The three species measured in a 2015 analysis in the International Journal of Molecular Sciences ran 81.74% to 89.32% water. What got tested behaves like a garnish, not like a serving of vegetables. People call edible flowers healthy food, and the numbers back a modest version of that. You get color, you get flavor, and you pay close to nothing in calories for either one. That is the honest answer, and it is a small one.
The edible flower nutrition figures stay small down the whole list. Energy ran 21.44 to 28.84 kcal per 100 g. Total fat sat between 0.32% and 0.41%, and protein came in at 1.32% to 2.84%. Fiber was the one line that stood up at all, ranging from 4.51% to 10.11% by fresh weight. None of it is a reason to eat flowers. None of it is enough to change your day either.
Water content decides the rest. At close to 90% water, a petal does about what a cucumber slice does on your plate. Those percentages also sit on a 100 g base, and 100 g of petals is a startling pile of flowers. You would need a full colander to get there. A scatter of nasturtium blossoms over your salad is a small fraction of that. Scale the fiber down to a portion that size and you are left with a rounding error.
The same analysis identified 39 phenolic compounds across the three species. Flavonols were the largest group. That work is where most claims about antioxidants in flowers start. But an antioxidant assay tells you what a plant extract does in a glass tube. It does not tell you what happens inside a person eating a salad. The researchers said as much themselves. The real contribution in the body is still under discussion.
The gap between those two things is wide. Measured antioxidant activity has come in 56 to 1416 times higher than the identified phenolics predicted. Read that as a sign the chemistry is far from mapped. It is not proof that the flowers do more for you. A number nobody can explain yet is not a health benefit you can bank on. It is a to-do list for the next round of lab work.
One figure here is worth chasing. Nasturtium leaves carry about 10 times the vitamin C of lettuce, and that is a real difference you can put to use. The leaves taste peppery, close to watercress, and they stack into a sandwich the way arugula does. Note that the figure is for the leaves, not the petals. Petals are what you put on the plate, so the part with the good number often stays out in the garden. Pick a few leaves along with the blossoms and you get both.
All of it covers three plants and nothing else. Those are nasturtium (Tropaeolum majus), marigold (Tagetes erecta), and paracress (Spilanthes oleracea). That study reports no figures for violets, or for borage, or for the dozens of other kinds sold as edible. A pansy was never part of it. So treat a broad claim about flowers with care. It is three measured species doing the talking for a whole big group.
So use flowers for what they do well. They make your plate look better, they bring pepper or citrus or a clean bitterness, and they add almost no calories doing it. Calling edible flowers healthy is fair in that narrow sense, and it stops right there. Grow the ones you like the look of, and eat the ones you can name. Let the greens and the beans on your plate carry the nutrition. A garnish that is 89% water was never going to.
Read the full article: Edible Flowers: What to Eat, What to Skip
