The Safe and Effective Use of Plant-Based Diets with Guidelines for Health Professionals.

Plant-based diets, defined here as including both vegan and lacto-ovo-vegetarian diets, are growing in popularity throughout the Western world for various reasons, including concerns for human health and the health of the planet. Plant-based diets are more environmentally sustainable than meat-based diets and have a reduced environmental impact, including producing lower levels of greenhouse gas emissions. Dietary guidelines are normally formulated to enhance the health of society, reduce the risk of chronic diseases, and prevent nutritional deficiencies. We reviewed the scientific data on plant-based diets to summarize their preventative and therapeutic role in cardiovascular disease, cancer, diabetes, obesity, and osteoporosis. Consuming plant-based diets is safe and effective for all stages of the life cycle, from pregnancy and lactation, to childhood, to old age. Plant-based diets, which are high in fiber and polyphenolics, are also associated with a diverse gut microbiota, producing metabolites that have anti-inflammatory functions that may help manage disease processes. Concerns about the adequate intake of a number of nutrients, including vitamin B12, calcium, vitamin D, iron, zinc, and omega-3 fats, are discussed. The use of fortified foods and/or supplements as well as appropriate food choices are outlined for each nutrient. Finally, guidelines are suggested for health professionals working with clients consuming plant-based diets.

Evidence summaries and recommendations from the international evidence-based guideline for the assessment and management of polycystic ovary syndrome: Lifestyle management.

Lifestyle is fundamental in chronic disease prevention and management, and it has been recommended as a first-line treatment in the Australian polycystic ovary syndrome (PCOS) guideline 2011. The first international evidence-based guideline on PCOS was developed in 2018, which expanded the scope and evidence in the Australian guideline. This paper summarizes the lifestyle recommendations and evidence summaries from the guideline. International multidisciplinary guideline development groups delivered the International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome 2018. The process followed the Appraisal of Guidelines for Research and Evaluation II and The Grading of Recommendations, Assessment, Development and Evaluation framework. Extensive communication and meetings addressed six prioritized clinical questions through five reviews. Evidence-based recommendations were formulated before consensus voting within the panel. Evidence shows the benefits of multicomponent lifestyle intervention, efficacy of exercise and weight gain prevention with no specific diet recommended. Lifestyle management is the first-line management in the intervention hierarchy in PCOS. Multicomponent lifestyle intervention including diet, exercise and behavioural strategies is central to PCOS management with a focus on weight and healthy lifestyle behaviours. The translation programme optimizes reach and dissemination for health professionals and consumers.

Exercise Recommendations for Women with Polycystic Ovary Syndrome: Is the Evidence Enough?

In this opinion piece, we summarize, discuss implications of implementation, and critically evaluate our 2018 evidence-based guideline recommendations for exercise and physical activity in women with polycystic ovary syndrome (PCOS). We developed recommendations as part of a larger international guideline development project. The overall guideline scope and priorities were informed by extensive health professional and consumer engagement. The lifestyle guideline development group responsible for the exercise recommendations included experts in endocrinology, exercise physiology, gynecology, dietetics, and obstetrics, alongside consumers. Extensive online communications and two face-to-face meetings addressed five prioritized clinical questions related to lifestyle, including the role of exercise as therapy for women with PCOS. The guideline recommendations were formulated based on one narrative and two evidence-based reviews, before consensus voting within the guideline panel. The development process was in accordance with the Appraisal of Guidelines for Research and Evaluation (AGREE) II, and used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework to assess evidence quality, desirable and undesirable consequences, feasibility, acceptability, cost, implementation, and recommendation strength. Given the evidence for exercise as therapy in PCOS being of low quality, a consensus recommendation was made based on current exercise guidelines for the general population. Women with PCOS and clinicians are forced to adopt generic approaches when recommending exercise therapy that perpetuates clinical management with pharmacological solutions. The current status of evidence highlights the need for greater international co-operation between researchers and funding agencies to address key clinical knowledge gaps around exercise therapy in PCOS to generate evidence for appropriate, scalable, and sustainable best practice approaches.

Dietary composition in the treatment of polycystic ovary syndrome: a systematic review to inform evidence-based guidelines.

While lifestyle management is recommended as first-line treatment of polycystic ovary syndrome (PCOS), the optimal dietary composition is unclear. The aim of this study was to compare the effect of different diet compositions on anthropometric, reproductive, metabolic, and psychological outcomes in PCOS. A literature search was conducted (Australasian Medical Index, CINAHL, EMBASE, Medline, PsycInfo, and EBM reviews; most recent search was performed January 19, 2012). Inclusion criteria were women with PCOS not taking anti-obesity medications and all weight-loss or maintenance diets comparing different dietary compositions. Studies were assessed for risk of bias. A total of 4,154 articles were retrieved and six articles from five studies met the a priori selection criteria, with 137 women included. A meta-analysis was not performed due to clinical heterogeneity for factors including participants, dietary intervention composition, duration, and outcomes. There were subtle differences between diets, with greater weight loss for a monounsaturated fat-enriched diet; improved menstrual regularity for a low-glycemic index diet; increased free androgen index for a high-carbohydrate diet; greater reductions in insulin resistance, fibrinogen, total, and high-density lipoprotein cholesterol for a low-carbohydrate or low-glycemic index diet; improved quality of life for a low-glycemic index diet; and improved depression and self-esteem for a high-protein diet. Weight loss improved the presentation of PCOS regardless of dietary composition in the majority of studies. Weight loss should be targeted in all overweight women with PCOS through reducing caloric intake in the setting of adequate nutritional intake and healthy food choices irrespective of diet composition.

Vitamin B12 and vegetarian diets.

Vitamin B12 is found almost exclusively in animal-based foods and is therefore a nutrient of potential concern for those following a vegetarian or vegan diet. Vegans, and anyone who significantly limits intake of animal-based foods, require vitamin B12-fortified foods or supplements. Vitamin B12 deficiency has several stages and may be present even if a person does not have anaemia. Anyone following a vegan or vegetarian diet should have their vitamin B12 status regularly assessed to identify a potential problem. A useful process for assessing vitamin B12 status in clinical practice is the combination of taking a diet history, testing serum vitamin B12 level and testing homocysteine, holotranscobalamin II or methylmalonic acid serum levels. Pregnant and lactating vegan or vegetarian women should ensure an adequate intake of vitamin B12 to provide for their developing baby. In people who can absorb vitamin B12, small amounts (in line with the recommended dietary intake) and frequent (daily) doses appear to be more effective than infrequent large doses, including intramuscular injections. Fortification of a wider range of foods products with vitamin B12, particularly foods commonly consumed by vegetarians, is likely to be beneficial, and the feasibility of this should be explored by relevant food authorities.

Meeting the nutrient reference values on a vegetarian diet.

Surveys over the past 10 years have shown that Australians are increasingly consuming more plant-based vegetarian meals. Many studies demonstrate the health benefits of vegetarian diets. As with any type of eating plan, vegetarian diets must be well planned to ensure nutritional needs are being met. This clinical focus project shows that well planned vegetarian diets can meet almost all the nutritional needs of children and adults of all ages. Sample single-day lacto-ovo-vegetarian meal plans were developed to comply with the nutrient reference values - including the increased requirements for iron and zinc at 180% and 150%, respectively, for vegetarians - for both sexes and all age groups set by Australia's National Health and Medical Research Council and the New Zealand Ministry of Health. With the exception of vitamin D, long-chain omega-3 fatty acids and extended iron requirements in pregnancy for vegetarians, the meal plans meet key requirements with respect to energy; protein; carbohydrate; total fat; saturated, poly- and monounsaturated fats; α-linolenic acid; fibre; iron; zinc; calcium; folate; and vitamins A, C, E and B12.

Protein and vegetarian diets.

A vegetarian diet can easily meet human dietary protein requirements as long as energy needs are met and a variety of foods are eaten. Vegetarians should obtain protein from a variety of plant sources, including legumes, soy products, grains, nuts and seeds. Eggs and dairy products also provide protein for those following a lacto-ovo-vegetarian diet. There is no need to consciously combine different plant proteins at each meal as long as a variety of foods are eaten from day to day, because the human body maintains a pool of amino acids which can be used to complement dietary protein. The consumption of plant proteins rather than animal proteins by vegetarians may contribute to their reduced risk of chronic diseases such as diabetes and heart disease.

Glycemic index and glycemic load of carbohydrates in the diabetes diet.

Medical nutrition therapy is the first line of treatment for the prevention and management of type 2 diabetes and plays an essential part in the management of type 1 diabetes. Although traditionally advice was focused on carbohydrate quantification, it is now clear that both the amount and type of carbohydrate are important in predicting an individual's glycemic response to a meal. Diets based on carbohydrate foods that are more slowly digested, absorbed, and metabolized (i.e., low glycemic index [GI] diets) have been associated with a reduced risk of type 2 diabetes and cardiovascular disease, whereas intervention studies have shown improvements in insulin sensitivity and glycated hemoglobin concentrations in people with diabetes following a low GI diet. Research also suggests that low GI diets may assist with weight management through effects on satiety and fuel partitioning. These findings, together with the fact that there are no demonstrated negative effects of a low GI diet, suggest that the GI should be an important consideration in the dietary management and prevention of diabetes.

Dietary management in diabetes.

BACKGROUND: Type 1 diabetes is primarily an autoimmune disease and type 2 diabetes is primarily a metabolic condition. However, medical nutrition therapy is an integral part of management for both types of diabetes to improve glycaemic control and reduce the risk of complications. OBJECTIVE: To outline the principles of dietary management in type 1 and type 2 diabetes and provide strategies to assist in overcoming common difficulties related to diet. DISCUSSION: All people with diabetes should be provided with quality professional education on medical nutrition therapy upon diagnosis, and at regular intervals thereafter. For children and adolescent patients with type 1 diabetes, the challenge is to maintain good glycaemic control while providing adequate energy for growth and development. Modification in dietary advice is required, depending on developmental stage. In type 2 diabetes, the initial challenge is to achieve weight loss of 5-10% body weight, normalise blood glucose and reduce cardiovascular risk factors. Specific strategies include a kilojoule controlled diet with reduced saturated fat, trans fat and sodium; moderate protein; and high in dietary fibre and low glycaemic index carbohydrates. Carbohydrates should be spread evenly throughout the day and matched to medication.

Effect of a low glycemic index compared with a conventional healthy diet on polycystic ovary syndrome.

BACKGROUND: Women with polycystic ovarian syndrome (PCOS) are intrinsically insulin resistant and have a high risk of cardiovascular disease and type 2 diabetes. Weight loss improves risk factors, but the optimal diet composition is unknown. Low-glycemic index (low-GI) diets are recommended without evidence of their clinical effectiveness. OBJECTIVE: We compared changes in insulin sensitivity and clinical outcomes after similar weight losses after consumption of a low-GI diet compared with a conventional healthy diet in women with PCOS. DESIGN: We assigned overweight and obese premenopausal women with PCOS (n = 96) to consume either an ad libitum low-GI diet or a macronutrient-matched healthy diet and followed the women for 12 mo or until they achieved a 7% weight loss. We compared changes in whole-body insulin sensitivity, which we assessed using the insulin sensitivity index derived from the oral-glucose-tolerance test (ISI(OGTT)); glucose tolerance; body composition; plasma lipids; reproductive hormones; health-related quality of life; and menstrual cycle regularity. RESULTS: The attrition rate was high in both groups (49%). Among completers, ISI(OGTT) improved more with the low-GI diet than with the conventional healthy diet (mean +/- SEM: 2.2 +/- 0.7 compared with 0.7 +/- 0.6, respectively; P = 0.03). There was a significant diet-metformin interaction (P = 0.048), with greater improvement in ISI(OGTT) among women prescribed both metformin and the low-GI diet. Compared with women who consumed the conventional healthy diet, more women who consumed the low-GI diet showed improved menstrual cyclicity (95% compared with 63%, respectively; P = 0.03). Among the biochemical measures, only serum fibrinogen concentrations showed significant differences between diets (P < 0.05). CONCLUSION: To the best of our knowledge, this study provides the first objective evidence to justify the use of low-GI diets in the management of PCOS.

Meeting nutritional needs on a vegetarian diet.

A vegetarian is a person who consumes a diet consisting mostly of plant based foods including fruit, vegetables, legumes, nuts, seeds and grains. Some vegetarians also consume eggs and dairy foods. Individuals choose to follow a vegetarian diet for a range of reasons, including animal rights and religion, but two common reasons are the health and environmental benefits of plant based eating.

The optimal diet for women with polycystic ovary syndrome?

An optimal diet is one that not only prevents nutrient deficiencies by providing sufficient nutrients and energy for human growth and reproduction, but that also promotes health and longevity and reduces the risk of diet-related chronic diseases. The composition of the optimal diet for women with polycystic ovary syndrome (PCOS) is not yet known, but such a diet must not only assist short term with weight management, symptoms and fertility, but also specifically target the long-term risks of type 2 diabetes, CVD and certain cancers. With insulin resistance and compensatory hyperinsulinaemia now recognised as a key factor in the pathogenesis of PCOS, it has become clear that reducing insulin levels and improving insulin sensitivity are an essential part of management. Diet plays a significant role in the regulation of blood glucose and insulin levels, yet research into the dietary management of PCOS is lacking and most studies have focused on energy restriction rather than dietary composition per se. On the balance of evidence to date, a diet low in saturated fat and high in fibre from predominantly low-glycaemic-index-carbohydrate foods is recommended. Because PCOS carries significant metabolic risks, more research is clearly needed.