Flaxseed and its lignans - in particular secoisolariciresinol diglucoside (SDG) - have been studied for their beneficial effects on a number of health conditions, including hair loss and benign prostatic hyperplasia, both of which affect men. Further investigations ongoing, both by ingredients companies and research institutes.
For this reason, Acatris said it is "important to know if the lignans in commercially available flax ingredients are bioavailable".
The study was conducted at Kanda Ishin Clinic in Tokyo, Japan. Although it was only a pilot study involving nine men, five of whom stuck with it through the whole six months, from their findings the researchers concluded that lignans from LinumLife are absorbed, and do increase serum levels of enterolactone (ENL) and enteroldiol (END).
SDG is said to be converted by microflora in the gut into secoisolariciresinol, which is then further metabolised into ENL and END. These two mammalian lignans are then absorbed from the gut and transported to the liver where they undergo further reactions before entering circulation.
The men in the study received a daily dose of 1 gram of LimumLife, equivalent to 40mg of SDG. Their serum END and ENL levels were measured at baseline, three months and six months.
At baseline, their average levels were 115nmol/L. At three months they had increased 25 per cent to 145 nmol/L, and at six months were around 136 nmol/L.
The researchers said that the results indicate a plateau is reached in blood END and ENL levels at the dose applied.
There are some limitations to the study, most notably that it involved so few participants which meant that the standard deviation in the results was large.
What is more, flax lignans are most commonly marketed to people following a Western diet, in which lignans are often missing or limited because of modern processing methods.
A typical Western individual would have lignan levels of between 8 and 30nmol/L, thus the participants' levels were already far in excess of this.
The researcher say this factor may be explained by the fact that the study was conducted in Japan, and the Japanese typically consume more lignan-rich foods as part of their normal diet.
Nonetheless, Acatris says that as research is concluded on flax lignans, it "will continue to feed a healthy marketplace appetite".
Mintel's Global New Products Database lists 35 entries of supplements mentioning lignans since 1998 (some consisting of multiple stock keeping units), 29 of which were in the United States and two in Canada. The only listed European entries are three in the UK and one in each of Finland and Sweden. Three entries are for launches in the UK.
Indeed, flax lignans dominate the ingredients lists of the entries in Mintel's database; the vast majority of lignans in the supplements were either SDG extracted from flaxseeds or from flax oil used in the formulation; sesame and linseed put in two appearances each as lignan sources.
The preponderance of flax on the market is no surprise since newcomer Linnea only launched its spruce pine bark derived HMRLignan to the industry at SupplySide West last autumn. The company is progressing with a research programme that aims to establish the health benefits of HMR (7-hydroxymatairesinol) independently of that conducted using SDG.