Maternal n-6 and n-3 fatty acid status during pregnancy is related to infant heart rate and heart rate variability: An exploratory study

Early life heart rate (HR) and heart rate variability (HRV) reflect autonomic system maturation. Intervention with n-3 long chain polyunsaturated fatty acids (LCPUFAs) during pregnancy favorably affects fetal HR and HRV, complementing previous observations for n-3 LCPUFA intervention during infancy. The relationship between maternal fatty acid status during pregnancy and infant HR/HRV has not previously been assessed. The aim of this study was to explore associations between maternal n-6 and n-3 fatty acid status during pregnancy and infant HR and HRV at 2 weeks, 4 months, and 6 months of age using linear regression models. Maternal n-3 fatty acids were inversely related to infant HR and positively related to HRV. Conversely, maternal n-6 fatty acids were positively related to infant HR and inversely related to HRV. These data build on existing literature evidencing a role for n-3 fatty acids in accelerating autonomic development and link n-6 fatty acids to HR/HRV.

The impact of supplemental n-3 long chain polyunsaturated fatty acids and dietary antioxidants on physical performance in postmenopausal women

OBJECTIVES

Identify relationships and evaluate effects of long chain polyunsaturated fatty acids (LCPUFA) on frailty and physical performance.

DESIGN

Randomized, double blind pilot study.

SETTING

University General Clinical Research Center.

PARTICIPANTS

126 postmenopausal women.

INTERVENTION

2 fish oil (1.2g eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) or 2 placebo (olive oil) capsules per day for 6 months. All participants received calcium and vitamin D supplements.

MEASUREMENTS

Fatty acid levels, frailty assessment, hand grip strength, 8 foot walk, body composition, medical history and co-morbidities, nutrient intake, and inflammatory biomarkers taken at baseline and 6 months.

RESULTS

At baseline, those with greater red blood cell (RBC) DHA and DHA/arachidonic acid (AA) presented with less frailty (r = -0.242, p=0.007 and r = -0.254, p=0.004, respectively). Fish oil supplementation resulted in higher RBC DHA and lower AA compared to baseline and placebo (p<0.001) and an improvement in walking speed compared to placebo (3.0±16 vs. -3.5±14, p=0.038). A linear regression model included age, antioxidant intake (selenium and vitamin C), osteoarthritis, frailty phenotype, and tumor necrosis factor alpha (TNFα). The model explained 13.6% of the variance in the change in walking speed. Change in DHA/AA (p=0.01) and TNFα (p=0.039), and selenium intake (p=0.031) had the greatest contribution to change in walking speed.

CONCLUSION

Physical performance, measured by change in walking speed, was significantly affected by fish oil supplementation. Dietary intake of antioxidants (selenium and vitamin C) and changes in TNFα also contributed to change in walking speed suggesting LCPUFA may interact with antioxidants and inflammatory response to impact physical performance.

Consumption of lipophilic contaminants in human milk by infants: quantities are usually incorrect

We evaluated several reports on the detection of nitromusks (artificial perfumes) in human milk. The nitromusks found were separated by gas-liquid chromatography and identified by mass spectrometry. However, the quantities reported as being consumed by infants were often questionable (Jensen, 1995). The investigators did not always a) obtain a representative samples of milk, b) extract and quantify the fat by a recognized, accurate method, or c) determine the amount of milk, hence fat, consumed by the infant. Some investigators gave almost no data on the milk, except to say that a sample was obtained. Reports on some other contaminants in human milk were similarly deficient. We have published a description of recommended extraction procedures in a paper presenting a detailed protocol for the processing of milk so as to determine the actual amounts of lipophilic contaminants ingested by the nursing infant (Jensen et al. 1997).

Parenteral infusion of a lactating woman with intralipid: changes in milk and plasma fatty acids

A nursing woman afflicted with short bowel syndrome received parenteral infusions of Intralipid. In the morning following 2 nights of infusion, samples of milk and blood were taken; additional samples were taken the morning after 1 and 2 nights of no infusion. The fatty acid composition of these samples was determined by gas chromatography. The Intralipid infusion contained 51.5% linoleic acid (C18:2). The C18:2 content of the milk was highest (14%) after each infusion and dropped to about 10% on days 1 and 2. Inverse changes were seen in stearic acid (C18:0). The C18:2 content of the plasma showed little change, remaining at about 23%. These results provide further direct evidence that the composition of milk fatty acids can be influenced by changes in the composition of external sources of fatty acids to the lactating mother.

Fetal erythrocyte phospholipid polyunsaturated fatty acids are altered in pregnancy complicated with gestational diabetes mellitus

Insulin resistance and altered maternal metabolism in gestational diabetes mellitus (GDM) may impair fetal arachidonic acid (AA) and docosahexaenoic acid (DHA) status. The objectives were to test the hypothesis that fetal polyunsaturated fatty acids would be altered with GDM and identify factors related to fetal phospholipid (PL) AA and DHA. Maternal and cord vein erythrocyte PL fatty acids were determined in GDM (n = 13) and healthy pregnant women (controls, n = 12). Cord vein erythrocyte PL AA and DHA concentrations were significantly lower in GDM vs. controls. Maternal blood hemoglobin A1C was inversely correlated to fetal erythrocyte PL DHA and AA in controls and GDM (n = 25). Pregravid body mass index was negatively associated with fetal PL DHA. The data support the hypothesis that there is impairment in fetal accretion of DHA and AA in GDM.

Distribution of serum apolipoproteins A-I and B and lipoprotein(a) in European elderly. The SENECA study

The purpose of this study is to describe sex and geographic differences in apolipoproteins (apo) A-I and B and lipoprotein(a) [Lp(a)] concentrations in elderly Europeans. Subjects were 2164 elderly participants of the SENECA study from different regions of Europe. Sera for apo A-I, apo B, and Lp(a) measurement were available for 1703 individuals. In men, mean values ranged from 1.38 to 1.79 g/l for apo A-I, 1.03-1.36 g/l for apo B, and 0.26-0.67 g/l for Lp(a). In women, mean values ranged from 1.54 to 1.98, 1.20-1.51, and 0.26-0.68 g/l for apo A-I, apo B, and Lp(a), respectively. A comparison of northern (Norway, Denmark, Netherlands), middle (France, Switzerland), and southern (Portugal, Spain, Italy, Greece) communities showed a less atherogenic profile in the south, including lower LDL cholesterol, apo B, TC/HDL cholesterol ratio, and apoB/apo A-I ratio. Men, but not women, also had significantly higher HDL cholesterol and apo A-I concentrations in the South. Paradoxically, Lp(a) concentrations were generally high among all elderly and were significantly higher in the southern communities. These data show that the elderly in Europe are very heterogeneous with respect to plasma lipoproteins, including apo A-I, apo B, and Lp(a).

Dietary cholesterol increases the susceptibility of low density lipoprotein to oxidative modification

Evidence suggests that oxidative modification of low density lipoprotein (LDL) occurs in vivo, increasing the atherogenecity of the particle. A total of 13 subjects (age range 46-78 years) with an LDL cholesterol concentration >3.36 mmol/l consumed each of four diets for 32-day periods. The diets contained 30% energy as fat of which 2/3 was either corn oil or beef tallow with and without 115 mg/4.2 MJ of supplemental cholesterol in the form of cooked egg yolk. The susceptibility of LDL to oxidation was assessed during a challenge with hemin and hydrogen peroxide, and results are expressed as lag time to oxidation in minutes. Addition of moderate amounts of cholesterol to either the corn oil or beef tallow enriched diet resulted in increased susceptibility of LDL to oxidation (decreased lag time): 69+/-22 min versus 96+/-24 min in the corn oil diet with versus without supplemental cholesterol, respectively, P = 0.006; 82+/-20 min versus 96+/-26 min in the beef tallow diet with versus without supplemental cholesterol, respectively, P = 0.025. A stepwise equation indicated that as plasma oleic acid concentrations increased and/or linoleic acid concentrations decreased, lag time increased (decreased susceptibility to oxidation), whereas as dietary cholesterol concentrations increased, lag time decreased (increased susceptibility to oxidation). In conclusion, these data suggest that addition of a moderate amount of dietary cholesterol to a reduced fat diet rich in polyunsaturated or saturated fatty acids increased the in vitro susceptibility of LDL to oxidation.

Maternal plasma phospholipid polyunsaturated fatty acids in pregnancy with and without gestational diabetes mellitus: relations with maternal factors

BACKGROUND

The fatty acids arachidonic acid (AA; 20:4n-6) and docosahexaenoic acid (DHA; 22:6n-3) are essential for fetal growth and development, but their metabolism may be altered in insulin resistance.

OBJECTIVES

The objectives were to determine maternal plasma phospholipid polyunsaturated fatty acid concentrations in pregnant women receiving dietary therapy for gestational diabetes mellitus (GDM) and to identify maternal factors associated with plasma phospholipid AA and DHA concentrations in the third trimester.

DESIGN

Fasting plasma phospholipid fatty acids were determined in women with GDM (n = 15) receiving dietary therapy only and in healthy, pregnant women without GDM (control group, n = 15) at 27-30, 33-35, and 36-39 wk gestation.

RESULTS

Maternal plasma phospholipid (as % by wt of total fatty acids and mg/L) linoleic acid (18:2n-6), AA, and 22:5n-6 concentrations did not differ significantly between women with GDM and control subjects. The other n-6 long-chain polyunsaturated fatty acids (% by wt) were lower in GDM subjects than in control subjects. Plasma phospholipid (expressed as % by wt and mg/L) linolenic acid (18:3n-3) and summed precursors of DHA were lower and DHA (% by wt and mg/L), adjusted for dietary DHA intake, was 13% higher in GDM subjects than in control subjects. Maternal blood hemoglobin A1C was inversely related to plasma phospholipid AA (% by wt) (r = -0.56, P = 0.03) in control subjects and positively associated with plasma phospholipid AA (% by wt) in women with GDM (r = 0.76, P = 0.001). Pregravid body mass index was negatively associated with plasma phospholipid DHA (% by wt) in control subjects (r = -0.55, P = 0.04) and in women with GDM with a body mass index (in kg/m2) <30 (r = -0.76, P = 0.007).

CONCLUSIONS

This is the first report documenting alterations in maternal plasma phospholipid PUFAs in pregnant women receiving dietary therapy for GDM. In pregnant woman, both with and without GDM, maternal glycemic control and pregravid BMI appear to be significant predictors of plasma phospholipid AA and DHA, respectively, during the third trimester. Additionally, dietary DHA significantly affects phospholipid DHA concentrations.

Carotenoid intakes, assessed by dietary questionnaire, are associated with plasma carotenoid concentrations in an elderly population

High intakes of fruits and vegetables and of carotenoids are associated with a lower risk for a variety of chronic diseases. It is therefore important to test the validity of dietary questionnaires that assess these intakes. We compared intakes of five carotenoids, as calculated from responses to the Willett 126-item food-frequency questionnaire, with corresponding biochemical measures. Subjects included 346 women and 201 men, aged 67-93 y, in the Framingham Heart Study. Unadjusted correlations were higher among women than men as follows: alpha-carotene 0.33 and 0.18, beta-carotene, 0.36 and 0.25; beta-cryptoxanthin, 0.44 and 0.32; lycopene, 0.35 and 0.21; and lutein + zeaxanthin, 0.27 and 0.10, respectively. Adjustment for age, energy intake, body mass index (BMI, kg/m2), plasma cholesterol concentrations and smoking reduced the gender differences, respectively, to the following: alpha-carotene 0.30 and 0.28; beta-carotene, 0.34 and 0.31; beta-cryptoxanthin, 0.45 and 0.36; lycopene, 0.36 and 0.31; and lutein + zeaxanthin, 0.24 and 0.14. Plots of adjusted mean plasma carotenoid concentration by quintile of respective carotenoid intake show apparent greater responsiveness among women, compared with men, to dietary intake of alpha- and beta-carotene and beta-cryptoxanthin, but similar blood-diet relationships for lycopene and lutein + zeaxanthin. Reported daily intake of fruits and vegetables correlated most strongly with plasma beta-cryptoxanthin and beta-carotene among women and with plasma alpha- and beta-carotene among men. With the exception of lutein + zeaxanthin, this dietary questionnaire does provide reasonable rankings of carotenoid status among elderly subjects, with the strongest correlations for beta-cryptoxanthin. Appropriate adjustment of confounders is necessary to clarify these associations among men.

Varying dietary fat type of reduced-fat diets has little effect on the susceptibility of LDL to oxidative modification in moderately hypercholesterolemic subjects

The effect of the fatty acid composition of reduced-fat diets on the in vitro oxidation of LDL was examined in 14 moderately hypercholesterolemic [low density lipoprotein (LDL) > 3.36 mmol/L] postmenopausal female and male subjects (age 44-78 y). Each subject consumed each of five reduced-fat diets [30 energy percent (E%) fat, 17 E% protein and 53 E% carbohydrate] enriched in beef tallow, canola oil, corn oil, olive oil or rice bran oil (20 E%) for 32-d periods. In vitro oxidation of LDL was assessed by incubating LDL with hemin and hydrogen peroxide, and measuring the time required for the reaction to reach maximum velocity (lag time). LDL lag times were 93.2 +/- 25.8, 95.9 +/- 26.4, 104.2 +/- 32.7, 108.0 +/- 26.6 and 113.1 +/- 24.0 min for corn oil, beef tallow, rice bran oil, canola oil and olive oil periods, respectively. When the data from all dietary phases were pooled, LDL alpha-tocopherol level (r = 0.30, P = 0.01) and plasma 18:1/18:2 ratio (r = 0.22, P = 0.08) were positively related to resistance of LDL to oxidation. Differences induced by the dietary perturbations in LDL content of beta-cryptoxanthin, lutein/zeaxanthin, lycopene, alpha-carotene or beta-carotene, and LDL particle size were not related to resistance of LDL to oxidation. In conclusion, in middle-aged and elderly moderately hypercholesterolemic subjects, the consumption of reduced-fat diets enriched in animal fat or vegetable oils with a relatively wide range of fatty acid profiles did not alter the in vitro susceptibility of LDL to oxidation. The advantages of reducing the saturated fat content of the diet were reflected in lower total and LDL cholesterol levels.

Maternal and cord plasma lipid and lipoprotein concentrations in women with and without gestational diabetes mellitus. Predictors of birth weight?

OBJECTIVE

To describe lipid and lipoprotein perturbations in gestational diabetes mellitus (GDM) and to examine the potential consequences--e.g, increased birth weight and increased placental lipid transfer.

STUDY DESIGN

Maternal and cord free fatty acids (FFAs) and total, very low density lipoprotein (VLDL), low density lipoprotein (LDL), high density lipoprotein (HDL) (and maternal HDL2 and HDL3), triglyceride (TG), and cholesterol and dietary intake were determined for women with diet-treated GDM and for healthy pregnant women with normal glucose tolerance.

RESULTS

Women with GDM had higher hemoglobin A1c than controls, while body weight gain was significantly lower for women with GDM as compared to controls. Plasma and lipoprotein TG concentrations were greater for women with GDM, and although plasma FFAs were higher in women with GDM versus controls, the difference was not significant. No differences were observed between groups with respect to maternal plasma or lipoprotein cholesterol. Cord plasma and lipoprotein lipids were similar between groups; with the exception of VLDL + LDL TG, which was lower in women with GDM. In controls, there were significant correlations between maternal plasma TG and cord FFAs; maternal HDL2 cholesterol and cord plasma cholesterol; and maternal plasma TG, maternal HDL2 cholesterol, cord FFAs, and infant birth weight. In GDM, maternal plasma cholesterol and cord VLDL + LDL cholesterol correlated. There were no significant correlations between maternal or cord lipids and infant birth weight in women with GDM.

CONCLUSION

Hypertriglyceridemia, rather than hypercholesterolemia, is a feature of GDM. However, elevations in maternal plasma and lipoprotein TGs in women with GDM were not related to fetal lipid concentrations or infant birth weight.

The anticarcinogenic conjugated fatty acid, 9c, 11t-18:2, in human milk: confirmation of its presence

The concentration of the anticarcinogenic fatty acid, 9c, 11t-18:2, in human milk was determined by gas-liquid chromatography (GLC). The mean concentration of 20 samples from 5 women taken at 1, 7, 14, and 21 days was: 0.18% +/- 0.02; range, 0.14-0.28%. Identity was confirmed by GLC-mass spectrometry (MS). Conjugated isomers other than 9c, 11t-18:2 were not detected. The amounts were not changed by supplementation of the maternal diet with fish oil beginning on day 1 after the milk sample was taken.

Elevated lipoprotein lipids and gestational hormones in women with diet-treated gestational diabetes mellitus compared to healthy pregnant controls

The objective of this study was to describe plasma and lipoprotein perturbations in gestational diabetes mellitus (GDM) compared to controls, and determine if alterations in lipids are related to gestational hormones and/or glucose control. Maternal HbA1c, free fatty acids (FFA), beta-estradiol, progesterone, prolactin, and plasma, very-low-density lipoprotein (VLDL), low-density lipoprotein (LDL), high-density lipoprotein (HDL), HDL2 and HDL3 triglyceride (TG), cholesterol, and dietary intake were determined for women with diet-treated GDM and controls in a longitudinal design. Subjects (N = 25/group) were matched for age, race, and body-mass index (BMI). Women with GDM had significantly higher HbA1c than controls, although both groups were within the normal range (4%-6%). However, body weight gain was less for women with GDM. There was a trend for higher plasma FFAs at 37-38 weeks in GDM versus controls. Plasma and lipoprotein TG among the groups increased over the third trimester, and mean concentrations were greater for women with GDM. In GDM versus controls, VLDL and HDL3 TGs were higher at all times, HDL and HDL2 TGs at 33-34 and 37-38 weeks, and LDL TGs at 37-38 weeks. In VLDL, core lipids (TG + cholesterol) increased over gestation and were greater in GDM. In HDL, the TG/cholesterol ratio was greater in GDM. In GDM versus controls, plasma progesterone and prolactin were higher at all times; beta-estradiol was elevated at 37-38 weeks. HbA1c, progesterone, and prolactin correlated with all lipoprotein TG fractions. Exaggerated hypertriglyceridemia, particularly in the VLDL and HDL fractions, is a feature of GDM. The increase in VLDL TG is likely due to an increase in VLDL synthesis, whereas particle enrichment in TG is a plausible explanation for changes in HDL TG. Slight perturbations in glucose control and gestational hormones in diet-treated GDM may contribute to the observed increase in plasma and lipoprotein TG.

Plasma retinol and plasma and lipoprotein tocopherol and carotenoid concentrations in healthy elderly participants of the Framingham Heart Study

Data on plasma concentrations of tocopherols and the major carotenoids in adults aged > or = 65 y, particularly in those > 80 y, are sparse. In the current study retinol, tocopherol (alpha- and gamma-tocopherols), and carotenoid (lutein/zeaxanthin, cryptoxanthins, lycopene, and alpha- and beta-carotene) concentrations were determined in 638 subjects, 230 men (aged 75 +/- 5 y) and 408 women (76 +/- 6 y), of the Framingham Heart Study. All subjects were free of clinical evidence of cardiovascular disease and cancer. Percentile ranges were comparable with those established in younger cohorts. Moreover, women had significantly higher plasma alpha-tocopherol and plasma and lipoprotein concentrations of beta-cryptoxanthin and alpha- and beta-carotene than did men. Lycopene concentrations were inversely correlated with age and lowest among subjects > or = 80 y. Total intakes (diet+supplements) of vitamin C and vitamin E, but not dietary intakes alone, were positively associated with plasma alpha-tocopherol and inversely associated with gamma-tocopherol concentrations. In multivariate analyses, plasma cholesterol and triacylglycerol concentrations and total intake of vitamins E and C predicted 64% and 55% of the plasma alpha-tocopherol concentrations in men and women, respectively. Important predictors for the majority of carotenoids included plasma cholesterol concentration, body mass index (negative effect), and smoking status (negative effect); for lycopene concentration they included cholesterol concentration and age (negative effect). In summary, percentile ranges and lipoprotein distributions were comparable with those established in younger cohorts, suggesting that overall antioxidant status is not altered in people between the ages of 67 and 96 y.

Women with insulin-dependent diabetes mellitus (IDDM) complicated by eating disorders are at risk for exacerbated alterations in lipid metabolism

OBJECTIVE

To examine lipid parameters that are affected in women with insulin-dependent diabetes mellitus (IDDM) who engaged in disordered eating behaviours.

DESIGN

Randomized, unmatched.

SETTING

Tertiary care.

SUBJECTS

Ninety women (18-46 y) with IDDM.

INTERVENTIONS

Classification of subjects based on severity of eating disorder: clinical (n = 14), subclinical (n = 13) and control (n = 63). Blood was analysed for glycosylated haemoglobin (HbA1c) and serum for triglycerides and cholesterol. Carotenoid and tocopherol concentrations were analysed by high performance liquid chromatography (HPLC). Dietary intake was assessed by the National Cancer Institute food frequency questionnaire.

RESULTS

HbA1c was significantly increased im women demonstrating clinical and subclinical symptoms compared to control (10.4 +/- 2.6, 10.0 +/- 1.5 and 8.3 +/- 1.6%, respectively, P < 0.05). Triglycerides concentrations were significantly increased in women with subclinical eating disorders compared to controls. In women who intentionally omitted or reduced insulin, triglyceride cholesterol and HbA1c were significantly increased compared to controls. Women with IDDM and eating disorders who exhibited bulimic behaviours consumed significantly more energy, total fat and cholesterol compared to controls and women with eating disorders who were restrained eaters.

CONCLUSION

While IDDM is known to perturb lipid metabolism, these data demonstrate that eating disorders, in combination with IDDM, results in additional alterations in lipid metabolism.

Subclinical and clinical eating disorders in IDDM negatively affect metabolic control

OBJECTIVE

To characterize the relationship of subclinical and clinical eating disorders to HbA1c values in women with IDDM.

RESEARCH DESIGN AND METHODS

Ninety women with IDDM (18-46 years of age) were recruited from diabetes clinics throughout Connecticut and Massachusetts. Subjects were categorized into one of three groups according to the Diagnostic Statistical Manual of Mental Disorders (DSM-III-R) criteria for eating disorders as follows: the clinical group (n = 14), the subclinical group (partially fulfilling the diagnostic criteria; n = 13), and the control group (n = 63). Group differences in the degree of dietary restraint, binge eating, and bulimic behaviors and weight, shape, and eating concerns were assessed with the Eating Disorder Examination (EDE) and the Bulimia Test Revised (BULIT-R).

RESULTS

Women with subclinical and clinical eating disorders had clinically elevated HbA1c results and more diabetes-related complications, compared with the control subjects. The severity of bulimic behaviors, weight concerns, reduced BMI, and decreased frequency of blood glucose monitoring were associated with elevated HbA1c.

CONCLUSIONS

HbA1c may have clinical utility in the identification of eating disorder behavior in females with IDDM. Health care professionals should be aware of the potent effect of subclinical and clinical eating behaviors including insulin misuse in weight-conscious women with IDDM who have poor glycemic control.

Plasma lipoprotein(a) distribution in the Framingham Offspring Study as determined with a commercially available immunoturbidimetric assay

The purpose of our research was to evaluate a commercially available, automated, immunoturbidimetric assay for lipoprotein(a) (Lp(a)), to determine the distribution of Lp(a) in the Framingham Offspring Study population, and to determine Lp(a) levels that may be useful for assessing coronary heart disease risk. The mean between-run coefficient of variation for this assay was 5.65%. Lp(a) concentration was slightly, but significantly, higher in 1949 white women (mean +/- S.D. 214 +/- 195 mg/l, median 150 mg/l) than in 1884 white men (mean +/- S.D. 200 +/- 193 mg/l, median 130 mg/l) participating in Cycle 4 of the Framingham Offspring Study (P = 0.0015). Lp(a) values of 300 mg/l and 500 mg/l corresponded to approximately the 75th and 90th percentiles, respectively, for both men and women, and subjects with concentrations greater than or equal to 500 mg/l were more likely to have coronary heart disease than subjects with an Lp(a) concentration less than 300 mg/l (P < 0.05 for men).

Longitudinal changes in serum lipids of elderly Europeans. SENECA Investigators

OBJECTIVE

To describe the serum total cholesterol, lipoprotein cholesterol and triglyceride concentrations in elderly people from the SENECA follow-up study and report on longitudinal changes in these lipid concentrations over a four-year follow-up period.

DESIGN

Longitudinal study including baseline measurements taken in 1988/1989 which were repeated in 1993.

SUBJECTS

In 1993 lipid concentrations were assayed in blood serum collected from 1181 elderly men and women, born from 1913 to 1918 and living in twelve small towns in ten European countries and one town in the USA. 1062 of these subjects had also participated in the baseline study.

RESULTS

Mean concentrations ranged from 4.91 to 6.72 mmol/l for total cholesterol, 1.15 to 1.64 mmol/l for HDL cholesterol, 3.04 to 4.47 mmol/l for LDL cholesterol and 1.03 to 1.79 mmol/l for triglycerides. Thirty-two per cent of European men and 18% of women had plasma total cholesterol concentrations below 5.16 mmol/l; 32% of men and 56% of women had HDL cholesterol concentrations exceeding 1.42 mmol/l. Total- and HDL-cholesterol concentrations, and the HDL:total cholesterol ratio were higher in women than in men. Despite large variations between towns no clear north-south gradient was observed. Yet, lowest values for LDL cholesterol tended to be located in the south, while the highest values for LDL cholesterol showed up in the north. Comparisons between the 1989 and 1993 surveys revealed a significant decrease in total cholesterol and an increase in the HDL:total cholesterol ratio without significant variation in HDL cholesterol or triglyceride concentrations.

CONCLUSION

Though serum lipid concentrations varied widely across Europe, a marked decline in total cholesterol values along with an increase in the HDL:total cholesterol ratio occurred across the SENECA towns.

Changes in the vitamin status of elderly Europeans: plasma vitamins A, E, B-6, B-12, folic acid and carotenoids. SENECA Investigators

OBJECTIVE

Determination of the plasma vitamin and carotenoid concentrations of a number of elderly populations to describe their micronutrient status and examine geographical patterns and the cross-sectional and longitudinal relationships with sex, age, food and alcohol intake.

DESIGN

Longitudinal study.

SETTING

Twelve small towns in ten European countries and one in the USA.

SUBJECTS

Randomized sample of 1175 subjects of both sexes born in the period 1913-1918, stratified according to age and sex.

INTERVENTIONS

Blood plasma collection and determination of alpha-tocopherol, gamma-tocopherol, alpha-carotene, all-trans- and cis-beta-carotene, lycopene, lutein, zeaxanthin, beta-cryptoxanthin, vitamin B-12, folic acid and pyridoxal 5'-phosphate. From the original sample examined in 1988/1989, measurements were repeated in 938 subjects in 1993.

RESULTS

There were very large within and between country differences in the micronutrient levels with no definite geographical pattern emerging. The retinol levels decreased significantly between 1988/1989 and 1993 (-0.2 mumol/l, P = 0.0001), unlike the total carotene levels (0.01, NS) while the alpha-tocopherol (0.7 mumol/l, P = 0.002), folic acid (1.1 nmol/l, P < 0.01) and pyridoxal 5'-phosphate (12 nmol/l, P = 0.0001) levels increased significantly. Vitamin B-12 levels increased nonsignificantly in men (17.2 pmol/l, P = 0.77) and decreased significantly in women (-37 pmol/l, P = 0.012). The prevalence of biochemical vitamin A deficiency was zero in both 1988/1989 and 1993, that of vitamin E deficiency decreased from 1.1% to 0.6% and for vitamin B-6 from 23.3% to 5.7%. Vitamin B-12 biochemical deficiency increased from 2.7% to 7.3% and for folic acid from zero to 0.3%.

CONCLUSIONS

Changes in the median micronutrient plasma levels over a 4-y period varied, exceeding 30%-40% in some elderly populations. This was reflected in changes, mostly decreases, in the prevalences of vitamin deficiency.

Reference intervals for plasma apolipoprotein B determined with a standardized commercial immunoturbidimetric assay: results from the Framingham Offspring Study

We evaluated a commercially available, standardized immunoturbidimetric assay for apolipoprotein (apo) B, the protein constituent of low-density lipoprotein (LDL), to establish reference ranges for men and women, and to determine the concentrations associated with increased risk of coronary heart disease (CHD). The between-run CV for assay of a normal-concentration control for this assay was 6.60%. The mean (+/-SD) apo B concentration was 1.03 +/- 0.24 g/L in 1880 men, significantly higher than the mean for 1944 women (0.96 +/- 0.26 g/L) participating in cycle 4 of the Framingham Offspring Study (P<0.001). An apo B value of 1.20 g/L corresponded roughly to the 75th percentile in men, similar to an LDL cholesterol concentration of 1.60 g/L, and subjects with concentrations greater than this were significantly more likely to have CHD than subjects with apo B concentrations less than 1.00 g/L, the approximate 50th percentile (P<0.05 in men and P<0.001 in women).

Reference intervals for plasma apolipoprotein B determined with a standardized commercial immunoturbidimetric assay: results from the Framingham Offspring Study

We evaluated a commercially available, standardized immunoturbidimetric assay for apolipoprotein (apo) B, the protein constituent of low-density lipoprotein (LDL), to establish reference ranges for men and women, and to determine the concentrations associated with increased risk of coronary heart disease (CHD). The between-run CV for assay of a normal-concentration control for this assay was 6.60%. The mean (+/-SD) apo B concentration was 1.03 +/- 0.24 g/L in 1880 men, significantly higher than the mean for 1944 women (0.96 +/- 0.26 g/L) participating in cycle 4 of the Framingham Offspring Study (P&lt;0.001). An apo B value of 1.20 g/L corresponded roughly to the 75th percentile in men, similar to an LDL cholesterol concentration of 1.60 g/L, and subjects with concentrations greater than this were significantly more likely to have CHD than subjects with apo B concentrations less than 1.00 g/L, the approximate 50th percentile (P&lt;0.05 in men and P&lt;0.001 in women).

A rapid method for separation of plasma low and high density lipoproteins for tocopherol and carotenoid analyses

Ultracentrifugation (UC) is the method most often employed for separation and quantification of lipoproteins. Because this procedure requires expensive laboratory equipment, a large volume of fresh sample and an inordinate amount of time, it may not be ideal for routine clinical/experimental use. The aim of the current study was to evaluate a method which combines selective precipitation (HDL-P) and immunoseparation (LDL-I) for the rapid and reliable isolation of high density lipoproteins (HDL) and low density lipoproteins (LDL) specifically for vitamin E and carotenoid determination within these fractions. Cholesterol and triacylgylcerol concentrations within the HDL and LDL were also determined to enable expression of vitamin E and carotenoid concentrations per gram of lipid. Isolation of lipoproteins by UC was used as the reference method (HDL-UC/LDL-UC). There were no significant differences between methods for alpha- and gamma-tocopherol in LDL and HDL. Carotenoids measured in HDL and LDL were comparable between the methods. The exception was higher lutein/zeaxanthin concentration in HDL-P and LDL-I compared to HDL-UC and LDL-UC, respectively. Additionally, lycopene concentration was significantly lower in LDL-I compared to LDL-UC. In comparing vitamin E and carotenoid values in lipoproteins separated from fresh and frozen plasma by the direct method, there was no difference in alpha-tocopherol or the majority of carotenoids measured. In conclusion, a combination of selective precipitation and immunoseparation of fresh or frozen plasma for subsequent alpha- and gamma-tocopherol analyses provides an accurate and reliable alternative to lipoprotein separation by UC. Additionally, carotenoid concentrations in HDL separated by selective precipitation and analyses of alpha- and beta-carotenes and beta-cryptoxanthin in LDL separated by immunoseparation are also reliable, while lycopene and lutein/zeaxanthin concentrations in LDL-I are not readily comparable to LDL-UC.

Day-to-day variation in iron status indexes is similar for most measures in elderly women with and without rheumatoid arthritis

OBJECTIVE

To determine the day-to-day variation in biochemical measures of iron status in a group of elderly women with rheumatoid arthritis compared with a group of healthy elderly women.

DESIGN

Venous blood samples were collected from each subject on 3 nonconsecutive days during a 2-week study period; subjects had fasted overnight. Variability in hemoglobin level, hematocrit value, serum iron concentration, total iron-binding capacity, transferrin saturation, serum ferritin concentration, and plasma transferrin receptor level was determined.

SUBJECTS

Two groups of women, one with rheumatoid arthritis (n=10) and another that was apparently healthy (n=10).

STATISTICAL ANALYSES

Variance component analysis was used to estimate the biological variation (sigma square day) and analytic variation (sigma square rep) for each iron index. The coefficient of variation (CV) for each variance component was calculated: coefficient of biological variation = CV day, coefficient of analytic variation = CV rep, and coefficient of a single future determination = CV fd.

RESULTS

The CV rep for all iron indexes was smaller than the CV day in both groups. The CV day was considerably higher for serum iron concentration and for transferrin saturation than for the other indexes in both groups (16.6% and 16.6% in healthy subjects and 33.6% and 28.2%, respectively, in subjects with rheumatoid arthritis). The higher CV day for serum iron concentration and transferrin saturation translated into a higher CV fd for these indexes. Because of the higher variance for these two indexes, more sampling days were required for reliable estimates. CV day and CV fd for plasma transferrin receptor level were relatively low.

CONCLUSIONS

These findings corroborate our previous finding that variation of serum ferritin concentration in the elderly is lower than that demonstrated in younger populations. This aging effect persists in the presence of rheumatoid arthritis. Fasting appeared to improve reliability in the determinations for serum iron concentration and transferrin saturation. Variability estimates for the indexes other than serum iron concentration and transferrin saturation were not altered by the inflammation of rheumatoid arthritis. Plasma transferrin receptor level is a reliable index for assessing iron status in populations with rheumatoid arthritis.

Vitamin E in plasma and milk of lactating women with insulin-dependent diabetes mellitus

We measured levels of plasma and milk alpha-tocopherol in women with insulin-dependent diabetes mellitus (IDDM), women without IDDM, and healthy reference women. Milk collections were made at 7, 14, 42, and 84 days postpartum; blood was collected at 3, 14, and 42 days. Postprandial glucose at 80 min was used to describe metabolic control of women with IDDM postpartum. There was no difference between the groups for plasma alpha-tocopherol, which was within normal reported levels. Tocopherol (micrograms/g lipid) decreased by approximately 50% in all groups between 7 and 14 days. The trend for milk tocopherol was similar when expressed as micrograms/dl. Metabolic control did not have a significant effect on mean milk or plasma alpha-tocopherol. We have shown that this group of women with IDDM produced a milk with vitamin E content similar to control and reference women. We conclude that the infant of the breast-feeding woman with IDDM who is in good metabolic control during pregnancy and who receives good prenatal counseling most likely receives adequate vitamin E from the mother's milk.

Iron deficiency and anemia of chronic disease in elderly women: a discriminant-analysis approach for differentiation

To differentiate iron-deficiency anemia and anemia associated with chronic inflammatory diseases in elderly women, subsets of laboratory, dietary, and functional assessment variables were obtained by using discriminant analysis. Fifty-one subjects (70-79 y of age) were classified into one of four groups on the basis of the presence of iron deficiency and chronic inflammatory disease. Iron deficiency was defined on the basis of a significant response in hemoglobin concentration after iron supplementation. The discriminating subset of laboratory tests consisted of measures for serum ferritin, plasma transferrin receptors, and erythrocyte sedimentation rate. The discriminant function classified subjects into iron-deficient, anemia of chronic disease, or a category in which the two coexist, with an error rate of 18.6%. The addition of other variables (dietary iron and functional assessment information) did not appreciably improve the classification. The results of these three key laboratory tests may help to identify functional iron deficiency in the presence of chronic inflammation.

Total lipid and fatty acid composition of milk from women with and without insulin-dependent diabetes mellitus

Milk lipid and fatty acids were measured from women with insulin-dependent diabetes mellitus (IDDM), a comparison group of women without diabetes, and reference women. Milk samples were collected 80 min after breakfast at 2, 3, 7, 14, 42, and 84 d postpartum (pp). Total lipid and medium-chain fatty acids (MCFAs) in the group with IDDM were similar to or greater than those of control and reference groups at all times and were within normal, reported ranges. Milk long-chain polyunsaturated fatty acids (LC-PUFAs) were lower in women with IDDM from 14 to 84 d pp. Lower milk LC-PUFAs may be a result of altered fatty acid metabolism in women with IDDM.

Rat embryo development on human sera is related to numbers of previous spontaneous abortions and nutritional factors

OBJECTIVES

The objectives were to determine (1) if sera from women with histories of spontaneous abortions were teratogenic to cultured embryos more often than were sera of nonaborters, (2) if the teratogenicity could be corrected by adding nutrients to the sera, and (3) if these findings were relevant to reproductive outcomes.

STUDY DESIGN

Rat embryos were cultured for 48 hours on sera from 102 subjects who had experienced spontaneous abortions. Samples from 48 were retested with nutrients added and 10 took dietary supplements, were again tested with embryo cultures, and reported on their pregnancy outcomes.

RESULTS

The frequencies of teratogenic sera increased with numbers of spontaneous abortions (0 to > or = 5) in a manner that did not deviate from linearity (27% to 89%) (chi 2 p > 0.957). Nutrient supplements were added to 48 samples, and 40 were corrected and 10 subjects were given dietary supplement. Sera from six showed improved embryo cultures, and these women completed their pregnancies.

CONCLUSIONS

Rat embryo cultures may provide unique insights into the causes and treatment of spontaneous abortions.

Delayed lactogenesis in women with insulin-dependent diabetes mellitus

Breast milk lactose, total nitrogen, conductivity, osmolality, and intake by infants of 33 women with insulin-dependent diabetes mellitus (IDDM), 33 control women without diabetes, and 11 reference women were determined in a 3-mo study of lactation. Milk of women with IDDM had significantly lower lactose and higher total nitrogen (2-3 d postpartum), and their infants had significantly less milk intake (7-14 d postpartum) than did control or reference women. Total nitrogen was negatively correlated with milk lactose for women with IDDM at all times and for control women through day 14 postpartum. The data indicate delayed lactogenesis for women with IDDM, which was more likely to occur with poor metabolic control. Differences in milk composition of women with IDDM do not preclude them from breast-feeding their infants.

Day-to-day variation in iron-status indexes in elderly women

Day-to-day variability in biochemical indicators of iron status in well-hydrated and healthy women 70-79 y old (n = 10) was determined. Venous blood was collected on 4 nonconsecutive days during a 2-wk period. Analytical (sigma 2 rep) and biological (sigma 2 fd) variance components were computed based on a previously established scheme in younger adults. These two variance components were summed to obtain the total day-to-day variability (sigma 2 fd). Our results indicate that biological variation contributed most to the intraindividual variation. We calculated that sampling once for most iron indexes and twice for plasma transferrin receptors in elderly individuals is adequate to accurately determine these indexes whereas serum iron and transferrin saturation, indexes with high CVfd, require seven and eight measurements, respectively. These data, compared with previously published data in younger adults, demonstrate that aging is associated with a decreased variation in some indexes of iron status such as serum ferritin.

Effect of fish oil on the fatty acid composition of human milk and maternal and infant erythrocytes

To examine the effect of fish oil supplementation on the fatty acid (FA) composition of human milk and maternal and infant erythrocytes, five lactating women were supplemented with 6 g of fish oil daily for 21 d. Usual maternal diets contained 1,147 mg of total n-3 FA, with 120 mg from very long-chain (> C18) n-3 FA. Supplementation increased dietary levels to 3,092 mg of total n-3 FA and 2,006 mg of very long-chain n-3 FA. Milk samples were collected daily, prior to fish oil ingestion, and at 4-h intervals on days 1, 7, 14 and 21. Milk n-3 FA content increased within 8 h and reached steady state levels within one week. The n-6 fatty acid content decreased. Erythrocyte eicosapentaenoic acid content increased from 0.24% to 1.4% (P < 0.01) in mothers and from 0.11% to 0.70% (P < 0.05) in infants. Docosapentaenoic acid increased from 1.4% to 2.2% (P < 0.05) in mothers and from 0.30% to 0.78% (P < 0.01) in infants. There was no significant change in docosahexaenoic acid or n-6 fatty acid content. Maternal platelet aggregation responses were variable. No differences in milk or plasma tocopherol levels were noted.

Lipids in human milk and infant formulas

About 50 metabolically important fatty acids can be identified in human milk. The extent of absorption of milk fatty acids varies considerably from infant to infant, particularly in pre-term infants, and requires more study. Human milk provides sufficient vitamins A and E for the term infant, but supplementation with vitamins D and K may be necessary. More research is needed on the amounts of the fat-soluble vitamins in human milk, the efficiency of transfer from mother to infant, the reasons for variation in different women, and the consequences to breast-fed infants of inadequate intake of vitamins D and K. Breast milk contains the PUFA needed by term infants who are able to synthesize the long-chain PUFA soon after birth. Pre-term infants fed formulae need supplementation with n3 and n6 long-chain PUFA, since formulas currently do not contain these acids. More work is needed to determine the requirements for n3 and n6 fatty acids, expressed as weights per kilogram. A larger data base using improved analytical procedures to study the nature and content of lipids in human milk is needed. The impact of maternal genetics and diet on fatty acids in milk should be studied, as well as the effect of maternal diet on eicosanoids secreted by the mammary gland. Information on the structure and function of the milk fat globule and its membrane is needed. Little is known about the effect of milk banking on milk lipids. The reader of this review will no doubt find other gaps in our knowledge of the lipid composition and nutritional value of milk that require additional investigation.

Effect of dietary intake of n-6 and n-3 fatty acids on the fatty acid composition of human milk in North America

To determine the effect of maternal dietary n-6 and n-3 polyunsaturated fatty acids (PUFA) on the amounts of these fatty acids in human milk, two criteria must be met. These are assessment of the maternal diet and accurate analysis of the milk fatty acids. This type of analysis requires gas-liquid chromatography with capillary columns to resolve important n-6 and n-3 C20 and C22 fatty acid. This type of analytic equipment has only recently become available; thus the amount of complete data on human milk fatty acids is limited. To assess actual fatty acid intakes by the infant, the fat content and volume of milk received by the infant must be known. Alterations in maternal dietary intake of PUFA cause similar changes in milk PUFA. Several investigators have shown that maternal supplementation with fish oils increases the amounts of 20:5n-3 and 22:6n-3 in milk and maternal and infant erythrocyte lipids. A new mathematic index for assessment of essential fatty acid status, the mean melting point of plasma phospholipid fatty acids, has been proposed. We found in some mother-infant pairs that maternal supplementation with fish oil lowered the mean melting points of erythrocyte lipids to levels seen in nonpregnant women.

The composition of milk fat

Bovine milk contains about 3.5 to 5% total lipid, existing as emulsified globules 2 to 4 microns in diameter and coated with a membrane derived from the secreting cell. In homogenized milk, the coat is mostly casein. About 98% or more of the lipid is triacylglycerol, which is found in the globule. Phospholipids are about .5 to 1% of total lipids, and sterols are .2 to .5%. These are mostly located in the globule membrane. Cholesterol is the major sterol at 10 to 20 mg/dl. Data are presented on the membrane and the emulsion. Bovine milk contains substantial quantities of C4:0 to C10:0, about 2% each of C18:2 and trans-C18:1, and almost no other long-chain polyunsaturated fatty acids. The fatty acid composition is not altered by ordinary changes in diet. The triacylglycerol structure is unique, with much of the C4:0 to C10:0 at sn-3. The effects of milk cholesterol and fatty acids on human blood cholesterol levels and nonnutritive roles of some microlipids are discussed.

Changes in human milk at 0600, 1000, 1400, 1800, and 2200 h

Milk from six mothers was collected every 4 h from 0600 to 2200 h. Total lipid and cholesterol, lactose, glucose, protein N, indicator acids 12:0, 14:0, and 18:2, and alpha- and gamma-tocopherols were analyzed. Total calories were calculated. Although considerable variation was seen in the lipid content, this was not significant and was apparently due to individuality. Differences in the other lipid components were not significant and were generally related to the total lipid content. Except for protein N (p less than 0.05), none of the other components varied significantly. Based upon these data and the results of others, the time of sampling of human milk should be matched to the population being studied to obtain consistent results, at least with lipids.

Lipids of bovine and human milks: a comparison

Human and bovine milks contain about 3 to 5% total lipid, existing as emulsified globules 2 to 4 microns in diameter and coated with a membrane derived from the secreting cell. About 98% or more of the lipid is triacylglycerol, which is found in the globule. Phospholipids are about .5 to 1% of total lipids and sterols are .2 to .5%; these are mostly located in the globule membrane. Cholesterol is the major sterol. The major differences are in fatty acid composition, triacylglycerol structure, and the response of fatty acids in human milk to changes in diet. Bovine milk contains substantial quantities of 4:0 to 10:0, about 2% 18:2, and almost no other long-chain polyunsaturated fatty acids. The fatty acid composition is not altered by ordinary changes in diet. Human milk contains very little 4:0 to 10:0, 10 to 14% 18:2, and small quantities of other polyunsaturates. The triacylglycerol structure differs, with much of the sn-2 position occupied by 16:0 in human milk and 4:0 to 10:0 at sn-3 in bovine milk. The effects of milk cholesterol and fatty acids on human blood cholesterol levels are discussed.

The simultaneous separation and quantitation of human milk lipids

A protocol using a dry column method was modified for the extraction of total lipids and the simultaneous separation and quantitation of neutral and polar lipids in human milk. The triacylglycerol, cholesterol, phospholipid and vitamin E contents of the lipid extracts were determined and compared with lipids extracted using a modified Folch procedure. Good precision for the extraction of neutral, polar and total lipids, as well as the different lipid classes, was demonstrated. No significant differences were found between the two methods with respect to the amount of cholesterol, phospholipid, total lipid or vitamin E extracted, thus validating the method as an extraction technique. We discuss the relationship between vitamin E and the three major milk lipids as an indicator of the vitamin's place of origin in the mammary gland. Our findings do not support the idea that vitamin E in mature milk has its original location in the apical membrane.

Alpha and gamma tocopherols in pooled mature human milk after storage

The alpha- and gamma-tocopherols in pooled stored human milk were determined. Storage times and temperatures were t = 0 (up to 2 h after start of pool collection); t = 8 h (25 degrees, 4 degrees C); t = 24 h (25 degrees, 4 degrees, -11 degrees C); and t = 72 h, 1, 4, 8, and 16 weeks (-11 degrees, -20 degrees, -70 degrees C). Lipids were extracted with a modified Folch procedure and tocopherols were analyzed with high-performance liquid chromatography. There were no significant differences in alpha- or gamma-tocopherol at any time or temperature. Therefore, mothers, milk bank operators, and researchers can be assured of the stability of tocopherol in human milk stored under the conditions of this study.

Tocopherols in human milk: analytical method using high-performance liquid chromatography

A procedure for the determination of tocopherols in human milk using normal phase high-performance liquid chromatography (HPLC) is described. The method involves extraction of the total lipid from milk and direct injection of the dissolved lipid into the HPLC without further fractionation. Operating conditions are as follows: instrument, Varian Model 5000 Liquid Chromatograph; column, Alltech-NH2 (25 cm X 4.6 mm); solvents, n-hexane:2-propanol (98:2); flow rate, 2.0 ml/min; detector, 290 nm; and absorbance range, 0.01. Chromatographic separation of the tocopherol isomers, alpha, beta, gamma, and delta, was achieved. The tocopherol isomers of milk were separated, allowing quantitation of alpha- and gamma-tocopherol, the predominant milk isomers. Good recovery, reproducibility, and precision for the method were demonstrated.

Effect of level of dietary protein and total or partial starvation on catalase and superoxide dismutase activity in cardiac and skeletal muscles in young rats

In cells the level of potentially toxic superoxide radical (O2-) is controlled by superoxide dismutase (SOD); the level of hydrogen peroxide (H2O2), also potentially toxic, is controlled by catalase and glutathione peroxidase. To study the effects of altered food intake or dietary protein content on SOD and catalase in cardiac and skeletal muscles, young rats were fed ad libitum diets containing 3, 6 or 25% casein or were subjected to total or partial food restriction (resulting in similar body weight losses). Rats fed a diet containing 3 or 6% casein had much lower growth rates than those fed 25% casein, but the muscle catalase activities were similar in all three groups. Catalase activities in muscles of rats whose food intake was restricted were twice those in rats fed ad libitum. Rats fed ad libitum had higher muscle SOD activities at 41 days of age than did 25-day-old rats, irrespective of the amount of dietary protein or the rate of growth. Twenty-five-day-old rats whose food intake was totally restricted for 2 days had skeletal muscle SOD activities similar to the higher activities seen at 41 days of age in ad libitum-fed rats, but SOD activity in the heart was unchanged after food restriction. The responses of catalase and SOD in muscles differ from the responses reported for these enzymes in liver and erythrocytes when food intake or dietary protein is altered.

Evidence for increased peroxidative activity in muscles from streptozotocin-diabetic rats

The ability of cardiac and skeletal muscles from diabetic rats to metabolize superoxide and hydrogen peroxide was determined by the activities of superoxide dismutase (SOD) and catalase, respectively. Male and female Sprague-Dawley rats, 43 days old, were made diabetic with a single intravenous injection of streptozotocin (70 mg/kg body weight). On the 80th day after injection the blood glucose concentration of these rats was increased fourfold, and the plasma insulin concentration was decreased four- to fivefold compared to controls. Body weights of male diabetic rats were 61% and those of female diabetic rats were 66% of their ad libitum-fed controls. The seven different skeletal muscles examined weighed less in the diabetic rats than in controls of the same age and body weight. The hearts of the diabetic rats weighed more than those of controls of the same age and body weight. Comparison to the body weight controls allowed the distinction of specific effects due to lack of insulin from effects due to retardation in muscle growth. Increased catalase activity in all muscles examined from diabetic rats (plantaris, gastrocnemius, and heart) suggested a response in catalase activity similar to that of starved rats. SOD activity was not altered in the diabetic rat skeletal muscles and erythrocytes, but was somewhat decreased in the heart.

Lipids in human milk: a review. 2: Composition and fat-soluble vitamins

Recent work on lipid classes and the fatty acid composition of milk is reviewed. At least 98% of the lipids are triacylglycerols with about 1% phospholipids and 0.3-0.4% cholesterol. Desmosterol has been identified. The major phospholipids (% of total) are: sphingomyelin (32), phosphatidylcholine (25), and phosphatidylethanolamine (28). The 12:0 content of colostrum is lower than that of mature milk. The 18:2 content of mature milk can be altered by diet; otherwise, the fatty acid composition is remarkably constant. Long-chain polyunsaturates appear to be needed for development of the infant's brain and nervous system. Data on the contents of these acids are given. The fat-soluble vitamins have been analyzed by high-performance liquid chromatography. The amounts of vitamins D and K in milk, unlike those of A and E, are lower than the quantities required to meet the U.S. Recommended Daily Allowances. Vitamin D sulfate does not appear to be a significant antirachitic component of human milk. Nutritional and analytical aspects are emphasized throughout and areas for future investigations indicated.

Copper-zinc and manganese superoxide dismutase activities in cardiac and skeletal muscles during aging in male rats

The activities of total superoxide dismutase (SOD) and the manganese (Mn SOD) and copper-zinc (Cu-Zn SOD) forms were determined in the supernatant fraction of heart, liver and six skeletal muscles from rats during aging. Total SOD activity increased in most muscles between 3 and 23 months of age. There was no change in activity in liver between 3 and 19 months of age. The increase in total activity in heart was due to increased Mn SOD activity, whereas increases in skeletal muscles were due to Cu-Zn SOD or to both Cu-Zn and Mn SOD. The nutritional implications during aging are discussed.

Influence of dietary omega-3 fatty acids on granulocyte function

Manipulation of dietary fatty acid content has been shown to influence platelet aggregation responses. Because granulocytes and platelets interact in a variety of biologic systems, we wondered whether a similar effect might be observed on granulocytes. Granulocyte function was therefore studied in three donors prior to and after three weeks upon a diet supplemented with large amounts of eicosapentaenoic acid. The previously reported attenuation of platelet aggregation was observed, but no effect was seen on granulocyte aggregation, chemotaxis, or superoxide production. Although several other explanations are possible, we suggest that the most likely explanation for this dichotomy is that granulocyte aggregation and chemotaxis are not centrally dependent upon production of thromboxane A.