Updated December 29, 2014.

Flaxseed, or linseed, is an ancient grain that may have originated in Egypt. The seeds, oil and seed meal can be used in many ways. Flaxseeds contain phytoestrogens, which may reduce your risk of breast cancer and possibly prevent a recurrence. The fibers from the flax plant have been used in linen fabric, yarns and bandages.

Dietary Benefits from Flaxseeds
Flaxseeds have two anticancer components: lignans and an omega-3 fat called "alphalinolenic acid" (ALA).

You may be familiar with flaxseeds as they are used as a natural laxative, a good source of dietary fiber and in preparations that help lower your cholesterol. Flaxseeds may also be helpful in reducing your risk of heart disease, osteoporosis, breast and endometrial cancers. Flaxseed oil has been used for the relief of hot flashes, breast pain, arthritis pain, and pain related to constipation.

Anticancer Action of Flaxseeds
Several studies have been done to determine how the phytoestrogens in flaxseeds may help cancer. One theory compares the estrogen-receptor blocking ability of flaxseeds with estrogen-receptor modulation drugs. The weak plant-based estrogens block the estrogen receptors on cells within breast tissue, starving them of full-strength female estrogen, possibly stopping tumor growth and preventing cell damage. This effect may be most effective for younger, premenopausal women with estrogen-receptor negative cancers. A clinical trial combining flaxseeds with a macrobiotic diet has been done by the National Center for Complementary and Alternative Medicine.

Among other goals, the study hopes to find out whether a macrobiotic diet that includes flaxseed will be beneficial during and after breast cancer therapy.

Breaking Down the Bounty from Flaxseeds
Flaxseeds are about the size of sesame seeds, but despite their small size, they are packed with great anticancer powers. The two most notable anticancer components of flaxseeds are lignans and alphalinolenic acid (ALA). Dietary fiber in flaxseeds and flaxseed oil is also of great benefit to your digestion.

• Dietary Fiber: Freshly ground flaxseeds are a good source of dietary fiber. You can sprinkle these on breads, cereals, soups and salads to lower your cholesterol and your risk of heart disease while keeping your tummy happy. Fiber from flaxseeds helps reduce constipation, but must be used with plenty of fluids. Add flaxseed oil to salad dressings or mix it with a smoothie.
• Lignans: Flaxseeds and sesame seeds are both great sources of lignans, a plant-based estrogen. Lignans may act as weak estrogens, fitting in to estrogen receptors on cells in breast and endometrial tissues. This action may protect cells that may become damaged or become cancerous when in contact with powerful female estrogens.
• Alphalinolenic acid (ALA): An omega-3 fatty acid, alphalinolenic acid is not made in your body, but must come from food. Omega-3 fatty acids are polyunsaturated fats that help reduce inflammation. When omega-3s are part of a well-balanced diet, and including vitamin C, vitamin E beta-carotene and selenium, they may be most effective in preventing and even treating breast cancer.

Easy Ways to Add Flaxseed to Your Diet
Here are some quick ways to add flaxseeds to your food:

• Sprinkle flaxseeds over salads and on cooked vegetables.
• Top off baked breads and muffins with ground flaxseeds in the last few minutes of baking.
• Include flaxseed meal in batter for waffles, pancakes, banana bread and whole wheat rolls.
• Stir some flaxseed oil in to your salad dressing and blend it in to a smoothie.

Some Cautions When Using Flaxseed
If you're taking flaxseed as a laxative, drink plenty of water to avoid constipation or intestinal blockage, as the seeds expand during digestion. Your body needs time to absorb the components of flaxseed, so wait a while before taking any other supplements or medications. Avoid flaxseed oil if you are allergic to flax or if you are pregnant or nursing. If you've had estrogen-receptor positive breast cancer, use flaxseed products in moderation.
<sub>Sources:
National Center for Complementary and Alternative Medicine. National Institutes of Health. Herbs at a Glance. Flaxseed and Flaxseed Oil. Last modified: October 22, 2008.

National Center for Complementary and Alternative Medicine. Clinical Trials. Macrobiotic Diet and Flax Seed: Effects on Estrogens, Phytoestrogens, & Fibrinolytic Factors. Completed in August 17, 2006. Results not yet available.</sub>