低碳水化合物饮食对2型糖尿病患者的影响研究进展

低碳水化合物饮食是目前较为关注的控制糖尿病的饮食方式,包含低碳水化合物高脂肪饮食和低碳水化合物高蛋白质饮食。低碳水化合物饮食通过糖异生和酮生成作用降低葡萄糖的可用性来控制体重和血糖。但这种饮食方式对人体有很多负面影响。本文综述了低碳水化合物饮食对2型糖尿病患者的血管、心肌、肾脏的影响,以及此饮食方式的饮食依从性的研究进展,为低碳水化合物饮食对2型糖尿病患者的影响提供参考。     

膳食中碳水化合物与代谢综合征的研究进展

代谢综合征是心脑血管病、2型糖尿病甚至癌症等重大疾病发病及致死的重要诱因和共同的病理基础。碳水化合物和脂肪的代谢紊乱,在代谢综合征的发生和发展中扮演了重要的角色。目前,大量研究集中于高脂肪的饮食危害及其对代谢综合征的作用,而忽略了饮食中精细碳水化合物比例增加及其摄入量过多对代谢综合征的促进影响。在近几年的研究中,发现碳水化合物摄入与代谢综合征的发生与发展密不可分。故本文对碳水化合物摄入与代谢综合征之间的关系展开综述,为日常饮食健康提供一定的理论指导。     

高糖饮食对果蝇发育和抗氧化能力的影响及其机理研究

为探究高糖饮食对果蝇发育、寿命及抗氧化能力的影响,以果蝇为研究对象,将含有高蔗糖的培养基喂养果蝇,并测定果蝇的寿命、运动能力与抗氧化能力;同时,对高糖组果蝇进行转录组测序,尝试从基因转录水平上探索高糖饮食影响果蝇发育的机理。结果表明,与对照组相比,高糖组雌性、雄性果蝇和雌雄混养果蝇的平均寿命分别缩短了35.01%、43.01%和34.15%,雄性果蝇和雌雄混养果蝇的生存曲线显著低于对照组（P<0.05）。高糖饮食降低了果蝇的化蛹率、羽化率和攀爬能力。高糖组雄性果蝇在生命后期体内T-SOD酶和CAT酶有不同程度的降低,而MDA含量均有所增加。通过转录组测序,发现高糖组果蝇的差异表达基因富集在果蝇发育过程、机体代谢活动调控及应激反应等方面。本研究表明高糖饮食显著降低果蝇的寿命、发育、运动能力及抗氧化能力,为健康饮食提供参考。     

具有特定保健功能的调和油及其市场前景

<正>分析油脂中共轭亚油酸、α-亚麻酸和γ-亚麻酸等特定功能物质。说明特定功能调和油的应用范围及市场前景。油脂是人们日常饮食中不可或缺的一种食物原料,油脂、蛋白质和碳水化合物组成自然界的三大营养成分。随着人们传统保健意识的增强,人们更加热衷于"食补",是日常饮食中必需品,油脂具有重要作用,保健功能被发掘。人体摄入油脂的目的有获     

热量限制的低碳水化合物饮食和膳食纤维对非酒精性脂肪肝影响的研究进展

近年来热量限制的低碳水化合物饮食和膳食纤维干预对肝脏功能的影响被广泛关注,研究发现热量限制的低碳水化合物饮食和高膳食纤维干预在预防和治疗非酒精性脂肪肝方面表现出积极的作用。热量限制的低碳水化合物饮食可以有效降低非酒精性脂肪肝患者体重、BMI和肝脏脂肪病变程度,有效降低AST水平,但是对ALT和脂质代谢相关指标TC、TG、HDL和LDL的影响存在争议。高膳食纤维干预可有效降低AST和ALT水平,改善肝脏功能。热量限制的低碳水化合物饮食改善肝脏功能的机制是减少能量的摄入,降低胰岛素拮抗,防止脂肪的堆积。膳食纤维改善肝脏功能的机制是除降低胰岛素拮抗之外,还可延缓胃排空的时间,改变肠道的渗透性和增加增强肝脏对胰岛素敏感性的短链脂肪酸,从而调节脂质代谢,改善肝脏功能。本文主要综述了热量限制的低碳水化合物饮食、膳食纤维干预对非酒精性脂肪肝患者体重、BMI、肝脏功能的影响,以及改善肝脏功能的机制。     

光照强度和氮源匮乏培养对小球藻细胞生长和细胞组成的影响

本研究考察了不同光照强度和氮源匮乏培养对小球藻细胞生长及其细胞组成的影响。结果表明,随光照强度的增强,小球藻生物量产率和碳水化合物含量可显著提高,而蛋白质含量和油脂含量则呈现缓慢下降趋势;在光照强度为750μmol·m~(-2)·s~(-1)时,小球藻生物量产率、蛋白质产率和碳水化合物产率达最大值,分别为935.6、509.8、256.0 mg·L~(-1)·d~(-1);而光照强度为450μmol·m~(-2)·s~(-1)时,小球藻油脂产率达最大值,为105.0 mg·L~(-1)·d~(-1)。通过氮源匮乏培养来促进小球藻碳水化合物和油脂含量的积累,发现当氮源匮乏培养时间分别为2 d和4 d时,小球藻碳水化合物产率和油脂产率可进一步提高至471.1 mg·L~(-1)·d~(-1)和150.6 mg·L~(-1)·d~(-1)。     

食物中蛋白质和碳水化合物对睡眠影响的研究进展

大量研究表明食物中常量营养素蛋白质和碳水化合物对睡眠有重要影响,但不同的研究所得结果不尽相同,因此尚不完全清楚食物中蛋白质和碳水化合物对睡眠究竟有何影响。本文结合国内外相关研究,对蛋白质和碳水化合物对睡眠的具体影响进行综述,发现高碳水化合物低蛋白质的食物可能有助于促进睡眠,改善睡眠质量。本文旨在从膳食营养素角度出发为改善睡眠提供一定的理论指导。     

膳食干预对高胆固醇血症患者血脂和营养状况的影响

目的:探讨个体化膳食干预对高胆固醇血症患者血脂指标和营养状况的影响。方法:选取2013年6月—2014年12月收入北京友谊医院且诊断为高胆固醇血症的90例患者,膳食干预3个月,使用24 h膳食回顾调查法和食物频度法,分析调查对象每天膳食中热能及各种营养素的摄入量,与中国居民膳食推荐摄入量比较,分析膳食干预前后患者的饮食情况、血脂指标和相关营养指标的变化。结果:与每人每日各类食物适宜摄入量相比,高胆固醇血症患者在膳食干预前,蔬菜、水果、豆类食物的摄入量偏少,肉类、蛋、奶、油脂类食物摄入量偏高,营养素供能比例不适宜,蛋白质和脂肪供能比例偏高,碳水化合物供能比例偏低;与膳食干预前相比,膳食干预后每日谷类食物、肉类、鸡蛋、奶、油脂类的摄入量显著降低,蔬菜、水果、豆类的摄入量显著增加,摄入的总能量显著降低,摄入的蛋白质、脂肪的量及其供能比显著降低,动物蛋白的供能比显著降低,碳水化合物的摄入量及其供能比显著增加);经过膳食干预后,高胆固醇血症患者的血清总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)水平显著降低,血清高密度脂蛋白胆固醇(HDL-C)水平显著増高,患者的体质指数(BMI)显著降低,血清总蛋白(TP)、白蛋白(ALB)、血红蛋白(HGB)与膳食干预前相比差异无统计学意义。结论:高胆固醇血症患者通过改善膳食结构和降低体质指数,可以降低TC、TG、LDL-C等血脂指标,升高HDL-C,其营养状况不会受到影响。     

微生物油脂生产和应用

<正>如微藻、酵母、霉菌和细菌等微生物,已可将碳水化合物、碳氢化合物和普通的油脂为碳源生产油脂和另一些有商业价值的脂质。真核的微藻、酵母霉菌能在它们的体内合成与植物油脂相似的甘油三酯(单细胞油脂,SCO),原核的细菌则合成特殊的脂质,如蜡、聚酯、聚—β—羟丁酸等。 碳源(碳水化合物/碳氢化合物/油脂)→菌体(微藻、酵母、霉菌和细菌)→下游加工(提取,精制等)→微生物油脂(供食用,营养剂或非食用)     

膳食中的谷物比和油脂比例对机体健康的影响

近年来,代谢综合征在中国居民中呈现高发态势,这与中国居民的膳食结构有密切关系。谷物和油脂是中国居民膳食中提供能量的主要物质,其在膳食中所占比例会对机体健康产生重要影响。该文针对膳食中谷物和油脂所占比例不同,就国内外文献进行综述,以期能为更好改善中国居民膳食健康、减少由不良膳食结构引发的代谢综合征提供帮助。     

Bovine milk fatty acid profiles produced by feeding diets containing solin,flax and canola

Fatty acid profiles with emphasis on linoleic, linolenic, oleic, and conjugated linoleic acid (CLA) were compared in milk from dairy cows fed diets containing 3.25% supplemental fat and a control diet containing no supplemented fat. The fat was supplied by either whole ground solin, flax, or canola oilseed. Solin (linola) is a new cultivar of flax that contains 28% linoleic acid in the seed, Twelve multiparous Holstein cows were assigned to one of four dietary treatments. The experimental design was a 4 x 4 Latin square with each period consisting of 16 d for adjustment to the diet followed by a 5-d sampling period. Feed intake, milk yield, milk fat yield, and milk fat percentage were not affected by treatment. Adding solin, flax, or canola oilseed to lactation diets produced the highest proportions of linoleic (C18:2), linolenic (C18:3), and oleic (C18:1) acids, respectively, in the lipid fraction of the milk of the cows consuming these diets. The proportions of C6:0 to C16:1 were depressed in the milk fat of cows fed the oilseed diets, compared with the control diet. Increasing the lactation diet levels of C18:2, by using different oilseeds, increased CLA to 1.5% of milk fatty acids. The content of CLA in milk fatty acids, however, did not increase with the solin-supplemented diet compared with the canola-supplemented diet even though the C18:2 level was higher in the former diet.     

Effect of fat and lactose supplementation on digestion in dairy cows. 1. Nonlipid components

Seven cows, of which five were fitted with rumen and duodenal cannulae, alternately received "milk" diet with 10% fat and 13% lactose, and control diet with 2% fat and no lactose. Both diets were 60% hay. Organic matter and crude fiber digestibilities were not different between milk diet (73.4 and 68.1%) and control diet (74.1 and 70.5%). The quantity of organic matter degraded in the rumen (percent of intake) was higher with control diet (51%) than with milk diet (44%). Ratio of duodenal nonammonia nitrogen to nitrogen intake was higher with milk diet. Both diets gave the same rumen pH. The milk diet increased butyrate and minor volatile fatty acids and decreased acetate proportions. The milk diet increased plasma beta-hydroxybutyrate and decreased plasma acetate. These differences were significant only after feeding. Changes in the characteristics of digestion with milk diet were related more to lactose than to fat. No decrease in fiber digestion was seen with the milk diet despite its high fat content.     

Some natural immunity indices in mice against a background of varied fat and carbohydrate correlations in the diet]

In mice of the SWR, C3HA, CBA/j and non-inbred lines kept on diets with different combinations of carbohydrates and fats some characteristics of the natural immunity (phagocytic activity of leucocytes, bactericidal and lysozyme activity of the blood serum) were studied. It is shown that the proportions of the fatty and carbohydrate components in the diet is of a definite significance for the defensive forces of the organism.     

Effect of rumen-protected methionine and lysine on casein in milk when diets high in fat or concentrate are fed

To examine the effect of supplying methionine and lysine on milk N composition, isoenergetic, isonitrogenous diets containing 50:50 with 3.9% added fat or 25:75 forage to concentrate with no added fat were fed with or without rumen-protected methionine and lysine to four primiparous and four multiparous early lactation (36 d in milk) Holstein cows in two 4 x 4 Latin squares. Diets contained 1.7 Mcal NE1 and were fed for ad libitum intake. Periods were 21 d. Rumen-protected methionine and lysine increased total N and casein N percentage with the 3.9% fat, but did not increase total N and casein N percentage with the diet without fat. Whey N percentage was greater with the no fat than with the 3.9% fat diet. Whey N percentage was not affected by adding amino acids. Nonprotein N percentage was greater for the diet with the 3.9% fat than with no fat. Proportions of casein N or whey N to total N were unaffected by treatments. Adding methionine and lysine to diets did not increase yields of total N and casein N. The 3.9% fat diet increased proportions of long-chain (C18:0 and C18:1) and decreased proportions of short- to medium-chain fatty acids (C8 to C16) in milk fat. Plasma nonesterified fatty acids and triglyceride concentrations were greater with the 3.9% fat as compared to the no fat diet. Methionine and lysine decreased plasma triglyceride concentrations with the 3.9% fat diet. Milk yields, DM intakes, and plasma glucose concentrations were unaffected by treatment.     

Partial replacement of forage with nonforage fiber sources in lactating cow diets. I. Performance and health

Seventy-eight Holsteins were fed for 112 d to evaluate performance and health responses to diets varying in source and concentration of fiber. Three diets based on different carbohydrate feeding strategies were formulated. These diets contained low concentrations of forage and neutral detergent fiber (NDF) (12.6% forage NDF, 19.5% total NDF), adequate NDF and forage (20% forage NDF, 24.8% total NDF), or low forage with additional NDF from cereal byproducts (12.7% forage NDF, 33.4% total NDF). Responses to sodium bicarbonate supplementation (0 or 0.8% of diet DM) were evaluated for each carbohydrate strategy, and bicarbonate improved performance on all diets. Eight cows were used concurrently in a Latin square experiment to evaluate the linearity of milk fat concentration response to increasing concentrations of byproduct NDF in low-forage diets. Considering both trials, cereal byproduct NDF was only 27% as effective as NDF from alfalfa silage in eliciting a milk fat concentration response, which was less than predicted from previous experiments. This difference was not because of the short duration of previous experiments nor because of nonlinearity in the response to byproduct NDF. Low-forage diets fed for 112 d did not result in major health disorders for midlactation cows. However, several indicators suggested that cows fed low-forage, high-NDF diets might be less susceptible to ruminal acidosis than those fed diets containing low forage and low NDF, especially during times of dietary transition. Although the effective fiber value in various feeds is variable and difficult to quantify, the value of byproduct fiber needs to be considered when balancing the carbohydrate fraction of dairy rations.     

The effect of nonstructural carbohydrate and addition of full fat extruded soybeans on the concentration of conjugated linoleic acid in the milk fat of dairy cows

Conjugated linoleic acid (CLA), a naturally occurring anticarcinogen found in dairy products, is a byproduct of incomplete ruminal biohydrogenation of unsaturated fatty acids. Our objective was to determine the effect of nonstructural carbohydrate sources, addition of full fat extruded soybeans as a source of unsaturated fatty acids, and possible interactions on the milk fat content of CLA. Cows (n = 20) were assigned to a 4 x 4 Latin square involving two sources of nonstructural carbohydrate, high starch (corn) or high pectin (citrus pulp), with or without addition of extruded soybeans. Milk yield was not affected by nonstructural carbohydrate source, but milk production was increased by 7.8 to 10.5% with dietary additions of extruded soybeans. Milk fat content did not differ between treatments, but fatty acid composition was affected. Cows fed extruded soybean diets had reduced concentrations of C8 to C16 fatty acids and increased concentrations of octadecenoic acids. Diets with extruded soybeans also resulted in more than a doubling in milk fat concentration and yield of CLA. Nonstructural carbohydrate source had only minor effects on CLA, and there was no interaction with extruded soybeans. Milk fat content of trans-C18:1 and CLA were closely related (r2 = 0.77). However, variation among cows was about threefold for each of the diets and rank order of individual cows differed among diets. Overall, we demonstrated that diet modification can be used to alter CLA content of milk fat, but there was substantial individual cow variation for all diets.     

Conjugated linoleic acid and vaccenic acid in rumen, plasma, and milk of cows fed fish oil and fats differing in saturation of 18 carbon fatty acids

The objective of this study was to examine the effect of feeding fish oil (FO) along with fat sources that varied in saturation of 18 carbon fatty acids (high stearic, high oleic, high linoleic, or high linolenic acids) on rumen, plasma, and milk fatty acid profiles. Four primiparous Holstein cows at 85 d in milk (+/- 40) were assigned to 4 x 4 Latin squares with 4-wk periods. Treatment diets were 1) 1% FO plus 2% commercial fat high in stearic acid (HS); 2) 1% FO plus 2% fat from high oleic acid sunflower seeds (HO); 3) 1% FO plus 2% fat from high linoleic acid sunflower seeds (HLO); and 4) 1% FO plus 2% fat from flax seeds (high linolenic; HLN). Diets were formulated to contain 18% crude protein and were composed of 50% (dry basis) concentrate mix, 25% corn silage, 12.5% alfalfa silage, and 12.5% alfalfa hay. Milk production, milk protein percentages and yields, and dry matter intake were similar across diets. Milk fat concentrations and yields were least for HO and HLO diets. The proportion of milk cis-9, trans-11 conjugated linoleic acid (CLA; 0.71, 0.99, 1.71, and 1.12 g/100 g fatty acids, respectively), and vaccenic acid (TVA; 1.85, 2.60, 4.14, and 2.16 g/100 g fatty acids, respectively) were greatest with the HLO diet. The proportions of ruminal cis-9, trans-11 CLA (0.09, 0.16, 0.18, and 0.16 g/100 g fatty acids, respectively) were similar for the HO, HLO, and HLN diets and all were higher than for the HS diet. The proportions of TVA (2.85, 4.36, 8.69, and 4.64 g/100 g fatty acids, respectively) increased with the HO, HLO, and HLN diets compared with the HS diets, and the increase was greatest with the HLO diet. The effects of fat supplements on ruminal TVA concentrations were also reflected in plasma triglycerides, (2.75, 4.64, 8.77, and 5.42 g/100 g fatty acids, respectively); however, there were no differences in the proportion of cis-9, trans-11 CLA (0.06, 0.07, 0.06, and 0.07 g/100 g fatty acids, respectively). This study further supports the significant role for mammary delta-9 desaturase in milk cis-9, trans-11 CLA production.     

The feeding value of corn distillers solubles for lactating dairy cows

Fifteen Holstein cows (10 multiparous and 5 primiparous) in early to mid lactation (79.3 ± 9.2 d in milk) were used in a multiple 5 × 5 Latin square design with 4-wk periods to evaluate and compare the use of condensed corn distillers solubles (CCDS) and dried distillers grains with solubles (DDGS) in the total mixed ration. The forage portion of the diets was kept constant at 27.5% corn silage and 27.5% alfalfa hay (dry matter basis). Diets were 1) 0% distillers grains products (control); 2) 18.5% DDGS; 3) 10% CCDS; 4) 20% CCDS; and 5) a combination diet of 18.5% DDGS with 10% CCDS. Diets 2 and 3 contained 2% fat from DDGS or CCDS, whereas diet 4 contained 4% fat from CCDS and diet 5 contained 4% fat from the blend of DDGS and CCDS. The diets were balanced to provide 17% crude protein with variation in acid detergent fiber, neutral detergent fiber, and fat concentration. Dry matter intake (21.5 kg/d) was similar for all diets. Milk yield (33.8, 36.2, 35.5, 36.0, and 36.0 kg/d) tended to be greater for diets 2 to 5 than for diet 1, whereas yields of fat (1.04 kg/d), protein (1.02 kg/d), fat percentage (2.94), and protein percentage (2.98) were similar for all diets. Energy-corrected milk (32.2 kg/d) and feed efficiency (1.58 kg of energy-corrected milk/kg of dry matter intake) were similar for all diets. Milk urea nitrogen (15.0, 10.9, 11.1, 11.0, and 11.4 mg/dL) as well as blood urea nitrogen (15.6, 12.5, 14.6, 13.8, and 14.2 mg/dL) were decreased in diets 2 to 5 compared with diet 1. Milk concentrations of long-chain fatty acids as well as polyunsaturated fatty acids were greater and medium-chain fatty acid concentrations were lower for diets 2 to 5 compared with diet 1. Concentrations of cis-9, trans-11 conjugated linoleic acid (CLA; 0.33, 0.68, 0.51, 0.85, and 1.07 g/100 g of fatty acids) as well as trans-10, cis-12 CLA (<0.01, 0.01, <0.01, 0.02, and 0.02 g/100 g of fatty acids) were greater for diets 2 to 5 compared with diet 1. Molar proportions of ruminal acetate decreased and propionate increased for diets 2 to 5 compared with diet 1. The results showed that CCDS is as effective as DDGS in replacing soybean meal and corn grain in the total mixed ration.     

不同配比的荞麦日粮对高胆固醇血症小鼠肠道胆固醇吸收和菌群的影响（网络首发、推荐阅读）

研究不同比例荞麦日粮,对高胆固醇脂血症小鼠肠道胆固醇吸收和排出功能及肠道菌群的影响。小鼠分别饲喂AIN-93M标准饲料空白组,高胆固醇饲料模型组、高胆固醇饲料+荞麦低剂量组、高胆固醇饲料+荞麦高剂量组,饲喂12周。结果显示,不同比例荞麦日粮均能降低血液中胆固醇含量,修复小肠受损结构。相对于模型组,荞麦日粮组能提高小肠的ABCG5/ABCG8（ATP binding cassette transporter subfamily G members 5/8）信使核糖核酸（mRNA）表达量,减少NPC1L1（Niemann-Pick type C 1 like 1）蛋白的mRNA表达量,进而减少小肠对胆固醇的吸收。不同比例的荞麦日粮可以极显著升高小鼠肠ABCA1、SR- B1基因表达,提升肠道中胆固醇的逆向转运。相比模型组,高比例荞麦日粮大幅度促进肠道菌群的丰度,而低比例荞麦日粮对肠道菌群的丰度有负面作用。