Most of the fruits and vegetables we eat in Singapore travel a long way by lorry and plane to reach us. We import more than 90% of our fresh produce¹, and when it gets here, it can sit on supermarket shelves or in non-refrigerated storage for days before coming home with us.
And if you're like me, those same vegetables sometimes end up wilting in my fridge when I forget about cooking them, only for me to pull them out in a panic days later from the bottom of the drawer, wet and slimy.
Because many of our vegetables in Singapore are harvested a long time before we eat them, I've often wondered about the nutrient loss implications post harvest, and how microgreens, which are harvested minutes before we eat them, as well as purchasing locally grown farm produce, can step in as a partial solution.
At home, we usually have 2 Microbeds growing at the same time with different varieties of microgreens, and while they are not a replacement for mature vegetables, they provide a significant source of our daily nutritional intake.
To discover what the science says about nutrient loss in vegetables post harvest and how the power of nutrient dense microgreens can compensate, we thread together 3 of the most authoritative, peer reviewed studies in this space.
Study 1: The Post Harvest Nutrient Loss study by Penn State
In one of the landmark studies by Penn State (2004)², researchers found that spinach kept at 4°C/39°F after harvest retained only 53% of its folate and carotenoids after 8 days. At higher temperatures the loss accelerates, and at 20°C/68°F it took only 4 days to lose half of these nutrients. The study also found that carotenoids behaved similarly, although individual carotenoids differed.
While the study does not go all the way up to Singapore’s typical ambient temperatures (26-32°C), the striking finding is that the time required to lose roughly half the folate became dramatically shorter as temperature increased.
Crucially, the study also found that an attractive appearance does not guarantee that the spinach is still rich in nutrients. Spinach can still look fresh while nutritionally depleted.
Unfortunately, even when we do everything right (buy fresh vegetables, refrigerate them quickly, cook them as soon as possible), the supply chain has already done its damage, especially if the vegetables were not refrigerated during transport by lorry or plane, and were purchased at the wet market or were unchilled on supermarket shelves.
Study 2: The Structural Decline in Food Quality study by Bhardwaj et al
Post harvest nutritional loss is only part of the story, as studies like the one by Bhardwaj et al (2024)³ have found a significant decline in food quality and a decrease in a wide variety of nutritionally essential minerals and compounds in fruits, vegetables, and grains over the past 60 years.
The causes identified include a preference for less nutritious high yielding varieties and 'cash crops' over more traditional nutrient intense crops, soil depletion, excessive use of pesticides and agrochemicals, chaotic mineral nutrient application, elevated atmospheric carbon dioxide (affecting the availability of nutrients in soil) and the broader shift from natural to chemical farming.
So we face a compounding problem: Today's vegetables start out less nutritious than those of previous generations, and then we lose a significant portion of what remains during long distance transportation and storage.
"Today's vegetables start out less nutritious than those of previous generations, and then we lose a significant portion of what remains during long distance transportation and storage."
The Benefits of Nutrient Dense Microgreens
Microgreens address both problems at once, because (1) they're harvested and eaten almost immediately, bypassing long supply chains; and (2) research has found that microgreens consistently outperform their mature counterparts in nutrient density.
The science on the nutrient density of microgreens is both stunning and incredibly compelling.
Study 3: USDA/University of Maryland study by Xiao et al (2012)
The landmark USDA/University of Maryland study by Xiao et al (2012)⁴ analysed 25 commercially grown microgreen varieties and found they consistently outperformed their mature counterparts in nutrient density, often by 4 to 40 times.
Red cabbage microgreens, for example, contained six times more vitamin C and 69 times more vitamin K than mature red cabbage.
"Microgreens consistently outperformed their mature vegetable counterparts in nutrient density, often by 4 to 40 times."
“Some of the numbers were really, really high,” Xiao (one of the researchers) said of the findings. “We thought it might have been a mistake but we double-checked so many times and there were no mistakes.”
Other more recent studies have found similar results. A recent multispecies microgreen antioxidant study by Balik et al (2025)⁵ examined six microgreen species (broccoli, black radish, red beet, pea, sunflower, and bean) and found strong antioxidant capacity across all of them that surpassed their mature vegetable counterparts.
The case for growing your own microgreens
Together, the studies in this field tell a clear story. Our vegetables are less nutritious than they were a generation ago, and unfortunately they lose a meaningful share of what remains by the time they reach our plates.
Microgreens, grown on your kitchen countertop and harvested minutes before you eat them, offer a completely different proposition. While they are not a full replacement for mature vegetables, they offer concentrated supplementation of the nutrients that our food systems have lost over the years.
"Microgreens are not a full replacement for mature vegetables but they offer concentrated, bioavailable supplementation of the nutrients that our food systems have quietly lost."
Taken together, the research suggests that alongside supplementing our diets with homegrown, freshly harvested microgreens, we should buy locally grown vegetables as far as possible. When the option is available, choose vegetables that have been stored in the chilled rather than ambient sections at the supermarket.
Sources:
¹ SFA's Singapore Food Statistics 2024 report (released June 2025) https://www.sfa.gov.sg/news-publications/newsroom/2025/singapore-food-statistics-2024
² (Study 1) Pandrangi, S., & LaBorde, L. F. (2004). Retention of folate, carotenoids, and other quality characteristics in commercially packaged fresh spinach. Journal of Food Science, 69(9), C702–C707. https://www.researchgate.net/publication/227607217_Retention_of_Folate_Carotenoids_and_Other_Quality_Characteristics_in_Commercially_Packaged_Fresh_Spinach
³ (Study 2) Bhardwaj, R. L., Parashar, A., Parewa, H. P., & Vyas, L. (2024). An alarming decline in the nutritional quality of foods: The biggest challenge for future generations' health. Foods, 13(6), 877. https://www.mdpi.com/2304-8158/13/6/877
⁴ (Study 3, also known as the USDA-University of Maryland study) Xiao, Z., Lester, G. E., Luo, Y., & Wang, Q. (2012). Assessment of vitamin and carotenoid concentrations of emerging food products: Edible microgreens. Journal of Agricultural and Food Chemistry, 60(31), 7644–7651. https://www.researchgate.net/publication/229425323_Assessment_of_Vitamin_and_Carotenoid_Concentrations_of_Emerging_Food_Products_Edible_Microgreens
⁵ (Study 4) Balik, S., Elgudayem, F., Yildiz Dasgan, H., Kafkas, N. E., & Gruda, N. S. (2025). Nutritional quality profiles of six microgreens. Scientific Reports, 15, Article 6213. https://pubmed.ncbi.nlm.nih.gov/39979322/
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