Introduction

Scientists assessed the risks/benefits of various scenarios for fortifying bread with folic acid in Portugal. Based on intake data from the ”National Food and Physical Activity Survey” (2015–2016), they analyzed various scenarios of different levels of fortification and the use of dietary supplements.

The objective of this study was to quantify the health impacts of hypothetical scenarios involving the consumption of folic acid-fortified bread and supplementation among the Portuguese population. The researchers used a risk-benefit analysis (RBA) and measured the health impacts in disability-adjusted life years (DALYs).

Scientific Background

fortification

Fortified foods are food products to which nutrients such as vitamins or minerals are added to improve their nutritional quality and address any deficiencies in the population. Previous studies suggest that mandatory food fortification is a sustainable approach to preventing nutritional deficiencies over time.

FOLATE/FOLIC ACID & importance

Folate is the natural form of vitamin B9 found in foods. It can be found in leafy green vegetables, legumes, fruits, and grains.

Folic acid is the synthetic form of folate. It can be found in supplements and fortified foods. Folate/folic acid is essential for DNA synthesis, red blood cell production, and nervous system development, and plays a crucial role during pregnancy in preventing neural tube defects.

DALY

DALY (disability-adjusted life year) is an increasingly common measure in public health used to assess the overall severity of a disease, expressed as the number of years lost due to the disease, disability, or premature death.

DALY = YLL + YLD
YLL stands for years of life lost due to premature death.
YLD stands for years lived with disability.

Materials & Methods

method

They used a risk-benefit analysis (RBA) approach and measured the health impacts in disability-adjusted life years (DALYs).

The scientists analyzed 15 different scenarios for folate/folic acid intake from various dietary sources, including whole foods, fortified foods, and dietary supplements.
As reported in the paper, The National Food and Physical Activity Survey 2015–2016 (IAN-AF 2015–2016) shows that folate/folic acid is the micronutrient for which the Portuguese population has the highest prevalence of intakes below the Average Requirement (AR), with 66% of women and 54% of men falling into this category.

risks/benefits analysis

Scientists say they conducted a comprehensive review of the literature, focusing on experimental evidence from official international organizations, such as the European Food Safety Authority (EFSA), 2023. They developed a probabilistic model and used Monte Carlo simulations with 10,000 iterations to account for variability and uncertainty.

Experimental Results

The data shown in the table are taken from the paper. All values represent estimated overall DALYs. The difference compared with the reference scenario (REF) indicates the additional healthy life years lost.

REF (Reference Scenario) is the baseline scenario, representing the usual dietary intake and dietary supplement consumption reported in the IAN-AF survey, without additional folic acid fortification of bread.

In the case of fortified bread + simple foods + dietary supplements, it was observed that as the concentration of folate/folic acid increases, health outcomes worsen—that is, the DALY index rises- but there is a point that needs to be clarified regarding the health effects.

A high intake of vitamin B9 in the form of folic acid may correct blood abnormalities caused by a B12 deficiency, without resolving the deficiency itself.

• Neural tube defects: Increased folate intake may reduce their incidence in newborns.

• Megaloblastic anemia: Increased folate intake may reduce the risk of developing this condition.

• Neurological damage: Higher folic acid exposure may increase the risk of neurological damage associated with vitamin B12 deficiency, particularly when the deficiency goes undiagnosed.

This explains the apparent contradiction in the results: although folic acid fortification can provide benefits by reducing the incidence of certain conditions, these benefits do not outweigh the potential neurological risks in the overall assessment. The neurological risk is particularly relevant for older adults, as vitamin B12 intake among Portuguese seniors is below recommended levels.

Folic acid can correct some haematological symptoms of vitamin B12 deficiency, potentially making the underlying deficiency more difficult to recognize while neurological damage progresses.

In Scenario D (420 μg/100 g of bread), the worst-case scenario analyzed, the number of healthy life years lost reaches 2,888 compared with REF.

1 μg (microgram) = 10^-6 g (0,000001g)

According to current official recommendations, the use of folic acid supplements by women of childbearing age would provide the greatest benefits to the general population.

The researchers also evaluated alternative supplementation strategies. The most beneficial scenario was Scenario E, which involved no mandatory bread fortification and the recommended folic acid supplementation of 400 μg/day for women of childbearing age. This approach resulted in an estimated 1,285 healthy life years saved compared with REF.

Limitations and Future Perspectives

LIMITATIONS

Using assumptions to obtain dose–response models, as is done in other RBAs, introduces uncertainties, and more studies are needed to develop more accurate dose–response data.

• Dose: the amount of a substance ingested.
• Response: the biological or health effect that occurs in response to that amount.

This introduces a certain degree of uncertainty, because the model may not perfectly represent the actual relationship between the amount of folic acid consumed and its health effects.

Vegetarians were not included in the analysis because there was insufficient data on the Portuguese population. This is important because they may be at greater risk of vitamin B12 deficiency.

There is an association between colorectal cancer and folate/folic acid intake, but this study did not take it into account due to the uncertainty surrounding this association.

Future Perspectives

According to the paper, future studies should focus on improving dose-response models while also taking into account ethical, socioeconomic, and sustainability considerations.

What Does the Paper Actually Show?

These findings suggest that targeted supplementation may be a more effective public health strategy than mandatory bread fortification, allowing folic acid intake to be increased in the population group that can benefit most, without unnecessarily increasing exposure across the entire population.

Bibliographic sources:

1. Oliveira, B.C., Nunes, T.P. & Pires, S.M. Risk–benefit assessment of different scenarios of bread fortification and supplementation with folic acid in Portugal. Food saf. and Risk 13, 48 (2026). DOI: https://doi.org/10.1186/s40550-026-00172-y

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