The association between the risk of heart disease and dietary intakes of selenium remains unclear. Here we report the results of some of the recent observational studies on this topic.
Risk of Cardiovascular Disease
Selenium Status and Mortality Risk
Mortality and morbidity. As we get older, we start to think about ways to reduce the risk of an early death. We want to reduce the risk of living out our lives in ill health.
We think about diet, exercise, 10,000 steps a day, hobbies, social contact. But, do we think about our selenium intake and status? Now, some large survey studies conducted in the US have shown that higher selenium status is significantly associated with lower mortality.
Each year, the National Health and Nutrition Examination Survey (NHANES) in the United States conducts surveys that focus on different population groups or health topics. This week, we present data from studies of selenium status and mortality.
Selenium Status and Type 2 Diabetes
Qiu et al examined the data from 3199 adults with type 2 diabetes. Their analysis showed that higher serum selenium concentrations are associated with lower all-cause mortality and lower heart disease mortality among individuals with type 2 diabetes [Qiu 2022].
Selenium Supplementation and Preeclampsia Risk
Selenium supplementation of pregnant women at a high risk of preeclampsia has shown beneficial effects on 1) serum selenium levels, 2) some metabolic profiles, 3) uterine artery pulsatility index, and 4) mental health, compared to placebo. The study compared the effect in 60 pregnant women of supplementation with 200 mcg/day for 12 weeks with the effect of placebo for the same period.
The supplementation took place for 12 weeks starting in weeks 16 to 18 of pregnancy. No side effects related to the intake of 200 mcg of selenium per day by pregnant women at high risk of preeclampsia were reported throughout the duration of the study [Mesdaghinia 2022].
Selenium Supplementation Compared to Placebo
How did the selenium supplementation compare with the placebo supplementation in the pregnant women?
Serum Selenium Status and Mortality Risk in Individuals with Hypertension
Serum selenium concentrations show a U-shaped association with all-cause mortality and with cardiovascular mortality in individuals with hypertension [Tan 2021].
This conclusion is based on an analysis of data from 929 individuals diagnosed with hypertension [Tan 2021].
- The average age of the individuals was 63 years plus/minus 13 years.
- Slightly more than half of the individuals were male: 53%.
- The researchers followed the individuals for a mean period of slightly more than ten years: 121 months plus/minus 41 months.
- During the follow-up period, 307 individuals died, including 56 individuals who died from cardiovascular disease.
Quartiles of Serum Selenium Status
For purposes of analysis, the researchers categorized the individuals with hypertension into quartiles of serum selenium concentration [Tan 2021]:
Q1: equal to or less than 124 mcg/L
Q2: 125-135 mcg/L
Q3: 136-147 mcg/L
Q4: greater than 148 mcg/L
Optimal Serum Selenium Levels in Individuals with Hypertension
The researchers compared the data from the serum selenium quartiles and found that the risk of death from all causes and death from heart disease were lowest in the third quartile (serum selenium concentrations between 136 and 147 mcg/L) [Tan 2021].