Non-Pharmacological Treatments for Insulin Resistance: Effective Intervention of Plant-Based Diets—A Critical Review

A whole-food, plant-based randomized controlled trial in metastatic breast cancer: weight, cardiometabolic, and hormonal outcomes

PURPOSE

Breast cancer treatment is associated with weight gain, and obesity and its related cardiometabolic and hormonal risk factors have been associated with poorer outcomes. Dietary intervention may address these risk factors, but limited research has been done in the setting of metastatic breast cancer requiring systemic therapy.

METHODS

Women with metastatic breast cancer on stable treatment were randomized 2:1 to an 8-week intervention (n = 21) or control (n = 11). The intervention included weekly assessment visits and an ad libitum whole-food, plant-based (WFPB) diet with provided meals. Cardiometabolic, hormonal, and cancer markers were assessed at baseline, 4 weeks, and 8 weeks.

RESULTS

Within the intervention group, mean weight decreased by 6.6% (p < 0.01) after 8 weeks. Fasting insulin decreased from 16.8 uIU/L to 11.2 uIU/L (p < 0.01), concurrent with significantly reduced insulin resistance. Total cholesterol decreased from 193.6 mg/dL to 159 mg/dL (p < 0.01), and low-density lipoprotein (LDL) cholesterol decreased from 104.6 mg/dL to 82.2 mg/dL (p < 0.01). Total testosterone was unchanged, but free testosterone trended lower within the intervention group (p = 0.08) as sex hormone binding globulin increased from 74.3 nmol/L to 98.2 nmol/L (p < 0.01). There were no significant differences in cancer progression markers at week 8, although mean CA 15-3, CA 27.29, and CEA were lower in the intervention group (p = 0.53, p = 0.23, and p = 0.54, respectively) compared to control, when adjusted for baseline.

CONCLUSION

WFPB dietary changes during treatment for metastatic breast cancer are well tolerated and significantly improve weight, cardiometabolic and hormonal parameters. Longer studies are warranted to assess the durability of changes. Trial registration First registered at Clinicaltrials.gov (NCT03045289) on February 7, 2017.

Plant-Based Food for the Prevention of Type 2 Diabetes: Scoping Review

Type 2 Diabetes Mellitus (T2DM) is a chronic condition with growing worldwide prevalence. Besides genetic factors, a sedentary lifestyle, excess weight, and inadequate eating habits, characterized by an excess intake of refined carbohydrates and ultra-processed foods, are contributing factors for the development of the disease. In this scenario, promoting a plant-based diet, and limiting animal product consumption while increasing the intake of vegetables, concurrently with healthy lifestyle habits, is a promising strategy to prevent T2DM. This scoping review, carried out between 2017 and 2022, aimed to gather evidence substantiating the benefits of a plant-based diet in T2DM prevention, considering different eating patterns, such as vegetarian, vegan, Mediterranean, and DASH diets. Several studies demonstrate a significant reduction in T2DM incidence among individuals adopting plant-based eating patterns or emphasizing healthy plant-based food alongside decreased intake or exclusion of animal-based foods. There are still no robust data regarding plant-based diets and the prevention of diabetes without loss in body weight. Hence, prospective studies in plant-based diets with weight control are needed. Nevertheless, adopting plant-based diets appears to induce significant weight loss, which is crucial in an obesity-endemic context. Thus, embracing plant-based diets, along with healthy habits, emerges as a relevant strategy in obesity and T2DM prevention.

Docosahexaenoic and Eicosapentaenoic Acids Promote the Accumulation of Browning-Related Myokines via Calcium Signaling in Insulin-Resistant Mice

BACKGROUND

Myokines have a prominent effect on improving insulin resistance (IR) by inducing browning of white adipose tissue (WAT). Although docosahexaenoic acids (DHA) and eicosapentaenoic acids (EPA) play roles in improving IR and stimulating browning, whether they mediate myokines directly remains unknown.

OBJECTIVE

This study aims to investigate the effects of DHA and EPA on browning-related myokines under IR and clarify the mechanism via Ca2+ signaling.

METHODS

The expression and secretion levels of myokines in IR mice and IR myotubes were detected after DHA/EPA treatment. The crosstalk between myotubes and adipocytes was evaluated through a method in which IR adipocytes were treated with the culture medium supernatant of myotubes treated with DHA/EPA. The expression of browning markers in the WAT of IR mice and adipocytes was determined. A calcium chelator was used to determine whether DHA and EPA regulate myokine production through a calcium ion-dependent pathway.

RESULTS

In vivo experiments: 3:1 and 1:3 DHA/EPA promoted the mRNA levels of Irisin, IL-6, IL-15, and FGF21 in skeletal muscle, stimulated WAT browning, reduced lipid accumulation; 3:1 DHA/EPA upregulated the serum concentration of Irisin; 1:3 DHA/EPA upregulated the serum concentrations of Irisin, IL-6, and FGF21. In vitro experiments: the levels of Irisin and IL-6 in C2C12 myotubes and their medium supernatant were significantly elevated in the 3:1 and 1:3 groups and the upregulation of browning markers and reduction in fat accumulation were observed in adipocytes treated with the medium supernatant of C2C12 myotubes in the 3:1 and 1:3 groups. However, the above phenomena disappeared when Ca2+ signaling was inhibited.

CONCLUSIONS

Treatment with DHA and EPA at composition ratios of 3:1 and 1:3 induces browning of WAT in IR mice, which is likely related to the promotion of the accumulation of myokines, especially Irisin and IL-6, via Ca2+ signaling.

Exploring Australian News Media Portrayals of Sustainable and Plant-Based Diets

(1) Background: Dietary behaviour transformation is imperative for the attainment of more sustainable food systems, including an increased intake of plant-based foods and lower consumption of red meat and highly processed foods. The influence of news media coverage on public opinion regarding dietary behaviours is significant. Therefore, this study aimed to explore how sustainable/plant-based diets have been portrayed in Australian news media. (2) Methods: The Factiva global news database was used to search news articles published in Australia between 2018 and 2020. Relevant news articles were selected if they included keywords relating to sustainable diets, plant-based diets, and meat alternatives. We used a coding protocol to extract key information, such as date of publication, article topic, and any health, environmental and economic impacts. Then, we performed a framing and thematic analysis of the data. (3) Results: From 357 included articles, more than half of the articles encouraged increasing the intake of plant-based foods (53.5%) and reducing animal-derived food intake (55.2%). Several reasons for such shift from animal protein centric Australian diets were identified throughout the articles such as health benefits (15.4%), environmental impacts (11.2%), animal welfare (4.8%), seasonality and local food intake (5.3%), avoiding overconsumption (4.5%) and food wastage (4.5%). (4) Conclusions: The predominant frame in Australian news coverage about sustainable diets has been about consumption, more plant- and less animal-based products, with little nuance about the complex interplay of diet quality and environment in influencing food choices. Australian news media should broaden its coverage of sustainable diets to include health, environmental, and economic factors to improve public understanding and facilitate informed and sustainable food choices. Further research is needed to enhance comprehension of how the audience perceives media coverage on this topic, which will provide a more thorough understanding.

Insulin Resistance/Diabetes and Schizophrenia: Potential Shared Genetic Factors and Implications for Better Management of Patients with Schizophrenia

Schizophrenia is a complex psychotic disorder with co-occurring conditions, including insulin resistance and type 2 diabetes (T2D). It is well established that T2D and its precursors (i.e., insulin resistance) are more prevalent in patients with schizophrenia who are treated with antipsychotics, as well as in antipsychotic-naïve patients experiencing their first episode of psychosis, compared with the general population. However, the mechanism(s) underlying the increased susceptibility, shared genetics, and possible cause-effect relationship between schizophrenia and T2D remain largely unknown. The objective of this narrative review was to synthesize important studies, including Mendelian randomization (MR) analyses that have integrated genome-wide association studies (GWAS), as well as results from in vitro models, in vivo models, and observational studies of patients with schizophrenia. Both GWAS and MR studies have found that schizophrenia and T2D/insulin resistance share genetic risk factors, and this may mediate a connection between peripheral or brain insulin resistance and T2D with cognition impairment and an increased risk of developing prediabetes and T2D in schizophrenia. Moreover, accumulating evidence supports a causal role for insulin resistance in schizophrenia and emphasizes the importance of a genetic basis for susceptibility to T2D in patients with schizophrenia before they receive psychotic treatment. The present findings and observations may have clinical implications for the development of better strategies to treat patients with schizophrenia, with both pharmacological (i.e., samidorphan, empagliflozin) and/or nonpharmacological (i.e., lifestyle changes) approaches. Additionally, this review may benefit the design of future studies by physicians and clinical investigators.

A Narrative Review on Strategies for the Reversion of Prediabetes to Normoglycemia: Food Pyramid, Physical Activity, and Self-Monitoring Innovative Glucose Devices

In 2019, "Nutrition Therapy for Adults with Diabetes or Prediabetes: A Consensus Report" was published. This consensus report, however, did not provide an easy way to illustrate to subjects with prediabetes (SwPs) how to follow a correct dietary approach. The purpose of this review is to evaluate current evidence on optimum dietary treatment of SwPs and to provide a food pyramid for this population. The pyramid built shows that everyday consumption should consist of: whole-grain bread or potatoes eaten with their skins (for fiber and magnesium) and low glycemic index carbohydrates (GI < 55%) (three portions); fruit and vegetables (5 portions), in particular, green leafy vegetables (for fiber, magnesium, and polyphenols); EVO oil (almost 8 g); nuts (30 g, in particular, pistachios and almonds); three portions of dairy products (milk/yogurt: 300-400 g/day); mineral water (almost 1, 5 L/day for calcium intake); one glass of wine (125 mL); and three cups of coffee. Weekly portions should include fish (four portions), white meat (two portions), protein plant-based food (four portions), eggs (egg portions), and red/processed meats (once/week). At the top of the pyramid, there are two pennants: a green one means that SwPs need some personalized supplementation (if daily requirements cannot be satisfied through diet, vitamin D, omega-3, and vitamin B supplements), and a red one means there are some foods and factors that are banned (simple sugar, refined carbohydrates, and a sedentary lifestyle). Three to four times a week of aerobic and resistance exercises must be performed for 30-40 min. Finally, self-monitoring innovative salivary glucose devices could contribute to the reversion of prediabetes to normoglycemia.

A Whole-Food, Plant-Based Randomized Controlled Trial in Metastatic Breast Cancer: Weight, Cardiometabolic, and Hormonal Outcome

Purpose

Breast cancer treatment is associated with weight gain, and obesity and its related cardiometabolic and hormonal risk factors have been associated with poorer outcomes. Dietary intervention may address these risk factors, but limited research has been done in the setting of metastatic breast cancer requiring systemic therapy.

Methods

Women with metastatic breast cancer on stable treatment were randomized 2:1 to an 8-week intervention (n = 21) or control (n = 11). The intervention included weekly assessment visits and an ad libitum whole food, plant-based (WFPB) diet with provided meals. Cardiometabolic, hormonal, and cancer markers were assessed at baseline, 4 weeks, and 8 weeks.

Results

Within the intervention group, mean weight decreased by 6.6% (p < 0.01) after 8 weeks. Fasting insulin decreased from 16.8 uIU/L to 11.2 uIU/L (p < 0.01), concurrent with significantly reduced insulin resistance. Total cholesterol decreased from 193.6 mg/dL to 159 mg/dL (p < 0.01) and low-density lipoprotein (LDL) cholesterol decreased from 104.6 mg/dL to 82.2 mg/dL (p < 0.01). Total testosterone was unchanged, but free testosterone trended lower within the intervention group (p = 0.08) as sex hormone binding globulin increased from 74.3 nmol/L to 98.2 nmol/L (p < 0.01). There were no significant differences in cancer progression markers at week 8, although mean CA 15 - 3, CA 27.29, and CEA were lower in the intervention group (p = 0.53, p = 0.23, and p = 0.54, respectively) compared to control, when adjusted for baseline.

Conclusion

WFPB dietary changes during treatment for metastatic breast cancer are well tolerated and significantly improve weight and cardiometabolic and hormonal parameters. Longer studies are warranted to assess the durability of changes.

Trial registration

First registered at Clinicaltrials.gov (NCT03045289) on February 7, 2017.

Plant-based dietary patterns and fasting insulin: a cross-sectional study from NHANES 2017-2018

BACKGROUND

Previous studies have created plant-based diet indices to assess the health effects of specific dietary patterns.

OBJECTIVE

To examine the association between the plant-based content of diet and fasting insulin in adults from the NHANES 2017-2018 database.

METHODS

Demographic, dietary, lab and clinical data and fasting insulin were obtained from the NHANES 2017-2018 database. From two 24-h dietary recalls, we created a plant-based diet index (PDI) and a healthy plant-based diet index (hPDI). A high PDI score indicated more plants were consumed versus animal foods. A high hPDI score indicated healthier, plant materials (whole grains, whole fruits, vegetables, legumes, vegetable oils, seeds and nuts) were consumed. The relationships between the natural log of fasting insulin, PDI, and hPDI were analyzed using multiple linear regression adjusting for body mass index (BMI) and alanine aminotransferase (ALT).

RESULTS

Analyses were based on 1,714 participants, 897 women and 817 men with a median age of 52 years. In this sample, 610 (35.6%) were white, 407 (23.8%) were black, 231 (13.5%) were Mexican, 207 (12.1%) were Asian, 157 (9.2%) were other Hispanic, and 102 (6%) were other or mixed race. Median fasting insulin was 9.74 μU/mL (IQR: 6.2, 15.56). For every 1 unit increase in PDI, the natural log of fasting insulin decreased 0.0068 ± 0.003 μU/mL (CI: -0.00097, -0.013) (p = 0.02). After adjusting for BMI and ALT, the PDI did not significantly predict fasting insulin as the association was not robust due to multicollinearity. The hPDI was inversely and significantly associated with the natural log of fasting insulin (-0.0027 ± 0.00134, CI: -0.000087, -0.0053) (p = 0.043) in a multivariable model including BMI and ALT.

CONCLUSION

A healthy plant-based diet is associated with a decrease in fasting insulin levels. Healthfulness of the diet is an important factor when considering the benefit of a plant-based diet.

Relationship between Abdominal Volume Index and Body Adiposity Index and Scales of Insulin Resistance and Metabolic Syndrome

Introduction, objectives: Obesity is a global health problem with a great negative impact on health. Among the pathologies caused by obesity are insulin resistance and metabolic syndrome, which constitute an increasingly common health problem in both developed and developing countries. The aim of this study was to examine the relationship between two scales that assess obesity-based on hip circumference-and metabolic syndrome (MetS) and insulin resistance risk scales as predictors of these alterations.

MATERIALS, METHODS

A descriptive, cross-sectional study was carried out on 193,462 workers from different Spanish regions and work groups between January 2019 and September 2021. Abdominal volume index (AVI) and body adiposity index (BAI) were evaluated to assess obesity and its association with insulin resistance using three risk scales (TyG index, Triglycerides/HDL, and METS-IR), while their association with metabolic syndrome was determined using the NCEP ATP III, IDF, and JIS models.

RESULTS

The results of the ROC curves to determine the predictive value of BAI and AVI in relation to the three criteria evaluated to calculate MetS in all instances presented a higher area under the curve (AUC) for AVI. The high values of AVI stand out for predicting MetS when applying the IDF criteria. The cut-off point in women was 13.70 with a Youden index of 0.802, whereas in men, the cut-off point was set at 17.59 with a Youden index of 0.672. Regarding the relationship of BAI and AVI with insulin resistance risk scales for both sexes, the AUC only revealed high values when using the METS-IR formula for both AVI and BAI. The AVI cut-off points to predict high values of insulin resistance risk scales in women were established at 13.12 with a Youden index of 0.722. In men, the cut-off point was 17.59, with a Youden index of 0.626. The BAI cut-off points in women were set at 33.88 with a Youden index of 0.748. In men, the cut-off point was 27.91, with a Youden index of 0.598.

CONCLUSIONS

AVI demonstrated its value as a predictor of metabolic syndrome while exclusively applying the IDF criteria. AVI and BAI demonstrated their value as predictors of high values of insulin resistance risk scales only in the case of METS-IR. This predictive value is also higher in women.

Plant-Based Nutrition: Exploring Health Benefits for Atherosclerosis, Chronic Diseases, and Metabolic Syndrome-A Comprehensive Review

Atherosclerosis, chronic non-communicable diseases, and metabolic syndrome are highly interconnected and collectively contribute to global health concerns that reduce life expectancy and quality of life. These conditions arise from multiple risk factors, including inflammation, insulin resistance, impaired blood lipid profile, endothelial dysfunction, and increased cardiovascular risk. Adopting a plant-based diet has gained popularity as a viable alternative to promote health and mitigate the incidence of, and risk factors associated with, these three health conditions. Understanding the potential benefits of a plant-based diet for human health is crucial, particularly in the face of the rising prevalence of chronic diseases like diabetes, hypertension, dyslipidemia, atherosclerosis, and cancer. Thus, this review focused on the plausible advantages of consuming a type of food pattern for the prevention and/or treatment of chronic diseases, emphasizing the dietary aspects that contribute to these conditions and the evidence supporting the benefits of a plant-based diet for human health. To facilitate a more in-depth analysis, we present separate evidence for each of these three concepts, acknowledging their intrinsic connection while providing a specific focus on each one. This review underscores the potential of a plant-based diet to target the underlying causes of these chronic diseases and enhance health outcomes for individuals and populations.

The Effect of a Vegan Diet on the Cardiovascular System

The vegan diet, often known as a plant-rich diet, consists primarily of plant-based meals. This dietary approach may be beneficial to one’s health and the environment and is valuable to the immune system. Plants provide vitamins, minerals, phytochemicals, and antioxidants, components that promote cell survival and immune function, allowing its defensive mechanisms to work effectively. The term “vegan diet” comprises a range of eating patterns that prioritize nutrient-rich foods such as fruits and vegetables, legumes, whole grains, nuts, and seeds. In comparison to omnivorous diets, which are often lower in such products, the vegan diet has been favorably connected with changes in cardiovascular disease (CVD) risk markers such as reduced body mass index (BMI) values, total serum cholesterol, serum glucose, inflammation, and blood pressure. Reduced intake of low-density lipoprotein (LDL), saturated fat, processed meat, and greater consumption of fiber and phytonutrients may improve cardiovascular health. However, vegans have much smaller amounts of nutrients such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), selenium, zinc, iodine, and vitamin B12, compared to non-vegans, which may lead to detrimental cardiovascular effects. This review aims to present the effect of plant-based diets (PBDs), specifically vegan diets, on the cardiovascular system.

Diet's Role in Modifying Risk of Alzheimer's Disease: History and Present Understanding

Diet is an important nonpharmacological risk-modifying factor for Alzheimer's disease (AD). The approaches used here to assess diet's role in the risk of AD include multi-country ecological studies, prospective and cross-sectional observational studies, and laboratory studies. Ecological studies have identified fat, meat, and obesity from high-energy diets as important risk factors for AD and reported that AD rates peak about 15-20 years after national dietary changes. Observational studies have compared the Western dietary pattern with those of the Dietary Approaches to Stop Hypertension (DASH), Mediterranean (MedDi), and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diets. Those studies identified AD risk factors including higher consumption of saturated and total fats, meat, and ultraprocessed foods and a lower risk of AD with higher consumption of fruits, legumes, nuts, omega-3 fatty acids, vegetables, and whole grains. Diet-induced factors associated with a significant risk of AD include inflammation, insulin resistance, oxidative stress, elevated homocysteine, dietary advanced glycation end products, and trimethylamine N-oxide. The molecular mechanisms by which dietary bioactive components and specific foods affect risk of AD are discussed. Given most countries' entrenched food supply systems, the upward trends of AD rates would be hard to reverse. However, for people willing and able, a low-animal product diet with plenty of anti-inflammatory, low-glycemic load foods may be helpful.

Healthy plant-based diets improve dyslipidemias, insulin resistance, and inflammation in metabolic syndrome. A narrative review

Plant-based diets (PBDs) have become very popular in recent years and have been identified as a dietary strategy associated with protection against chronic disease. However, the classifications of PBDs vary depending on the type of diet. Some PBDs have been recognized as healthful for their high content of vitamins, minerals, antioxidants, and fiber, or unhealthful if they are high in simple sugars and saturated fat. Depending on this classification, the type of PBD impacts its protective effects against disease dramatically. Metabolic syndrome (MetS), characterized by the presence of high plasma triglycerides and low HDL cholesterol, impaired glucose metabolism, elevated blood pressure, and increased concentrations of inflammatory biomarkers, also increases the risk for heart disease and diabetes. Thus, healthful plant-based diets could be considered favorable for individuals having MetS. The different types of plant-based diets (vegan, lacto-vegetarian, lacto-ovo-vegetarian, or pescatarian) are discussed with a focus on specific effects of dietary components in maintaining a healthy weight, protecting against dyslipidemias, insulin resistance, hypertension, and low-grade inflammation.

Plant-based diet for obesity treatment

Obesity rates continue to rise, resulting in a global epidemic that shows no sign of slowing down. Our understanding of this complex disease is also constantly evolving, requiring healthcare providers to stay up to date with best practices. The application of plant-based diets (PBDs) may hold the key to a successful weight-control strategy. PBD refers to any dietary pattern that emphasizes the consumption of plant foods while excluding the consumption of most or all animal products. The purpose of this mini-review is to report on the application of PBDs as a potential treatment for obesity. PBDs have also been shown to be beneficial in the treatment of other non-communicable diseases, such as the prevention and treatment of type 2 diabetes. Many of the reported RCTs were of short duration. Longer-term studies, as well as studies focusing on strict adherence to the PBD regime, are needed. PBD is a beneficial approach to improving health, particularly in obese patients. Benefits include weight loss, improved cardiovascular health, lower blood pressure, and improved glucose metabolism.