Can a selenium deficiency cause hypertension?
Yes, according to a new study published in Free Radical Biology & Medicine, lack of selenium lowers the kidneys’ sodium excretion via different mechanisms, and that leads to elevated blood pressure. The study results are highly relevant because hypertension and subsequent premature death is a growing global problem. Selenium deficiency is also a widespread problem. One billion people worldwide are believed to be lack this essential nutrient, primarily because of the selenium-depleted agricultural soil in large parts of China, Europe, and other places.
Epidemiological studies have shown a link between low selenium status in the body and an increased risk of hypertension but so far, science has not known the exact mechanism. In the new study, a team of researchers has fond that rats who were fed a selenium-depleted diet for 16 weeks developed hypertension at the same time as excreting less sodium.
It is commonly known that sodium binds fluid. If sodium accumulates in the body, hypertension may occur. It is also known that potassium controls the kidneys’ sodium excretion, and the balance between sodium and potassium is crucial. As it turns out, selenium also affects how much sodium the kidneys excrete.
The scientists found that hypertension in the selenium-deficient rats was related to an increased expression of the angiotensin 2 type 1 receptor in the kidneys and that the effect on blood pressure is a result of angiotensin 2’s blood vessel-constricting effect.
Also, the researchers observed that selenium deficiency increases the formation of a type of free radicals called hydrogen peroxide (H202). Hydrogen peroxide is a natural byproduct of cellular energy turnover, and the energy turnover in the kidneys is quite massive. It is also important for the protective antioxidants to neutralize these free radicals in order to prevent oxidative stress from occurring, as this can damage healthy cells and tissues. Selenium is relevant here because it fuels the powerful GPX1 antioxidants that normally neutralize hydrogen peroxide and other free radicals.
Moreover, the scientists discovered that lack of GPX1 increases the activity of NF-κB (nuclear factor kappa B), which is a protein complex found in most cells. NF-κB is involved in the cellular response to stress, free radicals, and infections. According to the new study, selenium affects the kidney function and their sodium excretion.
- Kidneys contain relatively large quantities of selenium
- This is because selenium is important for the energy turnover and other metabolic processes.
- Selenium also supports the powerful GPX antioxidants that protect cells and tissues against oxidative stress
Elevated blood pressure is a ticking bomb
One of the major risk factors of blood clots, heart failure, stroke, and other cardiovascular diseases is elevated blood pressure, so, health-wise, this problem is a ticking bomb. The number of patients with elevated blood pressure has doubled in the period from 1990-2019 and is now one of the leading causes of death. Many people have hypertension without being aware of the problem, which makes is even more dangerous.
The development of hypertension is rather complicated as it involves genes, diet, environmental factors, and diseases like metabolic syndrome and diabetes. It is commonly known that excessive intake of salt and refined carbohydrates is linked to elevated blood pressure. The same is the case with too little potassium, a mineral that we mainly get from vegetables and fruit. In recent years, science has also become more aware of the importance of different trace elements such as selenium.
Selenium deficiency is a global problem
We get selenium from organ meat, fish, eggs, corn, and different crops. The selenium content in the agricultural soil is low in large parts of Europe, China, and various other places in the world. As a result, an estimated 500 million to one billion people worldwide lack selenium. This has enormous consequences for public health.
Selenium supports well over 25 different selenium-dependent proteins (selenoproteins) that are important for a host of metabolic processes and also serve as powerful antioxidants. It is already known that too little selenium is linked to cardiovascular diseases like atherosclerosis, ischemic heart disease, and heart failure. Now, according to the new study, selenium deficiency can also trigger hypertension.
Lifu Lei et al. Selenium deficiency causes hypertension by increasing renal AT1 receptor expression via GPx1/H2O2/NF-κB pathway. Free Radical Biology and Medicine 2 March 2023
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