Tag: Toxicity

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Selenium from Selenium-Enriched Yeast

Selenium from selenium-enriched yeast supplements is more bioavailable than selenium from an inorganic source such as sodium selenite. Selenium from selenium-enriched yeast supplements also tends to be less toxic. These are the conclusions from a 2008 evaluation undertaken by a European Food Safety Authority (EFSA) scientific panel [EFSA 2008].

Glass of beer
Manufacturers use the yeast Saccharomyces cerevisiae — also known as brewer’s yeast — to produce selenium-enriched yeast supplements.

To quote directly from the report:

“Despite the higher bioavailability of selenium from organic sources such as selenium-enriched yeast, the toxicity of these organic forms has been shown in a number of studies in experimental animals to be lower than that of inorganic selenite or selenate.”

Study data indicate that organic selenium is more bioavailable than inorganic selenium. Studies in which different selenium preparations have been compared head-to-head point towards a higher bioavailability of selenium from yeast than from inorganic sources [Hadrup & Ravn-Haren 2021]. read more

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Selenium Protects Against Cadmium Poisoning and Atherosclerosis

Cadmium leaking from iron water pipes into drinking water may be a primary cause of increased risk of atherosclerosis – the increased risk of a buildup of plaque on the inside of the artery walls with inflammation as a consequence. This is the thesis of the Danish cardiologist Anton Dorph-Petersen.

Heart attack
Cadmium from drinking water accumulates in the body and causes damage to the layer of cells lining the inside of arteries, leading to a buildup of plaque and to increased risk of atherosclerosis and heart attack. Cadmium is a heavy metal that is found everywhere in the earth. Cadmium accumulates primarily in the liver and kidneys with toxic effects on the kidneys in particular. People with insufficient selenium and iron accumulate more cadmium. Cadmium takes a long time to be eliminated from the body. Iron water pipes and cigarette smoking are significant sources of cadmium in the body.

Dr. Dorph-Petersen asserts that the danger of cadmium toxicity is greatest in regions of the world in which the selenium content of the soil and plants is low and in regions of the world in which there is low dietary intake of selenium containing fish [Dorph-Petersen 2017].

Let me lay out Dr. Dorph-Petersen’s reasoning step by step. His hypothesis has not yet been verified by clinical trials.

However, we do know from a survey of 15,689 study participants in the US that low blood selenium and high blood cadmium are independent risk factors for heart failure. read more

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Selenium and Mercury Toxicity

A plate of salmon.
Eating fish will give pregnant women and children selenium and other nutrients that will promote the children’s growth and development. Eating fish may give adults heart health benefits. However, some ocean fish contain more mercury than selenium and should therefore be avoided. Consequently, the US Food and Drug Administration advises against eating meals from predatory whales, sharks, swordfish, king mackerel, marlin, orange roughy, tilefish, and big-eye tuna. Most other ocean fish will have more selenium than mercury in their tissues and should be safe, even advisable, to eat.

The selenium in our cells is the molecular “target” of toxic mercury. Inhibition of the normal biological activity of seleno-enzymes is the mechanism by which mercury damages our cells, most particularly our brain and nerve cells [Ralston & Raymond 2018].

Conceiving of selenium as the “target” of mercury leads to a better understanding of mercury toxicity than the old theory of selenium as the “tonic” that binds toxic mercury in a form that is no longer harmful [Ralston & Raymond 2018].

Professor Nicholas Ralston and consultant Lisa Raymond have done a review of the research literature about the characteristics of mercury toxicity to identify the selenium-dependent aspects of mercury’s biochemical mechanisms and effects. Their conclusions [Ralston & Raymond 2018]: read more