If a zucchini tastes bitter, don't eat it.The toxin survives cooking. [source]
In plain English
Zucchini sold in stores are bred to be free of , the bitter defense chemicals of the squash family. The trait can come back, and bitter squash have had 93–310 mg per 100 g. Cooking does not destroy them. In Germany in 2015 a man died after eating a stew of bitter home-grown zucchini; a French series from 2012–16 recorded 353 patients and no deaths. Germany's food-safety agency advises: taste a little raw first, and don't use it if it's bitter. 100 g raw has 17.9 mg vitamin C, 23.9% of the 75 mg US for women.
100 g raw, for a 31–50-year-old woman, 70 kg. Each compound on its own; they are never added together.
1 compound listed for this food has no amount for raw; it is under Show the numbers.
What changes it
Cucurbitacins: Heat-stable: cooking does NOT destroy them. [source]
Ripe fruit is the one part of a plant that 'wants' to be eaten, so its seeds get spread, and it drops its defenses as it ripens. Green tomatoes carry 0.9–55 mg of tomatine per 100 g; red ones 0.03–0.08 mg (Friedman & Levin 1995). Seeds, roots, tubers and leaves stay defended.
The US National Academies: 'The lower limit of dietary carbohydrate compatible with life apparently is zero, provided that adequate amounts of protein and fat are consumed.' The same report says the amount that gives optimal health 'is unknown', and still sets a recommended 130 g a day. [IOM 2005, p. 275][RDA 130 g a day]
The same 100 g against five sets of daily amounts for adults aged 31–50: US/Canada (National Academies), UK (PHE 2016), EU (EFSA), Australia/NZ (NHMRC) and WHO/FAO. Your choice is highlighted. Each line names its type (RDA, RNI, PRI, RDI, AI, and so on) and links to its source. Label amounts, with no absorption factors. Where a body sets no value, it says so; no other body's figure is used instead.
Nutrient
Per 100 g raw
Daily amounts, woman 31–50
Protein
1.21 g
US/Canada (your choice)2.63% of 46 g [RDA][source]
WHO2.08% of 58.1 g [safe level][source]0.83 per kg body weight × 70 kgfor top-quality protein (PDCAAS 1.0): "The value accepted for the safe level of intake is 0.83 g/kg per day, for proteins with a protein digestibility-corrected amino acid score value of 1.0. (PDF p. 256)"
Fiber
1 g
US/Canada (your choice)4% of 25 g [AI][source]total fiber
WHO0.629–1.89% of 19.6–58.8 mg, depends on diet [RNI][source]depends on diet: WHO gives one figure for each level of iron absorption from the diet (15%, 12%, 10% and 5%)
WHO3.27–10.7% of 3–9.8 mg, depends on diet [RNI][source]depends on diet: WHO gives one figure for each level of zinc absorption from the diet (high, moderate and low)
Other nutrients with a daily amount
Nutrient
Per 100 g raw
Daily amounts, woman 31–50
Vitamin D
0 µg (assumed zero by USDA)
US/Canada (your choice)0% of 15 µg [RDA][source]every food is by USDA
Australia/NZ0.4% of 2 g [SDT][source]NHMRC public consultation on sodium closed 30 Sep 2026; values may be revisedadequate intake (): 460–920 mg/day; shown for reference, no %
No absorption figure has been sourced for this food yet, so label amounts are shown unadjusted.
What comes with it: what the carbohydrate becomes
Per 100 g as eaten, from UK CoFID 2021 (McCance and Widdowson). CoFID gives starch and sugars as monosaccharide equivalents, so half of sucrose counts as glucose and half as fructose. This is a different measure from USDA's “carbohydrate, by difference” in the table above, and the two are never mixed.
zucchini
Most of the carbohydrate in raw zucchini is sugar. 100 g ends up as about 1 g of glucose and about 1.3 g of fructose, plus traces of sucrose.
Becomes glucosefree glucose + starch + half of sucrose
UK CoFID 2021 13-628: Courgette, boiled in unsalted water [source]
What comes with it: compounds
Amounts for 100 g of each preparation. Thresholds are worked out for 70 kg body weight.
(bitter courgettes only)
Dose
raw: not in totals: no amount in the source data; explainer onlyboiled: not in totals: no amount in the source data; explainer only
Cooking
Heat-stable: cooking does NOT destroy them. [source]
Threshold
AdviceBfR: taste raw first and don't use if bitter. No .
Effect
'Toxic squash syndrome': vomiting and diarrhoea; a man died in Germany in 2015 after a stew of bitter home-grown courgettes. French series 2012–16: 353 patients, no deaths. Case report
0 entries for this food are hidden pending verification. They are never shown with a value until checked.
Acceptable daily intake: the amount you could eat every day for life without appreciable risk, set by food-safety bodies.
LOAEL
Lowest dose at which any harmful effect was seen in studies.
MOE
Margin of exposure: how many times smaller your dose is than the lowest harmful dose. Bigger is safer. EFSA says what margin it counts as 'no concern'.
RAE
Retinol activity equivalents: vitamin A counted as what your body can actually make from it.
RDA
Recommended Dietary Allowance: the US daily amount that covers the needs of nearly all healthy people of a given age and sex.
AI
Adequate Intake: the US daily amount used when there isn't enough evidence to set an RDA.
Heme iron
The form of iron in meat and fish; absorbed much better than the nonheme iron in plants.
Nonheme iron
The form of iron in plants; less well absorbed, and easily blocked by tea, cocoa and phytate.
Provitamin
Something your body can turn into a vitamin, like beta-carotene into vitamin A.
Glycoalkaloids
Natural pesticides made by potatoes, tomatoes and eggplants.
Oxalate
A compound that binds calcium; high in spinach; linked to kidney stones in large studies.
Nitrate
Found naturally in leafy and root vegetables; has a safe daily limit, but is also studied for lowering blood pressure.
Glucosinolates
The cabbage family's defense chemicals. When the plant is chewed or cut, they break down into sharp-tasting mustard oils.
Goitrin
A breakdown product of progoitrin, found in the cabbage family. At high doses it reduces how much iodine the thyroid takes up.
Phytate
A plant's phosphorus store, mostly in seeds. It binds zinc and iron in the gut, so less of them is absorbed.
Lectin
A protein that binds sugars. The lectin in raw kidney beans causes severe vomiting; thorough boiling destroys it.
Furanocoumarins
Compounds in celery, parsnip and their relatives that make skin burn more easily in sunlight.
Cucurbitacins
Very bitter defense compounds of the squash and cucumber family. Bred out of store-bought varieties; not destroyed by cooking.
Agaritine
A natural compound in white button mushrooms. Cooking reduces it; long-term mouse studies are mixed.
Evidence grade
How strong the proof is: a regulator's assessment and human trials count most; animal and cell studies least.
Assumed zero
USDA didn't measure it; it assumes none is there (for example vitamin B12 in plants).
ARfD
Acute reference dose: the most you can take in within one day, or a single meal, without appreciable health risk, set by food-safety bodies.
Cyanogenic glycosides
Plant compounds that release hydrogen cyanide when the plant's cells are crushed or chewed. Found in cassava, lima beans, bitter almonds and apple seeds.
Amygdalin
The cyanogenic glycoside in almonds and apple seeds. Bitter almonds contain hundreds of times more than sweet ones.
Isoflavones
Soy compounds that act weakly like the hormone estrogen.
