Nobody, going by the sources. The one documented caution in microgreens safety warnings is not that the food is risky. It is about vitamin K and one type of medicine. UF Health tells people who take a blood-thinning medicine, such as warfarin, that they may need to limit vitamin K foods. That is a limit rather than a ban, and it covers a whole category of food, not this one crop.
That guidance stops right there, and so should anyone repeating it. There is no mechanism given, no milligram figure and no daily ceiling. No serving size and no safe swap either. So if a page hands you an exact vitamin K number for a tray of sunflower shoots, the number came from somewhere else, and you have no way to check it.
The link between microgreens and warfarin runs through vitamin K, and nothing in this research goes past that point. Some varieties do carry more than others. USDA's Agricultural Research Service measured 25 commercial varieties and put garnet amaranth at the top for vitamin K. That is a ranking, not an amount. You cannot turn a first-place finish into a portion size.
Raise it with the prescriber who set your dose before you change what you eat. The advice on record is to limit vitamin K foods, not to cut them out, and no source here gives a safe amount for you to work from on your own.
Most people land on this question expecting a list of groups: pregnancy, young children, anyone with a weak immune system. No source in this research names any of them. What the research does cover is the plain fact that this crop gets eaten raw, which puts the weight on how it was grown and how well it was washed.
The real microgreens safety warnings are about growing and washing, so keep garden soil, manure and compost out of your mix. Any of the three can harbor bacteria, and there is no cooking step here to fall back on. Then rinse the greens well before they go on a plate. Two habits, and between them they do more for your day to day safety than any list of people who should skip the food.
Nitrate is the other number that gets tossed around, and it swings hard by species. A 2025 analysis in Scientific Reports measured 636.41 mg per kg in red beet and found none at all in pea. The paper reports that spread and stops. It names no group who should steer clear of a species, and neither will I.
Ask your prescriber in a way they can answer. Not is this food safe, but here is what I want to eat most weeks, does my dose still hold up. Bring the variety and how often you plan to eat it. That is a short conversation, and it beats dropping a food you like on the strength of a guess you read online.
The honest answer on microgreens vitamin K fits in two lines. Talk to the person who wrote your prescription, and let them make the call instead of cutting foods on your own. And no source here names a group that is medically advised to avoid this crop outright. What sits on record is a limit, not a cutoff, and these greens are one item on a long list.
Read the full article: Microgreens: What Science Says and How to Grow
