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Veganism and the Issue of Protein

Can a vegan diet provide adequate protein for sound human health? Absolutely. Unlike animal protein, plant-based protein sources contain healthy fiber and complex carbohydrates. Animal products are often high in artery-clogging cholesterol and saturated fat, and the consumption of animal protein has been linked to some types of cancer. There’s no need to eat animal products to maintain good health, as a quick study of the facts about plant protein and nutrition shows.

The Importance of Protein

Our bodies—our hair, muscles, fingernails, and so on—are made up mostly of different kinds of protein that consist of varying combinations of amino acids. In much the same way that the 26 letters of the alphabet can form millions of different words, 20 amino acids serve to form different proteins.

Although half these amino acids can be manufactured by the human body, the other 10 cannot.(1) These “essential amino acids” are easily obtained by eating a balanced vegan diet.

How Much Protein?

As babies, our mothers’ milk provided the protein that we needed to grow healthy and strong. Cow’s milk has about three times the amount of protein found in human breast milk. Once babies start eating solid foods, plant sources can easily provide them with all the protein that they need. Only 10 percent of the total calories consumed by the average human being needs to be in the form of protein.(2) The recommended dietary allowance for both men and women is 0.80 grams of protein for every kilogram (2.2 pounds) of body weight.(3) People with special needs, such as pregnant women, are advised to get a little more. If a vegan eats a reasonably varied diet and consumes a sufficient amount of calories, he or she will undoubtedly get enough protein.

Eating too much animal protein has been linked to the development of endometrial, pancreatic, and prostate cancers.(4,5,6) By replacing animal protein with plant protein, you can improve your health while enjoying a wide variety of delicious foods.

Protein Sources

While virtually all vegan foods contain some protein, soybeans deserve special mention. Soybeans contain all the essential amino acids and surpass all other plant foods in the amount of protein that they can deliver to humans. The human body is able to digest 92 percent of the protein found in meat and 91 percent of the protein found in soybeans.(7) The availability of many different and delicious soy products (e.g., tempeh, tofu, and soy-based varieties of hot dogs, burgers, and ice cream) in grocery and health-food stores suggests that the soybean, in its many forms, can accommodate a wide range of tastes.

Other rich sources of non-animal protein include legumes, nuts, seeds, food yeasts, and freshwater algae. Although food yeasts, such as nutritional yeast and brewer’s yeast, do not lend themselves to being the center of one’s diet, they are extremely nutritious additions to many dishes, including soups, gravies, breads, casseroles, and dips. Most yeasts are 50 percent protein.(8)

Percentage of Calories From Protein (Value Per 100 Grams Edible Portion)

From the U.S. Department of Agriculture’s National Nutrient Database for Standard Reference, 2009.(9)

Fruits
Apple      2%
Banana      5%
Cantaloupe    10%
Grapefruit     8%
Grapes      4%
Honeydew melon    6%
Orange      8%
Papaya      6%
Peach      9%
Pear      3%
Pineapple     4%
Strawberry     8%
Tangerine     6%
Tomato   19%
Watermelon     8%

Grains
Barley    14%
Brown rice     8%
Buckwheat   15%
Millet    12%
Oatmeal   17%
Rye    18%
Wheat germ   26%
Wheat (hard red)  15%
Wild rice   16%

Legumes, Raw
Garbanzo beans  21%
Kidney beans   58%
Lentils    34%
Lima beans   24%
Navy beans   37%
Soybeans   35%
Split peas   29%

Nuts and Seeds
Almonds   15%
Cashews   13%
Filberts     9%
Peanuts   18%
Pumpkin seeds  18%
Sesame seeds   12%
Sunflower seeds  16%
Walnuts (black)  15%

Vegetables, Raw
Artichokes   28%
Beets    15%
Broccoli   33%
Brussels sprouts  31%
Cabbage   24%
Cauliflower   32%
Cucumbers   17%
Eggplant   17%
Green peas   27%
Green pepper   17%
Kale    26%
Lettuce    36%
Mushrooms   56%
Mustard greens  41%
Onions      9%
Potatoes   18%
Spinach   50%
Turnip greens   20%
Watercress   84%
Yams      5%
Zucchini   30%

What You Can Do

Going vegan opens up a whole new world of tasty foods and flavors. There are vegan alternatives to almost every animal food that you can think of—from soy sausages and “fib ribs” to phony bologna, Tofurky jerky, and mock lobster. A vegan diet can—and should—be full of a wide variety of delicious foods, plus you’ll save a lot of animals from the misery of factory farms. 

References
1) University of Arizona, Department of Biochemistry and Molecular Biophysics, “Amino Acids Problem Set,” The Biology Project, 25 Aug. 2003.
2) Paula Kurtzweil, “‘Daily Values’ Encourage Healthy Diet,” U.S. Food and Drug Administration, 2003.
3) National Academy of Sciences, Food and Nutrition Board, “Dietary Reference Intakes for Energy, Carbohydrates, Fiber, Fat, Protein, and Amino Acids (Macronutrients),” 2005: 589.
4) Reuters, “Animal Protein and Fat Raise Endometrial Cancer Risk,” 21 Mar. 2007.
5) June M. Chan et al., “Pancreatic Cancer, Animal Protein and Dietary Fat in a Population-Based Study,” Cancer Causes and Control 18 (2007): 1153-67.
6) N.E. Allen et al., “Animal Foods, Protein, Calcium and Prostate Cancer Risk: The European Prospective Investigation Into Cancer and Nutrition,” British Journal of Cancer 98 (2008): 1574-81.
7) Gertjan Schaafsma, “The Protein Digestibility-Corrected Amino Acid Score,” Journal of Nutrition 130 (2000): 1865S-1867S.
8) U.S. Department of Agriculture, National Nutrient Database for Standard Reference, “Leavening Agents, Yeast, Baker’s, Active Dry,” Nov. 2009.
9) U.S. Department of Agriculture, Agricultural Research Service, “Nutrient Data Laboratory,” 11 Nov. 2009.
 

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