Daily broccoli intake, body weight and absorption of plant compounds in people
What it found
Eating broccoli every day changed how much of its plant compounds reached the blood and urine, but the effect depended on body weight.
People with a lower BMI absorbed more after daily eating, while those with a higher BMI absorbed less.
What they found
Studies in people
Body weight changed absorption
For people with a BMI below 26, eating broccoli daily raised blood levels of plant compounds by 17% compared to the no broccoli diet. For people with a BMI above 26, daily broccoli lowered those blood levels by 28%.
Urine output matched blood
The amount of compounds passed in urine over 24 hours followed the same pattern as blood levels. Lower BMI participants excreted more after daily broccoli, while higher BMI participants excreted less.
Genes did not matter
A specific gene variant called GSTM1 did not change how the body handled the broccoli compounds. The results were also similar between men and women.
Gut lining permeability
A test measuring how easily substances pass through the gut lining showed slightly higher values during the daily broccoli diet. This result did not differ between the BMI groups.
Compounds measured in blood
Researchers tracked nine breakdown products from broccoli in the blood and urine. Even though one starting compound made up 94% of what was eaten, its direct breakdown products only accounted for about a third of what appeared in the blood.
What the authors conclude
- They found that eating broccoli every day changed blood and urine levels of its plant compounds, and this change depended on body weight.
- They say these results point to a need for personalised dietary advice about eating broccoli and similar vegetables.
- They call for more research to find out whether regular broccoli eating is better than occasional eating for people whose bodies absorb less of these compounds over time.
How it was done
Broccoli contains natural plant compounds linked to cancer protection in earlier research. An animal study suggested that eating broccoli every day might change how much of these compounds the body can take in and use.
Eighteen healthy adults followed two diets for 16 days each, separated by a three week break. One diet had no broccoli, and the other included 200 g of cooked broccoli plus 20 g of raw daikon radish every day. On day 17 everyone ate the same broccoli meal, and researchers collected blood and urine for 24 hours.
What it can’t tell you
- This trial only measured how much of the compounds reached the blood and urine, so it cannot show whether daily broccoli eating actually prevents disease.
- The study used frozen broccoli served with raw daikon radish, so the results may not match what happens when people eat fresh broccoli on its own.
- With only 18 participants split into two BMI groups, scientists do not yet know if these patterns hold true for larger or more diverse populations.
Who paid
- Authors work at
- 1US Department of Agriculture, USA; 2US Department of Agriculture, USA; National Institutes of Health, USA
The paper
- Title
- Absorption and metabolism of isothiocyanates formed from broccoli glucosinolates: effects of BMI and daily consumption in a randomised clinical trial
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Charron CS, Vinyard BT, Ross SA, Seifried HE, Jeffery EH, Novotny JA (2018). Absorption and metabolism of isothiocyanates formed from broccoli glucosinolates: effects of BMI and daily consumption in a randomised clinical trial. The British journal of nutrition. doi:10.1017/S0007114518002921Free full textPubMed 30499426DOI
Summary written 1 Oct 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error