Zinc & Health
It’s the end of the nutrients as we know them! If you have missed out on any of the previous 48 articles in this series, you can catch up using this handy index. As you can see, we have covered a lot over the past 14 months! My hope was to create an up-to-date reference for my own use and the use of others who are interested in knowing what the best available evidence says about nutrition and health. Nutrition is one of our fundamental ingredients for long-term health. It isn’t the full story, but it is a pretty important plot line! We really are made up of what we absorb from our food. Without further adieu, let’s wrap this chapter up with zinc.
What is Zinc & What Does it Do?
Zinc is yet another non-metal mineral that is needed for all forms of life. Like the other minerals, it comes from the crust of the Earth and makes its way into us through our food. Genetic research shows zinc interacting with over 300 different molecules in the body! Some of zinc's major impacts are in growth, development, and immune function.
Zinc Deficiency:
In resource-rich countries like the United States, zinc deficiency is relatively rare. When it does occur, it is due to illness, malnourishment, or a genetic disorder known as acrodermatitis enteropathica. In this last case, severe zinc deficiency that requires life-long zinc supplementation occurs.
The symptoms of acrodermatitis enteropathica include “slowing or cessation of growth and development, delayed sexual maturation, characteristic skin rashes, chronic and severe diarrhea, immune system deficiencies, impaired wound healing, diminished appetite, impaired taste sensation, night blindness, swelling and clouding of the cornea, and behavioral disturbances.” (1)
That is a long list of symptoms affecting many different systems and functions. Looking at this list helps us understand just how important zinc is.
When undiagnosed, acrodermatitis enteropathica leads to early death. Milder zinc deficiencies can result in impaired physical and neuropsychological development as well as decreased resistance to infection. (1)
Increased Risk of Zinc Deficiency: (1)
Premature infants
Low birth weight
Children and adolescents
Malnourished individuals
Pregnant/nursing individuals - especially adolescents
Those with malabsorption syndromes
Those with inflammatory bowel disease
Those who abuse alcohol
Those with chronic kidney disease
Those with sickle cell anemia
Those using zinc depleting medications
Older adults
Vegetarians
Where to Find Zinc:
Zinc is found abundantly in animal flesh and seafood. Zinc is also found in plant foods such as grains, legumes, nuts, and seeds. However, bound to phytic acid, zinc from plant sources is less absorbable than zinc from animal products.
Daily Intake:
Adults can avoid zinc deficiency by consuming a minimum of 8-11 mg of zinc daily. Pregnant individuals should aim for 11 mg daily, and those who are nursing need 12 mg daily to avoid deficiency in themselves and the child(ren) they are supplying with breast milk.
Copper deficiency results from excess zinc intake, but it can be avoided when zinc levels do not exceed 40 mg daily. As a reminder, the symptoms of copper deficiency are also significant and include:
Anemia
Lowered innate immune function
Low neutrophil count
Osteoporosis - more common in infants and young children
Loss of pigmentation
Neurological symptoms
Impaired growth
Central nervous system demyelination
Polyneuropathy
Myelopathy
Inflammation of the optic nerve
Changes in the bone marrow
Reducing Phytates in Plant-Based Foods:
Phytic acid and other phytates are the storage form of phosphorus in grains and legumes. These molecules are also known as “anti-nutrients,” as they can bind to essential nutrients, such as zinc, making them difficult to absorb. This is a problem for those of us who do not eat animal products. It is an even bigger problem world-wide in areas with lower access to resources like multivitamins, fortified grains, or simply enough to eat. In fact, zinc deficiency is estimated to cause 4.4% of global childhood deaths! (1)
Fortunately, there are things we can do in our kitchens to remove phytates from foods and increase the bioavailability of nutrients in plant-based foods! (2)
Soaking grains, legumes, nuts, and seeds - up to 25% reduction
Soaking and then cooking - increased reduction vs soaking alone
Sprouting - up to 40% reduction
Fermentation - up to 88% reduction
Soaking should take place at room temperature and last 12-24 hours. The soaking water will contain some of the minerals, proteins, and other water-soluble nutrients and should also be used if possible. The phytates will be broken down in the water, and are no longer of concern.
Toxicity:
Acute zinc toxicity is rare and has occurred in isolated events involving food or beverages improperly stored in galvanized containers. In these cases, zinc has leached from the containers and into the foods. This resulted in very high doses of zinc in the food - hundreds of milligrams!
Symptoms of Zinc Toxicity:
Abdominal pain
Diarrhea
Nausea
Vomiting
Prevention of Disease:
Consuming the RDA of zinc can be helpful in preventing the following conditions:
Pregnancy complications
Growth retardation
Delayed mental and psychomotor development in young children
Infectious diarrhea in children
Pneumonia
Malaria
Type 2 diabetes
Treatment of Disease:
Zinc also plays a role in the treatment of diagnosed diseases such as:
Wilson’s disease:
Zinc supplementation has been used successfully in the treatment of Wilson’s disease which is a disease of copper accumulation.
The Common Cold:
Zinc lozenge supplementation taken within the first 24 hours of infection, and again every 2-3 hours while awake, speeds recovery of the common cold reducing the duration of illness by up to a third. However, zinc supplementation does not ease those cold symptoms. When taken for 2 weeks or less, doses of 60-80 mg do not lead to copper deficiency. Keep this treatment limited to no longer than 2 weeks to avoid trading one issue for another. (1)
It should also be noted that not all over-the-counter zinc supplements are created equal. Avoid products that contain magnesium, amino acids, or citric acid - these can deactivate the zinc making it a waste of your resources and time. Also, do not use nasal zinc; this can result in permanent loss of smell! (1)
Age Related Macular Degeneration
The progression of this condition may be slowed with the use of zinc coupled with antioxidants like vitamin A and vitamin C. You could also take a good quality multivitamin. (1)
Diabetes:
With type 2 diabetes, the RDA of 8-11 mg of zinc is encouraged. For gestational diabetes, 30 mg of zinc for 6 weeks has been shown helpful in reducing blood sugar and triglyceride levels. (1)
Medication and Nutrient Interactions:
Zinc interacts with quite a number of different substances.
Zinc is involved in the activity of vitamin A, folate, and iron. Calcium can inhibit the absorption of zinc when these two minerals are taken together just as it does with iron. As mentioned before, zinc taken above the tolerable upper limit of 40 mg daily, results in copper deficiency.
When it comes to medications, zinc can decrease the absorption of cephalexin, penicillamine, atazanavir, ritonavir, tetracycline, and quinolone antibiotics.
Medications that can deplete zinc levels include penicillamine, diethylenetriamine pentaacetate, sodium valproate, and diuretics.
Because zinc can lower blood sugar, those taking anti-diabetic medications should discuss supplemental zinc with their medical providers and develop a plan to avoid hypoglycemia before introducing a zinc supplement to their health plan.
Applications:
This week, I hope you take away the following key points about zinc:
Zinc is a very active and important mineral for our overall health and development.
Soak, cook, sprout, and/or ferment your grains and legumes to liberate their minerals from phytates!
Too much zinc leads to copper deficiency.
Do not stick zinc up your nose if you enjoy your sense of smell.
Thank You!
We have completed our journey through the ins and outs of nutrition. We began with overviews of dietary strategies, discussed common deficiencies, talked about macronutrients and micronutrients, and learned more about how our bodies work along the way. If you have missed any of these articles, please feel free to go back and check them out!
I will be taking a seasonal break from my weekly writings to focus on gardening and creating in my kitchen during the growing/harvesting year. I plan to return to weekly articles in November, and will switch to monthly newsletters until then. If you are interested, please sign up for my monthly herbal medicine workshops. Our next meeting will be on Thursday, March 10th from 6:00 - 7:30 PM. All classes are held via Zoom video.
If you have ideas for future article topics, please feel free to email me at dr.currey@herbsandhands.com with your suggestions and questions. Please also be sure to sign up for my newsletter, as I will continue communicating here and will share previous writings, interesting tidbits I encounter, and other items that bring me joy through the year.
To our health!
References:
Higdon, J, “Zinc” Linus Pauling Institute, 2001; last update: 2019; accessed February 22, 2022; https://lpi.oregonstate.edu/mic/minerals/zinc
Gupta RK, Gangoliya SS, Singh NK. Reduction of phytic acid and enhancement of bioavailable micronutrients in food grains. J Food Sci Technol. 2015;52(2):676-684. doi:10.1007/s13197-013-0978-y
