The primary nutritional contribution of organic greens are fiber; minerals like potassium, magnesium, & iron; and antioxidants like Vitamin C and those associated with pigments, such as the carotenoids and flavones/flavonoids.
Dietary greens are also important for what they are not – they can take the place of the processed foods laden with unhealthy fats, refined carbohydrates and chemicals and devoid of quality nutrition that dominate so many of our diets.
The USDA National Nutrient Database for Standard Reference is the major source of food composition data in the United States. It provides the foundation for most food composition databases in the public and private sectors. Release 26 contains data on 8,463 food items and up to 150 food components. We used this database to generate the nutrition data we present on these pages.
Nutrition data is presented for a 100 gram standardized quantity of food, and other units of measure can be chosen. Numbers are reported to the precision presented in the USDA database. A zero is a zero, and a blank means that a number was not reported but does not necessarily mean that the nutrient is not present. Spinach is the best-studied of the greens presented.
Recommended intakes of nutrients vary by age and gender and are known as Recommended Dietary Allowances (RDAs) and Adequate Intakes (AIs). However, one value for each nutrient, known as the Daily Value (DV), was developed by the U.S. Food and Drug Administration (FDA) for use in food labeling. A DV is often, but not always, similar to one’s RDA or AI for that nutrient.
You will see a column in this website’s Nutrient output that shows the percentage of DV that a particular food or group of foods provides.You will also see that nutrient names in that output link to pages that explain the function of that nutrient. We have focused initially on the nutrients of particular relevance to greens but will be expanding the number of nutrients with explanations as time goes on.
We have presented the nutrient composition of raw and cooked greens, where appropriate. The USDA database contains values for most cooked greens as boiled, without salt. This is a rather extreme way to cook these greens, but comparing the raw to cooked is interesting.
Cooking greens reduces the amounts of some nutrients, particularly those degraded by heat, like vitamin C, or lost in discarded water, like Vitamin C and minerals. Cooking also increases the bioavailability of other nutrients, and in many cases dramatically increases the quantity of greens and thus nutrients consumed. One pound or ten packed cups of fresh spinach will yield about one cup of cooked spinach, a ratio of about 10:1. One cup of raw spinach weighs about 30 grams while a cup of cooked spinach weighs 180 grams. Other greens have similar relationships between raw and cooked quantities and weights.