Shortbread cookies: studied only as a carrier

In a 10 day randomized trial, inulin baked into shortbread biscuits raised fecal Bifidobacterium by 0.59 log10 cells per gram, close to the 0.63 rise from pure inulin, and the abstract does not say how many people took part. That is the pattern on this page. The shortbread in the research carries something else, and we found no trial of plain shortbread as a food. In 8 non-diabetic volunteers given single test meals, shortbread made with guar gum left blood glucose rises unchanged and cut the insulin response by an estimated 209 mU/min/l for each gram of guar. That trial dates from 1988 and used modified biscuits. In glycemic index testing on 78 young adults in Poland, sucrose-sweetened shortbread without fruit pomace landed in the medium range in two baking series and the high range in the third. The test was not randomized, and the volunteers were young and healthy.

The numbers, per 3.5 oz (100 g)

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

How much is actually in it

• USDA SR Legacy lists reduced-fat shortbread cookies at 76 g carbohydrate, 0.35 mg thiamin and 113 ug folate per 3.5 oz (100 g), with carbohydrate from 58.3 to 76 g across three shortbread records. — USDA FoodData Central SR Legacy, Cookies, shortbread, reduced fat (FDC 174087) and two commercially prepared shortbread records (n = 3 records) Evidence E source
  Carbohydrate 75.99 g (58.3-75.99), thiamin 0.353 mg (0.293-0.353), folate 113 ug (102-124) per 3.5 oz (100 g)

What a real portion looks like

• In the USDA survey food table a medium shortbread cookie weighs 1.1 oz (30 g), a small one 20 g and a large one 45 g. — USDA FNDDS Cookie, shortbread, food code 53239000, fdc_id 2707964, WWEIA category Cookies and brownies Evidence E source
  Bite size 5 g, small 20 g, medium 30 g, large 45 g, quantity not specified 60 g

What your body absorbs

• In a 10 day randomized trial, inulin baked into shortbread biscuits raised fecal Bifidobacterium by 0.59 log10 cells/g, close to the 0.63 rise from pure inulin. — adults in a 4-arm parallel randomized protocol, inulin as pure powder or in shortbread biscuits, milk chocolate or a rice drink, 10 days Evidence B source
  Bifidobacterium +0.59 (shortbread) vs +0.63 (pure inulin), +0.65 (chocolate), +0.71 (rice drink) log10 cells/g wet feces, all P <= 0.05
• In glycemic index testing on 78 young adults, sucrose-sweetened shortbread cookies with 0% or 10% fruit pomace fell in the medium or high glycemic index range. — 78 adults, mean age 21.7 years, BMI 21.2, Wroclaw, Poland, 2022-2023, ISO 26642:2010 protocol (n = 78) Evidence C source
  Control sucrose cookies medium GI (chokeberry and blackcurrant series) or high GI (apple series), GI fell as pomace share rose

What it does to your health

• In a randomized trial in 8 non-diabetic volunteers, adding guar gum to shortbread biscuits did not change blood glucose rises but cut the integrated insulin response by an estimated 209 mU/min/l per gram of guar. — 8 non-diabetic volunteers, control biscuit and guar biscuits with 2.9, 6.0 and 9.1 g guar, single test meals (n = 8) Evidence B source
  No significant difference in glucose increments, integrated insulin -209 mU/min/l per 1 g guar

Safety, limits and interactions

• A meta-analysis of 28 processing studies found that baking lowered the mycotoxins deoxynivalenol and zearalenone in biscuits. — 28 articles, 549 data points on cereal-based products, 1983 to June 2017 (n = 549 data points) Evidence C source
  Direction only, DON and ZEN reduced by cooking in biscuits

What people believe that the data does not support

• A meta-analysis of 17 prospective cohorts with over 875000 people found refined grain intake, including analyses that counted cookies and cakes, was not significantly linked to cardiovascular disease. — 17 prospective cohort studies, more than 875000 participants (n = 875000) Evidence C source
  CVD HR 1.08 (0.99-1.18), stroke HR 1.06 (0.92-1.23), heart failure HR 0.95 (0.77-1.16)

What is still unknown

• A meta-analysis of 28 studies on wheat foods found acrylamide the most studied baking contaminant, measured mostly in bread, cookies and pasta, with a pooled mean of 136 ug/kg. — 28 studies on processing contaminants in wheat-based foods (n = 28 studies) Evidence C source
  Acrylamide 136.29 ug/kg, HMF 70.59 ug/kg, PAHs 0.11 ug/kg

The bottom line

What is in it depends on the recipe. Three USDA records put carbohydrate between 58.3 and 76 g per 3.5 oz (100 g). The reduced fat record lists 0.35 mg thiamin and 113 mcg folate per 3.5 oz (100 g), which come from US enriched flour and do not carry over to British or European shortbread. A medium cookie weighs 1.1 oz (30 g) in the US survey table and a small one 20 g. An unspecified portion is 60 g, two medium cookies. A meta-analysis of 17 prospective cohorts with more than 875000 people found refined grain intake was not significantly linked to cardiovascular disease (HR 1.08, 0.99 to 1.18), including in analyses that counted cookies and cakes. Shortbread has no figure of its own there, and the authors expect residual confounding. It is a null result for a broad category. Baking lowered the mycotoxins deoxynivalenol and zearalenone in biscuits, according to a meta-analysis of 28 processing studies that gives the direction without a size. Acrylamide is the contaminant studied most in wheat foods. Across 28 studies, mostly of bread, cookies and pasta, its pooled mean was 136 mcg/kg, with no separate figure for shortbread and no commercial samples at all from some regions. Who should be careful. Our cards for this page cover baking contaminants only. We have no card on wheat or milk allergy, children, pregnancy or medicines, and that is a gap in what we hold, which you should not read as reassurance.

Sources

1. sbk-r5-08 · reference dataset
   Cookies, shortbread, reduced fat | FDC 174087 | carbohydrate 75.99 g | thiamin 0.353 mg | folate 113 ug per 100 g ; 3 records: carbohydrate 58.3-75.99 g
   USDA FoodData Central, SR Legacy, FDC 174087 · checked 2026-09-28
2. sbk-r5-07 · reference dataset
   Cookie, shortbread | FNDDS code 53239000 | fdc_id 2707964 | 1 small 62015 = 20 g | 1 medium 61238 = 30 g | 1 large 60919 = 45 g | Quantity not specified 90000 = 60 g
   USDA FNDDS, Cookie shortbread, food code 53239000, fdc_id 2707964 · checked 2026-09-28
3. sbk-r5-01 · randomized controlled trial
   In this randomised trial, we aimed to determine the effects that different food matrices had on the prebiotic efficacy of inulin-type fructans following a standardised 10-day, 4-arm, parallel, randomised protocol with inulin either in pure form or incorporated into shortbread biscuits, milk chocolate or a rice drink. Similar increases in Bifidobacterium counts were documented across all four interventions using both fluorescence in situ hybridisation (pure inulin: +0.63; shortbread: +0.59; milk chocolate: +0.65 and rice drink: +0.71 (log10 cells/g wet faeces)
   Benef Microbes, 2023 · checked 2026-09-28
4. sbk-r5-03 · glycemic index study
   In the end, 78 individuals with a mean age of 21.7 ± 1.2 years ... Regardless of pomace type, products sweetened with sucrose (addition of 0% and 10% of fruit pomace) were classified as products with medium GI (chokeberry, blackcurrant) or high GI (apple).
   Sci Rep, 2024 · checked 2026-09-28
5. sbk-r5-02 · randomized controlled trial
   A control biscuit and three types of guar biscuit corresponding to a low, medium and high dose of guar (2.9, 6.0 and 9.1 g of guar respectively) were given to 8 non-diabetic subjects, and blood glucose and plasma insulin levels were determined at fasting, and at the postprandial times 30, 60, 90 and 120 min. ... No significant differences in the blood glucose increments were found between the control biscuit and the guar biscuits. ... We have estimated from this model that a reduction of 209 mU/min/l in the integrated insulin can be achieved for every 1 g of guar incorporated into the biscuit.
   Eur J Clin Nutr, 1988 · checked 2026-09-28
6. sbk-r5-06 · meta-analysis
   Cooking reduces the concentration of DON and ZEN in the biscuit.
   Food Chem, 2018 · checked 2026-09-28
7. sbk-r5-04 · meta-analysis of cohorts
   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) ... as well as for meta-analyses of studies that included both staple and indulgent grain foods (e.g., cakes, cookies, doughnuts, brownies, muffins, pastries).
   Trends Cardiovasc Med, 2024 · checked 2026-09-28
8. sbk-r5-05 · meta-analysis
   Most studies (69.7%) evaluated acrylamide in bread, cookies, and pasta, while PAHs (26.2%) were determined mainly in wheat grains and pasta. ... The highest concentration was for acrylamide (136.29 µg·kg-1) followed by HMF (70.59 µg·kg-1) and PAHs (0.11 µg·kg-1). Acrylamide is the main processing contaminant researched, and no studies on the subject have been found in commercial samples in some regions of the world.
   Crit Rev Food Sci Nutr, 2023 · checked 2026-09-28