Dietary Means Research Articles

Means to improve the nutritive value of flaxseed for broiler chickens: The effect of particle size, enzyme addition, and feed pelleting

Three experiments were conducted to explore dietary means (particle size, enzyme addition, bile salts addition, and feed pelleting) of minimizing the antinutritive effects of cell wall-nonstarch polysaccharides of flaxseed. Broiler chickens were fed corn-soybean meal-based diets containing 15% of full-fat flaxseed from 5 to 18 d. The effects of 2 enzyme preparations containing viscosity-reducing or cell wall-degrading activities on growth performance and nutrient digestibility were evaluated in experiment 1. Enzyme addition had beneficial effects (P<0.05) in increasing nonstarch polysaccharide digestibility and reducing intestinal viscosity. However, no differences in growth performance or fat digestibility were observed between the enzyme types. Therefore, the enzyme supplement containing both viscosity-reducing and cell wall-degrading activities was used in subsequent studies. A 2x2x2 factorial arrangement was used in experiment 2 to investigate the effects of particle size (coarse vs. fine), enzyme supplementation, and bile salt addition on the nutritive value of flaxseed for broiler chickens. In experiment 3, a 4x2 factorial arrangement was used to further investigate the effects of feed processing (whole seed, coarsely ground seed, and finely ground seed in pelleted diets or finely ground seed in mash diets) and enzyme addition on growth performance and fat utilization. Bile salt addition did not improve fat digestibility. Particle size reduction via grinding had no significant effect on growth performance no matter if present in the mash or pelleted diets. When compared with grinding, feed pelleting showed more pronounced and beneficial effects on growth performance particularly when whole, intact seeds were used, indicating a potential for using whole flaxseed in the pelleted diets. Enzyme addition resulted in an increase in total tract fat digestibility by 3 to 6%, which was reflected in an improved feed conversion ratio by 1 to 3%, regardless of the processing method used (P<0.05). In conclusion, enzyme addition and feed pelleting offer practical solutions to improve the nutritive value of flaxseed for broiler chickens.

The effect of dietary laminarin and fucoidan in the diet of the weanling piglet on performance, selected faecal microbial populations and volatile fatty acid concentrations

A 2 × 2 factorial experiment (n = 12 replicates per treatment, 4 pigs per replicate) was performed to investigate the effects of seaweed extracts, laminarin (derived ß-glucans) and fucoidan (sulphated polysaccharides), independently or in combination on post-weaning piglet performance and selected microbial populations. At weaning, the piglets (24 days of age, 6.4 kg live weight) were assigned to one of the four dietary treatments: (T1) basal diet, (T2) basal diet with 300 p.p.m. laminarin, (T3) basal diet with 240 p.p.m. fucoidan, (T4) basal diet with 300 p.p.m. laminarin and 240 p.p.m. fucoidan. Pigs offered diets supplemented with laminarin had an increased daily gain (P < 0.01), and gain-to-feed ratio (P < 0.05) compared to pigs offered diets without laminarin supplementation during the experimental period (days 0 to 21). Pigs offered laminarin-supplemented diets had an increased faecal dry matter and reduced diarrhoea (P < 0.05) during the critical 7 to 14 day period. Pigs offered diets containing laminarin had reduced faecal Escherichia coli populations. There was a significant interaction (P < 0.01) on faecal Lactobacilli populations between laminarin and fucoidan. Pigs offered the fucoidan diet had an increased Lactobacilli population compared to pigs offered the basal diet. However, there was no effect of fucoidan on faecal Lactobacilli populations when laminarin was added. Overall, the reduction in E. coli population and the increase in daily gain suggest that laminarin may provide a dietary means to improve gut health after weaning.

Impact of dietary polyphenols on human platelet function – A critical review of controlled dietary intervention studies

Cardiovascular disease is a chronic disease influenced by many factors, with activated blood platelets being one of them. Platelets play a central role in the formation of plaques within blood vessels, contributing to early inflammatory events. Consumption of diets rich in plant-based products protects against the development of cardiovascular disease. Polyphenols, which are secondary plant metabolites found in a wide range of foodstuffs and beverages, may be partially responsible for these effects. Their protective properties include inhibitory effects on platelet function in vitro and in vivo. However, the bioavailability of many polyphenols is poor and it is unclear whether sufficient quantities can be obtained by dietary means to exert protective effects. Consequently, this review summarizes 25 well-controlled human intervention studies examining the effect of polyphenol-rich diets on platelet function. These studies report a huge variety of research methods, study designs, and study subjects, resulting in controversial assertions. One consistent finding is that cocoa-related products, however, have platelet-inhibiting effects when consumed in moderate amounts. To assess whether other classes of dietary polyphenols, or their metabolites, also beneficially affect platelet function requires more well-controlled intervention studies as well as the adoption of more uniform methods to assess platelet aggregation and activation.

The effect of dietary Laminaria-derived laminarin and fucoidan on nutrient digestibility, nitrogen utilisation, intestinal microflora and volatile fatty acid concentration in pigs.

In experiment 1, 30 boars were assigned to one of five treatments (n = 6): T1, 0 g kg(-1) seaweed extract (SWE); T2, 0.7 g kg(-1) SWE; T3, 1.4 g kg(-1) SWE; T4, 2.8 g kg(-1) SWE and T5, 5.6 g kg(-1) SWE. The extract contained laminarin and fucoidan only and was extracted from Laminaria spp. In experiment 2, 28 boars were assigned, in a 2 x 2 factorial to one of four treatments (n = 7): T1, control; T2, control plus 300 mg laminarin; T3, control plus 240 mg fucoidan; T4, control plus 300 mg laminarin and 240 mg fucoidan kg(-1) diet. In experiment 1 there was a response to SWE on colonic Bifidobacterium spp. (P < 0.01 quadratic), Enterobacterium spp. (quadratic P < 0.05) and on caecal Enterobacterium spp. (quadratic P < 0.05). In experiment 2 there was an interaction (P < 0.05) between laminarin and fucoidan supplementation on Enterobacterium spp. in the proximal and distal colon. Pigs offered laminarin had reduced Enterobacterium spp. compared with pigs offered the control diet. However, the combination of laminarin and fucoidan had increased Enterobacterium spp. compared with alone. Pigs offered diets containing fucoidan had increased Lactobacilli spp. in the proximal colon (P < 0.05) and distal colon (P < 0.001) compared with non-fucoidan diets. Overall, the reductions in intestinal Enterobacterium spp. and increases in Lactobacilli spp. obtained suggest that laminarin and fucoidan may provide a dietary means to improve gut health in pigs.

Diet-induced acidosis: is it real and clinically relevant?

The concept of diet-induced 'acidosis' as a cause of disease has been a subject of interest for more than a century. The present article reviews the history of our evolving understanding of physiological pH, the physiological support for the concept of 'acidosis', the causes of acidosis, how it is recognised, its short-term effects as well as the long-term clinical relevance of preventative measures, and the research support for normalisation of pH. Further, we suggest differentiation of the terms 'acidosis' and 'acidaemia' as a way to resolve the conflation of these topics which has led to confusion and controversy. The available research makes a compelling case that diet-induced acidosis, not diet-induced acidaemia, is a real phenomenon, and has a significant, clinical, long-term pathophysiological effect that should be recognised and potentially counterbalanced by dietary means.

An Ethical and Policy Analysis of Elective Transplantation for Metabolic Conditions Diagnosed by Newborn Screening

Liver transplantation (LT) is a therapeutic option for some metabolic conditions; however, unlike other causes of liver failure, some of these conditions can be treated with dietary means. For those conditions, LT has been described as “elective.”1 Both maple syrup urine disease (MSUD) and methylmalonic acidemia (MMA) are 2 such metabolic conditions. The main ethical issue is a justice concern: whether to list children and adults with MSUD and MMA for an “elective” LT when other patients with non-metabolic liver failure die because there is an inadequate supply of deceased donor liver grafts.

Overview of the LDL receptor: relevance to cholesterol metabolism and future approaches for the treatment of coronary heart disease

Since the discovery of the low-density lipoprotein (LDL) receptor over 30 years ago manipulation of its activity has been pursued through dietary and pharmacological means with the goal of reducing LDL cholesterol levels. This has proven to be one of the most widely implemented and beneficial interventions to reduce LDL cholesterol levels and the incidence of cardiovascular death. This review provides an overview of the LDL receptor and its role in regulating whole body cholesterol homeostasis and LDL cholesterol levels. New findings on regulation of the LDL receptor are discussed and how they can be used to develop novel therapeutics to reduce cardiovascular risk.

Remodeling of Retinal Fatty Acids in an Animal Model of Diabetes

OBJECTIVEThe results of the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications cohort study revealed a strong association between dyslipidemia and the development of diabetic retinopathy. However, there are no experimental data on retinal fatty acid metabolism in diabetes. This study determined retinal-specific fatty acid metabolism in control and diabetic animals.RESEARCH DESIGN AND METHODSTissue gene and protein expression profiles were determined by quantitative RT-PCR and Western blot in control and streptozotocin-induced diabetic rats at 3–6 weeks of diabetes. Fatty acid profiles were assessed by reverse-phase high-performance liquid chromatography, and phospholipid analysis was performed by nano-electrospray ionization tandem mass spectrometry.RESULTSWe found a dramatic difference between retinal and liver elongase and desaturase profiles with high elongase and low desaturase gene expression in the retina compared with liver. Elovl4, an elongase expressed in the retina but not in the liver, showed the greatest expression level among retinal elongases, followed by Elovl2, Elovl1, and Elovl6. Importantly, early-stage diabetes induced a marked decrease in retinal expression levels of Elovl4, Elovl2, and Elovl6. Diabetes-induced downregulation of retinal elongases translated into a significant decrease in total retinal docosahexaenoic acid, as well as decreased incorporation of very-long-chain polyunsaturated fatty acids (PUFAs), particularly 32:6n3, into retinal phosphatidylcholine. This decrease in n3 PUFAs was coupled with inflammatory status in diabetic retina, reflected by an increase in gene expression of proinflammatory markers interleukin-6, vascular endothelial growth factor, and intercellular adhesion molecule-1.CONCLUSIONSThis is the first comprehensive study demonstrating diabetes-induced changes in retinal fatty acid metabolism. Normalization of retinal fatty acid levels by dietary means or/and modulating expression of elongases could represent a potential therapeutic target for diabetes-induced retinal inflammation.

Vitamin D and the Parenteral Nutrition Patient

Vitamin D is a prohormone produced in the skin epidermis when irradiated with sunlight or ultraviolet light B. It is also absorbed from food or supplements. Vitamin D must be converted to 25-hydroxyvitamin D3 (circulating form) and finally to the hormone, 1a,25-dihydroxyvitamin D3, before it can function. This hormone acts through a single nuclear receptor. The details of these conversions and molecular biology of the action of vitamin D3 are summarized. The physiologic functions of vitamin D have been expanded beyond the mineralization of the skeleton to include modulation of the immune system, terminal differentiation in several tissues, suppression of malignant cells, and anabolic activity in the skeleton and in the renal-cardiovascular system. Epidemiologic studies have associated vitamin D deficiency with an increased risk of colorectal and breast cancers and an increased risk of autoimmune diseases, such as multiple sclerosis, type 1 diabetes, and cardiovascular events. Thus, vitamin D is essential not only for the skeleton but also many other organ systems. Recommendations for 25-hydroxyvitamin D3 levels for PN patients are presented.

Homocysteine-mediated thrombosis and angiostasis in vascular pathobiology.

The mechanisms by which homocysteine contributes to atherothrombosis are complex and their in vivo relevance uncertain. In this issue of the JCI, Jacovina and colleagues report a unique in vivo mechanism by which homocysteine may contribute to vascular disease (see the related article beginning on page 3384). This group had previously reported that homocysteine impairs endothelial cell surface plasminogen activation by posttranslationally modifying annexin A2, the coreceptor for plasminogen and tissue plasminogen activator. They now show that an annexin A2-deficient mouse rendered hyperhomocysteinemic by dietary means has impaired fibrinolysis, perivascular fibrin persistence, and attenuated angiogenesis (angiostasis). Potential mechanisms by which homocysteine-dependent changes in endothelial phenotype link thrombosis to angiostasis are reviewed and their relationship to homocysteine-dependent vascular disease considered.

A meta-analysis of feed digestion in dairy cows. 1. The effects of forage and concentrate factors on total diet digestibility

A meta-analysis based on published experiments with lactating dairy cows was conducted to study the effects of dietary forage and concentrate factors on apparent total diet digestibility. A data set was collected that included a total of 497 dietary treatment means from 92 studies. The diets were based on grass silage or on legume or whole-crop cereal silages partly or completely substituted for grass silage. The silages were supplemented with concentrates given at a flat rate within a dietary comparison. For the statistical evaluation, the data were divided into 5 subsets to quantify silage (digestibility, 42 diets in 17 studies; fermentation characteristics, 108 diets in 39 studies) and concentrate (amount of supplementation, 142 diets in 59 studies; concentration of crude protein, 215 diets in 82 studies; carbohydrate composition, 66 diets in 23 studies) factors on total diet digestibility. The diet digestibility of dairy cows was determined by total fecal collection or by using acid-insoluble ash as an internal marker. Diet organic matter digestibility (OMD) at a maintenance level of feeding (OMDm) was estimated using sheep in vivo or corresponding in vitro digestibility values for the forage and reported ingredient and chemical composition values, with tabulated digestibility coefficients for the concentrate components of the diet. A mixed model regression analysis was used to detect the responses of different dietary factors on apparent total diet digestibility. Improved silage OMDm resulting from earlier harvest was translated into improved production-level OMD in cows (OMDp). The effects of silage fermentation characteristics on OMDp were quantitatively small, although sometimes significant. Concentrate supplementation improved total diet OMDm, but this was not realized in lactating dairy cows because of linearly decreased neutral detergent fiber (NDF) digestibility as concentrate intake increased. Increasing the concentrate crude protein amount quadratically improved OMDp in cows, with the response being mostly due to improved NDF digestibility. Replacement of starchy concentrates with fibrous by-products slightly decreased OMDp but tended to improve NDF digestibility. The true digestibility of cell solubles (OM – NDF) estimated by the Lucas test both from all data and from the data subsets was not significantly different from 1.00, suggesting that responses in OMDp of dairy cows are mediated through changes in the concentration and digestibility of NDF.

A meta-analysis of feed digestion in dairy cows. 2. The effects of feeding level and diet composition on digestibility

A meta-analysis based on published experiments with lactating dairy cows fed mainly grass silage-based diets was conducted to study the effects of intake, diet composition, and digestibility at a maintenance level of feeding on the apparent total diet digestibility. A data set that included a total of 497 dietary treatment means from 92 studies was collected and analyzed using mixed model regression analysis with a random study effect. Diet organic matter digestibility (OMD) in dairy cows at a production level (OMDp) was positively associated with OMD at maintenance (OMDm), but the slope was less than 1 (0.69). Diet OMDp decreased as feed intake increased, and diets with high OMDm exhibited greater depressions in digestibility with increased intake than did diets with low OMDm. Digestibility of organic matter and neutral detergent fiber (NDF) increased as dietary crude protein concentration increased, whereas increased concentrate fat decreased digestibility. Replacement of grass silage with whole-crop cereal silage was associated with a quadratic decrease in diet digestibility. Metabolic fecal output, defined as fecal organic matter minus NDF, averaged 95.8 (SE=0.65) g/kg of dry matter intake, and it was not influenced by intake or diet composition. Variation in OMDp in cows fed grass silage-based diets was therefore attributable to variation in dietary NDF concentration and NDF digestibility. Depression in digestibility of organic matter with increased intake was less than predicted by the National Research Council and Cornell Net Carbohydrate and Protein systems. The following 2-parameter model indicates that the difference between OMD estimated in sheep fed at maintenance compared with dairy cows at production level is related both to dry matter intake and digestibility at maintenance level: OMDp=257 (±43) + 0.685 (±0.054) × OMDm (g/kg of dry matter) – 2.6 (±0.44) × dry matter intake (kg/d); adjusted residual mean square error=8.4g/kg. It was concluded that diet digestibility in dairy cows can be predicted accurately and precisely from digestibility estimated at maintenance intake in sheep by using regression models including animal and dietary factors.

Rheuma und Entzündungskontrolle durch Ernährung

Research work of the last decade has revealed dietary options to attenuate inflammation in rheumatic diseases via the eicosanoid system. Dietary means are reduction of arachidonic acid intake with a modified lactovegetarian diet, increased intake of plant oils and fatty fish rich in omega-3 fatty acids, and ample antioxidant supply. This diet also is effective in preventing cardio-vascular diseases, which occur twice as frequently in patients with inflammatory rheumatic diseases compared to healthy controls. Nutrition always must be regarded an adjuvant therapy, becoming effective on inflammation only 3 months after initiation, and only thereafter anti-inflammatory drugs may be reduced or stopped, according to medical advice. Dietary therapy is complex in rheumatic diseases, as frequent co-morbidities, e. g. osteoporosis, intolerances of or sensitivities to individual nutrients, and adjustment of deficient or inappropriate nutrient intake, have to be considered. To optimize the outcome, treatment should be given to the patients in a team, consisting of e. g. rheumatologist, nutritionist, physiotherapist and psychotherapist. Interactions of these specialists are crucial for the success, and are trained in special seminars.

Milk production responses of primiparous and multiparous dairy cows to dose of conjugated linoleic acid consumed in rumen inert form

Conjugated linoleic acid (CLA) has the potential to be used as a dietary means of manipulating milk fat production of dairy cows to meet specified short-term targets, as in a supply-managed industry. An experiment was conducted to evaluate the dose-response to calcium salts of CLA fed as a top-dress on a corn- and alfalfa-based TMR. In two 5 × 5 Latin squares of 28-d periods, five primiparous and five multiparous cows were fed 0, 22, 45, 67 or 178 g d-1 CLA (29% trans-10, cis-12) as a calcium salt. Results from one multiparous cow on the 178 g d-1 treatment were removed from statistical analysis because milk production fell to 1.2 kg d-1 by the end of the period. On average, milk, lactose and protein yields increased at the lower doses of CLA and decreased to control levels at the highest dose. Milk fat yield declined progressively from 876 to 770, 689, 676 and 543 g d-1 on the five doses. Net energy balance of cows increased linearly from -1.5 Mcal d-1 on the control to 2.0 Mcal d-1 at 178 g d-1 CLA. The percentage depression in milk fat yield at different doses of trans-10, cis-12 CLA was described by the equation y = 54/(1 + 22.8/dose). Comparison with published literature suggested that feeding calcium salts of CLA was 30% as effective in depressing milk fat production as an abomasal infusion, due to rumen biohydrogenation and intestinal indigestibility.Key words: Milk composition, cattle, diet

Enriching M. sternomandibularis with [formula omitted]-tocopherol by dietary means does not protect against the lipid oxidation caused by high-pressure processing

We hypothesized that elevating the concentration of α -tocopherol in beef muscle tissue by dietary means would increase lipid stability following high-pressure processing. Beef M. sternomandibularis was obtained from cattle that had medium (4.92 μ g/g) and high (7.30 μ g/g) concentrations of α -tocopherol. Post-rigor, paired muscles samples were subjected to pressures of 0.1 (atmospheric), 200 or 800 MPa for 20 min at approximately 60 °C. Following high-pressure processing, measurements were made immediately (d 0) or on samples stored in the dark for 6 d at 4 °C (d 6). Intramuscular lipid was similar for each group (4.02% vs. 4.26%, respectively; P = 0.78), but lipid from the medium α -tocopherol muscle was more saturated and less monounsaturated than muscle from the high α -tocopherol group. High-pressure processing at 800 MPa and 60 °C did not reduce the amount of α -tocopherol but significantly reduced the concentration of linoleic acid (18:2 n−6) in muscle from both production groups of cattle. Thiobarbituric acid reactive substances increased linearly with treatment pressure only in d 6 samples (day × pressure interaction P = 0.0001) and were higher overall ( P = 0.02) in the high α -tocopherol muscle than in the medium α -tocopherol muscle. At d 6, lipid peroxides were decreased ( P = 0.007) by high-pressure treatment and were higher ( P < 0.0001) in the high α -tocopherol group than in the medium α -tocopherol group. Therefore, muscle from the high α -tocopherol cattle in this study had a greater accumulation of lipid peroxides by d 6, making the muscle from those cattle more susceptible to oxidation.

Dietary sources of lignans and isoflavones modulate responses to estradiol in estrogen reporter mice

Dietary phytoestrogens, such as the lignan metabolite enterolactone (ENL) and the isoflavone genistein (GEN), are suggested to modulate the risk of estrogen-dependent disease (e.g., breast cancer) through regulation of estrogen signaling. However, the effects of complex food items containing lignans or isoflavones on estrogen receptor (ER) transactivation have not been assessed so far. In this study, the modulation of ER-mediated signaling by dietary sources of lignans (cereals and flaxseed) and isoflavones (soy) was studied in vivo. Adult ovariectomized 3 x ERE-luciferase (luc) reporter mice received isocaloric diets supplemented with flaxseed, rye, wheat, or soy for 40 h or two weeks, and an additional group of mice was challenged with 17beta-estradiol (E(2)) following the two-week dietary intervention. In non-E(2)-treated mice, soy diet induced luc expression in liver, mammary gland, and pituitary gland while the other diets had no effects. Interestingly, all diets modulated the E(2)-induced luc expression. In particular rye diet efficiently reduced E(2)-induced luc expression as well as uterine growth, the hallmark of estrogen action in vivo. It is concluded that dietary sources of lignans and isoflavones can modulate estrogen signaling in vivo. The results suggest intriguing possibilities for the modulation of the risk of estrogen-dependent diseases by dietary means.

Rapid-acting insulin secretagogues: a clinical need?

The history of achieving adequate insulin secretion in Type 2 diabetes has interesting parallels with Type 1 diabetes. Initial insulin secretagogue therapy involved short-acting sulphonylureas--tolbutamide being introduced 40 years ago--and early insulin therapy used unmodified (soluble) insulin. Subsequently, long-acting sulphonylureas and insulin were introduced, but more recently short-acting agents have become popular again. This approach was endorsed by the European non-insulin-dependent diabetes mellitus guidelines of 1989/1993. The trend at present is to match modern rapid-acting agents (such as repaglinide or the rapid-acting insulin analogues) to physiological meal-time insulin requirements in both types of diabetes. The fundamental reasons for tailoring therapy to meal-times fall into two categories: a pathophysiological rationale and a behavioural rationale. The pathophysiological rationale for tailoring treatment to mealtimes is based on the importance of restoring the mealtime insulin secretion profiles of patients with Type 2 diabetes to physiological levels to re-establish the tight control of blood glucose levels seen in healthy individuals. The behavioural rationale is derived from the observation that most people with Type 2 diabetes are overweight and would like to reduce calorie consumption, but that the risk of hypoglycaemia does not allow them to be flexible over their day-to-day calorie intake. These observations suggest that the matching of a meal-time pharmacodynamic profile to a patient's eating habits would provide a knowledge-based rationale for achieving good blood glucose control once dietary means alone are inadequate. Evidently, this can be usefully combined with other pharmacological approaches (insulin sensitizers or basal insulin). The need for combination therapy is increasingly likely as the defect in insulin secretion progresses.

Dealing With A Controllable Risk Factor Like Diet In The Management Of Cardiovascular Disease

Cardiovascular disease (CVD) is a silent killer in Nigeria and many parts of the world. Certain factors increase the risk of CVD. While there are controllable factors that contribute and predispose to the development of CVD like diet, exercise, tobacco use, high blood pressure andobesity, there are uncontrollable factors like age, sex and heredity, which are out of the control of the individual. Freedom from CVD is an intricate interaction of many factors. Diet is one strong means of staying free of CVD. This paper posits that rather than calling for a complete boycott of red meat and poultry eggs, thereby throwing those involved in this line of business out of work, professionals involved in animal production, can resort to genetic, dietary, non-dietary, and pharmacological means of controlling cholesterol in meat and eggs. Even though CVD is more common among the aged, artherogenesis (the beginning of artery plaque formation) starts in early childhood. Education is a very important factor in our search for freedom from CVD. Medical personnel, human nutritionists, veterinarians and animal scientists should form a strong synergy in the fight against this scourge.

PRODUCTION of acute massive hepatic necrosis in rats by dietary means.

PRODUCTION of acute massive hepatic necrosis in rats by dietary means.

Diet and exercise in obese subjects: self-report versus controlled measurements.

Past decades have witnessed a continuing discussion on the relative role of food intake in the pathogenesis of obesity. Some observers argue that overeating is paramount; others claim that the obese are metabolically more efficient in energy utilization, and thus may not need as much food. There is a considerable amount of evidence that big people do need more food than those who are smaller and thinner. However, a recent study using advanced techniques has revealed a clear discrepancy between self-reported and actual energy intake and self-reported and actual physical activity in obese subjects, especially those who had great difficulty in losing weight by dietary means.