In the first finding, published in Clinical Chemistry, researchers measured selenium levels and found that those who survived the nine-year follow-up period had started the study with higher blood-fluid (plasma) levels of selenium than those who died. The researchers took into account diet, health and lifestyle and found that those with the lowest selenium levels were most likely to have died and that cancer was more likely to be the cause of death than other causes.
In the second finding, published in the Journal of Nutritional Biochemistry, compared to all other participants, those who were oldest, those who were obese and those who had heart or blood-vessel disease during the nine-year follow-up period had lost the most selenium by the end of the study. Doctors found that other risk factors such as gender, education, smoking, drinking alcohol, high cholesterol and other blood fats, diabetes, and high blood pressure did not appear to decrease selenium levels and suggested that nutrition and metabolism may affect selenium levels.
In the third finding, among those whose selenium levels decreased over the nine-year period, those with the largest decrease had more mental decline than those with the smallest decrease. Among those whose selenium levels increased during the study, those with the smallest increase had more mental decline than those with the largest increase.
The EVA scientists concluded that selenium levels decline with age, low selenium levels make it difficult to maintain optimum health and selenium may protect against cardiovascular diseases and mental decline.