​New York, May 27 (IANS) NASA has released a video to highlight its 'Twins Study' that investigates metabolic changes in retired US astronaut Scott Kelly and his twin brother Mark.

The video titled "Metabolomics: You Are What You Eat" and sixth in the mini-series of eight videos, provides a broad overview of ongoing Twins Study research on the International Space Station and the importance of the metabolome -- the collection of an individual's metabolites, NASA's Human Research Programme said on Thursday.

Metabolites are key small molecules. They're the chemicals in the body to let you do all the things you do. It's all these things that give you energy, like glucose. They let you move, think, and digest your food.

Using a mass spectrometer, researchers can analyse blood and urine for secreted metabolites. 

By following Scott and Mark Kelly both in space and on Earth, scientists can see a collection of changes occurring. Some chemicals are indicative of high stress but other chemicals are unknown. 

It is hoped that the Twins Study will show which stress molecules get activated at which times and what other kinds of metabolites are present and active. 

Identical twins share the same fertilised egg, thus, share similar genes. Because of similarities, researchers can focus on the metabolic changes.

Researchers believe that diet definitely impacts a person's metabolites. They can see which foods cause what kinds of metabolic changes and how that evolves over time. 

The study could be helpful for researchers creating recommendations to protect the health of astronauts embarking on long-duration missions, such as a journey to Mars, as well as benefit humans on the Earth.​