Changes in thyroid function with age: results from the Pizarra population-based longitudinal study.

BACKGROUND: Results of studies examining the influence of age on thyroid function and TSH levels, in the absence of thyroid disease, remain controversial. The aim of this study was to determine the course of thyroid function over 11 years in a population with normal thyroid function. METHODS: This is a population-based prospective study started in 1995-1997 (first phase), and reassessed 6 (second phase) and 11 years later (third phase). RESULTS: The TSH and FT4 in the third phase were significantly increased (p=0.001 and p=0.001, respectively), with the values being higher particularly from the age of 50 years. In those persons with a baseline TSH≥1.2 and <3 µIU/mL, the OR of having a TSH of 3-5 µIU/mL in the third phase was 6.10 (p=0.004). In those with a baseline TSH≥3 and ≤5 µIU/mL, the OR of having a TSH of 3-5 µIU/mL in the third phase was 20.8 (p<0.0001). Similar results were found for FT4. CONCLUSION: In a population free of clinical thyroid disease, TSH and FT4 values rise over the years. This increase occurs in all age groups, but depends mainly on the basal concentrations of TSH and FT4.

Hypovitaminosis D and incidence of obesity: a prospective study.

The aim of this study was to assess the relationship between obesity and vitamin D status cross-sectionally, the relationship between obesity and the incidence of hypovitaminosis D prospectively and inversely the relationship between vitamin D status and incidence of obesity in a population-based cohort study in Spain. At baseline (1996-1998), 1226 subjects were evaluated and follow-up assessments were performed in 2002-2004 and 2005-2007, participants undergoing an interview and clinical examination with an oral glucose tolerance test. At the second visit, 25-hydroxyvitamin D and intact parathyroid hormone concentrations were also measured. Prevalence of obesity at the three visits was 28.1, 36.2 and 39.5%, respectively. The prevalence of vitamin D deficiency (25-hydroxyvitamin D ≤ 20 ng/ml (≤ 50 nmol/l)) was 34.7%. Neither obesity at baseline (OR=0.98, 95% CI: 0.69-1.40, P=0.93) nor the development of obesity between baseline and the second evaluation (OR=0.80, 95% CI: 0.48-1.33, P=0.39) were significantly associated with vitamin D status. In subjects who were non-obese (BMI <30 kg/m²) at the second evaluation, 25-hydroxyvitamin D values ≤ 17 ng/ml (≤ 42.5 nmol/l) were significantly associated with an increased risk of developing obesity in the next 4 years (OR=2.35, 95% CI: 1.03-5.4, P=0.040 after diverse adjustments). We conclude that vitamin D deficiency is associated with an increased risk of developing obesity.

Incidence of obesity is lower in persons who consume olive oil.

We undertook a population-based cohort study in Pizarra (Spain). Anthropometric and nutritional variables were recorded for 613 persons. The type of fat used was determined by measurement of the fatty acids contained in cooking oil. Serum fatty acid was used as a biological marker of the type of fat consumed. Obesity incidence in persons who were not obese at baseline was greater in those who consumed sunflower oil (Group 1: 41.5 (95% CI, 25.4-67.8) cases per 1000 person-years) than in those who consumed olive oil or a mixture of oils (Group 2: 17.3 (95% CI, 11.6-25.8) cases per 1000 person-years). The risk of developing obesity over 6 years, adjusted for age, sex, physical activity, smoking, instruction level, energy intake and baseline BMI, was 2.3 (95% CI, 1.06-5.02) in group 1 compared with that in group 2. The increase in the prevalence of obesity in the free-living population is associated with the type of fatty acids in the diet.

The -30G>A polymorphism of the glucokinase gene promoter is associated with obesity in a population from southern Spain.

The aim of this study was to test the hypothesis of an association between the -30G>A polymorphism of the promoter of the glucokinase gene and the prevalence and incidence of obesity. We studied the -30G>A polymorphism of the glucokinase gene promoter in 981 persons, of whom 866 were seen again 6 years later. All the persons underwent an oral glucose-tolerance test and the BMI (weight/height(2)) was recorded. The -30G>A polymorphism of the glucokinase gene promoter was studied using RFLP-PCR. At the initial study, the probability of having a BMI > or =25 in carriers of the A allele was significantly lower than expected by chance (odds ratio (OR) = 0.63; 95% confidence interval (CI) = 0.456-0.885). In those persons with a BMI > or =30 at the first study, the probability at 6 years of losing weight (reaching a BMI < 30) was greater in carriers of the A allele (OR = 0.22; 95% CI = 0.087-0.576). The increase in weight over these 6 years, taken as a continuous variable, was significantly less only in those persons who were originally obese (P = 0.018). In conclusion, in a population from southern Spain, carriers of the A allele of the -30G>A polymorphism in the promoter of the glucokinase gene had a lower risk for obesity and the likelihood of losing weight was greater in those obese persons who had the A allele (GA or AA).

Effect of long-term administration of cross-sex hormone therapy on serum and urinary uric acid in transsexual persons.

BACKGROUND: Transsexual persons afford a very suitable model to study the effect of sex steroids on uric acid metabolism. DESIGN: This was a prospective study to evaluate the uric acid levels and fractional excretion of uric acid (FEUA) in a cohort of 69 healthy transsexual persons, 22 male-to-female transsexuals (MFTs) and 47 female-to-male transsexuals (FMTs). The subjects were studied at baseline and 1 and 2 yr after starting cross-sex hormone treatment. RESULTS: The baseline levels of uric acid were higher in the MFT group. Compared with baseline, uric acid levels had fallen significantly after 1 yr of hormone therapy in the MFT group and had risen significantly in the FMT group. The baseline FEUA was greater in the FMT group. After 2 yr of cross-sex hormone therapy, the FEUA had increased in MFTs (P = 0.001) and fallen in FMTs (P = 0.004). In MFTs, the levels of uric acid at 2 yr were lower in those who had received higher doses of estrogens (P = 0.03), and the FEUA was higher (P = 0.04). The FEUA at 2 yr was associated with both the estrogen dose (P = 0.02) and the serum levels of estradiol-17beta (P =0.03). In MFTs, a correlation was found after 2 yr of therapy between the homeostasis model assessment of insulin resistance and the serum uric acid (r = 0.59; P = 0.01). CONCLUSIONS: Serum levels of uric acid and the FEUA are altered in transsexuals as a result of cross-sex hormone therapy. The results concerning the MFT group support the hypothesis that the lower levels of uric acid in women are due to estrogen-induced increases in FEUA.

Incidence of type 2 diabetes in southern Spain (Pizarra Study).

BACKGROUND: Few European studies have used an oral glucose tolerance test (OGTT) to examine the incidence of type 2 diabetes. We determined the incidence of impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and type 2 diabetes in a population from southern Spain. MATERIAL AND METHODS: A population-based cohort study was undertaken in Pizarra, Spain. Baseline data were recorded on age, sex, weight, height, waist and hip circumferences, and diabetes status for 1051 persons, of whom 910 were free of type 2 diabetes (at-risk sample). Of these, 714 completed the 6-year follow-up study. Body mass index, waist-to-hip ratio and weight increase since baseline were calculated. The homeostasis model assessment equations were used to estimate the indices of insulin resistance and beta-cell function. Each person received an OGTT at baseline and after 6 years. RESULTS: Type 2 diabetes developed in 81 people for a total of 4253 person-years, representing an incidence of 19.1 cases per 1000 person-years (95% confidence interval, 15.3-23.6). Age and the presence of obesity, central obesity and carbohydrate metabolism disorders [IFG (cut off = 100 mg dL(-1), capillary blood glucose level), IGT or both] at baseline were significant markers for the onset of type 2 diabetes during follow-up. After adjusting for these variables, multivariate analysis showed weight increase, waist-to-hip ratio and the indices of insulin resistance and beta-cell function were significantly associated with the risk for type 2 diabetes. CONCLUSIONS: The incidence of type 2 diabetes in a population from southern Spain is high. It is probably associated with the high prevalence of obesity and weight increase in this population.

Dietary fatty acids and insulin secretion: a population-based study.

OBJECTIVE: Few epidemiological studies have examined the relationship of dietary fatty acids, especially MUFA, with the interrelation between insulin secretion and insulin resistance. We assessed the relation of dietary fatty acids with insulin secretion in a free-living population. DESIGN AND SETTING: This cross-sectional, population-based study was undertaken in Pizarra, a small town in Spain. SUBJECTS AND METHODS: Anthropometrical data were collected for 1226 persons selected randomly from the municipal census, 538 of whom (randomly chosen) were given a prospective, quantitative, 7-day nutritional questionnaire. The fatty acid composition of the serum phospholipids was used as a biological marker of the type of fat consumed. Beta-cell function (betaCFI) and insulin-resistance index (IRI) were estimated by the Homeostasis Model Assessment. RESULTS: To determine which factors influence the variability of the betaCFI, we analyzed the variance of the betaCFI according to sex, the presence of carbohydrate metabolism disorders and the different components of the diet, adjusting the models for age, body mass index (BMI) and IRI. The dietary MUFA and polyunsaturated fatty acids (PUFA) contributed to the variability of the betaCFI, whereas only the proportion of serum phospholipid MUFA, but neither the saturated fatty acids nor the PUFA accounted for part of the variability of the betaCFI in a multiple regression analysis. CONCLUSION: The results of this population-based study corroborate the results of other clinical and experimental studies suggesting a favorable relationship of MUFA with beta-cell insulin secretion. SPONSORSHIP: Fondo de Investigación Sanitaria, Junta de Andalucía and the Asociación Maimónides.

Association between MspI polymorphism of the APO AI gene and Type 2 diabetes mellitus.

AIMS: Genes of the Apo AI/CIII/AIV cluster on chromosome 11 have been related to plasma lipid patterns. The close relationship between carbohydrate metabolism and lipid metabolism warrants investigation of the association between this cluster and Type 2 diabetes mellitus. We therefore examined the possible association between polymorphisms of this cluster and Type 2 diabetes mellitus as part of a study of the prevalence of diabetes and the metabolic syndrome in southern Spain. METHODS: A total of 1224 persons were selected randomly from the town of Pizarra in the province of Malaga, southern Spain. The sample errors for the prevalence of Type 2 diabetes mellitus and the three polymorphisms studied were all < or = 4%. All subjects underwent phenotyping after an oral glucose tolerance test (75 g) (WHO 1998 criteria) and the XmnI and MspI polymorphisms of Apo AI and the SstI polymorphism of Apo CIII were genotyped. RESULTS: Those subjects with the mutated AA genotype of the MspI polymorphism (-75 G-->A) of Apo AI had a greater risk of impaired glucose tolerance [odds ratio (OR) = 1.95, CI = 1.02-3.8, P = 0.05], Type 2 diabetes mellitus, both known (OR = 7.38, CI = 1.3-39.7, P = 0.02) and unknown (OR = 3.7, CI = 1.4-9.9, P = 0.009). This risk was independent of age, sex, obesity, triglyceride level, HDL cholesterol and pattern of insulin resistance. CONCLUSIONS: Pending confirmation in prospective studies, the AA genotype of the MspI polymorphism of the Apo AI gene, within the Apo A-I/C-III/A-IV cluster, seems to be a risk factor for Type 2 diabetes mellitus.

Patterns of insulin resistance in the general population of southeast Spain.

The aim of this study was to evaluate patterns of insulin resistance in the general population. The study was cross sectional. Clinical, anthropometric, and lipid measurements were made in 1226 persons aged 18-65 years. An oral glucose tolerance test (OGTT) was performed in 1020 subjects, with insulin levels determined at baseline and after 2 h. The homeostasis model assessment insulin resistance index (HOMA IR) and HOMA beta-cell function were calculated. Compared with subjects with normal glucose tolerance, the groups with abnormal OGTT had different baseline insulinemia, 2 h post OGTT insulinemia, HOMA IR and HOMA beta-cell indices. Serum insulin levels at baseline and 2 h after OGTT showed a characteristic pattern for each category of glucose tolerance, resulting from the different insulin responses. In the subjects with normal glucose tolerance, the pattern of the relationships between both types of serum insulin levels was exactly the same, so that it was possible to determine risk groups according to the ratio of baseline serum insulin/2 h insulin. HOMA IR and HOMA beta-cell were significantly associated with the risk of impaired fasting glucose, previously unknown diabetes mellitus, and known diabetes mellitus. These results support the rationale for introducing preventive measures against insulin resistance in the general population.

Oleic acid from cooking oils is associated with lower insulin resistance in the general population (Pizarra study).

AIM: To evaluate the relation between type of dietary fatty acid and degree of insulin resistance. DESIGN: A cross-sectional study. METHODS: Anthropometrical data were measured in 538 subjects, aged 18-65 Years, selected randomly from the municipal census of Pizarra (Spain). An oral glucose tolerance test (OGTT) was given to all subjects and measurements were made of glycemia, insulinemia and the proportion of fatty acids in plasma phospholipids. Insulin resistance (IR) was estimated by homeostasis model assessment. Samples of cooking oil being used were obtained from the kitchens. The strength of association between variables was measured by calculating the odds ratio (OR) from logistic models, and the relationships were measured by linear correlation coefficients. RESULTS: Insulin resistance was significantly less in people who used olive oil compared with those who used sunflower oil or a mixture. Statistical significance remained in the group of people with normal OGTT after adjusting for obesity. In the whole sample, IR correlated negatively with the concentration of oleic acid (r=-0.11; P=0.02) and positively with that of linoleic acid (r=0.10; P=0.02) from the cooking oil. In subjects with normal OGTT, IR correlated negatively with oleic acid from cooking oil (r=-0.17; P=0.004) and from plasma phospholipids (r=-0.11; P=0.01) and positively with the concentration of linoleic acid in cooking oil (r=0.18; P=0.004) and plasma phospholipids (r=0.12; P=0.005). The risk (OR) of having raised IR was significantly lower in people who consumed olive oil, either alone (OR=0.50) or mixed (OR=0.52) compared with those who consumed only sunflower oil. CONCLUSION: There is an association between the intake of oleic acid, the composition of oleic acid in plasma phospholipids and peripheral insulin action.

The auditory threshold in a school-age population is related to iodine intake and thyroid function.

The aim of this study was to determine the relationship between auditory capacity and urinary iodine, taking into account thyroid volume and function, in a population of school-age children. Audiometry was carried out in 150 children (ages 6-14 years), together with measurements of thyroid volume, thyrotropin (TSH), free T3, free T4, thyroglobulin, antiperoxidase and anti-TSH receptor antibodies, as well as iodine in a casual urine sample. Children with a TSH >5 microU/mL were excluded from the study. In the children with palpable goiter, there was an inverse relation between the auditory threshold at all frequencies and ioduria. Children with thyroglobulin values >10 ng/mL had a higher auditory threshold at all frequencies. In the children with palpable goiter and ioduria <100 microg/L, the levels of thyroglobulin and ioduria and the age accounted for 75% of the decibel (dB) variance at 2000 (Hertz), with similar results at other frequencies. The children with a thyroid sized at the >95th percentile had an odds ratio of 3.86 (95% confidence interval: 2.59-5.10) of having a threshold >20 dB. The results warn that iodine prophylaxis is needed to prevent not only goiter but also other iodine-deficiency disorders, such as involvement of the auditory threshold in school-age children.

Incidencia de amputaciones de extremidades inferiores en la población con diabetes mellitus de Málaga (1996-1997)

Objetivo. Conocer la frecuencia de amputaciones de miembros inferiores (AMI) para el diseño de un programa preventivo de AMI en personas con diabetes mellitus (DM).Diseño. Estudio observacional, retrospectivo.Emplazamiento. Estudio poblacional en Málaga y provincia. Pacientes. Se revisaron las historias clínicas de todas las personas con AMI de hospitales públicos o concertados de la provincia de Málaga entre el 1 de enero de 1996 y el 31 de diciembre de 1997. Se excluyeron las AMI traumáticas o tumorales. Se calculó la incidencia acumulada, el riesgo relativo (RR) de AMI y la tasa de mortalidad en personas con DM.Resultados. Se realizaron 449 AMI durante el período estudiado, 316 (70,3 por ciento) en personas con DM y 133 (29,6 por ciento) en población sin DM. La incidencia de AMI por 100.000 personas y año fue de 6,3 (IC, 4,7-7,8) en población sin DM y de 136,1 (IC, 114,9-157,3) en personas con DM. El RR de AMI fue 21,6 (IC, 17,6-26,4) para la población con DM, con diferencias entre varones y mujeres (16,8 frente a 36,1, respectivamente). La edad media de AMI fue significativamente mayor (p < 0,05) para la población con DM (70,0 ñ 10,2 frente a 68,9 ñ 15,9 años, respectivamente). Las AMI mayores fueron más numerosas tanto en mujeres como en varones en los 2 grupos estudiados. La tasa de mortalidad y las complicaciones, así como la estancia media hospitalaria, fueron mayores en la población con DM.Conclusiones. Este estudio confirma el mayor riesgo de AMI en personas con DM. La incidencia de AMI en este estudio fue menor que la de países del norte de Europa, Estados Unidos y Australia, y mayor que la publicada anteriormente en España (AU)

Varying incorporation of fatty acids into phospholipids from muscle, adipose and pancreatic exocrine tissues and thymocytes in adult rats fed with diets rich in different fatty acids.

Despite numerous studies, the importance which the tissue or the composition of the diet may have in the biological distribution of each fatty acid is not well known. To determine the importance of tissue origin and dietary fatty acids in the fatty acid composition of cell phospholipids, 54 male adult rats were fed isocaloric diets for one month varying only in their fatty acid compositions. The fat component of the six experimental groups was derived from olive oil, sunflower oil, fish oil, soybean oil, palmitic acid, or 82% palmitic acid plus 18% soybean oil, supplying the essential fatty acid. The fatty acid composition of phospholipids from thymocytes, pancreatic exocrine, muscle and adipose tissues was studied by gas-chromatography. The tissue of origin was a more important source of variation than diet in the fatty acid content of the cell phospholipids except for palmitic acid (16:0), eicosapentaenoic acid (20:5 n-3), and docosahexaenoic acid (22:6 n-3). This study points out the complexity of the interrelations between different families of fatty acids and of the specificity of each tissue to changes in the composition of dietary fatty acids, as well as the inconvenience of speaking from the dietary point of view of groups of fatty acid families based on the position of the double bond, since their individual behaviour, including saturated fatty acids, is very different in the face of dietary manipulation. The study also highlights the different behaviour of each of the fatty acids in relation to the others in the diet in each of the tissues, a circumstance which should be taken into account when evaluating the biological effects in both epidemiological and experimental studies.

Serum leptin and habitual fatty acid dietary intake in patients with type 1 diabetes mellitus.

OBJECTIVE: To study the contribution of a normal intake of nutrients to the variability of serum leptin concentrations in persons with type 1 diabetes mellitus. DESIGN: We studied the relation between serum leptin and nutrient intake in a cross-sectional study. METHODS: Serum leptin measured by radioimmunoassay, nutritional data determined by a self-administered 7-day nutritional questionnaire, and the fatty acid composition of the serum phospholipids (measured by thin layer chromatography and gas chromatography) were determined in 60 patients with type 1 diabetes mellitus. Correlation and regression analyses were performed between serum leptin and dietary fatty acids and serum phospholipid fatty acids. RESULTS: In the prediction models for the concentrations of serum leptin in men with type 1 diabetes mellitus, the dietary fatty acids displaced the anthropometric variables, and were independent of the serum testosterone concentrations. This fact remained when the prediction was made on the basis of indirect markers of the intake, such as the serum phospholipid fatty acids. In the women, the fatty acids from the diet or from the serum phospholipids also partly explained the variation in serum leptin, although not displacing the anthropometric variables. CONCLUSIONS: Our data suggest that, in non-experimental conditions, the concentrations of serum leptin in men with type 1 diabetes mellitus and, to a lesser extent, those in women with diabetes, may be influenced by the composition of the habitual diet, especially the type of dietary fat.

[Incidence of amputaciones of the lower extremities in the population with diabetes mellitus in Málaga (1996-1997)]. / Incidencia de amputaciones de extremidades inferiores en la población con diabetes mellitus de Málaga (1996-1997).

OBJECTIVE: To find the frequency of amputations of lower limbs (ALL) with the aim of designing a programme to prevent ALL in people with diabetes mellitus (DM). DESIGN: Retrospective observation study. SETTING: Population study in Malaga and its province. PATIENTS: The clinical records of everyone with ALL in public or subsidized hospitals in the province of Malaga between January 1 1996 and December 31 1997 were reviewed. Traumatic or tumoural ALL were excluded. Cumulative incidence, relative risk (RR) of ALL and the mortality rate of people with DM were calculated. RESULTS: 449 ALL took place during the period studied, 316 (70.3%) in people with DM and 133 (29.6%) in people not suffering DM. The incidence of ALL per 100,000 people and per year was 6.3 (CI: 4.7-7.8) in the population without DM and 136.1 (CI: 114.9-157.3) in people with DM. The RR of ALL was 21.6 (CI: 17.6-26.4) for the population with DM, with differences between men and women (16.8 vs. 36.1, respectively). Mean age of ALL was significantly greater (p < 0.05) for the population with DM (70.0 +/- 10.2 vs. 68.9 +/- 15.9 years old). Older ALL were more numerous in both women and men in the two groups studied. The mortality rate, complications and mean stay in hospital were greater in the population with DM. CONCLUSIONS: This study confirmed the greater risk of ALL run by people with DM. The incidence of ALL in this study was less than in countries of Northern Europe, the USA and Australia, but more than in any study published before in Spain.

[Factors influencing the prescription of insulin and oral antidiabetics in primary care]. / Factores que influyen en la prescripción de insulinas y antidiabéticos orales en atención primaria.

OBJECTIVES: To analyse the prescription of insulin and oral diabetic medication (ODM) in primary health care, and to evaluate which variables, depending on the prescribing doctor, work-place or population attended, explain quality and/or quantity variations in prescription. DESIGN: Crossover, observational study. SETTING: Málaga-Este Health District, Málaga. PARTICIPANTS: 21,166 prescriptions issued by 144 doctors in the Málaga-Este Health District during the first quarter of 1997 were analysed. MEASUREMENTS AND MAIN RESULTS: Insulin consumption of 10.63 defined daily doses per 1,000 inhabitants and day (DID) and ODM of 18.51 DID were calculated. No significant differences were observed in insulin or ODM prescription for sex, and few for age, job or doctors' specialty via MIR (intern) training. Working in a centre with MIR teaching and in a reformed centre were significantly associated with a greater use of insulin (p < 0.0001 and p < 0.02, respectively). Having a higher allocation of patients drawing pensions meant a greater consumption of insulin (p < 0.01) and even more of ODM (p < 0.0001). The population allocated being older was associated with greater consumption of ODM without any changes in insulin prescription. CONCLUSIONS: The personal features of doctors working in primary care affect very little the quantity and quality of insulin and ODM prescription. The characteristics of the work-place (reformed centre and centre entitled to teach) and the population attended (older and drawing a pension) are the main factors conditioning the amount of prescription of insulin and ODM, respectively. Nevertheless, in all cases ODM prescription quality is low.

Lipid, protein, and calorie content of different Atlantic and Mediterranean fish, shellfish, and molluscs commonly eaten in the south of Spain.

We undertook a systematic evaluation of the lipid, protein, calorie, and fatty acid composition in 35 species of fish, shellfish and molluscs commonly consumed throughout the four seasons of the year in Andalusia, Spain. Using a portion of muscle tissue the following were measured in each study unit: total lipids (extraction using Folch's method and gravimetry), protein concentration (Kjehldal's method), total calories (direct calorimetry), and composition of fatty acids (gas chromatography). The lipid, protein, and different fatty acid concentrations found are presented in table form. There was a high degree of inter-species variability in the concentration of lipids and the various fatty acids. There was also a high degree of intra-species seasonal variability in some cases. The relative proportion of fatty acids was not independent of the total concentration of lipids, independently of the season studied. This systematic study of a large group of species shows that the cataloguing of fish as 'white' or 'blue' depends especially on the time of year they are captured. For example, in spring the mackerel (Scomber scombrus), a fish considered traditionally to be 'blue' (fatty), has the same lipid concentration as the dover sole (Solea vulgaris), commonly considered to be 'white' (little fat), and the sea pike (Merluccius merluccius) has a higher lipid concentration in autumn than the jack mackerel (Trachurus trachurus). Even greater differences existed when the fish were classified according to their richness in n-3 fatty acids. These differences in the total lipid concentration and the composition of fatty acids, as well as the inter-relations between them, may, under certain circumstances, be important for the calculation of dietary calories and nutritional values, and may explain the differences found between the various tables of food composition, as well as the divergent results in epidemiological studies on the association between fish in diets and various diseases, such as diabetes or ischaemic cardiopathy.

[Fat, protein and caloric content of different fish, seafood and mollusks, Atlantic and Mediterranean habitually consumed in the south of Spain]. / Contenido graso, proteico y calórico de diferentes pescados, mariscos y moluscos, atlánticos y mediterráneos habitualmente consumidos en el Sur de España.

OBJECTIVE: To evaluate in a systematic manner, the fat, protein, caloric, and fatty acids contents of 35 species of fish, seafood and mollusks, usually consumed in Andalucía (Spain). MATERIALS AND METHODS: 35 different species, representative of those usually consumed in Andalucía in the course of the four seasons of the year, are studied. In all units of the study, in a portion of the muscle tissue, measurements were taken to evaluate the total fat (extraction by the Folch method and by gravimetry), protein concentration (Kjehldal method), total calories (gas chromatography). RESULTS: A table shows the concentration of fat, protein and different fatty acids found in the studied species. There is a great interspecies variability in the fat concentration and in that of the different fatty acids. In the same way there is a great interspecies seasonal variety for some of those studied. Independently of the season studied, the relative proportion of fatty acids was not independent of the total concentration of fat. DISCUSSION: From the nutritional, culinary and gastronomic point of view, in the Mediterranean area it is common to classify the fish as "white" (low fat) and "blue" (fat). However, the systematic study of a large number of species shows that the categorization of "white" or "blue" depends on the time of year in which they are captured. For example, in spring the horse-mackerel (Scomber scombrurus), a fish traditionally considered "blue" (fat), has the same fat concentration as the sole (Soles vulgaris), generally considered "white" (low fat). And the hake (Merluccius merluccius), in autumn, has a fat concentration which is greater than that of the carangoid sea-fish (Trachurus trachurus). Even greater differences can be seen if we classify the fish according to their richness in n-3 fatty acids. These differences in the total fat concentration and in the composition of fatty acids, as well as the inter-relations between both, may be important in determining the circumstances for the caloric and nutritional calculation of a diet, and may explain the differences found between the different tables of food composition, as well as the divergent results found in the epidemiological studies on the association between the fish of the diet and the different diseases such as diabetes or ischemic heart disease.