Professor Jørgen Clausen, long-time professor in the Institute for Life Sciences and Chemistry, Roskilde University Center, in Roskilde, Denmark, was one of the early researchers to do clinical studies of the effects of supplementation with selenium. As such, it seems instructive to go back and look at the research done by Dr. Clausen and his colleagues at the end of the 20th century.
Professor Clausen’s selenium studies
Basically, Professor Clausen’s research can be described in five different categories:
- Effect of selenium supplementation on the health of the elderly nursing home residents
- Effect of selenium supplementation on the health of cigarette smokers
- Effect of selenium supplementation on the health of patients with chronic neurologic disorders
- Effect of selenium supplementation on the toxic effects of lead poisoning
- Effect of selenium supplementation on the activity levels of the selenium-dependent antioxidant enzyme glutathione peroxidase
In addition, Professor Clausen was an early leader in the investigation of the absorption and health effects of various forms of inorganic and organic selenium supplements.
Selenium supplementation and smokers and oxidative stress
To understand Dr. Clausen’s interest in the effect of selenium supplementation on smokers, we must first understand the concept of oxidative stress and the related concept of oxidative damage. Oxidative stress occurs when, in the process of metabolism of oxygen, the body produces, as a by-product, various reactive oxygen species (for example: peroxide, superoxide, hydroxyl, and singlet oxygen radicals) to excess.
Why excess? Because, in moderation, the free radicals do play a helpful role in cell signaling and cell homeostasis. When, however, the quantities of free radicals greatly exceed the availability of antioxidants to neutralize the free radicals, the free radicals can and do cause extensive structural damage to cells, to DNA, and to lipids.
Selenium and Vitamin E and smokers
Professor Clausen investigated the effect of daily supplementation with 200 micrograms of selenium and 1000 milligrams of Vitamin E (500 milligrams twice a day) in a ten-day intervention study. He knew that the rate of respiratory burst – the rapid release of reactive oxygen species – is significantly higher in smokers than in non-smokers. His intervention study, carried out on 10 smokers and 10 non-smokers, both men and women, aged 20 – 45 years, showed that the supplementation with the two antioxidants, selenium and Vitamin E, resulted in significant reductions in the rate of respiratory burst in smokers. Based on his findings, Professor Clausen recommended that smokers take daily selenium and other antioxidant supplements to limit the extent of oxidative damage to their lungs.
Selenium supplementation and the elderly and the ageing process
To test the effect of the supplementation of 97 elderly nursing home residents with a daily antioxidant cocktail, Professor Clausen carried out a 12-month randomized, double-blind, placebo-controlled study. The elderly residents’ average age was 75.3 years (range: 50 – 94 years). The antioxidant cocktail consisted of the following components:
- 300 micrograms of selenium
- 45 milligrams of zinc
- 2.7 milligrams of vitamin A
- 6 milligrams of vitamin B-6
- 270 milligrams of vitamin C
- 465 milligrams of vitamin E
- 250 milligrams of gamma-linolenic acid
The supplementation increased the residents’ whole blood levels of selenium and the levels of glutathione peroxidase antioxidant enzyme activity in their red blood cells compared with pre-supplementation levels and compared with levels in the placebo group participants.
The results of the selenium supplementation were statistically significant:
- reduced levels of lipofuscin in red blood cells as compared to pre-treatment values (lipofuscin = build-up of pigment granules that is considered to be a biological marker of ageing)
- improvement in psychological scores
- general improvement in blood flow assays in different areas of the brain surface
Selenium supplementation and chronic neurologic disorders
Multiple sclerosis
Professor Clausen and colleagues examined patients with multiple sclerosis (MS) and discovered significantly reduced selenium values and reduced glutathione peroxidase activity levels in various types of cells originating in the blood or carried in the blood. These cells also showed evidence of increased levels of oxidative damage.
In a non-blinded study, the Roskilde University Center researchers found that daily supplementation with a combination of selenium, vitamin C, and vitamin E normalized the MS patients’ blood cell abnormalities.
Batten’s disease
In a related study of selenium and antioxidant supplementation of patients with Batten’s disease, a recessive inherited neuro-degenerative disorder that is characterized by progressive loss of vision, epilepsy, and dementia, Professor Clausen found that the Batten’s disease patients had low selenium status and low glutathione peroxidase activity levels in cells in the blood. As was the case with the MS patients, the researchers were able to use selenium and other antioxidants to normalize the biochemical abnormalities of the batten’s disease patients.
The researchers pointed to similar Finnish clinical studies that indicate that an antioxidative treatment including selenium as the main component can inhibit the progression of the mental deterioration. The available data from the intervention with selenium and other antioxidants are relevant to the theory that Batten’s disease may be caused by increased oxidative damage to the cellular membranes.
Selenium supplementation and the toxic effects of lead
Early on in his career, Professor Clausen did some animal studies (rats) to see whether selenium supplementation might protect against the toxic effects of lead in the same way that selenium supplementation protects against the toxic effects of methylmercury. The results of his experiments indicated that selenium does protect against the toxic effects of lead.
In future articles on this website, we will want to look at more recent research on the relationship between selenium and heavy metals in the body.
Professor Clausen: a pioneer in selenium supplementation research
Professor Jørgen Clausen in Denmark, together with Professor Matti Tolonen in Finland, was among the earliest bio-medical researchers to realize the need selenium supplementation in regions with selenium-poor soil.
Sources
Clausen, J., Nielsen, S. A., & Kristensen, M. (1989). Biochemical and clinical effects of an antioxidative supplementation of geriatric patients. A double blind study. Biological Trace Element Research, 20(1-2), 135-151.
Clausen, J. (1992). The influence of antioxidants on the enhanced respiratory burst reaction in smokers. Annals of the New York Academy of Sciences, 669, 337-341.
Clausen, J. (1991). The influence of selenium and vitamin E on the enhanced respiratory burst reaction in smokers. Biological Trace Element Research, 31(3), 281-291.
Clausen, J., Jensen, G. E., & Nielsen, S. A. (1988). Selenium in chronic neurologic diseases. Multiple sclerosis and Batten’s disease. Biological Trace Element Research, 15179-203.
Jensen, G. E., Gissel-Nielsen, G., & Clausen, J. (1980). Leucocyte glutathione peroxidase activity and selenium level in multiple sclerosis. Journal of the Neurological Sciences, 48(1), 61-67.
Jensen, G. E., & Clausen, J. (1983). Leucocyte glutathione peroxidase activity and selenium level in Batten’s disease. Scandinavian Journal of Clinical and Laboratory Investigation, 43(3), 187-196.
Rastogi, S. C., Clausen, J., & Srivastava, K. C. (1976). Selenium and lead: mutual detoxifying effects. Toxicology, 6(3), 377-388.
Shukla, V. K., Jensen, G. E., & Clausen, J. (1977). Erythrocyte glutathione perioxidase deficiency in multiple sclerosis. Acta Neurologica Scandinavica, 56(6), 542-550.