WHAT WAS CLAIMED
Cancer cells cannot live in the presence of oxygen and can be starved with a low-sugar diet.
OUR VERDICT
False. Cancer cells can grow in oxygen and limiting dietary glucose won't affect their growth.
AAP FACTCHECK - Getting out into the countryside for more oxygen isn't an effective cancer treatment and cancer cells can't be "starved" by a low-sugar diet, contrary to claims online.
Experts say cancer cells live and grow in high-oxygen environments, and cutting back on sugar will not starve them.
The claim appears in an Instagram post from a Fijian user, who attributes her insights to a seminar by Barbara O'Neill, a naturopath who is permanently barred from providing health services in four Australian states.
The video is captioned: "Valuable points I gathered from Day 2 of Barbara O'Neil's (sic) Seminar on 'What Cancer Hates'."
AAP FactCheck has previously debunked multiple claims made by Ms O'Neill.
"Cancer cannot live in the presence of oxygen," the woman in the Instagram video said.
"So if you have cancer patients, take them out to the countryside or take them out to the village close to the beach."
"Have them … breathe oxygen, clean pure oxygen."
However, experts told AAP FactCheck the claim that increasing oxygen is an effective treatment is "inaccurate" and "crap".
Raul Mostoslavsky, an oncologist at Harvard University, said the claim that exposing cancer to oxygen was beneficial was "naive and overall inaccurate."
While cancer cells use glucose in an anaerobic manner without oxygen, he said, they can also process other fuels using oxygen.
"So, to claim that exposing cancer cells to oxygen is beneficial is not true," Prof Mostoslavsky told AAP FactCheck.
"Of note, except in very specific cases, breathing pure oxygen is toxic to the organism, so such a recommendation would be dangerous for people."
He also said getting outdoors to the beach or countryside did not correlate with "more oxygen", as the video implied, although he said less stressful environments can improve well-being.
Jeff Holst, a cancer expert from the University of NSW, labelled the claim as the "usual crap".
He said pure air contained about 21 per cent oxygen, while the level in most body tissue was less than 10 per cent.
While cancer cells often grow in "hypoxic" environments where oxygen levels are 1.0 per cent or less, Prof Holst said high levels do not inhibit their growth.
"How do we know this? In the lab, we actually grow cancer cells very well in 18 per cent oxygen, which is a level they never see in the body, and is not much different to pure air," he told AAP FactCheck.
"So they actually grow very well in high oxygen levels."
Later in the video, the Fiji user also claimed: "Cancer hates low glucose."
"You need to starve those cancer cells. Eat low sugar, no fruits for at least six weeks, and no chemicals," she said.
The experts said the claim was based on a misunderstanding of how cancer cells use glucose and other fuels.
Prof Mostoslavsky explained that cancer cells do not directly obtain glucose from the foods people eat.
"When you eat low glucose, the body will find ways to generate glucose, so you can't directly translate it as a good diet to 'starve' cancer cells," he said.
Prof Holst said cancer cells can also use many fuels other than glucose for growth.
"So just limiting glucose won't do the job," he said.
The Cancer Council said no diet could cure cancer and "there is little evidence that following a strict diet will have any added benefit."
Science Feedback has debunked similar claims about oxygen and glucose related to cancer treatment.
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