Flaxseed Fibre: A New Superfood?

• An analysis and nutritional investigation on flaxseed fibre

• Dr Laurence Eyres NZIFST

• Mike Eyres

• Flax, Linum usitatissimum, is an upright annual plant growing to 1.2 m (3 ft. 11 in) tall, with slender stems.

• The flowers are pure pale blue, 15–25 mm diameter, with five petals; they can also be bright red.

• 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

Agenda

• The low temperature extraction process: Contrast to traditional expelling.

• 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 with Chia.

• Practical applications in the food industry.• Applications in nutraceuticals and natural medicine.• Scientific literature review.

Introduction

• 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-edible purposes.

Nutritional food products from flax

Nutritional components

• Proteins• Alpha linolenic acid (ALA)• Dietary fibre• Mucilage• lignans

Compare whole flax, flax fibre and Chia

Whole Flaxseed Flaxseed meal(fibre) Chia ,salba flour

%m/m

Protein 22 34 21.2

Fibre(dietary) 30 37 34.5

Carbohydrate 2 2.4 37.5

Oil 43 14-16 31.4

Ash 2.8 4.6 4.6

Moisture 6.5 8.2 8

Gluten nd <3ppm <5ppm

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.

Lignans

• Total lignans around 650 mg/100g in defatted flax meal

Lignans

• 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 matairesinol (MATA).

• 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 saturates.

ALA

• 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 al.)

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 2004).

• A high ratio of omega-6/omega-3 is detrimental to health and may lead to the development of chronic diseases.

• 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 & Cleland, 2003).

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.

Dietary 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, 2011).

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

Page 18

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 cholesterol”

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

Cyanogenic glycosides • 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 (FSANZ, 2014).

• 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.

Cyanogenic glycosides

• 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 linseed (FSANZ).

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 compounds.

Food products utilising flax

• Kibbled cookies• Muesli bars• Wholegrain breads• Muffins• Protein snacks• Smoothies

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.