Fatty acid composition of nuts--implications for cardiovascular health

It is well established that, due to their high content of saturated fatty acids (SFA), the intake of meat and meat products is strongly associated with elevated blood cholesterol concentrations and an increased risk of hypertension, diabetes and cardiovascular diseases. Conversely, the intake of foods rich in unsaturated fatty acids, such as those contained in most vegetable fats and oils and oily fish, is associated with improved lipid profiles, a lower potency of intermediate biomarkers of atherosclerosis and lesser incidence of cardiovascular diseases. There are persuasive evidences that dietary substitution of monounsaturated fatty acids (MUFA) or n-6 polyunsaturated fatty acids (PUFA) for SFA lowers blood cholesterol and may have beneficial effects on inflammation, thrombosis, and vascular reactivity. MUFA may have an advantage over PUFA because enrichment of lipoprotein lipids with MUFA increases their resistance to oxidation. Marine n-3 PUFA have a number of anti-atherosclerotic effects, including anti-arrhythmic properties and, at relatively high doses, reduce serum triglycerides. These effects appear to be shared in part by vegetable n-3 PUFA. Nuts are natural foods rich in unsaturated fatty acids; most nuts contain substantial amounts of MUFA, while walnuts are especially rich in both n-6 and n-3 PUFA. Healthy fats in nuts contribute to the beneficial effects of frequent nut intake observed in epidemiological studies (prevention of coronary heart disease, diabetes, and sudden death) and in short-term feeding trials (cholesterol lowering, LDL resistance to oxidation, and improved endothelial function).     

Macadamia nut consumption lowers plasma total and LDL cholesterol levels in hypercholesterolemic men

This study was conducted to assess the cholesterol-lowering potential of macadamia nuts. Seventeen hypercholesterolemic men (mean age 54 y) were given macadamia nuts (40-90 g/d), equivalent to 15% energy intake, for 4 wk. Plasma total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides and homocysteine concentrations and the fatty acid composition of plasma lipids were determined before and after treatment. Plasma MUFA 16:1(n-7), 18:1(n-7) and 20:1(n-9) were elevated after intervention with macadamia nuts. Plasma (n-6) and (n-3) PUFA concentrations were unaffected by macadamia nut consumption. Plasma total cholesterol and LDL cholesterol concentrations decreased by 3.0 and 5.3%, respectively, and HDL cholesterol levels increased by 7.9% in hypercholesterolemic men after macadamia nut consumption. Plasma triglyceride and homocysteine concentrations were not affected by treatment. Macadamia nut consumption was associated with a significant increase in the relative intake of MUFA and a reduced relative intake of saturated fatty acids and PUFA. This study demonstrates that macadamia nut consumption as part of a healthy diet favorably modifies the plasma lipid profile in hypercholesterolemic men despite their diet being high in fat.     

Palmitic and stearic acids similarly affect plasma lipoprotein metabolism in cynomolgus monkeys fed diets with adequate levels of linoleic acid

This study was designed to evaluate whether the exchange of specific saturated fatty acids [SFA; palmitic acid (16:0) for stearic acid (18:0)] would differentially affect plasma lipids and lipoproteins, when diets contained the currently recommended levels of total SFA, monounsaturated fatty acids and polyunsaturated fatty acids (PUFA). Ten male cynomolgus monkeys were fed one of two purified diets (using a cross-over design) enriched either in 16:0 (palmitic acid diet) or 18:0 (stearic acid diet). Both diets provided 30% of energy as fat (SFA/monounsaturated fatty acid/PUFA: 1/1/1). The palmitic acid and stearic acid diets were based on palm oil or cocoa butter (59% and 50% of the total fat, respectively). By adding different amounts of sunflower, safflower and olive oils, an effective exchange of 16:0 for 18:0 of approximately 5% of energy was achieved with all other fatty acids being held constant. Monkeys were rotated through two 10-wk feeding periods, during which time plasma lipids and in vivo lipoprotein metabolism (following the simultaneous injection of (131)I-LDL and (125)I- HDL were evaluated). Plasma triacyglycerol (0.40 +/- 0.03 vs. 0.37 +/- 0.03 mmol/L), plasma total cholesterol (3.59 +/- 0.18 vs. 3.39 +/- 0.23 mmol/L), HDL cholesterol (1.60 +/- 0.16 vs 1.53 +/- 0.16 mmol/L) and non-HDL cholesterol (2.02 +/- 0.26 vs. 1.86 +/- 0.23 mmol/L) concentrations did not differ when monkeys consumed the palmitic acid and stearic acid diets, respectively. Plasma lipoprotein compositional analyses revealed a higher cholesteryl ester content in the VLDL fraction isolated after consumption of the stearic acid diet (P < 0.10), as well as a larger VLDL particle diameter (16.3 +/- 1.7 nm vs. 13.8 +/- 3.6 nm; P < 0.05). Kinetic analyses revealed no significant differences in LDL or HDL transport parameters. These data suggest that when incorporated into diets following current guidelines, containing adequate PUFA, an exchange of 16:0 for 18:0, representing approximately 11 g/(d.10.46 mJ) [ approximately 11 g/(d.2500 kcal)] does not affect the plasma lipid profile and has minor effects on lipoprotein composition. Whether a similar effect would occur in humans under comparable dietary conditions remains to be established.     

Replacing 40% of dietary animal fat with vegetable oil is associated with lower HDL cholesterol and higher cholesterol ester transfer protein in cynomolgus monkeys fed sufficient linoleic acid

This study was designed to evaluate whether replacing approximately 40 g/100 g dietary animal fat with vegetable oil would improve plasma lipids and lipoproteins when diets contained prudent levels of total saturated acid (SFA), monounsaturated acid (MUFA) and PUFA. Using a cross-over design, male Cynomolgus monkeys (n = 10) were fed purified diets containing a mixture of fats. For the diet based on animal fat (AF-diet), approximately 85 g/100 g of the total fat was derived from pork fat, and approximately 40 g/100 g of this was replaced with olive oil for the vegetable oil-based diet (VO-diet). Thus, the fat content of the VO diet comprised 50% pork fat and 35% olive oil. The remaining 15% of the total fat (for both diets) was safflower oil. Both diets provided approximately 30% of total energy (%en) from fat, <10%en SFA and approximately 6-7%en from PUFA. Monkeys were rotated through two 7-wk feeding periods, during which time plasma lipids and lipoproteins were evaluated. Compared with the AF diet, plasma total cholesterol (TC) concentrations tended to be lower ( approximately 10%) after monkeys consumed the VO diet (3.18 +/- 0.83 vs. 3.52 +/- 0.93 mmol/L, P = 0.099), and this was due entirely to a significant 12% reduction in HDL cholesterol (1.53 +/- 0.41 vs. 1.73 +/- 0.47, mmol/L, P = 0.0009). Although plasma lipoprotein compositional analyses revealed no significant differences in either lipoprotein composition or the estimated particle diameters, the measurement of cholesterol ester transfer protein (CETP) using (3)H-cholesterol ester-labeled HDL revealed that the lower HDL cholesterol (HDL-C) when monkeys consumed the VO diet was associated with a 31% increase in transfer (P = 0.04). However, despite the changes in HDL-C, the TC/HDL-C ratio did not differ between monkeys after the two diet treatments. Regression analyses of data from these monkeys revealed a significant correlation between the dietary 16:0/18:2 ratio and plasma HDL-C. These data suggest that within the context of currently recommended prudent diets, it may be possible to manipulate HDL-C beneficially. Whether a similar effect would occur in humans warrants investigation.     

Pork fat and chicken fat similarly affect plasma lipoprotein metabolism in cynomolgus monkeys fed diets with adequate levels of linoleic acid

The effects on plasma lipoprotein metabolism of replacing pork fat (PF) with chicken fat (CF) (formulated as part of currently recommended prudent diets) was evaluated in 10 male cynomolgus monkeys. Monkeys were rotated through three dietary periods, (each of 10-wk duration), during which total cholesterol (TC), triacylglycerol (TG) and HDL-cholesterol (HDL-C) were measured (7, 8 and 9 wk) and in vivo lipoprotein metabolism evaluated (after 9 wk). Initially, all monkeys were fed a high-fat, high-cholesterol reference diet [38% of energy (en) from fat, 18%en saturated fatty acids (SFA), 10%en monounsaturated fatty acids (MUFA), 10%en polyunsaturated fatty acids (PUFA), 0.045 mg cholesterol/kJ diet]. Subsequently, monkeys were rotated through two test diets (30%en fat, SFA/MUFA/PUFA 1:1:1, 0.004-0.005 mg cholesterol/kJ diet), in which 80% of the fat was either PF or CF, with the remaining 20% derived from high-linoleic safflower oil. There was no significant difference between the two test diets for TG, TC, nonHDL-C, HDL-C or the ratio of TC/HDL-C. Lipoprotein composition, LDL apolipoprotein B pool size, fractional catabolic rate and transport rate were also not significantly different when monkeys consumed the two test diets. These data suggest that when incorporated into diets following current guidelines and containing adequate PUFA ( approximately 7-9%en), PF and CF similarly affect plasma lipids.     

Low fat and high monounsaturated fat diets decrease human low density lipoprotein oxidative susceptibility in vitro

Oxidative modification of low density lipoprotein (LDL) is thought to play an important role in the development of atherosclerosis. Some studies have found that LDL enriched in monounsaturated fatty acids (MUFA) are less susceptible to oxidation than LDL enriched in polyunsaturated fatty acids (PUFA). A high MUFA diet is an alternative to a lower-fat blood cholesterol-lowering diet. Less is known about the effects of high MUFA versus lower-fat blood cholesterol-lowering diets on LDL oxidative susceptibility. The present study was designed to evaluate the effects of men and women consuming diets high in MUFA (peanuts plus peanut butter, peanut oil and olive oil) on LDL oxidative susceptibility, and to compare these effects with those of a Step II blood cholesterol-lowering diet. A randomized, double-blind, five-period crossover design (n = 20) was used to study the effects of the following diets on LDL-oxidation: average American [35% fat, 15% saturated fatty acids (SFA)], Step II (25% fat, 7% SFA), olive oil (35% fat, 7% SFA), peanut oil (35% fat, 7% SFA) and peanuts plus peanut butter (35% fat, 8% SFA). The average American diet resulted in the shortest lag time (57 +/- 6 min) for LDL oxidized ex vivo, whereas the Step II, olive oil and peanuts plus peanut butter diets resulted in a lag time of 66 +/- 6 min (P < or = 0.1). The slower rate of oxidation [nmol dienes/(min x mg LDL protein)] observed when subjects consumed the olive oil diet (24 +/- 2) versus the average American (28 +/- 2), peanut oil (28 +/- 2) and peanuts plus peanut butter diets (29 +/- 2; P < or = 0.05) was associated with a lower LDL PUFA content. The results of this study suggest that lower-fat and higher-fat blood cholesterol-lowering diets high in MUFA have similar effects on LDL oxidative resistance. In addition, our results suggest that different high MUFA sources varying in the ratio of MUFA to PUFA can be incorporated into a high MUFA diet without increasing the susceptibility of LDL to oxidation.     

Towards improved fat intake and nutrition for Malaysians

An examination of the fat composition of the diet of a Malaysian urban hostel population obtained by chemical analysis of representative meals prepared by a 7-day rotation menu, revealed both nutritional attributes and limitations when compared against the dietary messages contained in the American Heart Association (AHA) and World Health Organisation (WHO) models. The Malaysian diet supplies 26% kcal i.e. 66 g total fat (51 g vegetable fats, 15 g animal fats) and contains <300 mg cholesterol, which are below the upper limits for these dietary constituents in the AHA and WHO models and conflicts with the perception that Malaysians in general, may be consuming too much fat and cholesterol. The supply of essential fatty acids (EFA), however, appears sub-optimal at 3.2% kcal mainly due to the comparatively low content of both the omega-6 (linoleic acid) and omega-3 [alpha-linolenic, eicosapentaenoate (EPA) and docosahexaenoate (DHA)] fatty acids in the Malaysian diet. The estimated omega-6/omega-3 fatty acid ratio of 10 further reflects an imbalance of these two families of polyunsaturated fatty acids (PUFA), which can be corrected to a ratio of 5 to 7 by moderate increases in the consumption of fish, soyabean-based foods, and pulses and nuts. Considering the current status of knowledge on the health effects of the different families of fatty acids, the ratio of 2:3:1 for the saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and PUFA in the diet is judged to improve fat intake and nutrition in Malaysians. Such a dietary fatty acids ratio can be satisfied by the use of a cooking oil containing 28% SFA, 53% MUFA, and 19% PUFA, which may obtained by the judicious blending of palm olein with MUFA-rich and PUFA-rich vegetable oils. Alternatively, moderate increases in the consumption of marine fish, pulses, nuts, soybean-based foods and their products would also serve the same end.     

Reducing total dietary fat without reducing saturated fatty acids does not significantly lower total plasma cholesterol concentrations in normal males.

Forty-eight healthy male students ate an average American diet (AAD) with 37% of calories from fat and 16% from saturated fatty acids for 3 wk. During the next 7 wk, one-third of the students continued to eat the AAD, one-third switched to a 30%-fat diet with 9% saturated fatty acids (Step 1 diet), and one-third switched to a 30%-fat diet with 14% saturated fatty acids (Sat diet). The Step 1 group had a significant reduction in plasma total cholesterol (TC) (0.36 +/- 0.37 mmol/L) compared with the AAD group (0.07 +/- 0.39 mmol/L) and the Sat group (0.08 +/- 0.25 mmol/L). The Sat group did not differ from the AAD group. Changes in low-density-lipoprotein (LDL) cholesterol paralleled changes in total cholesterol. High-density-lipoprotein cholesterol fell significantly in the Step 1 group (0.11 +/- 0.08 mmol/L) compared with the AAD group. Plasma triglycerides did not differ between groups at the end of the randomized periods. In summary, reduction of dietary fat intake from 37% to 30% of calories did not lower plasma total and LDL cholesterol concentrations unless the reduction in total fat was achieved by decreasing saturated fatty acids.     

The Mediterranean-type diet: is there a need for further modification?

The effects on plasma lipoproteins of four fat-modified diets were assessed in 11 nuns in a contemplative order in the Mediterranean region of Spain. Diet 1 [high polyunsaturated fatty acid (PUFA), low monounsaturated fatty acid (MUFA), low ratio of PUFAs to saturated fatty acids (P:S)] and diet 3 (low PUFA, high MUFA, low P:S) induced significant, directly comparable reductions in total plasma (12% and 13%, respectively) and low-density-lipoprotein (LDL) cholesterol (24% and 19%, respectively). Diet 2 [high PUFA, high MUFA, low saturated fatty acid (SFA), high P:S] induced greater decrements (23% and 30% in total plasma and LDL cholesterol, respectively). Diet 4 (low PUFA, low MUFA, high SFA, low P:S) induced a significant increase in LDL cholesterol of 11%. No significant changes in high-density-lipoprotein cholesterol were observed with these diets. Because the effects of PUFAs and MUFAs are comparable, no recommendations on modifying the habitual, high-MUFA-containing Mediterranean diet need be made other than, perhaps, a reduction in the overall intake of SFAs.     

The cholesterolaemic effects of dietary fats in cholesteryl ester transfer protein transgenic mice.

In order to investigate the role of cholesteryl ester transfer protein (CETP) in the cholesterolaemic response to dietary fats, we analysed plasma lipid profiles of CETP-transgenic and control C57BL/6 mice fed standard chow (AIN-93G; AIN), a low-fat diet, and diets high in butter (saturated fatty acids; SFA), high-oleic acid safflower oil (monounsaturated fatty acids; MUFA), and safflower oil (polyunsaturated fatty acids; PUFA) for 5 weeks. Each group contained four or five mice. There were significant diet and dietxgenotype effects on plasma total cholesterol (TC; and respectively), liver TC ( and respectively), and esterified cholesterol (EC; and respectively); diet effects on plasma triacylglycerol liver free cholesterol and body weight a genotype effect on body-weight gain and a dietxgenotype effect on energy intake In transgenic mice the SFA diet caused significantly higher plasma TC than the PUFA diet In control mice MUFA and PUFA diets, but not the SFA diet, caused significantly higher plasma TC than the low-fat and AIN diets Transgenic mice fed PUFA had lower plasma TC while transgenic mice fed MUFA had lower LDL+VLDL-cholesterol than controls in the same dietary groups. Transgenic mice fed MUFA and PUFA diets also had significantly higher liver TC and respectively) and EC and respectively) than controls fed the same diets. In the present study we showed that: (1) CETP transgenic mice had a cholesterolaemic response to dietary fats similar to that in human subjects; (2) CETP transgenic mice fed PUFA showed significantly lower plasma TC, while those fed MUFA had lower LDL+VLDL-cholesterol than controls; (3) hepatic accumulation of cholesterol, possibly resulting from the combination of the enhanced cholesteryl ester transfer to apolipoprotein B-containing lipoproteins and increased hepatic uptake of cholesterol, may contribute to the cholesterol-lowering effect of MUFA and PUFA in CETP-transgenic mice; (4) CETP may play a role in appetite and/or energy regulation.     

Influence of nutrition on selected metabolic cardiovascular risk factors among female residents of Krakow

The study involved influence of nutritional factors on select anthropometrical and lipid indices (total cholesterol, LDL, HDL) in female residents of Krakow who were voluntarily participating in the investigation. Only women free of diagnosed cardiovascular diseases were included. The study group consisting of 100 women aged 30-65 years, was divided into two groups: pre-menopause (PM, n=47) and after menopause (AM, n=53). The anthropometrical measurements, % of fat tissue - Tanita scale and Body Mass Index (BMI) was calculated. The energy value and the consumption of basic nutrients intake were calculated using 24-hour recalls from the day before the examination. The AM group presented higher anthropometrical and metabolic risk profile: overweight and obesity (BMI-PM = 25.51 +/- 4.16 kg/m2; AM = 28.28 +/- 4.89 kg/m2) and central adiposity type (WC-PM = 81.04 +/- 10.00 cm; AM = 86.46 +/- 11.73 cm); lipids (Total cholesterol-PM = 5.14 +/- 0.87 mmol/l, AM = 5.67 +/- 1.10 mmol/l; LDL-chol-PM = 2.98 +/- 0.90 mmol/l, AM = 3.40 +/- 0.93 mmol/l; HDL-chol-PM = 1.65 +/- 0.39 mmol/l; AM = 1.63 + 0.46 mmol/l). The irregular participation of fatty acids, proteins from plant sources and dietary fibers in daily diet were found (%Energy PM: SFA = 11.66 +/- 4.34, MUFA = 10.91 +/- 4.04, PUFA = 4.76 +/- 2.75, Keys index = 41.89 +/- 14.91; %EnergyAM: SFA = 11.48 +/- 3.86, MUFA = 11.02 +/- 4.12, PUFA = 4.89 +/- 2.92, Keys index = 40.87 +/- 14.4). Women in the AM group represented healthier nutritional behaviors. Results presented indicate that in further study concerning evaluation of nutrients consumption among women the fact of natural menopause should be considered.     

Serum lipid profile and fatty acid composition of erythrocyte phospholipids in children and adolescents with primary hyperlipidemia

This study aimed at characterizing the fatty acid (FA) composition of red blood cell (RBC) phospholipids in children and adolescents with primary hyperlipidemia, and to ascertain potential association with serum lipid profile and dietary factors. At this purpose, 54 probands aged 6–17 years were recruited. Subjects showed a low omega-3 index (eicosapentaenoic acid, EPA?+?docosahexaenoic acid, DHA <4%). Compared to males, females had a trend toward lower levels of total monounsaturated fatty acids (MUFA) and MUFA/saturated fatty acids (SFAs) ratio in RBCs. An inverse relationship between MUFA concentration in RBCs and serum cholesterol or HDL-C/triglycerides ratio was found. Omega-6 polyunsaturated fatty acids (n-6 PUFA) were positively associated to serum HDL-C levels, and inversely to dietary cholesterol. Fiber intake was positively associated with MUFA/SFA ratio. In conclusion, we provide the first experimental data on phospholipid FA composition of RBCs in hyperlipidemic children, showing sex differences and an overall low omega 3-index.     

不同脂肪酸负荷膳食对小鼠胆固醇代谢的影响

目的　为研究脂肪酸对胆固醇代谢可能的分子机制。方法　C5 7小鼠 75只 ,随机分为 5组 ,各组饲以相应配方饲料 6周。结果　与胆固醇膳食 (Chol)相比 ,胆固醇 多不饱和脂肪酸膳食 (Chol PUFA)可增加血清总胆固醇、机体总胆汁酸 (P <0 0 5 ) ,降低肝脏胆固醇 (P <0 0 5 ) ;胆固醇 单不饱和脂肪酸膳食 (Chol MUFA)动物血清总胆固醇不变 ,机体总胆汁酸明显增加 (P <0 0 5 ) ,肝脏胆固醇降低 (P <0 0 5 ) ;胆固醇 饱和脂肪酸 (Chol SFA)膳食可明显增加 (P <0 0 5 )血清总胆固醇和肝脏胆固醇 ,降低 (P <0 0 5 )机体总胆汁酸。此外 ,PUFA、MUFA和SFA均明显降低肝脏胆固醇 7α -羟化酶 (CYP7a1)mRNA和蛋白的表达。结论　膳食脂肪酸可通过CYP7a1调节机体胆固醇内稳态 ,多不饱和脂肪酸和单不饱和脂肪酸可诱导胆固醇转化为胆汁酸进而维持机体胆固醇在较低水平 ,而此过程中产生的大量胆汁酸又可反馈抑制CYP7a1的表达 ;相反 ,饱和脂肪酸可能通过直接抑制或不改变CYP7a1的表达 ,导致膳食胆固醇在体积的堆积     

Adiponectin gene variants are associated with insulin sensitivity in response to dietary fat consumption in Caucasian men

Adiponectin (adipoQ) gene variants have been associated with type 2 diabetes mellitus and insulin resistance. Our aim was to examine whether the presence of several polymorphisms at the adipoQ gene locus (-11391 G > A, -11377 C > G, 45 T > G, and 276 G > T) influences the insulin sensitivity to dietary fat. Healthy volunteers (30 men and 29 women) consumed 3 diets for 4 wk each: an initial period during which all subjects consumed a SFA-rich diet (38% total fat, 20% SFA), followed by a carbohydrate-rich diet (CHO) (30% total fat, 55% carbohydrate) or a monounsaturated fatty acid (MUFA)-rich diet (38% total fat, 22% MUFA) following a randomized, crossover design. After participants consumed each diet, we tested peripheral insulin sensitivity with the insulin suppression test and measured plasma adiponectin concentrations. C/C homozygous men for the -11377 C > G single nucleotide polymorphism (SNP) had a significantly greater decrease in the steady-state plasma glucose concentrations when changing from the SFA-rich (8.95 +/- 0.6 mmol/L) to the MUFA-rich (6.04 +/- 0.31 mmol/L) and CHO-rich (6.35 +/- 0.38 mmol/L) diets than did those carrying the minor G allele (SFA, 6.65 +/- 0.4 mmol/L; MUFA, 6.45 +/- 0.4 mmol/L; CHO, 5.83 +/- 0.3 mmol/L) (P sex x gene x diet interaction = 0.016). These differences did not occur in female participants. Furthermore, C/C men had lower plasma adiponectin concentrations than did C/C women (P sex x gene interaction = 0.015), independently of the dietary fat consumed. None of the variables examined were significantly associated with -11426 A > G, 45T > G, or 276 G > T SNP. In conclusion, C/C homozygous men for the -11377 C > G SNP at adipoQ gene were significantly less insulin resistant after consumption of the MUFA- and CHO-rich diets compared with the SFA-rich diet. This information should help in the identification of vulnerable populations or persons who will benefit from more personalized and mechanism-based dietary recommendations.     

Effect of a diet high in monounsaturated fat from almonds on plasma cholesterol and lipoproteins.

The effect of almonds as part of a low saturated fat, low cholesterol, high-fiber diet was studied in 26 adults (13 men, 13 women). The baseline diet was modified in a similar way for all subjects by limiting meat, fatty fish, high-fat milk products, eggs, and saturated fat. Grains, beans, vegetables, fruit, and low-fat milk products were the foundation of the diet. During the almond diet period, raw almonds (100 mg/day) supplied 34 g/day of monounsaturated fatty acid (MUFA), 12 g/day of polyunsaturated fatty acid, and 6 g/day of saturated fatty acid. Almond oil was the only oil allowed for food preparation. There was a rapid and sustained reduction in low-density lipoprotein cholesterol without changes in high-density lipoprotein cholesterol. This was reflected in a total plasma cholesterol decrease from (means +/- SEM) 235 +/- 5.0 at baseline to 215 +/- 5.0 at 3 weeks, and to 214 +/- 5.0 mg/dl at 9 weeks (p less than 0.001). When the consumption of nuts high in MUFA increases the fat content of the diet, reduction rather than elevation of plasma cholesterol has to be expected, possibly due to the MUFA content of these nuts.     

Gender influence on plasma triacylglycerol response to meals with different monounsaturated and saturated fatty acid content

OBJECTIVE: Both gender and meal fatty acid composition modulate postprandial triacylglycerol (TAG) metabolism, but little information exists on their interaction. We compared postprandial TAG concentrations in men and women after test meals differing in the proportion of monounsaturated (MUFA) and saturated fatty acids (SFA). SUBJECTS: Nine men (body mass index, BMI: 24.5+/-2.3 kg/m(2)) (mean+/-s.d.) and 10 premenopausal women (BMI: 21.2+/-1.7 kg/m(2)), young and healthy, habituated to a relatively high MUFA diet. DESIGN: Plasma responses were studied after subjects consumed two meals, each providing 60 g of fat and 4.7 MJ, on different occasions: one meal was rich in MUFA (MUFA meal: 40 g MUFA; 12 g SFA) and the other meal was rich in SFA (SFA meal: 20 g MUFA; 32 g SFA). The total body and abdominal fat mass were assessed by dual energy X-ray absorptiometry. RESULTS: Fasting plasma TAG concentration did not differ between meals or genders. No gender differences were observed in either total body or abdominal fat mass. The area under the plasma concentration vs time curve was on average 60% higher (P<0.001) in men than women. Repeated measures ANOVA showed a significant effect of meal x time interaction in men (P<0.001) but not in women (P=0.84). In men, maximal plasma TAG occurred at 4 h and was significantly greater after the MUFA meal (2.10+/-0.20 mmol/l) (mean+/-s.e.m.) than after the SFA meal (1.66+/-0.19 mmol/l) (P=0.01). TAG concentration at 5 h was also significantly greater after the MUFA meal. In women, the patterns of TAG responses were identical after the MUFA and SFA meals. CONCLUSIONS: This study provides evidence that gender influences postprandial TAG concentrations when meal fatty acid composition is altered.     

Long-term almond supplementation without advice on food replacement induces favourable nutrient modifications to the habitual diets of free-living individuals

Epidemiological and metabolic studies have shown that regular nut consumption may protect against risk of heart disease and diabetes. None has investigated the effect of adding nuts to a self-selected habitual diet (containing little or no nuts) on dietary patterns. The present study evaluated the impact of long-term almond supplementation in healthy men (n 43) and women (n 38) aged 25-70 years on nutrient profile and nutrient displacement. All subjects were followed for 1 year. During the first 6 months, subjects followed their habitual diets; in the second 6 months, subjects added almonds to their diets. Diets were assessed by seven random 24 h telephone diet recalls during each diet period. On average, the almond supplement was 52 g/d (about forty-two nuts) containing 1286 kJ. When subjects changed from their habitual diet to the almond-supplemented diet, the intakes of MUFA, PUFA, fibre, vegetable protein, alpha-tocopherol, Cu and Mg significantly (P<0.05) increased by 42, 24, 12, 19, 66, 15 and 23% respectively; the intakes of trans fatty acids, animal protein, Na, cholesterol and sugars significantly (P<0.05) decreased by 14, 9, 21, 17 and 13% respectively. These spontaneous nutrient changes closely match the dietary recommendations to prevent cardiovascular and other chronic diseases. Displacement estimates for total energy, total protein, total fat, SFA, MUFA, PUFA, total fibre, Ca, Fe, Mg, P, K, Zn and alpha-tocopherol ranged from 16 to 98%; the estimates for total food weight, carbohydrate, sugars and Se were >245%. A daily supplement of almonds can induce favourable nutrient modifications for chronic disease prevention to an individual's habitual diet.     

High-monounsaturated fatty acid diets lower both plasma cholesterol and triacylglycerol concentrations

BACKGROUND: Low-fat diets increase plasma triacylglycerol and decrease HDL-cholesterol concentrations, thereby potentially adversely affecting cardiovascular disease (CVD) risk. High-monounsaturated fatty acid (MUFA), cholesterol-lowering diets do not raise triacylglycerol or lower HDL cholesterol, but little is known about how peanut products, a rich source of MUFAs, affect CVD risk. OBJECTIVE: The present study compared the CVD risk profile of an Average American diet (AAD) with those of 4 cholesterol-lowering diets: an American Heart Association/National Cholesterol Education Program Step II diet and 3 high-MUFA diets [olive oil (OO), peanut oil (PO), and peanuts and peanut butter (PPB)]. DESIGN: A randomized, double-blind, 5-period crossover study design (n = 22) was used to examine the effects of the diets on serum lipids and lipoproteins: AAD [34% fat; 16% saturated fatty acids (SFAs), 11% MUFAs], Step II (25% fat; 7% SFAs, 12% MUFAs), OO (34% fat; 7% SFAs, 21% MUFAs), PO (34% fat; 7% SFAs, 17% MUFAs), and PPB (36% fat; 8% SFAs, 18% MUFAs). RESULTS: The high-MUFA diets lowered total cholesterol by 10% and LDL cholesterol by 14%. This response was comparable with that observed for the Step II diet. Triacylglycerol concentrations were 13% lower in subjects consuming the high-MUFA diets and were 11% higher with the Step II diet than with the AAD. The high-MUFA diets did not lower HDL cholesterol whereas the Step II diet lowered it by 4% compared with the AAD. The OO, PO, and PPB diets decreased CVD risk by an estimated 25%, 16%, and 21%, respectively, whereas the Step II diet lowered CVD risk by 12%. CONCLUSION: A high-MUFA, cholesterol-lowering diet may be preferable to a low-fat diet because of more favorable effects on the CVD risk profile.     

Should mono- or poly-unsaturated fats replace saturated fat in the diet?

The effects of diets differing in saturated, monounsaturated and polyunsaturated fatty acid composition (SAFA, MUFA and PUFA, respectively) on plasma lipoproteins and factor VIIc were investigated in 28 middle-aged men and women with mild to moderate hyperlipidaemia. The subjects were stabilized on a diet with a total fat content fairly typical of New Zealand, containing approximately 40% energy as fat, before entering a randomized cross-over trial of diets high in PUFA (20% energy; SAFA and MUFA 10% each) or a high MUFA diet (20% energy; SAFA and PUFA 10% each). After 6-week periods on each diet the subjects returned to a high SAFA diet. Body weight and blood pressure remained unchanged during the study. Total and LDL cholesterol, HDL cholesterol and the HDL2 subfraction were significantly lower on both the MUFA and the PUFA diet than on SAFA. However, there were no statistically significant differences in lipoprotein concentrations on the MUFA and PUFA diet. Factor VIIc concentrations were similar on the three diets. The proportion of PUFA in a MUFA diet appears to be a major determinant of the relative lipoprotein response to such a diet. In order to avoid a reduction in HDL-C when replacing SAFA with MUFA it may be necessary to ensure that PUFA does not provide more than about 8% total energy. Thus careful planning is needed to identify the most appropriate foods to replace those rich in SAFA in diets designed to reduce the lipoprotein-mediated risk of coronary heart disease.     

Cholesterol, phytosterol and polyunsaturated fatty acid levels in 1982 and 1957 Japanese diets

The dietary intake of cholesterol, phytosterol and PUFA in Japanese was investigated to obtain information on dietary parameters related to coronary artery disease. Three daily menus for both 1957 and 1982 were prepared based on the daily per capita consumption of foods and nutrient intakes from national surveys. From 1957 to 1982, the average daily intake of cholesterol rose 2.1-fold from 183 to 376 mg while that of phytosterol remained at about 373 mg. Daily intakes of total fatty acid (19.2 g), PUFA (7.3 g), MUFA (5.8 g) and SFA (6.1 g) in 1957 increased in 1982 to 48.7 g, 11.9 g, 19.5 g and 17.3 g, respectively. The ratio of PUFA/SFA decreased to 56% from 1.23 in 1957 to 0.69 in 1982 and the PUFA/MUFA ratio also decreased to 48%. The PUFA/cholesterol ratio was lower in 1982 (31.8) than in 1957 (42.6), and the decrease in the phytosterol/cholesterol ratio to 46% was greater than that in the PUFA/cholesterol ratio (which only fell to 75% of the 1957 value). Thus, comparison of the 1982 and 1957 intakes indicated the increase in risk factors, cholesterol and SFA intake, and the decrease in the ratio of PUFA/SFA in the Japanese population during the past few decades.