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].
The serum selenium status in the sample of 3199 adults in the United States is interesting. The levels are much higher than what one would expect in much of Europe and the Middle East [cf. Stoffaneller & Morse 2015].
Quartile 1 below 115.1 mcg/L
Quartile 2 from 115.1 to 127.0 mcg/L
Quartile 3 from 127.0 to 139.1 mcg/L
Quartile 4 from 139.1 to 435.0 mcg/L
Median level: 127 mcg/L
Comparing Q1 to Q4 participants, the researchers observed the following outcomes of higher serum selenium status:
- All-cause mortality 0.69 (0.54, 0.89) = reduced odds 31%
- Heart disease mortality 0.66 (0.45, 0.99) = reduced odds 34%
The researchers saw a linear dose–response relation between serum selenium and mortality in the range: 89–182 mcg/L. Mortality risk declined as serum selenium status increased [Qiu 2022].
Selenium Status and Chronic Kidney Disease
Zhu et al analyzed serum selenium concentrations and all-cause mortality and cardiovascular mortality in 3063 adults with chronic kidney disease. They found that higher serum selenium concentrations were independently associated with a decreased risk of all-cause and cardiovascular disease mortality in patients with chronic kidney disease [Zhu 2023].
Again, the higher level of serum selenium in the US adults is interesting. Note that the quartiles in the sample of adults with kidney disease are higher than the quartiles in the sample of adults with diabetes.
Quartile 1 below 156.1 mcg/L
Quartile 2 from 156.1 to 181.7 mcg/L
Quartile 3 from 181.7 to 201.5 mcg/L
Quartile 4 from 201.5 to 734.8 mcg/L
The median (Inter Quartile Range) concentration of serum selenium was 181.7 (156.1, 201.5) mcg/L.
Comparing Q1 with Q4 participants showed the following effects on mortality [Zhu 2023]:
- All-cause mortality 0.684 (0.549–0.852), i.e., reduced odds 31.5%
- Cardiovascular disease mortality 0.513 (0.356–0.739), i.e., reduced odds 48.7%
Selenium Status and Hypertension
In a sample of adults with hypertension recruited in 2003–2004 and followed for mortality through December 31, 2015, Tan et al identified a U-shaped relationship between serum selenium concentrations and all-cause mortality and cardiovascular disease mortality [Tan 2021].
The breakout of the serum selenium quartiles was as follows:
Quartile 1: equal to or below 124 mcg/L
Quartile 2: from 125 to –135 mcg/L
Quartile 3: from 136 to 147 mcg/L
Quartile 4: equal to or above 148 mcg/L
The low mortality risk shown on the U-shaped curves relating serum selenium levels (the x-variable) to the risk of mortality (the y-variable) occurred [Tan 2021]:
- at 136 mcg/L for all-cause mortality
- at 130 mcg/L for cardiovascular mortality.
At the low points of mortality risk, the odds of all-cause mortality were 43% reduced and the odds of cardiovascular disease mortality were 67% reduced [Tan 2021].
Conclusion: Mortality Risk and Selenium Intake and Status
What do we fear as we get older? Heart disease, high blood pressure, diabetes, kidney disease – they are all on the list.
The NHANES surveys indicate that a selenium intake that corresponds to a serum selenium status of approximately 127 – 136 mcg/L is associated with a lower risk of all-cause mortality and cardiovascular disease mortality.
Note that Hurst et al have shown that daily supplementation with a high-selenium yeast for ten weeks will raise the plasma selenium levels of healthy men and women aged 50 – 64 years as follows [Hurst 2010]:
- 50 mcg/day: from 95.6 to 118.3 mcg/L
- 100 mcg/day: from 95.6 to 152.0 mcg/L
In the Hurst study, the men and women were getting approximately 55 mcg of selenium per day in their food [Hurst 2010]. Dietary intakes of selenium will vary considerably from region to region.
Sources
Hurst R, Armah CN, Dainty JR, Hart DJ, Teucher B, Goldson AJ, Broadley MR, Motley AK, Fairweather-Tait SJ. Establishing optimal selenium status: results of a randomized, double-blind, placebo-controlled trial. Am J Clin Nutr. 2010 Apr;91(4):923-31.
Qiu Z, Geng T, Wan Z, Lu Q, Guo J, Liu L, Pan A, Liu G. Serum selenium concentrations and risk of all-cause and heart disease mortality among individuals with type 2 diabetes. Am J Clin Nutr. 2022 Jan 11;115(1):53-60.
Stoffaneller R, Morse NL. A review of dietary selenium intake and selenium status in Europe and the Middle East. Nutrients. 2015 Feb 27;7(3):1494-537.
Tan QH, Huang YQ, Liu XC, Liu L, Lo K, Chen JY, Feng YQ. A U-Shaped relationship between selenium concentrations and all-cause or cardiovascular mortality in patients with hypertension. Front Cardiovasc Med. 2021 Jul 30;8:671618.
Zhu D, Zhong Q, Lin T, Song T. Higher serum selenium concentration is associated with lower risk of all-cause and cardiovascular mortality among individuals with chronic kidney disease: A population-based cohort study of NHANES. Front Nutr. 2023 Mar 31;10:1127188.
The information presented in this review article is not intended as medical advice. It should not be used as such.
15 December 2023