Barley flour: the cholesterol effect needs a lot of it

A meta-analysis of 14 randomized trials in 615 people found that diets enriched with about 6.5 g a day of barley beta-glucan lowered LDL cholesterol by 9.7 mg/dL (95% CI 7.7 to 12; metric: 0.25 mmol/L, 0.20 to 0.30) over a median of 4 weeks. Beta-glucan is the soluble fiber in barley, and apoB did not change. An earlier meta-analysis of 11 trials, which pooled whole barley foods with isolated beta-glucan, found LDL down 10 mg/dL (0.27 mmol/L) and no clear dose response. The catch is the dose. Barley flour holds about 4.2 g beta-glucan per 3.5 oz (100 g), so 6.5 g means roughly 5.3 oz (150 g) of flour a day, and no long trial has tested the flour itself. Across 8 US samples, its fiber averaged 12.8 g per 3.5 oz (100 g) but ranged from 9.9 to 20.1 g, while beta-glucan stayed between 3.8 and 4.6 g. Whole grain and pearled flours likely explain that spread.

The numbers, per 3.5 oz (100 g)

How much is actually in it

• Across 8 USDA samples, barley flour held 12.8 g fiber per 3.5 oz (100 g) on average but ranged from 9.9 to 20.1 g, while its beta-glucan stayed close to 4.2 g. — USDA Foundation Foods record Flour, barley (FDC 2512376), 8 analyzed samples (n = 8 samples) Evidence E source
  Per 100 g: fiber 12.79 g (9.85 to 20.1), beta-glucan 4.2 g (3.8 to 4.6), iron 3.30 mg (1.66 to 6.28), protein 8.7 g (6.8 to 10.8), niacin 5.94 mg (3.91 to 8.63)

What your body absorbs

• In a randomized crossover trial in 13 adults, muffins with 48 g whole barley flour did not raise blood levels of tocopherols, phenolic acids or alkylresorcinols more than refined wheat. — 13 overweight or mildly obese adults aged 40 to 70, muffins with 48 g whole oat, whole barley or refined wheat flour, one week washout (n = 13) Evidence B source
  No significant difference in Cmax or Tmax of major phytochemicals between barley, oat and wheat muffins

What cooking and storage change

• Baked into muffins, wholegrain barley flour gave a glycemic index of 55 against 74 for refined wheat flour in 12 healthy adults. — 12 healthy participants eating muffins made with wheat, rice, corn, oat or barley flour, randomized crossover (n = 12) Evidence B source
  GI 55 barley versus 74 wheat, 79 rice, 74 corn and 53 oat muffins
• In a double blind trial in 12 adults, barley flour tortillas milled to 11.6 g beta-glucan lowered glucose and insulin responses compared with 4.5 g versions, while amylose made no difference. — 12 healthy adults eating 100% barley flour tortillas built from different milling fractions, each with 50 g available carbohydrate (n = 12) Evidence B source
  Lower glucose and insulin response with high beta-glucan (11.6 g) than low (4.5 g); amylose and insoluble fiber did not change glucose

What it does to your health

• A meta-analysis of 14 randomized trials in 615 people found that about 6.5 g a day of barley beta-glucan for a median 4 weeks lowered LDL cholesterol by 9.7 mg/dL (0.25 mmol/L). — 14 RCTs, 615 participants, diets enriched with barley beta-glucan for at least 3 weeks versus control diets (n = 615) Evidence A source
  LDL-C -9.7 mg/dL (95% CI -12 to -7.7; metric: -0.25 mmol/L, -0.30 to -0.20); non-HDL-C -12 mg/dL (95% CI -15 to -8.9; metric: -0.31 mmol/L, -0.39 to -0.23); no change in apoB
• An earlier meta-analysis of 11 randomized trials found barley and barley beta-glucan lowered total cholesterol by 12 mg/dL (0.30 mmol/L) and LDL by 10 mg/dL (0.27 mmol/L), with no clear dose response. — 11 randomized clinical trials published 1989 to 2008 (n = 11 trials) Evidence A source
  Total cholesterol -12 mg/dL (95% CI -15 to -8.1; metric: -0.30 mmol/L, -0.39 to -0.21); LDL -10 mg/dL (95% CI -13 to -7.7; metric: -0.27 mmol/L, -0.34 to -0.20)
• In 14 healthy women, wheat meals gave a 22% higher glucose response than barley flour meals, yet barley did not curb eating later in the day. — 14 healthy women, breakfast and lunch with high amylose, high soluble fiber barley flour or white wheat flour, randomized crossover (n = 14) Evidence B source
  Glucose AUC 66 versus 84 mg/dL (3.67 versus 4.68 mmol/l)/h (wheat 22% higher, P = 0.05); insulin AUC 32% higher after wheat; food intake over 10 h 11.0 MJ after barley versus 9.6 MJ after wheat

Safety, limits and interactions

• A case report describes a 50 year old man whose asthma was triggered both by breathing barley flour dust and by drinking barley beer, through an IgE allergy. — One 50 year old man with occupational exposure to cereal flours (n = 1) Evidence C source
  Immediate asthmatic response to bronchial and oral challenge with barley flour
• In a survey of 1,655 Tibetan children under three, 89.1% had been given zanba, a mix of highland barley flour and butter, starting at about 2 months of age. — 1,655 Tibetan children under 3 years, randomly sampled, mothers' recall (n = 1655) Evidence C source
  Zanba introduced at a mean 1.98 months; 89.1% introduced

What people believe that the data does not support

• US rules name barley flour as an eligible source for the soluble fiber and heart disease health claim, if it holds at least 4% beta-glucan and 8% total fiber on a dry basis. — Dry milled barley products sold in the United States Evidence E source
  Eligible source when beta-glucan is at least 4% and total dietary fiber at least 8% dry weight

Who this works differently for

• In 20 adults with type 2 diabetes, bread made with 75% hulless barley flour cut the 4 hour blood glucose response by 11% compared with all wheat bread. — 20 Caucasian adults with type 2 diabetes not on insulin (18 completed), single test meals at four visits, Aarhus 2021 (n = 20) Evidence B source
  Glucose iAUC -11% with 75% hulless barley bread versus 100% wheat (P < 0.05); -34% with 50% high amylose barley flour

What is still unknown

• The 13 person trial of 48 g barley flour found no acute benefit, and its authors say the dose, the subjects chosen and the glucose load given alongside may explain the null result. — 13 overweight adults aged 40 to 70, single 48 g dose of whole barley flour (n = 13) Evidence B source
  Null results with no clear cause

The bottom line

In single test meals, swapping some wheat for barley flattened the blood sugar rise. In 20 adults with type 2 diabetes, bread made with 75 percent hulless barley flour cut the 4 hour glucose response by 11 percent compared with all wheat bread, in single test meals. Muffins of wholegrain barley flour gave a glycemic index of 55 against 74 for refined wheat in 12 healthy adults, from one recipe. In 12 adults eating barley tortillas, versions milled to 11.6 g beta-glucan lowered glucose and insulin more than 4.5 g versions, and the abstract does not give the size of the drop. In 14 healthy women, wheat meals produced a glucose response 22 percent higher than meals with a special high fiber barley cultivar (P = 0.05). Those women ate no less later in the day, 11.0 MJ after barley against 9.6 MJ after wheat. Muffins with 48 g whole barley flour did not raise blood levels of tocopherols or phenolic acids more than wheat in 13 adults. The authors say the dose, the people chosen and the glucose drink given alongside may explain that null result. US rules let barley flour carry the soluble fiber and heart disease claim when it holds at least 4 percent beta-glucan and 8 percent total fiber on a dry basis. That is a permission to make the claim, and it says nothing about how big the effect is. Barley contains gluten proteins called hordeins, which matters for anyone with celiac disease. A single case report describes a 50 year old man with IgE allergy whose asthma was triggered by barley flour dust and by barley beer. In a survey of 1,655 Tibetan children under three, 89.1 percent had been given zanba, highland barley flour mixed with butter, from about 2 months of age, well before the 6 months advised for solids. We have no card on pregnancy or on medicines for barley flour.

Sources

1. bflr-r5-01 · USDA FoodData Central Foundation Foods, dataset
   Flour, barley (FDC 2512376, Foundation): Fiber, total dietary 12.79 g per 100 g, range 9.85-20.1, n=8; Beta-glucan 4.2 g, range 3.8-4.6, n=8; Iron, Fe 3.301 mg, range 1.66-6.28, n=8; Protein 8.72 g, range 6.82-10.79; Niacin 5.941 mg, range 3.91-8.63, n=8
   USDA FoodData Central, Foundation Foods, release 2026-04-30, Flour, barley (FDC 2512376) · checked 2026-10-02
2. bflr-r5-07 · randomized crossover trial
   There was no significant effect on acute bioavailability or pharmacokinetics of major phytochemicals.
   Nutrients, 2016 · checked 2026-10-02
3. bflr-r5-05 · randomized crossover trial
   Muffins baked with wheat, rice, corn, oat and barley flours gave rise to GI values of 74, 79, 74, 53 and 55, respectively.
   Eur J Nutr, 2015 · checked 2026-10-02
4. bflr-r5-06 · randomized crossover trial
   Amylose and insoluble fibre content did not alter postprandial glucose and insulin, but high-β-glucan tortillas elicited a lower glucose and insulin response as compared to the low-β-glucan tortillas.
   Br J Nutr, 2015 · checked 2026-10-02
5. bflr-r5-02 · meta-analysis of randomized trials
   A median dose of 6.5 and 6.9 g/day of barley β-glucan for a median duration of 4 weeks significantly reduced LDL-C (MD=-0.25 mmol/l (95% CI: -0.30, -0.20)) and non-HDL-C (MD=-0.31 mmol/l (95% CI: -0.39, -0.23)), respectively, with no significant changes to apoB levels, compared with control diets.
   Eur J Clin Nutr, 2016 · checked 2026-10-02
6. bflr-r5-03 · meta-analysis of randomized trials
   Overall, barley and β-glucan isolated from barley lowered total and low-density lipoprotein (LDL) cholesterol concentrations by 0.30 mmol/l (95% confidence interval (CI): -0.39 to -0.21, P<0.00001) and 0.27 mmol/l (95% CI: -0.34 to -0.20, P<0.00001), respectively, compared with control.
   Eur J Clin Nutr, 2010 · checked 2026-10-02
7. bflr-r5-08 · randomized crossover trial
   Mean area under the glycaemic response curve (AUC) for wheat-containing meals was 4.68+/-1.67 mmol/l/h, 22% higher than for the barley-containing meals (3.67+/-1.91 mmol/l/h), P=0.05.
   Eur J Clin Nutr, 2007 · checked 2026-10-02
8. bflr-r5-10 · case report
   The most relevant clinical feature was an immediate asthmatic response developed after oral provocation with either barley-made beer or barley flour itself which indicates IgE-mediated, food-induced bronchial asthma (sulfite sensitivity was ruled out).
   Ann Allergy Asthma Immunol, 1995 · checked 2026-10-02
9. bflr-r5-11 · cross-sectional survey
   The findings indicated that the age of introduction of Zanba (a kind food of mixture of highland barley flour and butter) was 1.98 months after birth and the age of introduction of egg and meat was about 8 - 9 months.
   Zhonghua Liu Xing Bing Xue Za Zhi, 2003 · checked 2026-10-02
10. bflr-r5-09 · US health claim regulation
    Dry milled barley grain products include barley bran, barley flakes, barley grits, pearl barley, barley flour, barley meal, and sieved barley meal that are produced from clean, sound dehulled or hull-less barley grain using standard dry milling techniques, which may include steaming or tempering, and that contain at least 4 percent (dwb) of β-glucan soluble fiber and at least 8 percent (dwb) of total dietary fiber
    21 CFR 101.81, Health claims: soluble fiber from certain foods and risk of coronary heart disease · checked 2026-10-02
11. bflr-r5-04 · randomized crossover trial
    Bread made from 75% hulless barley reduced the postprandial glucose response (iAUC) by 11% (P < 0.05) compared to 100% wheat bread.
    Eur J Clin Nutr, 2024 · checked 2026-10-02
12. bflr-r5-12 · randomized crossover trial
    These null results may be due, in part, to the inclusion criteria for the subjects, dose of the whole grains, and concurrent acute administration of the whole grains with the glucose bolus.
    Nutrients, 2016 · checked 2026-10-02