- and provide other benefits
Zinc is a trace element that is necessary for around 300 enzymes that control the thyroid gland, fertility, the nervous system, the immune system, and a number of other functions. A team of scientists from the Technical University of Munich (TUM) has found a close link between the body’s zinc status and cardiac function. Although clinical zinc deficiencies are rare, short-term subclinical zinc deficiencies are more widespread than previously thought. Even a minor zinc deficiency may affect cardiac health and the countless enzyme processes that depend on the presence of zinc. Besides, zinc is a powerful antioxidant that protects cells against oxidative stress. There are many reasons why it is important to get enough of this nutrient.
When the balance between harmful free radicals and protective antioxidants is disturbed, the body is exposed to oxidative stress. Free radicals are a metabolic byproduct of cellular energy turnover, and the amount of free radicals increases additionally in connection with ageing processes, stress, inflammation, poisoning, smoking, and radiation. Free radicals are aggressive molecules that damage cells and their membranes, causing disease and deterioration. Our only protection against these harmful compounds is the presence of vitamin A, vitamin C, and vitamin E plus zinc, selenium, Q10, and different plant compounds.
Earlier studies show that severe zinc deficiency may lead to serious clinical symptoms and increased cellular oxidative stress. These severe zinc deficiencies are very rare though. However, short-term subclinical zinc deficiencies are widespread and typically occur among vegans, vegetarians, older people and other exposed groups. When it comes to zinc and its influence on oxidative stress and cardiac health, the scientific literature is limited.
|Vegans, vegetarians, and older people are more prone to zinc deficiency. Birth control pills, various types of medicine, and different diseases may also increase the risk of becoming zinc-deficient.|
The heart is more sensitive towards oxidative stress
The team of TUM researchers studied the cardiac muscle because of its active metabolism that enables the heart to contract approximately 100,000 times daily to pump blood to all parts of the body. The elevated energy turnover automatically leads to an increased production of free radicals. Moreover, the heart has lower antioxidant capacity than other tissues in the body, which is why it is highly sensitive towards oxidative stress.
The researchers investigated the problem by measuring the body’s zinc status and comparing it with the heart muscle’s content of two other antioxidants, glutathione and vitamin E (alpha-tocopherol), both of which are responsible for protecting the cell membranes.
Oxidative stress is controlled by the body’s zinc status
Because zinc is a trace element of which we only need minimal amounts from our diet, the scientists were able to provoke zinc deficiency of various degrees in piglets in a matter of days. Afterwards, they studied how the heart muscles of the animals responded to different levels of zinc deficiency. The researchers noted that the concentration of glutatathione and vitamin E in the heart muscle decreased in step with the decreasing zinc levels. They also observed that zinc supplementation helped the heart withstand oxidative stress at a much earlier stage. Therefore, zinc supplements may be of vital importance, as oxidative stress predisposes to heart disease according to several published studies.
A zinc deficiency makes cells vulnerable and increases the risk of inflammation
What the German researchers also discovered was that those genes that cause diseased and worn out cells to self-destruct (a process known as programmed cell death or apoptosis) were dialed up with decreasing zinc levels. In other words, cells became increasingly vulnerable and perished much faster. According to Daniel Brugger, who headed the study, the piglets’ bodies were no longer able to compensate for the low intake of selenium, although the study only lasted a few days.
After the initial phase of zinc deficiency, the researchers observed that the heart muscle increased its zinc levels. This increase of zinc in the heart muscle tissue sequestered zinc from other organs, especially the kidneys, liver, and pancreas. The researchers even refer to other studies pointing to a link between decreasing zinc levels and subclinical inflammation. This also affects the cardiovascular system, the immune system, and other organs.
Zinc deficiencies are a result of many things
Lack of zinc is mainly caused by poor dietary habits and lack of animal protein, which is normally a good source of zinc. Deficiencies are also seen as a result of ingesting too much iron and calcium and drinking too much alcohol. Excessive sweating, ageing processes, celiac disease, diarrhea, poorly managed diabetes and other conditions may also lead to zinc deficiency. The same is the case with several kinds of medicine such as diuretics, ACE inhibitors, antacids, corticosteroids, antibiotics, and birth control pills.
|An estimated 25% of the world’s population has zinc deficiency, which can be divided into minor, average, and severe deficiency.|
Sources and supplements
Zinc is found in foods such as oysters, liver, meat, shellfish, dairy products, nuts, seeds, kernels, and beans. Zinc from animal sources is easier for the body to absorb. If a zinc deficiency is suspected, make sure to include several good zinc sources in the diet and consider taking a supplement. A zinc deficiency can be detected from a blood sample. In the case that the doctor has observed a deficiency, high-dosed zinc supplementation can be useful.
Daniel Brugger and Wilhelm M. Windisch: Short-Term Subclinical Zink Deficiency in Weaned Piglets Affects Cardiac Redox Metabolism and Zinc Concentration. Journal of Nutrition 2017
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