Lignans
Lignans are a group of chemical compounds found in plants. Lignans are one of the major classes of phytoestrogens, which are estrogen-like chemicals and also act as antioxidants. The other classes of phytoestrogens are the Isoflavones and coumestans.
Special Precautions of Lignans
The benefits of Lignans are
- Studies show that breast cancer is lower in countries where the intake of phytoestrogens is high...implying that these compounds may reduce breast cancer risk," says Dr. Velentzis. "Isoflavones and lignans are the most common phytoestrogens in the diet." Dr. Velentzis says your best way to fight breast cancer is to increase your lignan intake.
- Lignans are also good antioxidants scavenging free radicals that may play a role in some diseases.
Food sources
Lignans are found in many foods. And researchers at Oregon State University (OSU) offer some guidance on the best places to get them. They say the best source is often found in seeds. You can find it in rich quantities in pumpkin seeds, poppy, flaxseed and sunflower seeds.
The next best source is found in vegetables including broccoli, kale, cabbage and Brussels sprouts.
Or...if you prefer fruit...you can also get rich quantities in strawberries and apricots.
Flaxseed and Sesame Seeds contain higher levels of lignans than most other foods. The principal lignan precursor found in flaxseed is secoisolariciresinol diglucoside. Other sources of lignans include cereals (rye, wheat, oat and barley - rye being the richest source), soybeans, Cruciferous Vegetables such as broccoli and cabbage, and some fruits, particularly apricots and strawberries.
Secoisolariciresinol and matairesinol were the first plant lignans identified in foods. Pinoresinol and lariciresinol are more recently identified plant lignans that contribute substantially to the total dietary lignan intakes. Typically, Lariciresinol and pinoresinol contribute about 75% to the total lignan intake whereas secoisolariciresinol and matairesinol contribute only about 25%.This distribution may change as the contributions of syringaresinol and hydroxymatairesinol have not properly been quantified in foods.
Sources of lignans:
| Source | Amount per 100 g |
|---|---|
| Flaxseed | 300,000 µg (0.3 g) |
| Sesame seed | 29,000 µg (29 mg) |
| Brassica vegetables | 185 - 2321 µg |
| Grains | 7 - 764 µg |
| Red wine | 91 µg |
A recent study shows the complexity of mammalian lignan precursors in the diet. In the table below are a few examples of the 22 analyzed species and the 24 lignans identified in this study.
