Most people would like to improve their immune function at this time of year. Viruses that cause colds and influenza are everywhere and even vigorous hand washing may not protect you from coming down with an upper respiratory tract infection. Could extra zinc help?
Zinc and Immunity:
Zinc is one of those minerals that gets very little respect. People often take calcium and magnesium, but rarely even think about zinc. Yet this mineral is crucial for the immune system. It activates T cells, which are crucial for combatting bacterial and viral infections. Your natural killer cells cannot function fully without adequate levels of zinc.
A research team from Tufts University recruited 25 older people who were low in zinc to participate in a double-blind, placebo-controlled study. The research was published in The American Journal of Clinical Nutrition (online, Jan. 27, 2016). It demonstrated that supplementing older residents in a nursing home with 30 mg of extra zinc daily for three months raised zinc levels in the bloodstream.
In addition, the investigators found that the group that got 30 mg of zinc compared to placebo (5 mg. of zinc) had better immune function. The number of T cells in their bodies went up, a measure of immune system enhancement. The T cells seemed more responsive in that they were able to proliferate more effectively in response to stimuli that simulated infection.
The Consequences of Low Zinc Levels:
The authors of this study had previously discovered that older people living in nursing homes frequently have low levels of zinc in their bodies. When this crucial mineral is deficient, there is a greater likelihood of developing pneumonia. The death rate is also higher when people are low in zinc.
Who’s At Risk of Low Zinc?
Nursing home residents are not the only people with low zinc levels. Older people in general may be more vulnerable to this mineral deficiency. One suggestion is that senior citizens have trouble absorbing zinc as well as younger people. Vegetarians may also be a greater risk of zinc deficiency. People taking blood pressure drugs that contain diuretics (hydrochlorothiazide for example) or ACE inhibitors (such as captopril, enalapril or lisinopril) could also be low in zinc.
The recommendation that our colleague Tieraona Low Dog, M.D., suggests is 15 to 25 mg of extra zinc daily for those on diuretics or ACE inhibitors. The Tufts researchers gave their older nursing home residents 30 mg daily. We would discourage anything over that since too much zinc can be toxic. The upper limit is 40 mg daily.
Which Vitamins and Minerals Should You Be Taking?
If you would like to know more about which supplements you should be taking to counteract medication depletion, we highly recommend a brand new book by Dr. Low Dog titled Fortify Your LIFE: Your Guide to Vitamins, Minerals and More. It is just out and we think it is the best and most up-to-date analysis about which dietary supplements are essential for good health. Dr. Low Dog makes sense out of what has been total confusion. Here is a link to her book, Fortify Your LIFE.
If you find this whole topic of interest, you will want to listen to our interview with Dr. Low Dog that airs this Saturday on our syndicated radio show. It will be available for downloading as an MP3 file on Monday. You can also order a CD along with the book.