Does diet quality matter? A secondary analysis of a randomized clinical trial

This secondary analysis assessed the association of a plant-based index (PDI), healthful (hPDI), and unhealthful (uPDI), with weight loss in overweight adults. Participants (n = 244) were randomly assigned to a vegan (n = 122) or control group (n = 122) for 16 weeks. Three-day dietary records were analyzed and PDI indices were calculated. A repeated measure ANOVA was used for statistical analysis. All three scores increased in the vegan group; the effect sizes were: PDI +10.6 (95% CI +8.6 to +12.6; p < 0.001); hPDI +10.9 (95% CI +8.4 to +13.4; p < 0.001); and uPDI +5.4 (95% CI +3.4 to +7.4; p < 0.001). The change in all three scores significantly correlated with change in body weight: PDI (r = -0.40; p < 0.001); hPDI (r = -0.37; p < 0.001); and uPDI (r = -0.21; p = 0.002). These findings suggest that minimizing the consumption of animal products and oil may be an effective weight loss strategy in overweight adults. ClinicalTrials.gov number, NCT02939638.

A dietary intervention for postmenopausal hot flashes: A potential role of gut microbiome. An exploratory analysis

OBJECTIVE

This study examined the role of gut microbiome changes in mediating the effects of a dietary intervention on the frequency and severity of postmenopausal vasomotor symptoms METHODS: Postmenopausal women (n = 84) reporting ≥2 moderate-to-severe hot flashes daily were randomly assigned, in 2 successive cohorts, to an intervention including a low-fat, vegan diet and cooked soybeans (½ cup [86 g] daily) or to stay on their usual diet. Over a 12-week period, frequency and severity of hot flashes were recorded with a mobile application. In a subset of 11 women, gut microbiome was analyzed at baseline and after 12 weeks of the dietary intervention (low-fat vegan diet with soybeans), using deep shotgun metagenomic sequencing. Differences in the microbiome between baseline and 12 weeks were assessed by comparing alpha diversity with Wilcoxon signed rank tests, beta diversity with permanovaFL, and taxon abundance with Wilcoxon signed rank tests. Pearson correlations were used to assess the association between changes in hot flashes and gut bacteria.

RESULTS

In the subset for which microbiome testing was done, total hot flashes decreased by 95 % during the dietary intervention (p = 0.007); severe hot flashes disappeared (from 0.6 to 0.0/day; p = 0.06); and moderate-to-severe hot flashes decreased by 96 % (p = 0.01). Daytime and nighttime hot flashes were reduced by 96 % (p = 0.01) and 94 % (p = 0.004), respectively. Alpha and beta diversity did not significantly differ in the intervention group between baseline and 12 weeks. Two families (Enterobacteriaceae and Veillonellaceae), 5 genera (Erysipelatoclostridium, Fusicatenibacter, Holdemanella, Intestinimonas, and Porphyromonas), and 6 species (Clostridium asparagiforme, Clostridium innocuum, Bacteroides thetaiotaomicron, Fusicatenibacter saccharivorans, Intestinimonas butyriciproducens, Prevotella corporis, and Streptococcus sp.) were differentially abundant, but after correction for multiple comparisons, these differences were no longer significant. Changes in the relative abundance of Porphyromonas and Prevotella corporis were associated with the reduction in severe day hot flashes both unadjusted (r = 0.61; p = 0.047; and r = 0.69; p = 0.02), respectively), and after adjustment for changes in body mass index (r = 0.63; p = 0.049; and r = 0.73; p = 0.02), respectively). Changes in relative abundance of Clostridium asparagiforme were associated with the reduction in total severe hot flashes (r = 0.69; p = 0.019) and severe night hot flashes (r = 0.82; p = 0.002) and the latter association remained significant after adjustment for changes in body mass index (r = 0.75; p = 0.01).

CONCLUSIONS

This exploratory analysis revealed potential associations between changes in vasomotor symptoms in response to a diet change and changes in the gut microbiome. Larger randomized clinical trials are needed to investigate these findings.

Vegan Diet and Food Costs Among Adults With Overweight: A Secondary Analysis of a Randomized Clinical Trial

This secondary analysis of a randomized clinical trial investigates the effects of a vegan diet on total food costs per day.

Dietary advanced glycation products and their associations with insulin sensitivity and body weight: A 16-week randomized clinical trial

Background

Evidence suggests that changes in advanced glycation end-products (AGEs) may influence body weight. Previous studies have focused on cooking methods as the primary way how to reduce the dietary AGEs but little is known about the effects of a change in diet composition.

Objective

The aim of this study was to assess the effects of a low-fat plant-based diet on dietary AGEs and test the association with body weight, body composition, and insulin sensitivity.

Methods

Participants who were overweight (n = 244) were randomly assigned to an intervention (low-fat plant-based) (n = 122) or control group (n = 122) for 16 weeks. Before and after the intervention period, body composition was measured by dual X-ray absorptiometry. Insulin sensitivity was assessed with the predicted insulin sensitivity index (PREDIM). Three-day diet records were analyzed using the Nutrition Data System for Research software and dietary AGEs were estimated, using a database. Repeated measure ANOVA was used for statistical analysis.

Results

Dietary AGEs decreased in the intervention group by 8768 ku/day on average (95% -9611 to -7925; p < 0.001), compared with the control group (-1608; 95% CI -2709 to -506; p = 0.005; treatment effect -7161 ku/day [95% CI -8540 to -5781]; Gxt, p < 0.001). Body weight decreased by 6.4 kg in the intervention group, compared with 0.5 kg in the control group (treatment effect -5.9 kg [95% CI -6.8 to -5.0]; Gxt, p < 0.001), largely due to a reduction in fat mass, notably visceral fat. PREDIM increased in the intervention group (treatment effect +0.9 [95% CI + 0.5 to +1.2]; p < 0.001). Changes in dietary AGEs correlated with changes in body weight (r = +0.41; p < 0.001), fat mass (r = +0.38; p < 0.001), visceral fat (r = +0.23; p < 0.001), and PREDIM (r = -0.28; p < 0.001), and remained significant even after adjustment for changes in energy intake (r = +0.35; p < 0.001 for body weight; r = +0.34; p < 0.001 for fat mass; r = +0.15; p = 0.03 for visceral fat; and r = -0.24; p < 0.001 for PREDIM).

Conclusions

Dietary AGEs decreased on a low-fat plant-based diet, and this decrease was associated with changes in body weight, body composition, and insulin sensitivity, independent of energy intake. These findings demonstrate positive effects of qualitative dietary changes on dietary AGEs and cardiometabolic outcomes.

Clinical Trial Registry Number

NCT02939638.

Dietary advanced glycation end-products and postmenopausal hot flashes: A post-hoc analysis of a 12-week randomized clinical trial

OBJECTIVE

Postmenopausal hot flashes are associated with an increased risk of cardiovascular disease and diabetes. Because dietary advanced glycation end-products (AGEs) may act as endocrine disruptors, this study examined the potential association of modifications to the intake of dietary AGEs with the frequency and severity of postmenopausal hot flashes.

METHODS

Postmenopausal women (n = 84) reporting ≥2 moderate-to-severe hot flashes daily were randomly assigned to either the intervention group or the control group. The former were asked to follow a low-fat, vegan diet, including cooked soybeans (1/2 cup [86 g]/day) for 12 weeks, and the latter continued their usual diets for 12 weeks. Frequency and severity of hot flashes were recorded with a mobile application. Three-day diet records were analyzed using the Nutrition Data System for Research software and dietary AGEs were estimated, using a database. Seventy-one participants completed the whole study and 63 provided complete hot flash and dietary data for the AGEs analysis (n = 31 in the intervention and n = 24 in the control group). Pearson correlations were used to assess the association between changes in hot flashes and dietary AGEs.

RESULTS

Dietary AGEs decreased in the intervention group by 73 %, that is by 5509 ku/day on average (95 % -7009 to -4009; p < 0.001), compared with the control group (+458; 95 % CI -835 to +1751; p = 0.47; treatment effect -5968 ku/day [95 % CI -7945 to -3991]; Gxt, p < 0.001). Severe hot flashes decreased by 92 % (p < 0.001) and moderate-to-severe hot flashes decreased by 88 % in the intervention group (p < 0.001). Changes in dietary AGEs correlated with changes in severe (r = +0.39; p = 0.002) and moderate hot flashes (r = +0.34; p = 0.009) and remained significant after adjustment for changes in energy intake (r = +0.45; p < 0.001; and r = +0.37; p = 0.004, respectively) and changes in body mass index (r = +0.37; p = 0.004; and r = +0.27; p = 0.04, respectively). The reduction in dietary AGEs required to achieve a predicted reduction in hot flashes by 1/day was 6933 ku/day for severe and 4366 ku/day for moderate-to-severe hot flashes.

CONCLUSIONS

The reduction in dietary AGEs with a low-fat plant-based diet was associated with a significant reduction in the frequency of severe and moderate-to-severe postmenopausal hot flashes, independent of changes in energy intake and weight loss. Plant-based diets could be used not only to alleviate vasomotor symptoms in postmenopausal women, but also to reduce other health risks associated with AGEs.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04587154.

Nutrition in the prevention and treatment of endometriosis: A review

Endometriosis is characterized by the presence of endometrial tissues outside the uterine lining, typically on the external surface of the uterus, the ovaries, fallopian tubes, abdominal wall, or intestines. The prevalence of endometriosis in North America, Australia, and Europe is ~1-5% in women of reproductive age. Treatment options for endometriosis are limited. While over-the-counter medications may be used to reduce acute pain, hormonal treatments are common and may interfere with fertility. In more severe cases, laparoscopic excision procedures and even hysterectomies are used to treat the pain associated with endometriosis. Nutritional interventions may be helpful in the prevention and treatment of endometriosis and associated pain. Reducing dietary fat and increasing dietary fiber have been shown to reduce circulating estrogen concentrations, suggesting a potential benefit for individuals with endometriosis, as it is an estrogen-dependent disease. Meat consumption is associated with greater risk of developing endometriosis. Anti-inflammatory properties of plant-based diets may benefit women with endometriosis. Additionally, seaweed holds estrogen-modulating properties that have benefitted postmenopausal women and offers potential to reduce estradiol concentrations in pre-menopausal women. Furthermore, consumption of vitamin D has been shown to reduce endometrial pain via increased antioxidant capacity and supplementation with vitamins C and E significantly reduced endometriosis symptoms, compared with placebo. More randomized clinical trials are needed to elucidate the role of diet in endometriosis.

Controversial Dietary Patterns: A High Yield Primer for Clinicians

In cardiology clinic visits, the discussion of optimal dietary patterns for prevention and management of cardiovascular disease is usually very limited. Herein, we explore the benefits and risks of various dietary patterns, including intermittent fasting, low carbohydrate, Paleolithic, whole food plant-based diet, and Mediterranean dietary patterns within the context of cardiovascular disease to empower clinicians with the evidence and information they need to maximally benefit their patients.

The Role of Nutrition in COVID-19: Taking a Lesson from the 1918 H1N1 Pandemic

In looking for solutions to the COVID-19 pandemic, important lessons come from the H1N1 influenza pandemic of 1918-1919. During the H1N1 influenza pandemic, the soldiers had better outcomes than the civilian populations, but the best outcomes were reported by a Seventh-day Adventist seminary, where a plant-based diet was provided. The diet has been described as including grains, fruits, nuts, and vegetables. A few clinical trials have also assessed the role of nutrition in COVID-19. One study with almost six hundred thousand participants showed that those with a high consumption of fruits and vegetables had a reduced risk of COVID-19 of any severity by 9% and a reduced risk of severe COVID-19 by 41%. Another study in healthcare workers who were frequently exposed to COVID-19 in their clinical practice has demonstrated that those who reported being on a plant-based diet had a 73% lower risk of moderate-to-severe COVID-19. Based on the lessons from 1918 and the recent nutrition research in COVID-19, it seems plausible that a healthful plant-based diet may be a powerful tool to decrease the risk of severe COVID-19 and should be promoted as one of the public health safety measures.

A Randomized, Crossover Trial of a Nutritional Intervention for Rheumatoid Arthritis

To investigate the effects of a dietary intervention on arthritis pain and disease severity, 44 adults previously diagnosed with rheumatoid arthritis were randomly assigned to a Diet phase (vegan diet for 4 weeks, elimination of additional foods for 3 weeks, and then reintroduction of the eliminated foods individually over 9 weeks) or a Supplement (placebo) phase for 16 weeks. After a 4-week washout, they then switched to the opposite phase. The Disease Activity Score-28 (DAS28) decreased from 4.5 to 2.5 (P < .001) in the Diet phase and from 3.2 to 2.9 (P = .41) in the Supplement phase (between-group P = .01). The mean number of swollen joints decreased from 7.0 to 3.3 in the Diet phase (P = .03) and increased from 4.7 to 5 in the Supplement phase (P = .63; between-group P = .047).

In a subanalysis excluding individuals who increased medications during the study, DAS28 decreased 1.9 points in the Diet phase (P = .003) and .4 points in the Supplement phase (P = .27; between-group P = .04). In a further subanalysis limited to participants making no medication changes, DAS28 decreased 1.5 points in the Diet phase (P = .009) and .3 points in the Supplement phase (P = .40, between-group P = .11). We conclude that the dietary intervention was associated with symptomatic improvements. TRIAL REGISTRATION: Clinicaltrials.gov NCT01544101, NCT01700881, NCT03417648, and NCT03580681

Universal Meals: A Novel Program to Provide Healthful Nutrition to Diverse Communities

Healthcare professionals recommending dietary changes to patients often find that institutional settings—businesses, universities, long-term care facilities, correctional institutions, among others—may not provide the healthful foods that healthcare professionals recommend. Moreover, such institutions encounter an increasing diversity of dietary restrictions, based on allergies, intolerances, religious mandates, or other reasons, that may be challenging to satisfy. To address these issues, experts in health, dietetics, culinary arts, religion, and ethics developed a simple set of guidelines that aim to meet the widest possible range of dietary needs. Three culinary teams then used these guidelines to create “Universal Meals”—simple recipes that were then adapted to larger production sizes for institutional use. The healthfulness of representative sets of meals drawn from these recipes was assessed using the Alternative Healthy Eating Index-2010 and found to be superior to that of a meal pattern based on National Health and Nutrition Examination Survey data.

Trending Nutrition Controversies #3: Top Controversies in 2021

Each year, patients are bombarded with diverging and even contradictory reports concerning the impact of certain additives, foods, and nutrients on cardiovascular health and its risk factors. Accordingly, this third review of nutrition controversies examines the impact of artificial sweeteners, cacao, soy, plant-based meats, nitrates, and meats from grass compared to grain-fed animals on cardiovascular and other health outcomes with the goal of optimizing clinician-led diet counseling.

Nutrition for Hospital Workers During a Crisis: Effect of a Plant-Based Dietary Intervention on Cardiometabolic Outcomes and Quality of Life in Healthcare Employees During the COVID-19 Pandemic

The study tested the effects of a vegan diet on cardiometabolic outcomes and quality of life among healthcare employees during the COVID-19 pandemic. Overweight hospital employees were enrolled and randomly assigned (in a 1:1 ratio) to an intervention group, which was asked to follow a low-fat vegan diet, or a control group, asked to make no diet changes. However, due to COVID-19 disruptions, all participants remained on their usual diets from March to June (12 weeks), creating a de facto control period, and all (n = 12) started the vegan diet with online classes in June, which continued for 12 weeks. Nine participants completed all final assessments. A crossover ANOVA was used for statistical analysis of differences in cardiovascular health during the control period and during the intervention. Despite the ongoing crisis, body weight decreased (treatment effect −5.7 kg [95% CI −9.7 to −1.7]; P = .01); fasting plasma glucose decreased (−11.4 mg/dL [95% CI −18.8 to −4.1]; P = .007); total and LDL-cholesterol decreased (−30.7 mg/dL [95% CI −53.8 to −7.5]; P = .02; and −24.6 mg/dL [−44.8 to −4.3]; P = .02, respectively); diastolic blood pressure decreased (−8.5 mm Hg [95% CI −16.3 to −.7]; P = .03); and quality of life increased (P = .005) during the intervention period, compared with the control period. A vegan diet improved cardiometabolic outcomes and quality of life in healthcare workers at the height of the COVID-19 pandemic.

Ketogenic Diets and Chronic Disease: Weighing the Benefits Against the Risks

Very-low-carbohydrate ketogenic diets have been long been used to reduce seizure frequency and more recently have been promoted for a variety of health conditions, including obesity, diabetes, and liver disease. Ketogenic diets may provide short-term improvement and aid in symptom management for some chronic diseases. Such diets affect diet quality, typically increasing intake of foods linked to chronic disease risk and decreasing intake of foods found to be protective in epidemiological studies. This review examines the effects of ketogenic diets on common chronic diseases, as well as their impact on diet quality and possible risks associated with their use. Given often-temporary improvements, unfavorable effects on dietary intake, and inadequate data demonstrating long-term safety, for most individuals, the risks of ketogenic diets may outweigh the benefits.

The Women's Study for the Alleviation of Vasomotor Symptoms (WAVS): a randomized, controlled trial of a plant-based diet and whole soybeans for postmenopausal women

OBJECTIVE

This study aimed to assess the effects of the combination of a low-fat plant-based diet and soybeans on the frequency and severity of menopausal hot flashes.

METHODS

Postmenopausal women (n = 38) reporting two or more hot flashes/day were randomly assigned to a low-fat, vegan diet, including ½ cup (86 g) of cooked soybeans daily, or to no diet changes for 12 weeks. Frequency and severity of hot flashes were recorded using a mobile application, and vasomotor, psychosocial, physical, and sexual symptoms were assessed using the Menopause-Specific Quality of Life Questionnaire. Significance was assessed using t-tests (continuous outcomes) and chi-squared/McNemar tests (binary outcomes).

RESULTS

Total hot flashes decreased 79% in the intervention group (P < 0.001) and 49% in the control group (P = 0.002; between-group P = 0.01). Moderate-to-severe hot flashes decreased 84% in the intervention group (P < 0.001) and 42% in the control group P = 0.009; between-group P = 0.01). From 0 to 12 weeks, 59% (10/17) of intervention-group participants reported becoming free of moderate and severe hot flashes (P = 0.002). There was no change in this variable in the control group (between-group P < 0.001). The Menopause-Specific Quality of Life Questionnaire revealed significantly greater reductions in the intervention group in vasomotor (P < 0.0001), psychosocial (P = 0.04), physical (P < 0.002), and sexual (P = 0.01) domains.

CONCLUSIONS

The combination of a low-fat, vegan diet and whole soybeans was associated with reduced frequency and severity of hot flashes and improved quality of life in vasomotor, psychosocial, physical, and sexual domains in postmenopausal women. During the 12-week study period, the majority of intervention-group participants became free of moderate-to-severe hot flashes.

Perspective: Plant-Based Eating Pattern for Type 2 Diabetes Prevention and Treatment: Efficacy, Mechanisms, and Practical Considerations

A plant-based eating pattern is associated with a reduced risk of developing type 2 diabetes and is highly effective in its treatment. Diets that emphasize whole grains, vegetables, fruits, and legumes and exclude animal products improve blood glucose concentrations, body weight, plasma lipid concentrations, and blood pressure and play an important role in reducing the risk of cardiovascular and microvascular complications. This article reviews scientific evidence on the effects of plant-based diets for the prevention and treatment of type 2 diabetes. The mechanisms by which plant-based diets improve body weight, insulin sensitivity, and β-cell function are described. Practical considerations including education, nutrition adequacy, and adjusting medications will enhance the success of patients who have diabetes.

A plant-based diet in overweight adults in a 16-week randomized clinical trial: The role of dietary acid load

BACKGROUND

Evidence suggests that changes in dietary acid load may influence body weight, body composition, and insulin sensitivity.

METHODS

Participants (n = 244) were randomly assigned to an intervention (vegan) (n = 122) or control group (n = 122) for 16 weeks. Before and after the intervention period, body composition was measured by dual X-ray absorptiometry. Insulin resistance was assessed with the Homeostasis Model Assessment (HOMA-IR) index and predicted insulin sensitivity index (PREDIM). Repeated measure ANOVA was used for statistical analysis.

RESULTS

Potential Renal Acid Load (PRAL) and Net Endogenous Acid Production (NEAP) decreased significantly in the vegan group with no change in the control group (treatment effect -24.7 mEq/day [95% CI -30.2 to -19.2]; p < 0.001; and -23.8 mEq/day [95% CI -29.6 to -18.0]; p < 0.001, respectively). Body weight decreased by 6.4 kg in the vegan group, compared with 0.5 kg in the control group (treatment effect -5.9 kg [95% CI -6.8 to -5.0]; Gxt, p < 0.001), largely due to a reduction in fat mass and visceral fat. HOMA-IR index decreased and PREDIM increased in the vegan group. After adjustment for energy intake, changes in PRAL and NEAP correlated positively with changes in body weight (r = +0.37; p < 0.001; and r = +0.37; p < 0.001, respectively), fat mass (r = +0.32; p < 0.001; and r = +0.32; p < 0.001, respectively), visceral fat (r = +0.19; p = 0.006; and r = +0.15; p = 0.03, respectively), and HOMA (r = +0.17; p = 0.02; and r = +0.20; p = 0.006, respectively), and negatively with changes in PREDIM (r = -0.22; p = 0.002; and r = -0.27; p < 0.001, respectively).

CONCLUSION

Dietary acid load as part of a plant-based diet was associated with changes in body weight, body composition, and insulin sensitivity, independent of energy intake. Mechanistic explanations suggest that the relationship may be causal.

TRIAL REGISTRATION

ClinicalTrials.gov number, NCT03698955.

The role of nutrition in asthma prevention and treatment

Asthma is a chronic respiratory condition characterized by airway inflammation and hyperreactivity. Prevalence has continued to rise in recent decades as Western dietary patterns have become more pervasive. Evidence suggests that diets emphasizing the consumption of plant-based foods might protect against asthma development and improve asthma symptoms through their effects on systemic inflammation, oxidation, and microbial composition. Additionally, increased fruit and vegetable intake, reduced animal product consumption, and weight management might mediate cytokine release, free radical damage, and immune responses involved in the development and course of asthma. The specific aim of this review paper is to examine the current literature on the associations between dietary factors and asthma risk and control in children and adults. Clinical trials examining the mechanism(s) by which dietary factors influence asthma outcomes are necessary to identify the potential use of nutritional therapy in the prevention and management of asthma.

A Mediterranean Diet and Low-Fat Vegan Diet to Improve Body Weight and Cardiometabolic Risk Factors: A Randomized, Cross-over Trial

Objective: Evidence suggests that both Mediterranean and vegan diets improve body weight and cardiometabolic risk factors, but their relative efficacy has not been compared in a randomized trial.Methods: In a randomized crossover trial, 62 overweight adults were randomly assigned to a Mediterranean or vegan diet for a 16-week period. Body weight, plasma lipids, blood pressure, and body composition (dual X-ray absorptiometry) were measured. Secondary measures included insulin resistance (Homeostasis Model Assessment, HOMA-IR), oral glucose insulin sensitivity (OGIS), and predicted insulin sensitivity (PREDIM) indices. Thereafter, participants were asked to return to their baseline diets for 4 weeks, after which they began the opposite diet for 16 weeks. The same parameters were measured before and after this 2^nd 16-week period.Results: Overall net weight changes were 0.0 (Mediterranean) and -6.0 kg (vegan), (treatment effect -6.0 kg [95% CI -7.5 to -4.5]; p < 0.001). HOMA-IR decreased and OGIS increased on the vegan diet with no significant change on the Mediterranean diet (treatment effect -0.7 [95% CI, -1.8 to +0.4]; p = 0.21; and +35.8 mL/min/m² [95% CI, +13.2 to +58.3]; p = 0.003, respectively). PREDIM did not change significantly in either group. Among participants with no medication changes, total and LDL-cholesterol decreased 18.7 mg/dL (0.5 mmol/L) and 15.3 mg/dL (0.4 mmol/L), respectively, on the vegan diet, compared with no significant change on the Mediterranean diet (treatment effect -15.6 [-24.6 to -6.6]; p = 0.001 and -14.8 [-23.5 to -6.2]; p = 0.001, respectively); systolic and diastolic blood pressure decreased 9.3 and 7.3 mmHg on the Mediterranean diet, compared with 3.4 and 4.1 mmHg on the vegan diet (treatment effect +5.9 [95% CI +1.0 to +10.9]; p = 0.02; and +1.8 [95% CI -4.6 to +8.1]; p = 0.58, respectively).Conclusions: A low-fat vegan diet improved body weight, lipid concentrations, and insulin sensitivity, both from baseline and compared with a Mediterranean diet. Blood pressure decreased on both diets, more on the Mediterranean diet.Clinical trial registration: ClinicalTrials.gov number, NCT03698955 https://clinicaltrials.gov/ct2/show/NCT03698955?term=NCT03698955&draw=2&rank=1.

Blood Type Is Not Associated with Changes in Cardiometabolic Outcomes in Response to a Plant-Based Dietary Intervention

BACKGROUND

Risk of cardiovascular disease is lower in individuals with blood type O and increased in individuals with blood type A, compared with those in other blood groups. However, little evidence is available regarding whether individuals with different blood types benefit from different diet recommendations.

OBJECTIVE

As part of a larger intervention trial using a low-fat vegan diet, this study ascertained whether changes in cardiometabolic outcomes were associated with ABO blood type.

DESIGN

A secondary analysis among intervention-group participants in a 16-week randomized clinical trial.

PARTICIPANTS/SETTING

In a larger study of overweight individuals randomly assigned to follow a low-fat vegan diet or to make no diet changes for 16 weeks, ABO blood typing was conducted on 68 intervention-group participants.

INTERVENTION

Intervention-group participants were asked to follow a low-fat vegan diet and attend weekly educational classes to aid in diet adherence.

MAIN OUTCOME MEASURES

Body weight, fat mass, visceral fat volume, blood lipid levels, fasting plasma glucose levels, and glycated hemoglobin concentrations.

STATISTICAL ANALYSES PERFORMED

Student t tests compared participants with blood type A to all other participants, and individuals with blood type O to all other participants.

RESULTS

There were no significant differences in any outcome between individuals of blood type A and all other participants, or between individuals of blood type O and all other participants. Mean body weight change was -5.7 kg for blood type A participants and -7.0 kg for all other participants (P = 0.09), and was -7.1 kg for type O participants and -6.2 kg for all other participants (P = 0.33). Mean total cholesterol decreased 17.2 mg/dL in the type A group and 18.3 mg/dL for all other participants (P = 0.90), and decreased 17.4 mg/dL among type O participants and 18.4 mg/dL for all other participants (P = 0.89).

CONCLUSIONS

Blood type was not associated with the effects of a plant-based diet on body weight, body fat, plasma lipid concentrations, or glycemic control.

Effect of a Low-Fat Vegan Diet on Body Weight, Insulin Sensitivity, Postprandial Metabolism, and Intramyocellular and Hepatocellular Lipid Levels in Overweight Adults: A Randomized Clinical Trial

IMPORTANCE

Excess body weight and insulin resistance lead to type 2 diabetes and other major health problems. There is an urgent need for dietary interventions to address these conditions.

OBJECTIVE

To measure the effects of a low-fat vegan diet on body weight, insulin resistance, postprandial metabolism, and intramyocellular and hepatocellular lipid levels in overweight adults.

DESIGN, SETTING, AND PARTICIPANTS

This 16-week randomized clinical trial was conducted between January 2017 and February 2019 in Washington, DC. Of 3115 people who responded to flyers in medical offices and newspaper and radio advertisements, 244 met the participation criteria (age 25 to 75 years; body mass index of 28 to 40) after having been screened by telephone.

INTERVENTIONS

Participants were randomized in a 1:1 ratio. The intervention group (n = 122) was asked to follow a low-fat vegan diet and the control group (n = 122) to make no diet changes for 16 weeks.

MAIN OUTCOMES AND MEASURES

At weeks 0 and 16, body weight was assessed using a calibrated scale. Body composition and visceral fat were measured by dual x-ray absorptiometry. Insulin resistance was assessed with the homeostasis model assessment index and the predicted insulin sensitivity index (PREDIM). Thermic effect of food was measured by indirect calorimetry over 3 hours after a standard liquid breakfast (720 kcal). In a subset of participants (n = 44), hepatocellular and intramyocellular lipids were quantified by proton magnetic resonance spectroscopy. Repeated measure analysis of variance was used for statistical analysis.

RESULTS

Among the 244 participants in the study, 211 (87%) were female, 117 (48%) were White, and the mean (SD) age was 54.4 (11.6) years. Over the 16 weeks, body weight decreased in the intervention group by 5.9 kg (95% CI, 5.0-6.7 kg; P < .001). Thermic effect of food increased in the intervention group by 14.1% (95% CI, 6.5-20.4; P < .001). The homeostasis model assessment index decreased (-1.3; 95% CI, -2.2 to -0.3; P < .001) and PREDIM increased (0.9; 95% CI, 0.5-1.2; P < .001) in the intervention group. Hepatocellular lipid levels decreased in the intervention group by 34.4%, from a mean (SD) of 3.2% (2.9%) to 2.4% (2.2%) (P = .002), and intramyocellular lipid levels decreased by 10.4%, from a mean (SD) of 1.6 (1.1) to 1.5 (1.0) (P = .03). None of these variables changed significantly in the control group over the 16 weeks. The change in PREDIM correlated negatively with the change in body weight (r = -0.43; P < .001). Changes in hepatocellular and intramyocellular lipid levels correlated with changes in insulin resistance (both r = 0.51; P = .01).

CONCLUSIONS AND RELEVANCE

A low-fat plant-based dietary intervention reduces body weight by reducing energy intake and increasing postprandial metabolism. The changes are associated with reductions in hepatocellular and intramyocellular fat and increased insulin sensitivity.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02939638.

Children and adults should avoid consuming animal products to reduce risk for chronic disease: YES

The consumption of animal products exposes humans to saturated fat, cholesterol, lactose, estrogens, and pathogenic microorganisms, while displacing fiber, complex carbohydrates, antioxidants, and other components needed for health. In the process, consumption of animal products increases the risk for cardiovascular disease, cancer, diabetes, obesity, and other disorders. This dietary pattern also promotes the growth of unhealthful gut bacteria, fostering, among other things, the production of trimethylamine N-oxide, a proinflammatory compound associated with cardiovascular and neurological diseases. When omnivorous individuals change to a plant-based diet, diet quality as measured by the Alternate Healthy Eating Index improves, and the risk of these health problems diminishes. Planning for nutrient adequacy is important with any diet. However, a diet based on vegetables, fruits, whole grains, and legumes, supplemented with vitamin B-12, is nutritionally superior to diets including animal products and is healthful for children and adults.

Children and adults should avoid consuming animal products to reduce the risk for chronic disease: Debate Consensus

The present debate outlined opposing views regarding the role of animal products in human diets. The YES position argues that the health benefits and safety of plant-based diets have been clearly established by consistent findings of randomized trials and observational studies; that animal products skew the diet toward saturated fat, excess protein, cholesterol, lactose, and exogenous hormones; and that vulnerable populations are better nourished by vegetables, fruits, legumes, and whole grains than by striated muscle and cow milk. In contrast, the NO position asserts that animal foods are not only benign but are also key elements of the human omnivore diet, facilitating the global challenge of adequate essential nutrition. This view holds that the portrayal of animal foods as unhealthy is not supported by the evidence and that a restrictive vegan diet decreases nutritional flexibility and robustness, increasing risk for vulnerable population groups. Points of agreement and controversy were identified, as well as opportunities for further studies.