Tag: Astronauts

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Want to be an Astronaut? Better Start Eating Your Fruits and Veggies Now

Even Astronauts in space get sick and NASA is trying to help them live healthier lives. In 2017, Researches at NASA, The University of Texas Medical Branch, and the J. Craig Venter Institute started a program to study how spaceflight impacts human physiology, the immune system, and the microbiota in the gut. Microbiota are organisms that live in your digestive tract that help to break down the food that you eat. Since diet is one of the few thing that NASA can actually control on spaceflights, the team designed an experiment to study diet of astronauts in a stimulation on earth. The scientist believed that eating more fruits and vegetables and things like omega-3 fatty acids and lycopene would actually improve the immune response, gut microbiota, and nutrition of astronauts. This improved diet should improve the health of the crew and reduce any negative physiological effects caused by space flight.

In order to perform this study, the researchers will compare what astronauts eat now on the International Space Station to the new diets that included more fruits and veggies. Four 45 day mission tests will be executed in a closed chamber that mimics flight in space. The participants will have bio sampling done both before and after their time in the simulation chamber. The research team plans to record dietary intake, immune markers, profiles of gut microbiomes, and nutritional status biomarkers and metabolites. After the data is collected, statistical evaluations will determine if the new diet improved the health of our astronauts. There has already been data collected from two crew members during the first mission, entitled Campaign 4 Mission 1. A second mission was attempted but the results were not valid because it had to be cut short due to the effects of Hurricane Harvey. After the completion of the study, the hope is that an improved diet will keep our astronauts healthier and hopefully ease the transition back to Earth!

 

LINK: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170008859.pdf

Douglas, G. L., Zwart, S. R., Young, M., Kloeris, V., Crucian, B., Smith, S. M., Lorenzi, H. 2018. The Integrated Impact of Diet on Human Immune Response, The Gut Microbiota, and Nutritional Status During Adaptation to a Spaceflight Analog. NASA Technical Reports Server. JSC-CN-40467.

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Putting Too Much Heart into Space Exploration? Cardiovascular Disease and Cancer in Astronauts

The effect of space radiation on astronaut health has always been a concern of NASA and its astronauts. With space flight, there are numerous possible health challenges that can occur, but radiation and its effect on cardiovascular disease and cancer is at the top of NASA’s list. The difficulties and costs of space travel make it hard to measure these effects. In spite of these challenges, in 2018 researchers at The University of Texas, National Cancer Institute, NASA Johnson Space Center, and MEI Technologies conducted an observational cohort study of astronauts and found that there was no over exaggerated risk of cancer or cardiovascular disease due to space radiation. However, these results were not completely conclusive and doubts still remain.

The team selected astronauts from 1959 to 1969 and looked at their medical records from birth to death, or 2016, which ever came first. Their data was collected from the Lifetime Surveillance of Astronaut Health program at the NASA Johnson Space Center. The astronauts that were used in the study participated in the Mercury through Space Shuttle programs.  A diverse population was not possible as all astronauts of the time were white males, and some of the included subjects never even flew a space mission.  In total, there were 73 white males (49 living and 34 deceased) that participated in the study.  The health hazards of smoking were not well known at the time, so this group maintained similar smoking patterns as the general U.S. population.  It would be much more difficult to find a single astronaut that smokes today! NASA carefully measures radiation exposure to its astronauts and the total doses ranged from 0 to 74.1 mGy (milligrays). After comparing with the United States white male population, the overall mortality rates of the astronauts that were used in the test fell well below the national average!

Although the researchers found that space radiation doesn’t lead to risk of cancer or cardiovascular disease, they decided that the findings were not conclusive, only because they used such a small sample. It is also possible that the astronauts in the population had a reduced cardiac risk because they were in better physical condition than the average U.S. white male of the time. The researchers want to look more into this topic by using epidemiology data with cell and animal studies to back up their findings on the risk of space radiation.

Link:  https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170009911.pdf

Elgart, S.R., Little, M. P., Campbell, L. J., Milder, C. M., Shavers, M. R., Huff J. L., Patel, Z. S. Radiation Exposure and Mortality from Cardiovascular Disease and Cancer in Early NASA Astronauts: Space for Exploration. NASA Technical Reports Sever: JSC-CN-40709.

 

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Space Headaches?! : NASA Looks at How Cephalad Fluid Shifts Affect Retinal Blood Vessels

On October 25th, 2017 (published by NASA in 2018), researchers at NASA’s Ames Research Center in Mountain View California explored the differences in pre and post vascular pressure in International Space Station Crew members and Head Down Tilted (HDT) Bed Rest patients. This study found that venous responses to these long-duration phenomena were marked by a decrease in vascular densities in the retinas of crew members and an increase in subjects after HDT. It is well known that long term space travelers experience “Space” headaches due to cephalad fluid shifts increasing fluid pressure in the upper body. Cephalad fluid shifts occur when an astronaut experiences more fluid then normal in their upper body due to the lack of gravity forcing the fluid down. This effect is easily seen in the puffy faces of astronauts in space.

Astronaut floating in space on the ISS
Astronaut Karen Nyberg floating in the International Space Station. You can somewhat see her puffier face in this image.

The researchers used a 30 infrared (IR) Heidelberg Spectralis® machine (a more advanced version of that fun puff test you get at the doctors) to determine that the vascular part of the retina in the eyes decreased in crew members after space flight yet increased in subjects after HDTBR. Pictures from Spectralis were looked at by VESGEN, a new automated software developed to discover vascular diseases in the retina and other tissue. The pictures created a map of blood vessel diameters and densities utilizing a new measure of vascular space-filling capacity called . The experiment used four people who experienced HDT and eight ISS crewmembers for the project. The VESGEN program performed two distinct tests on these individuals. Test one did not disclose if the left and right retinas were from the ISS travelers or HDT patients, while test two matched the pairs for each subject to display the effects of either HDT or space flight.

The researchers were surprised to see that 11 out of 16 retinas of the crew members’ space-filling capacity of their retinal vessels decreased and that 6 out of 10 retinas of the HDT patients vascular densities increased. The researchers believe that this difference mostly comes from lack of imaging that can capture smaller vessels rather than from vessel growth or decay. They also said that six months on the ISS compared to seventy days on HDT and the presence of microgravity and gravity may also have a large effect. However, there is still room to improve! The biostatistical and medical analyses of the images will have the final say on whether the VESGEN findings were correct or not.

OPINION: Who knew that main reason astronauts have space headaches was because of excess fluid on on their optic nerves! I think it’s very possible that VESGEN outcomes are true. As an aspiring optometrist myself, I found these results to be pretty cool. I’ve never really heard about the effects of almost no gravity on vision, but it makes sense right? Vision has to be compromised somehow with all of that extra fluid in the upper body. However it was a very small sample size so the VESGEN outcomes might be wrong, but then again its expensive to send people to space and hard to get people to do HDT for seventy days.

Link: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170009912.pdf

Murray, M.C., Vizzeri, G., Taibbi, G., Mason, S. S., Young, M. H., Zanello, S. B., and Parsons-Wingerter, P. A. 2018. Differences in Pre and Post Vascular Patterning of Retinas from ISS Crew Members and HDT Subjects by VESGEN Analysis. NASA Technical Reports Server: JSC-CN-40700.