Zinc: How much should you take a day

Zinc is my current wonder mineral. It seems to be used all around the body. How much zinc do we need a day ? First up we have a graph of zinc intake vs zinc absorption.

This graph shows the absorbed intake along the bottom and the total loss of zinc from the body in the vertical axis.The one to one line is the dotted line running up from zero. This is the line where if all the zinc you ingested was then removed from your body.

One of the two solid lines is the combined male and female data, and the other line is the female data. You can see that they all seem to meet/cross over at approximately 3 mg of absorbed zinc. Now scroll down and have a look at the identical graph, just below the first graph, but with two colored blue and green triangles on it.  

 

In this graph, which is identical to the graph above, I have highlighted two regions. The first blue region is where the total amount of zinc lost is more than what you have ingested. Therefore you are losing zinc. Clearly over time you will run out and have serious consequences. The green triangle is were you excrete less than your input so you much have enough. From this the human minimum requirement needed is calculated to be approximately 3 mg absorbed a day.     

The logical question is then - how much zinc do I need to take, to absorb 3 mg. Well the graph that answers this is found below. This graph shows absorbed intake on the vertical axis. Drawing a line across, and then down, we can see that we need to digest approximate 9 mg of zinc a day to maintain body zinc levels.    

The good news is that most multivitamin/mineral preparations have 10 -15 mg of zinc, so you are likely getting enough. Of course my next question is what is the maximum zinc level absorbable? This graph below, shows the maximum absorbed is just under 5.5 mg a day. This is when the daily intake is at 25 mg. Likely if the intake continued to increase, then there would be slight increase in absorption.   

What is also good to note is that the zinc from supplements appears to be just as absorbable as zinc from other dietary sources.

It should be noted that this grahs levels are "steady state" that is the approximate same level every day. This is because the process of changing how much of the zinc the body absorbs is a relatively slow changing process. The exact "lead in" time, ie time for the body to change what percentage of zinc it is absorbing is days or a week or two.

Interesting enough when I found out I was exceptionally zinc deficient the lady doing the test was very surprised to find out I was on a good multi. From memory I was on 15mg a day. When I took an extra 15 mg a day, I noticed a distinct improvement in mood. Even though the last graph above shows that an extra 15 mg would have resulted in not much zinc improvement, it was very important to me! I then moved onto 50 mg zinc tablets, but took them only when I "felt" I needed them (sniff test of jar). I no longer need extra zinc above my multi, so no longer take any extra zinc.   

Reference .