Relationship of dietary fat and serum cholesterol ester and phospholipid fatty acids to markers of insulin resistance in men and women with a range of glucose tolerance

High-fat diets are associated with insulin resistance, however, this effect may vary depending on the type of fat consumed. The purpose of this study was to determine the relationship between intakes of specific dietary fatty acids (assessed by 3-day diet records and fatty acid composition of serum cholesterol esters [CEs] and phospholipids [PLs]) and glucose and insulin concentrations during an oral glucose tolerance test (OGTT). Nineteen men and 19 women completed the study. Nine subjects had type 2 diabetes or impaired glucose tolerance. Fasting insulin correlated with reported intakes of total fat (r = .50, P < .01), monounsaturated fat (r = .44, P < .01), and saturated fat (r = .49, P < .01), but not with trans fatty acid intake (r = .11, not significant [NS]). Fasting glucose also correlated with total (r = .39, P < .05) and monounsaturated fat intakes (r = .37, P < .05). In multivariate analysis, both total and saturated fat intake were strong single predictors of fasting insulin (R2 approximately .25), and a model combining dietary and anthropometric measures accounted for 47% of the variance in fasting insulin. Significant relationships were observed between fasting insulin and the serum CE enrichments of myristic (C14:0), palmitoleic (C16:1), and dihomo-gamma-linolenic (C20:3n-6) acids. In multivariate analysis, a model containing CE 14:0 and percent body fat explained 45% of the variance in fasting insulin, and C14:0 and age explained 30% of the variance in fasting glucose. PL C20:3n-6 explained 30% of the variance in fasting insulin, and a model including PL C18:1n-11 cis, C20:3n-6, age and body fat had an R2 of .58. In conclusion, self-reported intake of saturated and monounsaturated fats, but not trans fatty acids, are associated with markers of insulin resistance. Furthermore, enhancement of dihomo-gamma-linolenic and myristic acids in serum CE and PL, presumably markers for dietary intake, predicted insulin resistance.     

Diet as a risk factor for the development of ulcerative colitis

OBJECTIVE: Dietary factors have been considered as a possible risk factor for ulcerative colitis (UC). However, available data are inconsistent. The aim of the present study was to evaluate the etiological role of dietary factors in the development of UC. METHODS: Recently diagnosed (<6 Months) UC patients (n = 43) and age- and gender-matched population controls (n = 43) were studied in a case-control design. The crosscheck dietary history method was used to assess dietary intake of 5 yr before the study. Adipose tissue fatty acid composition was used as a biomarker of long-term fat intake. Conditional logistic regression-derived odds ratios (OR), and 95% confidence intervals (CI) were used for statistical analysis. Dietary intake ORs were adjusted for energy intake. RESULTS: High intakes of monounsaturated fat (OR: 33.9 [95% CI 2.6-443.1]), polyunsaturated fat (OR: 5.1 [95% CI 1.0-26.7]), and vitamin B6 (OR: 6.9 [95% CI 1.6-30.7]) were associated with an increased risk to develop UC. No other significant associations were found with UC risk. CONCLUSIONS: High intakes of mono- and polyunsaturated fat and vitamin B6 may enhance the risk of developing UC. Whether this observation is a true risk factor in the development of UC or rather a reflection of a certain dietary lifestyle needs to be investigated.     

Leptin and adiponectin levels in middle-aged postmenopausal women: associations with lifestyle habits, hormones, and inflammatory markers--a cross-sectional study

To investigate the relationships between blood levels of leptin or adiponectin and lifestyle habits, hormones, and inflammatory markers, we measured parameters of alcohol intake, smoking, physical activity, and blood levels of leptin, adiponectin, testosterone, estrone, estradiol, cortisol, dihydroepiandrostenedione, luteinizing hormone, thyroxin, C-reactive protein (CRP), and interleukin 6 and interleukin 2 receptor in 76 healthy middle-aged postmenopausal women. Anthropometric measures and body composition (evaluated by dual-energy x-ray absorptiometry) and lipid profiles were also assessed. By simple regression, leptin correlated positively with fat and lean masses, glucose, triglycerides, low-density lipoprotein cholesterol, and total cholesterol, and negatively with high-density lipoprotein cholesterol. Adioponectin correlated negatively with fat and lean masses and low-density lipoprotein cholesterol, and positively with high-density lipoprotein cholesterol. Leptin concentration was correlated inversely with adiponectin (r = -0.26, P < .05) and positively with CRP (r = 0.56, P < .01). Adiponectin concentration was negatively correlated with time since last alcoholic drink (r = -0.24, P < .05) and CRP (r = -0.27, P < .05) and positively with testosterone level (r = 0.23, P < .05). By multiple regression analysis, leptin concentration was predicted by age (P < .05), testosterone (P < .05), adiponectin (P < .05), CRP (P < .01), and interleukin 6 receptor (P < .01). Adiponectin concentration was predicted by the time since last alcoholic drink (P < .05), testosterone (P < .05), leptin (P < .05), and C-reactive protein (P = .05). Similar results were found when leptin or adiponectin concentration was adjusted for fat mass. These results suggested that levels of leptin and adiponectin in middle-aged postmenopausal women are partially determined by sexual hormones and inflammatory marker levels, and both predicted one another. Moreover, adiponectin level may be modulated by alcohol intake.     

Nutrient intake, blood pressure, serum and urinary prostaglandins and serum thromboxane B2 in a controlled trial with a lacto-ovo-vegetarian diet

Fifty-nine healthy omnivores volunteered for a randomized crossover trial with a lacto-ovo-vegetarian (L-O-V) diet. Twenty-one 1-day diet records were kept throughout the project as a means of assessing food and nutrient intakes, and samples of serum and urine were assayed to evaluate change in prostanoid metabolism. While on the L-O-V diet subjects ate more vegetable protein, wholegrain cereals, polyunsaturated oils, fruits and vegetables, and avoided eating meat, fish or poultry. The L-O-V diet contained significantly more polyunsaturated fatty acids, fibre, vitamin C, vitamin E, magnesium, calcium and potassium, and less total protein, saturated fat, monounsaturated fat and vitamin B12 than the control omnivore diet. Changes in nutrient intakes were subjected to principal components analysis to identify dimensions of change in nutrient intakes. Three Factors accounted for 83% of the total variation in dietary intake. Blood pressure changes were significantly and negatively (F = 17.4, P less than 0.001 for systolic; F = 6.09, P = 0.02 for diastolic pressure) related to individual scores for only one Factor--that representing an increase in intake of polyunsaturated fat, fibre, vitamin C, vitamin E, calcium and magnesium, and a fall in intake of protein and vitamin B12. Blood pressure changes were unrelated to change in body weight or sodium intake. Serum and urinary prostanoids were not affected by eating the L-O-V diet.     

Dietary fat and heart failure: moving from lipotoxicity to lipoprotection

There is growing evidence suggesting that dietary fat intake affects the development and progression of heart failure. Studies in rodents show that in the absence of obesity, replacing refined carbohydrate with fat can attenuate or prevent ventricular expansion and contractile dysfunction in response to hypertension, infarction, or genetic cardiomyopathy. Relatively low intake of n-3 polyunsaturated fatty acids from marine sources alters cardiac membrane phospholipid fatty acid composition, decreases the onset of new heart failure, and slows the progression of established heart failure. This effect is associated with decreased inflammation and improved resistance to mitochondrial permeability transition. High intake of saturated, monounsaturated, or n-6 polyunsaturated fatty acids has also shown beneficial effects in rodent studies. The underlying mechanisms are complex, and a more thorough understanding is needed of the effects on cardiac phospholipids, lipid metabolites, and metabolic flux in the normal and failing heart. In summary, manipulation of dietary fat intake shows promise in the prevention and treatment of heart failure. Clinical studies generally support high intake of n-3 polyunsaturated fatty acids from marine sources to prevent and treat heart failure. Additional clinical and animals studies are needed to determine the optimal diet in terms of saturated, monounsaturated, and n-6 polyunsaturated fatty acids intake for this vulnerable patient population.     

Correlations of C-reactive protein levels with anthropometric profile,percentage of body fat and lipids in healthy adolescents and young adults in urban North India

OBJECTIVE: To investigate the relationships of sub-clinical inflammation and regional and generalized obesity and lipids in adolescent and young adult Asian Indians in north India. METHODS: We determined serum levels of C-reactive protein (CRP), a marker for sub-clinical inflammation, body mass index (BMI), waist circumference (WC), waist-to-hip ratio (W-HR), four skinfolds (biceps, triceps, subscapular and suprailiac), percentage of body fat (% BF) and lipid profile in 377 healthy adolescents and young adults (331 males and 46 females, age range: 14-25 years). RESULTS: Overweight subjects (BMI>85th percentile), and subjects with high values (>85th percentile) of WC and triceps skinfold thickness had significantly higher median CRP levels (P=0.04, P=0.001 and P=0.007, respectively) as compared with subjects with lower values of the variables. Elevated levels of CRP (>2.1 mg/l) were observed in 21.8% of the overweight subjects and 24.5% of the subjects with high (>85th percentile) % BF. After adjusting for age and gender, the odds ratios (95% CI) for elevated levels of CRP were 2.3 (1.1-4.7, P=0.02) for overweight subjects, 2.6 (1.2-5.4, P=0.01) for subjects with high % BF, and 3.7 (1.7-7.9, P=0.001) for subjects with high triceps skinfold thickness. Levels of CRP correlated significantly with % BF (r=0.13, P=0.009), W-HR (r=0.11, P=0.02), biceps skinfolds (r=0.13, P=0.01) and triceps skinfolds (r=0.13, P=0.01) for males only. CONCLUSIONS: The observations of substantial prevalence of elevated CRP levels in adolescents and young adults having increased generalized and abdominal adiposity may be important for the development of metabolic syndrome and atherosclerosis in Asian Indian adults.     

Fat and fish intake and asthma in Japanese women: baseline data from the Osaka Maternal and Child Health Study.

OBJECTIVE: It remains controversial whether the intake of n-3 polyunsaturated fatty acids and fish is preventive against asthma. This cross-sectional study investigated the relationship between fat and fish intake and the prevalence of asthma using baseline data from a prospective study. DESIGN: The subjects were 1002 pregnant Japanese females. A diet history questionnaire was used to assess dietary habits. Current asthma and asthma after age 18 were defined as present if subjects had been treated with medications at some time in the previous 12 months and after reaching the age of 18, respectively. RESULTS: Fish consumption was independently associated with a decreased prevalence of asthma after age 18 and current asthma. A significant inverse relationship was observed between the ratio of n-3 to n-6 polyunsaturated fatty acid intake and the prevalence of current asthma, but not asthma after age 18. Intake of total fat, saturated, monounsaturated, n-3 polyunsaturated and n-6 polyunsaturated fatty acids, cholesterol, meat, eggs or dairy products was not evidently related to either outcome for asthma. CONCLUSION: Our results suggest that fish consumption and the high ratio of n-3 to n-6 polyunsaturated fatty acid intake may be associated with a reduced prevalence of asthma in young female Japanese adults.     

Habitual dietary intake versus glucose tolerance, insulin sensitivity and insulin secretion in postmenopausal women.

OBJECTIVE: The major aim was to study the relation between habitual dietary intake and glucose tolerance, insulin sensitivity and insulin secretion in postmenopausal women. Dietary intake was also compared between women with normal (NGT) or impaired glucose tolerance (IGT). DESIGN: Habitual dietary intake was studied using a modified diet history method, from which the energy, carbohydrate, fat and protein intake was calculated. Glucose tolerance was determined as the 2 h glucose value after a 75 g oral glucose tolerance test. Insulin sensitivity was studied with a euglycemic, hyperinsulinaemic clamp, whilst insulin secretion was measured as the acute (2-5 min) response to iv arginine (5 g) at fasting, 14 and >25 mmol L(-1) glucose. SETTING: Clinical research unit at the University Hospital in Malmo, Sweden. Subjects. A total of 74 women (mean+/-SD age 58.7+/-0.4 years). RESULTS: In the entire group, the 2 h glucose level correlated with polyunsaturated fat intake (PUFA, r = 0.41, P < 0.001), and negatively with carbohydrate intake (r = -0.23, P = 0.05). The relation between 2 h glucose and PUFA was independent of body fat content and insulin sensitivity in a multivariate model. Insulin sensitivity correlated with energy intake (r = 0.31, P = 0.007) and PUFA (r = -0.27. P = 0.022). However, these correlations were not significant after adjustment for body fat content in a multivariate model. There were no correlations between insulin secretory variables and habitual dietary intake. Of the 74 women, 60 had NGT and 14 had IGT. The NGT and IGT groups did not differ in intakes of total energy, carbohydrate or protein. The IGT women had higher intake of PUFA (P = 0.003), whilst the total, saturated and monounsaturated fat intake did not differ between the groups. CONCLUSION: Dietary parameters are not independently associated with insulin sensitivity or insulin secretion in postmenopausal women. Furthermore, dietary habits are largely similar in women with NGT and IGT, although subtle differences cannot be excluded due to the small study size. Therefore, habitual intake of total carbohydrate or total fat seems not to be the major determinant of glucose tolerance in nondiabetic Caucasian postmenopausal women.     

C-reactive protein, dietary n-3 fatty acids, and the extent of coronary artery disease.

The acute-phase reactant C-reactive protein (CRP) has emerged as an independent risk factor for coronary artery disease. Experimental and clinical studies provide evidence of anti-inflammatory effects of n-3 polyunsaturated fatty acids (PUFA) derived from fish. We have studied the effect of marine n-3 PUFA on CRP levels in 269 patients referred for coronary angiography because of clinical suspicion of coronary artery disease. All patients filled out a food questionnaire regarding fish intake. The n-3 PUFA content of granulocyte membranes was determined and the concentration of CRP in serum was measured using a highly sensitive assay. The results were related to angiographic findings. CRP was significantly higher in patients with significant coronary stenoses than in those with no significant angiographic changes (p <0.001), but the CRP levels were not associated with the number of diseased vessels. Subjects with CRP levels in the lower quartile had a significantly higher content of docosahexaenoic acid (DHA) in granulocytes than subjects with CRP levels in the upper quartile (p = 0.02), and in a multivariate linear regression analysis, DHA was independently correlated to CRP (R(2) = 0.179; p = 0.003). The inverse correlation between CRP and DHA may reflect an anti-inflammatory effect of DHA in patients with stable coronary artery disease and suggest a novel mechanism by which fish consumption may decrease the risk of coronary artery disease.     

Autoantibodies against oxidized low-density lipoprotein and cardiolipin in patients with coronary heart disease

Autoantibodies against oxidized low density lipoprotein (oxLDL) have been proposed to be independent predictors of atherosclerotic vascular disease. Because the levels of autoantibodies against oxLDL and cardiolipin might be modified by the presentation and severity of coronary heart disease (CHD), we measured their levels in patients with different manifestations of CHD (n=415, mean age 61 years, range 33 to 74 years) in a subset of the European Action on Secondary Prevention through Intervention to Reduce Events (EUROASPIRE) study. There were 109 patients with coronary artery bypass surgery, 106 patients with balloon angioplasty, 101 patients with acute myocardial infarction, and 99 patients with acute myocardial ischemia. Autoantibodies were measured by ELISA. Food records and fatty acid profiles of serum cholesteryl esters were used to evaluate dietary intake. Anti-oxLDL antibodies were significantly higher in the group with acute myocardial infarction than in other groups in men (coronary artery bypass surgery 1.91+/-1. 41, balloon angioplasty 2.11+/-2.19, acute myocardial infarction 2. 52+/-2.05, and acute myocardial ischemia 1.96+/-1.78; P=0.022, mean+/-SD) but not in women. The titers of anti-cardiolipin antibodies did not differ among the patient groups. Neither of the autoantibodies was associated with recurrent coronary events. Anti-oxLDL and anti-cardiolipin autoantibodies were not correlated with serum total cholesterol, high density lipoprotein cholesterol, or triglycerides, except that in women anti-oxLDL antibodies and triglycerides were positively correlated (r=0.225, P=0.011). In men, anti-cardiolipin antibodies were higher in the lowest quartiles of dietary intakes of vitamin E and polyunsaturated fat. Dietary intakes of vitamin E and polyunsaturated fat were correlated (r=0. 588, P<0.001). In conclusion, autoantibodies against oxLDL were associated with myocardial infarction in men. Anti-cardiolipin autoantibodies were inversely correlated with dietary intakes of vitamin E and polyunsaturated fat in men with CHD.     

Dietary intake in male and female smokers,ex-smokers,and never smokers: the INTERMAP study

This report examines dietary intakes in smokers, ex-smokers, and never smokers in INTERMAP. The 4680 participants aged 40-59 years-from 17 population samples in four countries (China, Japan, UK, USA)-provided four 24-h recalls to assess nutrient intakes and two 24-h urine collections to assess excretion of urea, sodium (Na), potassium (K), etc. Compared to never smokers, current smokers generally consumed more energy from alcohol and saturated fats (SFA), less energy from vegetable protein and carbohydrates, less dietary fibre, vitamin E, beta carotene, vitamin C, thiamine, riboflavin, folate, vitamin B6, calcium, iron, phosphorus, magnesium (Mg), and K per 1000 kcal, excreted less K and urea (marker of dietary protein), had a lower ratio of polyunsaturated fat (PFA) to SFA intake, higher Keys dietary lipid score, and higher dietary and urinary Na/K. There were few differences between smokers and never smokers for total energy intake, energy from total and animal protein, monounsaturated fats, PFA, omega 3 and omega 6 PFA, dietary cholesterol, total vitamin A, retinol, vitamin D, vitamin B12, and urinary and dietary Na. Compared to ex-smokers, smokers generally consumed less energy from vegetable protein, omega 3 PFA, carbohydrates, less dietary fibre, beta carotene, vitamin E, vitamin C, thiamine, riboflavin, folate, vitamin B6, iron, phosphorus, Mg, had lower PFA/SFA, and excreted less urea and K. In conclusion, INTERMAP results are consistent with other reports indicating that smokers have less healthful diets than nonsmokers. Public health interventions in smokers should focus not only on helping them to quit smoking but also on improving their diets to further reduce cancer and cardiovascular disease risks.     

C-reactive protein in young, apparently healthy men: associations with serum leptin, QTc interval, and high-density lipoprotein-cholesterol

To determine which anthropometric, biochemical, and cardiovascular variables are associated with serum levels of C-reactive protein (CRP) in young, apparently healthy men, a cross-sectional study of 179 male college students aged 18 to 22 years was performed. Multiple regression analysis was used to derive models for serum CRP concentrations in terms of the other variables measured. Although CRP was positively correlated with body mass index (BMI), percent fat mass, and serum leptin, correlations with BMI (r = 0.15, P =.05) and percent body fat (r = 0.16, P =.003) were not as strong as the correlation with leptin (r = 0.28, P =.0002). CRP was also associated with resting heart rate (r = 0.14, P =.05), heart-rate corrected QT (QTc) interval (r = 0.22, P =.003) and several components of the insulin resistance (IR) syndrome. CRP showed a strong and negative association with high-density lipoprotein (HDL)-cholesterol (r = -0.26, P =.0005) and a marginal and positive association with triglyceride (r = 0.14, P =.05). Although CRP was associated with fasting insulin (r = 0.15, P =.04), it was not related to serum adiponectin or IR index estimated using homeostasis model assessment (HOMA). Multiple regression analysis indicated that serum CRP was positively related to serum leptin (P =.003) and QTc interval (P =.01), and negatively correlated with HDL-cholesterol (P =.01, R(2) = 0.15). In young, apparently healthy men, serum leptin but not BMI was independently associated with serum CRP, suggesting that amount of body fat may be the most significant predictor of CRP. Although low-grade inflammation was associated with long QTc interval and low HDL-cholesterol, the mechanism underlying these associations is an important question to be addressed.     

Dietary fat type (virgin olive vs. sunflower oils) affects age-related changes in DNA double-strand-breaks, antioxidant capacity and blood lipids in rats

This study was designed to investigate the possible effect on DNA double-strand breaks, antioxidant capacity and blood lipids of feeding rats lifelong with two different dietary fat sources: virgin olive oil (rich in the monounsaturated oleic acid) or sunflower oil (rich in the polyunsaturated linoleic acid). No changes in mean or maximal lifespan were observed. Overall, aging led to increased levels of plasma cholesterol, triglycerides, phospholipids, total lipids, polyunsaturated fatty acids and DNA double-strand breaks. All these parameters were higher in animals fed on sunflower oil diet. Aging diminished total antioxidant capacity with both diets, but in a lower extension for virgin olive oil diet. A very good inverse correlation (r= -0.715; P < 0.01, for sunflower oil group and r= -0.535; P < 0.01 for virgin olive oil group) between DNA damage and total antioxidant capacity was found. These results allow to conclude that dietary fat type should be considered in studies on aging, since the intake of oils with different polyunsaturation levels directly modulates total antioxidant capacity of plasma, DNA damage to peripheral blood lymphocytes and lead to important changes at the lipid metabolism level. In the present study best results were found after intake of virgin olive oil, which suggest the possible use of that edible oil to provide a healthier aging.     

Dietary fat and cholesterol intake in young children compared with recommended levels

PURPOSE: The National Cholesterol Education Program (1991) recommended that children 2 years of age or more derive less than 30% of their daily energy intake from total fat, less than 10% from saturated fat, up to 10% from polyunsaturated fat, and 10% to 15% from monounsaturated fat, and that they consume less than 300 mg/day of cholesterol. The purpose of this study was to assess whether preadolescent children were following these dietary guidelines in 1994 and to determine the relationship of diet to obesity. METHODS: This cross-sectional study was performed in elementary schools in southeast Baltimore, Maryland. The subjects were 468 children, grades 2 through 5 (mean age, 8.9 +/- 0.8 years). The main outcome measures were a 24-hour diet record, body mass index, and skinfold thickness. RESULTS: Mean percentage of total daily energy (TDE) from fat was 31.1%; saturated fat, 11.0%; monounsaturated fat, 10%; and polyunsaturated fat, 4.9%. Mean dietary cholesterol was 199.1 mg/day. Although the means for total and saturated fat are at recommended levels, the distribution of the dietary responses indicates that 50% of the children exceeded these targets. Twenty-five percent exceeded 35% of TDE derived from fat, and 25% exceeded 13% TDE derived from saturated fat. Fifty percent of children consumed below the desired level of monounsaturated fat, and almost no children consumed the desired 10% of polyunsaturated fat. Although mean dietary cholesterol was at a desired level, 16% of the children consumed more than 300 mg/day and 10% more than 377 mg/day. The negative correlation for sum of skinfold measurements with TDE (r = -0.14; P < 0.05), suggesting that fatter children consume fewer calories than thinner children, was the only correlate among dietary components and obesity. CONCLUSION: A substantial percentage of children in the United States are still not meeting recommended levels for dietary intake of fat and cholesterol. The trend for fatter children to consume fewer daily calories suggests that obesity is not entirely a result of overconsumption.     

Relationship of plasma polyunsaturated fatty acids to circulating inflammatory markers

AIMS: Persons with high intake of polyunsaturated fatty acids (PUFAs) have lower cardiovascular morbidity and mortality. The protective effect of PUFAs is mediated by multiple mechanisms, including their antiinflammatory properties. The association of physiological PUFA levels with pro- and antiinflammatory markers has not been established. METHODS AND RESULTS: In 1123 persons (aged 20-98 yr), we examined the relationship between relative concentration of fatty acids in fasting plasma and level of inflammatory markers. Adjusting for age, sex, and major confounders, lower arachidonic and docosahexaenoic acids were associated with significantly higher IL-6 and IL-1ra and significantly lower TGFbeta. Lower alpha-linolenic acid was associated with higher C-reactive protein and IL-1ra, and lower eicosapentaenoic acid was associated with higher IL-6 and lower TGFbeta. Lower docosahexaenoic acid was strongly associated with lower IL-10. Total n-3 fatty acids were associated with lower IL-6 (P = 0.005), IL-1ra (P = 0.004), and TNFalpha (P = 0.040) and higher soluble IL-6r (P < 0.001), IL-10 (P = 0.024), and TGFbeta (P = 0.0012). Lower n-6 fatty acid levels were significantly associated with higher IL-1ra (P = 0.026) and lower TGFbeta (P = 0.014). The n-6 to n-3 ratio was a strong, negative correlate of IL-10. Findings were similar in participants free of cardiovascular diseases and after excluding lipids from covariates. CONCLUSIONS: In this community-based sample, PUFAs, and especially total n-3 fatty acids, were independently associated with lower levels of proinflammatory markers (IL-6, IL-1ra, TNFalpha, C-reactive protein) and higher levels of antiinflammatory markers (soluble IL-6r, IL-10, TGFbeta) independent of confounders. Our findings support the notion that n-3 fatty acids may be beneficial in patients affected by diseases characterized by active inflammation.     

Determinants of total serum carotene concentrations in institutionalized elderly

The current analysis was designed to examine further the association between total serum carotenoids and a series of preselected variables (dietary intakes, anthropometric parameters, serum cholesterol, vitamin A, transport proteins, and others) using 85 elderly patients. Simple correlation between serum carotene and carotene intake, as estimated by a three-day weighed method, was 0.19 (P = 0.08), which was substantially increased (r = 0.29, P = 0.01) after adjustments for a selected set of variables. Standardized coefficients of multivariate regression indicated that the most important predictors of serum carotene were serum cholesterol (beta = 0.38), total serum proteins (beta = -0.35), and sex (beta = 0.34), followed by carotene intake (beta = 0.28) and midarm circumference (beta = 0.20). These variables accounted for 46% of the variance. Results suggest that serum carotene may be related to protein-energy status in hospitalized elderly, but further investigation should be directed to serum carotene in undernourished elderly. Nevertheless, total serum proteins could be an important factor in any attempt to correlate carotene intake and blood concentration.     

Circulating interleukin 6 levels, blood pressure, and insulin sensitivity in apparently healthy men and women

There is increasing evidence that systemic inflammation and insulin resistance constitute interrelated events that contribute to atherosclerosis. We studied the effect of the association between circulating interleukin 6 (IL-6) levels, one of the major mediators of inflammation, and C-reactive protein on insulin resistance and blood pressure in 228 healthy volunteers. The plasma IL-6 concentration was significantly and similarly associated with systolic (SBP) and diastolic (DBP) blood pressure, fasting insulin, and the fasting insulin resistance index (FIRI) in all subjects. When smokers were excluded from the analysis, plasma IL-6 levels correlated with percent fat mass (r = 0.19; P = 0.02), absolute fat mass (r = 0.17; P = 0.03), SBP, DBP, fasting insulin levels, and FIRI. The latter associations persisted after controlling for body mass index (r = 0.15 and r = 0.19; P = 0.02 and P: = 0.0004 for SBP and DBP, respectively; r = 0.24 and r = 0.19, P = 0.004 and P = 0.03, for fasting insulin and FIRI, respectively). Gender and smoking status significantly influenced the results. Although IL-6 levels were significantly associated with fasting insulin and FIRI in men, these significant correlations were not observed in women. Conversely, although IL-6 levels were significantly associated with SBP and DBP in women, these coefficients were not statistically significant in men. All of these associations were lost among smokers and remained significant in nonsmokers. As IL-6 is the major mediator of the acute phase response by hepatocytes and induces the synthesis of C-reactive protein (CRP), we also controlled for the latter. Serum CRP levels correlated significantly with IL-6 in all the subjects, but mainly in nonsmokers and men. Of note was that this significant relationship was lost among smokers. CRP was associated with fasting insulin (r = 0.28; P < 0.0001) and FIRI (r = 0.25; P < 0.0001), but not with SBP or DBP (P = NS), in all subjects. Unlike IL-6, the associations between CRP and these parameters were similar in men and women and in smokers and nonsmokers. For insulin and FIRI they were stronger in women and in nonsmokers. CPR significantly correlated with the WHR only in men (r = 0.22; P = 0.01). Using multiple linear regression in a stepwise manner to predict circulating IL-6 levels, smoking status (P = 0.0059) and FIRI (P = 0.03), but not fat mass or SBP, independently contributed to 11% of its variance in men. When CRP was introduced into the model, the latter (P < 0.0001) and smoking status (P = 0.02), but not FIRI, fat mass, or SBP, contributed to 33% of the variance in IL-6 levels. In women, only SBP (P = 0.04) contributed to 5% of its variance. When CRP was introduced into the model, again only SBP (P = 0.01) contributed to 10% of the variance in IL-6 levels. In 25 of these subjects, insulin sensitivity was determined using the frequently sampled iv glucose tolerance test with minimal model analysis, and circulating IL-6 levels were strongly associated with the insulin sensitivity index (r = -0.65; P < 0.0001). Again, this relationship was even stronger in men (r = -0.75; P < 0.001) and was not significant in women (r = -0.26; P = NS). In all of these subjects, only insulin sensitivity (P = 0.0037), not fat mass, contributed to 21% of the variance of IL-6 levels in a multiple linear regression analysis. In summary, circulating IL-6 levels, by inducing either hypertension in women or insulin resistance in men, constitute a significant proatherogenic cytokine. The mechanisms of these associations should be further investigated.     

Beneficial effects of increasing monounsaturated fat intake in adolescents with type 1 diabetes

This study aimed to increase the monounsaturated fat content in the diet of outpatient adolescents with type 1 diabetes and to examine the metabolic effects after 12 weeks. Twenty-three adolescents were randomly allocated to either a high monounsaturated fat diet or a control diet. Their mean age was 16.9 (S.D. 2.1) years and median HbA(1c) was 9.1% [IQR 7.9-10.4%]. Dietary targets were not reached judged by their 4-day food diaries. However, the whole study group had a significant increase in monounsaturated fat as indexed by red cell phospholipid fatty acids (RCFAs), with an increase of n-9 RCFAs from 14.9% [IQR: 14.5-21.7%] to 21.7% [IQR: 18.8-25.6%] (P=0.002). Changes in n-9 RCFAs were inversely related to changes in HbA(1c) (R(2)=0.26, P=0.02), such that a 10% increase in n-9 RCFAs corresponded to a 0.64% improvement (decrease) in HbA(1c). Changes in n-9 RCFAs were also inversely related to changes in plasma total cholesterol (R(2)=0.38, P=0.002) and plasma LDL cholesterol (R(2)=0. 21, P=0.03). These changes were not associated with changes in insulin dose, body weight or physical activity. Overall, the results demonstrate that a modest increase in the monounsaturated fat content of an adolescent diet has the potential to improve glycaemic control and lipid profile.     

Cortisol secretary pattern and glucocorticoid feedback sensitivity in women from a Mediterranean area: relationship with anthropometric characteristics, dietary intake and plasma fatty acid profile

BACKGROUND: Chronic stress is associated with a dysfunctional hypothalamic-pituitary-adrenal (HPA) axis consisting on disturbances on the cortisol response and lipid metabolism. OBJECTIVE: To evaluate the HPA axis activity in women from a Mediterranean area, comparing three different measurements: daily cortisol secretory variability, postprandial cortisol secretion and glucocorticoid feedback sensitivity. In addition, HPA axis disturbance is correlated with dietary habits and plasma fatty acid profiles. DESIGN: The participants were 41 women born during the first 6 months of 1960 and living in a Mediterranean area (Murcia, Spain). They were of normal weight, with a waist circumference of 80.5 +/- 9.3 cm. Their salivary cortisol levels, 7-day dietary record and plasma fatty acid profile were evaluated. Daily cortisol variability and postlunch cortisol secretion were recorded and a dexamethasone suppression test is performed in order to detect possible HPA disturbance. RESULTS: Both the methods used for HPA axis evaluation were positively correlated (r = 0.448, P = 0.004). Subjects with normal diurnal curves (high cortisol variability) showed significantly higher cortisol values in the morning and postprandial cortisol secretion than women with pathological curves (medium and low variability). Cortisol variability was inversely correlated with waist circumference (r = -0.312, P = 0.047), suggesting that a disturbed HPA axis response may lead to an android pattern of body fat distribution. Dietary fat and saturated fatty acid intake were lower in the high cortisol variability group, while monounsaturated fatty acid intake was higher (P < 0.05). No major differences were reported in plasma fatty acid profile. CONCLUSIONS: A disturbed HPA axis is associated with abdominal fat distribution and a higher content of fat and saturated fatty acids in the diet. Women who chose a dietary pattern closer to the Mediterranean diet, with high monounsaturated fatty acid intake, showed lower levels on HPA axis disturbance.     

Energy restriction and weight loss on very-low-fat diets reduce C-reactive protein concentrations in obese, healthy women

C-reactive protein (CRP) is an inflammatory-response protein that is a strong, independent predictor of cardiovascular mortality. CRP is positively associated with body mass index (BMI). In this study, we investigated the effects of dynamic weight loss on CRP in 83 healthy, obese women (mean BMI, 33.8+/-0.4 kg/m(2); range, 28.2 to 43.8 kg/m(2)). Subjects were placed on very-low-fat, energy-restricted diets (5700 kJ, 15% fat) for 12 weeks. Weight, waist and hip circumferences, plasma lipids, glucose, and CRP were measured at baseline and after 12 weeks. CRP was positively associated with BMI (r=0.281, P=0.01) and waist circumference (r=0.278, P=0.01) but was not related to other atherosclerosis risk factors. BMI was significantly different between groups split above or below the median for CRP (34.8+/-0.6 kg/m(2) vs 33.0+/-0.5 kg/m(2), P=0.02). After 12 weeks, weight loss was 7.9+/-0.3 kg. CRP was significantly decreased by 26% (P<0.001), and a correlation was observed between weight loss and the change in CRP (r=0.309, P=0.005). The variance in the change in CRP was partly explained by initial CRP (13.6%), energy intake (5.4%), and percentage weight loss (4.6%, P=0.001). This study confirms recent observations that BMI is associated with CRP, a marker for low-grade systemic inflammation. Furthermore, we observed that CRP was lowered in proportion to weight loss.