EPA in fish oil found to halt tumor cell growth, increase rate of cancer cell “suicide”
by Craig Weatherby
We’ve reported on a number of epidemiological (population) studies that linked higher intake of fish or omega-3s to reduced rates of colorectal cancers (Just go to our archive and search for "cancer").
The results of a new investigation, published online last week, support those findings and help explain why omega-3s inhibit colon cancers.
Researchers at London’s St George's Hospital gave high doses of EPA—one of the two highly beneficial omega-3s in fish oil—to patients with the pre-cancerous colorectal tumors called adenomas.
Under a microscope, doctors can see two ominous developments in the colon lining (mucosa) of people with colorectal adenomas:
- Increased proliferation of so-called “crypt” cells, which are responsible for water reclamation.
- A decrease in the rate at which adenoma cells undergo the programmed cell death or “suicide” called apoptosis.
These twin phenomena are considered warning signs that their pre-cancerous colorectal tumors will advance to become deadly cancers that grow uncontrollably.
Study shows EPA may halt transformation of tumors to cancers
The London team recruited 30 patients and randomized them to take either two grams (2,000 mg) of pure EPA daily for three months, or to receive no treatment (Courtney ED et al 2007).
Biopsies were taken at the beginning of the study and three months later, and the tissues were analyzed for three things:
- Proliferation (division and growth) among crypt cells
- Rate of apoptosis (programmed cell death) among adenoma cells
- Fatty acid content of mucosal tissues
Compared with a lack of positive results in the control group, the outcomes in the EPA group were uniformly good: proliferation among crypt cells reduced significantly while the rate of apoptosis among adenoma cells rose significantly.
And as expected, the proportions of EPA in the EPA-supplemented group’s mucosal tissues rose significantly.
It would be interesting to repeat the experiment using DHA, the other omega-3 in fish oil, since an earlier study in rats showed that in those rodents, EPA and DHA both exert the positive effects seen in the new human trial (Calviello G et al 1999).
We suspect that the Brits chose to test EPA because it exerts stronger anti-inflammatory effects, and inflammation promotes cancer growth.
- Courtney ED, Matthews S, Finlayson C, Di Pierro D, Belluzzi A, Roda E, Kang JY, Leicester RJ. Eicosapentaenoic acid (EPA) reduces crypt cell proliferation and increases apoptosis in normal colonic mucosa in subjects with a history of colorectal adenomas. Int J Colorectal Dis. 2007 Jan 10; [Epub ahead of print]
- Calviello G, Palozza P, Maggiano N, Piccioni E, Franceschelli P, Frattucci A, Di Nicuolo F, Bartoli GM. Cell proliferation, differentiation, and apoptosis are modified by n-3 polyunsaturated fatty acids in normal colonic mucosa. Lipids. 1999 Jun;34(6):599-604.