Biscuit: the research is mostly about what a biscuit can carry

Biscuit is a category more than a food, and our table holds nine of them, from a dry mix to refrigerated dough. The strongest evidence we hold treats the biscuit as a delivery vehicle. Across 49 randomised trials of vitamin D fortified foods, of which 5 used bread or savoury biscuits, the carriers raised 25-hydroxyvitamin D by 9 to 35 nmol/L, and plant-based and animal-based vehicles came out level at 15.2 against 15.9 nmol/L (P = 0.48). Five trials is a thin arm, those were savoury biscuits rather than a sweet one, and heterogeneity ran from 33 to 99 percent, so that is a fact about a fortificant and its carrier and not about the biscuits on a shelf. The most striking trial here works the same way. In 457 lead-exposed Moroccan children fed fortified wheat-flour biscuits at school six days a week for 28 weeks, blood lead fell from 4.3 micrograms per dL to 2.9 (95% CI 2.7 to 3.0) with iron as NaFeEDTA, against 3.7 on placebo. Cognitive test scores did not move, and these were children who already had lead exposure and low iron status in one country, so the finding is about lead absorption.

The numbers, per 100 g

What a real portion looks like

• Printing stripes on the pack to mark one portion did not cut how much people ate overall. In 674 households sent gift packs of chocolate biscuits, the number eating more than the recommended portion fell by 26%, and only where the recipient was female. — two preregistered randomised trials, 253 people in a laboratory and 674 households receiving chocolate biscuits at home, consumption measured without the eaters knowing (n = 927) Evidence B source
  The preregistered main effect of the visual cue was not significant, with a 26% fall in households eating more than the recommended portion when the recipient was female, and a 33% fall in men eating a whole can of crisps in the laboratory study

What your body absorbs

• School biscuits made with iron and EDTA pulled blood lead down in 457 lead-exposed Moroccan children over 28 weeks, from 4.3 to 2.9 micrograms per dL on the combined fortificant against 3.7 on placebo. — 457 lead-exposed Moroccan children eating fortified wheat-flour biscuits at school 6 days a week for 28 weeks, in a 2 by 2 factorial double-blind placebo-controlled design (n = 457) Evidence B source
  Blood lead 4.3 micrograms per dL at baseline, and at 28 weeks 2.9 (95% CI 2.7 to 3.0) with iron as NaFeEDTA, 3.3 with ferrous sulfate, 3.3 with EDTA alone and 3.7 with placebo, with no benefit on cognitive test scores

What it does to your health

• Swapping the daily biscuit for almonds for a whole year did not change body weight: in 136 habitual snackers the two groups ended within a kilogram of where they started. — 136 non-obese adults who habitually snacked on discretionary foods, randomised to almonds or biscuits daily for 1 year, each snack giving 10% of energy needs or 1030 kJ (n = 136) Evidence B source
  Body weight 67.1 to 69.5 kg on almonds against 66.3 to 66.3 kg on biscuits, P = 0.275, with no significant difference in body composition, and higher fibre, vitamin E, magnesium and zinc but lower sugar in the almond group
• Pooling 49 randomised trials of vitamin D fortified foods, of which 5 used bread or savoury biscuits, the fortified vehicles raised blood 25-hydroxyvitamin D by roughly 9 to 35 nmol/L. Plant-based and animal-based vehicles came out the same overall, at 15.2 against 15.9 nmol/L. — 49 randomised controlled trials of vitamin D fortified foods, including 5 trials using bread or savoury biscuits, alongside orange juice, cheese, yogurt, milk, eggs and oils (n = 49 trials) Evidence A source
  Weighted mean difference in 25-hydroxyvitamin D of about 9 to 35 nmol/L depending on the vehicle, all significant except UV-treated mushrooms (P = 0.06), and no difference between plant-based and animal-based vehicles (15.2 against 15.9 nmol/L, P = 0.48)

Safety, limits and interactions

• Baking sugar and flour hot enough to brown them makes acrylamide, and EU law sets a benchmark level of 350 micrograms per kg for biscuits and wafers, against 800 for gingerbread and 300 for other fine bakery wares. — manufacturers and food business operators in the European Union, a regulatory benchmark rather than a study population Evidence E source
  Benchmark level 350 micrograms per kg for biscuits and wafers, 400 for non-potato crackers, 350 for crispbread, 800 for gingerbread and 300 for similar fine bakery wares
• A 5.5-year-old boy who ate nothing but milk and biscuits for over three years was investigated for cancer before blood work showed scurvy at 3 micromol/L. — one boy aged 5.5 years with language delay and severe selective eating, presenting with limping and bleeding gums (n = 1) Evidence D source
  Vitamin C 3 micromol/L against a normal range of 26 to 84, bone marrow aspiration and maxillary biopsy both negative, walking restored within 48 hours of intravenous vitamin C at 250 mg daily

What people believe that the data does not support

• Telling teenagers how far they would have to walk off a biscuit shifted the tills a little: across about 99000 purchases in 11 English secondary schools, cake and biscuit sales fell by around 11 items per week per 100 students. — 11 secondary schools in England, adolescents aged 11 and over, about 99000 purchase transactions of cakes and biscuits over up to six weeks of labelling (n = 11 schools) Evidence B source
  Reduction of about 11 cake or biscuit items per week per 100 students, adjusted mean difference -0.112 (95% CI -0.179 to -0.045), P = 0.005

What is still unknown

• Nobody has measured how much biscuit a typical reader eats, and the closest pooled number comes from 67093 Iranian children aged 4 to 12, where biscuits and cakes ran at 3.33 servings a day, behind sugars and sweets at 8.01. — 10 studies pooling 67093 Iranian children aged 4 to 12, consumption of processed foods converted to servings per day (n = 67093) Evidence C source
  Sugars and sweets 8.01 servings a day, oils 5.58, biscuits and cakes 3.33

The bottom line

Trading one snack for another will not move the scales by itself. Each snack gave 10 percent of energy needs, about 1030 kJ. When 136 adults who habitually snacked ate either almonds or biscuits daily for a year, body weight went from 67.1 to 69.5 kg on almonds and from 66.3 to 66.3 kg on biscuits (P = 0.275). What did change was the rest of the diet, with more fibre, vitamin E, magnesium and zinc and less sugar in the almond group. It was an even calorie swap in people who were not obese to begin with, so read it as the snack choice shifting diet quality while the scales stay where they are. Two trials tried to make people eat fewer biscuits and mostly did not manage it. Stripes printed on the pack to mark one portion missed their preregistered main effect in both studies. The reduction that did appear was a subgroup one: among 674 households sent gift packs of chocolate biscuits, the number eating more than the recommended portion fell by 26 percent when the recipient was female. The authors ask for more work before anyone leans on that, and both studies found people unsure what a serving size even means. Labelling the shelf did a little better. In 11 English secondary schools, telling students how much walking a cake or biscuit would cost them cut purchases by about 11 items per week per 100 students (adjusted mean difference -0.112, 95% CI -0.179 to -0.045). The labelling ran six weeks at most, 11 of 18 randomised schools took part, and a purchase counted at a till is not a biscuit eaten. How much biscuit you personally eat, nobody has measured. The closest pooled figure we hold comes from 10 surveys of 67093 Iranian children aged 4 to 12, where biscuits and cakes ran at 3.33 servings a day, behind sugars and sweets at 8.01. Intake there was self-reported and servings were converted between studies, so the number describes those children and nobody else. Two cautions, both narrow. Browning flour and sugar produces acrylamide, and Commission Regulation (EU) 2017/2158 sets a benchmark level of 350 micrograms per kg for biscuits and wafers, 800 for gingerbread and 300 for similar fine bakery wares. A benchmark level is a performance indicator for checking that mitigation measures work, so a product above it is not automatically unlawful. The second caution belongs to a diet rather than to a biscuit. A 5.5-year-old boy who ate only pasteurised milk and biscuits for more than three years was worked up for cancer before blood tests found vitamin C at 3 micromol/L against a normal range of 26 to 84. He walked again within 48 hours of intravenous vitamin C at 250 mg a day, and this is one child with severe selective eating rather than a warning about the food. Past those two we hold nothing. There is no card here on biscuits in pregnancy, in children more generally, or alongside a medicine, because the interaction layer behind these pages is organised by nutrient and a baked good has no entry in it. The nine USDA records are mixes, doughs and recipes with no Foundation analysis among them, so we can give you no measured spread between samples and no retention figure for what baking does.

Sources

1. bisc-r2-06 · randomised controlled trial
   Study 2 monitored household consumption of chocolate biscuits (cookies) sent to family homes in gift packs. Again, the main effect was nonsignificant but there was significant subgroup variation...The effect size was again large: the number of households eating more than the recommended portion fell by 26%.
   Ann Behav Med, 2021 · checked 2026-09-24
2. bisc-r2-04 · randomised controlled trial
   The adjusted geometric mean BPb concentration at baseline was 4.3 μg/dL (95% CI: 4.2, 4.3 μg/dL), and at endpoint these values were 3.3 μg/dL (95% CI: 3.1, 3.5 μg/dL) for FeSO4, 2.9 μg/dL (95% CI: 2.7, 3.0 μg/dL) for NaFeEDTA, 3.3 μg/dL (95% CI: 3.1, 3.5 μg/dL) for EDTA, and 3.7 μg/dL (95% CI: 3.5, 3.9 μg/dL) for placebo.
   Am J Clin Nutr, 2016 · checked 2026-09-24
3. bisc-r2-01 · randomised controlled trial
   The difference in changes for body weight from baseline to 12 mo was not statistically significant (geometric means: 67.1 and 69.5 kg for almonds and 66.3 and 66.3 kg for biscuits, P = 0.275).
   Am J Clin Nutr, 2023 · checked 2026-09-24
4. bisc-r2-03 · systematic review and meta-analysis
   The searches identified 49 papers which described suitable RCTs using vitamin D-fortified bread/savoury biscuits (n = 5), orange juice (n = 5), UV-mushrooms (n = 8), cheese (n = 3), yogurt (n = 5), fluid milk (n = 13), powdered milk (n = 5), eggs (n = 2), edible oils (n = 4), or breakfast cereal (n = 1)...Sub-group analysis on the basis of whether the food vehicles were from plant-based or animal-based origin showed no significant difference in WMD (15.2 versus 15.9 nmol/L, respectively; P = 0.48).
   J Steroid Biochem Mol Biol, 2024 · checked 2026-09-24
5. bisc-r2-02 · European Union regulation
   performance indicators used to verify the effectiveness of the mitigation measures and are based on experience and occurrence for broad food categories
   Commission Regulation (EU) 2017/2158, Annex IV · checked 2026-09-24
6. bisc-r2-05 · case report
   A detailed dietary history revealed an extremely restricted diet consisting solely of pasteurized milk and biscuits for over three years. The vitamin C level was severely low at 3 µmol/L (normal range: 26-84 µmol/L), confirming the diagnosis of scurvy.
   Cureus, 2026 · checked 2026-09-24
7. bisc-r2-07 · cluster randomised controlled trial
   There was a reduction in cake/biscuit purchases in intervention schools versus comparators of ~ 11 items per week per 100 students at follow-up (adjusted mean difference = -0.112, 95% CI [-0.179 to -0.045], p = 0.005).
   Int J Behav Nutr Phys Act, 2025 · checked 2026-09-24
8. bisc-r2-08 · systematic review and meta-analysis of observational surveys
   The meta-analysis demonstrated that the highest consumption of processed foods belonged to the sugars and sweets group with 8.01 S/D, followed by oils, and biscuits and cakes with 5.58 S/D and 3.33 S/D, respectively.
   East Mediterr Health J, 2021 · checked 2026-09-24