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Total Entries: 10690
Title:
Organelle-specific death pathways
Authors:
Pun, K. T.; Brown, R. J.
Abstract:
Published:
2000
Title:
Oxidation of Linoleic Acid in Low-Density Lipoprotein: An Important Event in Atherogenesis
Authors:
Spiteller, D; Spiteller, G
Abstract:
Contrary to earlier views the main oxidation products of low-density lipoprotein (LDL) are derived from linoleic acid and not arachidonic acid, as determined by GC/MS investigations of the in vitro oxidation of LDL samples. A similar product spectrum, in which epoxyhydroxyoctadecenoic acids such as 1 and 2 have been identified for the first time, is obtained from minimally oxidized (that is, aged) LDL. Since this is still recognized by the LDL receptor, it is concluded that toxic oxidation products are introduced in endothelial cells in vivo and cause damage there.
Published:
2000
Title:
Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets
Authors:
Cordain, Loren; Miller, Janette Brand; Eaton, S. Boyd; Mann, Neil; Holt, Susanne H.A.; Speth, John D.
Abstract:
Both anthropologists and nutritionists have long recognized that the diets of modern-day hunter-gatherers may represent a reference standard for modern human nutrition and a model for defense against certain diseases of affluence. Because the hunter-gatherer way of life is now probably extinct in its purely un-Westernized form, nutritionists and anthropologists must rely on indirect procedures to reconstruct the traditional diet of preagricultural humans. In this analysis, we incorporate the most recent ethnographic compilation of plant-to-animal economic subsistence patterns of hunter-gatherers to estimate likely dietary macronutrient intakes (% of energy) for environmentally diverse hunter-gatherer populations. Furthermore, we show how differences in the percentage of body fat in prey animals would alter protein intakes in hunter-gatherers and how a maximal protein ceiling influences the selection of other macronutrients. Our analysis showed that whenever and wherever it was ecologically possible, hunter-gatherers consumed high amounts (45-65% of energy) of animal food. Most (73%) of the worldwide hunter-gatherer societies derived \textgreater50% (\textgreater or =56-65% of energy) of their subsistence from animal foods, whereas only 14% of these societies derived \textgreater50% (\textgreater or =56-65% of energy) of their subsistence from gathered plant foods. This high reliance on animal-based foods coupled with the relatively low carbohydrate content of wild plant foods produces universally characteristic macronutrient consumption ratios in which protein is elevated (19-35% of energy) at the expense of carbohydrates (22-40% of energy).
Published:
2000
Title:
Systematic review of epidemiological studies on meat, dairy products and egg consumption and risk of colorectal adenomas
Authors:
Yoon, H.; Benamouzig, R.; Little, J.; François-Collange, M.; Tomé, D.
Abstract:
In view of the direct contact between food residues and metabolites and the large bowel mucosa, it might be expected that food consumption patterns would affect the risk of colorectal carcinogenesis. Many lines of evidence support the adenoma-carcinoma sequence as the major mechanism of colorectal carcinogenesis. The present study aimed to investigate the role of foods of animal origin such as meat, dairy products and eggs in the early stages of colorectal carcinogenesis. Eleven case-control and two cohort studies on colorectal polyps and meat, dairy products and eggs were identified. A quantitative review of these studies and a meta-analysis were carried out. The combined odds ratios suggest a positive association between the risk of colorectal polyps and beef consumption and a negative association with fish or combined poultry/fish consumption. An increase in the ratio of the consumption of red meat to consumption of fish/chicken was associated with an increase in the colorectal polyp risk. Neither dairy product nor egg consumption had a substantial effect on the development of colorectal polyps. These results suggest that dietary factors associated with polyp development may be not the same as those associated with cancer. (C) 2000 Lippincott Williams and Wilkins.
Published:
2000
Title:
TNFα and the TNF receptor superfamily: Structure-function relationship(s)
Authors:
Idriss, Haitham T.; Naismith, James H.
Abstract:
Tumour Necrosis Factor α (TNFα), is an inflammatory cytokine produced by macrophages/monocytes during acute inflammation and is responsible for a diverse range of signalling events within cells, leading to necrosis or apoptosis. The protein is also important for resistance to infection and cancers. TNFα exerts many of its effects by binding, as a trimer, to either a 55 kDa cell membrane receptor termed TNFR-1 or a 75 kDa cell membrane receptor termed TNFR-2. Both these receptors belong to the so-called TNF receptor superfamily. The superfamily includes FAS, CD40, CD27, and RANK. The defining trait of these receptors is an extra cellular domain comprised of two to six repeats of cysteine rich motifs. Additionally, a number of structurally related “decoy receptors” exist that act to sequester TNF molecules, thereby rescuing cells from apoptosis. The crystal structures of TNFα, TNFβ, the extracellular domain of TNFR-1 (denoted sTNFR-1), and the TNFβ sTNFR-1 complex have been defined by crystallography. This article will review the structure/function relationships of the TNFα and the TNF receptor superfamily. It will also discuss insights as to how structural features play a role in the pleiotropic effects of TNFα. Microsc. Res. Tech. 50:184–195, 2000. © 2000 Wiley-Liss, Inc.
Published:
2000
Title:
Taxonomy of the Dmanisi crania
Authors:
Schwartz, J. H
Abstract:
Published:
2000
Title:
Temporal trends and metric variation in the mandibles and dentition of Australopithecus afarensis
Authors:
Lockwood, C. A; Kimbel, W. H; Johanson, D. C
Abstract:
Published:
2000
Title:
The Cholesterol Myths: Exposing the Fallacy That Saturated Fat and Cholesterol Cause Heart Disease
Authors:
Ravnskov, Uffe
Abstract:
Published:
2000
Title:
The Diverse Uses of Fish-Poison Plants in Northwest Guyana
Authors:
Andel, Tinde van
Abstract:
Although prohibited by law, fish poison plants are still widely used by indigenous tribes in Guyana. The latest ethnobotanical collections date from the first half of the 20th century and, from recent anthropological studies, it cannot be deduced whether the same species are still used today. The present study attempts to clarify the taxonomy and ethnobotany of the fish poisons, in particular those containing rotenone, currently used by Amerindians in northwest Guyana. Specimens were collected from 11 species known to be ichthyotoxic, both from wild and cultivated sources. It was found that fish poisons not only serve as a quick method of providing food in times of shortage, but also play an important role in magic rituals and traditional medicine. Particularly striking was the use of Lonchocarpus spp. and Tephrosia sinapou in the treatment of cancer and AIDS. Further ethnobotanical and pharmacological research should focus on the medicinal applications of rotenone-yielding plants. /// Aunque prohibidos por la ley, los barbascos aún son usados ampliamente por las tribus indígenas de Guyana. En dicha región, las colectas etnobotánicas más recientes datan de la primera mitad del siglo XX y desafortunadamente los estudios antropológicos contemporáneos no señalan los nombres científicos de las especies utilizadas. Este artículo tiene por objetivo aclarar la taxonomía y etnobotánica de los barbascos empleados actualmente por los amerindios del Noroeste de Guyana. Se colectaron muestras de once especies, cultivadas y silvestres, reconocidas como ictiotóxicas. Se encontró que los barbascos no solo proporcionan un método rápido para obtener alimento en tiempos de escasez, también son ingredientes importantes en rituales mágicos y como plantas medicinales. En particular es sorprendente el uso de Lonchocarpus spp. y Tephrosia sinapou en el tratamiento del cancer y SIDA. Las investigaciones etnobotánicas y farmacológicas futuras deben enfocarse a las aplicaciones médicas de las plantas que contienen rotenoides.
Published:
2000
Title:
The Effect of Inflammation and Infection on Lipids and Lipoproteins
Authors:
Feingold, Kenneth R.; Grunfeld, Carl
Abstract:
Chronic inflammatory diseases, such as rheumatoid arthritis, systemic lupus erythematosus, and psoriasis and infections, such as periodontal disease and HIV, are associated with an increased risk of cardiovascular disease. Patients with these disorders also have an increase in coronary artery calcium measured by CT and carotid intima media thickness measured by ultrasound. Inflammation and infections induce a variety of alterations in lipid metabolism that may initially dampen inflammation or fight infection, but if chronic could contribute to the increased risk of atherosclerosis. The most common changes are decreases in serum HDL and increases in triglycerides. The increase in serum triglycerides is due to both an increase in hepatic VLDL production and secretion and a decrease in the clearance of triglyceride rich lipoproteins. The mechanisms by which inflammation and infection decrease HDL levels are uncertain. There is also a consistent increase in lipoprotein (a) levels due to increased apolipoprotein (a) synthesis. LDL levels are frequently decreased but the prevalence of small dense LDL is increased due to cholesterol ester transfer protein (CETP) mediated exchange of triglycerides from triglyceride rich lipoproteins to LDL followed by triglyceride hydrolysis. In addition to affecting serum lipid levels, inflammation also adversely effects lipoprotein function. LDL is more easily oxidized as the ability of HDL to prevent the oxidation of LDL is diminished. Moreover, there are a number of steps in the reverse cholesterol transport pathway that are adversely affected during inflammation. The greater the severity of the underlying inflammatory disease, the more consistently these abnormalities in lipids and lipoproteins are observed. Treatment of the underlying disease leading to a reduction in inflammation results in the return of the lipid profile towards normal. The changes in lipids and lipoproteins that occur during inflammation and infection are part of the innate immune response and therefore are likely to play an important role in protecting the host. The guidelines for the management of lipid disorders and the standard risk calculators for predicting cardiovascular disease (ACC/AHA, Framingham, etc.) underestimate the risk in patients with inflammation. It has been recommended to increase the calculated risk by approximately 50% in patients with severe inflammatory disorders. The treatment of lipid disorders in patients with inflammatory disorders is similar to patients without inflammatory disorders. Of note statins, fibrates, and fish oil have anti-inflammatory properties and have been reported to have beneficial effects on many of these inflammatory disorders.
Published:
2000
Title:
The Myc/Max/Mad Network and the Transcriptional Control of Cell Behavior
Authors:
Grandori, Carla; Cowley, Shaun M.; James, Leonard P.; Eisenman, Robert N.
Abstract:
The Myc/Max/Mad network comprises a group of transcription factors whose distinct interactions result in gene-specific transcriptional activation or repression. A great deal of research indicates that the functions of the network play roles in cell proliferation, differentiation, and death. In this review we focus on the Myc and Mad protein families and attempt to relate their biological functions to their transcriptional activities and gene targets. Both Myc and Mad, as well as the more recently described Mnt and Mga proteins, form heterodimers with Max, permitting binding to specific DNA sequences. These DNA-bound heterodimers recruit coactivator or corepressor complexes that generate alterations in chromatin structure, which in turn modulate transcription. Initial identification of target genes suggests that the network regulates genes involved in the cell cycle, growth, life span, and morphology. Because Myc and Mad proteins are expressed in response to diverse signaling pathways, the network can be viewed as a functional module which acts to convert environmental signals into specific gene-regulatory programs.
Published:
2000
Title:
Vegan diet alleviates fibromyalgia symptoms
Authors:
Kaartinen, K.; Lammi, K.; Hypen, M.; Nenonen, M.; Hanninen, O.; Rauma, A. L.
Abstract:
The effect of a strict, low-salt, uncooked vegan diet rich in lactobacteria on symptoms in 18 fibromyalgia patients during and after a 3-month intervention period in an open, non-randomized controlled study was evaluated. As control 15 patients continued their omnivorous diet. The groups did not differ significantly from each other in the beginning of the study in any other parameters except in pain and urine sodium. The results revealed significant improvements in Visual analogue scale of pain (VAS) (p=0.005), joint stiffness (p=0.001), quality of sleep (p=0.0001), Health assessment questionnaire (HAQ) (p=0.031), General health questionnaire (GHQ) (p=0.021), and a rheumatologist's own questionnaire (p=0.038). The majority of patients were overweight to some extent at the beginning of the study and shifting to a vegan food caused a significant reduction in body mass index (BMI) (p=0.0001). Total serum cholesterol showed a statistically significant lowering (p=0.003). Urine sodium dropped to 1/3 of the beginning values (p=0.0001) indicating good diet compliance. It can be concluded that vegan diet had beneficial effects on fibromyalgia symptoms at least in the short run.
Published:
2000
Title:
Wild Plants in the Diet of Arhorchin Mongol Herdsmen in Inner Mongolia
Authors:
Khasbagan; Huai, Hu-Yin; Pei, Sheng-Ji
Abstract:
Arhorchin Mongol herdsmen are one of the tribal and regional groups of the Mongol nationality still engaged in traditional animal husbandry in the grassland areas of eastern Inner Mongolia at present. There are 77 species of wild plants used in their diet. An ethnobotanical inventory is presented, which includes the botanical names, folk names, parts used, usage, and the numbers of voucher specimens. Distinctive national features of the use of wild plants in their diet are expressed in the aspects that the Arhorchin Mongol herdsmen integrate to wild plants with their traditional diet and bromatherapy. Traditional usage may be used to exploit patterns of wild food plants in grassland areas.
Published:
2000
Title:
[Blood lipids and intensity of free radical oxidant processes in elderly patients with ischemic heart disease on antiatherogenic vegetarian diet]
Authors:
Medkova, I. L.; Ivanov, A. N.; Mosiakina, L. I.; Goncharov, L. F.
Abstract:
The authors studied the effects of balanced antiatherogenic vegetarian diet enriched with soya bean products on blood lipids and intensity of free radical oxidant processes in elderly patients with ischemic heart disease. 45 patients with dyslipoproteinemia type IIA or IIB were examined for hemodynamic parameters, lipid spectrum and intensity of free radical oxidation. The diet promoted a trend to normalization of central hemodynamics, significantly reduced the level of atherogenic lipids in blood, improved free radical lipid peroxidation and activity of nonenzymatic antioxidant defence.
Published:
2000
Title:
[Nutritional risk factors of a vegetarian diet in adult lacto-ovo vegetarians]
Authors:
Krajcovicova-Kudlackova, M.; Simoncic, R.; Bederova, A.; Klvanova, J.; Magalova, T.; Grancicova, E.; Brtkova, A.
Abstract:
Risk nutritional factors of alternative alimentation detected in childhood were evaluated in a group of adult lactoovovegetarians (n = 47). The levels of iron, calcium, zinc, total proteins, gluthatione, plasmatic profile of fatty acids and the lipoperoxidation product in correlation with the values of antioxidative vitamins were studied. The results are compared with mean sample upon mixed nutrition (omnivores n = 42). In both groups were the mean values of iron, calcium and zinc in physiological range, but significantly lower in vegetarians. In the alternative nutrition group was in 21 percent of probands hyposiderinemia detected (vs 5 percent in the omnivores group), in 19 percent of probands hypocalcemia (vs 9 percent) and in 6 percent hypozincemia (vs 0 percent). Full-bodied mixture of milk proteins, egg proteins and vegetable sources in lactoovovegetarians ensured sufficient protein saturation and caused significantly higher level of blood gluthatione (intake also in food). Increased value of fatty acid peroxidation index was not due to increased lipoperoxidation in lactoovovegetarians--significantly lower levels of conjugated fatty acid dienes were determined. This was ensured by sufficient protection by means of essential antioxidants--the levels of vitamins E, C, beta-carotene are in vegetarians significantly higher. These are overtreshold values representing reduced risk of free-radical diseases. Lactoovovegetarians had significantly higher content of linoleic and alpha-linoleic acids in plasma. Values of polyunsaturated fatty acids with C20 and C22 and 3-6 double bonds were similar to values in omnivores. In probands on alternative nutrition with iron deficit was significantly lower activity of delta 6 desaturase determined. (Tab. 3, Ref. 45.)
Published:
2000
Title:
β-Carotene and Other Carotenoids
Authors:
Compounds, Institute of Medicine (US) Panel on Dietary Antioxidants and Related
Abstract:
Blood concentrations of carotenoids are the best biological markers for consumption of fruits and vegetables. A large body of observational epidemiological evidence suggests that higher blood concentrations of β-carotene and other carotenoids obtained from foods are associated with lower risk of several chronic diseases. This evidence, although consistent, cannot be used to establish a requirement for β-carotene or carotenoid intake because the observed effects may be due to other substances found in carotenoidrich food, or to other behavioral correlates of increased fruit and vegetable consumption. While there is evidence that β-carotene is an antioxidant in vitro, its importance to health is not known. The one clear function of certain carotenoids that is firmly linked to a health outcome is the provitamin A activity of some dietary carotenoids (α-carotene, β-carotene, and β-cryptoxanthin) and their role in the prevention of vitamin A deficiency. Establishment of a requirement for carotenoids based upon vitamin A activity must be done in concert with the evaluation of Dietary Reference In-takes (DRIs) for vitamin A, which was not included in this report, but will be addressed in a subsequent DRI report. Although no DRIs are proposed for β-carotene or other carotenoids at the present time, existing recommendations for increased consumption of carotenoid-rich fruits and vegetables are supported. Based on evidence that β-carotene supplements have not been shown to confer any benefit for the prevention of the major chronic diseases and may cause harm in certain subgroups, it is concluded that β-carotene supplements are not advisable, other than as a provitamin A source and for the prevention and control of vitamin A deficiency in at-risk populations.
Published:
2000
Title:
Animal models of the ketogenic diet: what have we learned, what can we learn?
Authors:
Stafstrom, C. E.
Abstract:
Despite its clinical use as a therapy for refractory epilepsy for more than 75 years, the ketogenic diet (KD) remains a therapy in search of an explanation. The mechanism of action of the KD is unclear and the optimal indications for its clinical use are incompletely defined. Animal models could help to elucidate these questions. Surprisingly, there have been very few animal studies of the KD, and those that have been performed are difficult to compare because of wide discrepancies in experimental methods. Earlier models concentrated on the effect of the KD on acute seizure threshold in normal (i.e. nonepileptic) animals. Recent studies are beginning to examine the longer term effects of the KD and its role in epileptogenesis. Some features of clinical experience have been replicated in animal models, including the role of ketosis, elevation of seizure threshold by both classic ketogenic and medium chain triglyceride diets, better effectiveness at younger ages, and rapid reversal of the seizure protective effect when the diet is discontinued. These parallels raise hope that pertinent clinical questions can be addressed in the more controlled setting of the research laboratory. As in the clinical arena, there has been a recent resurgence of interest in pursuing basic questions related to the ketogenic diet, using techniques of modern neuroscience. Experimental approaches such as brain slice neurophysiology, genetic models, dissection of metabolic pathways, and neurohistological techniques hold much promise in the effort to understand this intriguing alternative to standard anticonvulsants.
Published:
1999-12
Title:
Metabolic adaptations to a high-fat diet in endurance cyclists
Authors:
Goedecke, J. H.; Christie, C.; Wilson, G.; Dennis, S. C.; Noakes, T. D.; Hopkins, W. G.; Lambert, E. V.
Abstract:
We examined the time course of metabolic adaptations to 15 days of a high-fat diet (HFD). Sixteen endurance-trained cyclists were assigned randomly to a control (CON) group, who consumed their habitual diet (30% +/- 8% mJ fat), or a HFD group, who consumed a high-fat isocaloric diet (69% +/- 1% mJ fat). At 5-day intervals, the subjects underwent an oral glucose tolerance test (OGTT); on the next day, they performed a 2.5-hour constant-load ride at 70% peak oxygen consumption (VO2peak), followed by a simulated 40-km cycling time-trial while ingesting a 10% 14C-glucose + 3.44% medium-chain triglyceride (MCT) emulsion at a rate of 600 mL/h. In the OGTT, plasma glucose concentrations at 30 minutes increased significantly after 5 days of the HFD and remained elevated at days 10 and 15 versus the levels measured prior to the HFD (P < .05). The activity of carnitine acyltransferase (CAT) in biopsies of the vastus lateralis muscle also increased from 0.45 to 0.54 micromol/g/min over days 0 to 10 of the HFD (P < .01) without any change in citrate synthase (CS) or 3-hydroxyacyl-coenzyme A dehydrogenase (3-HAD) activities. Changes in glucose tolerance and CAT activity were associated with a shift from carbohydrate (CHO) to fat oxidation during exercise (P < .001), which occurred within 5 to 10 days of the HFD. During the constant-load ride, the calculated oxidation of muscle glycogen was reduced from 1.5 to 1.0 g/min (P
Published:
1999-12
Title:
On Diet and Gut Size in Non-human Primates and Humans: Is There a Relationship to Brain Size?
Authors:
Hladik, null; Chivers, null; Pasquet, null
Abstract:
Published:
1999-12
Title:
Some dietary fibers reduce the absorption of carotenoids in women
Authors:
Riedl, J.; Linseisen, J.; Hoffmann, J.; Wolfram, G.
Abstract:
Dietary fiber may be partly responsible for the lower bioavailability of carotenoids from food than from purified supplements. Due to the lack of detailed information available, we investigated the effects of different kinds of dietary fiber on the absorption of carotenoids and alpha-tocopherol. Six healthy young women received an antioxidant mixture consisting of beta-carotene, lycopene, lutein, canthaxanthin and alpha-tocopherol together with a standard meal. The meal did not contain additional dietary fiber or was enriched with pectin, guar, alginate, cellulose or wheat bran (0. 15 g. kg body weight(-1)). The increases in plasma carotenoid and alpha-tocopherol concentrations were followed over 24 h, and the areas-under-curves (AUC(24h)) were calculated. The mean AUC(24h) of beta-carotene was significantly (P < 0.05) reduced by the water-soluble fibers pectin, guar and alginate with a mean decrease of 33-43%. All tested fibers significantly reduced the AUC(24h) of lycopene and lutein by 40-74% (P
Published:
1999-12
Title:
Vegan proteins may reduce risk of cancer, obesity, and cardiovascular disease by promoting increased glucagon activity
Authors:
McCarty, M. F.
Abstract:
Amino acids modulate the secretion of both insulin and glucagon; the composition of dietary protein therefore has the potential to influence the balance of glucagon and insulin activity. Soy protein, as well as many other vegan proteins, are higher in non-essential amino acids than most animal-derived food proteins, and as a result should preferentially favor glucagon production. Acting on hepatocytes, glucagon promotes (and insulin inhibits) cAMP-dependent mechanisms that down-regulate lipogenic enzymes and cholesterol synthesis, while up-regulating hepatic LDL receptors and production of the IGF-I antagonist IGFBP-1. The insulin-sensitizing properties of many vegan diets--high in fiber, low in saturated fat--should amplify these effects by down-regulating insulin secretion. Additionally, the relatively low essential amino acid content of some vegan diets may decrease hepatic IGF-I synthesis. Thus, diets featuring vegan proteins can be expected to lower elevated serum lipid levels, promote weight loss, and decrease circulating IGF-I activity. The latter effect should impede cancer induction (as is seen in animal studies with soy protein), lessen neutrophil-mediated inflammatory damage, and slow growth and maturation in children. In fact, vegans tend to have low serum lipids, lean physiques, shorter stature, later puberty, and decreased risk for certain prominent 'Western' cancers; a vegan diet has documented clinical efficacy in rheumatoid arthritis. Low-fat vegan diets may be especially protective in regard to cancers linked to insulin resistance--namely, breast and colon cancer--as well as prostate cancer; conversely, the high IGF-I activity associated with heavy ingestion of animal products may be largely responsible for the epidemic of 'Western' cancers in wealthy societies. Increased phytochemical intake is also likely to contribute to the reduction of cancer risk in vegans. Regression of coronary stenoses has been documented during low-fat vegan diets coupled with exercise training; such regimens also tend to markedly improve diabetic control and lower elevated blood pressure. Risk of many other degenerative disorders may be decreased in vegans, although reduced growth factor activity may be responsible for an increased risk of hemorrhagic stroke. By altering the glucagon/insulin balance, it is conceivable that supplemental intakes of key non-essential amino acids could enable omnivores to enjoy some of the health advantages of a vegan diet. An unnecessarily high intake of essential amino acids--either in the absolute sense or relative to total dietary protein--may prove to be as grave a risk factor for 'Western' degenerative diseases as is excessive fat intake.
Published:
1999-12
Title:
Changes in renal function during weight loss induced by high vs low-protein low-fat diets in overweight subjects
Authors:
Skov, A. R.; Toubro, S.; Bülow, J.; Krabbe, K.; Parving, H. H.; Astrup, A.
Abstract:
BACKGROUND: Due to the high satiating effect of protein, a high-protein diet may be desirable in the treatment of obesity. However the long-term effect of different levels of protein intake on renal function is unclear. OBJECTIVE: To assess the renal effects of high vs low protein contents in fat-reduced diets. DESIGN: Randomized 6 months dietary intervention study comparing two controlled ad libitum diets with 30 energy (E%) fat content: high-protein (HP; 25 E%) or low-protein, (LP, 12 E% protein). All food was provided by self-selection in a shop at the department, and high compliance to the diet composition was confirmed by measurements of urinary nitrogen excretion. SUBJECTS: 65 healthy, overweight and obese (25<body mass index (BMI)<34 kg/m2). RESULTS: Dietary protein intake changed from 91.1 g/d to a 6 months intervention average of 70.4 g/d (P<0.05) in the LP group and from 91.4 g/d to 107.8 g/d (P<0.05) in the HP group, producing changes in glomerular filtration rate (GFR) of -7.1 ml/min in the LP group and +5. 2 ml/min in the HP group (group effect: P<0.05). Kidney volume decreased by -6.2 cm3 in the LP group and increased by +9.1 cm3 in the HP group (P
Published:
1999-11
Title:
Comparative biotransformation studies of MeIQx and PhIP in animal models and humans
Authors:
Garner, R. C.; Lightfoot, T. J.; Cupid, B. C.; Russell, D.; Coxhead, J. M.; Kutschera, W.; Priller, A.; Rom, W.; Steier, P.; Alexander, D. J.; Leveson, S. H.; Dingley, K. H.; Mauthe, R. J.; Turteltaub, K. W.
Abstract:
MeIQx and PhIP are putative carcinogenic heterocyclic amines formed during the cooking of meat and fish. Using accelerator mass spectrometry, we have investigated the metabolism and macromolecule binding of 14C-labelled MeIQx and PhIP in human cancer patients compared to the rat. Following oral administration of MeIQx and PhIP, more DNA adducts were formed in human colon tissue compared with rats. Differences were also observed between rats and humans in the metabolite profile and urine excretion for these compounds. These results suggest humans metabolise heterocyclic amines differently to laboratory rodents and question their use as models of human risk.
Published:
1999-09
Title:
Dietary intake and iron status of Australian vegetarian women
Authors:
Ball, M. J.; Bartlett, M. A.
Abstract:
BACKGROUND: Despite the possible overall health benefits of a vegetarian diet, there is concern that some vegetarians and infrequent meat eaters, particularly females, may have inadequate iron status because of low or no heme-iron intakes. OBJECTIVE: The objective was to investigate the nutritional intake and iron status of vegetarian women. DESIGN: The nutritional intakes of 50 free-living vegetarian women aged 18-45 y and 24 age-matched omnivorous control women were assessed by using 12-d weighed dietary records. Iron status was assessed by measuring hemoglobin and serum ferritin concentrations. RESULTS: There was no significant difference between mean (+/-SD) daily iron intakes of vegetarians and omnivores (10.7 +/- 4.4 and 9.9 +/- 2.9 mg, respectively), although heme-iron intakes were low in the vegetarians. Vegetarians had significantly lower intakes of protein (P < 0.01), saturated fat (P < 0.01), and cholesterol (P < 0.001), and significantly higher intakes of dietary fiber (P < 0.001) and vitamin C (P < 0.05). Mean serum ferritin concentrations were significantly lower (P = 0.025) in vegetarians (25.0 +/- 16.2 microg/L) than in omnivores (45.5 +/- 42.5 microg/L). However, similar numbers of vegetarians (18%) and omnivores (13%) had serum ferritin concentrations
Published:
1999-09
Title:
Differential binding of triglyceride-rich lipoproteins to lipoprotein lipase
Authors:
Xiang, S. Q.; Cianflone, K.; Kalant, D.; Sniderman, A. D.
Abstract:
In comparison to very low density lipoprotein (VLDL), chylomicrons are cleared quickly from plasma. However, small changes in fasting plasma VLDL concentration substantially delay postprandial chylomicron triglyceride clearance. We hypothesized that differential binding to lipoprotein lipase (LPL), the first step in the lipolytic pathway, might explain these otherwise paradoxical relationships. Competition binding assays of different lipoproteins were performed in a solid phase assay with purified bovine LPL at 4 degrees C. The results showed that chylomicrons, VLDL, and low density lipoprotein (LDL) were able to inhibit specific binding of (125)I-labeled VLDL to the same extent (85.1% +/- 13.1, 100% +/- 6.8, 90.7% +/- 23.2% inhibition, P = NS), but with markedly different efficiencies. The rank order of inhibition (K(i)) was chylomicrons (0.27 +/- 0.02 nm apoB) > VLDL (12.6 +/- 3.11 nm apoB) > LDL (34.8 +/- 11.1 nm apoB). By contrast, neither triglyceride (TG) liposomes, high density lipoprotein (HDL), nor LDL from patients with familial hypercholesterolemia were efficient at displacing the specific binding of (125)I-labeled VLDL to LPL (30%, 39%, and no displacement, respectively). Importantly, smaller hydrolyzed chylomicrons had less affinity than the larger chylomicrons (K(i) = 2.34 +/- 0.85 nm vs. 0.27 +/- 0.02 nm apoB respectively, P
Published:
1999-09
Title:
Vegetarian diet: panacea for modern lifestyle diseases?
Authors:
Segasothy, M.; Phillips, P. A.
Abstract:
We review the beneficial and adverse effects of vegetarian diets in various medical conditions. Soybean-protein diet, legumes, nuts and soluble fibre significantly decrease total cholesterol, low-density lipoprotein cholesterol and triglycerides. Diets rich in fibre and complex carbohydrate, and restricted in fat, improve control of blood glucose concentration, lower insulin requirement and aid in weight control in diabetic patients. An inverse association has been reported between nut, fruit, vegetable and fibre consumption, and the risk of coronary heart disease. Patients eating a vegetarian diet, with comprehensive lifestyle changes, have had reduced frequency, duration and severity of angina as well as regression of coronary atherosclerosis and improved coronary perfusion. An inverse association between fruit and vegetable consumption and stroke has been suggested. Consumption of fruits and vegetables, especially spinach and collard green, was associated with a lower risk of age-related ocular macular degeneration. There is an inverse association between dietary fibre intake and incidence of colon and breast cancer as well as prevalence of colonic diverticula and gallstones. A decreased breast cancer risk has been associated with high intake of soy bean products. The beneficial effects could be due to the diet (monounsaturated and polyunsaturated fatty acids, minerals, fibre, complex carbohydrate, antioxidant vitamins, flavanoids, folic acid and phytoestrogens) as well as the associated healthy lifestyle in vegetarians. There are few adverse effects, mainly increased intestinal gas production and a small risk of vitamin B12 deficiency.
Published:
1999-09
Title:
Dietary analysis in symptomatic patients with coeliac disease on a gluten-free diet: the role of trace amounts of gluten and non-gluten food intolerances
Authors:
Faulkner-Hogg, K. B.; Selby, W. S.; Loblay, R. H.
Abstract:
BACKGROUND: Whereas many people with coeliac disease (CD) are asymptomatic when consuming a gluten-free diet (GFD), a proportion continues to experience symptoms. The reasons for this are unclear. METHODS: Thirty-nine adult members of The Coeliac Society of New South Wales, all of whom had persistent gastrointestinal symptoms despite adhering to a GFD, were evaluated. Dietary analysis indicated that 22 (56%) were consuming a GFD as defined by the WHO/FAO Codex Alimentarius (Codex-GFD), in which foods containing up to 0.3% of protein from gluten-containing grains can be labelled as 'gluten free'. The remaining 17 were following a no detectable gluten diet (NDG)-GFD, as defined by Food Standards Australia. All subjects were required to follow a NDG-GFD during the study. Those in whom symptoms persisted after changing from a Codex-GFD and those who entered the study already on a NDG-GFD began an elimination diet followed by open and double-blind challenges to identify specific non-gluten food or food chemical intolerances. RESULTS: Of 22 patients who switched to a NDG-GFD symptoms resolved in 5 (23%) and were reduced in 10 others (45%). Thirty-one subjects commenced the elimination diet. Symptomatic improvement was experienced in 24 (77%). Subsequent food or food chemical challenges resulted in a mean of five positive challenges per individual. Diarrhoea was the most commonly provoked symptom, followed by headache, nausea, and flatulence. Symptoms were especially provoked by amine, salicylate and soy. CONCLUSION: The consumption of trace amounts of gluten, traditionally allowed in a Codex-GFD, may be responsible for the continuing symptoms seen in some patients with CD. Further investigation for non-gluten food intolerances should follow if symptoms persist after adherence to a NDG-GFD.
Published:
1999-08
Title:
Toward improved management of NIDDM: A randomized, controlled, pilot intervention using a lowfat, vegetarian diet
Authors:
Nicholson, A. S.; Sklar, M.; Barnard, N. D.; Gore, S.; Sullivan, R.; Browning, S.
Abstract:
OBJECTIVE: To investigate whether glycemic and lipid control in patients with non-insulin-dependent diabetes (NIDDM) can be significantly improved using a low-fat, vegetarian (vegan) diet in the absence of recommendations regarding exercise or other lifestyle changes. METHODS: Eleven subjects with NIDDM recruited from the Georgetown University Medical Center or the local community were randomly assigned to a low-fat vegan diet (seven subjects) or a conventional low-fat diet (four subjects). Two additional subjects assigned to the control group failed to complete the study. The diets were not designed to be isocaloric. Fasting serum glucose, body weight, medication use, and blood pressure were assessed at baseline and biweekly thereafter for 12 weeks. Serum lipids, glycosylated hemoglobin, urinary albumin, and dietary macronutrients were assessed at baseline and 12 weeks. RESULTS: Although the sample was intentionally small in accordance with the pilot study design, the 28% mean reduction in fasting serum glucose of the experimental group, from 10.7 to 7.75 mmol/L (195 to 141 mg/dl), was significantly greater than the 12% decrease, from 9.86 to 8.64 mmol/L (179 to 157 mg/dl), for the control group (P < 0.05). The mean weight loss was 7.2 kg in the experimental group, compared to 3. 8 kg for the control group (P < 0.005). Of six experimental group subjects on oral hypoglycemic agents, medication use was discontinued in one and reduced in three. Insulin was reduced in both experimental group patients on insulin. No patient in the control group reduced medication use. Differences between the diet groups in the reductions of serum cholesterol and 24-h microalbuminuria did not reach statistical significance; however, high-density lipoprotein concentration fell more sharply (0.20 mmol/L) in the experimental group than in the control group (0.02 mmol/L) (P
Published:
1999-08
Title:
Muscle net glucose uptake and glucose kinetics after endurance training in men
Authors:
Bergman, B. C.; Butterfield, G. E.; Wolfel, E. E.; Lopaschuk, G. D.; Casazza, G. A.; Horning, M. A.; Brooks, G. A.
Abstract:
We evaluated the hypotheses that alterations in glucose disposal rate (R(d)) due to endurance training are the result of changed net glucose uptake by active muscle and that blood glucose is shunted to working muscle during exercise requiring high relative power output. We studied leg net glucose uptake during 1 h of cycle ergometry at two intensities before training [45 and 65% of peak rate of oxygen consumption (VO(2 peak))] and after training [65% pretraining VO(2 peak), same absolute workload (ABT), and 65% posttraining VO(2 peak), same relative workload (RLT)]. Nine male subjects (178.1 +/- 2.5 cm, 81.8 +/- 3.3 kg, 27.4 +/- 2.0 yr) were tested before and after 9 wk of cycle ergometer training, five times a week at 75% VO(2 peak). The power output that elicited 66.0 +/- 1.1% of VO(2 peak) before training elicited 54.0 +/- 1.7% after training. Whole body glucose R(d) decreased posttraining at ABT (5.45 +/- 0.31 mg. kg(-1). min(-1) at 65% pretraining to 4.36 +/- 0.44 mg. kg(-1). min(-1)) but not at RLT (5.94 +/- 0.47 mg. kg(-1). min(-1)). Net glucose uptake was attenuated posttraining at ABT (1.87 +/- 0.42 mmol/min at 65% pretraining and 0.54 +/- 0.33 mmol/min) but not at RLT (2.25 +/- 0. 81 mmol/min). The decrease in leg net glucose uptake at ABT was of similar magnitude as the drop in glucose R(d) and thus could explain dampened glucose flux after training. Glycogen degradation also decreased posttraining at ABT but not RLT. Leg net glucose uptake accounted for 61% of blood glucose flux before training and 81% after training at the same relative (65% VO(2 peak)) workload and only 38% after training at ABT. We conclude that 1) alterations in active muscle glucose uptake with training determine changes in whole body glucose kinetics; 2) muscle glucose uptake decreases for a given, moderate intensity task after training; and 3) hard exercise (65% VO(2 peak)) promotes a glucose shunt from inactive tissues to active muscle.
Published:
1999-07
Title:
Bone's early responses to mechanical loading differ in distinct genetic strains of chick: selection for enhanced growth reduces skeletal adaptability
Authors:
Pitsillides, A. A.; Rawlinson, S. C.; Mosley, J. R.; Lanyon, L. E.
Abstract:
Bone's functional competence is established and maintained, at least partly, by mechanisms involving appropriate adaptation to mechanical loading. These appear to fail in chickens selectively bred either for maximum egg (Egg-type) or meat (Meat-type) production, which show high rates of fracture and skeletal abnormality, respectively. By measuring several early strain-induced responses in cultured embryonic tibiotarsi from commercially bred (Egg-type and Meat-type) and wild-type (Wild-type) chicks, we have investigated the possibility that these skeletal failures are the product of a compromised ability to respond appropriately to loading-induced mechanical strain. Axial loads engendering peak dynamic (1 Hz) longitudinal strains of between -1300 microepsilon and -1500 microepsilon (for 10 minutes) in vitro in tibiotarsi from the three types of 18-day-old chicks increased periosteal osteoblast glucose 6-phosphate dehydrogenase (G6PD) activity in both Wild-type (26%, p < 0.01) and Egg-type (49%, p < 0.001) chicks in situ, while Meat-type chicks did not show any significant changes (11%). Load-induced increases in medium nitrite accumulation (stable nitric oxide [NO] metabolite) were produced in Egg-type and Wild-type tibiotarsi (82 +/- 12%, p < 0.01; 39 +/- 8%, p < 0.01), respectively. In contrast, loading produced no change in NO release from Meat-type chick tibiotarsi. These changes in NO release correlated with load-related increases in G6PD activity (R2 = 0.98, p
Published:
1999-06
Title:
Gene shifting: A novel therapy for mitochondrial myopathy
Authors:
Taivassalo, Tanja; Fu, Katherine; Johns, Timothy; Arnold, Douglas; Karpati, George; Shoubridge, Eric A.
Abstract:
Mutations in mitochondrial DNA (mtDNA) are the most frequent causes of mitochondrial myopathy in adults. In the majority of cases mutant and wild-type mtDNAs coexist, a condition referred to as mtDNA heteroplasmy; however, the relative frequency of each species varies widely in different cells and tissues. Nearly complete segregation of mutant and wild-type mtDNAs has been observed in the skeletal muscle of many patients. In such patients mutant mtDNAs predominate in mature myofibers but are rare or undetectable in skeletal muscle satellite cells cultured in vitro. This pattern is thought to result from positive selection for the mutant mtDNA in post-mitotic myofibers and loss of the mutant by genetic drift in satellite cells. Satellite cells are dormant myoblasts that can be stimulated to re-enter the cell cycle and fuse with existing myofibers in response to signals for muscle growth or repair. We tested whether we could normalize the mtDNA genotype in mature myofibers in a patient with mitochondrial myopathy by enhancing the incorporation of satellite cells through regeneration following injury or muscle hypertrophy, induced by either eccentric or concentric resistance exercise training. We show a remarkable increase in the ratio of wild-type to mutant mtDNAs, in the proportion of muscle fibers with normal respiratory chain activity and in muscle fiber cross-sectional area after a short period of concentric exercise training. These data show that it is possible to reverse the molecular events that led to expression of metabolic myopathy and demonstrate the effectiveness of this form of 'gene shifting' therapy.
Published:
1999-06
Title:
Nutritional characteristics of wild primate foods: do the diets of our closest living relatives have lessons for us?
Authors:
Milton, K.
Abstract:
The widespread prevalence of diet-related health problems, particularly in highly industrialized nations, suggests that many humans are not eating in a manner compatible with their biology. Anthropoids, including all great apes, take most of their diet from plants, and there is general consensus that humans come from a strongly herbivorous ancestry. Though gut proportions differ, overall gut anatomy and the pattern of digestive kinetics of extant apes and humans are very similar. Analysis of tropical forest leaves and fruits routinely consumed by wild primates shows that many of these foods are good sources of hexoses, cellulose, hemicellulose, pectic substances, vitamin C, minerals, essential fatty acids, and protein. In general, relative to body weight, the average wild monkey or ape appears to take in far higher levels of many essential nutrients each day than the average American and such nutrients (as well as other substances) are being consumed together in their natural chemical matrix. The recommendation that Americans consume more fresh fruits and vegetables in greater variety appears well supported by data on the diets of free-ranging monkeys and apes. Such data also suggest that greater attention to features of the diet and digestive physiology of non-human primates could direct attention to important areas for future research on features of human diet and health.
Published:
1999-06
Title:
Vegetarian diet planning for adolescents with diabetes
Authors:
Rudkin, C. L.
Abstract:
Adolescents with insulin dependent diabetes mellitus (IDDM) who choose to be vegetarian have complex nutritional needs because of their continued physical growth and development, their participation in strenuous activities, and their need to consume sufficient carbohydrates to match their insulin doses. Since diet control is a cornerstone of diabetes management, the adolescent who chooses a vegetarian diet may cause their parents needless anxiety. Nurses working with these adolescents can provide support and guidance and liaison with the endocrinologist, nutritionist or dietitian, and diabetic educator. Although adolescent diabetic vegetarians have not been studied extensively as a population, facts about nutrition and diabetes can be used to assist in meal planning. A complete growth and nutritional assessment must be done to search for any problem areas. If protein dense flesh food is eliminated and a largely carbohydrate diet is consumed, there are additional areas of concern in regulating insulin needs. Blood glucose should be monitored very carefully during diet changes. Vegetarian girls with diabetes also should be carefully monitored for the adequacy of their diet because they may be at risk of developing an eating disorder.
Published:
1999-06
Title:
[Effects of a low calorie vegan diet on disease activity and general conditions in patients with rheumatoid arthritis]
Authors:
Fujita, A.; Hashimoto, Y.; Nakahara, K.; Tanaka, T.; Okuda, T.; Koda, M.
Abstract:
There is little objective information about diet therapy for rheumatoid arthritis (RA) in Japan. We studied 14 patients with RA who stayed in the Koda hospital for 55 days. They basically took a 1200 kcal vegan diet consisting of unpolished rice gruel, juice of raw vegetables, soya bean curd and sesame seeds, and undertook a 3-5-day fast three times. During the 55-day stay, average body weight decreased by 5.1kg. Lansbury index and ESR decreased whereas CRP did not change. WBC decreased and the differential cell counts showed a decrease of neutrophils, eosinophils and monocytes without a change in lymphocytes or basophils. RBC, hemoglobin and MCV increased. LDL-C decreased, while HDL-C increased. There was no change in total protein or albumin. These data suggest that this combination of a low calorie vegan diet and fasting may contribute to improve RA with little undesirable effects on the patient's general conditions.
Published:
1999-06
Title:
Diabetic cardiomyopathy and carnitine deficiency
Authors:
Malone, J. I.; Schocken, D. D.; Morrison, A. D.; Gilbert-Barness, E.
Abstract:
This study was designed to study the pathogenesis of cardiomyopathy in animals with longstanding (6 months) diabetes mellitus. Male Wistar rats were made diabetic by the injection of streptozotocin (35 mg/kg) intraperitoneal at 6 months of age. Myocardial contractility was evaluated at 1 year of age by an echocardiogram. Blood was collected at that time to measure blood glucose and hemoglobin A1c as an indicator of metabolic control. Serum carnitine was also measured on the same sample to evaluate the availability of this substance so essential for fatty acid metabolism in the myocardium. Myocardial anatomy was evaluated by both light and electron microscopy after the animals had diabetes for 6 months. It was found that the left ventricular volume was greater at the end of systole and diastole. There was the suggestion of left ventricular fractional shortening and calculated reduced ejection fraction indicating decreased contractility consistent with cardiomyopathy. The hearts had no evidence of coronary vascular occlusion, and the serum cholesterol was normal. Myocardial ultrastructure revealed abnormal-appearing mitochondria consistent with carnitine deficiency. Serum and myocardial carnitine levels in the animals with diabetes and reduced myocardial function were low. Carnitine levels and metabolism could be important in the pathogenesis of diabetic cardiomyopathy.
Published:
1999-04
Title:
The identification of [2-(14)C]2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine metabolites in humans
Authors:
Malfatti, M. A.; Kulp, K. S.; Knize, M. G.; Davis, C.; Massengill, J. P.; Williams, S.; Nowell, S.; MacLeod, S.; Dingley, K. H.; Turteltaub, K. W.; Lang, N. P.; Felton, J. S.
Abstract:
[2-(14)C]2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine ([14C]PhIP), a putative human carcinogenic heterocyclic amine found in well-done cooked meat, was administered orally to three colon cancer patients undergoing a partial colonectomy. Forty-eight to seventy-two hours prior to surgery, subjects received a 70-84 microg dose of 14C. Urine and blood were analyzed by HPLC for PhIP and PhIP metabolites. Metabolites were identified based on HPLC co-elution with authentic PhIP metabolite standards, mass spectral analysis and susceptibility to enzymatic cleavage. In two subjects, approximately 90% of the administered [14C]PhIP dose was eliminated in the urine, whereas in the other, only 50% of the dose was found in the urine. One subject excreted three times more radioactivity in the first 4 h than did the others. Twelve radioactive peaks associated with PhIP were detected in the urine samples. The relative amount of each metabolite varied by subject, and the amounts of each metabolite within subjects changed over time. In all three subjects the most abundant urinary metabolite was identified as 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine-N2-glucuron ide (N-hydroxy-PhIP-N2-glucuronide), accounting for 47-60% of the recovered counts in 24 h. PhIP accounted for
Published:
1999-04
Title:
A very low-fat diet is not associated with improved lipoprotein profiles in men with a predominance of large, low-density lipoproteins
Authors:
Dreon, D. M.; Fernstrom, H. A.; Williams, P. T.; Krauss, R. M.
Abstract:
BACKGROUND: We found previously that men with a predominance of large LDL particles (phenotype A) consuming high-fat diets (40-46% fat) show less lipoprotein benefits of low-fat diets (20-24% fat) than do men with a high-risk lipoprotein profile characterized by a predominance of small LDL (phenotype B). Furthermore, one-third of men with phenotype A consuming a high-fat diet converted to phenotype B with a low-fat diet. OBJECTIVE: We investigated effects of further reduction in dietary fat in men with persistence of LDL subclass phenotype A during both high- and low-fat diets. DESIGN: Thirty-eight men who had shown phenotype A after 4-6 wk of both high- and low-fat diets consumed for 10 d a 10%-fat diet (2.7% saturates) with replacement of fat with carbohydrate and no change in cholesterol content or ratio of polyunsaturates to saturates. RESULTS: In 26 men, phenotype A persisted (stable A group) whereas 12 converted to phenotype B (change group). LDL cholesterol did not differ from previous values for 20-24%-fat diets in either group, whereas in the change group there were higher concentrations of triacylglycerol and apolipoprotein B; greater mass of HDL, large LDL-I, small LDL-III and LDL-IV, and HDL3; lower concentrations of HDL cholesterol, apolipoprotein A-I; and lower mass of large LDL-I and HDL2. CONCLUSIONS: There is no apparent lipoprotein benefit of reduction in dietary fat from 20-24% to 10% in men with large LDL particles: LDL-cholesterol concentration was not reduced, and in a subset of subjects there was a shift to small LDL along with increased triacylglycerol and reduced HDL-cholesterol concentrations.
Published:
1999-03
Title:
Effects of fatty acids and ketone bodies on basal insulin secretion in type 2 diabetes
Authors:
Boden, G.; Chen, X.
Abstract:
The objective of this study was to assess the role of free fatty acids (FFAs) as insulin secretagogues in patients with type 2 diabetes. To this end, basal insulin secretion rates (ISR) in response to acute increases in plasma FFAs were evaluated in patients with type 2 diabetes and in age- and weight-matched nondiabetic control subjects during 1) intravenous infusion of lipid plus heparin (L/H), which stimulated intravascular lipolysis, and 2) the FFA rebound, which followed lowering of plasma FFAs with nicotinic acid (NA) and was a consequence of increased lipolysis from the subject's own adipose tissue. At comparable euglycemia, diabetic patients had similar ISR but higher plasma beta-hydroxybutyrate (beta-OHB) levels during L/H infusion and higher plasma FFA and beta-OHB levels during the FFA rebound than nondiabetic control subjects. Correlating ISR with plasma FFA plus beta-OHB levels showed that in response to the same changes in FFA plus beta-OHB levels, diabetic patients secreted approximately 30% less insulin than nondiabetic control subjects. In addition, twice as much insulin was secreted during L/H infusion as during the FFA rebound in response to the same FFA/beta-OHB stimulation by both diabetic patients and control subjects. Glycerol, which was present in the infused lipid (272 mmol/l) did not affect ISR. We concluded that 1) assessment of FFA effects on ISR requires consideration of effects on ISR by ketone bodies; 2) ISR responses to FFA/beta-OHB were defective in patients with type 2 diabetes (partial beta-cell lipid blindness), but this defect was compensated by elevated plasma levels of FFAs and ketone bodies; and 3) approximately two times more insulin was released per unit change in plasma FFA plus beta-OHB during L/H infusion than during the FFA rebound after NA. The reason for this remains to be explored.
Published:
1999-03
Title:
High glycemic index foods, overeating, and obesity
Authors:
Ludwig, D. S.; Majzoub, J. A.; Al-Zahrani, A.; Dallal, G. E.; Blanco, I.; Roberts, S. B.
Abstract:
OBJECTIVE: The prevalence of obesity has increased dramatically in recent years. However, the role of dietary composition in body weight regulation remains unclear. The purpose of this work was to investigate the acute effects of dietary glycemic index (GI) on energy metabolism and voluntary food intake in obese subjects. METHODS: Twelve obese teenage boys were evaluated on three separate occasions using a crossover study protocol. During each evaluation, subjects consumed identical test meals at breakfast and lunch that had a low, medium, or high GI. The high- and medium-GI meals were designed to have similar macronutrient composition, fiber content, and palatability, and all meals for each subject had equal energy content. After breakfast, plasma and serum concentrations of metabolic fuels and hormones were measured. Ad libitum food intake was determined in the 5-hour period after lunch. RESULTS: Voluntary energy intake after the high-GI meal (5.8 megajoule [mJ]) was 53% greater than after the medium-GI meal (3.8 mJ), and 81% greater than after the low-GI meal (3.2 mJ). In addition, compared with the low-GI meal, the high-GI meal resulted in higher serum insulin levels, lower plasma glucagon levels, lower postabsorptive plasma glucose and serum fatty acids levels, and elevation in plasma epinephrine. The area under the glycemic response curve for each test meal accounted for 53% of the variance in food intake within subjects. CONCLUSIONS: The rapid absorption of glucose after consumption of high-GI meals induces a sequence of hormonal and metabolic changes that promote excessive food intake in obese subjects. Additional studies are needed to examine the relationship between dietary GI and long-term body weight regulation.
Published:
1999-03
Title:
Relationship of glucose and insulin levels to the risk of myocardial infarction: a case-control study
Authors:
Gerstein, Hertzel C; Pais, Prem; Pogue, Janice; Yusuf, Salim
Abstract:
OBJECTIVE To assess the relationship between dysglycemia and myocardial infarction in nondiabetic individuals. BACKGROUND Nondiabetic hyperglycemia may be an important cardiac risk factor. The relationship between myocardial infarction and glucose, insulin, abdominal obesity, lipids and hypertension was therefore studied in South Asians—a group at high risk for coronary heart disease and diabetes. METHODS Demographics, waist/hip ratio, fasting blood glucose (FBG), insulin, lipids and glucose tolerance were measured in 300 consecutive patients with a first myocardial infarction and 300 matched controls. RESULTS Cases were more likely to have diabetes (OR 5.49; 95% CI 3.34, 9.01), impaired glucose tolerance (OR 4.08; 95% CI 2.31, 7.20) or impaired fasting glucose (OR 3.22; 95% CI 1.51, 6.85) than controls. Cases were 3.4 (95% CI 1.9, 5.8) and 6.0 (95% CI 3.3, 10.9) times more likely to have an FBG in the third and fourth quartile (5.2– 6.3 and Ͼ6.3 mmol/l); after removing subjects with diabetes, impaired glucose tolerance and impaired fasting glucose, cases were 2.7 times (95% CI 1.5– 4.8) more likely to have an FBG Ͼ5.2 mmol/l. A fasting glucose of 4.9 mmol/l best distinguished cases from controls (OR 3.42; 95% CI 2.42, 4.83). Glucose, abdominal obesity, lipids, hypertension and smoking were independent multivariate risk factors for myocardial infarction. In subjects without glucose intolerance, a 1.2 mmol/l (21 mg/dl) increase in postprandial glucose was independently associated with an increase in the odds of a myocardial infarction of 1.58 (95% CI 1.18, 2.12). CONCLUSIONS A moderately elevated glucose level is a continuous risk factor for MI in nondiabetic South Asians with either normal or impaired glucose tolerance. (J Am Coll Cardiol 1999;33:612–9) © 1999 by the American College of Cardiology
Published:
1999-03
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