Flaxseed Fibre: A New Superfood?
• An analysis and
on flaxseed fibre
• Dr Laurence Eyres
• Mike Eyres
• Flax, Linum usitatissimum, is an upright annual plant growing to 1.2 m (3 ft. 11 in) tall, with
• The flowers are pure pale blue, 15–25 mm diameter, with five petals; they can also be bright
• The fruit is a round, dry capsule 5–9 mm diameter, containing several glossy brown
seeds shaped like an apple pip, 4–7 mm long.
• Referring to the plant itself, the word "flax" may refer to the unspun fibres of the flax plant.
Flaxseed Plant Structure
• The low temperature extraction process: Contrast to
• Compositional and nutritional information: Certified
analysis. Quality statistics. Deactivation of cyanogenic
glycosides and reduction in APC.
• Lignans, ALA, dietary fibre soluble and insoluble fibre.
Vitamins and minerals Amino acid profile. Comparison
• Practical applications in the food industry.
• Applications in nutraceuticals and natural medicine.
• Scientific literature review.
• Flaxseed meal or fibre is also known as
defatted flaxseed from the low temperature
expelling of the whole seed (linum
usitatissium L.) to produce flaxseed oil. It is
differentiated from the large scale high
temperature expelling of linseed, the oil from
which is generally used for industrial and non-
Flaxseed major constituents
• The health benefits of flax meal are attributed to
its alpha-linolenic acid (ALA), fibre and lignan
content. These active constituents may have
synergistic actions that account for flax being
referred to as a functional food or a super food.
That is to say there are health benefits gained by
consumption that are beyond those expected
based on its nutritional composition. The health
benefits of flax can be inferred by the study of the
health effects of these components in isolation.
Proteins of flax
• Albumins and globulins are the storage
proteins of flaxseed.
• The major amino acids are arginine,
phenylalanine and tyrosine, leucine and
methionine and cystine.
• The limiting amino acid is lysine being 60% of
that in soybean or canola.
• Total lignans around
650 mg/100g in
defatted flax meal
• The richest source of lignans is from flax.
• They are 2,3 dibenzyl butane structures.
• The two lignans found in humans are
enterolactone and enterodiol.
• They arise from the metabolism of the plant
lignans secoisolariciresinol (SECO) and
• They are weakly oestrogenic.
• They have been shown to have chemo
preventative properties and inhibit angiogenesis.
Lipids of flax
• The total lipids of Flaxseed grown in New Zealand
are of a superior quality re: ALA, and levels in the
range of 60 to 65% are not uncommon. 16% is
linoleic acid (LA) an omega 6 fatty acid, 18% is
oleic acid, 5% is stearic acid, and 5% is palmitic
acid, which provides an excellent n-6: n-3 fatty
acid ratio of approximately 0.3:1 with low
• The benefits of ALA are seen at intakes as low as
1g/day (National Heart Foundation of Australia,
2008). A recent review concluded that for every
1g per day increase in ALA consumption
corresponded to a 10% reduction in risk of CHD
death based on an analysis of 5 cohort studies
(Pan et al., 2012). Primary intervention studies
using ALA rich oils such as flax oil have shown
mixed results, so that at this time it is unclear if
ALA is the constituent with the effect or if it is
something else in ALA containing foods (Nestel et
ALA-alpha linolenic acid
An omega-3 fatty acid
• There is an optimal ratio of omega- 6 to omega-3
in the human diet of around 4-5:1 (Simopolous
• A high ratio of omega-6/omega-3 is detrimental
to health and may lead to the development of
• Improving the dietary ratio by increasing the
omega-3 fatty acids is essential for brain function
and for the management of cardiovascular
disease, arthritis and cancer (Simopoulos &
Recent Heart Foundation Review
• A recent review by Nestel et.al. On behalf of the
National Heart Foundation of Australia found no data
to support changing the 2008 position statement
recommending 2g of ALA per day in secondary
prevention of coronary heart disease (Nestel et.al,
2015). The authors identified 12 sources of clinical
information concerning the effects of ALA on
cardiovascular disease. A summary of their conclusions
was that each 1g per day of ALA was associated with a
10% lowering of the risk of CHD.
• 2 g of ALA is found in 30 g Flaxseed fibre.
• Flaxseed meal is high in fibre, a significant
amount of which is soluble (20%) in the form
of gums and mucilages. In addition to
accounting for the laxative effect of flax meal,
soluble fibre is known to have potent
cholesterol lowering qualities therefore
reducing a major risk factor for cardiovascular
disease (Singh, Mridula, Rehal, & Barnwal,
Health benefits of Fibre
• The EPIC-InterAct study showed that a high
intake of total fibre compared with a low
intake was associated with an 18% lower risk
of incident type 2 diabetes when adjusted for
lifestyle and dietary factors.
• Cohorts: whole grain users (48-80
g/day vs ”low users”)
– Relative risk of T2D ↓ by 28 %
– Relative risk of CVD ↓ by 21 %
– Weigh 0.4 kilos less
• RCT:s (21 trials): Whole grain diet
vs control diet
– 0.72 mmol ↓ LDL
– 0.93 mmol ↓ fP-Glc
Systematic review of prospective cohorts and RCTs:
whole grains associated with reduced risk of T2D,
weight gain and CVD
Ye E et al. Greater whole-grain intake is associated with lower risk of type 2 diabetes,
cardiovascular disease, and weight gain. J Nutr. 2012 Jul;142(7):1304-13.
Flax and Cholesterol
• In Canada there is now an approved health claim for the use of flax
as an intervention to lower serum cholesterol.
From Health Canada:
• 16 g (2 tablespoons) of ground flaxseed supplies 40% of the daily
amount shown to help lower cholesterol.
• The "daily amount" referred to in the primary statement is 40 g of
ground whole flaxseed. This amount is based on the evidence
available concerning the amount of ground whole flaxseed shown
to help reduce cholesterol. In this statement, the percentage of the
daily amount of ground whole flaxseed provided in one serving
should be rounded to the nearest multiple of 5%.
• The following additional statements could be placed adjacent to the
primary statement, in letters up to twice the size and prominence
of those in the primary statement:
“Ground (whole) flaxseed helps reduce/lower
Flax and Blood Pressure
• A recent systematic review and meta analysis
found that flax consistently lowers blood
pressure, the effect was greater when flaxseed
was consumed for at least 12 weeks.
Possible anti-nutrient factors in flax
• There are approximately 25 known cyanogenic
glycosides and these are generally found in the edible
parts of plants, including almonds, stone fruit, cassava,
bamboo shoots, linseed/flaxseed and lima beans
• The US FDA had reservations about flax before 1982,
then quoted that uncooked foods such as breakfast
cereals with 10-12% FLAX PRESENTED NO LIKELIHOOD
of any more exposure to HCN than other foods such as
chickpeas, lima beans, cassava, cashews or almonds.
• For bread containing linseed, although the
estimated acute dietary exposures resulted in
potential exceedances of the ARfD for all
population groups assessed, current
exposures are not considered to represent a
health and safety risk due to the absence of
any clinical reports of poisonings or detectable
levels of cyanide in the blood of human
volunteers following consumption of ground
Utilisation of flax in foods
• The mild heat treatment in processing the
flaxseed may result in a minor reduction of
cyanogenic material but the hot baking process
used for many foods will inactivate the enzyme
necessary for the activation. Based on the
previous considerations, the consumption of
flaxseed is recommended in the form of flour,
after thermal treatment, because not only are the
concentrations of compounds with adverse
effects eliminated or reduced, processing of the
seed increases bioavailability of the bioactive
Samples for evaluation
• This review was sponsored by Midlands Seed Ltd
(Midlands), Ashburton, Canterbury, New
Zealand. The company was established in 1990,
to support and encourage the production and
export of arable crops from New Zealand. Since
then, the company has grown rapidly to become
one of New Zealand’s top producers and
marketers of vegetable and herbage seeds, dried
peas and oilseeds, as well as cereal grains.
Flaxseed and its products are a mainstay of
Midlands Arable Foods product range.