Jett, who was autistic, died in 2009 after having a seizure whilst in the bath and hitting his head. The family was at their holiday home on Grand Bahama Island at the time.
Kelly, 50, talked about Jett on The Doctors TV show in America, and spoke of the apparent dangers in the environment that she believes contributed to Jett's autism, as well as the Kawasaki disease he had suffered since infancy.
Kelly also cited her 'fast and hard' labour, and the antibiotics she had to take while breastfeeding which gave Jett thrush, which some studies have linked (in the form of the Candida yeast infection) to the symptoms of autism.
"I strongly believe as a mother, as does my husband, that there are certain contributing factors that lead to autism and some of it is very much the chemicals in our environment and in our food," People quotes her as saying on the show.
Kelly discussed the chemicals we are routinely bombarded with, and spoke of her desire to educate other parents about the benefit of an organic lifestyle, saying she wants every mum and dad to know about the toxins that could make children ill.
Kelly and John Travolta are also parents to 12-year-old Ella, and since Jett's death, have had another son, Benjamin, who is now two.