A highly saturated fat-rich diet is more obesogenic than diets with lower saturated fat content

The present study tested the hypothesis that a saturated fatty acid (SFA)–rich diet is more obesogenic than diets with lower SFA content. In 8 female Sprague-Dawley rats fed a low-SFA canola or a moderate-SFA lard-rich diets at 67% of energy for 26 days, body weight gain, final body weight, obesity index, and food and energy intake were comparable. Twenty-nine rats were fed canola or high-SFA butter-rich diets (67% of energy) or chow for 50 days; then high-fat feeding was followed by ad libitum low-fat feeding (27% of energy) for 28 days and by a food-restricted low-fat diet for 32 days. High-fat feeding resulted in a greater body weight gain (P < .04), final body weight (P < .04), and energy intake (P < .008) in butter-fed rats than in canola- and chow-fed controls, after 26 or 50 days. Ad libitum canola and butter low-fat diets or chow feeding resulted in similar weight change, whereas food-restricted low-fat diets led to comparable weight loss and final weight. Canola-fed animals adjusted their intake based on diet energy density, whereas lard and butter-fed animals failed to do so. Abdominal fat (P = .012) and plasma leptin (P = .005) were higher in chow-fed controls than in canola-fed rats, but comparable with those of butter-fed rats. Prone and resistant phenotypes were detected with high-fat feeding. In conclusion, only feeding the high-SFA butter-rich diet led to obesity development and failure to adjust intake based on the energy density and preserving body fat even after weight loss. The high availability of SFA-rich foods in today's obesogenic environment could contribute to develop and maintain obesity.     

An isoenergetic very low carbohydrate diet improves serum HDL cholesterol and triacylglycerol concentrations,the total cholesterol to HDL cholesterol ratio and postprandial pipemic responses compared with a low fat diet in normal weight,normolipidemic women

Very low carbohydrate diets are popular, yet little is known about their effects on blood lipids and other cardiovascular disease risk factors. We reported previously that a very low carbohydrate diet favorably affected fasting and postprandial triacylglycerols, LDL subclasses and HDL cholesterol (HDL-C) in men but the effects in women are unclear. We compared the effects of a very low carbohydrate and a low fat diet on fasting lipids, postprandial lipemia and markers of inflammation in women. We conducted a balanced, randomized, two-period, crossover study in 10 healthy normolipidemic women who consumed both a low fat (<30% fat) and a very low carbohydrate (<10% carbohydrate) diet for 4 wk each. Two blood draws were performed on separate days at 0, 2 and 4 wk and an oral fat tolerance test was performed at baseline and after each diet period. Compared with the low fat diet, the very low carbohydrate diet increased (P 相似文献   

Long-term consumption of a raw food diet is associated with favorable serum LDL cholesterol and triglycerides but also with elevated plasma homocysteine and low serum HDL cholesterol in humans

High consumption of vegetables and fruits is associated with reduced risk for cardiovascular disease. However, little information is available about diets based predominantly on consumption of fruits and their health consequences. We investigated the effects of an extremely high dietary intake of raw vegetables and fruits (70-100% raw food) on serum lipids and plasma vitamin B-12, folate, and total homocysteine (tHcy). In a cross-sectional study, the lipid, folate, vitamin B-12, and tHcy status of 201 adherents to a raw food diet (94 men and 107 women) were examined. The participants consumed approximately 1500-1800 g raw food of plant origin/d mainly as vegetables or fruits. Of the participants, 14% had high serum LDL cholesterol concentrations, 46% had low serum HDL cholesterol, and none had high triglycerides. Of raw food consumers, 38% were vitamin B-12 deficient, whereas 12% had an increased mean corpuscular volume (MCV). Plasma tHcy concentrations were correlated with plasma vitamin B-12 concentrations (r = -0.450, P < 0.001), but not with plasma folate. Plasma tHcy and MCV concentrations were higher in those in the lowest quintile of consumption of food of animal origin (P(trend) < 0.001). This study indicates that consumption of a strict raw food diet lowers plasma total cholesterol and triglyceride concentrations, but also lowers serum HDL cholesterol and increases tHcy concentrations due to vitamin B-12 deficiency.     

Maintenance of the LDL cholesterol:HDL cholesterol ratio in an elderly population given a dietary cholesterol challenge

We previously evaluated the responses to dietary cholesterol in children and young adults. In this study, the effects of dietary cholesterol on plasma lipids and LDL atherogenicity were evaluated in 42 elderly subjects (29 postmenopausal women and 13 men > 60 y old). Our exclusion criteria were diabetes, heart disease, and the use of reductase inhibitors. The study followed a randomized crossover design in which subjects were assigned to consume the equivalent of 3 large eggs (EGG) daily or the same amount of a cholesterol-free, fat-free egg substitute (SUB) for a 1-mo period. After a 3-wk washout period, subjects were assigned to the alternate treatment. The concentration of plasma cholesterol after the EGG period varied among subjects. When all subjects were evaluated, there were significant increases in LDL cholesterol (LDL-C) (P < 0.05) and HDL-C (P < 0.001) for both men and women during the EGG period, resulting in no alterations in the LDL-C:HDL-C or the total cholesterol:HDL-C ratios. In addition, the LDL peak diameter was increased during the EGG period for all subjects. In contrast, the measured parameters of LDL oxidation, conjugated diene formation, and LDL lag time did not differ between the EGG and the SUB periods. We conclude from this study that dietary cholesterol provided by eggs does not increase the risk for heart disease in a healthy elderly population.     

Stearic acid-rich interesterified fat and trans-rich fat raise the LDL/HDL ratio and plasma glucose relative to palm olein in humans

Sulfur, after calcium and phosphorus, is the most abundant mineral element found in our body. It is available to us in our diets, derived almost exclusively from proteins, and yet only 2 of the 20 amino acids normally present in proteins contains sulfur. One of these amino acids, methionine, cannot be synthesized by our bodies and therefore has to be supplied by the diet. Cysteine, another sulfur containing amino acid, and a large number of key metabolic intermediates essential for life, are synthesized by us, but the process requires a steady supply of sulfur. Proteins contain between 3 and 6% of sulfur amino acids. A very small percentage of sulfur comes in the form of inorganic sulfates and other forms of organic sulfur present in foods such as garlic, onion, broccoli, etc. The minimal requirements (RDA) for all the essential amino acids have always been estimated in terms of their ability to maintain a nitrogen balance. This method asses amino acid requirements for protein synthesis, only one of the pathways that methionine follows after ingestion. To adequately evaluate the RDA for methionine, one should perform, together with a nitrogen balance a sulfur balance, something never done, neither in humans nor animals. With this in mind we decided to evaluate the dietary intake of sulfur (as sulfur amino acids) in a random population and perform sulfur balance studies in a limited number of human volunteers. Initially this was done to try and gain some information on the possible mode of action of a variety of sulfur containing compounds (chondroitin sulfate, glucosamine sulfate, and others, ) used as dietary supplements to treat diseases of the joints. Out of this study came information that suggested that a significant proportion of the population that included disproportionally the aged, may not be receiving sufficient sulfur and that these dietary supplements, were very likely exhibiting their pharmacological actions by supplying inorganic sulfur.     

The effect of dietary fat on LDL size is influenced by apolipoprotein E genotype in healthy subjects

LDL particle size is dependent on both genetic factors and environmental factors such as dietary fat composition. The apolipoprotein E (apoE) genotype is a major genetic determinant of LDL size. Thus, the aim of this work was to study whether the apoE genotype interacts with the quantity and quality of dietary fat, modifying LDL size in young healthy subjects. Healthy subjects (n = 84; 66 apoE 3/3, 8 apoE 4/3, 10 apoE 3/2) were subjected to 3 dietary periods, each lasting 4 wk. The first was an SFA-enriched diet (38% fat, 20% SFA), which was followed by a carbohydrate (CHO)-rich diet (30% fat, < 10% SFA, 55% carbohydrate) or a monounsaturated fatty acid (MUFA) olive oil-rich diet (38% fat, 22% MUFA) following a randomized crossover design. At the end of each diet period, LDL particle size and plasma levels of total cholesterol, LDL cholesterol (LDL-C), HDL-C, apoB, apoA-I, and triacylglycerols were determined. LDL particle size was significantly higher (P < 0.04) in subjects with the apoE 4/3 genotype compared with those with apoE 3/3 and apoE 3/2 in the basal state. LDL size was smaller (P < 0.02) after the CHO diet than after the MUFA or SFA diets. After the CHO diet, a significant increase in LDL particle size (P < 0.035) was noted with respect to the MUFA diet in apoE 4/3 subjects, whereas a significant decrease was observed in the apoE 3/3 individuals (P < 0.043). In conclusion, a Mediterranean diet, high in MUFA-fat increases LDL particle size compared with a CHO diet, and this effect is dependent of apoE genotypes.     

Lowering dietary saturated fat and total fat reduces the oxidative susceptibility of LDL in healthy men and women

The present study examined the effects of reducing dietary total fat and saturated fat (SFA) on LDL oxidative susceptibility in 27 healthy men and women (age 24-65 y). Each subject consumed each of three diets for 8 wk: an average American diet (AAD, 34% energy from fat, 15% from SFA), a Step-1 diet (29% fat, 9% SFA) and a very low SFA diet (Low-Sat, 25% fat, 6% SFA). In vitro LDL oxidation was assessed by copper-mediated oxidation, as measured by the kinetics of conjugated diene formation and lipid peroxide formation. Compared with the AAD, plasma LDL-cholesterol (LDL-C) and HDL cholesterol levels were 8% lower (P: = 0.16 and P: = 0.11, respectively), in subjects when they consumed the Step-1 diet and 11% (P: < 0.03) and 14% (P: < 0.057) lower, respectively, when they consumed the Low-Sat diet. Conjugated diene production and oxidation rate were 7% (P: < 0. 05) and 9% (P: < 0.05) lower, respectively. The reduction of lipid peroxide formation was 9% (P: < 0.05) in subjects when they consumed the Low-Sat diet vs. the AAD. In addition, lipid peroxide and conjugated diene formation were positively correlated with plasma total and LDL-C and apolipoprotein B (apo B) levels (r = 0.5-0.6, P: < 0.001), suggesting that quantity of LDL is an important determinant of oxidative modification. Furthermore, at the same level of apo B or LDL-C, LDL from subjects when they consumed either Step-1 or Low-Sat diets was less susceptible (P: < 0.05) to oxidation than those when they consumed the AAD, suggesting that qualitative changes also affect LDL oxidative susceptibility. Therefore, the benefits of lowering dietary SFA may extend beyond decreasing LDL-C levels and include favorable qualitative changes in LDL that further decrease risk of coronary heart disease.     

Milk sphingomyelin is more effective than egg sphingomyelin in inhibiting intestinal absorption of cholesterol and fat in rats

We reported previously that egg sphingomyelin (SM) inhibits the intestinal absorption of cholesterol and fat in rats. This study was conducted to compare the relative efficiencies of milk and egg SM in inhibiting intestinal absorption of cholesterol and other lipids. Adult male rats with lymph cannulae were infused at 3.0 mL/h for 8 h via a duodenal catheter with a lipid emulsion (451.7 micromol triolein, 20.7 micromol cholesterol, 33.3 kBq (14)C-cholesterol, 3.1 micromol alpha-tocopherol, and 396.0 micromol sodium taurocholate in 24 mL PBS, pH, 6.5), without SM (controls), or with 80.0 micromol egg SM or milk SM. The lymphatic absorptions of (14)C-cholesterol were significantly lower in rats infused with milk SM (19.5 +/- 1.4% dose) and egg SM (24.4 +/- 1.9% dose) than in those infused with no SM (37.6 +/- 1.8% dose). In addition, the lymphatic outputs of fatty acids and phospholipid were significantly lowered by milk and egg SM. Similarly, the absorption of alpha-tocopherol also was decreased by milk SM (13.6 +/- 1.7% dose) and egg SM (18.3 +/- 2.4% dose) compared with controls (27.0 +/- 1.8% dose). Total lymphatic SM output was not affected by egg SM, but markedly decreased by milk SM, relative to controls. The results indicate that both milk and egg SM markedly inhibit the absorption of cholesterol, fat, and other lipids. However, milk SM is a more potent inhibitor than egg SM. The strong inhibitory effect of milk SM may be associated with the higher degree of saturation and longer chain length of its fatty acyl groups, which may slow the rate of luminal lipolysis, micellar solubilization, and transfer of micellar lipids to the enterocyte.     

Maternal diet rich in saturated fat during breastfeeding is associated with atopic sensitization of the infant

OBJECTIVE: To investigate the impact of maternal diet during breastfeeding on atopic sensitization of infants at risk. DESIGN: Prospective cohort study. SETTING: Turku University Central Hospital, Finland. SUBJECTS AND METHODS: Altogether 114 infants with a family history of atopic disease were followed during their first year of life. The mothers completed a 4 day food record during breastfeeding just before the infants were 3 months old. Atopic sensitization of the infants was determined by a positive skin prick test result at 12 months. RESULTS: Positive skin prick test reactivity to at least one antigen was detected in 27/114 (24%) infants at 12 months. The energy intake of the mothers was low, mean 8.0 MJ/day (95% CI 7.7-8. 3), and the proportion of energy derived from fat was high, mean 36. 6 E% (95% CI 35.6-37.6). Atopic mothers had a higher intake of total fat and saturated fat and a lower intake of carbohydrate as a percentage of total energy intake than non-atopic mothers; P=0.017, P=0.050, P=0.004 respectively. Maternal intake of saturated fat during breastfeeding was associated with atopic sensitization of the infant, OR=1.16 (95% CI 1.001-1.36); P=0.048 irrespective of the maternal atopic status. CONCLUSIONS: Our results show that an unbalanced maternal diet during breastfeeding may be a risk factor underlying the later development of atopic sensitization of the infant regardless of maternal atopic disease. The observation thus extends findings implying that early nutrition programmes the subsequent health of the child to the risk of developing atopic disease. SPONSORSHIP: Academy of Finland and National Technology Agency.     

The effect of a high cholesterol and saturated fat diet on serum high-density lipoprotein-cholesterol, apoprotein A-I, and apoprotein E levels in normolipidemic humans

The effects of a high cholesterol, high saturated fat diet on serum high density lipoprotein cholesterol, apo A-I, and apo E levels were studied in six normolipidemic subjects. The study was done on an outpatient basis and mixed natural foods normally consumed by humans were used. When compared with a low cholesterol (98 mg/day) high polyunsaturated fat (P/S ratio 1.6) diet, the high cholesterol (1021 mg/day), high saturated fat (P/S ratio 0.4) diet increased serum cholesterol (23%) by raising the cholesterol concentration in very low-density lipoproteins (59%), low-density lipoproteins (15%), and high-density lipoproteins (30%). The low-density lipoprotein-cholesterol/high-density lipoprotein-cholesterol ratio fell significantly from 1.78 to 1.58. The increased high-density lipoprotein-cholesterol was associated with an elevation of serum apo A-I but not apo E. Serum triglycerides did not change significantly.     

The small dense LDL particle/large buoyant LDL particle ratio is associated with glucose metabolic status in pregnancy

Background

The lipoprotein subfraction particle profile can be used to improve clinical assessments of cardiovascular disease risk and contribute to early detection of atherogenic dyslipidemia. Lipid alterations in gestational diabetes have been extensively studied, but the results have been inconsistent. Here, we investigated serum lipoprotein subfraction particle levels and their association with glucose metabolic status in pregnancy.

Methods

Twenty-eight pregnant women with gestational diabetes and 56 pregnant women with normal glucose tolerance matched for body mass index were enrolled in this study. We assessed fasting serum lipid concentrations and lipoprotein subfraction particle levels in participants between 24 and 28 weeks of gestation.

Results

The level of low-density lipoprotein (LDL) cholesterol was significantly lower in women with gestational diabetes than in those with normal glucose tolerance, but the triglyceride and high-density lipoprotein (HDL) cholesterol levels of the two groups were similar. Lipoprotein particle analysis showed that very-low-density lipoprotein (VLDL) particle number and the small dense LDL particle/large buoyant LDL particle (sdLDL-P/lbLDL-P) ratio were significantly higher in women with gestational diabetes than in those with normal glucose tolerance (P?=?0.013 and P?=?0.015, respectively). In multivariate analysis, fasting glucose was independently and positively associated with sdLDL-P/lbLDL-P ratio even after adjustment for maternal age, gestational weight gain, BMI and LDL cholesterol (standardized Beta?=?0.214, P?=?0.029).

Conclusions

The sdLDL-P/lbLDL-P ratio is higher in GDM compared with non-diabetic pregnant women, and positively and independently associated with fasting glucose in pregnant women.

     

Asian ethnicity is associated with a higher trunk/peripheral fat ratio in women and adolescent girls

Background

Ethnic differences in body fat mass and distribution may develop in childhood and contribute to increased obesity-related disease risk among Asians. We used dual-energy X-ray absorptiometry (DXA) to evaluate adiposity measures among adult women and their adolescent daughters, who were of predominantly Japanese and white ethnicity.

Methods

We obtained DXA whole body scans for 101 mothers aged 30 years or older and 112 daughters aged 10 to 16 years. The participants were classified as Asian, part-Asian, mixed/other, or white. As a measure of central adiposity, we calculated the trunk/peripheral fat ratio (TPFR). General linear models were used to evaluate differences in adiposity measures by ethnic category.

Results

In mothers, TPFR was significantly higher (P_trend < 0.01) in Asians and part-Asians (1.38 ± 0.42 and 1.32 ± 0.51) than in mixed/others and whites (1.18 ± 0.27 and 1.09 ± 0.21). The trend was similar among daughters (P_trend < 0.001), with respective values of 1.09 ± 0.18, 0.97 ± 0.17, 0.99 ± 0.16, and 0.87 ± 0.11. Among mothers, gynoid fat mass and peripheral fat mass were significantly lower in Asians than in whites, whereas none of the regional DXA adiposity measures differed by ethnicity in daughters.

Conclusions

These results confirm previous reports of greater central adiposity in women of Asian ancestry and indicate that ethnic differences in adiposity are already present in adolescence.Key words: DXA, trunk/peripheral fat ratio, central adiposity, ethnicity     

Asian ethnicity is associated with a higher trunk/periphery fat ratio in women and adolescent girls

OBJECTIVE: Ethnic differences in body fat mass and distribution may develop in childhood and contribute to the elevated obesity-related disease risk among Asians. We evaluated adiposity measures of adult women and their adolescent daughters of predominantly Japanese and Caucasian ethnicity using Dual Energy X-ray Absorptiometry (DXA). METHODS: We obtained DXA whole body scans for 101 mothers aged ≥30 years and 112 daughters aged 10-16 years who were classified as Asian, Part-Asian, Mixed-Other, and Caucasian. As a measure of central adiposity, we calculated the trunk/periphery fat ratio (TPFR). General linear models were applied to evaluate differences in adiposity measures by ethnic category. RESULTS: In mothers, TPFR was significantly higher (p(trend)=0.01) in Asians and Part-Asians (1.38±0.42 for and 1.32±0.51) than in Mixed-Others and Caucasians (1.18±0.27 and 1.09±0.21). Daughters showed a similar trend (p(trend) =0.001) with respective values of 1.09±0.18, 0.97±0.17, 0.99±0.16, and 0.87±0.11. Among mothers, gynoid fat mass and periphery fat mass were significantly lower in Asians than Caucasians, whereas none of the regional DXA adiposity measures in girls differed by ethnicity. CONCLUSIONS: These results confirm previous reports of greater central adiposity in women of Asian ancestry and indicate that ethnic differences in adiposity are already present in adolescence.     

亮氨酸对高脂高胆固醇喂养小鼠瘦素抵抗影响

目的 探讨亮氨酸对高脂高胆固醇喂养小鼠体脂和瘦素抵抗的影响。方法 60只雄性C57BL/6J小鼠随机分为对照组、高脂高胆固醇组、低、高剂量亮氨酸组（1.5%、3.0%亮氨酸）,干预24周;测定小鼠体重、脂肪重量、血清胆固醇和瘦素水平,Western blot法检测小鼠睾周脂肪组织中瘦素受体（Ob-R）、Janus蛋白酪氨酸激酶2（JAK2）、信号转导和转录激活子3 （STAT3）及细胞因子信号转导抑制因子3（SOCS3）的蛋白表达。结果 高脂高胆固醇喂养明显升高小鼠体重、脂重和血清胆固醇水平;与高脂高胆固醇组比较,亮氨酸组小鼠体重、脂重和血清胆固醇水平明显下降;与对照组比较,高脂高胆固醇组小鼠血清瘦素水平明显升高[（7.14±2.44）ng/mL,]（P<0.01）;与高脂高胆固醇组比较,1.5%、3.0%亮氨酸组小鼠瘦素水平[分别为（4.21±2.37）、（4.24±2.22）ng/mL]明显降低（P<0.01）;与对照组比较,高脂高胆固醇组小鼠睾周脂肪组织中Ob-R蛋白表达下调;与高脂高胆固醇组比较,亮氨酸组小鼠睾周脂肪组织中Ob-R、JAK2蛋白表达上调、SOCS3蛋白表达下调。结论 亮氨酸干预可抑制高脂高胆固醇喂养引起的小鼠体重和体脂增加,其机制可能与调节瘦素受体及其下游蛋白JAK2和SOCS3表达、改善瘦素抵抗有关。