Zinc is considered a trace element. Even so, being present in only trace quantities does not denote a lack of its clinical significance in the body.
Zinc is involved in numerous body processes and acts as a co-enzyme or catalyst in many reactions such as – immune cell production, neurotransmission, the methylation pathway, detoxification, the production of NAD, and glutathione synthesis, just to name a few.
In essence, zinc is involved in many essential metabolic pathways, as more than 200 enzymes containing zinc have been identified.1
The importance of zinc in immune health has given rise to the popular zinc lozenges sold in stores that are marketed to help boost the immune system for people suffering from the cold or flu.
Zinc is required in the metabolism of protein in which the amino acids resulting in protein metabolism is used in the synthesis of lymphocytes that are used in the immune system to fight infection.
Since zinc is also involved in the methylation pathway and is used as a co-factor in making energy along with the B Vitamins, it is surprising that the marketed energy supplements use caffeine instead of adding zinc in their products.
Most of us are lacking in zinc even though the average consumption meets the Daily Recommended Intake which has many widespread implications in achieving optimal health such as stunted growth, poor wound healing, hair loss, diarrhea, skin irritation, and compromised immune function.1
The biggest reason for zinc deficiency is due to the lack of absorption, not to the lack of dietary intake as several factors can affect absorption of zinc.1 Low gastric pH is best for the absorption of zinc, but many people have an inappropriate pH level in the stomach to allow proper absorption of zinc.2 Foods can also have an impact on the amount of zinc available.
The processing of food, dietary fiber, other vitamins and minerals that compete for absorption with zinc, and the reduced consumption of animal products in our diet which is a rich source of zinc can all have a negative impact on the availability of zinc for absorption.1
The current RDA for zinc for males and females over age 14 are 11mg/day and 8mg/day respectively. Adequate intake for infants is 2-3mg/day up to age 3. Then 5mg/day for ages 4-8. Females ages 14-18 and who are pregnant have additional needs because zinc is used in building tissue in protein synthesis. Pregnant women need to have an intake of at least 11mg/day and 12mg/day during lactation for proper fetal development.1
There is a rare genetic disorder called Acrodermatitis enteropathica that results in the inability to absorb zinc from the intestinal mucosa. In these patients, if they are diagnosed early and given very high doses of zinc then they can avoid the serious complications of the disease of skin lesions and a compromised immune system.
Many factors need to be taken into consideration as to whether a person would benefit from zinc supplementation. I would recommend first to assess the pH of the gastric system. This can be done easily and inexpensively by purchasing pH strips and testing the saliva. I would instruct the patient to put a piece of pH test strip in their mouth first thing in the morning and note the pH. A normal salivary pH is around 6.4 before a meal. Then have breakfast, wait an hour and retest. If the pH is higher, around 8.0 then it is safe to assume a normal pH of the stomach, as the pH rises after a meal. If the pH does not go at least one point higher one hour after a meal than it was prior to the meal, then they most likely have an impaired HCl production in the stomach. I would then recommend on taking at least 40mg zinc along with HCl pepsin or HCl Betaine Also, they would benefit from taking the HCl pepsin/betaine with each meal to help with protein metabolism and absorption of other vital minerals nutrients that are pH dependent.
I also recommend that vegetarians take a zinc supplement, as animal food sources are the best sources of zinc, and the amount that is present in vegetables may not be bioavailable due to the binding of minerals to phytic acid.
I like pushing the intake of vitamins and minerals to the “upper limit” as it’s always best to have plenty of these nutrients available to perform their necessary tasks rather than risk a deficiency.
- Nix, S, (2013) Williams’ Basic Nutrition and Diet Therapy (14th Edition), St. Louis, MO, Elsevier Mosby, Chapter 8.
- Henderson L, Brewer G, Dressman J, etal. Effect of Intragastric pH on the absorption of oral Zinc acetate and zinc oxide in young healthy volunteers. JPEN J Parenter Enteral Nutr. 1995. Sept-Oct:19(5):393-7.