Flaxseed’s role as the "nutraceutical food of the 21st century" is enhanced by its potential effect on breast and colon cancer prevention, according to Dr. Lilian Thompson, Professor, Department of Nutritional Sciences, Faculty of Medicine, University of Toronto. Dr. Thompson was part of the symposium "Flaxseed in Human Nutrition" at the 16th International Congress of Nutrition in Montreal in July 1997. Dr. Thompson presented data on flaxseed and its effect on breast and colon cancer prevention. Flaxseed is the richest plant source of lignan precursors — important because the lignans that mammals produce from this food precursor have been shown to be protective against breast and colon cancer. In animal studies, Dr. Thompson found that flaxseed affects all three stages of cancer development — initiation, tumour development and tumor growth and spread. "Human studies are needed to confirm, but flaxseed has tremendous potential to positively affect our health," Dr. Thompson said.

Flaxseed contains Secoisolariciresinol diglucoside (SDG), a potent antioxidant and a known precursor of the mammalian lignans, enterolactone and enterodiol. These compounds have other pharmacological properties including phytoestrogen properties similar to isoflavones. Studies performed in the Department of Physiology, College of Medicine, University of Saskatchewan, have shown that SDG prevents the development of hypercholesterolemic atherosclerosis, reduces total cholesterol and LDL-cholesterol, and has a tendency to raise HDL-cholesterol in animal models. In addition, SDG has shown the ability to lower blood pressure, and has demonstrated that it is effective in preventing diabetes mellitus (Type I and Type II) and endotoxic shock.

New (soft) technologies (as pioneered by Gaia Research) can produce products that extend the nutraceutical properties ascribed to flaxseed while minimizing drawbacks associated with the consumption of whole flaxseed, which are usually consumed associated with baked goods, which damages the EFA’s and other healthful components. Correctly processed raw flaxseed can have reduced levels of the strong laxative/purgative effects normally associated with the high cyanogenic glycoside mucilage component of flaxseed, which otherwise releases toxic hydrogen cyanide via auto-hydrolysis in the presence of water in the gut. Although this is associated with a non-targeted additional laetrile-type of anti-cancer effect, it strongly limits the amount of the most healthful SDG, which could otherwise be consumed. A typical concentration of SDG in oil-free flaxseed is around 1.5%. Careful processing can concentrate the SDG, whilst reducing the glycosides, allowing for a much-reduced gastric challenging serving size suitable for an optimal daily dosage.

Secoisolariciresinol diglucoside (SDG), an antioxidant in flaxseed, is metabolized in the body and these metabolites have antioxidant activity which are even more potent than SDG. The effectiveness of SDG in hypercholesterolemic atherosclerosis, diabetes, and endotoxic shock could be due to these metabolites. (Prasad K, Int. J. Angiol, 9(4): 220, 2000)

Flaxseed and its lignan secoisolariciresinol diglycoside (SDG) inhibit mammary tumor development in rats. Increased plasma insulin-like growth factor I (IGF-I) concentrations are associated with increased breast cancer risk. The anticancer effect of flaxseed and SDG may be related, in part, to reductions in plasma IGF-I.
(Rickard S, et al, Cancer Lett, 8; 161(1): 47, 2000)

Reactive oxygen species (ROS) have been implicated in the development of diabetes mellitus. SDG isolated from flaxseed is an antioxidant. An investigation was made of the effects of SDG on the development of diabetes in rat, to determine if SDG can prevent/reduce the development of diabetes and if this prevention/reduction is associated with reduction in oxidative stress. RESULTS: SDG prevented the development of diabetes by 75%.
(Prasad K, et a, Mol Cell Biochem, 206(1-2): 141, 2000; Prasad K, Mol Cell Biochem, 209(1-2): 89, 2000)

Flaxseed SDG may have a therapeutic role in lupus nephritis.
(Clark W, et al Lupus, 9(6): 429, 2000)

Dietary estrogens, such as lignan-rich flaxseed, are similar in structure to endogenous sex steroid hormones and act in vivo to alter hormone metabolism and reduce subsequent cancer risk in postmenopausal women.
(Hutchins A, Cancer Epidemiol Biomarkers Prev, 9(10): 1113, 2000)

Asian men have much lower incidences of prostate cancer and possibly of benign prostatic hyperplasia (BPH) than their Western counterparts. Vegetarian men also have a lower incidence of prostate cancer than omnivorous males. Plant lignans give rise to the mammalian lignans, enterodiol and enterolactone; the richest source is linseed (flaxseed). In addition to their oestrogenic activity, these plant compounds can interfere with steroid metabolism and bioavailability, and also inhibit enzymes, such as tyrosine kinase and topoisomerase, which are crucial to cellular proliferation and hence may contribute to lower incidences of prostate cancer.
(Eur Urol, 35(5-6): 377, 1999)

Flaxseed ingestion produces large amounts of mammalian lignans with weak estrogenic/anti-estrogenic properties reduced adult relative prostate weight and cell proliferation, suggesting potential protection against prostatic disease, without affecting sex hormone levels.
(Tou J, et al, J Toxicol Environ Health, 56(8): 555, 1999)

SDG is a plant lignan isolated from flaxseed. Lignans are platelet-activating factor-receptor antagonists that inhibit the production of oxygen radicals by polymorphonuclear leukocytes. SDG is an antioxidant. Antioxidants studied thus far are known to reduce hypercholesterolemic atherosclerosis. Research suggests that SDG reduces hypercholesterolemic atherosclerosis and that this effect is associated with a decrease in serum cholesterol, LDL-C, and lipid peroxidation product and an increase in HDL-C and antioxidant reserve.
(Prasad K, Circulation, 99(10): 1355, 1999)

Phytoestrogens are diphenolic compounds that are present in several plants eaten by human beings. Flaxseed is a particularly abundant source of phytoestrogens. When ingested in relatively large amounts, phytoestrogens have been shown to have significant estrogen agonists/antagonists effects in animals and humans. There is epidemiological, laboratory and clinical evidence which indicates that phytoestrogens, like certain selective estrogen receptor modulators, have an antiproliferative effect on the breast, and positive effects on the lipoprotein profile and bone density. They might also improve some of the climacteric symptoms.
(Brzezinski A & Debi A, Eur J Obstet Gynecol Reprod Biol, 85(1): 47, 1999)

The antioxidant activities of the flaxseed lignan secoisolariciresinol diglycoside (SDG) and its mammalian lignan metabolites, enterodiol (ED) and enterolactone (EL), were evaluated in both lipid and aqueous in vitro model systems. All three lignans significantly (p < or = 0.05) inhibited the linoleic acid peroxidation at both 10 and 100 microM over a 24-48 h of incubation at 40 degrees C. The efficacy of SDG and particularly the mammalian lignans ED and EL to act as antioxidants in lipid and aqueous in vitro model systems, at relatively low concentrations (i.e. 100 microM), potentially achievable in vivo, is an evidence of a potential anticarcinogenic mechanism of flaxseed lignan SDG and its mammalian metabolites ED and EL.
(Kitts D, et al, Mol Cell Biochem, 202(1-2): 91, 1999)

Flaxseed, the richest known source of plant lignans, has been shown to have chemo-protective effects in animal and cell studies. Some of its effects may be mediated through its influence on endogenous hormone production and metabolism. Flaxseed supplementation significantly increased urinary 2-OHEstrogen excretion (p < 0.0005) and the urinary 2/16 alpha-OHE1 ratio (p < 0.05) in a linear, dose-response fashion. These results suggest that flaxseed may have chemo-protective effects in postmenopausal women. (Haggans C, et al, Nutr Cancer, 33(2): 188, 1999)

Flaxseed is high in secoisolariciresinol diglycoside (SDG), the precursor of mammalian lignans, which can affect mammary gland structures. Lifetime or gestation and lactation exposure to 5 or 10% flaxseed induce structural changes in the mammary gland that may potentially reduce mammary cancer risk.
(Tou J & Thompson L, Carcinogenesis, 20(9): 1831, 1999)

Flaxseed and SDG, regardless of dose, appeared to delay the progression of MNU-induced mammary tumorigenesis. (Rickard S, et al, Nutr Cancer; 35(1): 50, 1999)

Dietary supplementation with flaxseed or its lignan SDG has reduced induced mammary tumor size and number in rats. There was a dose-dependent effect of SDG on tumor multiplicity, lowest in the HSDG group (high SDG 5%) and highest in the LSDG (low SDG 2.5%) group throughout treatment, indicating that HSDG inhibited, whereas LSDG promoted, MNU-induced mammary tumor development. Tumor invasiveness and grade were decreased in all treatment groups compared with the BD (basal diet). Flaxseed and SDG treatment, regardless of dose, appeared to delay the progression of MNU-induced mammary tumorigenesis. (Rickard S, et al, Nutr Cancer; 35(1): 50, 1999)

Because flaxseed and its lignans are colon cancer protective, it is concluded that, in contrast to other studies, beta-glucuronidase activity may play a beneficial role in their presence by increasing mammalian lignan absorption and enterohepatic circulation. (Jenab M, et al, Nutr Cancer, 33(2): 154, 1999)

Flax seed is the richest source of omega-3 fatty acid and lignans. Omega-3 Fatty acid suppresses the production of interleukin-1 (IL-1), tumor necrosis factor (TNF) and leukotriene B4 (LTB4), and of OFRs by polymorphonuclear leukocytes (PMNLs) and monocytes. Lignans possess anti-platelet activating factor (PAF) activity and are antioxidant. PAF, IL-1, TNF and LTB4 are known to stimulate PMNLs to produce OFRs. Flaxseed would, therefore, reduce the levels of OFRs and hence would prevent the development of hypercholesterolemic atherosclerosis. In rabbits, flax seed reduced the development of aortic atherosclerosis by 46% and reduced the PMNL-CL without significantly lowering the serum cholesterol. Flax seed in normocholesterolemic rabbits increased serum total cholesterol and decreased PMNL-CL without significantly affecting the serum TG. Modest dietary flax seed supplementation is effective in reducing hypercholesterolemic atherosclerosis markedly without lowering serum cholesterol. Its effectiveness against hypercholesterolemic atherosclerosis could be due to suppression of enhanced production of OFRs by PMNLs in hypercholesterolemia. Dietary flax seed supplementation could, therefore, prevent hypercholesterolemia-related heart attack and strokes. (Ogborn M, et al, Kidney Int 55(2): 417, 1999)

Dietary supplementation with secoisolariciresinol diglycoside (SDG), a lignan precursor isolated from flaxseed, significantly reduced pulmonary metastasis of melanoma cells and inhibited the growth of metastatic tumors that formed in the lungs. (Li D, et al, Cancer Lett, 142(1): 91, 1999)

Flaxseed, the richest source of lignans reduces metastasis and inhibits the growth of the metastatic secondary tumors in animals. Flaxseed may be a useful nutritional adjuvant to prevent melanoma metastasis in cancer patients. (Yan L, et al, Cancer Lett, 124(2): 181, 1998)

Flaxseed contains lignans that have antioxidant activites and inhibit platelet-activating factor (PAF). Pretreatment with flaxseed attenuated endotoxin induced cardiac dysfunction and cellular damage. Flaxseed antioxidant and anti-PAF agents may be effective in the treatment of ET shock. (Pattanaik U & Prasad K, J Cardiovasc Pharmacol Ther, 3(4): 305, 1998)

Ground flaxseed modulated inflammatory response, but did not prevent macrophages from killing bacteria (Babu U et al, (Food And Drug Administration), Experimental Biology 94, Parts I And II : April 1994, Faseb Journal, 1994); (Babu U, et al, Life Sci, V 60:545, 1997)

The mammalian lignans enterolactone (EL) and enterodiol (ED) derived from precursors in foods, particularly flaxseed, have been shown to reduce the mammary tumor growth due to their antiestrogenic properties. Lignans are growth inhibitors of colon tumor cells and they may act through mechanism(s) other than antiestrogenic activity. (Sung M, et al, Anticancer Res 18(3A: 1405, 1998)

Flaxseed and its mammalian lignan precursor SDG have been shown to be mammary cancer-protective in rats. The anti-estrogenic effects of flaxseed and SDG were compared with tamoxifen, an antiestrogen, by monitoring rat estrous cycling. Four-week supplementation of a high-fat diet with flaxseed (2.5-10%) or SDG (0.75, 1.5 or 3.0 mg/day) produced a dose-related cessation or lengthening (by 18-39%) of estrous cycles in up to 66% of rats. With tamoxifen (1 mg/kg body weight/day), 83% of the animals had irregular cycles or were in persistent diestrus. Flaxseed and SDG were anti-estrogenic without gross tissue toxicity. (Orcheson L, Cancer Lett, 125(1-2): 69, 1998)

Flax seed is the richest source of omega-3 fatty acid and lignans. Omega-3 fatty acid suppresses the production of interleukin-1 (IL-1), tumor necrosis factor (TNF) and leukotriene B4 (LTB4), and of OFRs by polymorphonuclear leukocytes (PMNLs) and monocytes. Lignans possess anti-platelet activating factor (PAF) activity and are antioxidant. PAF, IL-1, TNF and LTB4 are known to stimulate PMNLs to produce OFRs. Flaxseed would, therefore, reduce the levels of OFRs and hence would prevent the development of hypercholesterolemic atherosclerosis. Flax seed reduced the development of aortic atherosclerosis by 46% and reduced the PMNL-CL without significantly lowering the serum cholesterol. Modest dietary flax seed supplementation is effective in reducing hypercholesterolemic atherosclerosis markedly without lowering serum cholesterol. Dietary flax seed supplementation could, therefore, prevent hypercholesterolemia-related heart attack and strokes. (Prasad K, Atherosclerosis, 132(1): 69, 1997)

Flaxseed, the richest source of mammalian lignan precursors, such as secoisolariciresinol diglycoside (SD), has been shown over the short term to decrease some early markers of colon cancer risk. This study determined that flaxseed has a colon cancer protective effect, that it is due, in part, to SD and that the protective effect of flaxseed is associated with increased beta-glucuronidase activity. (Jenab M & Thompson L, Carcinogenesis, 17:1343, 1996)

Flaxseed, a rich source of mammalian lignan precursor secoisolariciresinol-diglycoside (SD) and alpha-linolenic acid (ALA), has been shown to be protective at the early promotion stage of carcinogenesis. In conclusion, the SD lignans in flaxseed appears to be beneficial throughout the promotional phase of carcinogenesis whereas the oil component is more effective at the stage when tumors have already been established. (Thompson L, et al, Carcinogenesis, 17:1373, 1996)

Secoisolariciresinol diglycoside (SD), a mammalian lignan precursor found in flaxseed and tested for effects on mammary tumorigenesis, resulted in a 37% reduction (p < 0.05) in the number of tumors per tumor-bearing rat and a 46% reduction (p < 0.05) in the number of tumors per number of rats in each group. This study showed, for the first time, that SD has an antitumor effect when provided at the early promotion stage of tumorigenesis. (Thompson L, et al, Nutr Cancer, 26:159, 1996)

Flaxseed 18-3 (n-3) alpha-linoleic acid showed a marked immunomodulatory effect on the exhaustive exercise-related immunosuppression, as compared to the effects of other PUFA. (Benquet C, et al, J Toxicol Environ Health, 43: 225, 1994)

Flaxseed lignans have antitumor, antimitotic, antioxidant and weak estrogenic activities, are potentially the richest source of phytoestrogens in the human diet and may be linked to a low incidence of breast and colon cancer. Secoisolariciresinol was discovered to be a very potent antioxidant similar to BHA. No toxicity was found in the lignans. (Obermeyer W, et al (US Food and Drug Administration, Center for Food Safety and Applied Nutrition, Div. Contaminants Chem., Natural Products Branch), Meeting Of The Federation Of American Societies For Experimental Biology On Experimental Biology March/April, 1993, Faseb J (Fed Am Soc Exp Biol), A863, 1993)

Flaxseed ingestion produces potentially anticarcinogenic lignans in the colon. This study determined that flaxseed decreases the risk for colon carcinogenesis. In the descending colon of supplemented groups, the total number of aberrant crypts and foci were significantly reduced by 41-53% and 48-57%, respectively. Flaxseed may reduce the risk for colon carcinogenesis. (Serraino M & Thompson L, Cancer Lett, 63:159, 1992)

Vitamin E-deficient diets containing 5 to 20% ground flaxseed protected mice against the malarial parasite Plasmodium voelii as shown by decreased parasitemia and enhanced survival. (Levander O, et al, (USDA/ARS Human Nutrition Research Center, Vitamin Mineral Nutrition Laboratory), Nutrition Research, 11, 1991)

Since lignans have been suggested to have some cancer-protective effects, flaxseed, the most abundant source of lignan precursors, was tested for its effect on early markers of risk for mammary carcinogenesis. Supplementation of a high-fat diet with flaxseed flour (FF) or defatted flaxseed meal (FM) (5% or 10%) reduced the epithelial cell proliferation by 38.8-55.4% and nuclear aberrations by 58.8-65.9% in female rat mammary gland, with optimum effects seen with the 5% FF. These protective effects were accompanied by increases in urinary lignan excretion indicating that they may be related to the ability of flaxseed to provide lignan precursors. (Serraino M & Thompson L, Cancer Lett, 60:135, 1991)


Nutritional profile of whole flaxseeds

Two (2) tablespoons provide the following naturally occurring fatty acids, lignin fiber and lignan:

Alpha Linolenic Acid (Omega-3) ........................1,710 mg

Linoleic Acid (Omega-6) ..............................……480 mg

Oleic Acid (Omega-9) .....................................…540 mg

Lignin Fiber ...................................................…1,003 mg

Lignan ...........................................................…13.6 mg

Nutrients per 100 gr of flax: Thiamin - .03 mg; Riboflavin - .1 mg; Niacin - 5 mg; Pyridoxine - 10 mg; Pantothenic Acid - 7 mg; Calcium - 410 mg; Phosphate - 880 mg; Sodium - 32 mg; Potassium - 880 mg; Iron - 8.3 mg; Magnesium - 750 mg; Zinc - 12 mg; Copper - 1 mg; Manganese - 2.1 mg; Boron 3 mg; Chromium - 0.5 mg; Vitamin E - 0.6 I.U.; Vitamin A - 10 I.U. Protein: Alamine - 4.0 g; Arginine - 10.8 g; Aspartic Acid - 10.0 g; Cystine - 3.8 g; Glutamic - 20.2 g; Glycine - 6.0 g; Histidine - 2.9 g; Isoleucine - 4.6 g; Leucine - 6.2 g; Lysine - 3.9 g; Methionine - 2.3 g; Phenylalanine - 4.5 g; Proline - 4.5 g; Serine - 3.2 g; Threonine - 4.6 g; Tryptophan - 2.3 g; Tyrosine - 2.7 g; Valine - 5.2 g.

Linum usitatissimum

Nutrient Units 1 cup
155.000 g
Water g 13.562
Energy kcal 762.600
Energy kj 3191.450
Protein g 30.225
Total lipid (fat) g 52.700
Carbohydrate, by difference g 53.087
Fiber, total dietary g 43.245
Ash g 5.425
Calcium, Ca mg 308.450
Iron, Fe mg 9.641
Magnesium, Mg mg 561.100
Phosphorus, P mg 771.900
Potassium, K mg 1055.550
Sodium, Na mg 52.700
Zinc, Zn mg 6.463
Copper, Cu mg 1.614
Manganese, Mn mg 5.086
Selenium, Se mcg 8.525
Vitamin C, ascorbic acid mg 2.015
Thiamin mg 0.264
Riboflavin mg 0.248
Niacin mg 2.170
Pantothenic acid mg 2.372
Vitamin B-6 mg 1.437
Folate mcg 430.900
Vitamin B-12 mcg 0.000
Vitamin A, IU IU 0.000
Vitamin A, RE mcg_RE 0.000
Vitamin E mg_ATE 7.750
Fatty acids, saturated g 4.954
4:0 g 0.000
6:0 g 0.000
8:0 g 0.000
10:0 g 0.000
12:0 g 0.000
14:0 g 0.000
16:0 g 2.793
18:0 g 2.161
Fatty acids, monounsaturated g 10.645
16:1 g 0.000
18:1 g 10.645
20:1 g 0.000
22:1 g 0.000
Fatty acids, polyunsaturated g 34.782
18:2 g 6.693
18:3 g 28.089
18:4 g 0.000
20:4 g 0.000
20:5 g 0.000
22:5 g 0.000
22:6 g 0.000
Cholesterol mg 0.000
USDA Nutrient Database for Standard Reference, Release 12 (March 1998)

Cyanogenic Glycosides

Flaxseed is increasingly being used in some food products because of its high content of alpha-linolenic acid and dietary fibre. However, flaxseed contains cyanogenic glycosides, which release toxic hydrogen cyanide in the presence of water (autohydrolysis). (Chadha R, et al (Food Research Division, Bureau of Chemical Safety, Ottawa, Ontario, Canada), Food Addit Contam, 12: 527, 1995) Cyanogenic glycosides (linamarin, linustatin, neolinustatin) were highest in extracted flaxseed mucilage. We conclude that up to 50 g high-alpha-linolenic acid flaxseed is palatable, safe and may be nutritionally beneficial in humans by raising n-3 fatty acids in plasma and erythrocytes and by decreasing post-prandial glucose responses. Cunnane S, et al, (University of Toronto, Toronto, Canada) Br J Nutr, 69:443, 1993)

The presence of cyanogenic glycosides and diglucosides in flaxseeds is a concern, as they may release cyanide upon hydrolysis. In addition, the polyunsaturated fatty acids may undergo thermal or auto-oxidation (rancidity) when exposed to air or high temperatures that are used in food preparation (& needed to detoxify the cyanogenic glycosides in the mucilage). Cyanide levels produced as a result of autolysis, are below the harmful limits to humans (remember however that “the dose maketh the poison”). (Wanasundara P & Shahidi F, Adv Exp Med Biol, 434: 307, 1998)

Cyanogenic Glycosides in Flaxseed

By Robin J. Marles, Ph.D.

The presence of cyanogenic glycosides in the diet is significant only in relation to dose and the nutritional status of the consumer. Flax seed meal contains two cyanogenic glycosides, linustatin and neolinustatin. Many foods are slightly cyanogenic (e.g. wheat and barley!), probably as an evolutionary adaptation to discourage herbivory, and our body has a limited capacity to detoxify low concentrations of cyanide through addition of sulphur (from amino acids) to form thiocyanate or reaction with cysteine directly to form beta-cyanoalanine. Thus if the dietary levels of sulphur-containing amino acids are high the body can resist a low intake of cyanide, but if the diet is low in protein overall or due to imbalances in vegetable protein amino acid composition it is low in the sulphur-containing amino acids, then we see toxicity.

The two most common symptoms of chronic cyanide intoxication are goitre, probably caused by high levels of thiocyanate formation where dietary protein levels are adequate and the detoxification mechanism is operating in high gear but the body can't clear the thiocyanate product quickly enough, and fibrocalculous pancreatic diabetes associated with protein malnutrition, where toxicity is probably directly due to cyanide because of the lack of adequate detoxification. Few of us are likely to consume significant quantities of flax seed, nor are those people consuming flax seed likely to have protein malnutrition.

Robin J. Marles, Ph.D.
Associate Professor, Botany Department
Brandon University, Brandon, MB R7A 6A9 CANADA

The Effect of Flax Seed on Menstrual Cycles

Haynes K & Kier K, R.Ph., M.Sc., Professor of Clinical Pharmacy, Ohio Northern University

For years, people have been attempting to control menstrual cycles. Controlling menstrual cycles has benefits including, decreasing the risk of breast cancer.1 Flax, traditionally used as a dietary source of fiber, is a primary source of plant lignans1,2 and alpha -linolenic acid (18:3n-3).3 Flax’s high levels of alpha -linolenic acid can lower total cholesterol and low-density lipoprotein cholesterol.4 Lignans and alpha-linolenic acid have significant effects on the menstrual cycle.1,3

Flax is composed of lignans, or phytochemicals, which structurally resemble estrogens. Secoisolariciresinol diglycoside (SDG) is the primary plant lignan found in flax, which has shown anti-tumor effects in animal studies.3,5 SDG is converted to enterodiol and enterolactone the main mammalian lignans.5,6 Intestinal bacteria are responsible for the conversion of SDG to enterodiol and enteriolactone. Recent studies show these mammalian lignans act as weak estrogen antagonists.2,6,7

According to Phipps et. al., the effect of the phytochemicals on the menstrual cycle is a lengthening of the luteal phase (LP), larger LP Progesterone/Estrogen (P/E2) ratios, fewer anovulatory cycles and a lower tendency for ovarian dysfunction. Flaxseed (linseed) ingestion had no direct effect on the LP progesterone concentration, but the LP progesterone/estradiol ratios were elevated; this was due to a decreased LP estradiol (E2) concentration. The women supplemented their diets with a dose of 10g/day of flax during the flax cycles. Between the flax cycles and the control cycles, no significant alterations of weight, total calories, fat, protein, or carbohydrate levels occurred.2 There was a small rise in fiber content noted during the flax cycles, due to the fiber associated with flax.7 Flaxseed had no significant changes on the follicular phase. A crossover study had women ingesting their normal diets for the first cycle, and then subjects consumed flax supplements during cycles 2-4 or cycles 5-7.2 Concentrations of the lignans measured in the urine6 and fecal matter7 showed the levels of lignans absorbed. Clearly, flax has a significant impact on controlling women’s menstrual cycles.

The control flaxseed has over the menstrual cycle has an influence on cancer growth.2 The estrogen window hypothesis proposed by Korenman states that luteal inadequacy, ovarian dysfunction, and normal estrogen stimulation characterized by a decreased progesterone secretion is a major cause of breast cancer.8 Studies show a linkage between ovarian dysfunction and breast cancer risk; flax controls this dysfunction through regulation. Flax increases the LP of women and decreases the tendency for ovarian dysfunction.2 There are conflicting reports, showing regular cycling, as opposed ovulatory dysfunctional cycles, are a major risk. This study states mitotic activity of breast cancer cells tends to reach a peak during LP, which is in contrast to endothelial cancer cells. According to the study, the less time a woman spends in the luteal phase the lower the breast cancer risk.9 The popular drug tamoxifen is structurally similar to the lignans. Tamoxifen has similar properties including increasing LP estrogen and progesterone concentrations and lengthening the LP. Another essential component of flax, enterolactone combined with estradiol inhibits MCF-7 breast cancer cell growth in vitro. Interestingly, enterolactone alone or estradiol alone promotes breast cancer cell growth.10 If used effectively and under supervision, flax may have the power to control irregular cycling, inhibit growth of breast cancer cells, and therefore may prevent the development of cancerous tissue in some women.

The other important component of flax is alpha -linolenic acid (ALA), an n-3 omega essential fatty acid.11 ALA enhances mental development,12 is a precursor to eicosanoids,13 and helps maintain a normal pregnancy.14 Diets lacking in essential fatty acids have shown increased reproductive failure, irregular ovulation, infertility, prolonged gestation, excessive hemorrhaging at parturition and higher incidence of still birth. ALA, found in flax, improves reproductive function.13,14 The n-3 fatty acid is responsible for vision and neuronal development primarily during the fetal and postnatal periods. Retinal and neuronal development is determined by eicosapentaenoic acid (20:5n-3) and ALA concentrations.13 The n-3 requirements of the fetus are higher then the requirements of the suckling offspring.12 The majority of the studies show the relationship between ALA and development.

Epidemiological studies show an association between the risk of further metastasis and fatty acid intake. In a cohort study involving 121 breast cancer patients, the risk of subsequent metastasis lowered when ALA was above 0.38 percentage. A reduction in ALA concentrations in breast adipose tissue proceeds metastasis of cancer; dietary supplementation of ALA might delay or prevent clinical appearance of metastasis. Decreased breast cancer incidence and improved survival is associated with higher n-3 fatty acid intake.15 Human clinical trials will prove the true value of flax.

Many women and practitioners are finding out about flax and other herbals on the Internet. The Internet is full of ideas on the medical uses of flaxseed. According to the web site http://www.flax.com/ a lignan is a powerful antioxidant; bacterial enzymes in the intestinal tract convert flax to anti-estrogen compounds. These compounds prevent excess levels of estrogen from causing estrogen-related tumors.11 A second site in Canada, where flaxseed ingestion is higher, states lignans stimulate the synthesis of sex hormone binding globulins which decrease the levels of estrogen by inhibiting binding.5 These pages are part of Canada’s Flax Council. The Flax Council noted the effects of flaxseed on the initiation, promotion, and tumor growth phases of breast and colon cancer.16 The information posted on these Internet pages is consistent with literary articles; the pages suggest a need for long-term studies.17

The Internet has several sites discussing the importance of essential fatty acids including omega-3 (alpha -linolenic acid).18 The ALA breaks down to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the three fatty acids help to fortify the yolks. These fatty acids thin the blood and may lower the risk of heart attacks. A word of warning needs to go to patients already on anticoagulants.5 The Flax Council suggests 0.16g of omega-3 during the second and third trimesters of pregnancy and increased intake for lactating women. The optimal intake of ALA is estimated to be 800-1100 mg/day. Flax is an excellent source of essential polyunsaturated fatty acids, but lacks monounsaturated and saturated fatty acids.5

Many health magazines are making flaxual claims. An article in Prevention magazine, cited several reasons to include flax in the daily diet. The article states that ALA is effective in relieving menstrual cramps. According to the article, flax is the highest source of alpha-linolenic acid. A typical dose for flax ranges from 6-25 grams a day.

According to Essential Nutrient Research Company, (ENRECO) Flax contains: Lignans - 800mg/kg

All of these components have beneficial applications.11 Flax, like other herbals, requires the proper exercise and diet to be effective. Some remedies flax include female disorders, colon problems, inflammation and cancerous tumors. The oil of flaxseed promotes stronger nails, bone, teeth and skin.20 Not all of these claims have significant testing to prove efficacy. Flaxseeds are richer in essential fatty acids than fish oil. Flax oil is better than fish oil because fish oil only contains a trace amount of ALA.5

There is sound evidence for the use of flax as a means to control or at least help to regulate menstrual cycles. Flax lignans reduce the risk of cancer including breast cancer. ALA is beneficial in the reduction of total cholesterol. Mahatma Gandhi once said, "Wherever flax seed becomes a regular food item among the people, there will be better health."11


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    19. McCord H. Top seed. Prevention Magazine 1997; 49:81-85.

    20. "Alternative Medicine – Flaxseed, Flax Focus www.alternative-medicines.com/1flaxsee.htm. January, 1998.

The Phipps Study. Abstract. Lignans are a group of phytochemicals shown to have weakly estrogenic and antiestrogenic properties. Two specific lignans, enterodiol and enterolactone, are absorbed after formation in the intestinal tract from plant precursors particularly abundant in fiber-rich food and are excreted in the urine. We evaluated the effect of the ingestion of flax seed powder, known to produce high concentrations of urinary lignans, on the menstrual cycle in 18 normally cycling women, using a balanced randomized cross-over design. Each subject consumed her usual omnivorous, low fiber (control) diet for 3 cycles and her usual diet supplemented with flax seed for another 3 cycles. The second and third flax cycles were compared to the second and third control cycles. Three anovulatory cycles occurred during the 36 control cycles, compared to none during the 36 flax seed cycles. Compared to the ovulatory control cycles, the ovulatory flax cycles were consistently associated with longer luteal phase (lp) lengths (mean +/- sem, 12.6 +/- 0.4 Vs. 11.4 +/- 0.4 Days; p = 0.002). There were no significant differences between flax and control cycles for concentrations of either estradiol or estrone during the early follicular phase, midfollicular phase, or lp. Although flax seed ingestion had no significant effect on lp progesterone concentrations, the lp progesterone/estradiol ratios were significantly higher during the flax cycles. Midfollicular phase testosterone concentrations were slightly higher during flax cycles. Flax seed ingestion had no effect on early follicular phase concentrations of dhea-s, prl, or sex hormone-binding globulin. Our data suggest a significant specific role for lignans in the relationship between diet and sex steroid action, and possibly between diet and the risk of breast and other hormonally dependent cancers. (Phipps W, et al, J Clinl Endocrinol Metab, 77(5), 1993)

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