As consumers trade meat, fish and dairy for plant-forward substitutes, new modelling studies from The Netherlands show why smart swops, fortification and tailored guidance may be essential to keep plant-based diets nutritionally complete, reports News-Medical.net.
In their research recently published in the journal Nutrients, a group of scientists evaluated how replacing commonly consumed animal-based foods with plant-based alternatives affects protein, essential amino acid (EAA), vitamin and mineral intake across different age groups in the Dutch population.
Can switching to a more plant-based diet improve health without compromising essential nutrition? The question has gained importance across all ages, as plant-based eating offers health, environmental and ethical benefits.
Diets high in fruits, vegetables, legumes, nuts and whole grains lower the risk of developing chronic illness and also help reduce greenhouse gas emissions and resource consumption.
On the other hand, reducing or replacing major animal-based foods may lower protein, vitamin and mineral intake, particularly in children and older adults who have greater nutritional needs.
The researchers conducted a dietary simulation study using data from the Dutch National Food Consumption Survey (DNFCS) 2019-2021, a population-based cross-sectional survey co-ordinated by the National Institute for Public Health and the Environment (RIVM).
The study included 3 570 people across different age groups, sexes, backgrounds and regions. Dietary intake information was collected using two non-consecutive 24-hour dietary recalls, completed within two to six weeks, through the GloboDiet dietary assessment programme.
Nutrient intake was calculated using the Dutch food composition database.
The investigators modelled two dietary replacement scenarios. The first represented a nutritionally conscious transition in which commonly consumed animal-based foods were replaced with more nutritionally favourable plant-based alternatives.
The second represented a less nutritionally conscious transition using widely available plant-based substitutes with comparatively lower nutritional quality.
Major animal-based protein sources, including meat, poultry, fish, and dairy products, were replaced gram for gram with replacement products commonly available in the Dutch market, while mixed dishes and foods containing small amounts of animal-derived ingredients remained unchanged.
As a result, the scenarios represented a partial shift toward more plant-based eating, rather than a fully vegan or vegetarian diet.
The researchers then compared total protein, EAA, vitamin and mineral intake in the original and simulated diets with recommendations established by the World Health Organisation (WHO), the European Food Safety Authority (EFSA), the European Society for Clinical Nutrition and Metabolism (ESPEN), and other recognised authorities.
The simulation included dietary data from 3 570 participants across multiple age groups. In the original dietary data, average protein intake exceeded the WHO recommendations for nearly all age groups. However, adults aged 71-79 did not achieve the higher protein intake recommended by the ESPEN.
After replacing selected animal-based foods with plant-based alternatives, total protein intake declined in both dietary scenarios, with greater reductions in the less nutritionally conscious scenario.
Among females, protein intake fell below recommended levels in all age groups older than 18 in the nutritionally conscious scenario and in those aged 14-18 in the less conscious scenario.
Among males, intake fell below recommendations from 31-50 years onward in the nutritionally conscious scenario and from 19-30 onward in the less conscious scenario.
Although there was a marked increase in plant-based protein intake, particularly from legumes, it did not fully offset the reduction in animal-based protein intake.
The intake of EAAs also declined after dietary substitution. Nevertheless, average intakes of most EAAs remained above recommended levels across age groups. An important exception was the combined sulphur amino acid measure (methionine plus cysteine), which fell below recommended levels in older adults under both dietary scenarios.
Lysine remained close to recommended levels but did not fall below them. However, the authors noted that comparing methionine alone with a combined methionine-plus-cysteine requirement may have over-estimated inadequacy for this measure.
These data indicate that older adults may struggle to maintain protein intake during their transition to a more plant-based diet.
Intakes of vitamins A, B1 (thiamine), B2 (riboflavin), B3 (niacin), B6, and B12 generally declined after the age of nine, leaving many people below recommended intake levels.
However, folate intake increased slightly after dietary substitution, and males again met their recommended daily intake.
Folate intake remained below recommended levels among females. The original intake of vitamin D was already below recommended daily levels across all age groups, and after the substitution, it remained inadequate. On the other hand, vitamin E intake actually increased because the average amount of vitamin E in plant-based foods is greater than that in animal-based foods.
The modelled substitutions also affected mineral intake. Calcium, which was already low in several age groups before the change, decreased further due to the dietary transition, resulting in values below the recommended levels for all groups. Iron intake marginally increased due to greater non-heme iron intake, but it remained insufficient for children and reproductive-aged women.
Heme iron decreased, while non-heme iron slightly increased. Iodine, selenium, and zinc decreased in both cases; after substitution, zinc was inadequate for all age groups. Copper was found to have increased; potassium, manganese, and phosphorus remained mostly unchanged overall.
Conclusion
The researchers concluded that shifting toward more plant-based diets may reduce the intake of protein and several essential nutrients, particularly when substitutions are not nutritionally planned. Older adults and adolescents appeared to be the groups most vulnerable to nutritional inadequacies.
Although switching to a more plant-based diet can provide health and environmental benefits, careful dietary planning is needed to support adequate intake levels of EAAs, vitamins, and minerals.
Findings also indicated the potential value of nutrient-fortified foods, dietary guidance tailored to different age groups, and continued research evaluating protein quality, nutrient bioavailability, realistic consumption patterns, biomarker-based assessment of nutritional status, and the long-term effects of transitioning toward more plant-based dietary patterns.
Further research is needed to determine how dietary changes affect nutrient requirements across age groups.
Study details
Shifting to plant-based protein diets alters nutrient adequacy across age groups: A Dutch dietary modelling study
Jan de Vries, Cécile Singh-Povel, Lizette Oudhuis et al.
Published in Nutrients on 1 July 2026
Abstract
Background
Shifting toward more plant-based diets is promoted for health, environmental, and ethical reasons. However, the nutritional consequences of reducing animal-based foods, particularly across age groups with specific dietary needs, remain insufficiently understood.
Methods
In this simulation study, we used dietary intake data from 3570 participants in the Dutch National Food Consumption Survey (2019–2021) to evaluate how replacing animal-based foods with plant-based alternatives affects the intake of protein, essential amino acids (EAAs), vitamins, and minerals across different age groups. Two substitution scenarios were modelled: a nutritionally conscious and a less conscious plant-based dietary pattern.
Results
Total protein intake decreased in both scenarios, with the strongest reductions observed in elderly individuals (71–79 years). Vitamin intake, particularly B vitamins and vitamin A, declined in most age groups, and vitamin D remained chronically low. Mineral intake also decreased, notably for calcium, iron, iodine, selenium, and zinc, especially among women and adolescents.
Conclusions
These results underscore the importance of dietary planning and targeted fortification when promoting plant-based eating patterns. Future research should refine bioavailability estimates and evaluate the long-term health effects of such dietary transitions across life stages.
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