Estimating Healthfulness by Eye There’s a useful guideline for estimating the relative healthfulness of vegetables and fruits: the deeper its color, the more healthful the food is likely to be The more light a leaf gets, the more pigments and antioxidants it needs to handle the energy input, and so the darker the coloration of the leaf For example, the lightcolored inner leaves of lettuce and cabbage varieties that form tight heads contain a fraction of the carotene found in the darker outer leaves and in the leaves of more open varieties Similarly, the dark leaves of open romaine lettuce contain nearly 10 times the eye-protecting lutein and zeaxanthin of the pale, tight heads of iceberg lettuce Other deeply colored fruits and vegetables also contain more beneficial carotenoids and phenolic compounds than their pale counterparts Their skins are especially rich sources Among the fruits highest in antioxidant content are cherries, red grapes, blueberries, and strawberries; among vegetables, garlic, red and yellow onions, asparagus, green beans, and beets Fiber Fiber is defined as the material in our plant foods that our digestive enzymes can’t break down into absorbable nutrients These substances therefore aren’t absorbed in the small intestine, and pass intact into the large intestine, where some are broken down by intestinal bacteria, and the rest are excreted The four main components of fiber come from plant cell walls (p 265) Cellulose and lignin form solid fibers that don’t dissolve in our watery digestive fluids, while pectins and hemicelluloses do dissolve into their individual molecules Minor components of fiber include uncooked starch and various gums, mucilages, and other unusual carbohydrates (e.g., mushroom chitin, ...blueberries, and strawberries; among vegetables, garlic, red and yellow onions, asparagus, green beans, and beets Fiber Fiber is defined as the material in our plant foods that our digestive enzymes can’t break... down into absorbable nutrients These substances therefore aren’t absorbed in the small intestine, and pass intact into the large intestine, where some are broken down by intestinal bacteria, and the rest are excreted The four main components of fiber come from... hemicelluloses do dissolve into their individual molecules Minor components of fiber include uncooked starch and various gums, mucilages, and other unusual carbohydrates (e.g., mushroom chitin,