Effects of a National Cholesterol Education Program Step II Diet on apolipoprotein A-IV metabolism within triacylglycerol-rich lipoproteins and plasma

The distinct metabolism between large and small HDL indicates unique origins of human apolipoprotein A4

Apolipoprotein A4's (APOA4's) functions on HDL in humans are not well understood. A unique feature of APOA4 is that it is an intestinal apolipoprotein secreted on HDL and chylomicrons. The goal of this study was to gain a better understanding of the origin and function of APOA4 on HDL by studying its metabolism across 6 HDL sizes. Twelve participants completed a metabolic tracer study. HDL was isolated by APOA1 immunopurification and separated by size. Tracer enrichments for APOA4 and APOA1 were determined by targeted mass spectrometry, and metabolic rates were derived by compartmental modeling. APOA4 metabolism on small HDL (alpha3, prebeta, and very small prebeta) was distinct from that of APOA4 on large HDL (alpha0, 1, 2). APOA4 on small HDL appeared in circulation by 30 minutes and was relatively rapidly catabolized. In contrast, APOA4 on large HDL appeared in circulation later (1-2 hours) and had a much slower catabolism. The unique metabolic profiles of APOA4 on small and large HDL likely indicate that each has a distinct origin and function in humans. This evidence supports the notion that APOA4 on small HDL originates directly from the small intestine while APOA4 on large HDL originates from chylomicron transfer.

Vegetarianism as a protective factor for asymptomatic colonic diverticulosis in Asians: a retrospective cross-sectional and case-control study

Background/Aims

Dietary fiber intake is considered a protective factor for diverticular disease such as diverticulitis. However, evidence for an inverse connection between dietary fiber consumption and asymptomatic colonic diverticulosis is lacking. Specifically, few studies have investigated this subject in Asians with different presentations of diverticulosis. Therefore, we assessed the protective effects of a vegetarian diet for asymptomatic colonic diverticulosis in Buddhist monks who are obligatory vegetarians for spiritual reasons compared with the general population.

Methods

A retrospective, cross-sectional, case-control study was conducted in age- and sex-matched Buddhist monks and the general population who underwent colonoscopy for screening at a Korean health promotion center from August 2005 to June 2018. We compared the prevalence of asymptomatic diverticulosis between the 2 groups using a self-administered questionnaire.

Results

In this study, a total of 1,316 individuals were included (Buddhist monks of 658 and general population of 658) with a mean age of 52.6±9.5 years. The prevalence of asymptomatic diverticulosis in Buddhist monks was lower compared with the general population (6.7% [44/658] vs. 10.8% [71/658], P=0.008). Buddhist monks had a higher rate of high body mass index (BMI) and metabolic syndrome. By a multivariate regression analysis model, a nonvegetarian diet (odds ratio [OR], 1.82; 95% confidence interval [CI], 1.21–2.72, P=0.004), old age (OR, 4.53; 95% CI, 1.36–15.12; P=0.014), male sex (OR, 1.91; 95% CI, 1.28–2.85; P=0.002), and a high BMI (OR, 1.50; 95% CI, 1.01–2.23; P=0.047) were independent predictors of asymptomatic diverticulosis. Moreover, a nonvegetarian diet was associated with both right-sided and left-sided diverticulosis.

Conclusions

A nonvegetarian diet may increase a risk of asymptomatic colonic diverticulosis in Asians.

Development and Validation of Bioelectrical Impedance Analysis Equations in Adolescents with Severe Obesity

BACKGROUND

Body mass index measures excess weight for size, and does not differentiate between fat mass (FM) and fat-free mass (FFM). Bioelectrical impedance analysis (BIA) is most commonly used to assess FM and FFM as it is simple and inexpensive. Variables from BIA measurements are used in predictive equations to estimate FM and FFM. To date, these equations have not been validated for use in adolescents with severe obesity.

OBJECTIVES

In a cohort of adolescents with severe obesity (SO), a BMI ≥ 120% of the 95th percentile, this study aimed to 1) derive a BIA predictive equation data from air displacement plethysmography (ADP) measurements; 2) reassess the equation in a second validation cohort; and 3) compare the accuracy of existing body composition equations.

METHODS

Adolescents with SO were assessed using ADP and BIA. FM values derived from ADP measurements from the first cohort (n = 27) were used to develop a BIA predictive equation (i.e., Hamilton). A second cohort (n = 65) was used to cross-validate the new and 9 existing BIA predictive equations.

RESULTS

Ninety-two adolescents (15.8 ± 1.9 y; BMI: 46.1 ± 9.9 kg/m2) participated. Compared with measured FFM using ADP: 1) the Lazzer, Hamilton, Gray, and Kyle equations were without significant bias; 2) the Hamilton and Gray equations had the smallest absolute and relative differences; 3) the Kyle and Gray equations showed the strongest correlation; 4) the Hamilton equation most accurately predicted FFM within ± 5% of measured FFM; and 5) 8 out of 9 equations had similar root mean squared prediction error values (6.03-6.64 kg).

CONCLUSION

The Hamilton BIA equation developed in this study best predicted body composition values for groups of adolescents with severe obesity in a validation cohort.

Assessment of the therapeutic potential of hesperidin and proteomic resolution of diabetes-mediated neuronal fluctuations expediting Alzheimer’s disease

Alzheimer’s disease (AD) has been proposed as type III diabetes mellitus. Prognosis and early stage diagnosis of AD is essentially required in diabetes to avoid extensive irreversible neuronal damage.

Patient with hypertriglyceridemia, type 2 diabetes, and chronic kidney disease treated with atorvastatin and omega-3 Fatty Acid ethyl esters

This is a case report that describes a 67-year-old woman with mixed hyperlipidemia and diabetic nephropathy. She was initially prescribed a combination of simvastatin plus gemfibrozil by her general practitioner (GP). When referred to our cardiovascular unit, we further diagnosed the patient to have mixed hyperlipidemia and rhabdomyolysis. Because of concerns with her chronic kidney disease (CKD), we temporarily stopped all her drug treatments and started insulin treatment for her type 2 diabetes (T2D). A month later when her T2D was stabilised, we prescribed atorvastatin and an omega-3 fatty acid ethyl ester supplement to treat her hypertriglyceridemia. Within two months her blood lipids were within the recommended range. In patients with stage 3–5 CKD, it is not advisable to prescribe the fibrate gemfibrozil, particularly in combination with a statin that is metabolised predominantly in the kidneys. To minimise adverse events without compromise on efficacy, we used a combination of omega-3 fatty acid ethyl esters, which are not metabolised in the kidneys, with a statin that is minimally metabolised in the kidneys for the treatment of her hyperlipidemia.

Effects of Therapeutic Lifestyle Change diets high and low in dietary fish-derived FAs on lipoprotein metabolism in middle-aged and elderly subjects

The effects of Therapeutic Lifestyle Change (TLC) diets, low and high in dietary fish, on apolipoprotein metabolism were examined. Subjects were provided with a Western diet for 6 weeks, followed by 24 weeks of either of two TLC diets (10/group). Apolipoprotein kinetics were determined in the fed state using stable isotope methods and compartmental modeling at the end of each phase. Only the high-fish diet decreased median triglyceride-rich lipoprotein (TRL) apoB-100 concentration (-23%), production rate (PR, -9%), and direct catabolism (-53%), and increased TRL-to-LDL apoB-100 conversion (+39%) as compared with the baseline diet (all P < 0.05). This diet also decreased TRL apoB-48 concentration (-24%), fractional catabolic rate (FCR, -20%), and PR (-50%) as compared with the baseline diet (all P < 0.05). The high-fish and low-fish diets decreased LDL apoB-100 concentration (-9%, -23%), increased LDL apoB-100 FCR (+44%, +48%), and decreased HDL apoA-I concentration (-15%, -14%) and PR (-11%, -12%) as compared with the baseline diet (all P < 0.05). On the high-fish diet, changes in TRL apoB-100 PR were negatively correlated with changes in plasma eicosapentaenoic and docosahexaenoic acids. In conclusion, the high-fish diet decreased TRL apoB-100 and TRL apoB-48 concentrations chiefly by decreasing their PR. Both diets decreased LDL apoB-100 concentration by increasing LDL apoB-100 FCR and decreased HDL apoA-I concentration by decreasing HDL apoA-I PR.

Particle size of LDL is affected by the National Cholesterol Education Program (NCEP) step II diet in dyslipidaemic adolescents

The objective was to determine the effects of the National Cholesterol Education Program (NCEP) step II diet on LDL and HDL particle size in dyslipidaemic adolescents. Forty-four dyslipidaemic adolescents, aged 10–18 years, participated in this case-control study. The control diet was a diet similar to what most Tehranian adolescents eat. NCEP step II diet was a diet with 30 % of energy as total fat, less than 7 % saturated fat, less than 200 mg cholesterol/d, less than 15 % of energy as MUFA and less than 10 % as PUFA. Lipoprotein particle size was the major outcome variable, which was measured after 3 months of intervention. Comparison was made by the repeated measurement ANOVA. The mean BMI was 26·3 (sd4·2) kg/m2. There were no significant changes in weight or physical activity in the two groups during the study. The NCEP diet resulted in higher reduction in total cholesterol ( − 13 (sd4)v.− 2 (sd0·3) mg/dl,P < 0·001) and LDL ( − 9 (sd2)v.3 (sd0·6) mg/dl,P < 0·01), and higher increase in size of the LDL (1·7 (sd0·4)v.0·1 (sd0·4) nanometer,P < 0·001). HDL particle size did not change significantly. NCEP step II diet had a favourable effect on the LDL particle size. The related mechanism needs to be studied in future experimental designs.

Decrease of plasma apolipoprotein A-IV during weight reduction in obese adolescents on a low fat diet

OBJECTIVE

Apolipoprotein (apo) A-IV is an antiatherogenic apolipoprotein, which may be involved in the regulation of food intake. Plasma apoA-IV is elevated in human obesity and apoA-IV polymorphisms have been associated with the extent of obesity. Our aim was to determine the effects of weight loss on plasma apo-IV in obese adolescents and to examine the relation of apoA-IV with the degree of obesity.

DESIGN

Longitudinal intervention study of a low fat hypocaloric diet conducted in a dietary camp.

SUBJECTS

Two groups of obese adolescents (n=47 and n=29), age: 12.7+/-1.7 and 11.7+/-2.6 y, relative body mass index (RBMI): 168+/-24 and 175+/-34%, respectively.

MEASUREMENTS

Plasma total apoA-IV, apoA-I, apoB, plasma distribution of apoA-IV, leptin, lipids, and lipoproteins before and after 3 weeks of weight reduction.

RESULTS

Plasma apoA-IV decreased from 11.5+/-4.1 mg/dl before to 6.7+/-2.2 mg/dl after weight reduction in the first group (P<0.001) and to a similar extent in the second group. The relative amount of lipid-free apoA-IV and apoA-IV associated with apoA-I increased slightly, whereas apoA-IV associated with lipoproteins devoid of apoA-I decreased. ApoA-IV levels before and after weight reduction and the changes in plasma apoA-IV did not independently correlate with RBMI, weight loss, or plasma leptin.

CONCLUSION

Plasma apoA-IV decreases markedly in overweight adolescents undergoing short-term weight reduction. The decrease is not directly related to the degree of weight loss and the mechanisms underlying this reduction remain to be clarified.

Effects of a low-fat vegan diet and a Step II diet on macro- and micronutrient intakes in overweight postmenopausal women

OBJECTIVE

This study investigated the nutrient intake of overweight postmenopausal women assigned to a low-fat vegan diet or a Step II diet.

METHODS

Fifty-nine overweight (body mass index, 26 to 44 kg/m2) postmenopausal women were randomly assigned to a self-selected low-fat vegan or a National Cholesterol Education Program Step II diet in a 14-wk controlled trial on weight loss and metabolism. Nutrient intake, which was measured per 1000 kcal, was the main outcome measure. Statistical analyses included within-group and between-group t tests examining changes associated with each diet.

RESULTS

Consumption of a low-fat vegan diet was associated with greater decreases in fat, saturated fat, protein, and cholesterol intakes and greater increases in carbohydrate, fiber, beta-carotene, and total vitamin A intakes than was a Step II diet. The low-fat vegan group also increased thiamin, vitamin B6, and magnesium intakes more than the Step II group, and both groups increased folic acid, vitamin C, and potassium intakes. If considering only food sources of micronutrients, the low-fat vegan group decreased vitamin D, vitamin B12, calcium, selenium, phosphorous, and zinc intakes compared with baseline. However, with incidental supplements included, decreases were evident only in phosphorous and selenium intakes. No micronutrient decreases were found in the Step II group.

CONCLUSIONS

Individuals on a low-fat vegan or Step II diet should take steps to meet the recommended intakes of vitamin D, vitamin K, folic acid, calcium, magnesium, and zinc. Individuals on a low-fat vegan diet should also ensure adequate intakes of vitamin B12, phosphorous, and selenium.

Dietary mono- and polyunsaturated fatty acids similarly increase plasma apolipoprotein A-IV concentrations in healthy men and women

We investigated the effect of dietary fatty acid composition on plasma apolipoprotein (apo) A-IV concentrations. Plasma apo A-IV concentrations were measured by ELISA in plasma of 48 healthy men and women in a controlled dietary study. First, all participants consumed a 2-wk baseline diet rich in saturated fatty acids (SFA). Then, they were randomly assigned to one of three dietary treatments, which contained refined olive oil [rich in monounsaturated fatty acids (MUFA), n = 17], rapeseed oil [rich in MUFA and alpha-linolenic acid [18:3(n-3)], n = 13], or sunflower oil [rich in (n-6) PUFA, n = 18] as the principal source of fat for 4 wk. The plasma concentrations of apo A-IV increased when subjects consumed the diets rich in unsaturated fatty acids, by 16% or 13.0 mg/L [F((2,76)) = 12.874, P < 0.001 by repeated-measures ANOVA]. The increase was not affected by diet group affiliation, gender or apo A-IV genotype. In conclusion, diets rich in unsaturated fatty acids, independent of the degree of unsaturation, gender and apo A-IV genotype, increase plasma apo A-IV concentrations compared with a baseline diet rich in SFA in healthy men and women.

Therapeutic lifestyle change and Adult Treatment Panel III: evidence then and now

The Third Report of the National Cholesterol Education Program's Adult Treatment Panel (ATP III) has an extensive section on nonpharmacologic therapy for those with abnormal blood lipids. ATP III focused on the high-saturated fat atherogenic diet, obesity, and sedentary lifestyle and recommended a program of therapeutic lifestyle change (TLC). This review discusses several issues, including 1) why ATP III changed from the Step I and Step II diets to TLC; 2) the benefits of keeping trans fatty acid intake low and the addition of viscous fiber and plant stanol/sterol esters to reduce low-density lipoprotein cholesterol beyond that seen with the Step II diet; 3) the de-emphasis on total fat and a sharper focus on the kinds of fat ingested in the new guidelines; 4) the endorsement of regular physical activity and weight loss as important first steps in reversing the unwanted metabolic effects of the metabolic syndrome; and 5) the emphasis of health-promoting aspects of the diet that include, among other things, fish and omega-3 fatty acids. At all stages of TLC, ATP III encourages the referral to registered dietitians or other qualified nutritionists for medical nutrition therapy. TLC and the ATP III guidelines should provide guidance to practitioners who wish to get low-density lipoprotein cholesterol to goal (whether or not drugs are used), prevent or treat the metabolic syndrome, and improve the overall health of the patient.

Identification of factors regulating lipoprotein lipase catalyzed hydrolysis in rats with the aid of monoacid-rich lipoprotein preparations(1)

To identify the substrate specificity and regulatory factors in lipoprotein lipase (LPL) catalyzed hydrolysis of triacylglycerol-rich lipoprotein, monoacid-rich lipoproteins were used to study the kinetic parameters of LPL. Feeding growing rats with diets rich in palmitic acid (16:0), oleic acid (18:1) or linoleic acid (18:2) for 10 days increased the corresponding acid content in the triacylglycerols of the lipoproteins. Force-feeding the monoacid-rich triacylglycerols, particularly 16:0 or 18:1, increased the respective fatty acid content in both chylomicrons and VLDLs. Major apolipoproteins and lipid compositions were essentially similar among all lipoproteins differing in monoacid species, except for apo A-IV. The Vmax of LPL for 16:0-rich chylomicrons and VLDLs were higher than for 18:1- or 18:2-rich lipoproteins. Order parameter (S), an indicator of the surface fluidity of lipoproteins, decreased with the chain length and unsaturation of monoacid in similar manner as the Vmax. The Vmax of LPL increased linearly (P < 0.05) with an increase in either the palmitic acid content of the lipoprotein triacylglycerols or order parameter (S) of the lipoproteins. The order parameter (S) and Vmax of LPL were higher in 16:0 triacylglycerol emulsions with apo B than with 18:1 or 18:2 triacylglycerols. The apo A-IV in triacylglycerol emulsions stimulated Vmax of LPLs in the presence of apo B and apo C-II. The binding of apo A-IV to 16:0 triacylglycerol emulsions was higher than to other triacylglycerol emulsions. These findings suggest that lipoprotein catalysis by LPL is modulated by the 16:0 level in the lipoprotein triacylglycerol, which affects the surface fluidity and apo A-IV content of lipoproteins.