The Cancer Chronicles

Fabulous Flax: The Protective Effects of Ground Flaxseed and Flaxseed Oil Against Cancer

Flax seeds and flaxseed oil are inexpensive, readily available foods that we can eat daily to prevent various cancers. The following studies demonstrate their effectiveness, particularly in preventing or slowing the growth of breast and colon cancer.


In studies on mice that had been injected with breast cancer cells that were not responsive to the hormone estrogen, a diet of 10% flaxseed caused a reduction in the breast cancer tumour growth rate and a 45% reduction in total spread of the cancer to other sites (metastases) compared to mice fed a regular diet that did not include flaxseed. Lung metastases were reduced by 82% in the mice fed flaxseed and lymph node metastases was reduced even further. Flaxseed inhibited human breast cancer cell growth and spread in mice when included as 10% of their diets.1  A second study on mice found that flaxseed oil also reduces spread of breast cancer cells to distant lymph nodes.2

A 2005 study on postmenopausal women who were patients at Princess Margaret Hospital in Toronto revealed that if women ate one muffin a day containing 25 grams of flaxseed beginning at the time of their breast cancer diagnosis and continuing until their surgery (about a month later) there was a 31% increase in cancer cell death (apoptosis) in their tumours compared to women who ate a muffin that did not contain flaxseed. Simple inclusion of flaxseed in the diets of women with breast cancer can slow down tumor growth.3


Cancer often arises after spontaneous genetic damage, caused either by mutations or errors due to factors such as radiation, free radical damage, heavy metal toxicity, chemical exposure, barbecued meat and cooked fats. Diets higher in fruits, vegetables, grains and omega 3 oils such as flaxseed and fish oil are associated with lower rates of cancer; while diets higher in animal protein, sugar and saturated, omega 6 or hydrogenated fats lead to more cancers.

Many components in fruits, vegetables and grains have anti-cancer effects. One study looked at the number of broken chromosomes found in the blood of rats before, during and after six weeks of a diet supplemented with 20% fruits and vegetables and flaxseed. It was determined that of all the foods tested, flaxseed was the most protective in reducing chromosomal damage and did so by a whopping 30%.4 From this study we can be confident in knowing that if we include fruits and vegetables as at least 20% of our diets and eat at least 2 tablespoons of ground flaxseed daily, we can decrease our risk of cancer.


Colon cancer is the third most commonly diagnosed cancer in Canadian women and men. If we each consume 2-4 tablespoons of fresh flaxseed oil daily and decrease our consumption of omega 6 oils such as corn, safflower and sunflower oils, we can reduce our risk of colon cancer. In one study, rats were fed a diet that included either 15% corn oil or 15% flaxseed oil. The animals were then injected once weekly with a chemical known to cause colon cancer for three weeks. Thirty-five weeks later autopsies revealed that all of the rats on the corn oil diet had colon cancer tumours while only 54% of the rats on the flaxseed oil diet developed tumours, despite exposure to the same carcinogen. Among all the rats that did develop colon cancer tumours, there were over four times as many tumours in the rats that consumed the corn oil as there were in rats that ate flaxseed oil. The size of the tumours was also larger in the corn oil group.5 Therefore we can decrease our likelihood of developing colon cancer by consuming unheated, refrigerated flaxseed oil daily. I recommend the Flora brand of flaxseed oil because it is stored in dark glass rather than plastic bottles.

In another study, mice were implanted with human colon cancer cells. The mice were then injected three times weekly with a cancer fighting component of flaxseed called enterolactone. The injections of enterolactone strongly inhibited the growth of colon cancer cells with no negative side effects.6


Follow the tips below to utilize these super foods:


1. Buy organic seeds whenever possible, usually found at a health food store. You can choose either the golden or brown seeds.

2. Get yourself a small electric coffee grinder and grind the seeds before eating them, so you can absorb them. Eat them within 15 minutes of grinding so that the oil does not go rancid upon exposure to air. Do not buy them already ground and do not store them in the fridge for the next day – eat them freshly ground each time.

3. Add the ground seeds to fruit smoothies; mix a little in apple sauce; toss them on salad; add them to a pancake mix; stir them in a bean soup just before you serve the soup; mix them in with vegetable juice; bake them in muffins. Aim to have at least 2 tablespoons daily.

Flaxseed Oil

1. Buy cold-pressed organic flaxseed oil. It should always be stored in the fridge and ideally should be in a glass container. The Flora brand is a good one and readily available in health food stores.

2. Look at the pressing date on the bottle and make you use it up before the expiry date. Flaxseed oil easily goes rancid upon exposure to light, heat and air and loses its benefit. You can add 2 capsules of vitamin E oil to the bottle by piercing the capsules and squirting them in with the flaxseed oil to keep it fresher for longer.

3. Store the oil in the fridge or freezer, and put the cap on tightly immediately after each use.

4. Never heat or cook flaxseed oil.

5. Add it to smoothies; use it as a substitute for butter on toast or a baked potato; pour it on rice; add it to your soup bowl as you serve the soup; use it in salad dressing; add it to hummus; or just take it off the spoon. Aim to have at least 2 tablespoons daily.


1. Chen J, Stavro PM, Thompson LU. “Dietary flaxseed inhibits human breast cancer growth and metastases and downregulates expression of insulin-like growth factor and epidermal growth factor receptor.” Nutr Cancer. 2002;43(2):187-92.

2. Wang L, Chen J, Thompson LU. “The inhibitory effect of flaxseed on the growth and metastasis of estrogen receptor negative human breast cancer xenografts is attributed to both its lignan and oil components.” Int J Cancer. 2005 Sep 20;116(5):793-8.

3. Thompson LU, Chen JM, Li T, et al. “Dietary flaxseed alters tumor biological markers in postmenopausal breast cancer.” Clin cancer res. 2005 May 15;11(10):3828-35.

4. Trentin GA, Moody J, Torous DK et al. “The influence of dietary flaxseed and other grains, fruits and vegetables on the frequency of spontaneous chromosomal damage in mice.” Mutat Res. 2004 Jul 13;551(1-2):213-22.

5. Dwivedi C, natarajan K, Matthees DP. “Chemopreventive effects of dietary flaxseed oil on colon tumor development.” Nutr Cancer. 2005:51(1):52-8.

6. Danbara N, Yuri T, et al. “Enterolactone induces apoptosis and inhibits growth of Colo 201 human colon cancer cells both in vitro and in vivo.” Anticancer res. 2005 May-Jun;25(3B):2269-76.

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