
Zinc – Supplements for Psoriasis III

Why you should take zinc? – digestion, liver, immunity. Zinc is actually one of the most underrated supplements. Considering its vital function in many processes in the body just thinking about the deficiency of this extremely important mineral is frightening. Without zinc your body couldn’t live. However the three major functions that are linked to psoriasis are: digestion (assimilation of food, disinfection in the stomach), liver (detoxification, making proteins) and immunity (T-cells production and maturation in Thymus).
Digestion
Zinc plays a critical role in right stomach acid production (enzyme carbonic anhydrase). Also is needed for making digestive enzymes, bile production, repairing the leaky gut (intestinal wall). The thing is that for zinc absorption from food you need enough stomach acid. However since stomach acid production depends heavily on enough zinc in the body, you can get into the vicious cycle where the supplementation is required while your body will be able to produce enough stomach acid on its own.
Liver
Liver as major organ for detoxification of the body needs zinc every day and without it can’t do its job. There are many studies that conclude positive effects of zinc supplementation in liver diseases. Since zinc plays a role in bile production that way it affects the fat soluble vitamins absorption, fatty acids assimilation, flushing out the toxins and small intestine and colon healthy flora by damaging the bad bacteria.
Immunity
Along the other functions in immunity, zinc plays also the critical role in thymus development and maintaining its function. Thymus is a gland located above the heart and it is the place where the T-cells are matured and learned to know what to do in the body. Therefore zinc deficiency is linked to asthma, infections and slow wound healing. Some psoriatics even completely cleared up their skin taking the zinc supplement. I am not saying that many sufferers get well using just zinc supplement, but it is very important mineral which deficiency can manifest as psoriasis.
How to know if I am deficient?
Well there is no easy home test, but generally the loss of smell is considered as zinc deficiency symptom. Zinc is also depleted during stress, poorly absorbed in people with gastrointestinal problems, and many of those who need it more to repair the tissues in all chronic diseases. Today it’s probably more rare to find somebody who is not zinc deficient.
One thing are the RDA (recommended daily intake) doses in various countries which according to many studies and doctors show up as very low. The another thing is that if you count all the zinc content in standard diet you will find out that even the RDA dose is hard to achieve, not to mention that you need to absorb it from the food. Considering the impaired digestion and absorption in many people with some illness (not just psoriasis) it is clear that you may need to take some quality zinc supplement.
How much zinc should I take?
I think that the best way to correct the zinc deficiency is to take about 50 mg -100 mg of elemental zinc a day divided in two doses. The form seems to be best as zinc picolinate or zinc gluconate. The RDA doses for zinc intake around the world are about the 10-15 mg a day, so 100 mg a day is about the 7 times more than RDA what should correct the deficiency in about 1-3 months in most people.
If you would have a problem taking the 100 mg a day then you can try the half dose. Everybody is different and body can absorb and make use of just some of your zinc intake during the day. Therefore somebody can feel the difference in 2 weeks and the other maybe in 3 months.
Also it is advised to take some copper while taking zinc since high dose zinc intake can cause copper deficiency. Zinc overdose can manifest as many different symptoms so then it is the best to stop taking zinc and continue just with copper. The ratio zinc:copper is about 15:1, that means 50 mg of zinc a day and 3 mg of copper a day.
Since many psoriatics according to studies have higher levels of copper, many people use just zinc supplement to correct its deficiency and supply the body tissues with it.
Tip
If you have low stomach acid production then you can try to use about 3 Betaine HCL capsules about 10 minutes before taking zinc supplement for the best absorption of supplemental zinc.
Zinc Deficiency Causes Inflammation, Pain and Anxiety Not Only in Psoriatics
Zinc deficiency in psoriatics is well known and was confirmed by multiple studies. Actually when “380 patients with alopecia areata, alopecia androgenetica, psoriasis vulgaris, vitiligo, rosacea, venous ulcer and atopic eczema, [were] compared with 31 healthy people” the serum zinc levels were low in all diagnoses.[15]
Supplementation may be inevitable due to higher loss of zinc as well as possibly decreased assimilation due to intestinal inflammation and weak digestive capabilities of the stomach.[13,14] Another problem is a high intake of phytic acid containing foods like grains and legumes which significantly decrease the zinc absorption.[12]
This Zinc product is designed to resist the binding effects of phytic acid and dietary fiber.
Zinc deficiency in experimental human model caused “decreased serum testosterone level, oligospermia, severe immune dysfunctions mainly affecting T helper cells, decreased serum thymulin activity hyperammonemia, neuro-sensory disorders and decreased lean body mass.”[8]
Ammonia toxicity and Zinc
Ammonia is a strong neurotoxin which may cause a lot of health problems. Especially mental disorders because brain have limited capability for ammonia detoxification.
Increased levels of plasma ammonia and blood urea nitrogen (BUN) were reported in zinc deficient animals and humans.
Hyperammonemia which I believe is involved in a lot of cases of anxiety and diminished mental performance has been reported also in zinc deficiency.[9]
Hyperammonemia is usually ignored by the doctors in everybody who is better than with advanced liver cirrhosis and hepatic encephalopathy.
The positive effects of zinc supplementation on blood ammonia levels were confirmed in patients with liver cirrhosis. Patients received 150mg of zinc as zinc acetate in 3 divided doses daily for 3 months.[7]
Blood levels of zinc significantly increased in patients taking zinc and their blood ammonia levels significantly decreased. Blood ammonia levels significantly reduced at the eighth week of supplementation with zinc.[7]
Zinc supplementation may help prevent the hepatic encephalopathy (which is often caused by ammonia) by activating glutamine synthease enyzme.[10]
“
Serum zinc levels and its daily urinary excretion were measured, an oral zinc-tolerance test was performed to examine zinc malabsorption, and the effects of diuretics on zinc excretion and of zinc supplementation on ammonia metabolism in the skeletal muscle were studied. The mean serum zinc levels in patients with decompensated liver cirrhosis were found to be significantly lower than the levels in controls and patients with compensated liver cirrhosis. The serum zinc levels were inversely correlated with blood ammonia in the fasting state.
…
An increased uptake of ammonia by and an increased release of glutamine from leg skeletal muscle after oral supplementation of zinc sulfate were evident. Taken together, zinc deficiency in decompensated cirrhotic patients appears to be due to low absorption and to high urinary excretion, for which excessive diuretic administration is, in part, responsible, and zinc supplementation might play an important role in the prevention of hepatic encephalopathy by activating glutamine synthetase.
“[10]
Source: Yoshida Y, Higashi T, Nouso K, Nakatsukasa H, Nakamura SI, Watanabe A, Tsuji T. Effects of zinc deficiency/zinc supplementation on ammonia metabolism in patients with decompensated liver cirrhosis. Acta Med Okayama. 2001 Dec;55(6):349-55.
Zinc supplementation in rats with experimental cirrhosis proved to decrease the levels of plasma ammonia to normal levels and increased the liver ornithine transcarbamylase activity which is a key enzyme responsible for elimination of ammonia.[11]
“
Plasma ammonia level was significantly inversely correlated with liver ornithine transcarbamylase activity and positively correlated with serum and hepatic zinc content. Our results suggest that zinc deficiency may modify hepatic ornithine transcarbamylase activity and, therefore, ammonia disposal.
“[11]
Source: Riggio O, Merli M, Capocaccia L, Caschera M, Zullo A, Pinto G, Gaudio E, Franchitto A, Spagnoli R, D’Aquilino E, et al. Zinc supplementation reduces blood ammonia and increases liver ornithine transcarbamylase activity in experimental cirrhosis. Hepatology. 1992 Sep;16(3):785-9.
I have one previous article about the positive effects of L-Ornithine on ammonia toxicity which I recommend you to read.
Zinc for nervous system
I have found some interesting studies which found out that zinc acts as a positive allosteric modulator of the beta-2-adrenergic receptors. That means that the effects of agonist (activator) of beta-2-adrenergic receptors will be amplified thanks to zinc.
I think that in psoriasis it may be very beneficial to directly or indirectly improve the function (responsivity) of beta-2-adrenergic receptors.
The study from 2002 confirmed that physiological concentrations of zinc increased the agonist affinity (adrenaline is a major agonist) and increased the cAMP levels when stimulated by non-selective beta adrenergic receptors agonist – isoproterenol.
You can think about the isoproterenol as a synthetic chemical similar to naturally produced adrenaline.
“
We found that physiological concentrations of Zn(2+) increased agonist affinity and enhanced cAMP accumulation stimulated by submaximal concentrations of the betaAR agonist isoproterenol. These results provide evidence that Zn(2+) released at nerve terminals may modulate signals generated by the beta2AR in vivo.
“[1]
I have described the same mechanism on this blog in case of galantamine and how it affects the alpha-7-acetylcholine nicotinic receptor present in various tissues like in the brain but also on the surface of lymphocytes (type of white blood cells) where it acts as an anti-inflammatory receptor.
Great supplement which can significantly increase the cAMP levels is Forskolin which I wrote about here. Forskolin does increase the cAMP levels via different pathway than adrenaline so even if adrenergic pathways or receptors have some problems forskolin will bypass that issue and stimulate the cAMP production itself.
Zinc as anti-inflammatory supplement
Zinc is an anti-inflammatory agent and scientists researched its positive effects on endotoxin induced TNF-alpha production.[2]
Sadly, most of the studies about inflammation is targeted on immune cells even though nervous system is more important in inflammation than immune system itself.
First of all, with every supplement or a drug we should always look at its effects on nervous system because nervous system controls everything.
Zinc sulphate supplementation proved as effective in patients with rheumatoid arthritis. Joint tenderness, joint swelling, morning stiffness, walking time and subjective opinion of patients on disease all were improved after addition of zinc sulphate (220mg 3 times daily) supplementation for 12 weeks to patients’ pre-existing therapy.[4]
However, when zinc supplementation effects on plaque psoriasis were researched for 12 weeks there was no statistically significant improvement in PASI (psoriasis area and severity index) score nor neutrophil (a type of immune cells) zinc content.[5]
Even though the zinc sulphate supplementation did not affect the psoriasis severity it significantly improved the symptoms of psoriatic arthritis. The improvement was confirmed also biochemically by reduction of serum immunoglobulins and an increase of serum albumin levels. However, the same study concluded that improvement of psoriatic skin was was not seen.[6]
Let me know your opinion on zinc in the comments.
Psoriasis: How Zinc Deficiency May Be Actually An Omega 6 Deficiency
A deficiency of any essential nutrient (including the omega 6 fatty acids) may be the cause of every disease possible including psoriasis.
The problem is that people get often so hooked up with some idea that they stop thinking about the deficiencies logically.
A lot of “health gurus” are OK with fooling you and selling you the supplements over and over even though you did not improve even after months on them.
In this post I would like to show you that maybe that “zinc deficiency” is not always a zinc deficiency and it is actually the fatty acids deficiency.
But the similar scenario as I describe in this article is very possible in case of any nutrient including magnesium, calcium, iodine, B-vitamins and so on.
So even though I am striving on importance of B-vitamins for reversal of psoriasis keep in mind that low bile flow impairs the fat digestion dramatically so you may be very well deficient not just in omega 3 but even in omega 6 fatty acids.
I would say mostly omega 6 fatty acids since many psoriatics avoid them intentionally in order to decrease the production of inflammatory molecules which may not be the best idea. Not all omega 6 fatty acids are alike.
Zinc deficiency vs. Omega 6 deficiency
The Zinc deficiency and Fatty Acids deficiency both share these symptoms:
- dry skin, scaling, bumps
- weak nails
- visual symptoms (blurring, daylight/bright light sensitivity)
- excessive hunger
- weight loss
- impaired immune system (immunodeficiency, allergies) – inflammation
- mental disorders
Elongation and Desaturation Pathways for the Omega-3 and Omega-6 Fatty Acids
Image Source: Kruger MC and Horrobin DF. Calcium metabolism, osteoporosis and essential fatty acids: a review. Prog Lipid Res 1997;36(2/3):131-151.
Downloaded from: “Can Manipulation of the Ratios of Essential Fatty Acids Slow the Rapid Rate of Postmenopausal Bone Loss?” by Debra B. Kettler, MS, DC, (Altern Med Rev 2001;6(1):61-77)
The first study – “Most biological effects of zinc deficiency corrected by γ-linolenic acid (18: 3ω6) but not by linoleic acid (18: 2ω6)” – I am going to refer to in this article was published in 1982, but many of you probably never though or heard about something like this up to this day.
Just read the next abstract of the study “Most biological effects of zinc deficiency corrected by γ-linolenic acid (18: 3ω6) but not by linoleic acid (18: 2ω6)”.
”
Zinc deficiency mimics many of the clinical features of essential fatty acid (EFA) deficiency in rats. Since zinc appears to be needed for the Δ-6-desaturase step in EFA metabolism, experiments were conducted to determine whether bypassing this step with γ-linolenic acid (18 : 3ω6) would alleviate the biological effects induced by a zinc-deficient diet. In pair-fed rats over a period of 5 weeks the deficient diet impaired growth and changed the relative weights of internal organs. It also induced hypolipidemia but had little effect on the fatty acid composition of tissue lipids.Daily subcutaneous injection of primrose oil containing 10% 18: 3ω6 reversed most of the effects of zinc deficiency on tissue weights, growth and plasma lipids. In contrast, injection of safflower oil, which has a similar content of linoleic acid (18 : 2ω6) but is devoid of 18 : 3ω6, had only a partial effect on some tissue weight changes. Neither oil affected the plasma fatty acid pattern, but both of them increased liver triglyceride concentrations. They also elevated the proportion of 18 : 2ω6 in liver, skin and epididymal fat. The latter effects were not observed in the absence of zinc deficiency. Supplementing the diet of EFA-deficient animals with an excess of zinc in their drinking water did not affect the typical tissue fatty-acid pattern of EFA deficiency. It is suggested that several of the manifestations of zinc deficiency are mediated by a relative state of EFA deficiency attributable, at least in part, to a reduced conversion of 18 : 2ω6 to 18 : 3ω6 resulting in an accumulation of 18 : 2ω6 in tissues. These findings are consistent with a role of zinc as a cofactor in the Δ-6-desaturase enzyme reaction. The suggested role of zinc in essential fatty acid metabolism may be of significance in understanding how essential fatty acids protect against cardiovascular disease in general.
” [16]
A zinc deficient diet in rats over 5 weeks induced the hypolipidemia (low levels of blood lipids) without a significant effect on the fatty acid composition of tissue lipids, impaired the growth and relative weights of internal organs.
Daily injection of primrose oil (this oil contains the gamma-linolenic acid) reversed most of the effects of zinc deficiency on organ weights, growth and blood lipids.
Injecting the rats with safflower oil which contains comparable amounts of linoleic acid (18 : 2ω6) as primrose oil but is devoid of gamma linolenic-acid (18 : 3ω6) had only a partial effect on weights of the internal organs.
The other scientists in 1995 published the study “Activities of liver microsomal fatty acid desaturases in zinc-deficient rats force-fed diets with a coconut oil/safflower oil mixture of linseed oil” where they concluded that similarities of symptoms between zinc deficiency and (essential) fatty acids deficiency are not caused by disturbed desaturation of linoleic acid in zinc deficiency (which does not mean that zinc deficiency may not disturb the fatty acids metabolism in some other way).
”
Levels of fatty acids in liver phospholipids and microsomes derived by delta 4-, delta 5-, and delta 6-desaturation were not consistently changed by zinc deficiency in the rats fed both types of dietary fat [coconut oil and safflower oil mixture, lineseed oil]. Thus, the enzyme studies and also fatty acid composition data of liver phospholipids and microsomes indicate that zinc deficiency does not considerably disturb desaturation of linoleic and alpha-linolenic acid. Therefore, it is suggested that similarities between deficiencies of zinc and essential fatty acids described in literature are not due to disturbed desaturation of linoleic acid in zinc deficiency.
” [19]
This view might be supported by the other rat study (published in 1981) which concluded that zinc deficiency actually increases the desaturation of linoleic acid by delta 6-desaturase by 3.4 times. [18]
However, the same German authors of the study “Activities of liver microsomal fatty acid desaturases in zinc-deficient rats force-fed diets with a coconut oil/safflower oil mixture of linseed oil” mentioned above corrected or we may say specified their results in another study “Zinc deficiency and the desaturation of linoleic acid in rats force-fed fat-free diets” published in 1996.
The scientists presented that “in zinc-deficient rats there were changes of (n-6) PUFA levels typical for impaired delta 5 and delta 6 desaturation: linoleic acid and dihomo-gamma-linolenic acid were elevated; arachidonic acid, docosatetraenoic acid, and docosapentaenoic were lowered by zinc deficiency. Therefore, the study shows that zinc deficiency impairs desaturation of linoleic acid in rats force-fed fat-free diets and therefore supports results from former conventional zinc deficiency experiments suggesting a role of zinc for desaturation of linoleic acid.” [17]
There is a lot of information and contradictory results from many studies researching the effects of zinc on delta 5 and delta 6 desaturases.
But it seems to be all about the type and amount of fat the rats were fed before and during the experiments, if they were force-fed or if they eat voluntarily the amounts of food they wanted (which may be significantly negatively affected by zinc deficiency).
If I had to choose what results I believed more I would say that zinc definitely negatively impairs the proper fatty acids metabolism. I would’t dismiss the fact that omega 6 fatty acids deficiency and zinc deficiency exhibit the same symptoms and supplementation of any of those leads usually to significant clinical improvement.
What we can be sure about is that zinc deficiency significantly negatively impairs a lot of the physiological processes and leads to an inflammation.
Impaired activity of the fatty acids desaturases is just one of the ways how zinc deficiency may lead to an inflammation and the immune system problems.
Supplementation with gamma-linolenic acid
You should understand that minerals (and vitamins) like zinc just help some enzymes and processes in the body. But if due to any reason other than essential nutrient deficiency – like genetic mutation (variation) or infection – your health never improved then maybe there is a need for supplementation with non-essential nutrients like gamma-linolenic acid.
If there is something (genetic mutation, functional deficiency or infection) what prevents the conversion of linoleic acid to gamma-linolenic acid things can go very wrong without supplementing the gamma-linolenic acid in sufficient amounts.
Hopefully, I wrote my thoughts above clearly enough.
This does not mean that taking the gamma-linolenic acid (GLA) in form of Evening Primrose Oil or Borage Oil corrects the Zinc deficiency!
Zinc is involved in hundreds of enzymatic reactions and the one involving the – delta 6 desaturase – is just one of them.
Supplementation with Evening Primrose Oil or Borage Oil corrects the possible gamma-linolenic acid deficiency. And still there may be some suspicions if it is able to cross the blood-brain-barrier in sufficient amounts.
What Is The Best Form Of Zinc Supplement For Psoriasis
If you ever wondered what was the best form of zinc supplement for psoriasis in terms of absorption just read this post. The soils are depleted, wheat and other crops have little zinc content and phytic acid in bran binds the zinc in the digestive tract thus further lowering the bioavailable zinc which is so important in psoriasis.
There is a lot of forms of zinc in supplements – zinc oxide, zinc picolinate, zinc orotate, zinc bisglycinate chelate, zinc gluconate, zinc citrate, zinc L-carnosine, zinc monomethionine – but which one is the best?
In the past I recommended zinc picolinate and gluconate as the best zinc supplements for the price, but in this article you will see that there are even better ones.
Later, in 2017 I wrote a blog post describing the negative effects of zinc deficiency on omega 6 status. In other words a good part of symptoms of zinc deficiency may be caused by inadequate production of omega 6 fatty acids.
Zinc deficiency – growth retardation and hypogonadism
Zinc was found to be an essential nutrient humans can be deficient in in 1961 when a single case report of 21 year old male patient from Iran was published. The patient was diagnosed in 1958 with “dwarfism, hypogonadism, hepatosplenomegaly, rough and dry skin, mental lethargy, geophagia, and iron deficiency anaemia”.[21]
His diet was very low in animal protein and consisted mostly of unleavened bread. He also ate about 0.5 kg of clay every day. The intake of calories and protein (in form of cereals) was adequate and no other deficiency besides the iron deficiency was documented.
During the following 10 months more patients with the similar symptoms visited the hospital.
Growth retardation combined with testicular hypofunction was present in all of them and could not be explained by iron deficiency. No animal studies researching the effects of iron deficiency resulted in symptoms like that.
The only known nutrient causing growth retardation and hypogonadism in animal studies was zinc.
All patients improved on balanced diet which included the animal protein and iron supplementation.[21]
Is zinc supplement necessary in psoriasis?
You probably know that I am all for supplements and not buying all those opinions that food has all we need to thrive. Mostly when we are in troubles already and need some support to recover.
The very most people are mislead by thinking that if vegetable or fruit grow big and looks dark green (vegetable) or red, yellow, orange (fruit) it is healthy and has to have all the necessary nutrients.
It is not true and farmers and corporations know that.
In order to make vegetable and fruit grow big all they need is add the nitrogen, phosphorus and potassium.
These nutrients make the plants look healthy, grow tall and increase the yield.
However, the sad fact is that the nutritional value of plants is low as well as their vitality.
The apple you eat may look good and be 1 lb but its nutritional profile can be very poor.
Moreover, diet high in grains especially unrefined grains with bran decreases the bioavailable zinc in the digestive tract.
It is caused by phytic acid which is present in cereal bran and chelates the zinc, calcium, magnesium, iron and other minerals.
Soils are zinc depleted
Moreover, crop fields are very low in zinc so wheat (and other cereals) is often very low in zinc even before you ingest it. Phytic acid is just the nail in the coffin.
The study published in 1996 examined the 76 soil samples from major wheat growing area in Turkey – Central Anatolia.
”
In a soil and plant survey, and in field and greenhouse experiments the nutritional status of wheat plants was evaluated for Zn, Fe, Mn and Cu in Central Anatolia, a semi-arid region and the major wheat growing area of Turkey. All 76 soils sampled in Central Anatolia were highly alkaline with an average pH of 7. 9. More than 90% of soils contained less than 0.5 mg kg-1 DTPA-extractable Zn, which is widely considered to be the critical deficiency concentration of Zn for plants grown on calcareous soils. About 25% of soils contained less than 2.5 mg kg-1 DTPA-extractable Fe which is considered to be the critical deficiency concentration of Fe for plants. The concentrations of DTPA-extractable Mn and Cu were in the sufficiency range. Also the Zn concentrations in leaves were very low. More than 80% of the 136 leaf samples contained less than 10 mg Zn kg-1. By contrast, concentrations of Fe, Mn and Cu in leaves were in the sufficient range. In the field experiments at six locations, application of 23 kg Zn ha-1 increased grain yield in all locations. Relative increases in grain yield resulting from Zn application ranged between 5% to 554% with a mean of 43%. Significant increases in grain yield (more than 31%) as a result of Zn application were found for the locations where soils contained less than 0.15 mg kg-1 DTPA-extractable Zn. In pot experiments with two bread (Triticum aestivum, cvs. Gerek-79 and Kirac-66) and two durum wheats (Triticum durum, cvs. Kiziltan-91 and Kunduru-1149), an application of 10 mg Zn kg-1 soil enhanced shoot dry matter production by about 3.5-fold in soils containing 0.11 mg kg-1 and 0.15 mg kg-1 DTPA-extractable Zn. Results from both field observations and greenhouse experiments showed that durum wheats were more susceptible to Zn deficiency than the bread wheats. On Zn deficient soils, durum wheats as compared to bread wheats developed deficiency symptoms in shoots earlier and to a greater extent, and had lower Zn concentration in shoot tissue and lower Zn content per shoot than the bread wheats. The results presented in this paper demonstrate that (i) Zn deficiency is a critical nutritional problem in Central Anatolia substantially limiting wheat production, (ii) durum wheats possess higher sensitivity to Zn deficient conditions than bread wheats, and (iii) wheat plants grown in calcareous soils containing less than 0.2 mg kg-1 DTPA-extractable Zn significantly respond to soil Zn applications. The results also indicate that low levels of Zn in soils and plant materials (i.e. grains) could be a major contributing factor for widespread occurrence of Zn deficiency in children in Turkey, whose diets are dominated by cereal-based foods.
” [25]
What are the major outcomes of that study?
- Over 90% of soil samples contained less than 0.5 mg/kg of zinc which is VERY low and considered to be a critical deficiency for plants grown on calcareous soils (high levels of calcium carbonate).
- Over 25% of soil samples contained less than 2.5 mg/kg of iron which is considered to be a critical deficiency for plants.
- Manganese and Copper were is sufficient range in soil samples.
- The zinc concentrations in leaves were very low. Over 80% of 136 leaf samples contained less than 10 mg/kg of zinc.
- Iron, Manganese and Copper were found to be in the sufficient range in leaves.
- Application of 23 kg/ha of Zinc increased the yield from 5% up to 554% with a mean increase of 43%.
- Durum wheats were more susceptible to Zinc deficiency than bread wheats.
- Wheat grown on calcareous (containing high levels of calcium carbonate) soils with less than 0.2 mg/kg of zinc responded significantly to zinc application.

Here is the effect of foliar applied zinc on growth of barley plants in Central Anatolia
Image Source: I. Cakmak, A. Yilmaz, M. Kalayci, H. Ekiz, B. Torun, B. Erenoglu and H.J. Braun. Plant and Soil. Zinc deficiency as a critical problem in wheat production in Central Anatolia. Plant and Soil Vol. 180, No. 2 (March (II) 1996), pp. 165-172
Zinc application to soil increases the rice yield significantly as well.[26]

The efects of zinc appication to soil on rice yield.[6, 7]
Image Composed By: Nazanin Roohani, Richard Hurrell, Roya Kelishadi, Rainer Schulin. Zinc and its importance for human health: An integrative review. J Res Med Sci. 2013 Feb; 18(2): 144–157.
Best form of zinc for psoriasis
In order to give you a clear answer on what zinc form and which supplement I consider the best, I will tell you that right now before I mention any studies.
The best form of zinc which is easily available and sells for a low price is zinc bisglycinate which is a zinc ion (ZN2+) bound to two molecules of amino acid glycine.
Nature’s Way Zinc which uses zinc bisglycinate works great and is the cheapest supplement of all others I am going to mention below.
If you want to take the zinc where manufacturer declares Albion Laboratories as the source of raw material then you can use NOW Foods Zinc or Solgar Chelated Zinc. Solgar does not state if the zinc compound in their product is TRAACS (The Real Amino Acid Chelate System) but it likely is as Albion lists no other zinc compounds on its website (as of November 2017).
- Nature’s Way Zinc (Zinc Bisglycinate)
- NOW Foods Zinc (Zinc Bisglycinate – TRAACS by Albion)
- Solgar Chelated Zinc (Zinc Bisglycinate by Albion)
- Carlson Labs Zinc (Zinc glycinate)
If you took more than 60 mg of zinc daily you might wanted to add a copper supplement in order to balance the effects of zinc on copper function and possible zinc toxicity.
- Twinlab Copper (copper gluconate)
The science says Zinc bisglycinate is superior
The most older studies ranked the assimilation of zinc picolinate as the best. That’s why zinc picolinate is generally considered as better compared to other forms like zinc gluconate or zinc citrate.
In study from 1987 the absorption after oral administration of zinc picolinate, zinc citrate and zinc gluconate was tested.
The significant difference in hair, urine and red blood cell levels was found after supplementation of zinc picolinate only (zinc levels went up).
”
The comparative absorption of zinc after oral administration of three different complexed forms was studied in 15 healthy human volunteers in a double-blind four-period crossover trial. The individuals were randomly divided into four groups. Each group rotated for four week periods through a random sequence of oral supplementation including: zinc picolinate, zinc citrate, and zinc gluconate (equivalent to 50 mg elemental zinc per day) and placebo. Zinc was measured in hair, urine, erythrocyte and serum before and after each period. At the end of four weeks hair, urine and erythrocyte zinc levels rose significantly (p less than 0.005, p less than 0.001, and p less than 0.001) during zinc picolinate administration. There was no significant change in any of these parameters from zinc gluconate, zinc citrate or placebo administration. There was a small, insignificant rise in serum zinc during zinc picolinate, zinc citrate and placebo supplementation.
“[23]
The recent studies show that zinc amino acid chelates but also amino acid chelates of other minerals are absorbed better.
A study published in International Journal for Vitamin and Nutrition Research in 2007 stated that Zinc bisglycinate bioavailability after oral administration was 43.4% higher compared to Zinc gluconate.
”
The aim of the present study was to compare the oral bioavailability of zinc bis-glycinate (a new formulation) with zinc gluconate (reference formulation). A randomized, cross-over study was conducted in 12 female volunteers. The two products were administrated orally at the single dose of 15 mg (7.5 mg x 2), with a 7-day wash-out period between the two tests.
…
Bis-glycinate administration was safe and well tolerated and bis-glycinate significantly increased the oral bioavailability of zinc (+43.4%) compared with the gluconate.
“[24]
Another study from 2008 compared the bioavailability of 4 popular zinc complexes – oxide, picolinate, gluconate and glycinate.
”
In the present study, in 12 young adult women, four zinc complexes (oxide, picolinate, gluconate, and glycinate) were compared for acute uptake using a zinc tolerance test (plasma zinc changes hourly for 4 h after a single zinc dosing), and two related measures (erythrocyte zinc and activity of the zinc enzyme 5′-nucleotidase over the same 4 h period). Plasma zinc rankings based on area under the curve, as well as by rank results per person, were: glycinate > gluconate > picolinate=oxide. Erythrocyte zinc rankings based on area under the curve, as well as by rank results per person, were: glycinate > picolinate >oxide > gluconate. None of the supplement significantly increased 5′-nucleotidase activities at any of the time points. In summary, zinc glycinate showed the best acute uptake of the four complexes tested.Disclosure Note: R DiSilvestro has a consultant retainer agreement with Albion Laboratories, who supplied zinc glycinate, but this was not true when the study was done, nor did Albion fund this study.
“[22]
As you can see zinc glycinate ranked the best.
Conclusion
Personally, I have tried zinc picolinate, gluconate and glycinate; and zinc glycinate works by far the best in my opinion. But take that just as it is – my opinion because the outcomes and effects I experienced might be significantly improved by other supplements I took concurrently – especially B6 (and other b-vitamins).
The combination of B6 and zinc is a well known formula for pyroluria (-like pathologic states) which is a subset of porphyria disorder.
Zinc should be taken with food as it may cause nausea when taken on an empty stomach.
One interesting article about the minerals, zinc and its effects on plants is published on MaximumYield.com. I recommend you to read it.
References:
1) Swaminath G, Steenhuis J, Kobilka B, Lee TW. Allosteric modulation of beta2-adrenergic receptor by Zn(2+). Mol Pharmacol. 2002 Jan;61(1):65-72.
2) von Bülow V, Rink L, Haase H. Zinc-mediated inhibition of cyclic nucleotide phosphodiesterase activity and expression suppresses TNF-alpha and IL-1 beta production in monocytes by elevation of guanosine 3′,5′-cyclic monophosphate. J Immunol. 2005 Oct 1;175(7):4697-705.
3) Ananda S. Prasad. Clinical, immunological, anti-inflammatory and antioxidant roles of zinc. Experimental Gerontology Volume 43, Issue 5, May 2008, Pages 370–377 Zinc and Ageing (ZINCAGE Project)
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