By Martine Carlina

Phytoestrogens are estrogenic compounds found in plants. These phytoestrogens are broadly defined to include isoflavones, coumestans and lignans. All three have naturally occurring plant estrogens that create a balancing effect on hormones, although both lignans and isoflavones are far more predominant in the human diet. Many people would be more familiar with the isoflavones found in soy, as lignans are relatively new on the scene.

Secoisolariciresinol diglycoside (SDG) is the plant lignan that is most notably found in flaxseed. It is classified as a phytoestrogen because it is a plant-derived, nonsteroid compound that is known for estrogen-like activity. The level of SDG in flaxseed can vary between 0.6 percent and 1.8 percent. SDG has both estrogenic and antioxidant activities. It is said that lignans can influence energy levels and sleep patterns, provide immune support, aid in digestion, and that they are potentially anti-viral, anti-fungal, anti-parasitic, and anti-carcinogenic.

Early research suggests lignans may protect against cancers, including breast cancer, prostate cancer and colon cancer. One of the breast cancer risks factors is described as excess exposure to the hormone estrogen. Observational studies have found that breast cancer patients and those with a high risk of breast cancer excrete less mammalian lignans than people with a lower risk of breast cancer. One study found that women with high enterolcatone levels in their blood (the end result of the conversion of lignans) had a lower risk of breast cancer.

The plant lignans found in flax are known to interfere with estrogen metabolism in animals and humans by mimicking estrogen, thus tricking the body into thinking estrogen is present so it stops overproducing it.

It is important to note that lignans must be complimented by the presence of 'good bacteria' in the intestinal tract and colon in order to effectively complete their conversion. Ingested plant lignans are converted to mammalian lignans by gut and colon bacteria. These mammalian lignans have two metabolic fates. Either they can be excreted directly in the feces, or after being absorbed by the gut they enter enterohepatic circulation, which means that they are partially reabsorbed, conjugated mainly with glucuronate and then excreted in urine and bile. The amount of lignans ingested and utilized can be detected in the urine (in the forms of enterolactone and enterodiol).

Although fibre content remains quite constant in flaxseeds and flaxseed powder this is not the case with lignan content. In one tablespoon of flaxseed you will find approximately 8 mg of lignans, where in the same amount of flax powder the lignan content can vary between 70 mg and 300 mg. If you are looking for a source of lignans, the powders are your best bet.

There is much more research needed on the subject of phytoestrogens and lignans, but preliminary studies do indicate positive effects of lignans in the human diet. For those of us who choose to be proactive about our health, the addition of flaxseed and flaxseed powders to our daily regime is a simple way to add a tasty wholefood supplement, complete with protein, essential fats, fibre and lignans. What could be simpler?