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.
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.
Low Blood Selenium and High Blood Cadmium Levels
In the US survey, the following significant associations were seen [Xing 2022]:
- Blood selenium levels were inversely associated with all-cause mortality and cardiovascular mortality.
- Blood cadmium levels were positively associated with all-cause mortality and cardiovascular mortality.
- Blood selenium levels were associated with a lower risk of cardiovascular mortality in individuals with heart failure.
The Link Between Cadmium and Heart Disease
In 40 years of cardiology practice, Dr. Dorph-Peterson made the following observations, presented here in abbreviated form from his 2017 autobiography:
- Yes, Dorph-Petersen acknowledges that stress, smoking, dietary intakes of animal fat (as opposed to fats from ocean fish), high cholesterol levels, too much sugar in the diet, and lack of exercise are all risk factors for heart disease.
- In most of the industrialized and urbanized world, iron pipes deliver the drinking water. Inevitably, iron pipes release cadmium into the drinking water. Studies show that cadmium intake is associated with increased risk of atherosclerosis [Xing 2022; Zwolak 2020].
- The problem of toxic cadmium in the drinking water is worse in regions of the world with low calcium content in the water. Over time, calcium in the water becomes deposited on the walls of the iron pipes and reduces the release of cadmium from the iron pipes into the drinking water. In regions with low calcium content in the water, there is a greater incidence of heart disease. This is otherwise somewhat counter-intuitive: one might expect that high calcium content in the drinking water would be a risk factor for heart disease.
- Toxic heavy metals such as cadmium and mercury are difficult to eliminate from the body once they come in. Over the years, the very small quantities of cadmium from the drinking water accumulate in the body.
- Other sources of cadmium intake are wild mushrooms, sunflower seeds, flax seed, and cigarette smoking. It may be that the cadmium content in tobacco is the reason why smoking is associated with considerably increased risk of heart disease.
- This gradual accumulation of toxic cadmium in the body is one of the primary causes of atherosclerosis. The mechanism of action seems to be that cadmium damages the walls of blood vessels and results in inflammation of blood vessels.
Selenium Protects Against Cadmium Toxicity
What was it that focused Dr. Dorph-Petersen’s attention on selenium as a possible prophylaxis for the prevention of cadmium poisoning?
- Pig farmers in Denmark had problems with atherosclerosis in their animals. By adding selenium to the feed, they reduced significantly the incidence of atherosclerosis. Dorph-Petersen knew that there are many similarities between pigs and humans in terms of anatomy and physiology, immune system, and genetic make-up [Dorph-Petersen 2017].
- In the 20th century in Japan and Greenland, especially before the people of Greenland began to deviate from their native eating habits to adopt a more typically Danish diet, there were much lower rates of atherosclerosis than in the rest of the industrialized and urbanized world. What was the difference? The Japanese and the people of Greenland ate much more ocean fish, and ocean fish contains much more selenium than other foods do.
- When people in Greenland began to eat less fish and more of a Danish diet, their rate of atherosclerosis increased dramatically, nearly catching up to the rate in Denmark [Dorph-Petersen 2017].
Selenium Protects by Sequestering Cadmium
Animal studies and cell culture studies show that various forms of selenium, e.g., selenite, selenomethionine, selenium-enriched yeast, or selenium from lentils, can reduce cadmium-mediated toxicity in the heart, liver, kidney, spleen, and brain. Selenium protects against the toxicity of cadmium mainly through the sequestration of cadmium into biologically inert complexes and/or through the action of selenium-dependent antioxidant enzymes [Zwolak 2020].
Conclusion: Selenium and Cadmium and Heart Disease
Atherosclerosis is the medical term for the deposit of plaque – fats, cholesterol and other substances – on the inside of artery walls. The accumulation of plaque causes arteries to become narrow, which blocks blood flow. If the plaque bursts, a blood clot results [Mayo Clinic Staff 2023].
Needed: clinical trials to correlate the level of cadmium in drinking water and the incidence of atherosclerosis.
Dr. Dorph-Petersen thinks that Denmark would be a good place to conduct such studies. In Denmark, there are still areas of the country in which the drinking water is delivered in iron pipes, there are areas with low and high calcium content in the drinking water, and there are good records of cause of death.
It remains to be seen whether there is a signficiantly higher prevalence of atherosclerosis in areas with relatively high cadmium concentrations in the drinking water.
Denmark and much of northern Europe and the United Kingdom have relatively low dietary intakes of selenium, i.e., ca. 48 mcg/day, and somewhat low serum selenium concentrations, i.e., ca. 95 mcg/L on average [Rasmussen 2011].
Sources
Dorph-Petersen A. Et Liv Som Læge. Dronninglund, DK: Queenswood Media Productions, 2017. ISBN: 978-87-91519-75-8.
Rasmussen LB, Schomburg L, Köhrle J, Pedersen IB, Hollenbach B, Hög A, Ovesen L, Perrild H, Laurberg P. Selenium status, thyroid volume, and multiple nodule formation in an area with mild iodine deficiency. Eur J Endocrinol. 2011 Apr;164(4):585-90.
Xing X, Xu M, Yang L, Shao C, Wang Y, Qi M, Niu X, Gao D. Association of selenium and cadmium with heart failure and mortality based on the National Health and Nutrition Examination Survey. J Hum Nutr Diet. 2022 Nov 2. doi: 10.1111/jhn.13107. Epub ahead of print.
Zwolak I. The Role of Selenium in Arsenic and Cadmium Toxicity: an Updated Review of Scientific Literature. Biol Trace Elem Res. 2020 Jan;193(1):44-63.
The information presented in this review article is not intended as medical advice and should not be used as such.
30 June 2023