The recommended dietary allowances, or RDA, for protein are listed as total grams of dietary protein, regardless of whether the source is animal or vegetable. Animal and vegetable proteins, however, are different from each other in unique ways. Getting your daily protein from a variety of sources helps ensure that your body gets all the essential amino acids it requires on a daily basis.
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What Proteins Are Made Of
Proteins in food are made of amino acids. Some amino acids, called nonessential amino acids, your body can make -- while others, called essential amino acids, you have to get from your diet, because your body cannot make them. The nonessential amino acids include alanine, asparagine, aspartic acid and glutamic acid. Usually, amino acids such as arginine, cysteine, glutamine, glycine, ornithine, proline, serine and tyrosine are nonessential -- except during periods of illness and stress, notes MedlinePlus. The nine essential amino acids are histidine, isoleucine, leucine, lycine, methionine, phenylalanine, threonine, tryptophan and valine.
Benefits of Eating Animal Protein
Animal proteins such as eggs, meat, chicken, poultry, as well as seafood and dairy products contain all the essential amino acids you need to build proteins within your body. With the exception of dairy foods, most animal-based proteins contain few – if any -- carbs, giving you a high percentage of your total calories from protein. Many protein-rich, animal-based foods such as red meat, egg yolks and dark-meat poultry, are also rich in zinc and heme iron, which is more readily absorbed in your body than the iron in plant-based foods.
Benefits of Eating Vegetable Protein
Getting your protein from plant-based foods such as soy, quinoa, other whole grains, legumes, as well as nuts and seeds, means that you’re more likely to have a lower intake of dietary cholesterol and unhealthy saturated fat. Proteins from soy and quinoa are classified as complete proteins because they contain all essential amino acids, much like the proteins from animal-based foods. A 2010 review in “Nutrition in Clinical Practice” reports that individuals following vegetarian diets have lower body mass indexes, lower blood cholesterol levels and lower blood pressure than non-vegetarians. Although not all plant proteins are complete proteins, you can still obtain all the essential amino acids by eating a variety of plant proteins during your day, notes MedlinePlus.
Drawbacks of Animal and Vegetable Proteins
Drawbacks exist for both animal- and plant-based proteins. Some proteins from animal foods such as high-fat meats and full-fat dairy foods, contain high amounts of saturated fat and dietary cholesterol, which can increase your risk for heart disease when consumed in excess. Many plant proteins contain some, but not all, essential amino acids. Although the National Center for Complementary and Alternative Medicine suggests that eating soy is safe for most people, soy proteins contain isoflavones, which resembles the female hormone estrogen. Pregnant women and those struggling with infertility should limit their intake of soy, according to the November, 2010 issue of “Today’s Dietitian."
Regardless of the source of your dietary protein, your total daily protein needs are based on your gender, size and activity level. The RDA for protein is 71 grams daily during pregnancy and lactation, 46 grams per day for other women and 56 grams of protein daily for men, according to the Institute of Medicine. Physically active adults benefit from a daily consumption of up to 0.91 grams of protein per pound of their body weight, states the International Society of Sports Nutrition.
- Nutrition in Clinical Practice: Nutrition Concerns and Health Effects of Vegetarian Diets
- National Center for Complementary and Alternative Medicine: Soy
- Today’s Dietitian: Shedding Light on Soy
- Institute of Medicine: Dietary Reference Intakes: Macronutrients
- Journal of the International Society of Sports Nutrition: International Society of Sports Nutrition Position Stand: Protein and Exercise
- MedlinePlus: Protein in Diet