Alternative Dietary Strategies Research Articles

The low-carbohydrate diet and cardiovascular risk factors: Evidence from epidemiologic studies

AimsObesity is an important public health issue because of its high prevalence and concomitant increase in risk of cardiovascular diseases. Low carbohydrate diets are popular for weight loss and weight management but are not recommended in leading guidelines due to the perception that increases in dietary fat intake may lead to an adverse cardiovascular risk profile. To clarify the effects of a low-carbohydrate diet for weight loss on cardiovascular disease risk factors as compared to a low fat diet for weight loss, we systematically reviewed data from randomized controlled clinical trials and large observational studies. Data synthesisWe searched the MEDLINE database (Jan 1966–Nov 2013) to identify studies that examined a low-carbohydrate diet as compared to a low-fat diet for weight loss or the improvement of cardiovascular disease risk factors. ConclusionsRecent randomized controlled trials document that low-carbohydrate diets not only decrease body weight but also improve cardiovascular risk factors. In light of this evidence from randomized controlled trials, dietary guidelines should be re-visited advocating a healthy low carbohydrate dietary pattern as an alternative dietary strategy for the prevention of obesity and cardiovascular disease risk factors.

A Mediterranean diet improves HbA1c but not fasting blood glucose compared to alternative dietary strategies: a network meta‐analysis

Overweight or obese individuals with type 2 diabetes are encouraged to lose weight for optimal glucose management, yet many find this difficult. Determining whether alterations in dietary patterns irrespective of weight loss can aid glucose control has not been fully investigated. We conducted a systematic review and meta-analysis aiming to determine the effects of a Mediterranean diet compared to other dietary interventions on glycaemic control irrespective of weight loss. Electronic databases were searched for controlled trials that included a Mediterranean diet intervention. The interventions included all major components of the Mediterranean diet and were carried out in free-living individuals at high risk or diagnosed with type 2 diabetes. Network meta-analysis compared all interventions with one another at the same time as maintaining randomisation. Analyses were conducted within a Bayesian framework. Eight studies met the inclusion criteria, seven examined fasting blood glucose (n = 972), six examined fasting insulin (n = 1330) and three examined HbA1c (n = 487). None of the interventions were significantly better than the others in lowering glucose parameters. The Mediterranean diet reduced HbA1c significantly compared to usual care but not compared to the Palaeolithic diet. The effect of alterations in dietary practice irrespective of weight loss on glycaemic control cannot be concluded from the present review. The need for further research in this area is apparent because no firm conclusions about relative effectiveness of interventions could be drawn as a result of the paucity of the evidence.

An Alternative Dietary Strategy to Make Weight While Improving Mood, Decreasing Body Fat, and Not Dehydrating: A Case Study of a Professional Jockey

Professional jockeys are unique among weight-making athletes, as they are often required to make weight daily and, in many cases, all year-round. Common methods employed by jockeys include dehydration, severe calorie restriction, and sporadic eating, all of which have adverse health effects. In contrast, this article outlines a structured diet and exercise plan, employed by a 22-yr-old professional National Hunt jockey in an attempt to reduce weight from 70.3 to 62.6 kg, that does not rely on any of the aforementioned techniques. Before the intervention, the client's typical daily energy intake was 8.2 MJ (42% carbohydrate [CHO], 36% fat, 22% protein) consumed in 2 meals only. During the 9-wk intervention, daily energy intake was approximately equivalent to resting metabolic rate, which the athlete consumed as 6 meals per day (7.6 MJ, 46% CHO, 19% fat, 36% protein). This change in frequency and composition of energy intake combined with structured exercise resulted in a total body-mass loss of 8 kg, corresponding to reductions in body fat from 14.5% to 9%. No form of intentional dehydration occurred throughout this period, and mean urine osmolality was 285 mOsm/kg (SD 115 mOsm/kg). In addition, positive changes in mood scores (BRUMS scale) also occurred. The client was now able to ride light for the first time in his career without dehydrating, thereby challenging the cultural practices inherent in the sport.

Chronic high-carbohydrate, high-fat feeding in rats induces reversible metabolic, cardiovascular, and liver changes

Age-related physiological changes develop at the same time as the increase in metabolic syndrome in humans after young adulthood. There is a paucity of data in models mimicking chronic diet-induced changes in human middle age and interventions to reverse these changes. This study measured the changes during chronic consumption of a high-carbohydrate (as cornstarch), low-fat (C) diet and a high-carbohydrate (as fructose and sucrose), high-fat (H) diet in rats for 32 wk. C diet feeding induced changes without metabolic syndrome, such as disproportionate increases in total body lean and fat mass, reduced bone mineral content, cardiovascular remodeling with increased systolic blood pressure, left ventricular and arterial stiffness, and increased plasma markers of liver injury. H diet feeding induced visceral adiposity with reduced lean mass, increased lipid infiltration in the skeletal muscle, impaired glucose and insulin tolerance, cardiovascular remodeling, hepatic steatosis, and increased infiltration of inflammatory cells in the heart and the liver. Chia seed supplementation for 24 wk attenuated most structural and functional modifications induced by age or H diet, including increased whole body lean mass and lipid redistribution from the abdominal area, and normalized the chronic low-grade inflammation induced by H diet feeding; these effects may be mediated by increased metabolism of anti-inflammatory n-3 fatty acids from chia seed. These results suggest that chronic H diet feeding for 32 wk mimics the diet-induced cardiovascular and metabolic changes in middle age and that chia seed may serve as an alternative dietary strategy in the management of these changes.

Consumption of plant sterols in Belgium: consumption patterns of plant sterol-enriched foods in Flanders, Belgium

The present study describes the consumption of foods enriched with plant sterols (PS) and supplements containing PS, and evaluates PS intakes via the current consumption and for specific consumption scenarios. A market inventory was performed to collate different PS-enriched food items and supplements available in Belgium. An FFQ was developed to investigate the consumption of PS-enriched foods and supplements. A total of 139 pre-school children (2·5-7 years old) and 569 adults (308 women and 261 men) living in Flanders (the northern, Dutch-speaking part of Belgium) participated in the study. Of these, 21 % (Flemish pre-school children) and 28·5 % (Flemish adults) consume PS-enriched food products, leading to a mean PS intake in the consumer group of 0·70 (sd 0·61) g/d for pre-school children and 1·51 (sd 1·42) g/d for adults. Of the adult PS consumers, 23·2 % did not suffer from elevated blood cholesterol levels; 50 % of them had a PS intake less than or equal to 1 g/d and 16·4 % had a PS intake above 3 g/d and 7·8 % even had an intake above 4 g/d. Scenario studies assessed the intake when all Belgian adults would consume PS-enriched margarines without (scenario 1) or with (scenario 2) a daily consumption of a PS-enriched yoghurt drink. This resulted in an intake above 3 g/d in 17 % (women) and 29 % (men) for scenario 1 and 40 % (women) and 53 % (men) for scenario 2. The results indicate that PS-enriched food products are also consumed by the non-target group. Efficient communication tools are needed to inform consumers better about the target group of PS-enriched products, the advised dose per day and alternative dietary strategies to lower the blood cholesterol level.

Dietary Glycemic Index: Health Implications

Weight loss can be achieved by any means of energy restriction, but the challenge is to achieve sustainable weight loss and prevent weight “creep” without increasing the risk of chronic disease. The modest success of low fat diets has prompted research on alternative dietary strategies, including high protein diets and low glycemic index (GI) diets. Conventional high carbohydrate diets, even when based on wholegrain foods, increase postprandial glycemia and insulinemia and may compromise weight control via mechanisms related to appetite stimulation, fuel partitioning, and metabolic rate. This paper makes the case for the benefits of low glycemic index diets over higher protein diets. Both strategies are associated with lower postprandial glycemia, and both are commonly labeled as “low glycemic load,” but the long-term health effects are likely to be different. A large body of evidence, which now comprises observational prospective cohort studies, randomized controlled trials, and mechanistic experiments in animal models, provides robust support for low GI carbohydrate diets in the prevention of obesity, diabetes, and cardiovascular disease. Although lower carbohydrate, higher protein diets increase the rate of weight loss, cohort studies and meta-analyses of clinical trials suggest the potential for increased mortality.

Mixotrophy: a widespread and important ecological strategy for planktonic and sea-ice nanoflagellates in the Ross Sea, Antarctica

Mixotrophic nanoflagellates (MNF) were quantified in plankton and sea ice of the Ross Sea, Antarctica, during austral spring. Tracer experiments using fluorescently labeled bacteria (FLB) were conducted to enumerate MNF and determine their contribution to total chloroplastidic and total bacterivorous nanoflagellates. Absolute abundances of MNF were typically <200 ml -1 in plankton assemblages south of the Polar Front, but they comprised 8 to 42% and 3 to 25% of bacterivorous nanoflagellates in the water column and ice cores, respectively. Moreover, they represented up to 10% of all chloroplastidic nanoflagellates in the water column when the prymnesiophyte Phaeocys- tis antarctica was blooming (up to 23% if P. antarctica, which did not ingest FLB, was excluded from calculations). In ice cores, MNF comprised 5 to 10% of chloroplastidic nanoflagellates. The highest proportions of MNF were found in some surface water samples and in plankton assemblages beneath ice, suggesting a potentially large effect as bacterial grazers in those locations. This study is the first to report abundances and distributions of mixotrophic flagellates in the Southern Ocean. The presence of MNF in every ice and water sample examined suggests that mixotrophy is an important alternative dietary strategy in this region.

Carbohydrates--the good, the bad and the whole grain.

Weight loss can be achieved by any means of energy restriction, but the challenge is to achieve sustainable weight loss and prevent weight 'creep' without increasing the risk of chronic disease. The modest success of low fat diets has prompted research on alternative dietary strategies including high protein diets and low glycemic index (GI) diets. Conventional high carbohydrate diets, even when based on whole grain foods, increase postprandial glycaemia and insulinemia and may compromise weight control via mechanisms relating to appetite stimulation, fuel partitioning and metabolic rate. This paper makes the case for the benefits of low glycemic index diets over higher protein diets. Both strategies are associated with lower postprandial glycemia and both are commonly labelled as 'low glycemic load' but the long-term health effects are likely to be different. There is now a large body of evidence comprising observational prospective cohort studies, randomised controlled trials and mechanistic experiments in animal models, that provides robust support for low GI carbohydrate diets in the prevention of obesity, diabetes and cardiovascular disease. While lower carbohydrate, higher protein diets also increase the rate of weight loss, cohort studies and meta-analyses of clinical trials suggest the potential for increased mortality.

Lipid lowering effects of Momordica charantia (Bitter Melon) in HIV‐1‐protease inhibitor‐treated human hepatoma cells, HepG2

1. Hyperlipidemic effects of HIV-1-protease inhibitors (PI) are associated with increased hepatic production of triglyceride (TG)-rich lipoproteins, rather than lipoprotein clearance. PI are known to increase apolipoprotein B (apoB) secretion, apoC-III mRNA expression and decrease apoA-1 secretion. Nutritional therapy remains an important strategy to manage PI-associated hyperlipidemia. 2. This study investigated the in vitro efficacy of Asian vegetable, Momordica charantia or bitter melon (BM) to ameliorate PI-associated apoB and lipid abnormalities in HepG2 cells. 3. Our study demonstrates that bitter melon juice (BMJ) significantly reduced apoB secretion and apoC-III mRNA expression and normalized apoA-I expression in PI-treated HepG2 cells. BMJ also significantly reduced cellular TG and microsomal TG transfer protein, suggesting that lipid bioavailability and lipidation of apoB assembly may play a role in decreased apoB secretion. 4. Identifying molecular targets of BM may offer alternative dietary strategies to decrease PI-associated hyperlipidemia and improve quality of life among HIV-1-infected patients.

Induced moulting issues and alternative dietary strategies for the egg industry in the United States

Induced moulting issues and alternative dietary strategies for the egg industry in the United States

Induced moulting issues and alternative dietary strategies for the egg industry in the United States

The United States (U.S.) poultry industry continues to implement induced moulting to extend egg production in commercial laying flocks. Achieving an optimal moult requires dietary manipulation to cause a complete regression of the reproductive organs and cessation of egg production. This is followed by rejuvenation and initiation of an additional egg laying cycle. Currently feed withdrawal is the primary means to initiate moult and is regarded as an optimal approach for achieving post-moult performance. However, removal of feed can lead to potential physiological stress in laying hens as well as an increased susceptibility to Salmonella enteritidis colonization and invasion. To retain the ecological benefits of induced moult will require development, testing and implementation of alternative dietary approaches that minimizes these problems and increase the egg production and egg quality benefits associated with the additional egg laying cycles. Strategies for accomplishing this are discussed.

Induced moulting issues and alternative dietary strategies for the egg industry in the United States

Induced moulting issues and alternative dietary strategies for the egg industry in the United States

The effect of diet on plasma lipids, lipoproteins, and coronary heart disease

The role that diet plays in the management of plasma lipid levels is discussed in this review. It has long been recognized that saturated fatty acids and cholesterol raise the plasma cholesterol level whereas polyunsaturated fatty acids lower it. Recently, the effects of other dietary constituents in the management of plasma lipid levels have been established. In particular, monounsaturated fatty acids, soluble fiber, and vegetarian diets favorably affect plasma lipid levels. Overweight and obesity adversely affect plasma lipid levels. Omega-3 fatty acids are hypotriglyceridemic, and high carbohydrate diets low in saturated fatty acids are hypocholesterolemic. Further work is required to establish the long-term consequences of alcohol and coffee consumption on the plasma lipid response. A variety of alternative dietary strategies can be employed in conjunction with traditional dietary recommendations (i.e., reduce total fat, especially saturated fatty acids and dietary cholesterol) for the management of plasma lipid levels. The expected plasma total cholesterol (specifically low-density-lipoprotein cholesterol) reduction is approximately 10% to 20% when dietary saturated fatty acids and cholesterol are decreased to ≤7% of calories and ≤200 mg of cholesterol per day. Further dietary modifications, such as increasing soluble fiber, may lead to additional reductions of 1 % to 10% in plasma total cholesterol. J Am Diet Assoc 88:1373, 1988.

Income and dietary adequacy in an agricultural community

Although many studies as well as conventional wisdom suggest that increases in income result in improved diet and nutritional status in rural areas of developing countries, several recent studies have failed to demonstrate such a relationship. In this paper the relationships between material wealth and income and dietary strategies are examined for an agricultural community in rural Mexico. A superficial examination focusing on summary indices of dietary adequacy frequently cited in the literature and indices of wealth and income demonstrates a positive relationship between them in this community. However, an examination of the same data emphasizing alternative dietary strategies to achieve nutritional adequacy shows a more complex picture. Increasing income is associated with consumption of purchased foods especially foods of animal origin, and is not associated with the consumption of staple foods produced within the household. Diets dependent on purchased foods do not necessarily meet nutritional needs more adequately than diets which rely on agricultural products and gathered foods. Among the implications of this research are a need for a method of analysis which focuses on alternative nutritional strategies available in particular settings, and a need to reassess the relative importance of income generating activities and subsistence agriculture in areas undergoing agricultural change.