Selenium helps maintain the muscle strength of the over-eighties
A diet with enough selenium can help you maintain your muscle strength as the years go by. This is suggested by an epidemiological study published by British researchers at Newcastle University in Nutrients.Study
The researchers used data from 791 participants in the Newcastle 85+ Study. The researchers followed the study participants, all of whom were at least 85 years old, for 5 years. During the study, the researchers measured the muscle strength of the participants several times.

The participants had to squeeze a dynamometer with as much strength as possible, so the researchers could determine the hand grip strength of the study participants. In addition, the participants had to get up from a chair in the shortest possible time, walk forward three meters, turn around, and then sit back in the chair. This is the timed up & go test.When the study started, the researchers measured how much selenium the study participants ingested daily. The figure below shows that the intake taken in general was woefully low. Just over half of participants had an intake that the researchers described as low.
Click on the figure for a larger version.

The study participants lost strength in their hands during the study, but during the period, the subjects with an adequate selenium intake had more hand grip strength than the study participants in the other groups.

To a lesser extent, the researchers found a similar relationship between selenium intake and the outcome of the timed up & go-test.When the researchers determined whether their relationships were significant with multivariate statistics, they found that this was not the case. That is, they suspect, because they only had data on selenium intake at the beginning of their study.
"Inadequate dietary selenium intakes were common in very old adults", the researchers summarize.

"Low selenium intakes were associated with poorer hand grip strength and timed up & go performance in thecross-sectional analyses and in the unadjusted prospective analyses in all individuals, but not after accounting for other covariates. This is likely due to the limited dietary assessments only available at baseline or the proxy measure of selenium status using intakes rather than serum or plasma selenium."
"Future studies could measure selenium status as well as intake and continue these throughout the study duration."
Nutrients. 2020 Jul 12;12(7):E2068.