Zinc is an essential mineral for the functioning of our organism.
In the human body, zinc is located mainly in the liver, pancreas, kidneys, bones and muscles, but also in the eyes, skin, hair and nails. In men, zinc is also found in high amounts in the prostate and sperm.
What are their functions and their importance?
Zinc has numerous functions, being involved in the functioning of about 300 enzymatic reactions in our body. This means that zinc works as a kind of ignition key for almost 300 “machines” in our organism – if there is no zinc, some of these “machines” do not work or work less well, and depending on the “machine” and the cell in cause, the consequences are diverse. Regulation of gene expression, functioning of the immune system, wound healing and proper sperm function are just some of its functions.
Like all other nutrients, we can have too low levels (nutritional deficiencies), relatively low levels (suboptimal levels), adequate levels and toxic levels.
When zinc levels are too low, hair loss, growth retardation, hypogonadism, skin and eye injuries, immune deficiencies that can lead to recurrent infections, difficulty in healing, change in taste and even more serious deficiencies can be observed. it can even be fatal. Fortunately, these situations are rare these days in developed countries, but have been observed in individuals undergoing gastric bypass surgery for obesity, and who have not had adequate post-operative nutritional follow-up.
When zinc levels are low, as in cases of moderate deficiencies or suboptimal levels, it is possible to observe some of these symptoms, but in a milder form. There may be some hair loss or weaker hair, acne, behavioral disorders, some immune breakdown facilitating flu and recurrent infections, more difficult healing and some change in taste. In men, it can be reflected in a lower production of sperm and may even condition fertility. Unlike serious zinc deficiencies, these are extraordinarily common.
Look at your nails: if they have white horizontal stripes, it could very well be a sign of zinc deficiency.
The presence of stretch marks can also be a sign of lower zinc levels.
Who is at risk of having a zinc deficiency?
A lower zinc intake can occur when there is a diet rich in overly processed foods, especially when it coincides with a diet poor in quality protein sources.
Given the richness of sperm in zinc, and given the importance of zinc in the synthesis of more sperm, a sexually active man is at risk of zinc deficiency. This situation becomes more worrying in the case of couples who are trying to conceive, because the more they try, the more zinc the man loses, which reduces his fertility. In this case, consider nutritional supplementation or increase your intake of oysters – the food whose zinc content clearly stands out from all other foods.
A very common problem is the consumption of food cooked in copper utensils or in water that passes through copper pipes. Copper competes with zinc for absorption, so a diet that is too rich in copper leads to zinc deficiency. It is important to note that excess calcium and iron can also compete with zinc absorption.
Zinc absorption takes place mainly in the initial part of the small intestine, so surgical interventions that prevent food from passing through this (such as gastric bypass surgery) can seriously compromise zinc absorption. The presence of intestinal pathologies that can lead to nutritional malabsorption, such as Crohn’s disease, can also induce zinc malabsorption, and consequently, a deficiency of this nutrient.
What foods are richest in Zinc?
Oysters are undoubtedly the food that clearly stands out in this category, containing around 15mg per oyster. Seafood, meat, eggs, whole grains, legumes such as beans and peas and ginger are also interesting sources of zinc.
How to measure zinc levels?
Although most zinc is contained within cells or bound to proteins, plasma zinc levels can be used for a first assessment. It is not a completely reliable marker when used alone, as it is not able to detect mild or moderate deficiencies, but it appears low in the face of a nutritional zinc deficiency. This is a relatively common blood test in most labs.
For a more in-depth study to determine suboptimal zinc deficiencies, but which do not meet the requirements of nutritional deficiency, it will be necessary to complement this blood analysis with other analytical parameters, namely the erythrocyte zinc dosage, a hair mineralogram, an adequate history clinic and a detailed nutritional assessment.
Supplementary – how and how much?
Recommended daily doses of zinc are up to 10 – 12 mg/day, and maximum doses for the general population are around 40 mg/day. Therefore, a supplementation between 5 – 15 mg/day is safe, and can go up to 40 mg/day for short periods of time and when there are signs of deficiency. We advise against the supplementation of doses higher than these, without analytical control and without the supervision of a health professional, however, this may eventually advise the use of higher doses.
Excessively high doses of zinc can lead to a copper deficiency and a depression of the immune system. Toxic effects may include dizziness, vomiting, lethargy and anemia.
The forms of zinc best absorbed through supplements are in the form of picolinate or amino acid chelates. Supplements in the form of ascorbate, citrate and gluconate also have acceptable absorption, with the sulfate form having the lowest absorption.
If you are thinking of getting pregnant or if you experience any of the symptoms described above, you may want to consider measuring your zinc levels, and possibly the need for supplementation in this mineral.