Linum usitatissimum / Lijnzaad

Monografie uit het cursusboek van de herboristen opleiding 'Dodonaeus'

Dat bruine, platte zaadje uit de vlasplant Linum usitatisimum is al eeuwenlang in gebruik als voedselplant. Toch ontdekken we nog steeds nieuwe medicinale werkingen van dat onooglijk zaad. Een overzicht.
http://mens-en-gezondheid.infonu.nl/gezonde-voeding/39605-lijnzaad-voedsel-en-medicijn.html

Algemene en Botanische Informatie 
Familie: Linaceae - Vlasfamilie. 
Naam: Lin (Fr.), Lein (D.), Line (E.). 
Soorten: 
  • Linum catharticum L. - Geelhartje, 
  • Linum tenuifolium L. - Smalbladige vlas, 
  • L. bienne MILLER - Tweejarige vlas, 
  • L. angustifolium HUDSON - Waarschijnlijk de moeder plant van L. usitatisissum 
Variëteiten: Van Linum usit.:
- Var. crepitans SCHÜBLER met openspringende vruchten, grotere zaden (vooral in warme streken voor zaadteelt). 
- Var. vulgare SCHÜBLER met niet-openspringende vruchten en kleinere zaden, vooral geteeld voor de vezels (vooral in koudere streken). 
Andere variëteiten:
- L. usitatissimum subsp. eurasiaticum var. Intermedia Sorte Midas LN 33, Sorte Ceres LN 34, 
- L. ustatissimum subsp. eurasiaticum var. sublongata, Sorte Hella LN 30 (firma Fink). 

Materia Medica, gebruikte delen van de plant

Lini semen, Het zaad van L. usitatissimum L. vooral var. crepitans. 
Oogst: Volledig rijpe zaden tijdens de herfst, de plant en de ronde zaaddozen zijn dan bruin, (gehalte aan slijmstof en onver zadigde vetzuren is het hoogst) 
Bewaren: Buiten invloed van het licht, in goed sluitende vaten, beschermen tegen insecten (volgens N. F. VI is de bewaartijd maximum 1 jaar) 
Kwaliteit: Lijnzaad mag niet meer dan 3 % vreemde zaden bevatten. (B. F. IV.) 
Verontreiniging met o.a. Kroddezaad, Mosterd zaad e.a. Cruciferae 
Het zwelgetal moet volgens DAB minstens 4 zijn (5 is beter). 
Beschrijving: Helderbruin, glanzend en glad, eivormig met spitse top en afgeronde voet, afgeplat. Smaak: zoet en slijmerig. 

Lini oleum, De (koud) geperste olie uit de zaden. 
Lini seminis pulvis 
Lijnzaadmeel: liefst direct na het malen te gebruiken. Kwaliteit: Mag niet ranzig ruiken en geen mijten bevatten. (F. Helv. V.) 

Beschrijving lijnzaad in EUROPEAN PHARMACOPOEIA 5.0: The seeds have a flattened, elongated ovoid shape and are 4 mm to 6 mm long, 2 mm to 3 mm wide and 1.5 mm to 2 mm thick; one end is rounded and the other end forms an oblique point near which the hilum appears as a slight depression. The testa is dark reddish-brown, smooth and glossy but when viewed with a lens the surface is seen to be minutely pitted. The interior of the testa has a narrow, whitish endosperm and an embryo composed of 2 large, flattened, yellowish and oily cotyledons; the radicle points towards the hilum.

Beschrijving lijnzaadolie
Virgin oil obtained by cold expression from ripe seeds of Linum usitatissimum L. A suitable antioxidant may be added.
Appearance: clear, yellow or brownish-yellow liquid, on exposure to air turning dark and gradually thickening. Cooled, it becomes a soft mass at about −20 °C.
Solubility : very slightly soluble in alcohol, miscible with light petroleum.
Relative density: about 0.931.
Refractive index: about 1.480.

Samenstelling, inhoudsstoffen van Linum semen
** Slijmstoffen 10 %. Bij hydrolise ontstaan o.a. galacturonzuur, galactose, sylose, enz. 
** Lipiden 30-40 % met o.a.: linoleenzuur 35-50 % en linolzuur (vit. F), omega-3-vetzuren
* Eiwitten 20-25 %. 
* Glucosiden: vooral cyanogene heterosiden (HCN) 
* Pectine 6 %. 
* Mineralen 3 %: vooral K, Ca en Mg 
* Water 10 % 
* Linatin = vit B6-antagonist 
Nota: Hoe rijper het zaad, hoe meer olie en hoe meer onverzadigde vetzuren. 

The medical properties of flax are primarily associated with the seed. Flaxseed is composed of multiple chemical constituents, the mechanisms of which are slowly being analyzed. Studies have attributed different medicinal properties to unsaturated fatty acids (mainly ALA and linoleic acid), lignans (predominantly secoisolarciresinol diglucoside), and nonstarch polysaccharides ( gum, fiber). Flax produces a seed that contains 38% to 45% oil. Also known as linseed oil, it is obtained by crushing and compressing the seeds. The oil is composed of approximately 70% polyunsaturated fatty acids, including linolenic, linoleic, and oleic acids ; approximately 18% monounsaturated fatty acids; and approximately 9% saturated fatty acids. Flaxseed or linseed oils are among the best natural sources of ALA, an omega-3 fatty acid. Linoleic acid, a rich source of omega-6 fatty acid, and ALA are critical for the structural integrity of cell membranes. ALA is a precursor to the longer and more unsaturated omega-3 fatty acids EPA and DHA; however, only a modest amount of ALA appears to be converted to these longer chain fatty acids.

Whole or ground flaxseed is a rich source of lignans, including secoisolariciresinol and matairesinol. These lignans are believed to exert antioxidant and phytoestrogenic effects. They are converted by bacteria in the colon to the active metabolites enterodiol and enterolactone. These metabolites are reported to have greater antioxidant activity than the parent lignan secoisolarciresinol diglucoside 12 and also exert either a weak estrogenic or an antiestrogenic effect, depending on the biological levels of estradiol.

Whole or ground flaxseed is a source of a soluble fiber mucilage that is also found in other members of the Linum genus. This gum-like material contains polysaccharides containing D-xylose, L-rhamnose, L-galactose, arabinose, D-galacturonic and mannuronic acids, fucose, and glucuronic acid. Flaxseed may also contain phenylpropanoids (eg, p -coumaric, o -coumaric, linusitamarin). The nutrient composition of the 3 forms of flaxseed differ. Flaxseed oil differs from whole and ground flaxseed because it is devoid of fiber and lignans. 8 Flax leaves and seed chaff contain the cyanogenic glycosides linamarin, linustatin, and neolinustatin, which can increase blood levels and urinary excretion of the thiocyanate in humans consuming raw flax or flaxseed and cause toxicity in grazing animals as cyanide is released from these compounds when the tissues are crushed. These glycosides have not been detected after flaxseed has been baked.

Farmacologie, algemene fysiologische werking 
** Laxativum en purgativum. 
- Mechanisch laxeermiddel, door het opzwellen van de zaden in de darm wordt de inhoud vergroot 
- Gemalen of geplet zaad, de olie komt vrij en heeft een smerend effect 
- Ontgeurt de faeces 
* Ontstekingswerend (slijmstoffen) vooral voor: 
- slijmvliezen van de darm en urinewegen, 
- huid (verzachtend) = emolliens. 
* Bloedvatbeschermend (vit. F, vetzuren) 
Contra-ind.: Niet geschikt voor personen met schildklierstoornis. Goitrogeen effect. (?) 
Toxiciteit1: 
- Zonder gevaar ondanks de aanwezigheid van blauwzuurverbindingen (HCN), deze worden o.a. geneutraliseerd door het zuur van de maag. 
- De harde schil kan de darmwand prikkelen, wordt weer tegengegaan door de slijmstoffen

Indicaties, medicinaal gebruik
Darmen (slijmstoffen)
** Constipatie, vooral chronische, om v/d antrachinonhoudende (Senna, Aloe, Vuilboom) drogerijen af te geraken 

Huid en Uitwendig 
** Zweren, abcessen (zie ook Fenegriek) 
* Brandwonden en zonnebrand (Lijnzaademulsie) 
* Eczeem droog (inwendig en uitwendig Lijnolie) 
* Huidirritatie (zie ook Echte Kamille en andere slijmstofplanten) 
* Restplekken psoriasis + ruwe schurftige huid 

Slijmvliezen 
** Urineweginfecties o.a. cystitis. Zie kr. v/d urinewe gen o.a. Solidago. 
* Maag-darmontsteking (gastritis). Zie ook Matricaria, Glycyrrhiza...
        R./   Lini sem. 4 
                Malvae fl. 5 
                Glycyrrhizae rad. 4         Ber.: dec. 3' + 60' mac. 
* Buikpijn, leverzwelling. 
                Warm compres lijnzaad zakjes 

Voedingssupplement voor bloedvaten, kankerpreventie en prostaathypertrofie: zaad in muesli en brood, liefst gebroken.
Based on human, placebo controlled clinical trials, taking 50g of flaxseed/day in four flax muffins brings a 9.8% reduction in LDL 
cholesterol and 19.8% reduction in Lp(a) within three weeks. For this purpose, flaxseeds must be ground up first, because if they are eaten whole, they will not be digested and will pass right through the digestive tract. http://www.florahealth.com/Flaxseed.htm

Receptuur en bereidingswijzen 
  • Maceraat: Lini semen 1 eetlepel = ± 15 g. Licht gekneusd zaad of heel zaad gebruiken, 1-2 eetl. 3 x daags met water; laxerend na 2-3 dagen
  • Emulsie: Lijnzaademulsie: lijnolie + kalkwater (gelijke delen). 
  • Pulves: R./ Lini sem. pulv. vers grof gemalen lijnzaad. Gebruik.: warme compres op gaasverband.  Indicatie: verzachtend en bevordert rijping abcessen (emolliens) 
Nota: Oud, ranzig lijnzaadmeel kan irritatie veroorzaken. 

Species ad cataplasmata (mengsel)
  • Matricaria cham.    20 
  • Althaea fol. pulv.   20 
  • Malvae fol. pulv.    20 
  • Lini sem. pulv.       20     Bereiding.: maceraat (koud aftreksel) 30' daarna even opkoken tot brei. 
Geschiedenis En Wetenschappelijk Onderzoek 

- 650 voor Chr.: Reeds als genots- en voedingsmiddel bekend. 
- Hyppokrates, Dioscorides, Plinius, Galenus e.a.: Vermelden lijnzaad als medicijn.
- Bock (1565), Matthiolus (1611): in kruidenboeken.

Wetenschappelijk onderzoek
  • Kurth W.: Therapeutische Wirksamkeit, Verträglichkeit und Akzeptalität von L. usit. Receptür in der Praxis - Der Kassenarzt 16/3546 - 1976. 
  • Jens R. e.a.: Ergebnisse einer Praxisstudie mit einer Leinsamen. Kombi na tion zur Behebung der chronischen Obstipation bei 1214 Patiën ten. Positief resultaat 76,3 %. Der Prakti sche Arzt 35/80 - 1981. 
  • Zeitschrift f. Phytoth. 7/113-117 - 1986  "Zur Wirksamkeit und Toxicologie von Semen Lini
  • Pan A, Yu D, Demark-Wahnefried W. Meta-analysis of the effects of flaxseed interventions on blood lipids. American Journal of Clinical Nutrition. 2009;90(2):288–297.
  • Lijnzaad verhoogt aanmaak testosteron. Toxicologen van de FDA hebben ontdekt dat een dieet met vlaszaad of vlasmeel de hoeveelheid testosteron en LH verhoogt. Hoe dat gebeurt is niet uit het onderzoek af te leiden. De wetenschappers wilden weten of vlaszaad, dat in steeds meer supplementen wordt verwerkt, de mannelijke voorplanting ontregelt. 
    De onderzoekers gaven zwangere ratten voer dat voor 20 procent of 40 procent uit vlaszaad bestond, of voor 13 procent of 26 procent uit vlasmeel. Nadat de dieren waren bevallen, gaven de wetenschappers de jongen zeventig dagen lang hetzelfde dieet. De bevindingen hebben betrekking op die jongen. 
    Vlas is niet gevaarlijk, ontdekten de onderzoekers. De kwaliteit en aanmaak van de zaadcellen, het gewicht van de zaadballen en de zaadleiders en de testosteronconcentraties in de geslachtsorganen veranderde niet. 
    Wel steeg in de beide vlaszaadgroepen de aanmaak van het stuurhormoon LH, dat de zaadballen aanzet om meer testosteron aan te maken. In de groep waarvan het voer voor 26 procent uit vlasmeel bestond, stegen zowel de LH als het testosteron. Door het malen van het zaad wordt op opneembaarheid van de actieve stoffen waarschijnlijk groter. Daarnaast verminderde het gewicht van de prostaat in alle groepen. 
    De resultaten lijken te wijzen op de aanwezigheid van pseudo-hormonen, misschien wel pseudo-androgenen, in vlas. 

    Sprando RL, Collins TF, Black TN, Olejnik N, Rorie JI, Scott M, Wiesenfeld P, Babu US, O'Donnell M. The effect of maternal exposure to flaxseed on spermatogenesis in F(1) generation rats. Food and Chemical Toxicology, april 2000, 38(4), blz. 325-334. 

Samenvatting Flaxseed.
Flaxseed and flaxseed oil contain various essential fatty acids but are particularly rich in alpha linolenic acid (ALA), an omega-3 fatty acid and precursor to the longer and less saturated omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Flaxseed (but not flaxseed oil) also contains high fiber that may have health benefits similar to other high-fiber products and phytoestrogens that may exert weak estrogenic or antiestrogenic effects depending on biological levels of estradiol. Historically, linseed oil, derived from flaxseed, has been used as a topical demulcent and emollient, as a laxative, and as a treatment for coughs, colds, and urinary tract infections. More recently, flaxseed has been investigated for protection against atherosclerotic cardiovascular disease, including reduction of serum cholesterol, platelet aggregation, and inflammatory markers; chemoprotection against some cancers; improvement of menopausal symptoms; improvement of attention deficit hyperactivity disorder (ADHD) symptoms; and renoprotection in patients with systemic lupus erythematosus (SLE).

Links internet



Lignanen in lijnzaad

Lignanen zijn fyto-oestrogenen die door raffinageprocessen veelal verwijderd worden uit voedingsmiddelen. Uit onderzoek blijkt dat lignanen o.a. prostaatvergroting helpen te voorkomen.
Lignanen zijn fyto-oestrogenen in de vorm van difenolen (secoisolariciresinol diglycoside (SDG), matairesinol, pinoresinol, isolariciresinol), die voorkomen in zaden, granen, peulvruchten, groenten en thee. Door raffinageprocessen worden lignanen veelal verwijderd uit voedingsmiddelen. De hoogste concentratie lignanen is aanwezig in lijnzaad(vlies). Lignanen hebben een gunstige invloed op de hormoonhuishouding en hebben bovendien een krachtige antioxidantwerking. Uit onderzoek blijkt dat lignanen o.a. prostaatvergroting helpen te voorkomen.

Lignanen beïnvloeden de stofwisseling van (geslachts)hormonen. Er zijn aanwijzingen dat lignanen kanker en uitzaaiing van kanker helpen voorkomen. Lignanen zijn bovendien krachtige antioxidanten en ontstekingsremmers, ze verlagen de cholesterolspiegel (totaal- en LDL-cholesterol) en verbeteren de glucosestofwisseling door het verhogen van de insulinegevoeligheid van weefsels. Lignanen gaan atherosclerose , overgewicht en metabool syndroom tegen en zijn vermoedelijk een belangrijk wapen in de strijd tegen diabetes, hart- en vaatziekten en chronische nierziekten. In proefdierstudies is aangetoond dat lignanen beschermen tegen het ontstaan van diabetes. Ook de veelvoorkomende kaalheid bij mannen (androgene alopecia ) kan wellicht worden voorkomen of beperkt door ruime consumptie van lignanen. Kaalheid wordt evenals goedaardige prostaatvergroting toegeschreven aan een (lokaal) verhoogde vorming en/of activiteit van dihydrotestosteron, mogelijk mede door een lagere bloedspiegel van het testosteronbindende eiwit SHBG. Daarnaast speelt erfelijke aanleg een belangrijke rol. Tien kalende mannen (gemiddeld 45 jaar) namen zes maanden lang extra lignanen in (250 mg Linumlife® met 50 mg lignanen). Na afloop van de (ongepubliceerde) studie meldden acht mannen een milde verbetering van de haarconditie met minder haaruitval, één man zag een sterke verbetering en één man geen resultaat. De hoofdhuid was bij zeker de helft van de mannen minder droog. De beste resultaten met het lijnzaadextract werden gezien bij de mannen bij wie de kaalheid het verst was voortgeschreden.

Prasad K. Reduction of serum cholesterol and hypercholesterolemic atherosclerosis in rabbits by secoisolariciresinol diglucoside isolated from flaxseed. Circulation 1999;99:1355–62.
Prasad K. Hydroxyl radical-scavenging property of secoisolariciresinol diglucoside (SDG) isolated from flax-seed. Mol Cell Biochem 1997;168:117–23.
Prasad K. Antioxidant activity of secoisolariciresinol diglucoside-derived metabolites, secoisolariciresinol, enterodiol, and enterolactone. Int J Angiol 2000;9:220–5.
Prasad K. Hypocholesterolemic and antiatherosclerotic effect of flax lignan complex isolated from flaxseed. Atherosclerosis. 2005;179(2):269-75.Acatris. Pilot study suggests flax lignans help with hair loss. 2005-04-28. www.npicenter.com.



Journal of Natural Medicines January 2013, Volume 67, Issue 1, pp 222-227. The antidepressant effect of secoisolariciresinol, a lignan-type phytoestrogen constituent of flaxseed, on ovariectomized mice. Ying-Feng Wang, Zhi-Kun Xu, Dong-Hui Yang, Hai-Yan Yao, Bao-Shan Ku, Xiao-Qing Ma, Cheng-Zhi Wang, Shu-Lin Liu, Shao-Qing Cai
Secoisolariciresinol (SECO) is a natural lignan-type phytoestrogen constituent mainly found in flaxseed. It can be metabolized in vivo to mammalian lignans of enterodiol and enterolactone, which have been proven to be effective in relieving menopausal syndrome. Depression is one of the most common symptoms of menopausal syndrome, and is currently treated with estrogen replacement and antidepressant therapy. However, due to the serious side-effects of such agents, there are urgent needs for safer and more tolerable treatments. In this paper, using two classical depression models, the forced swimming test and the tail suspension test, we report the antidepressant effect of SECO on ovariectomized (OVX) mice by intragastric administration for 14 consecutive days at doses of 5, 10 and 20 mg/kg. The results showed that SECO (10 mg/kg) treatment could significantly reduce the duration of immobility of OVX mice in these two models compared with the control group (OVX mice + vehicle), which was similar to the positive control imipramine. In addition, SECO treatment could substantially increase brain monoamine (norepinephrine and dopamine) levels in OVX mice. The present studies showed that SECO can reverse depressive-like behavior and exhibit monoamine-enhancing effects.



POTENTIAL DISEASE TREATMENTS WITH FLAXSEED PHYTOCHEMICALS

Flaxseed's nutraceutical effects are believed to be caused by several factors. First, its oil contains high levels (53 percent) of a-linolenic acid (ALA), an essential fatty acid. Second, flaxseed fiber contains high levels of a lignan called secoisolariciresinol diglucoside (SDG). Finally, the gums and mucilage present in the flaxseed may contribute beneficial effects. These factors and their dietary implications for treating cancer, systemic lupus erythematosus (SLE), hyperlipidemia [high cholesterol], and perhaps malaria and rheumatoid arthritis (RA) are discussed in the following sections.

HISTORICAL BACKGROUND FOR SDG AND CANCER PREVENTION

Nutritional research has indicated a relationship between diet and chronic diseases such as cancer.(8-11) It is believed certain phytochemicals in fruits, grains, and nuts may underlie their ability to prevent cancer.(12) The phytochemicals in cereal grains are particularly interesting since there is a positive correlation between higher cancer rates (colon, rectal, and mammary) and the consumption of large amounts of fat and red meats in humans and test animals.(13) This correlation is reversed when diets contain large amounts of cereals. Cancer rates are also lower in countries where diets are vegetarian or semivegetarian.(14-17)

It is known that the benefits of low-fat, low-red-meat diets are not due to fiber alone but may also be due to a class of phytochemicals called lignans. Lignans have antitumor, antimitotic, antiviral, and enzyme inhibiting biological activities. Ayers and Loike(18) and MacRae and Towers(19) have thoroughly reviewed the medicinal uses of lignans. Before 1980, lignans were believed to exist only in higher plants. Then Setchell(20,21)and Stitch(22) discovered the first mammalian lignans (enterodiol and enterolactone), whose structures are closely related to the plant lignan, secoisolariciresinol. For more information on the serendipitous discovery of the mammalian lignans see Setchell.(23) Research by Axelson suggested(24) and Borriello proved(25) that secoisolariciresinol was converted by colonic bacteria within the animal's gut. Their research, coupled with the fact that mammalian lignan excretions are low in women with breast cancer but high in healthy women with no breast can cer history, intrigued many cancer researchers who hypothesized that the mammalian lignans were altering the human female hormone cycle.(26)

One research area was flaxseed since it contains more (between 75 and 800 times) SDG when compared with other food sources. For example, whole flaxseed contains about 527 micrograms SDG/gram flaxseed while the average concentration for 27 fruits is only 0.84 micrograms SDG/gram of fruit. These values were determined by Thompson et al.(27) in a study on the mammalian lignan content of 68 common food sources, using an in vitro bioassay, and verified by Hams and Haggerty(28) who developed an instrumental assay for SDG in defatted flaxseed flour. For an excellent review on the ability of lignans in whole grains to interact in sex hormone metabolism and how this interaction may prevent or modulate breast cancer and other diseases that are hormone related, see Thompson et al.(29)
Research efforts on the medicinal uses of flaxseed and its oil to treat and/or prevent various disease states is underway in laboratories worldwide. Since the number of papers on medicinal uses of flaxseed is quite voluminous and this paper is not intended to be a comprehensive review of all the potential medicinal benefits of flax, only selected and recently published information will be discussed.

EXPERIMENTAL CANCER RESEARCH WITH FLAXSEED FLOUR AND PURE SDG

The potential for preventing various cancers with flaxseed and pure SDG in the diet using animal models is revealed in the following examples. In 1992, Serraino and Thompson reported the results of three studies concerning the effects of flaxseed addition to the diets of test animals. In the first study on early risk markers for mammary carcinogenesis in high-fat diets(30) they used 5 percent and 10 percent flax flour supplementation. They found mammary tissue reductions in epithelial cells (39-55 percent) and nuclear aberrations (59-66 percent) with optimum reductions in the 5 percent diet. In their next study(31) on rats fed a high-fat diet mixed with 5 percent flax flour after injecting 7,12-dimethylbenz(a) anthracene (DMBA), a known carcinogen, they found a 67 percent reduction in the size of the mammary tumors produced. The decrease was more significant when the 5 percent flax flour diet was maintained throughout the study. The authors observed in both studies that the prot ective effects may be due to flaxseed because of an increase in urinary mammalian lignans; therefore, clarification of the lignans' role was required. In the last flaxseed feeding study a different tumor model and carcinogen was used. Azoxymethane, single injection, produced a 50 percent reduction in colon cancer for rats fed on 5 percent and 10 percent diets. Tumor reductions were not linear, based on the amount of flax flour consumed; however, this study did suggest that flaxseed consumption may reduce colon cancer risk.(32)
In the previous studies,(30-32) the ability of mammalian lignans to decrease cancer proliferation was deemed positive but their true effect was unclear. In a new study designed by Thompson et al.,(33) purified SDG was tested for its ability to inhibit mammary tumorigenesis caused by DMBA. Their study showed for the first time that SDG has an antitumor effect when provided at an early promotion stage of tumor formation and may contribute to the health benefits of high-fiber foods.

EFFECTS OF FLAXSEED ON LUPUS

Systemic lupus erythematosus (SLE or lupus) is considered a prototype autoimmune disease that primarily affects young women between the ages of 15 to 35.(34) In the early phase of SLE, patients suffer from inflamed blood vessels throughout their bodies while the later phases are characterized by kidney failure and cardiovascular complications (i.e., atherosclerosis, strokes). Immunosuppressive agents (i.e., steroids) can be used to treat SLE, but there are other risks with the selection of this modality.(35) Clark and co-workers explored a nutritional approach to treat the initial phases of SLE. They found that omega-3 fatty acid supplementation helped reduce inflammation.(36) Other medical teams examined methods for mitigating the later phase complications using test animal models. They learned that the platelet activating factor (PAF) played a major role in causing these problems; however, when the PAF receptors were blocked, complications decreased.(37-41)


Based on these facts, Clark and co-workers decided to explore the use of flaxseed as a nutritional treatment for both early and late phase SLE complications. They based their hypothesis on the previously known facts that flaxseed contains high concentrations of omega-3 fatty acids and is also a rich source of lignans, which are potent PAF antagonists.(27,42)

Their short-term study revealed diets containing 30 grams/day flaxseed were well tolerated by patients with SLE nephritis, exerted significant effects on kidney function, and lowered plasma lipids (particularly LDL cholesterol by 11 percent). Based on this study, the authors proposed further long-term studies.(38)

FLAXSEED AND CHRONIC RENAL TRANSPLANT REJECTION

Flaxseed has also been investigated for its potential to prevent renal transplant rejection (RTR) through dietetic means.(44,45) RTR damages both the immune and cardiovascular systems by affecting the heart and blood vessels, bringing about detrimental blood pressure changes. Diet studies on rats (Fisher 344 rats and Lewis rats) were made using a regular rat diet and a diet containing 15 percent flaxseed that contained the same amount of calories as the regular diet. The research team observed beneficial effects with this diet without using immunosuppressive drugs. The results were encouraging and warrant further investigation.

HIGH CHOLESTEROL (HYPERLIPIDEMIA)

High serum cholesterol, (particularly in low density lipids (LDL), is considered a significant risk factor for coronary heart disease. Several drug treatments are available for reducing cholesterol; however, when possible, it is better to control its level through diet. Flaxseed has been reported to lower serum cholesterol in both normolipidemic(43,44) and hyperlipidemic(45,46) subjects. Since flaxseed contains large amounts of mucilage (soluble fiber), a randomized, crossover feeding study was performed with human subjects by Cunnane and co-workers(44) using muffins prepared from defatted flaxseed flour. The control (no flaxseed) and the flaxseed muffins contained equal nutrients. During the study, no change was observed in the high density lipoprotein (HDL) [high levels of HDL are desirable because HDL removes cholesterol from the peripheral tissues and artery walls and delivers it to the liver for disposal] and triglycerides. However, plasma total cholesterol was reduced 6 percent and the LDL was reduced nine percent. This lowering occurred only while the flaxseed muffins were part of the diet. The results of this rigidly controlled study led the authors to conclude that the soluble gum (mucilage) was most likely responsible. They could not conclude, however, that flax lignans were not involved. This ambiguity between the lowering of blood lipids when flax is part of the diet has been noted before.(47) They also concluded that traditional flaxseed lowers cholesterol under well-controlled conditions and that the flaxseed oil is probably not required for this effect. Further presumptive evidence for the ability of flaxseed to assist in the reduction of coronary heart disease was recently presented at a national meeting.(48) Dr. Frank Hu, a researcher at Harvard University's School of Public Health, presented his findings on the association between the consumption of ALA and the reduced risk of coronary heart disease in women. Dietary consumption of ALA, a polyunsaturated acid fat, is essential for health because the body does not synthesize ALA. Fortunately, ALA is present in many foods such as flaxseed, walnuts, and corn oil. Hu and his colleagues studied the records of 70,000 women enrolled in the nationwide Nurses' Health Study. Beginning in the mid-1980s and for the next 14 years, Dr. Hu noted: "We found that a higher intake of ALA is associated with lower risks of coronary heart disease." He also noted that these study results were consistent with those of studies on laboratory animals. He cautiously proclaimed these findings needed to be confirmed by clinical human trials.

MALARIA AND RHEUMATOID ARTHRITIS

Research on the effects of flaxseed or its oil as a potential treatment for malaria and rheumatoid arthritis (RA) is still in its early stages. While it is too early to speculate whether either of these diseases will be ameliorated by consumption of flaxseed, some interesting results have been reported.
For example, Levander and Ager(49) reported on the possible antimalarial effects of flaxseed and its oil in the diet. In research with Vitamin E-deficient mice, when either ground flaxseed or flaxseed oil was incorporated into their diets the authors observed strong antimalarial properties. They believe that this activity was due to the presence of high amounts of ALA in flaxseed. They noted that much research on using fish (high in omega-3 fatty acids [Omega-3 FA]) as a treatment for malaria is being carried on throughout the world. Since the ALA in flaxseed is also an Omega-3 FA, they hypothesized that linseed oil warrants further research as a palliative for human malaria strains.
Flaxseed oil is also receiving attention as a possible treatment for RA. It is known that two cytokines have been implicated as mediators in the joint pathology that occurs in the inflammatory disorder RA. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-l-beta (IL-l-beta) are known to be present in rheumatoid joints. Caughey et al,(50) investigated substituting flaxseed oil for treatment of RA with fish oils. In healthy human volunteers, they found approximately 30 percent reductions in the synthesis of both TNF-alpha and IL-1-beta when flaxseed oil was part of their diet. Cytokine reductions were greater (74 percent and 80 percent, respectively) when fish oils were used. Additional research is underway to evaluate the possibility for combining the use of plant and fish oils where conditions warrant less fish oil use.

CONCLUSION

Flax or its byproducts have served humankind as a food, fiber, herbal, and in many other ways since prehistoric times. Today both the seed and its oil are being assessed through medical research as nutritional supplements for the cure or the alleviation of some of the serious diseases that plague humankind. Early results are quite promising. Perhaps in the near future, flax's health benefits will become one of the brilliant facets of this herbal jewel.

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