"The only supplement NASA gives crews is vitamin D, since astronauts don't get enough sunlight to make the vitamin in the usual way."
Sentence in article about what NASA plans to give crews going to Mars
How NASA Is Solving the Space Food Problem
See also Vitamin D Life
- 2000 IU daily raised vitamin D levels by 5 nanograms while on submarine patrol – July 2014
- Recommended increasing vitamin D for space flight – NASA Sept 2013
Astronauts might also need Magnesium supplementation
- What We Learned From The Accelerated Aging of Astronauts March 2012
"With space flight there are significant reductions of serum Mg (P<0.0001) that have been shown in large studies of astronauts and cosmonauts." - Magnesium and Space Flight Dec 2015
Bed rest as well as space flight increased Magnesium in pee
Wonder about increased need for Magnesium in people in bed much/all of the time
 Download the PDF from Vitamin D Life