By using certain human intestinal bacteria to break down flaxseed husks, food supplements can be created which could temper the effects of menopause. This was the conclusion of the Wageningen food technologist ir. Karin Struijs in her PhD thesis.
During the past six years, Struijs has been conducting fundamental research into the structure of flax lignans and their conversion in the human body. Epidemiological research has shown that flaxseed, also known as linseed, has health-promoting effects. Besides the high fibre content and beneficial fatty acid composition of flaxseed, the lignans take a special role. They are currently the subject of much interest as a supplement for women in menopause.
This is because lignans, which are also present in bread and coffee, are broken down in the intestines to enterodiol and enterolactone. These act like mild artificial hormones which probably counteract osteoporosis, prevent hot flashes and perhaps even reduce the risk of breast cancer.
In her research, Struijs used the lignan-rich husk of the flaxseed, a waste product from linseed oil production, which is now used primarily for animal feed. First of all, she studied the form in which the lignans are present in flaxseed. Together with other components, they turned out to be formed of large, extremely complex molecules which the human body is unable to absorb in this state. It is only in the intestines that this large molecule is converted by a number of special bacteria species into a useful, bioactive form such as enterodiol.
However, the release of the bioactive form depends on the composition of the intestinal flora. This composition can differ between individuals, which makes the effectiveness of a flax supplement uncertain. Therefore, Struijs 'trained' the intestinal bacteria to make this conversion step in the laboratory. In this way, it became possible to use the active substance directly in a nutritional supplement. ‘This is more expensive, however’, explains Struijs. ‘And there is another qualification. It is not yet certain whether the lignans can pass through the stomach in this form.’
Karin Struijs defended her doctoral thesis on 17 November. Her PhD supervisor was Prof. Harry Gruppen, Professor of Food Chemistry at Wageningen University.