CYP450 Enzymes: A Complete List of the Most Potent Inhibiting and Inducing Foods and Bioactives

I have been wanting to write this post for some time about CYP450 inhibitors: a complete list of the most potent inhibiting and inducing foods and bio-actives for some time. This information has made one of the biggest difference to my health and wellbeing and continues to do so.

It has become abundantly clear to me that the trigger of my mast cell activation was CYP450 mutations and prescription medication. I am also not alone as around 10% of the population have a similar mutation.

Interestingly Dr Theoharides in a recent presentation, confirmed that CYP450 mutations could be a trigger, and that flavanoids such as luteolin could be anti-therapeutic for these individuals.

Why? Because if you cannot metabolise a medication because of a CYP450 mutation then your body will treat it as a toxin, and there is strong evidence that toxins play a role in the development of diseases making an efficient detoxification system critical to good health and wellbeing.

Key Detoxification Pathways

The key detoxification, genetic polymorphism, and drug metabolism pathways are:

1. Phase I : cytochrome P450 enzymes,
2. Phase II : conjugation enzymes (that includes methylation).

Glutathione and antioxidants levels are key to both processes. It is a high anti-oxidant diet (rather than an anti-inflammatory) diet which is key to neutralising toxins.

Phase 1 CYP450 Enzymes

The CYP450 enzymes do the detoxification “heavy lifting” and are the first line of defence against toxins. An imbalance in phase 1 CYP450 enzymes can also impact on Phase II including methylation.

CYP450 enzymes are primarily located in the liver (although also in the kidneys, lung, and even the brain) and bio-transform the output of the gastrointestinal tract before passing the toxins to the kidneys.

There is a large degree of genetic variation in CYP450 enzymes. Only 50% of the population have a “normal” function of these enzymes. 40% have an altered function. 10% of the population have little to no function of at least one enzyme. I am one of those people.

A simple saliva test, such as DNA Dose, can tell you the precise function of individual enzymes. It is not enough to just do a 23andMe test as these results need to be interpreted.

Detoxifying Foods

Specific foods have been scientifically proven to influence our detoxification pathways.

The issue is not whether we should eat or not eat certain wholefoods. Rather current thinking is that we should eat a broad range of plant based whole foods, in a broad synergistic combination, to optimize detoxification. Based on clinical trials the cruciferous, allium, and apiaceous families appear especially important.

The following foods have been found to have an impact on the detoxification systems:

Foods Scientifically Proven to Detoxify infographic


Current research indicates that supra-doses of specific foods and bio-actives influence specific enzymes.

Many act in a dose dependent manner. At one dose they induce (increase the function) whilst at a different dose they inhibit (reduce the function) of the detoxification pathways. Other foods appear to be adaptogenic (balancing the function) of the individual enzyme.

This means that supra-doses of bio-actives may not be therapeutic. It may also explain why food forms of bio-actives are better tolerated than supplements.
A robust wholefoods diet remains the single most important way to detoxify.

Bio-individual Supplementation

Bio-active supplements may over-ride genetic mutations which may be contributing to a disease process. However, more research is needed in order to make conclusive bio-individual dosage recommendations.

Download my FREE ebook and find out which supplements impact which enzymes in which doses:

The use of supplements should be undertaken under expert supervision, against a background of a detailed medical history, and bio-individual SNP (single nucleotide polymorphisms).

Not all of these supplements will be either tolerated or successful. For example, I cannot tolerate quercetin or luteolin due to a CYP450 mutation, but I can tolerate and do exceptionally well on pycnogenol.

Again, 23andMe analysis alone does not meet these recommendations.

How to Use this Information

These tables provide a complete list of the scientifically proven CYP450 inhibiting and inducing foods and bio-actives. This area of research is an emerging area with much work yet to be done. It is best to rely upon clinical studies. It is difficult to extrapolate cell or animal studies precisely to humans.

However here are a few guidelines that are prudent based on the research are as follows;

1. Boost nutrition

Eating a broad range of wholefoods (with their synergistic benefits) is the most prudent way of improving detoxification. Research indicates that the amount of fruit and vegetables required for detoxification is around 10 serves a day of fruit and vegetables. The Wahl’s Protocol TM, with around 6 cups a day, would seem a good template, although it needs modification for food intolerances.

2. Reduce Toxins

A double-pronged approach (of boosting nutrition whilst reducing the toxic load) is also prudent.

Toxins include a wide range of items produced by the body not just foods and medications. I will shortly be writing another blog post outlining the key toxins which can trigger mast cell issues (mine was CYP450 mutations against a background of histamine intolerance) and how to diagnose the issues.

It is not enough just to boost nutrition. Any food allergies should be eliminated and food intolerances reduced to the threshold.

3. Bio-individuality

Based on bio-individual enzyme function, supra-doses of nutrients could be used to induce (if a slow metaboliser) or inhibit (if a fast metaboliser), an enzyme to over-ride or regulate it. This should be done in conjunction with a functional medicine specialist in conjunction with functional testing.

4. Lifestyle Medicine

Restorative physical activity, sleep, and stress management are also important to our detoxification. Stress levels in particular play a highly significant role particularly in neurological inflammation.


As patients we have been trained to take a pill when we are sick. The temptation to take a pill can also be especially strong when food is making us sick.

The reality for me however, and also a lot of my clients, is that lifestyle medicine and food is the way out of these issues. A bio-individual diet has made a profound impact on my health and it can for you too.

Enjoyed This Post?
Sign up for Monthly Updates. Its FREE!
Print This Post Print This Post

  • Shelley

    This is wonderful! From my research, HIT and mast cell is often triggered by toxicity of some sort or another. Think, some healed by fixing methylation, some by high nutrient diet, another had copper toxicity, others reducing mold/VOCs, others gut healing – most of these issues all come back to toxicity of some sort. I just discovered the problem my family has had is from aluminum toxicity from reverse osmosis water (home and from Whole Foods). I can’t wait to pour over the article!

    • Yes Shelley; I have some detailed articles ready to go!
      Toxic shock turns on the gene
      Finding the SNP that is mutated, provides the work around
      Lifestyle medicine is the solution.
      Aluminium is a known mast-cell stimulant.
      We need to approach this as a bio-individual exercise and give the body what it wants. Enjoy!

  • Pingback: Glutathione: A List of the Most Potent Inhibiting and Inducing Anti-oxidant Foods and Bioactives - Alison Vickery()

  • Joanne McPhee

    Loving your articles Alison. Thankyou for sharing 🙂 and helping me get my head around it all!

  • Janice Taylor

    I am going to see a doctor at U of Chicago who deals w/mast cell disorders. I have a positive tryptase an Beta 11 Prostaglandin 24 hr urine test. My only symptoms was flushing and high blood pressure which started in June. I was started on a beta blocker in January of this year and had an bad reaction from bed bug bites over a 6 month period (2 episodes/prednisone tax) which may have been a trigger?
    Any testing you recommend for doctor? I currently on low dose Singular but am switching to a low dose calcium channel blocker which I’ve read is better for mast cell patients.

  • Ruth Vuela

    Hello Allisosn,
    Thank you very much with these amazing articles.They are helping very much in my own path. I have HIT and some MCAS syntoms although I´m still waiting for some test results.
    My first question is if with a 23andMe test I can have information about the CYP450 enzymes for trying to find out the cause of my current status.
    And the second question is about the above download link: it takes me to nowhere. I cannot download the list. Could you please tell me how can I have it?

    • Hi Ruth
      My pleasure.
      23andMe does not provide test results for CYP450. The genes it tests for are largely irrelevant genes. You can read about it here; If you are in Australia this test is $149. If you are in the USA insurance companies do pay for it.
      I apologies about the download (we have been updating bits of the website and moving download platforms. If you email me at I will email you it until it is up early next week.

      • Ruth Vuela

        HI again,
        Thanks for your fast answer…

        I´m writing from Spain. Just in the other side of the world. 🙂
        I think I´ve found the equivalent to DNADose here. Its called PGx Basic and it tests CYP2D6,
        CYP2C9, CYP2C19, CYP3A4, CYP3A5 and CYP1A2.
        Should that be enough? Anything missing?
        Thank you very much again…
        This feels like making a big and difficult puzzle with small and different pieces. And with your articles is like I´ve found 10 huge pieces at the same time.

        • Hi Ruth
          This was A HUGE part of the puzzle for me. It is for 10% or more of the population. PGX Basic looks good and that is more than enough. Can you let me know how much it costs (and whether it is covered by any sort of insurance) for the benefit of others. Just to let you know also that these genes also impact how we process supplements.

  • Bethany Brake

    Hello… I’m enjoying your materials, I downloaded the intolerance food list and also purchased the probiotics for histamine intolerance. I am having issues with high histamine and also have genetic influences – homozygous on the CYP450. I’m having trouble downloading via the link above – it says ‘not available’. Is is possible to email it? Thank you!!

    • Hi Bethany nice to hear from you. We have recently updated the guide and it appears this link has not been sorted so thankyou for letting me know I do appreciate it. You can download the link here;

      • Bethany Brake

        Thank you! Got it! 🙂 Much appreciated

  • Ladyofthelake22

    I just tried to download the free Insiders Guide to CYP450 nutrient inhibitors and inducers mentioned in the above post, but after I signed up, the download changed to a histamine intolerance food list. I have had my P450 pathway tested and don’t understand how to best apply my results. So would enjoy reading your guide. Thanks!

  • Charles Tooraen

    Hi Allison, I have been dealing with FQAD (Flouroquinoline Associated Disablity) FQ’s are a significant inhibitor of the CYP450 system. Ironically, this same system is what is needed to metabolize these drugs, so in some cases, there can be a toxic rise in plasma levels of these drugs, and the body stores them, to later be released, and causing major issues with collagen production, DNA mutations, Nervous system issues, etc. I am interested in seeing what foods can help “Restart” this CYP450 system.

    • Hi charles I am sorry to hear you are dealing with FQAD. I am very familiar with it. There is a free download above of the CYp450 inducers. You need to support your body as a whole though to recover. I do this through a structured approach based on about 5 lab tests. I hope that helps.

  • Andreia Franco

    Hello. I am really confused, as I’ve read several articles on Pubmed stating that inducing CYP1A1 might increase the risk of cancer: “this enzyme plays a key role in the bioactivation of procarcinogens and
    proteratogens, such as arylamines and polycyclic aromatic hydrocarbons
    (PAHs)’ ( “Importantly, elevated CYP1A1 activity through activated AhR in
    placentas of women smokers has been associated with pregnancy
    complications”. Why would anyone want to induce it? From what I’ve read, several supplements sold to “improve health” can actually be detrimental to it. I’ve recently started low dose (10mg) quercetin, for allergies. To my surprise, it also improved my constipation (did some research and found out it modulates

    Chloride Transport), but it made my hair fall a lot. I did some research again and discovered it is also an aromatase inhibitor – it inhibits the transformation of testosterone into estradiol! Another study found out quercetin is a potent xenoestrogen, inducing breast cancer ( Messing with these supplements, unfortunately, is too risky to be worth a try. Instead of preventing cancer they might cause it!

    • Andreia,

      This is a perfect example of why Dr Google is dangerous and why the trial and error of supplements does not work.

      The goal is to optimize the actual function – as it is involved in clearance of hormones. The clearance of hormones can be determined with a DUTCH test including phase 1 and phase 2 detoxification. Then to work with an experienced practitioner who can customize a protocol with the whole picture. This includes the whole picture – what substances you DO NOT want to take and what substances will help. I use foods a lot too. Quercetin inhibits CYP3A4 which in some instances is desirable and in other instances is highly desireable.

      Had you tested. You would not have undergone the cycle or trial and error.

  • Gee G

    Hi Alison. This is probably one of the most insightful and informative sites addressing such a specialised topic. I’m based out of Toronto, Canada and wanted to know if there are local or regional providers of the cyp450 polymorphism profile test.

    • hello I am not aware of a company in Canada itself. The US-based company that Dr. Afrin was using has just gone bankrupt. I will try and update the article when I discover another company in the USA. Please let me know if you find anyone locally.

  • Wendy Webster

    Hi Alison,

    Do you know any specialists on this in the UK?
    My husband has aspergilloma which is not responding to Itraconazole so that is now stopped and he’s awaiting consultant appt in a month. I think this is linked to the P-450 pathway??
    Got him on garlic capsules and turmeric but really not much idea what I’m doing diet wise!!
    Any suggestions gratefully received.