Lignan content of the flaxseed influences its biological effects in healthy men and women.

OBJECTIVE: The omega-3 polyunsaturated fatty acid (n-3 PUFA) as well as lignan components of flaxseed (FLX) can have beneficial effects. In this 6-week-long, randomized, double-blinded, placebo-controlled study, we investigated the effects of FLX lignans on cardiovascular risk factors. METHODS: Thirty-seven subjects (13 men and 24 women, age: 54±7 years, body mass index [BMI]: 29.7±1 kg/m2) consumed nutrition bars with similar macronutrient contents. The fatty acid composition and the lignan contents of the bars differed significantly. Two FLX bars both contained 3.0 g of alpha linolenic acid (ALA: 18:3 n-3) but different amount of lignans (0.15 g vs. 0.41 g). RESULTS: High-lignan FLX decreased total cholesterol (C) by 12% (p=0.044), LDL-C by 15% (p=0.022), and oxidized (Ox)-LDL by 25% (p=0.035). Regular FLX tended to increase Ox-LDL by 13% (p=0.051). The difference between the effects of high-lignan vs. regular lignan FLX on Ox-LDL was highly significant (p=0.004). CONCLUSION: High-lignan FLX has the unique property of decreasing Ox-LDL, which is an independent risk factor for cardiovascular disease.

Metabolic and endocrine effects of long-chain versus essential omega-3 polyunsaturated fatty acids in polycystic ovary syndrome.

The objective of the study was to compare the effects of essential vs long-chain omega (n)-3 polyunsaturated fatty acids (PUFAs) in polycystic ovary syndrome. In this 6-week, prospective, double-blinded, placebo (soybean oil)-controlled study, 51 completers received 3.5 g n-3 PUFA per day (essential PUFA from flaxseed oil or long-chain PUFA from fish oil). Anthropometric variables, cardiovascular risk factors, and androgens were measured; oral glucose tolerance test (OGTT) and frequently sampled intravenous GTT (IVGTT) were conducted at baseline and 6 weeks. Between-group comparisons showed significant differences in serum triglyceride response (P = .0368), whereas the changes in disposition index also tended to differ (P = .0621). When within-group changes (after vs before intervention) were considered, fish oil and flaxseed oil lowered serum triglyceride (P = .0154 and P = .0176, respectively). Fish oil increased glucose at 120 minutes of OGTT (P = .0355), decreased the Matsuda index (P = .0378), and tended to decrease acute insulin response during IVGTT (P = .0871). Soybean oil increased glucose at 30 (P = .0030) and 60 minutes (P = .0121) and AUC for glucose (P = .0122) during OGTT, tended to decrease acute insulin response during IVGTT (P = .0848), reduced testosterone (P = .0216), and tended to reduce sex hormone-binding globulin (P = .0858). Fasting glucose, insulin, adiponectin, leptin, or high-sensitivity C-reactive protein did not change with any intervention. Long-chain vs essential n-3 PUFA-rich oils have distinct metabolic and endocrine effects in polycystic ovary syndrome; and therefore, they should not be used interchangeably.

Metabolic and endocrine effects of a polyunsaturated fatty acid-rich diet in polycystic ovary syndrome.

Effects of a polyunsaturated fatty acid (PUFA)-rich diet were investigated in 17 polycystic ovary syndrome (PCOS) patients. After a 3-month habitual diet period, dietary fats were partly replaced with PUFAs for another 3 months. The PUFA-rich diet increased plasma linoleic acid from 28.36 +/- 1.00% to 33.76 +/- 1.08% (P < 0.002) and alpha-linolenic acid from 0.52 +/- 0.03% to 1.06 +/- 0.10% (P < 0.0001). Fasting glucose increased from 76 +/- 3 to 95 +/- 3 mg/dl (4.2 +/- 0.2 to 5.30.2 mmol/liter; P < 0.0001), and the area under the curve for glucose during oral glucose tolerance test increased from 421 +/- 34 to 503 +/- 31 mg/dl (23.4 +/- 1.9 to 27.9 +/- 1.7 mmol/liter; P < 0.001). Plasma insulin did not change either at fasting or during oral glucose tolerance test. Fasting plasma free fatty acids decreased from 0.596 +/- 0.048 to 0.445 +/- 0.058 mg/dl (P = 0.037), and ketone bodies decreased from 9.14 +/- 1.57 to 3.63 +/- 0.62 mg/dl (895 +/- 154 to 356 +/- 61 micromol/liter; P < 0.003). Plasma 15-deoxyprostaglandin J(2) tended to decrease (from 239 +/- 65 to 171 +/- 60 ng/ml; P = 0.053). Plasma testosterone, free testosterone, SHBG, dehydroepiandrosterone sulfate, LH, FSH, and urinary estrogen conjugates did not change. Urinary pregnanediol 3-glucuronide increased from 18.6 +/- 2.2 to 31.0 +/- 5.7 micro g/mg creatinine (P = 0.038). In conclusion, increased dietary PUFA intake can exert significant metabolic and endocrine effects in women with PCOS.