Fighting cancer with flax seeds

Flaxseed is already well known for its ability to fight a range of ailments – from stomach problems to cardiovascular disease. Now, nutritional sciences professor Lilian Thompson is producing evidence that flaxseed helps fight breast cancer.

Thompson is one of the world’s experts on the pluses of flaxseed and other plant foods. “We have always known that plant foods are beneficial to health,” she says. “But I am interested in just what it is in the plants that promotes health.”

So she turned her attention to “lignans” – plant chemicals that are similar to the female hormone estrogen.

Other researchers found vegetarians have high concentrations of lignans in their urine, while breast cancer patients have low concentrations. “This indicated that maybe lignans could protect against breast cancer,” says Thompson. “But we didn’t know how much of the lignans were present in foods.”

To find out, Thompson screened 66 plant foods normally found in the vegetarian diet and discovered that flaxseed contains 75 to 800 times more lignans than most of the foods. She then tested flaxseed on carcinogen-treated rats, immuno-deficient mice with human tumours and, more recently, breast cancer patients. But flaxseed has many chemical compounds, so Thompson isolated the lignans from the flaxseed and also tested them.

With each subject group, breast cancer tumours were reduced in size, sometimes by as much as 50 per cent. And metastasis – the spread of cancer through the body – was also reduced.

“Our idea is that the lignans interfere with estrogen, which promotes tumour growth,” says Thompson. She has also found that the lignans work in harmony with anti-estrogen cancer drugs, unlike soy, which seems to negate the work of drugs in some studies.

Thompson isn’t finished. “We have only tested a small number of human patients, so we need to repeat the research with more. And we are interested in seeing if the lignans are made part of a baby’s diet and continued through childhood, whether they can fight breast cancer when the children become adults.”