Folic acid in flour: who should take care - Marriage's organic stoneground wholemeal bread flour with proving baskets

Folic Acid in Flour: Who Should Take Care and Why Some Choose Unfortified Flour

November 14, 2026

From 13 December 2026, folic acid must be added to most white and brown wheat flour sold in the UK, which means it will also be in most shop-bought bread, cakes and biscuits. For the majority of people this is a small, safe addition designed to prevent serious birth defects. But folic acid is not a neutral ingredient for everyone, and some people will want to keep an eye on how much they take in. This article explains the official view, the questions some experts still raise, who may want to take special care, and why some people simply prefer unfortified flour.

This article is general information, not medical advice. If you have a health condition or take regular medicines, speak to your GP or pharmacist before changing your diet or supplements.

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The Official View

Folic acid is the synthetic form of folate, a B vitamin. Taken before conception and in early pregnancy, it lowers the risk of neural tube defects such as spina bifida. Because many pregnancies are unplanned, the government decided to add it to flour at 0.25mg per 100g, and estimates this will prevent around 200 cases a year.

The government's advisers on nutrition, SACN, reviewed the evidence in 2017. They kept the long-standing upper level of 1mg of folic acid a day for adults and noted that in the USA, where flour has been fortified since 1998, vitamin B12 deficiency did not increase after fortification began. In 2023 the European Food Safety Authority (EFSA) carried out a fresh review of the evidence and also kept the 1mg upper level for adults. The NHS still advises anyone planning a pregnancy to take a 400 microgram folic acid supplement: fortified flour does not replace it.

Why Some Experts Urge Caution

The official reviews also list open questions. These are the main ones you will see discussed:

Masking vitamin B12 deficiency. Folic acid can correct the anaemia caused by a lack of vitamin B12, while the nerve damage that B12 deficiency also causes carries on unnoticed. This is the reason the 1mg upper level exists, according to the Committee on Toxicity. The evidence for masking comes mostly from intakes above 1mg a day; at lower intakes it is limited and mixed.

Unmetabolised folic acid. Unlike natural folate, folic acid has to be converted in the body. At higher intakes some of it circulates in the blood unchanged. SACN concluded there is not enough data to say whether this has any effect on health.

Cancer. SACN found the evidence on folic acid and cancer inconclusive. For bowel cancer, studies of folate intake point to a protective link; for prostate cancer, some studies suggest higher folate levels may be linked to higher risk. SACN called for more research.

Older people with low B12. Some studies have linked high folate together with low B12 to poorer memory and thinking in older adults. The evidence is inconsistent and mostly based on intakes above 1mg a day.

A whole-population approach. Organisations such as the Soil Association have argued that the priority should be healthy diets, that adverse effects should be monitored, and that people should keep a choice. Fortification reaches everyone who eats white or brown bread, not only the women it is designed to help.

What Newer Research Says (2018 to 2026)

The UK committees last reviewed folic acid safety in 2017, and research has continued since. These are the most relevant newer studies, with what they can and cannot tell us. Most are observational or animal studies, which can show a link but not prove cause and effect.

Upper limit re-checked (2023). EFSA's independent review kept the 1mg daily limit for adults. Its main concern remains people with low vitamin B12, in whom high folic acid may let nerve symptoms progress. It found the evidence too weak to conclude that folate causes bowel or prostate cancer or cognitive decline, and said the limit is unlikely to be exceeded except by regular users of high-dose supplements.
Older adults with low B12 (2020). A US study of 2,420 people aged 60 and over found that, among those with low B12, high folate was linked to roughly twice the odds of low scores on two memory and thinking tests. The authors called the link potential but inconsistent: it appeared on some tests only.
Pregnancy and autism (2020 to 2021). In the Boston Birth Cohort, babies with the highest levels of unmetabolised folic acid in cord blood had about twice the odds of a later autism diagnosis; the researchers stressed this was hypothesis-generating. On the other hand, a 2021 meta-analysis of 10 studies found that folic acid taken in early pregnancy was linked to a lower autism risk, with no extra benefit above 400 to 800 micrograms a day. Together they suggest a Goldilocks effect: enough, but not far more than recommended.
Unmetabolised folic acid (2023). A 2023 review noted that unmetabolised folic acid is found in more than 95% of people in the USA, where flour has long been fortified, and concluded that evidence it causes harm is still inconclusive. Animal studies give a stronger signal than human ones.
DNA changes in animals (2023). A study in mice found that both too little and too much folic acid increased new DNA mutations. The authors called for human studies before drawing conclusions.
Inflammation and older adults (2025). A 2025 review argued that high folic acid intake may promote inflammation and harm nerve cells, mainly based on mouse studies, and highlighted older adults with low B12 and people with MTHFR variants as groups to watch.
Cancer (2026). A large umbrella review of folate and cancer found the evidence generally limited. It reported a possible link between higher folate and prostate cancer, but rated that evidence as weak and called for better studies.

Our take: newer research has not shown harm from the amount added to UK flour, but it keeps pointing to the same open questions: people with low vitamin B12, very high intakes from supplements, and how much is too much in pregnancy. If any of these apply to you, choosing unfortified flour is a reasonable way to keep your total intake in check, alongside advice from your GP.

It Adds Up: How Much Folic Acid Could You Be Eating?

One slice of bread will not take anyone near the limit. But fortified flour is in far more than bread: pizza, wraps, pastries, cakes, biscuits, crumpets, fresh pasta made with wheat flour, sauces thickened with flour and many ready meals. UK flour is fortified at 250 micrograms (0.25mg) per 100g, and the Health Food Manufacturers' Association estimates around 60 micrograms in a slice of bread. The legal level is set for the flour itself, before it is baked, while the upper limit counts what you actually eat, so the table shows both. Here is an example of a high-flour day for an adult:

Food on a high-flour day	Fortified flour	Added to the flour	Roughly eaten after baking
4 slices of bread	about 100g	250 micrograms	about 190 micrograms
Half a 12-inch pizza	about 100g	250 micrograms	about 190 micrograms
A pastry, or 2 biscuits and a slice of cake	about 40g	100 micrograms	about 75 micrograms
Total from flour		600 micrograms	about 450 micrograms
Plus a standard 400 microgram supplement (not baked)		1,000 micrograms	about 850 micrograms

Baking destroys some folic acid: one study measured losses of about 22% to 31% in bread, so the last column assumes roughly a quarter is lost. Losses in pizza, cakes and biscuits may be different. A supplement is not baked, so all 400 micrograms count. On a day like this, a fortified breakfast cereal or a little more bread or pizza can bring an adult close to the 1mg upper level.

What about pasta? Most dried pasta is made from durum wheat semolina, and durum is not covered by the rules, so it has no added folic acid. Wholewheat, spelt and gluten-free pastas are exempt too, and imported products made with flour, such as fresh pasta made in Italy, are not covered either. The exception is fresh pasta made in the UK from white wheat flour (look for "00" or "wheat flour" on the label): a 125g portion contains roughly 80g of flour, or about 200 micrograms of folic acid added to the flour. Pasta holds on to folic acid well: one test found about 18% was lost when the dough was made and only around 4% during cooking, so expect around 160 micrograms on your plate.

The same applies to homemade pasta: a "pasta flour" blend of white wheat and durum is fortified, while pure durum wheat semolina or Caputo Durum Wheat Semola is not. If you buy dried pasta, Organic Italian Spaghetti, Organic White Penne, Organic Spelt Spaghetti and Organic Wholemeal Spelt Fusilli all have nothing added.

Don't forget your multivitamin. Folic acid is a standard ingredient in everyday multivitamins, including the 50+ formulas many older people take every day. Wellman 50+, for example, contains 200 micrograms per tablet and Centrum Advance 50+ contains 300 micrograms. Swap the pregnancy supplement in the table for a 300 microgram multivitamin and the same high-flour day still comes to around 750 micrograms after baking, before any fortified cereal. Older adults are also the group most likely to have low vitamin B12, so it is worth checking the label of any multivitamin you take and mentioning it to your GP or pharmacist if you are unsure.

Children reach their limit much sooner. Government-funded modelling, quoted in the Food Standards Agency risk assessment, estimated that about 0.6% of the whole population would go over their upper level, but the highest share, about 4.4%, was among toddlers aged 1.5 to 3. Their limit is just 200 micrograms a day, roughly the amount in four to five slices of fortified bread once baking losses are taken into account.

That is why the total matters more than any single food. If you eat a lot of bread, pizza and baked goods, take supplements or are feeding a young child, swapping some of that flour for wholemeal, spelt, rye or another exempt flour is the simplest way to keep your intake in check.

Supplements: The Targeted Alternative for Pregnancy

Many critics of fortification argue that supplements are the better way to protect babies: the people who need extra folate take a measured dose before and during early pregnancy, and everyone else keeps a choice about what they eat. Supplements do work when they are taken. The landmark Medical Research Council Vitamin Study, published in 1991, showed that folic acid taken before conception and in early pregnancy prevents most neural tube defects, and the NHS recommends 400 micrograms a day from before conception until week 12.

The problem the government points to is uptake. In England, fewer than 1 in 5 women now take folic acid before pregnancy, with even lower rates in the most deprived areas, and around half of UK pregnancies are unplanned. That gap is the main reason fortification was chosen, even though it reaches the whole population.

Folic acid or folate? Some supplements use methylfolate (5-MTHF), the active form of folate, or natural folate from food sources instead of synthetic folic acid. A 2023 randomised trial in pregnant women found methylfolate kept folate levels as well as folic acid while leaving less unmetabolised folic acid in the blood. Folic acid is still the form proven in large trials to prevent neural tube defects and the one the NHS recommends, so talk to your GP, midwife or pharmacist before choosing, and never stop or swap a prescribed higher dose without advice.

If you are planning a pregnancy, a measured supplement such as Natures Aid Folic Acid 400ug gives you the recommended dose, and choosing unfortified flour helps keep the rest of your intake predictable. For those who prefer folate without synthetic folic acid, Together Health Natural Folate is made from spinach.

Who May Want to Take Special Care

If you are in one of these groups, it is worth knowing your total folic acid intake from supplements, fortified cereals and now flour, and discussing it with your GP or pharmacist:

People with low vitamin B12 or at risk of it: older adults, whose absorption of B12 falls with age; vegans and vegetarians who do not take a B12 supplement or B12-fortified foods; people with pernicious anaemia; and people taking metformin long term, which can lower B12. A simple blood test can check your B12 level.
Young children: the upper level for ages 1 to 3 is only 200 micrograms a day, and modelling suggests toddlers are the group most likely to go over it. If your child also has fortified cereals or a children's multivitamin, check the labels.
People taking medicines that interact with folic acid. The NHS lists epilepsy medicines such as phenytoin, phenobarbital and primidone, the antibiotics chloramphenicol and co-trimoxazole, sulfasalazine and lithium. These warnings are about folic acid tablets; flour adds a much smaller amount, but your pharmacist can tell you whether it matters for you.
People already taking folic acid supplements or a daily multivitamin, especially a prescribed high dose. Never stop prescribed folic acid without speaking to your doctor, but do mention that you eat bread and other fortified foods.
People with cancer. The NHS advises checking with a doctor before taking folic acid tablets if you have cancer, so it is reasonable to ask your care team about dietary folic acid too.
People told they carry an MTHFR gene variant. The variant makes converting folic acid less efficient but does not stop it, and research suggests folic acid still protects against neural tube defects in carriers. Some people still prefer foods without it; your GP can advise.

Why Some People Choose Unfortified Flour

For many shoppers the choice is not about fear of folic acid but about control and preference:

Keeping track of total intake when you already take supplements or eat fortified cereals
Simple, single-ingredient food: flour that is just milled grain, with nothing added
Natural folate instead of synthetic folic acid: wholegrains, pulses and leafy greens all provide folate naturally
Organic and traditional baking principles: some bakers prefer flour exactly as it comes from the mill
Personal or medical advice to keep folic acid intake modest

How to Avoid Fortified Flour and Bread

Our guide Folic Acid in UK Flour: Which Flours Are Affected and Which Are Exempt explains in detail which flours are covered and how to read the label. In short:

Choose exempt flours: wholemeal wheat such as Organic 100% Strong Wholemeal Bread Flour or Marriage's Golden Wholegrain Bread Flour, spelt such as Organic White Spelt Flour, rye such as Organic White Rye Flour, ancient grains such as Organic Einkorn Wholemeal Flour, or gluten-free flours
Mill your own: home-milled Organic Wheat Grain gives fresh wholemeal flour with nothing added
Check bread labels: shop-bought bread made with white or brown flour will list folic acid in its ingredients. Bread made only from wholemeal, spelt or rye flour does not need it, but many rye and seeded loaves also contain white flour, so read the ingredients
Bake at home or ask your baker which flour they use: small mills producing under 500 tonnes a year are also exempt

FAQs

Is fortified flour dangerous?
For most people, no. UK advisers and, in 2023, the European Food Safety Authority judged the 1mg daily upper level for folic acid to be appropriate, and EFSA found it unlikely to be exceeded except by regular users of high-dose supplements. The concerns above mainly apply to high intakes and to people with low vitamin B12.

Should I stop taking my folic acid supplement?
No, not without advice. The NHS recommends a 400 microgram supplement for anyone planning a pregnancy and in early pregnancy, and prescribed folic acid should only be changed by your doctor.

Is folate the same as folic acid?
Folate is the form found naturally in foods such as leafy greens, pulses and wholegrains. Folic acid is the synthetic form used in supplements and added to flour.

Will bread from the supermarket contain folic acid?
Most bread made with white or brown wheat flour will. Bread made only from wholemeal, spelt, rye or gluten-free flour should not, but many loaves mix in some white flour, so always check the ingredients.

How do I know if my vitamin B12 is low?
Your GP can arrange a simple blood test. This is worth asking about if you are older, vegan or vegetarian, have pernicious anaemia or take metformin.

Research Referenced

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