Macronutrient and micronutrient intake in vegetarian and non-vegetarian groups of young adults

Plant-based diets have gained popularity, especially in young age groups. This diet has shown many health benefits, however, following an unbalanced plant-based diet may lead to nutrient insufficiency. This study aims to compare the intake of macronutrients (calories, protein, fat, carbohydrates) and micronutrients (iron, calcium, vitamin B1) between the vegetarian and non-vegetarian groups of young adults. The 2x24h food recall was used to assess the food intake. A total of 140 participants (mean age 25.81 ± 6.64, 36% male and 64% female) participated in this study and they were divided into the vegetarian (n=65) and the non-vegetarian (n=75) groups. The results indicate that the vegetarian group has a lower intake (p< 0.001) for calories, protein, and fat compared to the non-vegetarian group. They also have a lower intake (p< 0.001) of iron and calcium, but a higher intake (p< 0.05) of vitamin B1 as compared to the non-vegetarian group. The source of foods was found to be varied in the vegetarian group but they consumed less amount of foods compared to the non-vegetarian group. This study can be used as educational materials for emphasizing the behavioral change on the importance of a balanced plant-based diet and promoting good and sustainable dietary practices.


Introduction
Vegetarian diets have become increasingly popular in the last decades [1].Around 2-10% of the population in the high-income countries have identified themselves as vegetarians [2] and this number keeps increasing yearly.Vegetarian diets also known as plant-based diets eliminate or restrict the consumption of foods derived from animals, such as fish, poultry, eggs, dairy products, and meat [3].Those who follow a plant-based diet might replace animal food products with plant-based options such as legumes, nuts, and grains, and for some people, without permanently avoiding animal-based foods [4].Some people may still consume dairy and eggs (ovo-lacto vegetarian) or fish (pescetarian) in moderation, but they limit the consumption of red meat and poultry [5].The concern of sustainable eating has been increased in the past decades by addressing the gas-emission effect as a result of animal barns, ethical issues about animal care, and the threat of animal-borne diseases [6].These become the main reasons for consumers to shift their diet to plant-based [1,6].In addition, the potential allergies to dairy products and lactose intolerance have fuelled the popularity of plant-based alternatives for milk products [6].
The health benefits of vegetarian diets also contribute significantly to the growing popularity of plant-based diets [2,3,6].This diet has been reported to be associated with a lower risk of obesity and type 2 diabetes [3,5].Moreover, evidence suggests that people implementing a plant-based diet were able to reduce the risk of coronary heart disease and cerebral vascular diseases by 40% and 30% respectively [3].Plant-based diet has also been reported to be closely associated with lowering cancer 1302 (2024) 012081 IOP Publishing doi:10.1088/1755-1315/1302/1/012081 2 risk [7,8].This mechanism can be answered via a high intake of fruits, vegetables, and whole grains in vegetarian diets, and this consumption pattern has been reported to be associated with a lower risk of colorectal, pancreatic, and prostate cancer due to high antioxidants and fibers contents in the diets [6][7][8].
However, vegetarian diets should be followed with caution.The long-term effects of becoming vegetarian can lead to a lower consumption of protein and calcium and these conditions may accelerate bone density loss and bone fractures [6,9].This risk is even higher for those following a strict vegan diet [9].Moreover, no red meat consumption influences the low level of heme iron in blood and this will impact to the low concentration of hemoglobin in red blood cells [6,10] increasing the risk of iron deficiency and anemia in vegetarians or vegans [11].However, vegetarians who eat a variation and right amount of whole grains, nuts, seeds, dried fruits, green leafy vegetables, and fortified cereals were reported to have sufficient intake of iron [10].People who consume an unbalanced vegetarian diet may also not obtain enough micronutrients, such as zinc, vitamin B12, vitamin D, and vitamin B1 from their meals [6].The objective of this study was to compare the nutrient intake of macronutrients and micronutrients between the vegetarian and the non-vegetarian groups in young adults.The macronutrient includes the total energy intake, protein, fat, and carbohydrates while the total intake for iron (Fe), thiamine (vitamin B1), and calcium (Ca) was also calculated as micronutrient intake.In this study, the vegetarian group refers to those having a plant-based diet by strictly excluding meat and poultry but they (for some participants) may include eggs, dairy, and fish while the non-vegetarian group refers to those having a normal dietary pattern without any meat and animal-based meal restriction [12].This study was also aimed to encompass one of the Sustainable Development Goals (SDGs) addressing good health and wellbeing that focuses on vegetarian intake aimed for highlighting sustainable and healthy eating.

Participants and ethic
There was a total of 140 participants joined in this study (mean age 25.8 ± 6.6, 36% male and 64% female).From these numbers, 65 participants were included in the vegetarian group (mean age 26.4 ± 3.6, 35% male and 65% female) while 75 participants were included in the non-vegetarian group (mean age 25.3 ± 8.4, 37% male and 63% female).A consent form was obtained at the beginning of the test detailing the objective of the study and the data collection procedures.In addition, verbal consent was also asked from the participants.All the participation was voluntary.The methodology has been approved for its data collection and follows the declaration of Helsinki of using human subjects.

Food recall 2x24 hours
The food intake was collected using the food recall method [13].Food recall is a method to assess how much food is consumed and how it varies.This is a structured interview that is intended to capture detailed information about all foods and drinks consumed by the participants in the previous days [14].The dietary data can be used to assess total dietary intake and relate it to specific aspects of the dietary requirement or nutritional needs as well as to find the correlation with certain diseases and health [15,16].In this study, food recall was collected for two days (2x24 hours), consisting of 1 weekday and 1 weekend in the same week.The method followed a study reported by Bailey [17], in which the participants were interviewed one-by-one using a face-to-face method.The interview mostly asked about participants' foods and beverages consumption in the previous days (1 day during weekday and 1 day during weekend).According to Racette [18] people may have different consumption patterns during weekend and weekday suggesting a higher consumption with more meal variations during weekend than weekday [19].Therefore, in this study, the food recall was conducted on both weekday and weekend [20,21].The meals were identified, and the main ingredients of the meals were also defined (for example: Bolognese pasta may consist of pasta, beef, tomato sauces, and cheese as their main ingredients).The cooking process was also asked to ensure whether there were certain ingredients added to the meals that may change the nutrient content significantly (i.e. oil used in frying) [22].For the coffee and tea consumption, the addition of sugar and milk into the beverages was also asked to ensure the additional calories and other nutrients in the beverages due to the presence of sugars and milk.The interview required around 15-20 minutes per participant.

Data analysis
The total intake for macronutrients (energy, protein, fat, and carbohydrates) and micronutrients (iron, vitamin B1, and calcium) were calculated for both weekdays and weekends.The average data for both days were then merged and calculated.The Indonesian food composition table (DKBM) was used to measure the nutrient intake of macronutrients and micronutrients [23].An independent student t-test for two groups (comparing the vegetarian and the non-vegetarian) was conducted to analyse if there was a significant difference in macronutrient and micronutrient intake between these groups.A significance level of p< 0.05 was used in the test.The statistical software of XLSTAT (Addinsoft, France, version 2019.2.2) was used to analyse and compute the data.

The comparison of macronutrients intake between the vegetarian and the non-vegetarian
There results for the differences of energy (calories) (p< 0.001) and carbohydrate (p< 0.001) intake between the vegetarian and the non-vegetarian group are presented in Figure 1.The total energy intake based on 2x24 hours of recall was shown to be significantly higher in the non-vegetarian group (1586 ± 710 kcal/day) compared to the vegetarian group (899 ± 185 kcal/day).Total carbohydrate intake for the non-vegetarian group was also higher (251± 115 grams/day) as compared to the vegetarian group (157 ± 50 grams/day).Based on the results, rice, oil, and meat were the main ingredients contributing to the total calorie intake for the non-vegetarian group while rice and legumes were the main ingredients that significantly contribute to the total calorie intake of the vegetarian group.For the carbohydrate intake, the main carbohydrate sources for the non-vegetarian groups were found to be rice, noodles, fritters, and wheat-based foods such as bread and bakery products.Interestingly, the vegetarian groups mainly consumed fruits as their carbohydrate source based, thus, lowering the total calories (energy) intake in this group.Vegetarian or plant-based diets exclude animal products including red meat, poultry, fish, eggs, and dairy-based products such as yogurt and cheese [24], however, some groups still consume limited amounts of fish, eggs or dairy products.Moreover, people following a vegan diet also minimize processed food, this includes removing foods with excess sugar, refined fat, and oil, as well as reducing salt [25].Thus, a plant-based diet results in a lower caloric intake compared to a normal diet [9].A study from Davey et al [26] also suggests that a diet pattern removing meat and meat-based food resulted in lower calorie and cholesterol intake since plant-based food is rich in phytosterol with zero cholesterol content [26].Corroborating with our results, plant-based diet has been reported as a healthier diet due to the limitation of calorie and carbohydrate intake, this diet also has been proposed as a therapeutic strategy for reducing overweight and obesity as well as maintaining normal body weight [27].
Based on this study, the total calorie intake in the vegetarian groups was considered as low.This may occur because people who follow vegetarian diets may follow a strict diet for weight loss, thus they may limit their food consumption, and as a result, lower the total calorie intake [2,28].Moreover, the carbohydrate sources from fruits that were mainly consumed by the vegetarian group also contributed to the lower energy consumption for this group.In general, fruits are considered low in calories and high in fiber.This will influence satiety control and result in a delay for the next meal [29].This may be the reason for the vegetarian group to have less amount of food consumed compared to the non-vegetarian.The amount of fiber consumed from fruits may increase the satiety levels for this group, thus delaying the next meals and resulting in a lower intake of calories.In addition, our results also revealed that there were greater differences in the cooking process between the non-vegetarians (they have consumed mainly fried and processed foods) and the vegetarians (they have consumed mainly whole foods such as legumes, and vegetables, minimally processed) which also contributes to the calorie and carbohydrate intake from oil and fat [26].The non-vegetarian group has a significant quantity of fried meals which were cooked with deep fried method.The fat content from the frying oil can contribute significantly to the increase in calorie intake [26].Moreover, processed foods were also considered to have high fat content and this also confer the significant addition of calories in the non-vegetarian group.Figure 2 presents the protein and fat intake respectively.The protein intake was higher (p< 0.001) in the non-vegetarian group (75.7 ± 34.2 gram/day) compared to the vegetarian group (33.3 ± 22.7 gram/day).Moreover, the fat intake was also found to be significantly higher (p< 0.001) in the nonvegetarian group (37.0 ± 24.5 grams/day) compared to the vegetarian group (11.4 ± 5.8 grams/day).These results corroborate the previous study which concludes that vegetarian diets tend to have lower calories, saturated fat, and cholesterol intake as compared to the normal diet [26].Vegetarian diet removes partially or entirely the meat and animal-based foods, in which these types of foods become protein and fat sources [6].By removing or reducing the meat or animal-based foods will directly reduce the fat and protein intake.Based on the previous study, people following plant-based diets have been reported to have a lower amount of fat intake compared to non-vegetarians [30].The same results were also reported by Davey et al [26] concluding that total fat intake in the group applying a vegetarian diet was considered to be half as compared to the people having a normal diet.In this study, the protein intake of the vegetarian group was lower by almost 50% than the non-vegetarian group.Based on the results, meat, poultry, and eggs were the main sources of protein intake in the non-vegetarian group while tempeh, tofu, and nuts were the main food ingredients that provided significant amount of protein in the vegetarian group.Vegetarians can get a sufficient amount of protein from plant-based proteins such as legumes and nuts, however, the quality of protein or the essential amino acid composition may not meet the recommendation of body requirements [1,31].Therefore, it is recommended that those having a vegetarian diet to watch their meals and ensure that they have sufficient protein intake [31].This practice can be implemented through eating different variations of meals, especially the source of plant protein [31].
In this study, the vegetarian group consumed less quantity of protein-sourced foods, and they did not compensate for the meat to be replaced by consuming more legumes, nuts or wholegrain.This resulted in a low protein intake for the vegetarian group, since they eat the protein source in a low quantity.Tempe and tofu are considered as food ingredients with good source of protein and these foods are commonly found in Indonesian dietary patterns as plant-based protein [32].However, in order to meet dietary recommendations of protein intake, the substitution of plant-based proteins like tempeh and tofu should be in the right amount for vegetarians to avoid protein deficiency [31].In this case, the quantity of protein-sourced meals needs to be increased almost two times to meet the dietary recommendation for protein intake.The results of macronutrient intake between the vegetarian and non-vegetarian groups found in this study corroborate a previous study reported by Lau et al [9] addressing a lower intake of calories, protein, and fat in vegetarians compared to normal diets.The same study also suggests to increase the quantity of protein meals for vegetarians.

The comparison of micronutrient intake between vegetarian and non-vegetarian group
Figure 3 demonstrates the intake of iron and calcium respectively.The results indicate that the vegetarian group has a lower intake of iron (p< 0.001) and calcium (p< 0.001) compared to the non-vegetarian group.The total intake of iron for the vegetarian group was not even half (11.7 ± 7.7 mg/day) compared to the non-vegetarian group (25.2 ± 15.6 mg/day).Milk, meat, and poultry were recorded as the main sources of iron in the non-vegetarian groups.These foods contribute to a higher amount of iron intake for this group.In contrast, for the vegetarian group, the source of iron was mainly from leafy vegetables such as spinach and breakfast cereal.We have also found that only a few of the participants in the vegetarian group consumed dairy products and they did not consume any animal-based meals in the diet.This contributes to a very low consumption of iron since this micronutrient (Fe) is abundantly found in meat or animal-based products [6,10].Therefore, the vegetarian group who did not consume meat may develop a high risk of iron deficiency [6].However, iron has been fortified in different food products such as breakfast cereals, flour, bread, etc.Despite the fortification, these types of foods were also rarely consumed by the vegetarian groups based on their food recall results, thus contributing to the insufficiency of iron for this group.

Figure 3. Iron and calcium intake between the vegetarian and non-vegetarian group
The calcium intake was also recorded to be lower in the vegetarian diet (493.7 ± 183.4 mg/day) compared to the non-vegetarian diet (1465.5 ± 705.3 mg/day).The main source of calcium in the nonvegetarian diet was recorded to be dairy products (milk, yogurt) as well as fish and seafood.These ingredients were not consumed in the vegetarian group, and as a consequence, lowering the calcium intake for this group.The calcium intake in the vegetarian group was not sufficient and did not meet the national recommendation for daily calcium intake (1000 mg/day for healthy adults, non-pregnant) [23].The vegetarian groups obtained their daily calcium intake mainly from breakfast cereals and leafy vegetables.As reported in a study by Craig [6], people who follow a plant-based diet may suffer inadequate amounts of iron and calcium.They have also been reported to be more prone to chronic anemia [6,10] and bone fractures [9,11] due to insufficient amounts of these essential minerals.Additional intake for these two essentials micronutrients (Fe and Ca) may be needed and sourced from different meals that are dense with these nutrients.Moreover, taking additional supplements may be suggested if the insufficiency occurred in a long time and cannot be filled in through meals.

Figure 4. Thiamine (vitamin B1) intake between the vegetarian and the non-vegetarian group
The intake of vitamin B1 is presented in Figure 4.The results show that the vegetarian group has a significantly higher (p< 0.05) intake of vitamin B1 compared to the non-vegetarian group.The high consumption of vitamin B1 in the vegetarian group (1.1 ± 0.7 mg/day) was mainly sourced from whole grains and legumes while these ingredients were consumed less in the non-vegetarian group, thus this group having a lower intake of B1 (0.6 ± 0.4 mg/day).Whole grains and legumes were considered as good sources of vitamin B complex, including thiamine (B1) [6,30] therefore, by consuming these foods, the vegetarian group was able to meet their daily recommendation of vitamin B1 (1-1.2 mg, healthy adults' population).In contrast, those who had normal diets were demonstrated to have a deficiency for vitamin B1 since they did not consume legumes equally as those having vegetarian diets.
Plant-based diet is considered as a nutrient-dense diet and packed with fibers.It has been reported that plant-based diets have higher vitamins and minerals compared to normal diets [6,30].However, a plant-based diet can be rather healthy or unhealthy, depending on the food choice [12].The healthy plant-based diet focuses on mainly unprocessed food (whole foods) and it has been recommended to eat more whole and raw food such as fruits, vegetables, whole grains, legumes, nuts, and seeds compared to processed foods (ready-to-eat meals, canned foods).In contrast, an unhealthy plant-based diet may consist of high quantities of processed and ultra-processed foods such as food with high amounts of refined sugars, refined grains, sugar-sweetened beverages, and desserts [12].This type of food mostly was selected due to convenience factors such as easy to prepare, easy to find at any supermarket, and cheap.However, these types of foods should be limited to be consumed since they are not nutrient-dense and lack of essential nutrients such as vitamins and minerals.

Conclusion and recommendations
This study concludes that the vegetarian group has a lower intake of calories, protein, fat, carbohydrates iron, and calcium while they demonstrate a higher consumption of vitamin B1.The vegetarian groups consumed various types of foods; however, they ate less quantity of foods.Most of the participants in the vegetarian group them were failed to meet their daily nutrition intake requirement.In our study, we were using 2x24h food recalls to measure participants' food intake.However, this method has limitations since it cannot capture the "true" diets based on 1-2 days of recall only.A single administration of a 24-hour recall is unable to capture day-to-day variations of food intake and this may be leading to potential bias in this study.It was suggested to conduct food recall for a minimum of 8 days to obtain a "true" representative intake and to reduce the effect of error due to day-to-day variability in the food intake measurement.We also suggest including other food intake measurements such as food frequency or food propensity questionnaires for future studies to capture the "food habits" and diet patterns in more precise ways.Lastly, we recommend increasing the number of participants to confirm the results for future studies.

Figure 1 .
Figure 1.Energy (calories) and carbohydrate intake between the vegetarian and the non-vegetarian group.

Figure 2 .
Figure 2. Protein and fat intake between the vegetarian and the non-vegetarian group.