Protein dietary reference intakes may be inadequate for vegetarians if low amounts of animal protein are consumed

The Importance of Dietary Protein Quality in Mid- to High-Income Countries

In wealthy countries, the protein intake of adults is usually considered to be adequate, and considerations of protein quality are often deemed irrelevant. The objective was to examine dietary protein intakes of adults in developed countries in the context of dietary protein quality. An analysis of NHANES population data on actual protein intakes in the United States (a developed country) demonstrated that for a dietary Digestible Indispensable Amino Acid Score (DIAAS) of 100%, 11% of the adult (19-50 y) population had habitual protein intakes below the Estimated Average Requirement (EAR) and 22% below the Recommended Dietary Allowance. The percentage of the population with utilizable protein intakes potentially falling below the EAR increased as the assumed DIAAS declined. Analysis of the NHANES data and several other datasets also indicated that total protein intakes can be limiting or close to limiting for the elderly and some vegetarians and vegans. Here, lower dietary protein quality can potentially lead to inadequate utilizable protein intakes. For many people in specific physiological states (e.g., weight loss, endurance sports, resistance exercise) attempting to meet higher dietary protein targets often with accompanying lowered energy intakes, low dietary protein quality can lead to protein calories expressed as a proportion of total calories, falling outside what may be acceptable limits (maximum of 30% protein calories from total calories). In general, individuals within the adult population may be susceptible to macronutrient imbalance (whenever total protein intakes are high, daily energy intakes low) and for diets with lower protein quality (DIAAS <100%). Our analysis shows that dietary protein quality is relevant in mid- to high-income countries.

Nitrogen Balance at the Recommended Dietary Allowance for Protein in Minimally Active Male Vegans

Vegan diets have gained popularity in recent years for reasons including health benefits and concerns for animal welfare. Although these diets are considered to be nutritionally adequate, questions remain over whether the current protein recommendation (0.8 g/kg/d) is sufficient. Protein status is determined through a nitrogen balance analysis when the protein content of the diet is known. A negative balance indicates a catabolic state, and a positive nitrogen balance indicates an anabolic state. In healthy adults, nitrogen equilibrium is the expectation reflecting the net synthesis and breakdown of proteins. Currently, there are no known studies measuring nitrogen balance in strict vegan men fed the protein requirement. Eighteen minimally active vegan men received a 5-day eucaloric diet (protein content: 0.8 g/kg/d). On day five, 24 h urine was collected for nitrogen analysis. Both the mean absolute nitrogen balance (-1.38 ± 1.22 g/d) and the mean relative nitrogen balance (-18.60 ± 16.96 mg/kg/d) were significantly lower than zero (equilibrium) (p < 0.001). There were no correlations seen between nitrogen balance and age, years as vegan, or fat-free mass. Consuming 0.8 g/kg/d of protein is not adequate to produce nitrogen balance in men adhering to typical strict vegan diets for at least one year.

The VegPlate for Sports: A Plant-Based Food Guide for Athletes

Background: Nutrition strategies improve physiological and biochemical adaptation to training, facilitate more intense workouts, promote faster recoveries after a workout in anticipation of the next, and help to prepare for a race and maintain the body’s hydration status. Although vegetarianism (i.e., lacto-ovo and veganism) has become increasingly popular in recent years, the number of vegetarian athletes is not known, and no specific recommendations have been made for vegetarian dietary planning in sports. Well-planned diets are mandatory to obtain the best performance, and the available literature reports that those excluding all types of flesh foods (meat, poultry, game, and seafood) neither find advantages nor suffer from disadvantages, compared to omnivorous diets, for strength, anaerobic, or aerobic exercise performance; additionally, some benefits can be derived for general health. Methods: We conceived the VegPlate for Sports, a vegetarian food guide (VFG) based on the already-validated VegPlate facilitating method, designed according to the Italian dietary reference intakes (DRIs). Results: The VegPlate for Sports is suitable for men and women who are active in sports and adhere to a vegetarian (i.e., lacto-ovo and vegan) diet, and provides weight-based, adequate dietary planning. Conclusions: The VegPlate for Sports represents a practical tool for nutrition professionals and gives the possibility to plan diets based on energy, carbohydrate (CHO), and protein (PRO) necessities, from 50 to 90 Kg body weight (BW).

Dietary Intake and Circulating Amino Acid Concentrations in Relation with Bone Metabolism Markers in Children Following Vegetarian and Omnivorous Diets

Scientific studies reported that most vegetarians meet the total protein requirements; however, little is known about their amino acid intakes. We aimed to assess dietary intake and serum amino acid levels in relation to bone metabolism markers in prepubertal children on vegetarian and traditional diets. Data from 51 vegetarian and 25 omnivorous children aged 4–9 years were analyzed. Dietary intake of macro- and micronutrients were assessed using the nutritional program Dieta 5®. Serum amino acid analysis was performed using high-pressure liquid chromatography technique, 25-hydroxyvitamin D and parathormone–electrochemiluminescent immunoassay, and bone metabolism markers, albumin, and prealbumin levels using enzyme-linked immunosorbent assay. Vegetarian children had a significantly lower intake of protein and amino acids with median differences of about 30–50% compared to omnivores. Concentrations of four amino acids (valine, lysine, leucine, isoleucine) in serum varied significantly by diet groups and were lower by 10–15% in vegetarians than meat-eaters. Vegetarian children also had lower (p < 0.001) serum albumin levels compared to omnivores. Among bone markers, they had higher (p < 0.05) levels of C-terminal telopeptide of collagen type I (CTX-I) than omnivores. Correlation patterns between amino acids and bone metabolism markers differed in the vegetarian and omnivore groups. Out of bone markers, especially osteoprotegerin was positively correlated with several amino acids, such as tryptophan, alanine, aspartate, glutamine, and serine, and ornithine in vegetarians. Vegetarian children consumed apparently sufficient but lower protein and amino acids compared to omnivores. In circulation these differences were less marked than in the diet. Significantly lower amino acid intake and serum levels of valine, lysine, leucine, and isoleucine as well as the observed correlations between serum amino acids and biochemical bone marker levels indicated the relations between diet, protein quality, and bone metabolism.

Serum creatinine as an indicator of lean body mass in vegetarians and omnivores

Growing numbers of Americans are adopting vegetarian or vegan diets. While risk for some chronic conditions may be lower when following these diets, concern remains over the ability to consume adequate amounts of various nutrients, notably, protein. Knowing that serum creatinine is a reliable marker of muscle mass, this study examined the relationships between serum creatinine, lean body mass (LBM), handgrip strength, and protein intake in healthy vegetarian (n = 55) and omnivorous (n = 27) adults. Significantly higher protein intakes (+31%), LBM (+7%), serum creatinine (+12%) and handgrip strength (+14%) were observed for the omnivore participants compared to vegetarian participants. Positive correlations (p < 0.001) were noted between creatinine and LBM (R² = 0.42), creatinine and handgrip strength (R² = 0.41), protein intake and LBM (R² = 0.29), and handgrip strength and LBM (R² = 0.69). These data show that serum creatinine concentrations were lower in vegetarian women and men in comparison to their omnivorous counterparts and that serum creatinine concentrations correlate with LBM and strength in healthy adults, regardless of diet.

Vegan nutrition: a preliminary guide for health professionals

Since the beginning of the 21st century, interest in vegan diets has been rapidly increasing in most countries. Misconceptions about vegan diets are widespread among the general population and health professionals. Vegan diets can be health-promoting and may offer certain important advantages compared to typical Western (and other mainstream) eating patterns. However, adequate dietary sources/supplements of nutrients of focus specific to vegan diets should be identified and communicated. Without supplements/fortified foods, severe vitamin B12 deficiency may occur. Other potential nutrients of focus are calcium, vitamin D, iodine, omega-3 fatty acids, iron, zinc, selenium, vitamin A, and protein. Ensuring adequate nutrient status is particularly important during pregnancy, lactation, infancy, and childhood. Health professionals are often expected to be able to provide advice on the topic of vegan nutrition, but a precise and practical vegan nutrition guide for health professionals is lacking. Consequently, it is important and urgent to provide such a set of dietary recommendations. It is the aim of this article to provide vegan nutrition guidelines, based on current evidence, which can easily be communicated to vegan patients/clients, with the goal of ensuring adequate nutrient status in vegans.

Benefits of a plant-based diet and considerations for the athlete

Individuals may opt to follow a plant-based diet for a variety of reasons, such as religious practices, health benefits or concerns for animal or environmental welfare. Such diets offer a broad spectrum of health benefits including aiding in the prevention and management of chronic diseases. In addition to health benefits, a plant-based diet may provide performance-enhancing effects for various types of exercise due to high carbohydrate levels and the high concentration of antioxidants and phytochemicals found in a plant-based diet. However, some plant-based foods also contain anti-nutrional factors, such as phytate and tannins, which decrease the bioavailability of key nutrients, such as iron, zinc, and protein. Thus, plant-based diets must be carefully planned to ensure adequate intake and absorption of energy and all essential nutrients. The current narrative review summarizes the current state of the research concerning the implications of a plant-based diet for health and exercise performance. It also outlines strategies to enhance the bioavailability of nutrients, sources of hard-to-get nutrients, and sport supplements that could interest plant-based athletes.

Nutrient Intake and Status in Adults Consuming Plant-Based Diets Compared to Meat-Eaters: A Systematic Review

Health authorities increasingly recommend a more plant-based diet, rich in fruits, vegetables, pulses, whole grains and nuts, low in red meat and moderate in dairy, eggs, poultry and fish which will be beneficial for both health and the environment. A systematic review of observational and intervention studies published between 2000 and January 2020 was conducted to assess nutrient intake and status in adult populations consuming plant-based diets (mainly vegetarian and vegan) with that of meat-eaters. Mean intake of nutrients were calculated and benchmarked to dietary reference values. For micronutrient status, mean concentrations of biomarkers were calculated and compared across diet groups. A total of 141 studies were included, mostly from Europe, South/East Asia, and North America. Protein intake was lower in people following plant-based diets compared to meat-eaters, but well within recommended intake levels. While fiber, polyunsaturated fatty acids (PUFA), folate, vitamin C, E and magnesium intake was higher, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake was lower in vegetarians and vegans as compared to meat-eaters. Intake and status of vitamin B12, vitamin D, iron, zinc, iodine, calcium and bone turnover markers were generally lower in plant-based dietary patterns compared to meat-eaters. Vegans had the lowest vitamin B12, calcium and iodine intake, and also lower iodine status and lower bone mineral density. Meat-eaters were at risk of inadequate intakes of fiber, PUFA, α-linolenic acid (ALA), folate, vitamin D, E, calcium and magnesium. There were nutrient inadequacies across all dietary patterns, including vegan, vegetarian and meat-based diets. As plant-based diets are generally better for health and the environment, public health strategies should facilitate the transition to a balanced diet with more diverse nutrient-dense plant foods through consumer education, food fortification and possibly supplementation.

Screening of Twelve Pea (Pisum sativum L.) Cultivars and Their Isolates Focusing on the Protein Characterization, Functionality, and Sensory Profiles

Pea protein concentrates and isolates are important raw materials for the production of plant-based food products. To select suitable peas (Pisum sativum L.) for protein extraction for further use as food ingredients, twelve different cultivars were subjected to isoelectric precipitation and spray drying. Both the dehulled pea flours and protein isolates were characterized regarding their chemical composition and the isolates were analyzed for their functional properties, sensory profiles, and molecular weight distributions. Orchestra, Florida, Dolores, and RLPY cultivars showed the highest protein yields. The electrophoretic profiles were similar, indicating the presence of all main pea allergens in all isolates. The colors of the isolates were significantly different regarding lightness (L*) and red-green (a*) components. The largest particle size was shown by the isolate from Florida cultivar, whereas the lowest was from the RLPY isolate. At pH 7, protein solubility ranged from 40% to 62% and the emulsifying capacity ranged from 600 to 835 mL g⁻¹. The principal component analysis revealed similarities among certain pea cultivars regarding their physicochemical and functional properties. The sensory profile of the individual isolates was rather similar, with an exception of the pea-like and bitter attributes, which were significantly different among the isolates.

Frequency of legume consumption related to sociodemographic factors, health status and health-related variables among surveyed adults from Poland

OBJECTIVE

The aims of the study were: (i) to estimate the frequency of legume consumption in a study sample from Poland; (ii) to assess relationships between frequency of legume consumption and sociodemographic factors, health status and health-related variables and (iii) to describe the sociodemographic and health-related profiles of 'frequent', 'rare' and 'never legume consumers'.

DESIGN

A cross-sectional study with a self-administered questionnaire was conducted. χ2 test compared the distribution of sociodemographic, health status and health-related variables in accordance with frequency of legume consumption. Multiple correspondence analysis (MCA) revealed the sociodemographic and health-related profiles of 'frequent', 'rare' and 'never legume consumers'.

SETTING

Adult individuals from Poland.

PARTICIPANTS

The present study included 1135 adults aged 18-80 years.

RESULTS

Only 22·8 % of all participants declared frequent legume consumption. The prevalence of 'rare' and 'never consumers' was 72·1 and 5·1 %, respectively. The MCA highlighted strong correspondence of sociodemographic factors, health status and health-related variables with the frequency of legume consumption.

CONCLUSIONS

Low frequency of legume consumption in a study sample of adults from Poland was strongly associated with male sex, low educational level, physical work, living in villages and small cities, and living with more than one co-resident; low legume consumption was also associated with sedentary lifestyle, no disease prevalence and no dietary supplementation.

Postprandial Metabolic Response to Rapeseed Protein in Healthy Subjects

Plant proteins have become increasingly important for ecological reasons. Rapeseed is a novel source of plant proteins with high biological value, but its metabolic impact in humans is largely unknown. A randomized, controlled intervention study including 20 healthy subjects was conducted in a crossover design. All participants received a test meal without additional protein or with 28 g of rapeseed protein isolate or soy protein isolate (control). Venous blood samples were collected over a 360-min period to analyze metabolites; satiety was assessed using a visual analog scale. Postprandial levels of lipids, urea, and amino acids increased following the intake of both protein isolates. The postprandial insulin response was lower after consumption of the rapeseed protein than after intake of the soy protein (p < 0.05), whereas the postmeal responses of glucose, lipids, interleukin-6, minerals, and urea were comparable between the two protein isolates. Interestingly, the rapeseed protein exerted stronger effects on postprandial satiety than the soy protein (p < 0.05). The postmeal metabolism following rapeseed protein intake is comparable with that of soy protein. The favorable effect of rapeseed protein on postprandial insulin and satiety makes it a valuable plant protein for human nutrition.

Benefits of Creatine Supplementation for Vegetarians Compared to Omnivorous Athletes: A Systematic Review

Background: Creatine monohydrate is a nutritional supplement often consumed by athletes in anaerobic sports. Creatine is naturally found in most meat products; therefore, vegetarians have reduced creatine stores and may benefit from supplementation. Objective: to determine the effects of creatine supplementation on vegetarians. Data sources: PubMed and SPORTDiscus. Eligibility criteria: Randomized controlled trials (parallel group, cross-over studies) or prospective studies. Participants: Vegetarians. Intervention: Creatine supplementation. Study appraisal and synthesis: A total of 64 records were identified, and eleven full-text articles (covering nine studies) were included in this systematic review. Results: Creatine supplementation in vegetarians increased total creatine, creatine, and phosphocreatine concentrations in vastus lateralis and gastrocnemius muscle, plasma, and red blood cells, often to levels greater than omnivores. Creatine supplementation had no effect on brain levels of phosphocreatine. Creatine supplementation increased lean tissue mass, type II fiber area, insulin-like growth factor-1, muscular strength, muscular endurance, Wingate mean power output, and brain function (memory and intelligence) in vegetarian participants. Studies were mixed on whether creatine supplementation improved exercise performance in vegetarians to a greater extent compared to omnivores. Limitations: Studies that were reviewed had moderate–high risk of bias. Conclusions: Overall, it appears vegetarian athletes are likely to benefit from creatine supplementation.

A Comparison of Dietary Protein Digestibility, Based on DIAAS Scoring, in Vegetarian and Non-Vegetarian Athletes

Vegetarian diets provide an abundance of nutrients when carefully planned. However, vegetarian diets may have lower protein quality compared to omnivorous diets, a reflection of less favorable amino acid profiles and bioavailability. Hence, the current recommended dietary allowance for protein may not be adequate for some vegetarian populations. The purpose of this study was to determine dietary protein quality using the DIAAS (Digestible Indispensable Amino Acid Score) method in vegetarian and omnivore endurance athletes. DIAAS scores reflect the true ileal digestibility of the indispensable amino acids that are present in food items, and these scores can be used to compute the available protein in diet plans. Thirty-eight omnivores and 22 vegetarians submitted seven-day food records that were analyzed for nutrient content, and DIAAS scores were computed by diet group. Average available protein (g) was compared along with participants’ lean body mass and strength (quantified using the peak torque of leg extension). DIAAS scores and available protein were higher for omnivorous versus vegetarian athletes (+11% and +43%, respectively, p < 0.05). Omnivorous participants had significantly higher lean body mass than vegetarian participants (+14%), and significant correlations existed between available protein and strength (r = 0.314) and available protein and lean body mass (r = 0.541). Based upon available protein, as determined through the DIAAS, vegetarian athletes in this study would need to consume, on average, an additional 10 g protein daily to reach the recommended intake for protein (1.2 g/kg/d). An additional 22 g protein daily would be needed to achieve an intake of 1.4 g/kg/d, the upper end of the recommended intake range.

Food processing for the improvement of plant proteins digestibility

Proteins are essential macronutrients for the human diet. They are the primary source of nitrogen and are fundamental for body structure and functions. The plant protein quality (PPQ) refers to the bioavailability, digestibility, and amino acid composition. The digestibility specifies the protein quantity absorbed by an organism relative to the consumed amount and depends on the protein structure, previous processing, and the presence of compounds limiting the digestion. The latter are so-called antinutritional factors (ANF), exemplified by phytates, tannins, trypsin inhibitors, and lectins. Animal proteins are known to have better digestibility than plant proteins due to the presence of ANF in plants. Thus, the inactivation of ANF throughout food processing may increase the PPQ. New food processing, aiming to increase the digestibility of plant proteins, and new sources of proteins are being studied for the animal protein substitution. Here, it is presented the impact of processing on the protein digestibility and reduction of ANF. Several techniques, such as cooking, autoclaving, germination, microwave, irradiation, spray- and freeze-drying, fermentation, and extrusion enhanced the PPQ. The emerging non-thermal technologies impact on protein functionalities but require studies on the protein digestibility. How to accurately determine and how to improve the protein digestibility of a plant source remains a scientific and technological challenge that may be addressed by novel or combining existing processing techniques, as well as by exploring protein-enriched by-products of the food industry.

Mung Bean Protein Supplement Improves Muscular Strength in Healthy, Underactive Vegetarian Adults

Although vegetarian diets are considered generally protective against chronic disease, nutrient deficiencies, including protein, are possible due to low bioavailability from plant-based sources. The consequences of inadequate dietary protein include reduced lean body mass (LBM) and muscle weakness. This study examined relationships between protein intake, strength, and LBM in 37 underactive vegetarians and recorded the impact of protein supplementation (18 g/day mung bean protein) on these indices utilizing an eight-week, randomized, controlled, feeding trial. Both handgrip and knee flexor and extensor strength were measured at baseline and week eight. At baseline, LBM was significantly related to grams of protein consumed daily. LBM was also correlated to grip strength (r = 0.569, p < 0.001) and lower body strength (r = 0.763 to 0.784; p < 0.001). Twenty-five vegetarians completed the feeding trial, including 11 in the protein supplementation group (PRO) and 14 in the control group (CON). At the end of the trial, LBM and strength did not differ significantly between groups. However, the average percent change for grip, flexor, and extensor strength did differ between PRO and CON participants (+2.9 ± 7.2% and −2.6 ± 7.3% respectively, p = 0.05). Thus, there were strong associations between dietary protein, LBM, and strength in vegetarians and an indication that supplementary vegetarian protein increased strength in the absence of exercise and independent of LBM.

Perspective: The Public Health Case for Modernizing the Definition of Protein Quality

Prevailing definitions of protein quality are predicated on considerations of biochemistry and metabolism rather than the net effects on human health or the environment of specific food sources of protein. In the vernacular, higher "quality" equates to desirability. This implication is compounded by sequential, societal trends in which first dietary fat and then dietary carbohydrate were vilified during recent decades, leaving dietary protein under an implied halo. The popular concept that protein is "good" and that the more the better, coupled with a protein quality definition that favors meat, fosters the impression that eating more meat, as well as eggs and dairy, is desirable and preferable. This message, however, is directly opposed to current Dietary Guidelines for Americans, which encourage consumption of more plant foods and less meat, and at odds with the literature on the environmental impacts of foods, from carbon emissions to water utilization, which decisively favor plant protein sources. Thus, the message conveyed by the current definitions of protein quality is at odds with imperatives of public and planetary health alike. We review the relevant literature in this context and make the case that the definition of protein quality is both misleading and antiquated. We propose a modernized definition that incorporates the quality of health and environmental outcomes associated with specific food sources of protein. We demonstrate how such an approach can be adapted into a metric and applied to the food supply.

Vegan Nutrition for Mothers and Children: Practical Tools for Healthcare Providers

As the number of subjects choosing vegan diets increases, healthcare providers must be prepared to give the best advice to vegan patients during all stages of life. A completely plant-based diet is suitable during pregnancy, lactation, infancy, and childhood, provided that it is well-planned. Balanced vegan diets meet energy requirements on a wide variety of plant foods and pay attention to some nutrients that may be critical, such as protein, fiber, omega-3 fatty acids, iron, zinc, iodine, calcium, vitamin D, and vitamin B12. This paper contains recommendations made by a panel of experts from the Scientific Society for Vegetarian Nutrition (SSNV) after examining the available literature concerning vegan diets during pregnancy, breastfeeding, infancy, and childhood. All healthcare professionals should follow an approach based on the available evidence in regard to the issue of vegan diets, as failing to do so may compromise the nutritional status of vegan patients in these delicate periods of life.

Effects of consuming a high-protein diet with or without soy protein during weight loss and maintenance: a non-inferiority, randomized clinical efficacy trial

OBJECTIVE

This 12-month randomized, non-inferiority clinical trial sought to determine the impact of consuming soy protein as part of an energy-restricted, high-protein diet on weight loss, body composition and cardiometabolic health.

METHODS

Seventy-one adults (58 female) with overweight or obesity (body mass index: 32.9 ± 3.6 kg m-2) were randomly assigned to consume three servings of soy (S) or non-soy (NS) protein foods per day for 12 months. All participants completed a group-based behavioural weight loss program lasting 4 months (M4), and follow-up assessments were completed at month 12 (M12).

RESULTS

Body weight was reduced in both groups at M4 (S: -7.0% ± 5.2%, NS: -7.1% ± 5.7%) and M12 (S: 3.6% ± 5.1%, NS: -4.8% ± 7.3%). Body weight reductions (mean difference [90% confidence interval]) were not different between S and NS at either time point (M4: -0.16% [-1.4, 3.6], P = 0.90; M12: 1.1% [-1.4, 3.6], P = 0.44). Differences in body fat mass loss were not different between S and NS at M4 (0.29 ± 0.84 kg, P = 0.73) or M12 (0.78 ± 1.5 kg, P = 0.59). Weight loss-induced improvements in cholesterol, triglycerides and blood pressure did not differ between S and NS.

CONCLUSION

These results indicate that soy-based protein foods can be effectively incorporated into an energy-restricted, high-protein diet for improving body weight, body composition and cardiometabolic health.

Position paper on vegetarian diets from the working group of the Italian Society of Human Nutrition

BACKGROUND

Interest in vegetarian diets is growing in Italy and elsewhere, as government agencies and health/nutrition organizations are emphasizing that regular consumption of plant foods may provide health benefits and help prevent certain diseases.

METHODS AND RESULTS

We conducted a Pubmed search, up to September, 2015, for studies on key nutrients (proteins, vitamin B12, iron, zinc, calcium, vitamin D, and n-3 fatty acids) in vegetarian diets. From 295 eligible publications the following emerged: Vegetarians should be encouraged to supplement their diets with a reliable source of vitamin B12 (vitamin-fortified foods or supplements). Since the plant protein digestibility is lower than that of animal proteins it may be appropriate for vegetarians to consume more proteins than recommended for the general population. Vegetarians should also be encouraged to habitually consume good sources of calcium, iron and zinc - particularly vegetables that are low in oxalate and phytate (e.g. Brassicaceae), nuts and seeds, and calcium-rich mineral water. Calcium, iron, and zinc bioavailability can be improved by soaking, germination, and sour-dough leavening that lower the phytate content of pulses and cereals. Vegetarians can ensure good n-3 fatty acid status by habitually consuming good sources of a-linolenic acid (walnuts, flaxseeds, chia seeds, and their oils) and limiting linoleic acid intake (corn and sunflower oils).

CONCLUSIONS

Well-planned vegetarian diets that include a wide variety of plant foods, and a reliable source of vitamin B12, provide adequate nutrient intake. Government agencies and health/nutrition organizations should provide more educational resources to help Italians consume nutritionally adequate vegetarian diets.

Vegan diets: practical advice for athletes and exercisers

With the growth of social media as a platform to share information, veganism is becoming more visible, and could be becoming more accepted in sports and in the health and fitness industry. However, to date, there appears to be a lack of literature that discusses how to manage vegan diets for athletic purposes. This article attempted to review literature in order to provide recommendations for how to construct a vegan diet for athletes and exercisers. While little data could be found in the sports nutrition literature specifically, it was revealed elsewhere that veganism creates challenges that need to be accounted for when designing a nutritious diet. This included the sufficiency of energy and protein; the adequacy of vitamin B12, iron, zinc, calcium, iodine and vitamin D; and the lack of the long-chain n-3 fatty acids EPA and DHA in most plant-based sources. However, via the strategic management of food and appropriate supplementation, it is the contention of this article that a nutritive vegan diet can be designed to achieve the dietary needs of most athletes satisfactorily. Further, it was suggested here that creatine and β-alanine supplementation might be of particular use to vegan athletes, owing to vegetarian diets promoting lower muscle creatine and lower muscle carnosine levels in consumers. Empirical research is needed to examine the effects of vegan diets in athletic populations however, especially if this movement grows in popularity, to ensure that the health and performance of athletic vegans is optimised in accordance with developments in sports nutrition knowledge.

Animal Proteins as Important Contributors to a Healthy Human Diet

Adequate protein intake is critical for health and development. Generally, protein of animal origin is of higher quality for humans owing to its amino acid pattern and good digestibility. When administered in mixtures it can enhance the quality of plant proteins, but its availability is often low in low-income communities, especially in young children, the elderly, and pregnant and lactating women, who have increased requirements and in whom high-quality protein also stimulates (bone) growth and maintenance. Although high protein intake was associated with increased type 2 diabetes mellitus risk, milk and seafood are good sources of branched chain amino acids and taurine, which act beneficially on glucose metabolism and blood pressure. However, high consumption of protein-rich animal food is also associated with adverse health effects and higher risk for noncommunicable diseases, partly related to other components of these foods, like saturated fatty acids and potential carcinogens in processed meat but also the atherogenic methionine metabolite homocysteine. In moderation, however, animal proteins are especially important for health maintenance in vulnerable persons.

Greenhouse gas emissions of realistic dietary choices in Denmark: the carbon footprint and nutritional value of dairy products

BACKGROUND

Dairy products are important in a healthy diet due to their high nutritional value; they are, however, associated with relatively large greenhouse gas emissions (GHGE) per kg product. When discussing the need to reduce the GHGE caused by the food system, it is crucial to consider the nutritional value of alternative food choices.

OBJECTIVE

The objective of this study was to elucidate the role of dairy products in overall nutrition and to clarify the effects of dietary choices on GHGE, and to combine nutritional value and GHGE data.

METHODS

We created eight dietary scenarios with different quantity of dairy products using data from the Danish National Dietary Survey (1995-2006). Nutrient composition and GHGE data for 71 highly consumed foods were used to estimate GHGE and nutritional status for each dietary scenario. An index was used to estimate nutrient density in relation to nutritional recommendation and climate impact for solid food items; high index values were those with the highest nutrient density scores in relation to the GHGE.

RESULTS

The high-dairy scenario resulted in 27% higher protein, 13% higher vitamin D; 55% higher calcium; 48% higher riboflavin; and 18% higher selenium than the non-dairy scenario. There was a significant correlation between changes in calcium and changes in vitamin D, selenium, and riboflavin content (P=0.0001) throughout all of the diets. The estimated GHGE for the dietary scenario with average-dairy consumption was 4,631 g CO2e/day.

CONCLUSIONS

When optimizing a diet with regard to sustainability, it is crucial to account for the nutritional value and not solely focus on impact per kg product. Excluding dairy products from the diet does not necessarily mitigate climate change but in contrast may have nutritional consequences.

Vegan lifestyle behaviors: an exploration of congruence with health-related beliefs and assessed health indices

This study aimed to investigate health belief as a major motive for diet and lifestyle behaviors of 100 vegans in the United States; and to determine congruence with selected health and nutrition outcomes. Response data from an administered questionnaire was analyzed. Statistical analyses determined the most common factors influencing diet choice; the number of vegans practicing particular lifestyle behaviors; body mass index; and prevalence of self-reported chronic disease diagnoses. Nutrient intakes were analyzed and assessed against Dietary Reference Intakes. Health was the most reported reason for diet choice (47%). In the health belief, animal welfare, and religious/other motive categories, low percentages of chronic disease diagnoses were reported: 27%, 11%, and 15%, respectively. There were no significant differences in health behaviors and indices among vegan motive categories, except for product fat content choices. Within the entire study population, health-related vegan motive coincided with regular exercise; 71% normal BMI (mean=22.6); minimal alcohol and smoking practices; frequently consumed vegetables, nuts, and grains; healthy choices in meal types, cooking methods, and low-fat product consumption; and adequate intakes for most protective nutrients when compared to reference values. But incongruence was found with 0% intake adequacy for vitamin D; and observation of excessive sodium use.

Nutritional evaluation of rapeseed protein compared to soy protein for quality, plasma amino acids, and nitrogen balance--a randomized cross-over intervention study in humans

BACKGROUND & AIMS

Plant proteins such as rapeseed have received little attention for human nutrition due to their high level of antinutritive compounds. Today, newer technologies can eliminate such compounds. The present intervention study aimed to evaluate nutritional and physiological properties of two manufactured canola proteins with special focus on their bioavailability in humans.

METHODS

28 healthy male subjects (ø 25 years) consumed 30.0 g protein (canola protein isolate--CPI, canola protein hydrolyzate--CPH or soy protein isolate--SPI) in a randomized, double-blind, cross-over study. Blood samples were regularly drawn over the 8-h postprandial period and a 24-h urine sample was collected.

RESULTS

True digestibility of the canola proteins determined in a separate rat assay showed 93.3% for CPI and 97.3% for CPH. In humans, consumption of either 30.0 g canola protein or soy protein mixed in a drink led to significant increases in plasma amino acids after 62.3 and 83.6 min, respectively. While the CPH produced an earlier response compared to CPI and SPI, total amino acid response (AUC for 8 h) was comparable between all interventions. The nitrogen balance between the three proteins tested showed no statistical differences.

CONCLUSIONS

High digestibility of rapeseed protein was found in rats. In humans, this is the first intervention study showing rapeseed protein (both isolate and hydrolyzate) as having a high nutritional quality and can be considered to be as efficient as soy protein for a postprandial amino acid response. This trial was registered at ClinicalTrials.gov Identifier: NCT01481584.

Sustainable diets for the future: Can we contribute to reducing greenhouse gas emissions by eating a healthy diet?

BACKGROUND

Food systems account for 18-20% of UK annual greenhouse gas emissions (GHGEs). Recommendations for improving food choices to reduce GHGEs must be balanced against dietary requirements for health.

OBJECTIVE

We assessed whether a reduction in GHGEs can be achieved while meeting dietary requirements for health.

DESIGN

A database was created that linked nutrient composition and GHGE data for 82 food groups. Linear programming was used iteratively to produce a diet that met the dietary requirements of an adult woman (19-50 y old) while minimizing GHGEs. Acceptability constraints were added to the model to include foods commonly consumed in the United Kingdom in sensible quantities. A sample menu was created to ensure that the quantities and types of food generated from the model could be combined into a realistic 7-d diet. Reductions in GHGEs of the diets were set against 1990 emission values.

RESULTS

The first model, without any acceptability constraints, produced a 90% reduction in GHGEs but included only 7 food items, all in unrealistic quantities. The addition of acceptability constraints gave a more realistic diet with 52 foods but reduced GHGEs by a lesser amount of 36%. This diet included meat products but in smaller amounts than in the current diet. The retail cost of the diet was comparable to the average UK expenditure on food.

CONCLUSION

A sustainable diet that meets dietary requirements for health with lower GHGEs can be achieved without eliminating meat or dairy products or increasing the cost to the consumer.