WHAT ARE THE LIGNANS?
The lignans are a group of phytonutrients (plant based chemical compounds that have numerous health benefits but are not classed as essential nutrients). They are mainly found in seeds with flaxseeds often being the richest source. Although they are not classed as essential nutrients, early evidence suggests that they can prevent a wide range of nasty diseases (such as cancer and heart disease) and much more. In this article I will be taking a detailed look at the lignans and providing a full breakdown of their health benefits.
WHAT ARE THE DIFFERENT TYPES OF LIGNANS?
There are 2 main types of lignans; plant lignans and mammalian lignans. Plant lignans are the initial form of lignan that you eat and these are then converted into mammalian lignans inside your body. Plant lignans and mammalian lignans can be further broken down into the categories below:
1) PLANT LIGNANS:
– Lariciresinol.
– Matairesinol.
– Pinoresinol.
– Secoisolariciresinol Diglucoside (SDG).
2) MAMMALIAN LIGNANS:
– Enterodiol.
– Enterolactone.
WHAT IS THE HISTORY OF LIGNANS?
Awareness of lignans dates back to the 11th century where the roots of wild Chervil (which contains several lignans) were used as a cancer treatment. However, they were not discovered until relatively recently in 1956.
WHAT ARE THE HEALTH BENEFITS OF LIGNANS?
The lignans are powerful antioxidants which can protect your body’s cells from dangerous free radicals (harmful by-products that are released into your body’s cells during oxygen reactions). They are also potent phytoestrogens (substances that regulate estrogen levels in the body and can prevent cancer, prevent heart disease, prevent osteoporosis (reduced bone mineral density) and relieve the negative symptoms of menopause).
Provisional evidence suggests that the lignans may also have further health benefits in humans. However, since they were only discovered very recently more studies are required before these benefits can be confirmed. These provisional health benefits of lignans are highlighted in the list below:
– Possibly acting as an anti-inflammatory (a substance which prevents unnecessary inflammation in the body).
– Possibly increasing cardiovascular health (by protecting the heart from free radicals, reducing high blood pressure and lowering LDL cholesterol levels).
– Possibly preventing and treating various types of cancer (including breast cancer, colon cancer, lung cancer, ovarian cancer and prostate cancer).
– Possibly preventing atherosclerosis (a condition where hard plaques form in the artery walls and restrict the flow of blood which ultimately increases your heart disease risk).
– Possibly preventing diabetes.
– Possibly preventing hyperlipidaemia (an abnormally high concentration of fats or lipids in the blood).
– Possibly preventing male hair loss.
– Possibly preventing the accumulation of excess fats in the liver.
– Possibly preventing osteoporosis.
– Possibly reducing blood levels of LDL cholesterol (a type of cholesterol which can cause blockages in the arteries and increase your heart disease risk).
– Possibly reducing high blood pressure.
HOW MUCH LIGNANS DO YOU NEED?
The lignans are not classed as essential nutrients so no official recommended daily allowance (RDA) has been established. However, most sources suggest a daily dose of between 25 milligrams (mg) and 50mg.
WHICH FOODS CONTAIN LIGNANS?
Flaxseed is by far the richest source of lignans. However, some other plant based foods also contain high levels of these phytonutrients. The table below outlines some of the top lignan food sources:
| FOOD | MILLIGRAMS (MG) OF LIGNANS PER 100 GRAMS (G) |
| Apricots | 1.4 |
| Broccoli | 2.12 |
| Brussels Sprouts | 1.06 |
| Cabbage | 1.06 |
| Curly Kale | 2.82 |
| Flaxseeds | 301.59 |
| Sesame Seeds | 39.51 |
WHAT ARE THE SYMPTOMS OF CONSUMING TOO MUCH LIGNANS?
Currently there are no reported overdose symptoms associated with lignans consumption but pregnant women and people suffering from cancer should see their doctor before consuming these phytonutrients. Additionally, consuming extremely high levels of flaxseeds (the main source of lignans) can have a number of unpleasant side effects which include:
– Causing gastrointestinal (GI) blockages.
– Increasing the risk of bleeding for people with blood disorders.
WHAT ARE THE SYMPTOMS OF FAILING TO CONSUME ENOUGH LIGNANS?
The lignans are not classed as essential nutrients so no deficiency symptoms have been established.
LIGNANS SUMMARY
There is still a lot to learn about the lignans and their health benefits. However, they have great potential when it comes to human health. Flaxseed in particular is something that you should really consider adding to your diet. Not only is it a rich source of lignans but it also contains high levels of omega 3 fatty acids, dietary fibre, various vitamins and key minerals.
Sources:
Flaxseed (WebMD)
Lignans: chemical, biological and clinical properties (Google Books)
Lignans (Lignans.net)
List of Phytochemicals in Food (Wikipedia)
The Growing Science Of Lignans Health Benefits (NutraIngredients.com)