Effect of dietary fat and vitamin E on mouse lung lipids.

To examine the effect of dietary fat on lung lipids, male weanling mice (CD-1 strain) were fed purified diets containing 5% stripped lard or corn oil and kept in chambers supplied with air filtered free of airborne bacteria. Vitamin E was fed at 0, 10.5 or 105 mg dl-alpha-tocopheryl acetate/kg diet. Dietary fat and vitamin E (0 or 10.5 mg/kg) had no significant effects on the lung levels of triacylglycerol (TG) or phospholipid (PL) molecular species through 4 weeks of intake. Alterations in lung fatty acid composition were followed through 6 weeks of intake at 0, 10.5 and 105 mg vitamin E/kg diet. Vitamin E, at all levels of supplementation, had no significant effect on mouse lung fatty acid composition. Saturated fatty acids of the lung also showed little alteration by diet, but feeding the lard diet significantly elevated oleic and palmitoleic acids. In mice fed the corn oil diet the levels of linoleic acid (18:2) were twice those of lard-fed mice, and arachidonic acid (20:4) was elevated by 15.8%. The diet elevated the mean peroxidizability index (PI) on lung tissue in corn oil-fed mice.     

膳食脂肪对高血压人群血脂水平的影响

目的 探讨改善膳食脂肪摄入情况对血脂的影响。方法 对营养健康教育前后高血压患者的膳食脂肪摄入情况及血脂水平进行测定分析。结果 基线调查表明人群膳食脂肪及胆固醇摄入量过高,脂肪供能比占总热能的30％以上;血清总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白（LDL－L）水平偏高。相关分析表明,体质指数（BMI）和饱和脂肪酸（SFA）与血清TC、TG、LDL－C呈正相关;高密度脂蛋白（HDL－C）／TC与BMI、SFA呈负相关,而与单不饱和脂肪酸（MUFA）呈正相关。进行社区营养干预后,干预组脂肪供能比小于总热能的30％,与对照组相比及自身干预前后比较差异均有显著性,胆固醇摄入量有下降趋势;干预组人群血脂TC、LDL－C水平显著降低。结论 研究结果提示减少膳食脂肪和胆固醇摄入量,适当增加单不饱和脂肪酸摄入对高血压人群降低血脂水平,控制血压是有效的。     

Effects of dietary fiber, carbohydrate, lipid and protein levels on serum and liver lipids in rats

Response-surface regression analysis was used to study dietary levels of fiber, carbohydrate, lipid and protein to minimize serum and liver cholesterol and triglyceride levels and maximize serum high-density lipoprotein-cholesterol levels of male weanling rats. Because the dietary components were not statistically independent, they were studied in combinations of three variables. The three-variable combinations were the most useful in locating the desired maximum or minimum lipid responses in terms of the proportions of the dietary components. These analyses indicated that dietary carbohydrate, lipid and protein were better than dietary fiber for predicting the serum and liver lipid response levels. Response-surface contours and three-dimensional plots were developed for each lipid response except serum triglycerides, which were not predictable. The contours and three-dimensional plots were used to help determine those combinations of the diet components that would produce the desired maximum or minimum lipid responses. The statistical analyses indicated that the desired lipid response levels could be attained with a diet consisting of 3-5% neutral detergent bran fiber, 6-10% lipid, 54-55% carbohydrate, 26-30% protein and 4.7% vitamins and minerals.     

Effect of dietary lipids and vitamin E on in vitro lipid peroxidation in rat liver and kidney homogenates

Rats were fed for 5 wk 10% (wt/wt) menhaden oil (MO) or a 10% corn oil-lard (COL) mixture (1:1) in diets with a low vitamin E content (less than or equal to 5 mg/kg) or supplemented with d-alpha-tocopheryl succinate to a total of 30 or 150 mg per kg. Thiobarbituric acid-reactive substances (TBARS), conjugated dienes (CD), hexanal and total volatiles (TOV) were measured in tissue homogenates incubated at 37 degrees C for 1 h in the absence (uninduced) and presence of 15 microM ferrous sulfate (induced). The fatty acid composition of liver and kidney reflected that of dietary lipids. For uninduced peroxidation, there was in general a significant inverse correlation of TBARS, CD and TOV with the log of dietary vitamin E content for liver and kidney from rats fed either lipid. For induced peroxidation, the inverse correlation was significant for liver, but not for kidney, from rats fed either lipid. The correlation was generally higher for liver and kidney from rats fed COL than for tissues from rats fed MO. Vitamin E was thus a more effective antioxidant for liver than for kidney regardless of the dietary lipid, and for liver and kidney from rats fed COL than from rats fed MO. Dietary MO enhanced tissue susceptibility to both peroxidation systems. A simulation model developed to mimic the experiments showed good correlations between experimental data and simulated values.     

Effect of dietary supplementation of vitamin E on serum lipids and lipoproteins in rabbits fed a cholesterolemic diet.

The effect of dietary supplementation of vitamin E on serum cholsterol, triglycerides, lipoproteins and lipoprotein composition was studied in rabbits fed a one per cent cholesterol diet for a period of twelve weeks. Vitamin E supplemented animals were found to maintain significantly lower concentrations of serum cholesterol, triglycerides and very low density lipoproteins (d less than 1.006). The difference in the serum lipid content was mainly in the very low density lipoproteins of d less than 1.006. The possibility of an increased clearance of chylomicron remnants and decreased inhibition of extrahepatic lipoprotein lipase in hypercholesterolemic rabbits as a result of vitamin E supplementation is discussed in the light of the results obtained.     

Effects of oleic-rich and omega-3-rich diets on serum lipid pattern and lipid oxidation in mildly hypercholesterolemic patients

AIMS: To evaluate which dietary fat elicits the best response in terms of plasma lipids, lipoproteins, and oxidative processes. METHODS: After a 4-week run-in period, 14 mildly hypercholesterolemic subjects were fed two balanced diets for 6-week periods. During the first intervention period, patients received a monounsaturated fatty acid (MUFA)-enriched diet (olive oil diet). During the second period this diet was supplemented by n-3 polyunsaturated fatty acids (PUFAs) (n-3 diet). RESULTS: After the olive oil diet, a significant decrease in total serum cholesterol (-8.54%, P<0.01), and in apolipoprotein B (Apo B) (-10.0%, P<0.01) was observed. With the addition of n-3 fatty acids no further significant changes in serum lipid concentrations were found. However, the n-3 diet was followed by an increase in lipoperoxides in isolated native low-density lipoprotein (LDL) (67.23%, P<0.01). CONCLUSIONS: A beneficial effect on the serum lipid pattern was observed with the olive oil-enriched diet. The lack of further beneficial modifications on blood lipids and lipoproteins and the increase in the oxidative susceptibility of LDL observed after the addition of n-3 PUFA to the olive oil diet does not favor the use of this diet in hypercholesterolemic patients if it is not associated with a high intake of antioxidants.     

Effects of serum lipid concentrations and smoking and drinking habits on serum vitamin A and E levels

Serum retinol and tocopherol concentrations in 419 males and 478 females, aged 10 to 49 years, were determined by an HPLC method. Then their relationships to serum lipid concentrations and smoking and drinking habits were examined. Retinol levels were higher in males than in females but tocopherol showed little difference by sex. The sex differences in age-related serum levels of retinol and triglyceride (TG) were similar to those of tocopherol and total cholesterol (TC), respectively. Retinol had a significant correlation with TC and TG, with coefficients of 0.20-0.29 (p less than 0.001). These were smaller than those of tocopherol (R = 0.32-0.52, p less than 0.001) both in males and females, suggesting that it had a higher susceptibility to factors other than serum lipids than tocopherol did. Both the retinol and tocopherol levels were significantly higher in the groups with smoking and drinking habits than in the groups without them among the males aged 30 years and over. Furthermore, the retinol level was positively dependent on the daily consumption of both cigarettes and alcohol, whereas tocopherol was dependent on the consumption of alcohol. Multiple regression analysis showed that smoking and drinking habits had statistically significant effects on the serum retinol level independent of other factors and that their effects were greater than those of TC and TG. Tocopherol was affected most by TC and TG and then by drinking habit. Less significant but similar results were obtained for the females of the same age group.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of dietary calcium and vitamin D3 on tumor promotion in mouse skin

The effects of low, adequate, and supplemental intake of calcium and vitamin D3 on 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) skin tumor promotion were examined. Administration of the experimental diets was started one week before the first TPA application to the 7,12‐dimethylbenz[a]anthracene‐initiated dorsal skin of female Sencar mice. Neither dietary calcium in a range from 0.15% to 2.0% of the diet as calcium carbonate nor vitamin D3 ranging from 200 to 4,000 IU/kg diet resulted in modulation of the skin papilloma response in terms of incidence, number per mouse, or size distribution of tumors. There were also no effects of the varied levels of calcium or vitamin D3 on mouse body weights, serum calcium, or TPA induction of epidermal ornithine decarboxylase activity. These results indicate that dietary administration of a wide range of doses of calcium or vitamin D does not alter the serum calcium levels and, therefore, does not appear capable of altering skin tumor promotion. These results are in contrast to reports that demonstrate antineoplastic activity for both calcium ion and active hormonal vitamin D, either in control of epidermal cell proliferation and/or differentiation or in inhibition of carcinogenesis.     

Effects of dietary calcium and vitamin D3 on tumor promotion in mouse skin.

The effects of low, adequate, and supplemental intake of calcium and vitamin D3 on 12-O-tetradecanoylphorbol-13-acetate (TPA) skin tumor promotion were examined. Administration of the experimental diets was started one week before the first TPA application to the 7,12-dimethylbenz[a]anthracene-initiated dorsal skin of female Sencar mice. Neither dietary calcium in a range from 0.15% to 2.0% of the diet as calcium carbonate nor vitamin D3 ranging from 200 to 4,000 IU/kg diet resulted in modulation of the skin papilloma response in terms of incidence, number per mouse, or size distribution of tumors. There were also no effects of the varied levels of calcium or vitamin D3 on mouse body weights, serum calcium, or TPA induction of epidermal ornithine decarboxylase activity. These results indicate that dietary administration of a wide range of doses of calcium or vitamin D does not alter the serum calcium levels and, therefore, does not appear capable of altering skin tumor promotion. These results are in contrast to reports that demonstrate antineoplastic activity for both calcium ion and active hormonal vitamin D, either in control of epidermal cell proliferation and/or differentiation or inhibition of carcinogenesis.     

Effects of dietary lipids on immune function in a murine sensitisation model

We have tested the effect of dietary fatty acids on aspects of innate and specific adaptive T helper (Th) 1- and Th2-driven immune responses in a murine sensitisation model using dinitrochlorobenzene as sensitiser. Six groups of fifteen BALB/c mice were fed diets containing 30 % fat (by energy) for 8 weeks. Diets were rich in saturated fatty acids, n-6 polyunsaturated fatty acid (PUFA), or n-3 PUFA, each at a sufficient (11, 35 and 68 mg/kg) and a supplemented vitamin E level (1028, 1031 and 1030 mg/kg respectively). Feeding n-6 PUFA marginally decreased % phagocytosing cells at the low vitamin E level, but had no other effects on immune function. The n-3 PUFA diets decreased production of prostaglandin E2 while increasing oxidative burst and tumour necrosis factor alpha production. In addition adaptive Th1-driven responses (immunoglobulin, Ig)G2a, IgG2b, interferon-gamma:interleukin 4) were decreased, whereas Th2-driven and mucosal immune responses were increased (IgE) or unaffected (IgG1, IgA). Combination with high levels of alpha-tocopherol did not affect the reduced prostaglandin E2 production, augmented the increase of tumour necrosis factor alpha production and tended to ameliorate the selective suppressive effects of n-3 PUFA on certain Th1-driven effects (interferon-gamma:interleukin 4 ratio and IgG2a levels). We conclude that the sensitisation model appears useful for application in nutrition research. It allows a broad assessment of the effects of dietary intervention on various aspects of immune responsiveness, and as such provides a valuable model to assess, characterise and rank effects of foods and/or nutrients on a range of immune functions, including Th1-Th2 polarisation.     

饮食n-3脂肪酸对小鼠脑脂类中多不饱和脂肪酸构成的影响

【目的】观察饮食鱼油n-3多不饱和脂肪酸(n-3 PUFAs)对脑内不同脂类中PUFAs构成的影响。【方法】使用C57BL/6J雌性小鼠,在胎儿期和幼年期分别给予不同种类高脂饲料(18%脂肪,供能比为36%)喂养-高脂豆油饲料、高脂鱼油饲料和高脂豆油:鱼油(5∶1)混合饲料,以正常饲料(6%脂肪来自豆油,供能比为12%)为对照,时间为4个月。采用薄层层析分离脑组织中各主要脂类成份,然后采用甲酯化-气相色谱分析对各脂类成份中的脂肪酸进行测定。【结果】鱼油饲料喂养改变了小鼠脑内主要脂类中PUFAs的构成。在磷脂中,虽然5种PUFAs在各饲料组之间差异均无显著性(P>0.05),但二十二碳六烯酸(DHA)/花生四烯酸(AA)(1.94±0.41)以及n-3/n-6 PUFAs比值(2.31±0.75)在鱼油组较其它三组显著升高(P<0.05);在甘油一和二酯中,与豆油组相比,鱼油组和豆油:鱼油混合组LA含量(0.31±0.09%,0.65±0.58%)降低,而鱼油组DHA/AA(2.60±1.66)以及n-3/n-6 PUFAs比值(2.31±0.75)升高(P<0.05);在甘油三酯中,与豆油组相比,鱼油组和豆油:鱼油混合组AA含量(1.62±0.53%,1.12±0.36%)和EPA含量(0.98±0.58%,1.34±0.31%)显著降低,而DHA/AA比值(1.14±0.21,1.46±0.58)升高(P<0.05),但DHA含量在三组之间无差异(P>0.05);在游离脂肪酸中,5种PUFAs在各饲料组之间无差异(P>0.05)。【结论】饮食鱼油n-3 PUFAs摄入增多虽然不影响脑内DHA的聚积,但改变了DHA/AA以及n-3/n-6PUFAs的比值。甘油酯类可能是脑摄取、聚积DHA的主要直接来源之一。     

Effects of saturated, monounsaturated, and omega-6 polyunsaturated fatty acids on plasma lipids, lipoproteins, and apoproteins in humans

The effects of dietary fats on plasma cholesterol, serum lipoproteins, and apoproteins (Apo), A-1, B, and CIII were studied. Twelve men consumed three different cholesterol-free formula diets in which polyunsaturated and saturated fats were partially substituted (20% of calories) for monoenoic fats with a constant of 40% of calories from fat. Total cholesterol and low-density lipoprotein cholesterol dropped from base-line values of 166 and 103 to 133 and 81 mg/dl (sat), 127 and 71 mg/dl (mono), and 123 and 65 mg/dl (poly), respectively. High-density lipoprotein cholesterol changed very little from base-line values of 46 to 40 mg/dl (sat), 45 mg/dl (poly), and 43 mg/dl (mono). The plasma concentrations of ApoB declined from base-line values of 80.3 mg/dl to 54.6 mg (mono), 51.8 mg (poly), and 59.6 mg (sat) while Apo CIII and Apo AI did not show any changes. This study demonstrates that: 1) changes in dietary fat affect serum lipids, lipoproteins, and apoproteins even when consumed on a cholesterol-free diet, and 2) omega-6 polyunsaturated fat lowers low-density lipoprotein cholesterol, total cholesterol, and ApoB to a greater extent than monounsaturated or saturated fat, 3) consumption of a cholesterol-free formula diet results in significant decreases in the concentrations of total and low-density lipoprotein cholesterol in plasma when compared to values obtained on a mixed food home diet containing approximately 300 mg cholesterol/day.