Italian bread: an ordinary refined loaf, judged by the slice

We found no study on Italian bread itself, so this page leans on refined wheat bread and refined grains in general. In the clearest trial, swapping one bread for another did not move blood sugar. In 194 adults at risk of type 2 diabetes, at least 3 slices a day of oat beta-glucan bread instead of whole-grain wheat bread for 16 weeks left HbA1c unchanged, a difference of -0.01 percent (95% CI -0.03 to 0.06). Neither bread was Italian white bread. Observational data across 17 cohorts of more than 875,000 people do not link refined grains to heart disease (HR 1.08, 95% CI 0.99 to 1.18) or stroke. Cohorts are confounded, and no link is not proof of benefit. What the loaf does carry is enriched flour. USDA lists 0.58 mg of thiamin per 3.5 oz (100 g), 48 percent of the Daily Value, and 132 mcg of folate from one legacy record, and a loaf made from unenriched flour outside the US may not reach those numbers. A regular slice is 31 g in the US dietary survey, about 0.18 mg of thiamin and 41 mcg of folate by recalculation.

The numbers, per 3.5 oz (100 g)

As people eat it, per 3.5 oz (100 g)

How much is actually in it

• According to the NIH Office of Dietary Supplements, baked bread has 20% to 30% less thiamin than its raw ingredients. — NIH ODS thiamin fact sheet for health professionals Evidence E source
  Thiamin 20-30% lower in bread than in raw ingredients

What a real portion looks like

• A regular slice of Italian bread in the US dietary survey weighs 1.1 oz (31 g), a thick slice 43 g, and a whole 10-inch loaf 454 g. — FNDDS food code 51109010, Bread, Italian, Grecian, Armenian, portion weights used to code NHANES recalls Evidence E source
  Thin slice 24 g, regular slice 31 g, thick slice 43 g, individual loaf 82 g, 10-3/4 inch loaf 454 g; a regular slice is about 0.18 mg thiamin and 41 mcg folate scaled from SR Legacy 100 g values

What your body absorbs

• A review of 8 bread trials found low-phytate white bread raised serum iron more in 2 hours than high-phytate whole wheat, 59 vs 30 mcg/100 mL, but long sourdough trials did not improve iron stores. — 8 human intervention studies, healthy or iron-deficient participants, 1970 to 2024 (n = 8 studies) Evidence A source
  Acute serum iron rise 59 vs 30 mcg Fe/100 mL; in a 12-week low-phytate sourdough rye arm ferritin fell from 32 to 27 mcg/L

What it does to your health

• Observational data show no clear link between refined grains and high blood pressure, while whole grains go with 14% lower risk per 90 g a day. — 9 prospective cohort studies from the US, Europe and Asia (n = 9 cohorts) Evidence C source
  Refined grain RR 0.97 per 90 g/d (95% CI 0.93-1.02); whole grain RR 0.86 per 90 g/d (0.82-0.90)
• An umbrella reanalysis of meta-analyses links refined grain intake with 36% higher risk of gastric cancer, with strong differences by region. — 75 systematic reviews and meta-analyses, 117 association pairs, reanalysed (n = 75 reviews) Evidence C source
  Refined grain RR 1.36 (95% CI 1.21-1.53); salt RR 1.41 (1.04-1.91)

What people believe that the data does not support

• In a 16-week RCT on 194 adults at risk of diabetes, eating at least 3 slices a day of oat beta-glucan bread instead of whole-grain wheat bread did not change HbA1c. — 194 adults, mean age 58, BMI 32, at risk of type 2 diabetes, Germany, Norway and Sweden, 16 weeks (n = 194) Evidence B source
  HbA1c difference -0.01% (95% CI -0.03 to 0.06); LDL difference -4.3 mg/dL (-10 to 1.9; metric: -0.11 mmol/L, -0.27 to 0.05)
• Observational data across 17 cohorts of over 875,000 people do not link refined grains, staple breads included, to heart disease or stroke. — 17 prospective cohort studies, more than 875,000 participants (n = 875000) Evidence C source
  CVD HR 1.08 (95% CI 0.99-1.18), stroke HR 1.06 (0.92-1.23), heart failure HR 0.95 (0.77-1.16)
• The EU did not authorize a claim that high-fiber sourdough rye bread lowers blood sugar after meals, and no bread-specific glycemic claim is authorized. — EU Register on nutrition and health claims Evidence E source
  Status Non-authorized

Who this works differently for

• In a stable-isotope RCT in Senegal, drinking a polyphenol-rich herbal tea with iron-fortified wheat bread cut iron absorption by 56% in mothers and 65% in children. — 17 Senegalese mother-child pairs, fortified wheat bread with labeled ferrous sulfate or ferrous fumarate, with herbal tea or water (n = 17 pairs) Evidence B source
  Tea lowered fractional iron absorption by 56% (FeSO4) and 50% (FeFum) in mothers and by 65% and 72% in children

What is still unknown

• USDA puts Italian bread at 0.58 mg of thiamin, 132 mcg of folate and 17.2 mcg of selenium per 3.5 oz (100 g), numbers that come largely from enriched flour. — USDA SR Legacy record for Bread, Italian (n = 1 record) Evidence E source
  Thiamin 0.582 mg per 3.5 oz (100 g) (48% DV), folate 132 mcg (33% DV), selenium 17.2 mcg (31% DV)

The bottom line

Iron from bread depends on what comes with it. In a randomized isotope study of 17 Senegalese mother and child pairs eating iron-fortified wheat bread, a local polyphenol-rich herbal tea cut iron absorption from ferrous sulfate by 56 percent in mothers and 65 percent in children, measured on single test meals. A review of 8 bread trials found low-phytate white bread raised serum iron more over 2 hours than high-phytate whole wheat, 59 against 30 mcg per 3.4 fl oz (100 mL). Its authors still call the results inconclusive, because longer sourdough trials did not improve iron stores and most trials carried a high risk of bias. Baking costs thiamin. The NIH Office of Dietary Supplements says bread has 20 to 30 percent less thiamin than its raw ingredients, a general figure that was not measured on Italian bread. Refined grains show no clear link with high blood pressure (RR 0.97 per 90 g a day, 95% CI 0.93 to 1.02, from only 4 cohorts), while whole grains go with 14 percent lower risk per 90 g a day. Italian bread is usually refined, so that whole-grain association does not cover it. An umbrella reanalysis of observational meta-analyses links refined grain intake with 36 percent higher risk of gastric cancer (RR 1.36, 95% CI 1.21 to 1.53), and the diet findings differed between regions. The EU refused a claim that high-fiber sourdough rye bread lowers blood sugar after meals. That refusal means the evidence fell short when assessed, and it concerned rye sourdough. Who should be careful. This page has no safety evidence for Italian bread, with no card on allergy, pregnancy or medicines. The one finding about children here is the tea and iron result above.

Sources

1. itbr-r8-03 · government fact sheet
   Heating foods containing thiamin can reduce their thiamin content. For example, bread has 20%–30% less thiamin than its raw ingredients, and pasteurization reduces thiamin content (which is very small to begin with) in milk by up to 20% [3].
   NIH Office of Dietary Supplements, Thiamin fact sheet for health professionals · checked 2026-10-02
2. itbr-r8-02 · USDA FNDDS portion weights, dataset
   Bread, Italian, Grecian, Armenian (FNDDS 51109010, fdc 2707614, WWEIA Yeast breads): 1 small or thin/very thin slice 24 g; 1 medium or regular slice 31 g; 1 large or thick slice 43 g; 1 individual loaf 82 g; 1 loaf (10-3/4" long) 454 g; Quantity not specified 31 g
   USDA FNDDS, food code 51109010 (fdc 2707614) · checked 2026-10-02
3. itbr-r8-05 · systematic review of intervention trials
   Results were inconclusive as acute postprandial studies increased non-haem iron bioavailability (especially in low-phytate breads); for example, low-phytate white bread produced a greater 2 h increase in serum iron than high-phytate wholemeal bread (59 vs. 30 μg Fe/100 mL), while exogenous phytase increased iron absorption by 50% for ferrous sulfate and 61% for iron bis-glycine chelate.
   Front Nutr, 2026 · checked 2026-10-02
4. itbr-r8-08 · meta-analysis of cohort studies
   The summary RR (95% CI) for high vs. low refined grain intake was 0.94 (0.88-1.01, I2 = 7.9%, pheterogeneity=0.36, n = 5) and per 90 g/d was 0.97 (0.93-1.02, I2 = 0%, pheterogeneity=0.42, n = 4).
   Sci Rep, 2025 · checked 2026-10-02
5. itbr-r8-09 · umbrella review of observational meta-analyses
   Positive associations were observed for heavy alcohol consumption (relative risk [RR], 1.13; 95% confidence interval [CI], 1.06-1.12), refined grain consumption (RR, 1.36; 95% CI, 1.21-1.53), and habitual salt intake (RR, 1.41; 95% CI, 1.04-1.91).
   J Gastric Cancer, 2025 · checked 2026-10-02
6. itbr-r8-06 · randomized controlled trial
   After 16 wk, there was no significant between-group difference in HbA1c [Δ = -0.01%, 95% confidence interval (CI): -0.03, 0.06; P = 0.49].
   Am J Clin Nutr, 2025 · checked 2026-10-02
7. itbr-r8-07 · meta-analysis of cohort studies
   Meta-analyses of hazard ratios (HR) and 95% confidence intervals (CI) obtained from 17 prospective cohort studies (>875,000 participants) indicated that refined grain intake was not associated with risk of CVD (HR = 1.08, 95% CI, 0.99-1.18, I2 = 70%; 9 cohorts), stroke (HR = 1.06, 95% CI 0.92-1.23, I2 = 70%; 9 cohorts), or heart failure (HR = 0.95, 95% CI 0.77-1.16, I2 = 10%; 5 cohorts).
   Trends Cardiovasc Med, 2024 · checked 2026-10-02
8. itbr-r8-10 · EU health claim register entry
   POL-HC-8470 High-fibre sourdough rye bread Reduction of post-prandial glycaemic responses compared with glucose -/- Non-authorised
   EU Register on nutrition and health claims, claim POL-HC-8470, snapshot 2026-09-21 · checked 2026-10-02
9. itbr-r8-04 · randomized controlled trial
   In mothers, the presence of TK decreased FAFe by 56% (P < 0.05) and 50% (P = 0.077) and in children by 65 and 72% (both, P < 0.0001), in the meals with 58FeSO4 and 57FeFum, respectively.
   Eur J Clin Nutr, 2020 · checked 2026-10-02
10. itbr-r8-01 · USDA FoodData Central SR Legacy, dataset
    Bread, Italian (FDC 174913, SR Legacy, Baked Products): thiamin 0.582 mg per 100 g = 48% DV; folate 132 mcg = 33% DV; selenium 17.2 mcg = 31% DV; Foundation samples 0, CoFID match none
    USDA FoodData Central, SR Legacy, FDC 174913 · checked 2026-10-02