We have so much in New Zealand, surrounded by some of the most stunningly natural beauty in the world. The land that gives us so much inspiration and joy, may also be part of the problem in causing New Zealanders to have one of the highest rates of mood disorders, such as depression in the world (*1).
Low Zinc in the Soil
The problem lies in part in the land itself. The soil in New Zealand is low in many important nutrients, such as zinc, magnesium, selenium, boron and iodine. The food choices we make can compound that problem. If you eat little food which naturally contains these minerals; and that food has been grown in soil which is depleted, you are likely to have health problems triggered by deficiencies of these minerals.
Diet can Deplete Zinc and Trigger Depression and other problems
You may make things worse by having a diet which depletes your body further of the minerals. Here I'll tell you a little about how low zinc levels in your body can increase your risk of suffering from depression.
Zinc is an essential mineral, when your body does not have enough, you are more likely to suffer not only from mental health problems [1], particularly depression [2-4], but you are also at increased risk of lowered immunity, and chronic diseases, such as cancer and type 2 diabetes [5]. A study this year of 402 students found those who had the most zinc in their diet were least likely to have depression [6].
The knowledge that low zinc is likely in depression is not new; over 20 years ago zinc levels in the body were found to be lower in people with depression [7].
Supplementing with Zinc and/or Pharmaceutical Antidepressants
Supplementation of zinc has an antidepressant effect [1, 8-10]; and it seems to help whether people find pharmaceutical antidepressants helpful or not [2, 11, 12]. Studies have shown zinc has an effect on the chemicals in the brain which are involved in depression [9, 13]. It is not necessarily a case of choosing between pharmaceutical antidepressants or zinc. Zinc has been shown to improve the effect of some antidepressants [1] (imipramine and citalopram) [8].
Zinc in the Nervous System and Brain
It is fairly logical that zinc is important to mental health since in the body zinc is found (mainly) in the brain; so is very important for the health of the nervous system) [8]. When zinc is low in the diet, a number of nervous system problems may result including problems with memory, a symptom often experienced with depression [9, 11]. With this in mind it is not surprising that zinc deficiency is common is the elderly [13].
Depression and Inflammation
Some new ideas on the causes of depression suggest inflammation in the body could result in less new nerve cells being formed, and more nerve cells wearing down. In patients with major depression, low zinc levels appear to be related to increased inflammation [11, 12].
In a large study in 2012 it was found inadequate zinc in the diet of women contributed to depressive symptoms and for those taking pharmaceutical antidepressants supplements of zinc helped relieve their symptoms [14].
Many factors contribute to depression
Certainly many factors contribute to depression; increased stress can trigger depression, however, adequate zinc intake appears to buffer the impact of stress [15], and decrease likelihood of depression.
Other nutrients may be low in depression
Other important nutrients which may be low in depression include magnesium, B vitamins and the quality fats such as omega 3 [3, 6].
FOOD STATE ZINC and absorption
It is very important that if you take a zinc supplement you do not have a dose too high for your body. Too much zinc, more than 40 mg a day can be toxic to the body [16]. Iron in some supplement forms reduces the availability of zinc, however iron in food [17] or in the Food State supplement form will not affect the absorption of zinc.
Always be careful if supplementing your diet with zinc as too much zinc can have detrimental effects on immunity and other aspects of your health. Food State supplements are all of a safe low dose since studies show they are absorbed more easily into the body than other supplement forms; in addition since they are in the same form as food, there is no problem taking Food State iron supplements at the same time (*16,*17).
Foods containing zinc
Foods that contain zinc include meat (organic is best), poultry (organic is best), seafood especially. oysters, grains, pumpkin seeds, sunflowers seeds mushrooms, organic soybeans, and brewers yeast [18, 19]. Animal protein helps with zinc absorption, so vegetarians need to be especially careful to get adequate zinc[4, 20].
Substances which Lower Zinc
Phytic acid found in grains prevents zinc absorption [19], but if you soak the grains overnight you will break down the phytic acid, so zinc can be absorbed [17].
Cadmium a toxic element also depletes zinc [17]. The most common source of toxic levels of cadmium is cigarette smoke (stop smoking now!) [21]. If you find you cannot stop smoking immediately, supplements of zinc may help to decrease the immune damage caused by cadmium [22]. But there are many more damaging aspects of smoking so work towards quitting as soon as possible.
Alcohol depletes zinc as zinc forms part of the enzyme which breaks down alcohol, so every time you have an alcoholic drink you will be using up your precious zinc reserves [23, 24].
Contact Bay Health Clinic today to find out more or to book a consultation with one of our Naturopaths; if needed they will also prepare tailored herbal medicines and recommend supplements to help you feel your best. Call 07 571 3226 or email us: ask@bayhealth.nz
References
*1. http://www.mentalhealth.org.nz/page/128-mental-health-quick-statistics
1. DiGirolamo AM, Ramirez-Zea M: Role of zinc in maternal and child mental health. The American Journal of Clinical Nutrition 2009, 89(3):940S-945S. http://ajcn.nutrition.org/content/89/3/940S.abstract
2. Lai J, Moxey A, Nowak G, Vashum K, Bailey K, McEvoy M: The efficacy of zinc supplementation in depression: Systematic review of randomised controlled trials. Journal of affective disorders 2012, 136(12):e31-e39.http://www.sciencedirect.com/science/article/pii/S0165032711003533
3. Jacka FN, Maes M, Pasco JA, Williams LJ, Berk M: Nutrient intakes and the common mental disorders in women. Journal of affective disorders 2012, 141(1):79-85.http://www.sciencedirect.com/science/article/pii/S0165032712001140
4. Amani R, Saeidi S, Nazari Z, Nematpour S: Correlation Between Dietary Zinc Intakes and Its Serum Levels with Depression Scales in Young Female Students. Biological Trace Element Research 2010, 137(2):150-158. http://dx.doi.org/10.1007/s12011-009-8572-x
5. Chasapis C, Loutsidou A, Spiliopoulou C, Stefanidou M: Zinc and human health: an update. Archives of Toxicology 2012, 86(4):521-534. http://dx.doi.org/10.1007/s00204-011-0775-1
6. Yary T, Aazami S: Dietary Intake of Zinc was Inversely Associated with Depression. Biological Trace Element Research 2012, 145(3):286-290. http://dx.doi.org/10.1007/s12011-011-9202-y
7. McLoughlin IJ, Hodge JS: Zinc in depressive disorder. Acta Psychiatrica Scandinavica 1990, 82(6):451-453.http://dx.doi.org/10.1111/j.1600-0447.1990.tb03077.x
8. Szewczyk B, Poleszak E, Sowa-Kucma M, Siwek M, Dudek D, Ryszewska-Pokrasniewicz B, Radziwon-Zaleska M, Opoka W, Czekaj J, Pilc A et al: Antidepressant activity of zinc and magnesium in view of the current hypotheses of antidepressant action. Pharmacol Rep 2008, 60(5):588-589. http://www.ncbi.nlm.nih.gov/pubmed/19066406
9. Takeda A, Tamano H, Ogawa T, Takada S, Ando M, Oku N, Watanabe M: Significance of serum glucocorticoid and chelatable zinc in depression and cognition in zinc deficiency. Behavioural Brain Research 2012, 226(1):259-264.http://www.sciencedirect.com/science/article/pii/S0166432811006966
10. Sowa-Kuma M, Legutko B, Szewczyk B, Novak K, Znojek P, Poleszak E, Papp M, Pilc A, Nowak G: Antidepressant-like activity of zinc: further behavioral and molecular evidence. Journal of Neural Transmission 2008, 115(12):1621-1628. http://dx.doi.org/10.1007/s00702-008-0115-7
11. Szewczyk B, Kubera M, Nowak G: The role of zinc in neurodegenerative inflammatory pathways in depression. Progress in Neuro-Psychopharmacology and Biological Psychiatry 2011, 35(3):693-701.http://www.sciencedirect.com/science/article/pii/S0278584610000576
12. Maes M, Vandoolaeghe E, Neels H, Demedts P, Wauters A, Meltzer HY, Altamura C, Desnyder R: Lower serum zinc in major depression is a sensitive marker of treatment resistance and of the immune/inflammatory response in that illness. Biological psychiatry 1997, 42(5):349-358.http://www.sciencedirect.com/science/article/pii/S0006322396003654
13. Takeda A: Zinc Signaling in the Hippocampus and Its Relation to Pathogenesis of Depression. Molecular Neurobiology 2011, 44(2):166-174. http://dx.doi.org/10.1007/s12035-010-8158-9
14. Maserejian NN, Hall SA, McKinlay JB: Low dietary or supplemental zinc is associated with depression symptoms among women, but not men, in a population-based epidemiological survey. Journal of affective disorders 2012, 136(3):781-788.http://www.sciencedirect.com/science/article/pii/S0165032711005659
15. Roy A, Evers SE, Avison WR, Campbell MK: Higher zinc intake buffers the impact of stress on depressive symptoms in pregnancy. Nutrition Research 2010, 30(10):695-704.http://www.sciencedirect.com/science/article/pii/S0271531710001867
16. Nriagu J: Zinc Toxicity in Humans. In: Encyclopedia of Environmental Health. Edited by Editor-in-Chief: Jerome ON. Burlington: Elsevier; 2011: 801-807.http://www.sciencedirect.com/science/article/pii/B9780444522726006759
*16 Tompkins TA, Renard NE, Kiuchi A:Clinical Evaluation of the Bioavailability of Zinc-enriched Yeast and Zinc Gluconate in Healthy Volunteers . Biological Trace Element Research 2007, 120(1-3).
* 17 Vinson J, Tompkins T, Agbor G: Comparative Bioavailability of Mineral-enriched Gluconates and Yeast in Rat Liver After DepletionRepletion Feeding. Biological Trace Element Research 2007, 118(2):104-110.
17. Lonnerdal B: Dietary Factors Influencing Zinc Absorption. J Nutr 2000, 130(5):1378S-1383.http://jn.nutrition.org/cgi/content/abstract/130/5/1378S
18. NIH-USA: Selected Food Sources of Zinc. In: Health Professional Fact Sheet: Zinc. National Institutes of Health, NIH; 2009.http://ods.od.nih.gov/factsheets/zinc.asp#h3
19. MoH-NZ: Food and Nutrition Guidelines for Healthy Adults. In: Other Nutrients Zinc Edited by Ministry of Health N; 2003.http://www.moh.govt.nz/moh.nsf/238fd5fb4fd051844c256669006aed57/7b14edc233cad7c5cc256d80000b1a6d?OpenDocument
20. Australian Gov TNhamrc, Min of Health N: Nutrient Reference Values for Australia and New Zealand Including Recommended Dietary Intakes. In. Edited by Min of Health N: The National health and medical research council, Australia; 2005.http://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/n35.pdf
21. Bachelet M, Pinot F, Polla RI, Francois D, Richard MJ, Vayssier-Taussat M, Polla BS: Toxicity of cadmium in tobacco smoke: protection by antioxidants and chelating resins. Free Radic Res 2002, 36(1):99-106.http://www.ncbi.nlm.nih.gov/pubmed/11999708
22. Chowdhury BA, Friel JK, Chandra RK: Cadmium-Induced Immunopathology Is Prevented by Zinc Administration in Mice. J Nutr 1987, 117(10):1788-1794. http://jn.nutrition.org/cgi/content/abstract/117/10/1788
23. Vallee BL, Hoch FL: Zinc, a Component of Yeast Alcohol Dehydrogenase. Proc Natl Acad Sci U S A 1955, 41(6):327-338. http://www.ncbi.nlm.nih.gov/pubmed/16589675
24. Nasolodin VV, Rusin V, Vorob'ev VA: [Effect of alcohol on iron, aluminum and zinc balance]. Vopr Pitan 1987(1):23-26. http://www.ncbi.nlm.nih.gov/pubmed/3564382
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