Researchers have claimed through a study published in the Journal of Nutritional Biochemistry that omega-3s from fish better at cancer prevention than those obtained from flaxseed and other oils.
Researchers at University of Guelph discovered that marine-based omega-3s are eight times more effective at inhibiting tumour development and growth than those extracted from seeds.
There are three types of omega-3 fatty acids: a-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA is plant-based and found in such edible seeds as flaxseed and in oils, such as soy, canola and hemp oil. EPA and DHA are found in marine life, such as fish, algae and phytoplankton.
For the study researchers fed the different types of omega-3s to mice with a highly aggressive form of human breast cancer called HER-2. HER-2 affects 25per cent of women and has a poor prognosis. Researchers exposed the mice to either the plant-based or the marine-based omega-3s, beginning in utero, so as to compare how effective the fatty acids are at prevention of cancer.
Researchers found overall exposure to marine-based omega-3s reduced the size of the tumours by 60 to 70 per cent and the number of tumours by 30 per cent. However, higher doses of the plant-based fatty acid were required to deliver the same impact as the marine-based omega-3s.
Omega-3s prevent and fight cancer by turning on genes associated with the immune system and blocking tumour growth pathways.
Based on the doses given in the study, researchers said humans should consume two to three servings of fish a week to have the same effect. Besides certain foods containing EPA and DHA, supplements and functional foods, such as omega-3 eggs or DHA milk, can offer similar cancer prevention effects, he added.