Sofía Ródenas

Characteristics and Nutritional and Cardiovascular-Health Properties of Seaweeds

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.

Eicosanoid production, thrombogenic ratio, and serum and LDL peroxides in normo- and hypercholesterolaemic post-menopausal women consuming two oleic acid-rich diets with different content of minor components.

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) B2:6-keto-prostaglandin F1alpha) 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 alpha-tocopherol and TXB2 levels in stimulated platelet-rich plasma (PRP-TXB2) were significantly higher (P < 0.01, P < 0.001, 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 > or = 6.21 mmol/l) and the type of dietary oil on eicosanoids, peroxides and alpha-tocopherol were evaluated by two-way ANOVA. Dietary oil significantly affected (P < 0.05) the PRP-TXB2 level, whereas serum and LDL peroxides were significantly affected (P < 0.001 and P < 0.01, respectively) by the serum cholesterol level. The plasma alpha-tocopherol level was significantly affected by the serum cholesterol level and the type of dietary oil (both P < 0.001). No significant relationships were found between serum cholesterol levels, serum peroxide or LDL peroxide levels, plasma alpha-tocopherol concentrations or alpha-tocopherol intakes with eicosanoid production or the thrombogenic ratio due to dietary changes. However, in spite of their higher alpha-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.

Lipoprotein profiles and serum peroxide levels of aged women consuming palmolein or oleic acid-rich sunflower oil diets

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 first period all subjects followed an oleic acid-rich diet in the form of oleic acid-rich sunflower 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 Nutrición y Bromatología (CSIC), Departamento de Nutrición y Bromatología I (Nutrición) and Sección Departamental de Química Analítica, 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, 4.33±0.94 mmol/L and P<0.01, 1.08±0.20 g/L, respectively) following this period than following the oleic acid-rich sunflower oil diet (3.56±0.85 mmol/L, 0.93±0.16 g/L, respectively). No significant differences were observed in the TC/high density lipoprotein cholesterol (TC/HDL-C) ratio between the two dietary periods. Serum and LDL-peroxides were lower (P<0.01, 49.5%, and P<0.001, 69.0%, respectively) after the palmolein diet than after the oleic acid-rich sunflower oil diet. The palmolein diet significantly increased TC, LDL-C, Apo B, VLDL-ApoB, LDL-ApoB in women with TC≥6.21 mmol/L or with TC<6.21 mmol/L, 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 significance (P=0.06) only in normocholesterolemics. Serum and LDL-peroxides tended to be higher in women with TC≥6.21 mmol/L than in women with TC<6.21 mmol/L, 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 sunflower oil.Sponsorship: This study was supported by the Spanish Comision Interministerial de Ciencia Y Tecnología (CICYT) Project No ALI-92-0289-C02-01.

Differences in metal and metalloid content in the hair of normo- and hypertensive postmenopausal women

This study was performed on scalp hair samples from postmenopausal women (n=26; 12 normotensives and 14 hypertensives) to determine the relationship between blood pressure and metal and metalloids in hair samples. Hair concentrations of Al, Ba, Cd, Co, Cr, Mn, Mo, Ni, Pb, Sb, Se, Sr and V were measured using inductively coupled plasma mass spectrometry, whereas Ca, Cu, Fe, K, Mg, Na and Zn concentrations were measured by inductively coupled plasma optical emission spectrometry. Methods were optimized and then validated using certified reference material GBW 09101 human hair. Although Cd, Co and Mo levels in hypertensive volunteers were significantly higher than in normotensive individuals (P<0.05), the concentrations of Fe, Mn, Na (all P<0.05) and K (P<0.001) were significantly lower. Concentrations of K (P<0.001; P<0.001) were negatively correlated with systolic and diastolic blood pressure. The concentration of Co (P=0.004; P<0.001) displayed a positive correlation with both types of pressure, whereas Cu (P=0.013) and Ni (P<0.001) concentrations correlated significantly with diastolic blood pressure and Mn negatively correlated with systolic blood pressure (P=0.031). Overweight and hypertension concurred in 27% of volunteers. This concurrence did not modify differences in hair mineral levels attributed to hypertension. The present results indicate that scalp hair concentrations of certain metals and metalloids can be used as biomarkers for hypertension in postmenopausal women.

Dietary exchange of an olive oil and sunflower oil blend for extra virgin olive oil decreases the estimate cardiovascular risk and LDL and apolipoprotein AII concentrations in postmenopausal women.

Background: Dietary supplementation with Virgin olive oil is considered cardioprotective. Decreasing LDL and apolipoprotein (apo) AII-lipoproteins is also appropriate for CHD protection and treatment. Aim: To study the effects of an 8%En dietary exchange of linoleic acid for oleic acid on serum and lipoprotein levels and serum and LDL-TBARS in postmenopausal women consuming a diet rich in fat (46%En; saturated/monounsaturated/polyunsaturated profile: 1.1/1.9/1). Experimental Design: 14 postmenopausal women (63 ± 11 years) were assigned to exchange during 28-day dietary period the culinary oil used for years consisting in a blend of olive oil plus sunflower oil (SO) for extra virgin olive oil (EVOO). SO and EVOO represented 62% of the total lipid intake. Determinations: Dietary intakes, serum Lp(a), and cholesterol, triglycerides, phospholipids, protein, apolipoproteins AI, AII, B were determined in serum and lipoproteins. Results: The dietary intervention decreased serum total cholesterol (TC), phospholipids, apo AII (all, p < 0.001) and apo B (p < 0.01). Except for triglycerides, all components of the LDL fraction decreased (at least, p < 0.05). HDL-cholesterol was not affected but HDL-phospholipids and HDL-lipids decreased (at least, p < 0.01). VLDL-apo B and VLDL-proteins decreased (all, p < 0.001). Serum Lp(a), TBARS and LDL-TBARS were not affected by the dietary exchange. The estimate of 10-year cardiovascular risk decreased (p < 0.05). Apo AII (p = 0.061) and LDL-cholesterol (p < 0.05) underwent greater modifications in normocholesterolemics, while LDL-phospholipids (p = 0.094), experienced greater alterations in hypercholesterolemics. No significant interaction was observed between dietary exchange and age (> or <65 yrs). Conclusions: 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.

Blood pressure of omnivorous and semi-vegetarian postmenopausal women and their relationship with dietary and hair concentrations of essential and toxic metals

OBJECTIVE This study aims to ascertain the relationships between mineral consumption, hair mineral content, and blood pressure. METHODS The study involved 26 postmenopausal women from enclosed religious communities, 14 were semi-vegetarians and 12 were omnivores. Mineral dietary assessment was performed using a 14-d precise weight method and Food tables. Hair mineral levels were measured by means Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-OES). Multivariable stepwise linear regression analyses were performed to find out the variables that affected most blood pressure. RESULTS In general terms, the omnivorous diet contained a significantly higher mineral content than the semi-vegetarian one. The mineral intake from both diets implied no health risk to the women studied, as their estimated daily intake (EDI) of toxic elements such as Cd and Pb was lower than their respective provisional tolerable weekly intake (PTWI) of these minerals. Hair of the semi-vegetarians contained higher amounts of Al (p < 0.01), Ba (p < 0.01), K (p < 0.001), Na (p < 0.001), Pb (p < 0.001) and Mn (p < 0.01) but lower levels of Ca (p < 0.05) and Zn (p < 0.05) than that of their omnivorous counterparts. The omnivores presented significantly higher systolic (p < 0.01) and diastolic (p < 0.05) pressures than the semi-vegetarians. Levels of hair Co (R² = 0.328; p = 0.032) and hair K (R² = 0.409; p = 0.014)) were explicative for systolic and diastolic blood pressure, respectively. CONCLUSION Several dietary mineral and hair contents were higher in semi-vegetarian women suggesting that the hair is an important mineral excretion via contributing to maintain blood pressure at low levels.

Nutritional assessment, health markers and lipoprotein profile in postmenopausal women belonging to a closed community

Objective: To assess the dietary characteristics of a closed community and their relationship with several health markers and lipid and lipoprotein values in postmenopausal women.Design: Energy and nutrient intake, serum lipids, lipoproteins, antioxidants, peroxides and low-density lipoprotein (LDL) peroxides in addition to several health markers were measured in a closed, postmenopausal female community consuming a diet without meat, meat products and alcoholic beverages.Setting: Departamento de Nutrición and Sección Departamental de Química Analítica and Escuela de Especialización de Análisis Clínicos, Universidad Complutense de Madrid, Spain and Lerma, Burgos, Spain.Results: Cereals, vegetables, legumes and fruit, together with milk and eggs, constituted the most important ingredients of the diet consumed. Dietary carbohydrates contributed 42%en and lipids 46.4%en. The SFA/MUFA/PUFA ratio was 1/2/1 and the n-3/n-6 ratio 0.05 (SFA=saturated fatty acids, MUFA=monounsaturated fatty acids, PUFA=polyunsaturated fatty acids). The study community diet was monotonous and made for possible deficiencies of iron, magnesium, zinc, vitamin B6 and vitamin D, in variable proportions. Routine biochemical and haematological normality markers indicate that only one woman presented hyperglycaemia and hyperuricaemia. Two women had haemoglobin levels <12 g/dl, but their mean corpuscular volume or mean corpuscular haemoglobin was normal. The prevalence of high cholesterol values (>6.21 mmol/l) was 42.8%, while that of high LDL-cholesterol levels (>3.88 mmol/l) was 35.7%, but none of the women displayed levels of high-density lipoprotein (HDL)-cholesterol <1.16 mmol/l, triglycerides >1.2 mmol/l or an LDL-cholesterol/HDL-cholesterol ratio>3. Only one woman had apolipoprotein (Apo) B levels >1.5 g/l, while most of the women presented Apo B values <1.2 g/l and an ApoA-1/ApoB ratio <1.1. Plasma and LDL-peroxide levels, together with the tocopherol and carotene intakes, suggest a good antioxidant status in this population.Conclusions: The diet of the study group seems compatible with a healthy life-profile and permits a more-than-acceptable degree of cardiovascular disease protection. However, the consumption of certain nutrients should be improved.Sponsorship: This study was supported by a Danone-Universidad Complutense de Madrid grant. Project PR248/01-10161.