Monounsaturated Fat Diet Research Articles

Relationships between features of metabolic syndrome and fatty acid composition of the diet, plasma, and adipose tissue in older adults

The metabolic syndrome (MetS) is a cluster of conditions including central adiposity, dyslipidemia, hypertension, and hyperglycemia. We conducted a study of 142 healthy older adults aged 60–88, examining fat quality as measured by diet history questionnaire, and plasma and adipose fatty acid composition as predictors for components of MetS.Plasma 16:0, 16:3n4, 18:1n9, and 20:1n9 and dietary saturated fat, monounsaturated fat, and cholesterol predict for having MetS. Dietary monounsaturated fat increases, while adipose 16:1n7 and 18:4n3 decrease, in subjects with increasing numbers of MetS features.Adipose 16:0 is correlated with each feature of MetS. Plasma saturated and monounsaturated fatty acids were positively correlated, while plasma polyunsaturated fatty acid composition was negatively correlated, with triglyceride levels.This study demonstrates several important relationships between the features of metabolic syndrome and fatty acid quality in the diet, plasma, and adipose tissue. Further research should be conducted to determine if these relationships are the result of differences in dietary intake or fatty acid metabolism.

The type and quantity of dietary fat and carbohydrate alter faecal microbiome and short-chain fatty acid excretion in a metabolic syndrome ‘at-risk’ population

An obese-type human microbiota with an increased Firmicutes:Bacteroidetes ratio has been described that may link the gut microbiome with obesity and metabolic syndrome (MetS) development. Dietary fat and carbohydrate are modifiable risk factors that may impact on MetS by altering the human microbiome composition. We determined the effect of the amount and type of dietary fat and carbohydrate on faecal bacteria and short chain fatty acid (SCFA) concentrations in people 'at risk' of MetS. A total of 88 subjects at increased MetS risk were fed a high saturated fat diet (HS) for 4 weeks (baseline), then randomised onto one of the five experimental diets for 24 weeks: HS; high monounsaturated fat (MUFA)/high glycemic index (GI) (HM/HGI); high MUFA/low GI (HM/LGI); high carbohydrate (CHO)/high GI (HC/HGI); and high CHO/low GI (HC/LGI). Dietary intakes, MetS biomarkers, faecal bacteriology and SCFA concentrations were monitored. High MUFA diets did not affect individual bacterial population numbers but reduced total bacteria and plasma total and LDL-cholesterol. The low fat, HC diets increased faecal Bifidobacterium (P=0.005, for HC/HGI; P=0.052, for HC/LGI) and reduced fasting glucose and cholesterol compared to baseline. HC/HGI also increased faecal Bacteroides (P=0.038), whereas HC/LGI and HS increased Faecalibacterium prausnitzii (P=0.022 for HC/HGI and P=0.018, for HS). Importantly, changes in faecal Bacteroides numbers correlated inversely with body weight (r=-0.64). A total bacteria reduction was observed for high fat diets HM/HGI and HM/LGI (P=0.023 and P=0.005, respectively) and HS increased faecal SCFA concentrations (P<0.01). This study provides new evidence from a large-scale dietary intervention study that HC diets, irrespective of GI, can modulate human faecal saccharolytic bacteria, including bacteroides and bifidobacteria. Conversely, high fat diets reduced bacterial numbers, and in the HS diet, increased excretion of SCFA, which may suggest a compensatory mechanism to eliminate excess dietary energy.

The effect of a high monounsaturated fat diet on body weight, backfat and loin muscle growth in high and medium-lean pig genotypes

The objective of this study was to evaluate whether the use of a diet rich in oleic acid could have an effect on daily weight gain, backfat and loin muscle (Longissimus thoracis) depth. One hundred and ninety-two barrows and gilts, from two genotypes were fed a grain and soy diet (CONTROL with 28% C18:1) or a similar diet enriched with oleic acid (HO with 43% C18:1, Greedy-Grass OLIVA®). The pigs were housed in 16 pens in groups of 12 according to their sex, diet and genotype. From 75 days of age every three weeks, the pigs were weighed and the backfat and loin muscle depth were ultrasonically recorded (PIGLOG®). The inclusion of the dietary fat had no significant effect on the growth variables nor on the backfat and loin muscle depth measurements taken. However, the barrows resulted in higher live weight and backfat compared to the gilts at the end of the trial. Conversely, the gilts showed higher loin depth. Moreover, York-sired pigs were heavier than Pietrain-sired pigs during the whole trial and showed higher backfat at the last two measurements. Pietrain-sired pigs had higher loin muscle depth at the last measurements. The results of the present study suggest that the addition of a dietary fat into diets aiming at modifying the meat fatty acid profile has no detrimental effects on performance variables, or on backfat and loin muscle growth and thus, no negative economic impact for producers.

The effect of a high monounsaturated fat diet on body weight, backfat and loin muscle growth in high and medium-lean pig genotypes

The objective of this study was to evaluate whether the use of a diet rich in oleic acid could have an effect on daily weight gain, backfat and loin muscle (Longissimus thoracis) depth. One hundred and ninety-two barrows and gilts, from two genotypes were fed a grain and soy diet (CONTROL with 28% C18:1) or a similar diet enriched with oleic acid (HO with 43% C18:1, Greedy-Grass OLIVA®). The pigs were housed in 16 pens in groups of 12 according to their sex, diet and genotype. From 75 days of age every three weeks, the pigs were weighed and the backfat and loin muscle depth were ultrasonically recorded (PIGLOG®). The inclusion of the dietary fat had no significant effect on the growth variables nor on the backfat and loin muscle depth measurements taken. However, the barrows resulted in higher live weight and backfat compared to the gilts at the end of the trial. Conversely, the gilts showed higher loin depth. Moreover, York-sired pigs were heavier than Pietrain-sired pigs during the whole trial and showed higher backfat at the last two measurements. Pietrain-sired pigs had higher loin muscle depth at the last measurements. The results of the present study suggest that the addition of a dietary fat into diets aiming at modifying the meat fatty acid profile has no detrimental effects on performance variables, or on backfat and loin muscle growth and thus, no negative economic impact for producers.

Dietary Monounsaturated Fat in Early Life Regulates IGFBP2: Implications for Fat Mass Accretion and Insulin Sensitivity

The aim of this study was to investigate effects of dietary supplementation with fat or sugar on body composition (BC) and insulin sensitivity (IS) in maturing pigs. Fifty newborn pigs randomized to a control diet or 18% saturated fat (SF), 18% monounsaturated fat (MUF), 18% mixed fat (MF), or 50% sucrose (SUC), from 1 to 16 weeks of age. Outcomes included weight gain, BC (dual energy X-ray absorptiometry, DXA), IS (fasting insulin and hyperinsulinaemic-euglycaemic clamps), fasting Non-Esterified Fatty Acid (NEFA) concentrations, and mRNA expression of genes involved in lipogenesis and IS in skeletal muscle (SM), subcutaneous (SAT), and visceral adipose tissue (VAT). In vitro studies examined direct effects of fatty acids on insulin-like growth factor-binding protein 2 (IGFBP2) mRNA in C2C12 myotubes. While SUC-fed pigs gained most weight (due to larger quantities consumed; P < 0.01), those fed fat-enriched diets exhibited more weight gain per unit energy intake (P < 0.001). Total (P = 0.03) and visceral (P = 0.04) adiposity were greatest in MUF-fed pigs. Whole-body IS was decreased in those fed fat (P = 0.04), with fasting insulin increased in MUF-fed pigs (P = 0.03). SM IGFBP2 mRNA was increased in MUF-fed pigs (P = 0.009) and, in all animals, SM IGFBP2 mRNA correlated with total (P = 0.007) and visceral (P = 0.001) fat, fasting insulin (r = 0.321; P = 0.03) and change in NEFA concentrations (r = 0.285; P = 0.047). Furthermore, exposure of in vitro cultured myotubes to MUF, but not SF, reduced IGFBP2 mRNA suggesting a converse direct effect. In conclusion, diets high in fat, but not sugar, promote visceral adiposity and insulin resistance in maturing pigs, with evidence that fatty acids have direct and indirect effects on IGFBP2 mRNA expression in muscle.

Dietary Intake of Cholesterol Is Positively Associated and Use of Cholesterol-Lowering Medication Is Negatively Associated with Prevalent Age-Related Hearing Loss

We aimed to assess associations between dietary intake of fats (saturated and monounsaturated fats and cholesterol) and certain food groups (butter, margarine, and nuts) with the prevalence, incidence, and progression of age-related hearing loss. We also aimed to investigate the link between serum lipids and cholesterol-lowering medication (statins) and hearing loss. The Blue Mountains Hearing Study is a population-based survey of age-related hearing loss. Hearing loss was measured in 2956 participants (aged ≥50 y) and was defined as the pure-tone average (PTA) of frequencies 0.5, 1.0, 2.0, and 4.0 kHz > 25 dB hearing level (PTA(0.5-4 kHz)). Dietary data were collected using a semiquantitative FFQ. After multivariable adjustment, the likelihood of prevalent hearing loss increased from the lowest (reference) to the highest quartile of dietary cholesterol intake (P-trend = 0.04). Among persons self-reporting statin use (n = 274), a 48% reduced odds of prevalent hearing loss was observed after multivariable adjustment [OR = 0.52 (95% CI = 0.29-0.93)]. Participants in the second and 3rd quartiles of dietary monounsaturated fat intake compared with those in the first quartile (reference) had a significantly reduced risk of hearing loss progression 5 y later [multivariable-adjusted OR = 0.39 (95% CI = 0.21-0.71)] and [OR = 0.51 (95% CI = 0.29-0.91)], respectively. Our results suggest that a diet high in cholesterol could have adverse influences on hearing, whereas treatment with statins and consumption of monounsaturated fats may have a beneficial influence.

Effect of an elevated monounsaturated fat diet on pork carcass and meat quality traits and tissue fatty acid composition from York-crossed barrows and gilts

Fifty-seven York-crossed barrows and gilts were fed either a grain and soy diet (CONTROL with 28% C18:1) or a similar diet enriched with oleic acid (HO with 43% C18:1, Greedy-Grass OLIVA®). There were no interactions between dietary treatment and gender and there were no differences in intramuscular and subcutaneous fatty acid composition between sexes (P>0.05). Similar primal cut yields, composition of major primal cuts, and carcass and meat quality characteristics were found for HO and CONTROL fed pigs. Apart from a few significant but small differences for some fatty acids, intramuscular fatty acid composition was similar for both dietary treatments. Subcutaneous fat from HO fed pigs had a 6.9% increase in total monounsaturated fatty acids and a 9.3% reduction in total polyunsaturated fatty acids (P<0.05) compared with CONTROL fed animals, without adversely affecting carcass quality and producing suitable hams for processing by the meat industry.

Effect of a high monounsaturated fat diet supplemented with antioxidants on dyslipidemia in type 2 diabetes in Saudi Arabia

Dyslipidemia is a common disorder associated with type 2 diabetes and is the major cause of vascular disease. Antioxidants have been shown to improve dyslipidemia. Also, a diet rich in monounsaturated fatty acids (MUFA) has been recommended for diabetic patients. The effect of a high-MUFA diet alone or with antioxidants in diabetic dyslipidemia has not been previously investigated. The aim of this study was to investigate the effect of consuming a high-MUFA diet alone or with a combination of vitamin E and C, or lycopene on dyslipidemia in diabetic patients from Saudi Arabia. Forty eight type 2 diabetic patients participated in an intervention study lasting 20 weeks divided into three 4 week intervals separated by a washout interval. Subjects consumed 35 g/day olive oil throughout the study. After the first 4 weeks, participants took vitamin E (400 mg/day) and vitamin C (1000 mg/day) supplements. After 4 weeks washout, participants consumed 45g tomato paste (12 mg lycopene/day). Fasting blood samples were analyzed for glucose, lipid profile and total antioxidant status at baseline and at the end of each interval. The high-MUFA intake alone resulted in a significant increase only in HDL-cholesterol (p<0.001). Supplementation with vitamin E and C resulted in a decrease in total, and LDL-cholesterol (p<0.001), but not in HDL-cholesterol, or triacylglycerol (TG). Lycopene consumption significantly increased HDL-cholesterol (p<0.001), with the lowest TC/HDL (p=0.002) ratio among intervals. No change in glucose, TG or TG/HDL ratio was observed at any interval. The total antioxidant status was significantly increased following a high-MUFA diet and with vitamin and lycopene supplementations. Supplementation of a high MUFA diet with vitamin E and C, or lycopene indicated a beneficial effect on dyslipidemia in type 2 diabetes.

Acute metabolic effects of high monounsaturated fat diet and conventional diet in healthy men and type 2 diabetic patients

Acute metabolic effects of high monounsaturated fat diet and conventional diet in healthy men and type 2 diabetic patients

Intake of dietary fats and colorectal cancer risk: Prospective findings from the UK Dietary Cohort Consortium

Introduction: Epidemiologic evidence for an association between colorectal cancer (CRC) risk and total dietary fat, saturated fat (SF), monounsaturated fat (MUFA) and polyunsaturated fat (PUFA) is inconsistent. Previous studies have used food frequency questionnaires (FFQ) to assess diet, but data from food diaries may be less prone to severe measurement error than data from FFQ. Methods: We conducted a case–control study nested within seven prospective UK cohort studies, comprising 579 cases of incident CRC and 1996 matched controls. Standardized dietary data from 4- to 7-day food diaries and from FFQ were used to estimate odds ratios for CRC risk associated with intake of fat and subtypes of fat using conditional logistic regression. We also calculated multivariate measurement error corrected odds ratios for CRC using repeated food diary measurements. Results: We observed no associations between intakes of total dietary fat or types of fat and CRC risk, irrespective of whether dietary data were obtained using food diaries or FFQ. Conclusion: Our results do not support the hypothesis that intakes of total dietary fat, SF, MUFA or PUFA are linked to risk of CRC.

The Effects of Macronutrient Intake on Total and High‐molecular Weight Adiponectin: Results From the OMNI‐Heart Trial

Higher levels of the adipocyte-specific hormone adiponectin have been linked to increased high-density lipoprotein (HDL) and lower insulin resistance. This study was conducted to determine the influence of macronutrient intake on adiponectin levels. One hundred and sixty-four pre- and stage-1 hypertensive adults participated in the Optimal Macro-Nutrient Intake Heart (OMNI-Heart) trial, a crossover feeding study originally testing the effects of macronutrients on blood pressure. Participants underwent three 6-week feeding periods: one rich in carbohydrates (CARB), one rich in monounsaturated fat (MUFA), and one rich in protein (PROT), while maintaining body weight. Their median plasma high molecular weight (HMW) and total adiponectin levels were 2.3 and 8.2 microg/ml, respectively, resulting in an average of 27% HMW adiponectin. Both HMW and total adiponectin levels decreased after baseline while the percent HMW adiponectin remained unchanged. Between diets, the MUFA diet maintained a higher level of both HMW and total adiponectin levels than either the CARB (HMW: +6.8%, P = 0.02; total: +4.5%, P = 0.001) or PROT (HMW: +8.4%, P = 0.003; total: +5.6%, P < 0.001) diets. Changes in total adiponectin levels were positively correlated to changes in HDL cholesterol irrespective of diets (Spearman r = 0.22-0.40). No correlation was found between changes in lipids, blood pressure, or insulin resistance by the homeostasis model assessment (HOMAIR). Macronutrient intake has effects on HMW and total adiponectin levels independent of weight loss. A diet rich in MUFA was associated with higher levels of total and HMW adiponectin in comparison to a carbohydrate- or protein-rich diet. Effects seen in adiponectin paralleled those found with HDL cholesterol.

Influence of dietary fatty acid composition and exercise on changes in fat oxidation from a high-fat diet

Acute high-fat (HF) diets can lead to short-term positive fat balances until the body increases fat oxidation to match intake. The purpose of this study was to examine the effects of a HF diet, rich in either mono-unsaturated or saturated fatty acids (FAs) and exercise, on the rate at which the body adapts to a HF diet.(13)C-labeled oleate and (2)H-labeled palmitate were also given to determine the contribution of exogenous vs. global fat oxidation. Eight healthy men (age of 18-45 yr; body mass index of 22 ± 3 kg/m(2)) were randomized in a 2 × 2 crossover design. The four treatments were a high saturated fat diet with exercise (SE) or sedentary (SS) conditions and a high monounsaturated fat diet with exercise (UE) or sedentary (US) conditions. Subjects stayed for 5 days in a metabolic chamber. All meals were provided. On day 1, 30% of energy intake was from fat, whereas days 2-5 had 50% of energy as fat. Subjects exercised on a stationary cycle at 45% of maximal oxygen uptake for 2 h each day. Respiratory gases and urinary nitrogen were collected to calculate fat oxidation. Change from day 1 to day 5 showed both exercise treatments increased fat oxidation (SE: 76 ± 30 g, P = 0.001; UE: 118 ± 31 g, P < 0.001), whereas neither sedentary condition changed fat oxidation (SS: -10 ± 33 g, P = not significant; US: 41 ± 14 g, P = 0.07). No differences for dietary FA composition were found. Exercise led to a faster adaptation to a HF diet by increasing fat oxidation and achieving fat balance by day 5. Dietary FA composition did not differentially affect 24-h fat oxidation.

Carcass and meat quality characteristics and fatty acid composition of tissues from Pietrain-crossed barrows and gilts fed an elevated monounsaturated fat diet

Fifty-one (Landrace *Large White) *Pietrain barrows and gilts were used to compare the effect of a diet rich in oleic acid (HO) by feeding a by-product of the olive industry (Greedy-Grass OLIVA(R): 1.4% growing, 3.8% finishing) or a grain and soy diet (CONTROL) on carcass characteristics, meat quality and fatty acid profile of intramuscular and subcutaneous fat. Gilts had leaner (P<0.05) carcasses with lower fat percentage in major primal cuts, and less (P<0.05) saturated fat compared with barrows with no interaction (P>0.05) between dietary treatment and gender. Source of dietary fat had no effect (P>0.05) on primal cut yields, composition of major primal cuts, or carcass and meat quality characteristics. Intramuscular fat from HO fed pigs had higher (P<0.05) percentage of saturated (SFA) and monounsaturated (MUFA) fatty acids, and lower (P<0.05) polyunsaturated fatty acids (PUFA) and n-6:n-3 ratio compared with CONTROL animals (37.4% vs. 36.8%, 44.7% vs. 40.1%, 17.9% vs. 23.2%, and 18.9 vs. 21.8 ratio, respectively). Subcutaneous fat from pigs fed HO had greater (P<0.05) MUFA percentage, lower (P<0.05) SFA and PUFA percentage, and lower (P<0.05) n-6:n-3 ratio than pigs fed CONTROL diet (51.4% vs. 48.0%, 30.5% vs. 32.9%, 18.1% vs. 20.1%, and 9.83 vs. 11.3 ratio, respectively). Intramuscular fat had higher proportion of SFA and lower of MUFA showing a higher degree of tissue saturation compared with subcutaneous fat. Feeding Greedy-Grass increased MUFA and decreased PUFA proportions in fat depots reducing the risk of production of carcasses that are soft and oily which result in lower technological and processing quality.

Effects of dietary fat modification on skeletal muscle fatty acid handling in the metabolic syndrome

In the metabolic syndrome (MetS), increased fat storage in 'nonadipose' tissues such as skeletal muscle may be related to insulin resistance ('lipid overflow' hypothesis). The objective of this study was to examine the effects of dietary fat modification on the capacity of skeletal muscle to handle dietary and endogenous fatty acids (FAs). In total, 29 men with the MetS were randomly assigned to one of four diets for 12 weeks: a high-fat saturated fat diet (HSFA, n=6), a high-fat monounsaturated fat diet (HMUFA, n=7) and two low-fat high-complex carbohydrate diets supplemented with (LFHCCn-3, n=8) or without (LFHCC, n=8) 1.24 g per day docosahexaenoic and eicosapentaenoic acid. Fasting and postprandial skeletal muscle FA handling was examined by measuring arteriovenous concentration differences across the forearm muscle. [(2)H(2)]-palmitate was infused intravenously to label endogenous triacylglycerol (TAG) and free fatty acids in the circulation and subjects received a high-fat mixed meal (2.6 MJ, 61 energy% fat) containing [U-(13)C]-palmitate to label chylomicron-TAG. Postprandial circulating TAG concentrations were significantly lower after dietary intervention in the LFHCCn-3 group compared to the HSFA group (DeltaiAUC -139+/-67 vs 167+/-70 micromol l(-1) min(-1), P=0.009), together with decreased concentrations of [U-(13)C]-labeled TAG, representing dietary FA. Fasting TAG clearance across forearm muscle was decreased on the HSFA diet, whereas no differences were observed in postprandial forearm muscle FA handling between diets. Chronic manipulation of dietary fat quantity and quality did not affect forearm muscle FA handling in men with the MetS. Postprandial TAG concentrations decreased on the LFHCCn-3 diet, which could be (partly) explained by lower concentration of dietary FA in the circulation.

Effects of a Plant-Based High-Carbohydrate/High-Fiber Diet Versus High–Monounsaturated Fat/Low-Carbohydrate Diet on Postprandial Lipids in Type 2 Diabetic Patients

OBJECTIVETo search for a better dietary approach to treat postprandial lipid abnormalities and improve glucose control in type 2 diabetic patients.RESEARCH DESIGN AND METHODSAccording to a randomized crossover design, 18 type 2 diabetic patients (aged 59 ± 5 years; BMI 27 ± 3 kg/m2) (means ± SD) in satisfactory blood glucose control on diet or diet plus metformin followed a diet relatively rich in carbohydrates (52% total energy), rich in fiber (28g/1,000 kcal), and with a low glycemic index (58%) (high-carbohydrate/high-fiber diet) or a diet relatively low in carbohydrate (45%) and rich in monounsaturated fat (23%) (low-carbohydrate/high–monounsaturated fat diet) for 4 weeks. Thereafter, they shifted to the other diet for 4 more weeks. At the end of each period, plasma glucose, insulin, lipids, and lipoprotein fractions (separated by discontinuous density gradient ultracentrifugation) were determined on blood samples taken at fasting and over 6 h after a test meal having a similar composition as the corresponding diet.RESULTSIn addition to a significant decrease in postprandial plasma glucose, insulin responses, and glycemic variability, the high-carbohydrate/high-fiber diet also significantly improved the primary end point, since it reduced the postprandial incremental areas under the curve (IAUCs) of triglyceride-rich lipoproteins, in particular, chylomicrons (cholesterol IAUC: 0.05 ± 0.01 vs. 0.08 ± 0.02 mmol/l per 6 h; triglycerides IAUC: 0.71 ± 0.35 vs. 1.03 ± 0.58 mmol/l per 6 h, P < 0.05).CONCLUSIONSA diet rich in carbohydrate and fiber, essentially based on legumes, vegetables, fruits, and whole cereals, may be particularly useful for treating diabetic patients because of its multiple effects on different cardiovascular risk factors, including postprandial lipids abnormalities.

Genotype–Phenotype Associations: Modulation by Diet and Obesity

Changes in diet are likely to reduce chronic disorders, but after decades of active research and heated discussion, the question still remains: what is the optimal diet to achieve this elusive goal? Is it a low-fat diet, as traditionally recommended by multiple medical societies? Or a high monounsaturated fat (MUFA) diet as predicated by the Mediterranean diet? Perhaps a high polyunsaturated fat (PUFA) diet based on the cholesterol-lowering effects? The right answer may be all of the above but not for everybody. A well-known phenomenon in nutrition research and practice is the dramatic variability in interindividual response to any type of dietary intervention. There are many other factors influencing response, and they include, among many others, age, sex, physical activity, alcohol, and smoking as well as genetic factors that will help to identify vulnerable populations/individuals that will benefit from a variety of more personalized and mechanistic-based dietary recommendations. This potential could and needs to be developed within the context of nutritional genomics that in conjunction with systems biology may provide the tools to achieve the holy grail of dietary prevention and therapy of chronic diseases and cancer. This approach will break with the traditional public health approach of "one size fits all." The current evidence based on nutrigenetics has begun to identify subgroups of individuals who benefit more from a low-fat diet, whereas others appear to benefit more from high MUFA or PUFA diets. The continuous progress in nutrigenomics will allow some time in the future to provide targeted gene-based dietary advice.

Design of a Mediterranean Exchange List Diet Implemented by Telephone Counseling

A Greek-Mediterranean dietary pattern has two distinct aspects that differ relative to average intakes in the United States: a high intake of monounsaturated fats and a high intake of fruit and vegetables. The purpose of the study was to develop and test an exchange list Greek-Mediterranean diet that could be used in future clinical trials of breast cancer prevention. A total of 69 women, ages 25 to 59 years, were randomized to either continue their own usual diet or follow an intervention diet for 6 months during 2004 through 2005. Intervention goals were to decrease usual fat intakes by about half and to replace those fats with olive oil and other high–monounsaturated fatty acid foods; increase fruit and vegetable intakes to 7 to 9 servings/day, depending on energy intake; and consume at least one serving per day each of culinary herbs and allium vegetables. Registered dietitians provided exchange goals and individualized telephone counseling, and diets were self-selected using a Mediterranean exchange list developed specifically for this study. Changes in diet were assessed by 7-day food records. Results demonstrated that counseling using the Mediterranean exchange list was effective for large dietary changes relative to the nonintervention group. Repeated measures analysis of variance indicated a statistically significant 48% increase in dietary monounsaturated fat with no appreciable change in total fat intake, and a significant increase in fruit and vegetable intake from 4.0 to 8.6 servings/day ( P < 0.05).

One-Year Comparison of a High–Monounsaturated Fat Diet With a High-Carbohydrate Diet in Type 2 Diabetes

OBJECTIVE—The purpose of this study was to compare the effects of high–monounsaturated fatty acid (MUFA) and high-carbohydrate (CHO) diets on body weight and glycemic control in men and women with type 2 diabetes.RESEARCH DESIGN AND METHODS—Overweight/obese participants with type 2 diabetes (n = 124, age = 56.5 ± 0.8 years, BMI = 35.9 ± 0.3 kg/m2, and A1C = 7.3 ± 0.1%) were randomly assigned to 1 year of a high-MUFA or high-CHO diet. Anthropometric and metabolic parameters were assessed at baseline and after 4, 8, and 12 months of dieting.RESULTS—Baseline characteristics were similar between the treatment groups. The overall retention rate for 1 year was 77% (69% for the high-MUFA group and 84% for the high-CHO group; P = 0.06). Based on food records, both groups had similar energy intake but a significant difference in MUFA intake. Both groups had similar weight loss over 1 year (−4.0 ± 0.8 vs. −3.8 ± 0.6 kg) and comparable improvement in body fat, waist circumference, diastolic blood pressure, HDL cholesterol, A1C, and fasting glucose and insulin. There were no differences in these parameters between the groups. A follow-up assessment of a subset of participants (n = 36) was conducted 18 months after completion of the 52-week diet. These participants maintained their weight loss and A1C during the follow-up period.CONCLUSIONS—In individuals with type 2 diabetes, high-MUFA diets are an alternative to conventional lower-fat, high-CHO diets with comparable beneficial effects on body weight, body composition, cardiovascular risk factors, and glycemic control.

Dietary monounsaturated fat activates metabolic pathways for triglyceride-rich lipoproteins that involve apolipoproteins E and C-III

BackgroundDietary monounsaturated fat (MUFA) and complex carbohydrates have different effects on triglyceride-rich lipoprotein (TRL) metabolism. ObjectiveWe hypothesized that apolipoprotein (apo) E and apo C-III might be involved in these dietary effects because of their crucial role in TRL metabolism. DesignTwelve adults consumed, for 3 wk each, 2 isocaloric diets: first a carbohydrate-rich diet (48% complex carbohydrate, 8% MUFAs) and then a MUFA-rich diet (31% complex carbohydrate, 24% MUFAs) 12 mo later. The dietary composition of other macronutrients in the 2 diets was similar. Body weight was kept constant. Postprandial apo B kinetic studies using stable-isotope tracers were performed after each dietary intervention. Multiple VLDL, intermediate-density lipoprotein (IDL), and LDL fractions were prepared on the basis of apo E and apo C-III contents. ResultsThe MUFA diet increased by ≈4–6-fold, the secretion of VLDLs and IDLs containing both apo E and apo C-III (E+CIII+) (P < 0.05). These are TRLs that mostly cleared from the circulation and are minor precursors of LDL. The MUFA diet also decreased by 60% (P < 0.05) the secretion of the TRLs without apo E or apo C-III (major precursors of LDL in plasma) and decreased their flux to LDLs. Total LDL flux did not change because the MUFA diet increased the flux to LDL from E−CIII+ TRLs, a process that requires the removal of apo C-III. In addition, the MUFA diet significantly increased the TRL fractional catabolic rate by 50% and doubled the percentage of TRLs that were cleared rather than being converted to LDLs. ConclusionMUFA intake activates synthetic and rapid catabolic pathways for TRL metabolism that involve apo E and apo C-III and suppresses the metabolism of more slowly metabolized VLDLs and IDLs, which do not contain these apolipoproteins.

Abstract 675: Contrasting Effects of Dietary Carbohydrate Compared to Mono-unsaturated Fat on Hepatic Production of ApoE and ApoC-III Containing VLDL, and Formation of LDL

The effects of substituting dietary carbohydrate (CHO) with mono-unsaturated fat (MUFA) on plasma apoB metabolism were evaluated in 12 adults: 6 with normal and 6 with high plasma triglyceride levels. They consumed for 3 weeks each time a high CHO diet (48% complex CHO, 8% MUFA) and a high MUFA diet (31% complex CHO, 24% MUFA). ApoB100 kinetic studies were performed at the end of each dietary intervention using stable isotope labeling with a bolus and a primed continuous infusion. Multiple VLDL, IDL, and LDL fractions were prepared according to their apoE and apoC-III content. Compared to the CHO diet, the MUFA diet increased the percentage of VLDL and IDL secreted with both apoE and apoC-III (45% on MUFA vs. 14% on CHO, p &lt; 0.01) and reduced the percentage of VLDL and IDL secreted without either apoE or apoC-III (MUFA 19% vs. CHO 40%, p = 0.02). Total liver secretion rates of apoB100 lipoproteins were similar between diets (MUFA 11.6 vs. CHO 11.3 mg·day −1 ·kg −1 , p = NS). The dietary change did not affect the fractional catabolic rates and flux patterns of the lipoproteins. On both diets, VLDL and IDL that had apoE were rapidly cleared from the circulation, limiting LDL formation; whereas lipoproteins that did not have apoE or apoCIII mostly underwent lipolysis with little direct clearance, and were the main precursors of LDL. As a result, increased secretion of VLDL and IDL containing apoE and apoC-III caused by the MUFA diet was associated with higher direct clearance and lower LDL production rates (p = 0.02 vs. CHO), while the CHO diet increased LDL production due to increased secretion of VLDL without apoE or apoC-III. In conclusion, our results reveal a strong dietary effect on the secretion pattern of apoB100 lipoproteins. Substituting dietary complex carbohydrate with mono-unsaturated fat selectively promotes liver secretion of VLDL and IDL containing both apoE and apoC-III while suppressing the secretion of VLDL and IDL without apoE or apoC-III. This leads to significant downstream effects on LDL formation due to differential effects of apoE and apoC-III on apoB lipoprotein metabolism, resulting in enhanced particle clearance and reduced LDL formation with the MUFA diet compared to the CHO diet.