Dear Science,
Why are oranges orange?
Dear Navel Gazer,
Oranges are orange because of anthocyanins. These compounds serve an analogous role to melanin in human skinâprotecting plant tissues from UV damage. The blue of blueberries, the black of blackberries, and the grape of grapes is caused by anthocyanins stuffed into the tissues. Anthocyanins are part of a broader family of plant molecules, including flavonoids and carotenoidsâall powerful antioxidants grabbing up DNA-damaging free radicals created by sunlight and metabolism. Eating these compounds helps protect against cancer, heart disease, and stroke.
How much of these compounds do we eat? Grab some packaged food and run down the label. The macronutients, the carbohydrates, the fats, and the proteins are right there in fat black type. When scientists first started ripping apart food to figure out what chemically makes it work, the macronutrients were the first discoveries. Make a slurry with the right amount of sugar, fat, and protein, and everyone would be dandy, right? Viva Fritos. But keep reading the label and you'll see the micronutrient content, often with a sad note that begins "not a significant source of...." Processing foods strips them of their micronutrients, even when preserving macronutrients. Once the micronutrients were discovered, cataloged, and isolated, they could be stuffed back into processed foods or compressed into pill form. Hence, Hi-C (with lots of vitamin C) and various foul-tasting breakfast cereals. Where are the anthocyanins? Replaced with various dyes.
Anthocyanins are only now being discovered and cataloged. This is why you can't survive on Twinkies, Total, and Tang alone. Multivitamins, regardless of how "complete" they are, still cannot replace eating five or six servings of fruits and vegetables per day.
Dear Science,
Why is poop brown?
Dear Shit Talker,
Rusting, worn-out bits of red blood cells make poop brown. Red blood cells have a tough life, continuously crushed through tiny vessels and subjected to blasts of damaging oxygen. As the cells wear out, the hemoglobinâoxygen carrying, iron containing, and highly toxicâhas to be disposed somewhere. Ever resourceful, the liver grabs up the decaying bits of hemoglobin and converts them into bile salts. With every meal, particularly a greasy extravaganza, the liver drops the bile salts into the intestines, where they bind up fats and allow them to enter the body. The extra bile continues down to the large intestines, where a multitude of bacteria devours what remainsârusting the iron originally in the hemoglobin. Hence, brown.
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