Folic acid in non-wholemeal common wheat flour from 13 December 2026: what changes, what the evidence says and what it means for supplements

From 13 December 2026, millers and importers must add 0.25 mg (250 micrograms) of folic acid to every 100 g of non-wholemeal common wheat flour, except where the regulations do not apply, including bread and flour brought into Northern Ireland from the EU or the European Economic Area. The next day, 14 December, the House of Commons is scheduled to debate a petition that asks the Government to stop the policy. The petition has more than 128,000 signatures.

The folic acid supplement advice for people who could become pregnant is a separate matter and has not been replaced by the flour rule. The NHS still recommends 400 micrograms a day as a supplement, and a higher prescribed dose for some groups.

The short answer: the rule is aimed at neural tube defects such as spina bifida, which the Government says affect about 1,000 UK pregnancies a year, and it projects that fortification will prevent around 200 of them annually. The Scientific Advisory Committee on Nutrition (SACN) has recommended fortification since 2006 and reaffirmed it in 2017. Criticisms in the petition and the consultation include consent and choice, and the clinical concerns set out below. How far the safeguards SACN attached to its advice have been put in place is taken up below. Neither side's headline claim is the whole picture.

What changes on 13 December

• Folic acid (pteroylmonoglutamic acid), 0.250 mg per 100 g, must be added to non-wholemeal common wheat flour, regardless of the folate the flour contains naturally.
• The same change raises the minimum iron to 2.10 mg (from 1.65 mg) and the minimum niacin to 2.40 mg (from 1.60 mg) per 100 g. Calcium carbonate rises to 300 to 455 mg (from 235 to 390 mg) per 100 g, except that it need not be added to self-raising flour with a calcium content of 0.2% or higher, or to wheat malt flour. Thiamin stays at least 0.24 mg.
• Wholemeal flour is exempt. So is flour from a small mill, meaning a production site whose maximum annual capacity is 500 metric tonnes of flour and which has produced less than 500 metric tonnes of flour in each of the last three calendar years, and flour produced to make communion wafers, matzos, gluten or starch.
• Flour that met the old rules and was labelled or placed on the market before 13 December can stay on sale afterwards.
• Imported products that contain flour as one ingredient among several are outside the requirement.
• Added folic acid must appear in the ingredients list, including when fortified flour is an ingredient in another food.

The GOV.UK guidance covers England, Scotland, Wales and Northern Ireland, under separate regulations in each. Local authorities enforce them.

Why the Government is doing it

Neural tube defects arise in the first weeks of pregnancy, often before a woman knows she is pregnant. The 2019 consultation response says there is strong scientific evidence that increasing dietary folate intake and blood folate concentration in women who can, or plan to, become pregnant can help reduce the risk and the number of pregnancies affected by neural tube defects. UK advice has long been to take a 400 microgram folic acid supplement before conception and until the twelfth week of pregnancy. The Government's response to the petition says almost half of UK pregnancies are unplanned, that uptake of the 400 microgram supplement advice remains suboptimal, particularly among younger women and those from lower socio-economic backgrounds, and that public health campaigns to promote supplementation, as well as voluntary fortification by manufacturers, have had limited success.

The foundation of the supplement advice is the Medical Research Council Vitamin Study, published in The Lancet in 1991. It randomised 1,817 women at high risk because of a previous affected pregnancy to folic acid, other vitamins, both or neither. Of 1,195 pregnancies with a known outcome, 27 had a neural tube defect: 6 in the folic acid groups and 21 in the other two groups, a 72% protective effect (relative risk 0.28, 95% confidence interval 0.12 to 0.71). That trial gave a supplement to high-risk women. It did not involve flour.

The estimate of UK pregnancies prevented comes from modelling. The impact assessment behind the 2019 consultation found that an increase of 60 to 100 micrograms of folic acid a day was required to see significant benefits in reducing neural tube defects. SACN reports significant reductions in neural tube defects among live births in countries with mandatory folic acid fortification. The consultation response reports that mandatory fortification has reduced rates of neural tube defects in other countries. The consultation response cites National Diet and Nutrition Survey data for 2015 to 2016, analysed in the impact assessment, which found that 92% of UK adults consume products containing non-wholemeal wheat flour, a higher share than for any other flour type in that analysis. Governments kept the requirement to that flour because it is already fortified and widely eaten. The Government's petition response puts the projected benefit at around 200 affected pregnancies prevented a year, about 20% of UK cases.

What the evidence says about the concerns

SACN reviewed the potential harms in 2017, at the request of Food Standards Scotland. It concluded that the evidence on potential adverse effects of folic acid published since its 2006 and 2009 reports "does not provide a substantial basis for changing" its recommendation for mandatory fortification. On the specific worries raised by petitioners and by respondents to the consultation:

• Vitamin B12 deficiency. High-dose folic acid can relieve the anaemia of B12 deficiency, which could delay its diagnosis and may lead to irreversible neurological damage. SACN noted that the evidence for this comes mainly from interventions above 1 mg a day, that no systematic review has evaluated the risk in adults, and that B12 deficiency prevalence did not rise after mandatory fortification in the USA. The 2019 consultation response says there is no evidence that folic acid can mask the diagnosis of vitamin B12 deficiency at doses up to 1 mg a day in the short term.
• Cancer. SACN found the evidence inconsistent. Randomised trials of folic acid supplements show no effect on overall, breast, prostate or colorectal cancer risk, and the overall data do not suggest a detrimental effect. SACN also notes that statistical power is generally low, particularly in the trials. For prostate cancer, blood-folate studies and genetic studies both suggest higher risk at higher folate, while trials show no effect. For colorectal cancer, studies of folate intake suggest a protective association above about 400 micrograms a day, while genetic studies suggest higher blood folate is associated with higher risk. SACN says it is difficult to draw firm conclusions.
• Unmetabolised folic acid in the blood. SACN found no clear dose-response relationship between folic acid intake and its appearance in the circulation. It makes up 1 to 3% of total folate regardless of age or intake. SACN says these observations question the idea that this shows intake above the body's short-term capacity to process folic acid. SACN's 2006 report had found insufficient data to assess long-term effects of unmetabolised folic acid in the circulation.
• Medicines. The consultation response notes that the BNF lists interactions between folic acid supplements and some epilepsy and cancer medicines, and that its interaction information covers supplements, not fortified foods. The consultation response adds that SACN's 2006 report, based on a small number of studies of phenytoin, concluded that the dose provided by fortification is unlikely to have an adverse impact on anticonvulsant drug metabolism. The consultation response recommends that people taking these medicines speak to their GP or another healthcare professional if they are concerned about an interaction.
• Choice. This is the petition's central objection: it calls folic acid a medicine, not a food, and says it is unethical to "mass medicate the entire population without their knowledge or consent". The Government's reply is that fortification is an evidenced public health measure, not a medical intervention, that added folic acid must be labelled, and that people can avoid fortified flour by choosing wholemeal flour, gluten-free products, or other flours such as soya or spelt. The petition notes that some wholemeal and gluten-free products already add folic acid voluntarily, which makes avoidance harder.

The weak spots both sides can point to

SACN's advice came with conditions. It said mandatory fortification should be introduced only alongside restrictions on voluntary fortification, clear guidance on folic acid supplements, and monitoring of intakes and blood folate so that the share of people above the upper intake level does not rise. The 2019 consultation response said the need to limit voluntary fortification of other products would be assessed later, and the Government has since said it is exploring how to evaluate the policy's impact. The impact assessment cited in the consultation response estimated that 0.417% of the population currently exceed the tolerable upper level for folic acid, which is 1 mg a day.

The size of the benefit is a projection. Whether around 200 pregnancies a year are prevented will only be known from monitoring after the rule starts. The petition's point about consent is a values question that evidence cannot settle. The Government answers the consent point by calling fortification an evidenced public health measure, not a medical intervention, and by pointing to labelling and to flour that is outside the requirement. Added folic acid has to be named in the ingredients list. A label does not show whether flour came from a small mill or from an imported multi-ingredient product.

What it means for people who take folic acid supplements

• NHS advice for anyone trying to get pregnant, or newly pregnant, is 400 micrograms of folic acid a day, ideally from three months before conception and for the first 12 weeks of pregnancy. The NHS says it is difficult to get that amount from food alone.
• The NHS recommends a higher dose of 5 mg a day, which a GP can prescribe, if you are planning a pregnancy or are less than 12 weeks pregnant and you or the baby's father has a neural tube defect, you or the baby's father has a relative with a neural tube defect, you have had a previous pregnancy affected by a neural tube defect, you have diabetes, you have a blood condition such as sickle cell anaemia or thalassaemia, or you take medicine for epilepsy or HIV.
• The NHS medicines page says the amount of folic acid added to food is much lower than the amount in medicines or supplements, and that this page does not cover folic acid added to food. The flour rule is a composition level of 250 micrograms per 100 g of flour. The NHS pregnancy supplement is 400 micrograms a day. Those are not the same kind of amount.
• The same NHS page lists reasons folic acid tablets or liquid may not suit someone, including vitamin B12 deficiency anaemia or pernicious anaemia, a coronary stent and cancer. That page is about supplements and medicines. It states that it does not cover folic acid added to food.

The NHS medicines page says folic acid tablets or liquid may not suit some people, and that the page does not cover folic acid added to food. The Government's petition response says people who may need to avoid folic acid should seek advice from a healthcare professional. Added folic acid has to be named in the ingredients list. The consultation response says the advice to take a folic acid supplement before and in early pregnancy remains in place alongside the flour rule. A multivitamin can contain folic acid. If you are pregnant, the NHS says to check with a doctor or pharmacist before taking one. Before taking folic acid tablets or liquid, the NHS says to tell a doctor about any other medicines, herbal remedies, vitamins or supplements.

UK rules

Folic acid in flour is a food composition requirement under the Bread and Flour Regulations. It applies to non-wholemeal common wheat flour that is milled or imported, not to supplements. Supplements containing folic acid remain separate products. NHS information describes folic acid taken as a medicine or supplement, and reports of suspected side effects from a medicine can be made through the MHRA Yellow Card scheme.

FAQ

Will all bread in the UK contain folic acid after 13 December?

No. The requirement applies to non-wholemeal common wheat flour. Wholemeal flour, flour from small mills, and flours that are not common wheat, such as soya or spelt, are not covered. Flour that met the previous rules and was labelled or placed on the market before 13 December can stay on sale. Imported products that contain flour as one ingredient among several are outside the requirement, whether sold as a finished product or prepared further.

What happens at the 14 December debate?

The debate is scheduled for 14 December 2026, the day after the requirement starts, and the UK Parliament YouTube channel will show it. A debate does not suspend the requirement. The requirement is set out in regulations that have already been made.

Can I avoid fortified flour?

Yes, to a large extent. Added folic acid must be listed in the ingredients, and wholemeal flour and other flours are exempt. The petition points out that some wholemeal and gluten-free products add folic acid voluntarily, so reading the label matters.

Does this replace the advice to take a folic acid supplement before pregnancy?

No. The NHS still advises 400 micrograms a day as a supplement before conception and for the first 12 weeks of pregnancy. The consultation response describes fortification as a way to reach women whose pregnancies are unplanned and women who do not take folic acid supplements before pregnancy. Speak to a midwife, GP or pharmacist about your own dose.