Chronic heart failure is a potentially life-threatening condition that affects millions of people worldwide. A group of scientists recently looked at the relation between chronic heart failure and zinc deficiency and how zinc supplementation can improve heart health by various accounts. The scientists also investigated why zinc deficiencies are so common. Their study is published in the Journal of Cardiac Failure.
Chronic heart failure normally develops slowly. The symptoms occur when the heart is no longer able to pump sufficient amounts of blood trough the body. According to the statistics, around 33 percent of heart failure patients die within a year of being hospitalized with heart failure for the first time. It is therefore vital to take the right preventive steps for good heart health.
There is a link between chronic heart failure and oxidative stress in the body. Oxidative stress is an imbalance between free radicals and protective antioxidants such as zinc. Free radicals are a natural byproduct of cellular energy metabolism and the free radial load is increased by ageing, stress, inflammation, poisoning, smoking, and radiation. Free radicals are highly aggressive molecules that are able to start a chain reaction, in which they attack the lipids in cell membranes and the DNA and proteins inside the cells. Free radicals also attack the essential cholesterol that circulates in the blood. Cholesterol, however, does not become dangerous unless it is oxidized by free radicals. When this happens, the oxidized cholesterol is embedded in the vessel wall where it may eventually lead to atherosclerosis.
Supplementation with zinc and other antioxidants improves heart health
Not only is zinc a powerful antioxidant, it is a trace element that is needed for around 1,000 enzyme processes that are crucial for energy turnover, heart function, and the cardiovascular system. Zinc is also able to regulate the renin-angiotensin-aldosterone system that controls blood pressure and the fluid balance. The scientists behind the new study analyzed a number of earlier studies of zinc deficiency and heart failure in order to get a better understanding of the problem. They concluded that chronic heart failure may be a result of getting too little dietary zinc or having poor nutrient absorption. It is therefore technically possible to be deficient of zinc, even if there is enough zinc in the diet you eat. Certain types of medication may also increase urinary zinc excretion. In addition, the scientists point to the fact that chronic inflammation, which is quite common in cardiovascular disease, increases the need for zinc because of its antioxidant properties.
The scientists conclude that lack of zinc sets the stage for cardiovascular diseases and chronic heart failure by means of oxidative stress and physiological mechanisms that fail to function optimally when there is too little zinc in the body.
Several randomized, double-blinded studies have shown that zinc supplementation given to heart patients improves several parameters of cardiac function compared with placebo. In one study, the scientists gave a combination of zinc and selenium, which is another important antioxidant, and this combination had a synergistic effect. In another study, zinc was given together with B vitamins and vitamin D.
The heart is highly sensitive towards oxidative stress
A team of scientists from the Technical University in Munich (TUM) studied heart muscles in pigs to see how the heart’s high energy turnover automatically resulted in an increased production of free radicals. They also observed that the pig hearts had a lower antioxidant capacity compared with other tissues. The heart is therefore especially sensitive towards oxidative stress.
The scientists looked closer at this by measuring the zinc status in the pigs and comparing it to the heart muscle’s content of the two antioxidants, glutathione and vitamin E (α-tocopherol), which are particularly important for the protection of the cell membrane.
The scientists found that levels of glutathione and vitamin E in heart muscle tissue together went down along with the decreasing zinc status. Also, they found that zinc supplementation increased the heart’s ability to withstand oxidative stress in a very early phase.
Zinc supplements may therefore be of vital importance to humans, as oxidative stress predisposes to heart disease. Their study is published in Journal of Nutrition.
The team of scientists also refer to other studies showing that reduced zinc levels in the body are related to subclinical inflammation. This increases the risk of oxidative stress, which can damage the cardiovascular system and the heart.
An estimated 25% of the world’s population is zinc-deficient
Zinc deficiency is widespread for many reasons
Zinc deficiencies are mainly a result of poor eating habits and lack of animal protein, which is normally a good source of zinc. High intake of iron and calcium and overconsumption of alcohol are also contributing factors. Ageing, diarrhea, poorly managed diabetes and other ailments may also cause zinc deficiency. The same is the case with several types of medicine such as diuretics, ACE-inhibitors, antacids, corticosteroids, antibiotics, and birth control pills.
Sources and supplements
Zinc is mainly found in oysters, liver, meat, shellfish, dairy products, nuts, seeds, kernels, and beans. Zinc from animal sources have the best absorption in the body. The reference intake (RI) level for zinc in adults is 10 mg. If you are lacking zinc, you should primarily try to include more zinc sources in your diet. When using supplements, be aware that many products contain inorganic sources like zinc sulfate and zinc oxide that the body has difficulty with absorbing. Zinc gluconate and zinc acetate are organic forms that are much easier for the body to absorb and utilize.
A blood sample can show if you are zinc-deficient. If your doctor has detected a deficiency, high-dosed supplements can solve the problem.
According to the European Food Safety Authority (EFSA), the safe upper intake level for adults (including pregnant women) is 25 mg daily. Short-term consumption of high zinc doses from e.g. oysters or supplements are harmless.
Rosenblum H et al. Zinc deficiency and Heart Failure: A Systematic Review of the Current literature. Journal of Cardiac Failure, 2020 Jan.
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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