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Davis

Davis, California

Sunday, April 21, 2024

Sustainable Agriculture: Eat by Color

Not all vegetables are created equally. We are encouraged to eat five servings of fruit and vegetables daily, which seems pretty ambitious. As an overloaded, stressed-out college student, feeding myself three meals a day is a feat in itself. What if I told you, though, that eating one serving of certain vegetables would give you the same amount of nutrients of five servings of another?

Such is the case with spinach and iceberg lettuce. It is surprising how popular iceberg lettuce is considering how few redeeming qualities it has. Save for crunchiness, iceberg lettuce is neither tasty nor nutritional. One serving of spinach has over five times the plant nutrients, or phytonutrients, that iceberg lettuce has. But what are phytonutrients, and why should we like them?

Phytonutrients are chemicals within plants that have multiple health benefits. We are unknowingly familiar with them, because phytonutrients often give foods their flavor. Take for example carotenoids, a class of phytonutrients that act as antioxidants. Antioxidants are known to help protect us against cancer. Without a lab coat, though, how can an average person discern the amount of phytonutrients in produce?

By color! Fruits and vegetables with deeper, more vibrant colors indicate more nutritional value. Spinach, a deeply green hue, is obviously more exciting than iceberg lettuce, a half-hearted attempt at yellow green.

The same rule can be applied to different varieties of the same vegetable. There are hundreds of potato varieties grown worldwide, and the nutritional content of each varies. For example, purple potatoes can have over 20 times the amount of phytonutrients that yukon gold potatoes have. I don’t want to embarrass russet potatoes, the most widely used potato in the U.S., but I will. If phytonutrients were weapons, a russet potato would be holding a toothpick while battling a purple potato’s sledgehammer. Purple potatoes have over a hundred times the phytonutrients that russet potatoes have.

Once we understand the nutritional differences of vegetables, we start to ask why we are filling our stomachs with nutritionally weak food when better alternatives exist. This brings us to the histories of domestication of our vegetable crop plants.

The story starts thousands of years ago when indigenous people, mostly in Mesoamerica, began selecting wild plants that best served their needs. They selected for larger edible portions of plants, the ease of collecting, taste and suitability to their growing season. Some argue that the sweet tooths of early domesticators led to the nutritionally deficient produce we have today. But that still doesn’t explain the iceberg lettuce.

The fact is that modern plant varieties are developed for the rigors of the industrial food system, not for taste or nutritional value. The tomatoes that Davisites see strewn along the edge of Highway 113 come summer taste nothing like the heirlooms grown in the plots of community gardens. Those roadside tomatoes were bred to withstand the beating of machine harvest and trucks that transport them by the ton. The same is true for other fruits and vegetables. The flavors of our grandparents’ era are increasingly shoved aside for produce ripened by ethylene gas and flown across continents.

If we are concerned with the nutritive value of our food, we find that there has been a steady decline in the quality of vegetables starting from the 1940s — a convenient starting point as chemical fertilizers were developed in the same decade. A study done by a researcher at the University of Texas, Austin confirms that our obsession with increased yields has come at the sacrifice of nutritional substance.

In other words, our grocery carts and stomachs are filling up, but we aren’t getting a better value. Perhaps modern plant breeders should take some advice from my mom by adopting the ethic of “Quality, not quantity.”

 

To agree or disagree with ELLEN PEARSON’S mom, email erpearson@ucdavis.edu.

 

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