Selenium is a nutrient that performs an important position in human well being, contributing to the thyroid and immune operate, DNA restore, and cardiovascular and cognitive well being.
It acts as an antioxidant – substances that shield cells from unstable molecules that may injury DNA, proteins and cell membranes. It might probably even shield in opposition to most cancers.
Selenium is a crucial hint component present in residing organisms, soil and vegetation, and your physique wants solely a small quantity of it to operate. The advisable dietary allowance for selenium in adults is 55 micrograms per day, with an higher restrict of 400 micrograms. Compared, adults want between 900 to 10,000 micrograms each day of copper, one other hint component, and between 8,000 to 40,000 micrograms of the hint component zinc.
An extra or deficiency of selenium can have vital well being penalties. In my work as a pharmaceutical science researcher, my colleagues and I examine the potential use of selenium to spice up the effectiveness of chemotherapy for most cancers therapy.
A dose of selenium
Selenium was first found in 1817 by chemist Jöns Jacob Berzelius whereas analyzing an impurity in a batch of sulfuric acid produced in a manufacturing facility in Sweden. Berzelius initially thought the fabric was the component tellurium, however he ultimately realized that it was really an unknown substance on the time. He named the mineral after Selene, the Greek goddess of the Moon, due to its similarity to tellurium, which had been named after the Roman goddess of the Earth.
Selenium exists in each natural and inorganic kinds. Natural compounds include carbon atoms and are sometimes derived from residing organisms, whereas inorganic compounds do not need carbon atoms and usually originate from nonliving sources. Your cells chemically convert between these kinds to hold out varied physiological capabilities.
Selenium deficiency is a big well being problem, notably in areas with selenium-poor soils, resembling components of China, Africa and Europe. Low selenium ranges are related to Keshan illness, a deadly coronary heart situation, and Kashin-Beck illness, which impacts joints and bones. Deficiency additionally weakens immune operate, rising susceptibility to infections.
Brazil nuts include notably excessive ranges of selenium.
R.Tsubin/Second by way of Getty Photographs
Consuming an excessive amount of selenium can also be a problem. Oversupplementation or extra environmental publicity can result in selenosis, a situation with signs resembling brittle hair and nails, digestive points, pores and skin rashes and neurological signs resembling irritability and fatigue. In extreme instances, selenium toxicity may end up in organ failure and loss of life.
Selenium has a slim therapeutic window, which is the dosage vary that gives secure and efficient therapy with minimal dangerous negative effects. For instance, selenium can both enhance or lower your physique’s immune operate, relying on the dose. Ample ranges of selenium strengthen your immune cells’ means to combat infections and tumors, whereas extreme selenium consumption can suppress immune responses by damaging immune tissues.
Selenium and most cancers prevention
Selenium could have the potential to deal with and stop most cancers.
Scientists have lengthy studied selenium’s position in most cancers prevention. Initially suspected to be a carcinogen, later research discovered it had protecting results in opposition to liver injury. Within the Sixties. researchers proposed that selenium might be used to forestall most cancers, an idea that gained additional traction within the Nineteen Nineties.
Nonetheless, large-scale scientific trials have produced blended outcomes. The Selenium and Vitamin E Most cancers Prevention Trial was a examine of over 35,500 males that ran from 2001 to 2004. They discovered that taking selenium each day didn’t scale back prostate most cancers threat and should even enhance the danger of prostate most cancers in males with already excessive selenium ranges.
Findings from a examine performed from 1983 to 1996, the Dietary Prevention of Most cancers Trial, steered selenium could shield in opposition to prostate and different cancers. However researchers additionally noticed a heightened incidence of nonmelanoma pores and skin most cancers amongst contributors.
These conflicting outcomes could also be as a result of completely different types of selenium every examine examined, in addition to variations in baseline selenium ranges amongst contributors. Different research have discovered that selenium-contaminated water in a municipality of Italy has been linked to an elevated threat of melanoma.
The antioxidant results of selenium fluctuate relying on its dose.
Razaghi et al./EJC, CC BY-SA
Selenium and most cancers therapy
Selenium can also have the potential to cease most cancers from spreading.
My analysis focuses on the potential of utilizing selenium to complement chemotherapy for most cancers therapy. Selenium compounds resembling methylseleninic acid, or MSA, and seleno-L-methionine, or SLM, present promise in focusing on proteins that drive tumor development and therapy resistance. Research from my staff and I’ve discovered that MSA can modulate key biochemical pathways associated to kidney most cancers by decreasing ranges of proteins that affect tumor development and immune evasion. We additionally noticed that SLM could gradual kidney tumor development in mice with out poisonous negative effects.
Extra considerably, in a Part 1 scientific trial, we discovered that combining SLM with the chemotherapy drug axitinib was efficient in treating metastatic kidney most cancers in sufferers, with minimal negative effects. Of the 27 sufferers we handled, over half noticed their tumors shrink in measurement, with a median total survival of practically 20 months. These findings counsel that selenium could have a synergistic impact on chemotherapy by making it simpler.
Additional investigation into how selenium could assist overcome therapy resistance and what doses are optimum will make clear its potential as a viable addition to most cancers therapy.
Hanging the suitable steadiness
Whether or not as an immune booster or potential therapy for illness, the importance of selenium in human well being is plain.
Consuming selenium-rich meals – resembling Brazil nuts, seafood, entire grains and eggs – can assist maintain optimum nutrient ranges. In areas with selenium-deficient soils, supplementation with medical supervision could also be crucial.
The effective line between profit and hurt underscores the significance of balanced consumption and personalised approaches to selenium supplementation. As analysis continues, I consider selenium’s multifaceted position in well being will grow to be extra clear.