While marine algae have traditionally formed part of the Oriental diet, their major use in Western countries has been in the phytocolloid industry. Only a few coastal communities outside Asia have customarily used seaweeds as components of special dishes. Of late, however, seaweeds have gained importance as foodstuffs in Western countries and most recently as components of functional foods because of their high dietary fiber, mineral, vitamin, and phytochemical content, low energy levels, and high concentrations of certain polyunsaturated fatty acids. The present paper reviews the available data for some of the components of the major edible algae and studies several factors that can affect their physiochemical properties (e.g., hydration, water and oil-holding capacity, fermentability, binding capacity, etc.) and, in turn, their nutritional importance. The effects of marine alga consumption on growth and body weight, mineral availability, lipid metabolism, blood pressure, and antioxidant properties are reviewed, together with preliminary data on the effects of some functional foods containing seaweeds on lipid metabolism and gene expression of enzymes engaged in antioxidant protection. This review concludes with some remarks regarding the danger of the improper use of seaweeds in herbal medications. In addition, as the properties of algae are highly dependent on their individual composition, any generalization regarding these properties may be considered misleading and scientifically inappropriate.

The present paper compares the effects of two monounsaturated oils, extra virgin olive oil (EVOO) and high-oleic acid sunflower oil (HOSO), on serum and LDL peroxides, eicosanoid production and the thrombogenic ratio (thromboxane (TX) B 2 :6-keto-prostaglandin F 1a ) in fourteen non-obese post-menopausal women. The subjects, mean age 63 (SD 11) years, were assigned to two consecutive oleic acid-rich 28 d dietary periods. EVOO and HOSO represented 62 % of the total lipid intake and were used as the only culinary fat during the first and second dietary periods respectively. Serum peroxides, plasma a-tocopherol and TXB 2 levels in stimulated platelet-rich plasma (PRP-TXB 2 ) were significantly higher (P , 0´01Y P , 0´001Y and P , 0´05 respectively) after the HOSO diet than after the EVOO diet. The relationship between the serum cholesterol level (,6´21 mmol/l or $6´21 mmol/l) and the type of dietary oil on eicosanoids, peroxides and a-tocopherol were evaluated by two-way ANOVA. Dietary oil significantly affected P , 0´05 the PRP-TXB 2 level, whereas serum and LDL peroxides were significantly affected P , 0´001 and P , 0´01 respectively) by the serum cholesterol level. The plasma a-tocopherol level was significantly affected by the serum cholesterol level and the type of dietary oil (both P , 0´001X No significant relationships were found between serum cholesterol levels, serum peroxide or LDL peroxide levels, plasma a-tocopherol concentrations or a-tocopherol intakes with eicosanoid production or the thrombogenic ratio due to dietary changes. However, in spite of their higher a-tocopherol levels, hypercholesterolaemic subjects showed increased peroxidation in serum and LDL in comparison with normocholesterolaemic subjects on the HOSO diet in comparison with the EVOO diet. These findings suggest that differences in the type of minor compounds, as well as in the concentration of linoleic acid, in both these monounsaturated oils may play an important role in modulating eicosanoid production and lipoprotein peroxidation when they constitute a large proportion of the diet of post-menopausal women.

Objective: To investigate the hypercholesterolemic effects of a dietary exchange between 16:0 and 18:1 while 18:2 was at relatively lower level ( % 4%) in aged women with initially high total serum cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) values and with high intakes of dietary cholesterol. Design: Subjects were assigned to two consecutive 28 d periods. In the ®rst period all subjects followed an oleic acid-rich diet in the form of oleic acid-rich sun¯ower oil. This was followed by a second period rich in palmitic acid in the form of palmolein. Nutrient intakes, serum lipids, lipoproteins, antioxidant vitamins, peroxides and LDL-peroxides were measured at two dietary periods. Setting: Instituto de Nutricio Ân y Bromatologõ Âa (CSIC), Departamento de Nutricio Ân y Bromatologõ Âa I (Nutricio Ân) and Seccio Ân Departamental de Quõ Âmica Analõ Âtica, Universidad Complutense, Madrid, Spain. Results: The palmolein period led to an increase in TC (P`0.001; 17.7%) and serum apolipoprotein (Apo) B levels (P`0.001; 18.0%). LDL-C and LDL-Apo B concentrations were higher (P`0.001, 4.33AE 0.94 mmolaL and P`0.01, 1.08 AE 0.20 gaL, respectively) following this period than following the oleic acid-rich sun¯ower oil diet (3.56 AE 0.85 mmolaL, 0.93 AE 0.16 gaL, respectively). No signi®cant differences were observed in the TCahigh density lipoprotein cholesterol (TCaHDL-C) ratio between the two dietary periods. Serum and LDLperoxides were lower (P`0.01, 49.5%, and P`0.001, 69.0%, respectively) after the palmolein diet than after the oleic acid-rich sun¯ower oil diet. The palmolein diet signi®cantly increased TC, LDL-C, Apo B, VLDLApoB, LDL-ApoB in women with TC ! 6.21 mmolaL or with TC`6.21 mmolaL, but the increase in Apo B, LDL-C and LDL-Apo B was greater among the women with high TC. The palmolein diet increased HDL-C in women with high or with low TC but this rise was on the borderline of statistical signi®cance (P 0.06) only in normocholesterolemics. Serum and LDL-peroxides tended to be higher in women with TC ! 6.21 mmolaL than in women with TC`6.21 mmolaL, but palmolein decreased serum and LDL-peroxide in hypercholesterolemics more than in the normocholesterolemics, resulting in serum and LDL-peroxide levels which theoretically are more adequate. Conclusions: Though palmolein increased LDL-C concentrations, it better protected LDL particles, mainly in women with high TC, against peroxidation than did oleic acid-rich sun¯ower oil. Sponsorship: This study was supported by the Spanish Comision Interministerial de Ciencia Y Tecnologõ Âa

Palmolein diet activates platelet aggregation more in normocholesterolemics. Though palmolein increased thromboxane and tended to increase prostacyclin in urine in normo- and hypercholesterolemic women, the thrombogenic ratio did not change. These effects were related to the LDL and HDL concentration increases and to the absence of change in the total cholesterol/HDL-cholesterol ratio found following the dietary intervention.

These findings suggest that the dietary exchange of an olive oil and sunflower oil blend for extra virgin olive decreases LDL and apo AII levels, and the estimate of 10-year cardiovascular risk.