Читать книгу Nutrition For Dummies - Carol Ann Rinzler - Страница 13

Each of the nutrients in food fall into one of two distinct groups, macronutrients and micronutrients:

 Macronutrients (macro = big): Protein, fat, carbohydrates, and water

 Micronutrients (micro = small): Vitamins and minerals and a multitude of other substances

What’s the difference between these two groups? The amount you need each day.

Your daily requirements for macronutrients generally exceed 1 gram. An ounce of solid material, such as chicken, has 28 grams, and an ounce of liquid, such as water, has 30 grams. To give you an idea of how that translates into nutrient requirements, the average man needs about 63 grams of protein a day (slightly more than 2 ounces), and the average woman needs about 50 grams (slightly less than 2 ounces).

And remember: That’s grams of protein, not grams of a high-protein food such as meat, fish, or poultry.

For example, the USDA National Nutrient Database for Standard Reference (http://ndb.nal.usda.gov), one of the ten thoroughly reliable sources listed in Chapter 27, provides the following information for grams of meat versus grams of protein:

 Chicken: 3 ounces/86 grams breast meat (no bones, no skin), roasted, provides 26.7 grams/0.96 ounces protein

 Lean ground beef (7% fat): 4 ounces/113 grams provides 23.6 grams/0.86 ounces protein

 Canned salmon: 3.5 ounces/100 grams provides 19.68 grams/0.70 ounces protein

Your daily requirements for micronutrients are much smaller. Consider vitamins. The Recommended Dietary Allowance (RDA) for vitamin C is measured in milligrams (1/1,000 of a gram), while the RDAs for vitamin D, vitamin B12, and folate are even smaller, measured in micrograms (1/1,000,000 of a gram). For more about the RDAs, including how they vary for people of different ages, check out Chapter 3.