Do Microgreens Really Have 40 Times the Nutrients?

Short answer: the number is real, and it describes one nutrient in one crop. Red cabbage microgreens were measured at more than 40 times the vitamin E of mature red cabbage. That is a genuine laboratory result from a genuine study.

Then it escaped. "Microgreens have 40 times the nutrients" is now the most repeated sentence in this hobby, and as a statement about the category it is wrong in both directions. Some crop-and-nutrient pairs come in far above 40, one at about 260. And for at least one compound, the mature plant is the more concentrated of the two.

This page is about what the study actually measured, why a single multiplier cannot exist, and the two traps that make these numbers look bigger than what ends up on your plate.

Where the number came from

One paper, and it is a good one. Researchers assayed 25 commercially grown microgreens in a laboratory food analysis and compared them against published values for the mature crop. No people, no animals. Plants on a bench.

It is worth being clear what that means before anything else: this is a measurement of chemicals in a vegetable. It is not a health outcome, and it has never been shown to change anybody's blood work. That is a separate question we cover on blood sugar, inflammation and gut health, and the answer in all three is that nobody has tested it.

What the study is excellent for is telling you which crop to grow if you want a particular nutrient. That is a real, useful answer, and it is not the one the multiplier gives you.

What the study actually found, pair by pair

Here are the comparisons the paper made between a microgreen and its own mature version. Read the right-hand column down the page.

Six comparisons in one study, and the ratios run from about 3 to about 260. The famous 40 is the second row, and it is neither the highest nor typical. It is simply the one that got repeated.

No single multiplier can describe a spread that covers two orders of magnitude. Picking 40 out of it is not a summary, it is a selection.

The official number is five, not forty

This is the part that surprises people. USDA, whose own researchers did the work, summarised it as microgreens carrying about five times the vitamins and carotenoids of mature leaves, on average, across the 25 crops.

An average across 25 crops is not a promise about any one of them. It is a description of a spread, and you have just seen how wide that spread is. Applying it to the crop in front of you is the same error as applying 40, only quieter.

The crop that came in lowest, and why

The most useful single result in the study is not in that table at all, because it is not a microgreen-against-mature comparison. It is a microgreen against itself.

Golden pea tendrils grown without light had the lowest beta-carotene of all 25 crops, at 0.6 mg/100 g, and the authors specifically note they carried much lower vitamin and carotenoid levels than pea tendrils grown in light. Same species, same seed, same laboratory. The growing method alone put one of them at the bottom of the study.

Carotenoids are made in response to light. Grow a crop in the dark and you get a paler, sweeter, more tender shoot with less of them. That is a real trade and plenty of growers make it on purpose.

Which tells you the multiplier is not even a property of the crop. It is a property of the crop as you grew it. Two trays of the same seed, one blacked out longer than the other, are not the same food, and no number printed on a bag can know which one you produced.

Minerals tell a different story, and a smaller one

Vitamins and carotenoids are where the dramatic numbers live. Minerals behave nothing like that.

A separate analysis found compost-grown broccoli microgreens averaged 1.73 times mature broccoli across eight minerals: phosphorus, potassium, calcium, magnesium, manganese, iron, zinc and sodium.

Not 40. Not even 5. About 1.7, and the study says explicitly that the result depends on how the crop was grown, with hydroponic cultivation changing both the size and the direction of the difference against compost.

So the honest version is: young brassica leaves are modestly more mineral-dense than the grown head, sometimes, depending on the medium.

Sometimes the same crop goes both ways at once

The clearest single demonstration that "more nutrients" is not a coherent claim comes from broccoli glucosinolates, the compounds behind most of the health interest in this crop.

Comparing broccoli microgreens against mature florets and leaves, the microgreens carried more total aliphatic glucosinolates, while the mature tissue was more concentrated in glucoraphanin specifically, which is the one that becomes sulforaphane.

One measure up, another down, in the same crop, in the same paper. "Microgreens have more" does not survive contact with that, and neither does "mature has more".

Two traps that make the numbers look bigger

Most wildly inflated figures you see come from one of these, and they are easy to spot once named.

Trap one: dry weight against fresh weight

Fresh microgreens are mostly water. Dry the sample and every concentration per gram rises sharply, because you removed the water and not the nutrient.

Papers legitimately report both. Broccoli microgreen glucosinolates get quoted at 28.1 micromoles per gram of dry weight, while a classic measurement of mature broccoli florets is 1.08 micromoles per gram of fresh weight. Set those side by side and you appear to have a 26-fold difference. You do not. You have two different units and no comparison at all.

If a ratio does not tell you the units on both sides, it is not a ratio.

Trap two: concentration against serving

This is the bigger one, and it is the reason the multiplier matters much less than it sounds.

Every figure above is per 100 g. Nobody eats 100 g of microgreens. The human feeding study on this crop used a 16 g serving, and that is a generous handful, not a garnish.

The left column is measured and published. The other three columns are our own arithmetic on those figures, using the 16 g serving from the human study.

Look at what that does to the story. On vitamin C, a handful of red cabbage microgreens is worth roughly a small bowl of shredded red cabbage, which is good and unremarkable. On beta-carotene, the same handful is worth an amount of mature red cabbage nobody would ever eat, which is genuinely striking. And the dark-grown pea tendrils, from a serving the same size, deliver about one nineteenth of the beta-carotene the red cabbage microgreens do.

Same crop family, same study, same serving. Three completely different answers. That is what a category-wide multiplier hides.

How a real measurement became a slogan

Every step keeps the previous sentence's authority while widening what it covers. Nobody has to lie for this to happen.

So what should you take from it

The practical version is short. Grow for the crop, not for the category. If you want carotenoids and vitamin C, red cabbage and cilantro measured best of the 25 and they are two of the easiest things to grow. If you want vitamin E, green daikon radish led that group. If you are blacking a crop out for tenderness, accept that you are trading away some of the pigment compounds, because that is a real trade rather than a rumour.

The ranges, if you want the whole picture

For completeness, this is the spread across all 25 crops. The width of each range is the real finding of the study.

Vitamin C spans a factor of seven. Vitamin E spans a factor of eighteen. Beta-carotene spans a factor of twenty. The variation between crops is bigger than most of the microgreen-to-mature ratios being advertised, which is the whole argument on one line.

So is it true

It is true about one nutrient in one crop, and it is not true about microgreens.

What is fair to say: microgreens are young vegetables, several of them are genuinely nutrient-dense, a few crop-and-nutrient pairs are dramatically higher than the grown plant, minerals are modestly higher at best, at least one compound is more concentrated in the mature plant, how you grow the crop moves the number as much as which crop you chose, and all of it is a measurement of chemistry rather than a measurement of anybody's health.

What is not fair to say is any sentence that starts "microgreens have" and ends in a number.

What would settle it

Matched pairs, grown and measured together. The same cultivar raised to microgreen stage and to maturity under identical conditions, assayed in the same laboratory, reported on both a fresh-weight and a dry-weight basis, for a defined list of nutrients, across a decent number of crops.

Almost none of the multipliers in circulation come from a design like that. They come from a microgreen measured in one study set against a mature value from a database compiled somewhere else by somebody else, which is a reasonable thing for researchers to do and a poor foundation for a slogan.

Sources

• Xiao et al., 2012, vitamin and carotenoid concentrations in 25 microgreens - the source of the "40 times" figure. Vitamin C 20.4 to 147.0 mg/100 g fresh, beta-carotene 0.6 to 12.1, lutein and zeaxanthin 1.3 to 10.1, phylloquinone 0.6 to 4.1 micrograms/g, alpha-tocopherol 4.9 to 87.5 mg/100 g; red cabbage vitamin C 147.0 against 24.4 mature, beta-carotene 11.5 against 0.044, lutein and zeaxanthin 8.6 against 0.3, vitamin E more than 40-fold mature; cilantro beta-carotene 11.7 at about threefold and lutein and zeaxanthin 10.1 against 0.9; and the dark-grown golden pea tendrils at 0.6 mg/100 g beta-carotene, below light-grown.
• USDA ARS summary of that assay and the publication record - the "about five times on average" statement, and the note that levels varied widely by crop.
• Weber, 2017 - compost-grown broccoli microgreens averaging 1.73 times mature broccoli across eight minerals, with the study's own statement that the result depends on growing method and that hydroponic cultivation changed both magnitude and direction.
• Broccoli microgreen and mature comparison - higher total aliphatic glucosinolates in the microgreens, with the mature tissue more concentrated in glucoraphanin.
• Fahey et al. - mature broccoli florets at 1.08 micromol glucoraphanin per gram FRESH weight, the figure most often set against dry-weight microgreen numbers.
• Fresh broccoli microgreens in 11 people - the 16 g serving used for the per-serving arithmetic on this page. The serving-size and matching-amount columns are our own arithmetic on the published concentrations, not figures from any study.