Zinc and Cancer Prevention

I have always absolutely loved exploring the properties of specific foods. I remember coming across Mary Shenouda’s “Phat Fudge” a few years ago, and she very specifically stated that certain foods (like using Tahini instead of Almond Butter), and the turmeric, the cinnamon, all served very specific purposes. I’ve found the more I explain the benefits of certain foods and spices to my clients (or the potential harm - eg nightshades and the potential interaction with autoimmune-type symptoms), it makes it EASIER for my clients to accept temporary (or permanent!) food modifications.

Today I want to explore zinc more in depth in relation to cancer prevention/anticancer properties. As a root cause based practitioner, I wanted to first review the importance of zinc as foundational support, most importantly, for our digestion. One of the biggest issues within the Standard American Diet and the Pharmaceutical Industry is a misapplication of Proton Pump Inhibitors, Antacids, etc. Often these symptoms of reflux, GERD, etc, are due to stomach acid being too LOW (not being too high!). When stomach acid is too low (or if we continue to suppress it through medications), zinc is one of the common minerals found in food that cannot be absorbed properly.1 Zinc plays such a critical role to our overall health, that this is a big deal. (Not to mention the trickle down effect of low stomach acid - if food isn’t broken down appropriately, more than likely we will end up with leaky gut syndrome (or another gut issue), which weakens the immune system, making us more susceptible to cancer!) Zinc helps keep our cell membranes stable (necessary for anticancer benefits) and also supports the immune system, which is why so many look for Vitamin C plus zinc when the flu comes around! (However, supplement quality is important, and must not be overlooked). Zinc can often be a supplement that aides in improving stomach acid levels, and aids in tissue repair, so clearly we know zinc is incredibly important.

But what about cancer specifically? Dr. D.K Dhawan cites zinc as an essential mineral for regulating “oxidative stress, DNA replication, DNA damage repair, cell cycle procession, and apoptosis”2. Functional apoptosis is critical in avoiding cancerous cellular development. He also cites that zinc is safe, even at higher levels, making it a potentially huge benefit to preventing or reducing malignancies. As zinc isn’t stored in the body, we have to continually consume it from nutrient dense whole foods (ideally). He also goes on to explore the impact of zinc on p53, citing that zinc is responsible for the structure of p53 proteins, which in turn control tumor suppression.

Cardiff University looked specifically at the correlation between zinc and breast cancer in a 2012 study, actually citing that too much zinc would impact cell death/apoptosis just as much as too little (we’ll revisit why in a bit)3. This article went more into depth about the functionality of zinc, tying it to zinc transporters called ZIP7, which controls the amount zinc flowing in and out of cells. Essentially they found that patients with tamoxifen-resistant breast cancers had higher levels of zinc and ZIP7, tying it to malfunction of CK2, a protein which opens ZIP7. It is thought that drugs acting as CK2 inhibitors could block the release of zinc could also block development of cancer.

However, there may be another approach worth exploring. We know that minerals in the body must co-exist within a specific balance. zinc and Copper have 1:1 relationship, meaning that as one increases, the other typically decreases. While normally I would consider something like breast cancer to be potentially tied to estrogen dominance, this example above shows that may not always be the case. In estrogen dominance, you typically see estrogen bound to copper, and stored in the liver, and as the binding keeps the liver from properly flushing excess estrogen, it creates estrogen dominance. However, if it is in fact zinc that is too HIGH within the body, carefully monitored copper supplementation may be worth considering.

Yet another article published in 2019, “Association between serum zinc levels and lung cancer: a meta-analysis of observational studies”, explores the levels of zinc in relationship to lung cancer4. Both zinc AND copper were cited as potential deficiencies in regard to lung cancer cases they reviewed. But how can both be low with the type of relationship copper and zinc have? While ratios should be in balance, BOTH can be way too low, having significant impacts on health. Some supplementation offers a combination (often with other minerals) to achieve adequate, balanced levels, but the results of supplementation may be best reviewed via testing such as Hair Mineral Analysis. The meta-analysis study looked at numerous publications, narrowing down the scope of focus, resulting in 32 studies that met the criteria for the analysis. Of those 32 studies, 27 studies showed zinc serum levels lower in lung cancer patients. As lung cancer is often tied to smokers, etc, this also makes sense based on the impact smokers have on their stomach acid levels (separate study, but accurate information - Why Stomach Acid is Good For You1 briefly touches on smoking and stomach acid levels).

There are numerous studies that continue to explore the relationship between Zinc and Cancer, but again, going back to foundations -- if stomach acid levels are lower, and zinc absorption and utilization is impacted, and we know the role zinc plays in key functions like DNA damage repair and apoptosis, we can intelligently say that assessing zinc levels is critical for both cancer prevention and anticancer protocols. Thankfully, within my practice I’ve found an accurate method for assessing Zinc levels (without the turnaround time of labs) is the Zinc Taste test - simply swish Aqueous Zinc in their mouths for a full 30 seconds, while asking them to acknowledge (by nodding) if the solution tastes sweet, like water, if it tastes fuzzy or metallicy, etc. While several clients note a change around the 15-20 second mark from watery to minerally/metallicy, MOST clients complete the full test stating it only tasted like water, indicating a significant deficiency. While supplementation may be necessary, I still believe food sources are the BEST way to bring nutrient deficiency levels up, but this must be in combination with assessing gut health and digestive function.

So what are good sources of zinc? I like to start with assessing a Food Journal, and depending on the severity of diagnoses (which I don’t do!) or goals, we focus on “Trade and Upgrade” foods. One of my go-to resources is Sally Fallon’s original “Nourishing Traditions” book - when addressing the brief overview of zinc, she references good sources as red meat, oysters, fish, nuts, seeds, and ginger5. She also cites that sprouting grains, nuts and seeds (although I typically recommend at least a temporary elimination of grains), can neutralize the phytic acid found in the bran that normally inhibits the absorption of not only zinc, but calcium, magnesium, iron, and copper as well. I still recommend avoiding grains temporarily due to the inflammatory response, but at the very least, soaking and sprouting is better than nothing! It is important to note that the majority of highly bioavailable zinc is found in animal products, so vegan and vegetarian clients will need to be willing to either modify their diet (preferred) or agree to a whole foods based supplement such as Ancestral Supplements Organ Blend. Organ meats, particularly liver, are wonderful sources of zinc. I personally find that those that don’t like the taste of liver tolerate it better if it is spiced up a bit (I prefer Primal Palate’s New Bae Seasoning), assuming nightshades are tolerated. In addition, for those that find the texture less than appealing, blending liver into something like a soup or chili, or even blending it into scrambled eggs (also a great source of zinc! Eat the Yolks!) can help some overcome texture or taste disliking.

Other rich sources of zinc include: 100% Grass Fed Beef, Spinach, Asparagus, Mushrooms (Shiitake - a well cited superfood by Oncology Nutrition Institute!), Pasture Roaming Lamb, Sesame Seeds, Pumpkin Seeds, and the list goes on6. When considering food sources, whole real foods is best, ideally sticking with organic, soaked and sprouted seeds and nuts, and well sourced animal products, meaning wild caught (eg shrimp, salmon, etc), pasture roaming (your chickens, turkeys, etc), or 100% grass fed (like beef). If supplementation is required, the Nutritional Therapy Association suggests a quick dosing of Aqueous Zinc until a notable taste change occurs. The suggested dosing is 3-4 tablespoons of Aqueous Zinc (due to high absorption rates) a day, or up to half a bottle per day until taste is noticeably metallic or fuzzy. Other suggestions, such as one provided by Jonathan Wright in Why Stomach Acid is Good For You, include focusing on Zinc Picolinate (again, due to absorption success rates) with up to 30 mg per day, dependent upon the bioindividuality of the client. I believe supplementation can be necessary, but should always be used in combination with nutrient dense foods, with the longterm goal of limiting supplementation as a temporary booster and focusing on whole, real foods.

Due to zinc’s powerful impact on foundational health, the immune system, and the proven anticancer benefits through the impact of p53, and other functionality, zinc is critical to anticancer and cancer prevention. However, it should be noticed that excessive levels of zinc can cause a counterimpact, as noted in the study provided by Cardiff University3. We should always focus on utilizing techniques such as the Zinc Taste Test and Hair Mineral Analysis to ensure we are not OVER supplementing or increasing zinc levels. It MUST be in balance to achieve homeostasis and overall well being.

1. Jonathan V. Wright, Lane Lenard, “Why Stomach Acid is Good for You” (M. Evans 2001)

2. D. K. Dhawan, Vijayta D. Chadha, “zinc: A promising agent in dietary chemoprevention of cancer”, The Indian Journal of Medical Research, (December 2010), https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3102454/

3. Cardiff University. "zinc linked to breast cancer: Insight into body's zinc controls has implications for disease." ScienceDaily. ScienceDaily, 6 February 2012. <www.sciencedaily.com/releases/2012/02/120206102954.htm>

4. Wang, Y., Sun, Z., Li, A. et al. Association between serum zinc levels and lung cancer: a meta-analysis of observational studies. World J Surg Onc 17, 78 (2019). https://doi.org/10.1186/s12957-019-1617-5

5. Sally Fallon, “Nourishing Traditions: The Cookbook that Challenges Politically Correct Nutrition and the Diet Dictocrats”, New Trends Publishing, 2001.

6. George Mateljan Foundation, WHFoods.org, http://www.whfoods.org/genpage.php?tname=nutrient&dbid=115

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