Vitamin C fights cancer, but not how we thought

Washington: Vitamin C can help to prevent cancer, but not the way that scientists thought, according to a study published Monday in the US.
Scientists have long thought that vitamin C and other antioxidants help to fight cancer growth by grabbing volatile oxygen free radical molecules and preventing them doing damage to DNA. But researchers at Johns Hopkins University in Baltimore found that antioxidants play a different role in the fight: they destabilize a tumor’s ability to grow under oxygen-starved conditions.
The researchers happened on this new role by observing mice which had been implanted with one of two types of cancer which produce high levels of free radicals, which can be suppressed by feeding the mice supplements of antioxidants, such as vitamin C.
When the Hopkins team examined cancer cells from mice that had been implanted with cancer but not fed antioxidants, they noticed there was no significant DNA damage.
“If DNA damage was not in play as a cause of the cancer, then whatever the antioxidants were doing to help was also not related to DNA damage,” said Ping Gao, one author of the study.
That conclusion led Gao and Dang to suspect that some other mechanism was involved, such as a protein known to be dependent on free radicals called HIF-1 (hypoxia-induced factor). The researchers found that HIF-1 was abundant in untreated cancer cells taken from the mice, but disappeared in vitamin C-treated cells.
“HIF-1 helps an oxygen-starved cell convert sugar to energy without using oxygen and also initiates the construction of new blood vessels to bring in a fresh oxygen supply,” explained Chi Dang, who also worked on the research. AFP

Spinach, eggs ward off blindness cause

Chicago: Two nutrients found in eggs, spinach and other leafy green vegetables offer some protection against the most common cause of blindness among the elderly, researchers said on Monday.
The two nutrients, lutein and zeaxanthin, are both carotenoids — compounds that give many fruits and vegetables a yellow colour.
They help ward off the condition, apparently by allowing the eyes to filter harmful short-wavelength light and by curtailing other damaging effects to the macula, or the center of the eye’s retina, the researchers said.
“No clear associations with other nutrients were seen,” including the vitamins C and E and beta-carotene, according to the researchers, led by John Paul SanGiovanni of the National Eye Institute, one of the National Institutes of Health in Maryland.
The 6-year study asked about the dietary habits of 4,519 people aged 60 to 80 when enrolled