In this study, we found that pulses, seeds, nuts and PBDA were important sources of several key nutrients—such as protein, PUFA, folate and iron—in the diets of VGT and VGN Finnish children and adults. Our findings highlight the critical role of food fortification in supporting adequate intake of riboflavin, vitamin B12, calcium, and iodine in individuals following these diets. Furthermore, vitamin D fortification effectively supports adequate intake across all diet groups. In the diets of OMN Finnish children and adults, animal-source foods were major contributors to energy, protein, and several micronutrients, including vitamin B12, vitamin D, riboflavin, calcium, iodine, EPA, and DHA. Notably, EPA and DHA were absent in diets that excluded fish and eggs.

On average, children and adults across diet groups met the Nordic Nutrition Recommendations (NNR) 2023 for protein (E%) intake (recommended intake [RI], 10–20 E% for both children and adults) [1]. However, protein intake was lower in the VGN group compared to the OMN group, primarily due to the contribution of animal-source protein in the latter. Replacing animal protein sources—such as milk, meat, eggs, and fish—with plant-based alternatives raises concerns about protein quality and bioavailability, as plant proteins may contain antinutritional compounds that reduce bioavailability, and are limited in certain amino acids, including lysine, tryptophan (in cereals), methionine, and cysteine (in pulses) [32]. Still, increasing plant protein intake while reducing animal protein is considered beneficial, due to health-promoting components such as PUFAs and fiber present in plant sources (e.g., legumes) [33, 34]. A systematic review and meta-analysis found a positive association between higher total and animal protein intake and increased BMI, while low protein intake was not shown to impair growth in well-nourished Western children [35]. Previous studies have similarly reported lower protein content in PBDs compared to OMN diets [16, 24].

Average intakes of carbohydrates (RI for all 45–60 E%) and fiber (RI 2–3 g/MJ for children and ≥ 3 g/MJ for adults) were within the RI´s for all child groups as well as the adult VGN and VGT groups, but less than the RI´s in the adult OMN group. According to the FinDiet 2017 Study, approximately 70% of Finnish adults have inadequate carbohydrate intake, and only 11% of adult men and 2% of women meet the RI for fiber [13]. Similar challenges in the intake of carbohydrates have been reported in other Nordic countries [36]. In our study, the main source of carbohydrates was cereals, while on average fruit and vegetable consumption did not reach the RI of 500–800 g/d in any adult group [37]. PBDs, characterized by higher consumption of pulses, seeds, nuts, and vegetables, are associated with greater fiber intake [22]. Thus, the inclusion of these fiber-rich foods such as pulses, seeds, and nuts could substantially improve fiber intake in individuals following OMN diets.

Fat quality was more favourable in the VGN group among children and adults, as characterized by lowest intake of SFA (E%) and highest intake of PUFA (E%). To improve dietary fat quality, individuals following OMN diets could benefit from partially replacing foods containing animal fat with plant-source foods rich in MUFAs and PUFAs, such as vegetable oils, nuts, seeds, and pulses. Essential fatty acids—LA and ALA—were primarily obtained from such plant sources. In contrast, long-chain n-3 fatty acids, EPA and DHA, were obtained exclusively from animal-source foods, particularly fish and, to a lesser extent, eggs. Consequently, children and adults following a VGN diet, as well as other participants with low or no fish consumption, had negligible intakes of EPA and DHA. Current Finnish National Nutrition Recommendations advice a daily n-3 PUFA intake of 1 E%, and it is assumed that sufficient ALA intake supports adequate DHA status in vegans [37]. The recommendations include no guidance on long-chain n-3 fatty acid supplement use. However, the long-term health implications of chronically low intakes of DHA among VGN and some VGT populations remains unclear. This concern may be particularly relevant during pregnancy and early childhood, a critical period in which DHA plays a vital role in brain and retinal development [38].

PBDAs, the majority of which were fortified, contributed significantly to vitamin D and iodine intake in VGN and VGT diets—similar to milk and dairy products in OMN diets, particularly among children. In Finland, most fluid milk products are fortified with vitamin D [15], as natural sources are mainly limited to fatty fish, fish liver oil, and to a lesser extent, egg yolk [39]. National voluntary fortification practices include the addition of vitamin D3 to fluid milk products (1 µg/100 mL) and fat spreads (20 µg/100 g) [14]. The Finnish National Nutrition Recommendations advice the use of fortified PBDAs as alternatives for dairy products [37]. To bridge nutritional gaps between plant-based and animal-source foods, many PBDAs in Finland are voluntarily fortified with vitamin D2. Similar vitamin D intake observed across diet groups in children aligns with findings from our MIRA Helsinki pilot study [20], but contrasts with earlier studies reporting lower vitamin D intake among VGN groups [22, 40,41,42,43]. Overall, vitamin D intake in our study was higher than reported in other countries due to frequent consumption of fortified dairy and PBDA products and fat spreads [21, 22].

Milk and dairy were the main sources of iodine for children in the OMN and VGT groups. In contrast, for adults—who consumed less dairy—the main sources were the ‘spices and condiments’ group, and cereals. The Finnish National Nutrition Council recommends the use of iodized salt (iodine content of 25 µg/g) in households, food industry and food services [44], and iodine supplementation is advised for those following dairy-free diets [1]. Across all diet groups, the use of iodized salt in mixed dishes (as reflected in the ‘spices and condiments’ group) and by the food industry and bakeries (as reflected in the ‘cereals’ group) formed the basis of iodine intake. However, intake was lowest among children and adults in the VGN group. Our results suggest that broader implementation of iodine fortification in PBDAs warrants consideration to address lower intakes among those following VGN diets.

Milk and dairy products are naturally rich in several nutrients, including riboflavin and vitamin B12 [37]. In our study, fortified PBDAs emerged as a significant dietary source of these nutrients for VGT, and particularly VGN, participants. VGT and VGN participants exhibited lower intakes of vitamin B12 compared to their OMN peers. However, vitamin B12 fortification has likely increased over the past decade, as the intake among VGN Finnish adults measured in 2011 was lower than in the present study [45].

As in prior studies, VGN diet provided the highest folate and iron intake [20, 45,46,47]. Notably, folate intake in OMN group was particularly low, aligning with findings from the FinDiet 2017 study, which reported inadequate folate intake in nearly 40% of women and 30% of men [13]. Moreover, evidence remains inconclusive regarding whether the lower bioavailability of iron from plant sources contributes to suboptimal iron status or, conversely, is associated with certain health benefits [48].

Our dietary assessment methodology has several strengths. First, we employed the National Food Composition Database (Fineli®) and carried out extensive work to compile information on new recipes and food items. Second, collaboration with municipal food services enabled the inclusion of detailed information on recipes used in ECEC centers during the study. Third, we used the GIFT tool to standardize food group classification, enhancing the comparability and alignment of our findings with future research.

Our study does face certain limitations, such as the inherent challenges of dietary intake assessment methods related to accurate reporting by participants and ECEC staff. We mitigated these by using food picture books to improve the accuracy of portion size estimation and by collecting dietary data across two weekdays and one weekend day to capture day-to-day variability. Additionally, evaluating dietary intake remains challenging due to the frequent introduction of new food products and the laborious process of updating food composition databases. Finally, the families were recruited from the Helsinki capital area, and based on the caregivers’ educational levels, likely represented higher-than-average socioeconomic backgrounds, which may limit the generalizability of our results. However, individuals following a VGN diet are predominantly concentrated in larger cities, including Helsinki (personal communication, M. Simojoki, October 2025, https://doi.org/10.1093/eurpub/ckaf161.1366); therefore, our results likely provide a good overview of the VGN diet in Finland.