Luciana Baroni

Diet represents a key determinant of the body’s acid–base balance because foods are metabolized into non-volatile acids or bases. An increase in dietary acid load can elicit low-grade metabolic acidosis, which has been associated with systemic inflammation and the risk of adverse cardiometabolic conditions, including obesity. Potential renal acid load (PRAL) and Net Endogenous Acid Production (NEAP) represent the major markers of dietary acid load. The aim of this secondary analysis was to compare the acid load of four different diets and investigate its association with Body Mass Index (BMI) in a sample of the general population. In an online survey, the INVITA study, four dietary patterns (meat-eaters, fish-eaters, lacto-ovo-vegetarians, and vegans) were compared for their corresponding PRAL and NEAP values, and the associations of both parameters with BMI were evaluated. Multiple linear regression models were progressively adjusted for dietary pattern, energy intake, age, sex, physical activity, smoking status, and education level. The stepwise decrease in animal food consumption across the four dietary patterns was associated with a progressive reduction in dietary acid load, with vegan participants showing the lowest values. While PRAL did not prove consistently associated with BMI in this cohort, NEAP remained significantly associated with BMI even after full adjustment for lifestyle confounders (β = 0.032, p = 0.00013). However, because NEAP includes an anthropometric component based on body surface area, this association should be interpreted cautiously, as it may partly reflect mathematical coupling rather than a purely diet-derived effect. PRAL should be considered the more diet-specific marker, while NEAP represents a composite index combining dietary acid load and anthropometric scaling. Because PRAL and NEAP do not account for protein origin, future studies should assess whether diet-specific reference ranges could improve their comparisons for dietary patterns including mostly or exclusively plant protein.

The most investigated health and environmental effects of vegetarian diets (lacto-ovovegetarian and vegan) are actually well established in current research (1)(2)(3)(4), although some aspects remain controversial. This Research Topic offers valuable insights into some aspects of the sector, contributing to expanding current knowledge and providing some mechanistic interpretation.Wirnitzer et al. cross-sectionally investigated the underlying motivations and lifestyle preferences related to dietary choices, and the associations between these factors and basic health behaviors in 1350 Austrian school teachers and principals, via an online questionnaire. Health concerns (46.4%) emerged as the most significant reason for dietary choices and engagement in sports. Vegetarians represented 7.5% of the sample (5.2% lacto-ovo-vegetarians and 2.3% vegans), with a female prevalence, and their vegetable intake was significantly higher (92.9% in lacto-ovovegetarians and 93.5% in vegans, respectively) compared to omnivores. The Authors conclude that these educational figures, representing influential role models for their students, can contribute to public health strategies.In their 12-week VEGPREV study (Poland), Wisniewska et al. observed a more pronounced body weight (BW) loss in obese patients, who were randomly prescribed hypocaloric vegan (100% plant-based) and EAT-Lancet Planetary Health (50% plant protein of total protein) diets, compared to those from lacto-ovo-vegetarian (70% plant protein) and Mediterranean (30% plant protein) hypocaloric diet groups. Patients who consumed a traditional hypocaloric diet following the WHO recommendations (20% plant protein) did not show any BW reduction during the study period at all.In the two reports by Kahleova et al., the Authors examined whether plant-based diet indices (total plant-based dietary index-PDI, healthful-hPDI and unhealthful-uPDI) were associated with weight loss in adults with type 1 diabetes (T1DM) and in overweight adults. In a secondary analysis of a randomized trial, 58 adults with T1DM alternated between an ad libitum low-fat vegan diet and a portion-controlled energy-restricted omnivorous diet for 12 weeks. PDI and hPDI increased significantly in the vegan participants and were associated with weight loss, even after adjustment for changes in energy intake. Conversely, the portion-controlled group showed less change, while changes in the uPDI were not associated with weight loss.Another secondary analysis of a randomized cross-over trial conducted by the same team involved 62 overweight adults, who alternated between Mediterranean and low-fat vegan diets for 16 weeks, with a 4-week washout period. Both PDI and uPDI increased during the vegan diet period, in comparison to the Mediterranean diet period, while hPDI increased during both dietary interventions. Changes in PDI and uPDI were inversely associated with changes in BW, and the association remained significant also after adjusting for changes in energy intake. Conversely, no significant association was found between changes in hPDI and BW.The results obtained in the above three clinical trials suggest that replacing animal products with plant-based foods in a vegan diet may represent a valuable non-pharmacological intervention for weight loss, and can be beneficial in the management of overweight patients and patients with T1DM. Moreover, the effect of "unhealthy" plant-based foods on BW remains intriguing, since no negative effect was observed after their inclusion in the diet.This aspect has been addressed by Grea et al., who analyzed energy, nutrient contents and use of iodized salt in 964 plant-based meat substitutes on the German market. An average of 224 kcal, 13.3 g protein, 12.0 g fat, and 1.60 g salt were found per 100 g of product. Specifically, meat substitutes presented a more favorable nutritional composition compared to sausage substitutes.More than 85% of all products were labeled as vegan, and one third as organic. Nevertheless, the high heterogeneity of these products warrants a better characterization of their nutritional profiles.In another secondary analysis of a randomized cross-over trial conducted by Kahleova et al. on 62 overweight adults, the dietary acid load decreased significantly within the low-fat vegan diet and was associated with weight loss, suggesting that the alkalizing effect may be an independent mechanism by which a vegan diet can promote weight loss.Moreover, in their cohort study, Yao et al. evaluated the distinct metabolomic signatures in long-term Chinese vegetarians and omnivores, and their association with a panel of cardiometabolic risk factors. By integrating metabolomic data with detailed dietary analysis, this study identified 17 differential metabolites, 11 upregulated and 6 downregulated in vegetarians, some of which associated with specific plant-foods and favorably associated with obesity indices, blood pressure, lipid profiles, and insulin sensitivity. This identification of unique serum metabolomic profiles in vegetarians provides mechanistic insights into the diet-metabolite-health axis, supporting the current evidence that vegetarian diets are associated with reduced risks of cardiometabolic diseases.Tosi et al. assessed the nutritional status and dietary intakes in a cohort of 107 newbornmother dyads with altered biomarkers of cobalamin metabolism. Most mothers (71%) were omnivorous, 16% lacto-vegetarian, 12% lacto-ovo-vegetarian, and 1% vegan; 87% of mothers had been taking supplements during pregnancy (70.7% folic acid, 68.7% iron, 15% vitamin B12). Plasma vitamin B12 levels averaged 240 pg/ml, with supplemented mothers showing slightly higher levels compared to those who did not supplement (255.5±113 pg/ml vs 231.2±104 pg/ml). The Authors highlight that all dietary patterns could result in insufficient nutrient intakes, and current supplementation practices during pregnancy should be tailored.Finally,...

Parkinson’s disease (PD) is the second most common neurodegenerative disease, characterized by motor and non-motor symptoms that significantly impact patients’ quality of life. Beyond pharmacological treatments, nutrition plays a crucial role in the prevention and management of the disease. Nutritional interventions represent a pivotal strategy for improving clinical outcomes and quality of life in PD patients, addressing issues such as delayed gastric emptying, constipation, weight loss, malnutrition, and chewing or swallowing difficulties. A plant-based diet is particularly suitable for such patients, due to its high fiber content which can enhance gastrointestinal motility, thereby improving levodopa bioavailability, and potentially ameliorateing PD symptoms. For this reason, alongside neurological support, PD patients should receive nutritional counseling. Moreover, food choices can influence the risk of developing the disease: a high consumption of dairy products has been associated with an increased risk of PD; conversely, many plant foods could elicit neuroprotective effects thanks to beneficial phytochemicals such as flavonoids, especially anthocyanins. Furthermore, a moderate coffee consumption could reduce PD risk and progression. The aim of this review is to explore the impact of dietary factors on the risk and progression of PD, evaluate the therapeutic potential of specific foods and dietary patterns in disease management, and highlight the clinical significance of nutritional interventions, specifically focusing on plant-based diets.

Background/Objectives: Levels of lipopolysaccharide (LPS), arachidonic acid (AA), and advanced glycation end products (AGEs) are higher in the brain of subjects affected by cognitive impairment and Alzheimer’s disease (AD), compared to a healthy brain. Methods: In this narrative review, articles were selected with data on these three key dietary compounds relevant to neuroinflammation and cognitive impairment in order to provide practical dietary advice to reduce the risk of diseases affecting cognition. Results: Triggered by LPS and AGEs in food, inflammatory cytokines can enter the brain and stimulate microglial activation, inflammation, and oxidative damage. AA can elicit neuroinflammation by increasing leukotriene-A4 and prostaglandin-E2 production. Increased levels of neuroinflammation are associated with poorer cognition in AD. Discussion: A dietary reduction of LPS, AA, and AGEs could slow progression and reduce the risk of cognitive impairment and AD by reducing neuroinflammation through several mechanisms. The avoidance of foods that are highest in LPS, AGEs, and AA (dairy products, pork, poultry, beef, and seafood) and the emphasis on foods lowest in LPS, AGEs, and AA (fruits, vegetables, boiled whole grains, beans, raw nuts, and seeds) can reduce neuroinflammation and risk of cognitive impairment and AD. Conclusions: Reduction of chronic neuroinflammation with dietary changes may represent a novel approach to the treatment of AD and cognitive decline.

In Eastern Europe, the number of vegetarians is growing, and the number of people adhering to Christian Lents is traditionally high. However, data on the nutritional value of plant-based diets in this part of the world are limited. The aim of this study was to compare the nutritional intakes of three groups with different plant-based patterns with that of omnivores in Russia, Moscow region. The nutrient intakes of 46 vegans, 49 lacto-ovo-vegetarians, 42 people who adhered to Orthodox Great Lent, and 48 omnivores were assessed. The food frequency questionnaire method was used for data collection and analysis. The differences in absolute and calorie adjusted nutrient intakes between the groups were analysed. Additionally, a pairwise comparison of the general plant-based group (combined of the vegan, lacto-ovo-vegetarian, and Great Lent samples) and the omnivorous groups was conducted. Vegan diet was the most favourable in micronutrient composition. The intake of many micronutrients increased when switching to a more plant-based diet from a more animal-based one. The opposite association was observed only for selenium and vitamins D and B₁₂. Fasting people consumed more iodine and n-3 polyunsaturated fatty acids; however, after the calorie content was standardized, the omnivores caught up with them. The omnivores had the largest list of dietary inadequacies: they significantly more often than all other groups had inadequate intake of cholesterol (excessive), fibre, potassium, magnesium, iron, and vitamins B₁, B₆, B₉, and E (insufficient). Inadequate intake of polyunsaturated fatty acids, calcium, iodine, chromium, molybdenum, and zinc; or vitamins B₂, PP, H, B₁₂, and D was observed rather often in all the studied groups. Although, the vegan diet was richer in most micronutrients, plant products often contain substances that reduce the bioavailability of various nutrients, which can partially affect their status in the body, and, thus, may increase the need in them in vegetarians and fasters.

Levels of lipopolysaccharide (LPS), arachidonic acid (AA), and advanced glycation end products (AGEs) are higher in the brain of subjects affected by cognitive impairment and Alzheimer’s disease(AD), compared to a healthy brain. Inflammatory cytokines, triggered by LPS and AGEs in food, can enter the brain via active transport and induce microglial activation, inflammation, and oxidative damage. AA can elicit neuroinflammation by increasing leukotriene-A4 and prostaglandin-E2 production. Increased levels of neuroinflammation are associated with poorer cognition in AD. A dietary reduction of LPS, AA, and AGEs could reduce risk and slow progression of cognitive impairment and AD by reducing neuroinflammation, through multiple mechanisms. The avoidance of foods that are highest in LPS, AGEs, and AA (dairy products, pork, poultry, beef, and seafood) and the emphasis on foods lowest in LPS, AGEs, and AA (fruits, vegetables, boiled whole grains, beans, raw nuts, and seeds) can reduce neuroinflammation and risk of cognitive impairment and AD. Reduction of chronic neuroinflammation with dietary changes may represent a novel approach to treatment of AD and cognitive decline.

Strong evidence supports the paramount importance of the composition of the diet for health. Not only diet should provide nutritional adequacy, but some foods and dietary components can also support the management of common chronic diseases, with mechanisms independent of nutritional adequacy. Among the various intervention diets, low-fat vegan diets have been shown to be effective for cardiometabolic health, mainly influencing insulin resistance, adiposity, and blood lipids. This type of diet relies on reducing or eliminating all added fats and choosing low-fat foods, mainly unprocessed whole-plant foods. We hereby propose a tool for planning low-fat vegan diets, the VegPlate Low-Fat (VP_LF), which has been obtained from a specific adaptation of the VegPlate method, which was already presented in previous publications for adults and some life stages and situations. The reduction in fats in the diet, which ranges between 10% and 15% of total energy, and the varied inclusion of foods from plant groups make it easier to provide adequate amounts of all nutrients with a normal- or lower-calorie intake, in comparison with diets that do not limit fat intakes. We expect that this new proposal will help nutrition professionals embrace low-fat diets as a first-line intervention for individuals affected by different health conditions who can benefit from these diets.

There is a growing interest in vegetarian diets among the world population, and this has implications for public health

Vegetarian diets are plant-based diets including all the edible foods from the Plant Kingdom, such as grains, legumes, vegetables, fruits, nuts, and seeds. Dairy and eggs can be added in small amounts in the lacto-ovo-vegetarian subtype, or not at all in the vegan subtype. The abundance of non-processed plant foods—typical of all well-planned diets, including vegetarian ones—can provide the body with numerous protective factors (fiber, phytocompounds), while limiting the intake of harmful nutrients like saturated fats, heme-iron, and cholesterol. The beneficial effects on health of this balance have been reported for many main chronic diseases, in both observational and intervention studies. The scientific literature indicates that vegetarians have a lower risk of certain types of cancer, overall cancer, overweight-obesity, type 2 diabetes, dyslipidemia, hypertension, and vascular diseases. Since the trend of following a vegetarian diet is increasing among citizens of developed countries, the knowledge in the field will benefit from further studies confirming the consistency of these findings and clarifying the effects of vegetarian diets on other controversial topics.