Effect of flax seed ingestion on the menstrual cycle

J. CLIN. ENDOCRINOL. METAB. (USA), 1993, 77/5 (1215-1219)

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 plus or minus SEM, 12.6 plus or minus 0.4 vs. 11.4 plus or minus 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.

The effect on human tumor necrosis factor alpha and interleukin 1beta production of diets enriched in n-3 fatty acids from vegetable oil or fish oil

American Journal of Clinical Nutrition (USA), 1996, 63/1 (116-122)

The effect of a flaxseed oil-based diet on tumor necrosis factor alpha (TNFalpha) and interleukin 1 beta (IL-1beta) synthesis was examined in healthy volunteers. Use of flaxseed oil in domestic food preparation for 4 wk inhibited TNFalpha and IL-1 beta production by similar 30%. Fish-oil supplementation (9 g/d) continued for a further 4 wk; TNFalpha and IL-1beta synthesis were inhibited by 74% and 80%, respectively. There was a significant inverse exponential relation between TNFalpha or IL-1beta synthesis and mononuclear cell content of eicosapentaenoic acid (EPA), an n=3 fatty acid derived from ingested EPA (fish oil) or metabolism of ingested alpha-linolenic acid (flaxseed oil). Cytokine production decreased as cellular EPA increased to similar1% of total fatty acids. Further increases in EPA content did not result in further decreases in cytokine production. The results indicate that vegetable oils rich in n=3 fatty acids inhibit TNFalpha and IL-1beta synthesis.

Antitumorigenic effect of a mammalian lignan precursor from flaxseed

Nutrition and Cancer (USA), 1996, 26/2 (159-165)

Secoisolariciresinol diglycoside (SD), a mammalian lignan precursor found in high-fiber foods, was isolated from flaxseed and tested for effects on mammary tumorigenesis in rats fed a high-fat (20%) diet. Ingestion of purified SD at 1.5 mg/day for 20 weeks starting 1 week after treatment with the carcinogen dimethylbenzanthracene 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. Urinary mammalian lignan excretion significantly increased (p < 0.0001) with SD treatment, indicating the conversion of SD to mammalian lignans. No enlargement or gross abnormalities of the major organs were observed in the SD-treated rats. This study showed, for the first time, that SD has an antitumor effect when provided at the early promotion stage of tumorigenesis and may contribute to the health benefits of high-fiber foods.

Polyunsaturated fatty acids in treatment of acute remitting multiple sclerosis.

Br Med J (ENGLAND) Nov 18 1978, 2 (6149) p1390-1

One hundred and sixteen patients with acute remitting multiple sclerosis (MS) took part in a double-blind controlled trial of treatment with polyunsaturated fatty acids and were randomly allocated to one of four groups. Two groups received linoleic acid, one alone as a spread and one with gamma-linolenic acid in capsules (Naudicelle); and two control groups received oleic acid, one as a spread and one in capsules. Rates of clinical deterioration and frequencies of attacks were not significantly different between treated and control groups. Exacerbations were shorter and less severe in patients receiving a high dose of linoleic acid than in controls, but those receiving a lower dose--that is, Naudicelle--showed no such difference. Thus supplementing the diet with 20 g linoleic acid marginally affected the duration and severity of relapses of MS but had no effect on overall disability. The dose of Naudicelle used provided insufficient supplementation.