- that is the common thread in most chronic diseases
Lack of dietary zinc may disrupt the immune defense and increase your risk of inflammation, which is the common thread in most diseases such as eczema, rheumatism, diabetes, and cancer. Zinc’s underlying mechanisms used to be relatively unknown, but a new study published in the science journal Immunology shows that zinc regulates the white blood cells of the immune system plus the formation of various proteins that are important for controlling inflammatory processes. Unfortunately, zinc deficiencies are widespread for a number of reasons.
Zinc supports over 1,000 enzyme processes, many of which are directly or indirectly linked to the cells and proteins of the immune system. The innate immune defense works as storm troops and garbage collectors. It consists of macrophages that can destroy most germs and toxins without us ever noticing. If the task is too demanding, the macrophages signal the special troops – the T cells and B cells – for help. The production and instruction (training) of white blood cells take place in various parts of the body such as the bone marrow, the thymus, the spleen, and the lymph nodes.
It is always essential for the immune defense to attack directly and swiftly and to retract, once it has eliminated any threats such as pathogens or other intruders. Otherwise, there is a risk that the infection drags out or that the immune system overreacts, causing undesirable, chronic inflammation.
Many chronic diseases are characterized by mild, chronic inflammation that is unnoticeable. Still, chronic inflammation can be very harmful, as it constantly bombards the body with free radicals that can attack healthy cells and tissues.
Zinc deficiency takes its toll on T cells, macrophages, and proteins
In the new study, the scientists looked at the relation between certain macrophagic subgroups (M1 and M2) plus the so-called T helper cells that are the conductors of the immune defense. The researchers studied spleens from rats that had either been fed a standard diet with adequate amounts of zinc or a zinc-depleted diet. The rodents were then then divided into four groups:
- One group got a standard diet with plenty of zinc for six weeks
- One group got a diet without zinc and received saltwater injections three times weekly
- On group got a diet without zinc and received three weekly injections of interleukin-4, which stimulates and activates T and B cells
- One group got a zinc-depleted diet for six weeks followed by a standard diet for another four weeks
After studying the spleens of the zinc-deficient rats, the scientists observed a drop in the number of macrophages (M2), T helper cells (CD3+) and T killer cells (CD8+) plus GATA-binding protein 3 (GATA3), interleukin-4 and interleukin-13-positive cells. Meanwhile, levels of pro-inflammatory proteins like interleukin-1β and a protein called 1α (MIP-1 α) had increased significantly.
In the spleens of rats with sufficient zinc, on the other hand, the number of macrophages (M2), T helper cells (CD3+) and T helper cells (CD8+) plus GATA-3, interleukin- and interleukin-13-positive cells had increased.
The scientists explain that zinc deficiency leads to inflammation because it derails the T helper cells. However, too little zinc can also cause inflammation because it induces loss of important proteins such as GATA-3, interleukin-4 and anti-inflammatory macrophages (M2).
The scientists also stress the importance of treating zinc deficiencies with injections of interleukin-4 to counteract these undesirable inflammatory processes. Zinc is also an important antioxidant that counteracts oxidative stress caused by free radicals.
Zinc deficiencies are common
We get zinc from fish, shellfish, meat, dairy products, nuts, kernels, and beans. Animal sources are absorbed better than plant sources.
An estimated 12 percent of the US population lacks zinc, and 40 percent of the deficiencies are found among older people. Similar figures are likely to be found in European countries.
Zinc deficiencies can be the result of an unhealthy diet, lack of animal protein, large consumption of calcium, too much alcohol, aging, celiac disease (gluten intolerance), diarrhea, diuretics, birth control pills, prolonged use of antibiotics, and copper poisoning (copper and zinc are mutual antagonists).
Organic zinc supplements are utilized the best
It is best if you can get the zinc you need from your diet. When taking supplements, beware that many products contain inorganic zinc sources like zinc sulfate and zinc oxide, which the body cannot absorb all that easily. Organic zinc sources like zinc gluconate and zinc acetate, on the other hand, have good bioavailability. Read the label carefully to see what the product contains.
Kido T et al. Inflammatory response under zinc deficiency is exacerbated by dysfunction of the T- helper type 2 lymphocyte-M2 macrophage pathway. Immunology 2019 Apr.
Scott A et al. Zinc is a potent and specific inhibitor of IFN-ƛ3 signaling. Nature Communications, 2017
Ananda S Prasad. Zink in Human Health: Effect of Zink on Immune Cells. Molecular Medicine 2008
Lothar Rink. Zink and the immune system. Cambridge Core. Published on line 2000
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