cells where it can inhibit viral replication. Research shows that kerin can help modulate the immune response and reduce inflammation. Can also directly interfere with the life cycle of certain viruses, including influenza and corona viruses. So vitamin D, zinc, and kerin are the foundational immune support supplements that I would recommend. They should not be a substitute for for a high quality bioavailable nutrient-dense diet or good sleep, hydration, and exercise regimens. Thank you very much for sticking with me through that video. I hope that was useful to you. I will catch you in the next one. And that was science made simple.
