Bagels: mostly studied as the thing something else was compared against

A plain enriched bagel runs 264 kcal per 100 g, and USDA counts one bagel as 99 g. The same 100 g carries 422 mg of sodium, 1.6 g of fibre and 163 micrograms of folate. That sodium is close to a fifth of the 2,300 mg daily value, before anything goes on top. Almost everything research knows about bagels was learned while somebody was studying something else. Of the ten evidence cards under this page, five used a bagel breakfast as the fixed background against which the real variable was measured: vinegar, acacia gum, fructooligosaccharide, iron from soybean ferritin, resistant starch flour. Read those numbers as findings about the added ingredient. The bagel in them is furniture. When the bagel itself was on trial, it came second. Over 8 weeks, the adults put on an energy-deficit diet lost 1.59 kg on a bagel breakfast and 2.63 kg on an egg breakfast of the same energy. Those are the deficit arms of a trial of 152 people, and without the deficit the two breakfasts did not differ. In a separate crossover, 21 men were hungrier three hours after the bagel and ate more over the following 24 hours, with higher glucose, insulin and ghrelin. The thiamin, niacin, folate and iron on the label are put there by a federal recipe, not left over from the wheat. US enriched flour has to hold 2.9 mg of thiamin, 24 mg of niacin, 0.7 mg of folic acid and 20 mg of iron per pound.

The numbers, per 100 g

How much is actually in it

• The thiamin, niacin, folate and iron in a plain bagel come from a federal recipe: enriched flour must contain 2.9 mg of thiamin, 24 mg of niacin, 0.7 mg of folic acid and 20 mg of iron per pound. — US enriched flour, 21 CFR 137.165 standard of identity Evidence E source
  2.9 mg thiamin, 1.8 mg riboflavin, 24 mg niacin, 0.7 mg folic acid and 20 mg iron per pound of flour

What your body absorbs

• Two teaspoons of vinegar taken with a bagel and juice meal cut the 2 hour glucose rise by 20% against placebo, and had no effect when the same carbohydrate came as a simple sugar solution. — four randomised crossover trials, 9 to 10 adults each, with and without type 2 diabetes, bagel and juice test meal or a dextrose solution (n = 9 to 10 per trial) Evidence B source
  Postprandial glycaemia down 20% against placebo, effect strongest when vinegar was taken with the meal rather than 5 hours before, and absent with monosaccharides
• From a bagel, cream cheese and apple juice meal, iron from soybean ferritin was absorbed at 29.9% against 34.3% from ferrous sulfate in 16 nonanemic women, with no significant difference. — 16 healthy nonanemic women, radiolabelled iron in a standardised bagel meal, randomised crossover with 4 weeks between meals (n = 16) Evidence B source
  Whole-body absorption 29.9% from soybean ferritin against 34.3% from FeSO4, no significant difference

What it does to your health

• Replacing a wheat bagel with one containing 25 g of high-amylose maize resistant starch for 56 days cut fasting insulin area under the curve by 22.1% in 24 adults at raised risk of type 2 diabetes. — 24 men and women, mean age 55.3 years, mean BMI 30.2, one bagel a day for 56 days in each arm with a 4 week washout (n = 24) Evidence B source
  Fasting insulin AUC down 22.1% (P = 0.04), 2 hour down 23.3% (P < 0.008), HOMA-IR down 23.1% (P = 0.04), glucose unchanged
• On an energy-deficit diet for 8 weeks, an egg breakfast produced 65% more weight loss than a bagel breakfast matched for energy and energy density (2.63 kg against 1.59 kg). — the two energy-deficit arms of a trial in overweight or obese adults aged 25 to 60, randomised to an egg or a bagel breakfast on a 1000 kcal deficit diet (n = deficit arms, part of 152) Evidence B source
  Weight loss 2.63 kg against 1.59 kg (P<0.05), BMI reduction 61% greater, blood lipids unchanged between groups
• After a bagel breakfast, 21 men were hungrier at 3 hours and ate more over the following 24 hours than after an isoenergetic egg breakfast, with higher glucose, insulin and ghrelin areas under the curve. — 21 men aged 20 to 70, two isoenergetic test breakfasts a week apart, buffet lunch at 180 minutes and food records for the surrounding days (n = 21) Evidence B source
  More kilocalories over 24 hours after the bagel (P < .05), hungrier and less satisfied at 3 hours (P < .01), higher glucose, insulin and ghrelin AUC (P < .05)

Safety, limits and interactions

• Adding 40 g of acacia gum to a bagel and cream cheese breakfast raised reported bloating, flatulence and gut rumbling against control in 48 healthy adults, while raising fullness at 15 minutes. — 48 healthy adults, 24 men and 24 women, 0, 20 or 40 g of acacia gum in orange juice with a bagel and cream cheese after a 12 hour fast (n = 48) Evidence B source
  Less hunger and greater fullness at 15 minutes (p = 0.019 and 0.003) with 40 g, more bloating, flatulence and rumbling at the same dose, no change in glucose AUC
• In a UK outbreak investigation with 49 cases and 128 controls, eating egg mayonnaise bagels carried an odds ratio of 34.1 (95% CI 10.5 to 111.3) for diarrhoea, and contaminated eggs were the likely source. — attendees of a children's charity event in Hertsmere, June 2006, 49 cases and 128 controls, Salmonella Enteritidis PT13a (n = 177) Evidence C source
  OR 34.1 (95% CI 10.5 to 111.3) for egg mayonnaise bagels, OR 16.1 (95% CI 3.5 to 74.2) for apple juice

Who this works differently for

• One reported case, and how often this happens is not known: a 57 year old man went into anaphylactic shock after eating a wheat bagel and climbing five flights of stairs, arriving with a blood pressure of 72/27 mm Hg. — one man, a single case report of food-dependent exercise-induced anaphylaxis (n = 1) Evidence C source
  Blood pressure 72/27 mm Hg on arrival, recovery after antihistamine, steroid and fluids

What is still unknown

• Adding 5 g or 8 g of short-chain fructooligosaccharide to a bagel breakfast did not change morning satiety or lunch intake in 20 healthy adults. — 20 healthy adults, doses of 0, 5 or 8 g of scFOS with a bagel and cream cheese breakfast, ad libitum lunch at 240 minutes (n = 20) Evidence B source
  No difference in subjective satiety or lunch intake, breath hydrogen rose dose-dependently, 24 hour intake fell in women and rose in men at the high dose

The bottom line

Two findings here are worth carrying to breakfast, and both are small. What follows is what happened to a test breakfast in four crossover trials of 9 to 10 people each. It is not a treatment, and if you have type 2 diabetes it replaces nothing your doctor gave you. Two teaspoons of vinegar taken with a bagel and juice meal cut the 2 hour glucose rise by 20 percent against placebo across four small crossover trials of 9 to 10 adults each, in people with and without type 2 diabetes. The same vinegar did nothing when the carbohydrate arrived as a sugar solution, so this looks like an effect on starch rather than on sugar in general, and the trials are small. The other is iron. In 16 women who were not anaemic, iron from soybean ferritin eaten in a bagel, cream cheese and apple juice meal was absorbed at 29.9 percent against 34.3 percent from ferrous sulfate, a gap that did not reach significance. Then there are the bagels that are not really bagels. Swapping in a bagel made with 25 g of high-amylose maize resistant starch every day for 56 days cut fasting insulin area under the curve by 22.1 percent in 24 adults at raised risk of type 2 diabetes, while glucose did not move. That was a purpose-built product, not one off a shelf. Adding 40 g of acacia gum to a bagel and cream cheese breakfast raised fullness at 15 minutes in 48 adults and raised reported bloating, wind and gut rumbling at the same dose, with no change in glucose. Adding 5 g or 8 g of short-chain fructooligosaccharide instead changed neither morning satiety nor how much people ate at lunch. If you are adding fibre to breakfast for fullness, one of these bought some discomfort with it and the other bought nothing at all. On safety we have less than the page appears to offer. Our one outbreak card is about the filling. At a UK charity event in 2006, egg mayonnaise bagels carried an odds ratio of 34.1 (95 percent CI 10.5 to 111.3) for diarrhoea among 49 cases and 128 controls, and contaminated eggs were the likely source. That is a fact about egg mayonnaise left warm, and it would say the same about a sandwich. Beyond it we hold a single case report, a 57 year old man who went into anaphylactic shock after a wheat bagel and five flights of stairs and arrived with a blood pressure of 72/27 mm Hg. One case tells you the reaction exists in wheat-dependent exercise-induced anaphylaxis. It tells you nothing about how often. So the honest gap: we have no card on who should be careful with bagels as such. Coeliac disease, wheat allergy and the 422 mg of sodium per 100 g are all real reasons somebody might need to know more, and none of them has been researched into this page yet. We also have nothing on how bagels fit a real day, no portion data, no intake figures, and nothing from the health claim registers either way. Where a page has no card, it says nothing, and this is where that leaves it thin.

Sources

1. bagl-r4-10 · federal standard of identity
   It contains in each pound 2.9 milligrams of thiamin, 1.8 milligrams of riboflavin, 24 milligrams of niacin, 0.7 milligrams of folic acid, and 20 milligrams of iron.
   21 CFR 137.165, Enriched flour · checked 2026-09-23
2. bagl-r4-04 · randomised crossover trials
   Vinegar did not alter PPG when ingested with monosaccharides, suggesting that the antiglycemic action of vinegar is related to the digestion of carbohydrates...In these situations, vinegar attenuated PPG by 20% compared to placebo.
   Ann Nutr Metab, 2010 · checked 2026-09-23
3. bagl-r4-05 · randomised crossover isotope study
   There was no significant difference in whole-body iron absorption from soybean ferritin (29.9 +/- 19.8%) and that from FeSO4 (34.3 +/- 23.6%) or in iron absorption calculated from red blood cell incorporation (33.0 +/- 20.1% for soybean ferritin and 35.3 +/- 23.4% for FeSO4), which confirmed previous results with animal ferritin that was mineralized and labeled similarly.
   Am J Clin Nutr, 2006 · checked 2026-09-23
4. bagl-r4-01 · randomised double-blind crossover trial
   The RS bagel treatment resulted in significantly lower fasting (22.1%, P = 0.04), 2-h (23.3%, P < 0.008), and 3-h (18.9%, P = 0.05) insulin incremental areas under the curve and fasting insulin resistance (homeostasis model assessment of insulin resistance; 23.1%, P = 0.04) than did the control bagel treatment.
   J Nutr, 2016 · checked 2026-09-23
5. bagl-r4-02 · randomised controlled trial
   After 8 weeks, in comparison to the BD group, the ED group showed a 61% greater reduction in BMI (-0.95+/-0.82 vs -0.59+/-0.85, P<0.05), a 65% greater weight loss (-2.63+/-2.33 vs -1.59+/-2.38 kg, P<0.05), a 34% greater reduction in waist circumference (P<0.06) and a 16% greater reduction in percent body fat (P=not significant).
   Int J Obes (Lond), 2008 · checked 2026-09-23
6. bagl-r4-03 · randomised crossover trial
   Based on VAS, subjects were hungrier and less satisfied 3 hours after the BAGEL breakfast compared with the EGG breakfast (P < .01).
   Nutr Res, 2010 · checked 2026-09-23
7. bagl-r4-06 · randomised double-blind crossover trial
   Subjects reported more bloating, flatulence, and GI rumbling on the 40 g fiber treatment compared to control, although values for GI tolerance were all low with AG treatment.
   Nutrients, 2021 · checked 2026-09-23
8. bagl-r4-08 · case-control outbreak investigation
   Risk factors for diarrhoea were eating egg mayonnaise bagels (OR=34.1, 95%CI 10.5 - 111.3) and drinking apple juice (OR=16.1, 95% CI 3.5 - 74.2).
   Euro Surveill, 2007 · checked 2026-09-23
9. bagl-r4-09 · case report
   A 57-year-old man was found with a diffuse erythematous rash after eating a wheat bagel and walking up five flights of stairs.
   J Emerg Med, 2012 · checked 2026-09-23
10. bagl-r4-07 · double-blind crossover trial
    These results indicate that scFOS undergoes fermentation within 240 min; however, acceptable amounts of scFOS did not enhance acute satiety or hunger.
    Appetite, 2011 · checked 2026-09-23