The subject of protein intake is an important consideration in our daily diets, especially with the increased interest and practice of Vegetarianism in our society. Vegetarianism is a conscious way of eating that abstains from the intake of any meat products including beef, lamb, pork, fowl, fish and shellfish and follows a diet which includes legumes, fruits, vegetables, grains, nuts, seeds, soy and gluten products with or without dairy products or eggs. Vegetarians may also avoid products that use animal ingredients in manufacturing, including some sugars that are whitened with bone char, cheeses that use animal rennet (enzymes from animal stomach lining), and gelatins, which are derived from the collagen inside animal’s skin, bone, and connective tissue.
Vegetarianism is adopted for many reasons, including ethical, health, religious, political, cultural, aesthetic, or economic, and there are several different variations defined as Vegetarian diets, which include:
- Ovo Vegetarianism, which includes eggs but not dairy products
- Lacto Vegetarianism, which includes dairy products but not eggs
- Ovo-Lacto Vegetarianism, includes animal/dairy products such as eggs, milk, honey
- Veganism, which excludes all animal flesh/products including milk, honey, eggs
- Raw Veganism, which includes only raw products cooked to a specific temperature
- Ovo-Lacto Vegetarianism includes animal/dairy products such as eggs, milk, honey farming the plants
- Buddhist Vegetarianism (aka Su Vegetarianism) which excludes all animal products and vegetables in the Allium Family which includes; onions, garlic, scallions, leeks and shallots
- Macrobiotic diets consist of mostly whole grains and some fish
- Flexitarians are transitional diets moving from reduced animal products to a vegetarian diet
- Pescetarianism diets include fish and shellfish
- Pollotariansim diets include poultry
The health benefits of Vegetarianism are many, including a lower incidence of heart disease, high blood pressure, type 2 diabetes, colon cancer, and obesity, which is attributed to lower saturated fats and cholesterol and the increased intake of fiber naturally found in fruits and vegetables. There is also evidence that vegetarians may have lower rates of osteoporosis, kidney stones, gallstones, and diverticular disease.
Proteins (aka polypeptides) are organic compounds made up of amino acids and enzymes, which are essential parts of all organisms. They participate in virtually every process within our cells and are vital to our metabolism and have structural-mechanical functions that maintain cell shape, cell signaling, immune response, and cell duplication.
The amount of protein required for normal health is variable depending on body weight, age, physical activity, health condition, environment, etc. Generally, protein intake should be equal to protein loss, which is lost in urine, feces, blood, sweat, skin, nails, hair, etc. When protein intake is less than protein lost, it is called negative protein balance, whereas when it the reverse, it is called positive protein balance. Ideally, for healthy adults, a neutral protein balance should be attained. Growing kids, pregnant-lactating women require more protein and, therefore, should be in a positive protein balance. Other conditions that require positive balance would be people recovering from illness, increased secretion of insulin, growth hormone, or testosterone.
Most microorganisms and plants can biosynthesize all of the 20 standard amino acids, while animals (including humans) must obtain some of the amino acids from the diet and the digestive process. Some ingested amino acids are used for protein biosynthesis, while others are converted to glucose, which is very important under starvation conditions as it allows the body’s own proteins to be used to support life.
A complete protein contains the 20 essential amino acids in the correct proportions. The number of essentials required in the daily diet differs between children and adults. In adults, the nine essential amino acids are isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, histidine, and valine. Infants require the amino acid argine, and all the remaining non-essential amino acids necessary are recycled by the body from other amino acids.
It is more challenging when eating a vegetarian diet to get all the amino acids, the body requires to satisfy the daily intake of complete proteins, but with the correct combination of foods, it can be achieved. Most beans (besides soybeans) are low in methionine. Nuts and grains are low in lysine, but a combination of nuts and grains will result in a complete protein. The grain quinoa and soy are the exceptions to this rule as they both contain complete amino acid profiles.
We have many alternative sources of proteins available, including dairy products, legumes, nuts, grains, vegetables, and readily available alternative protein products produced from soy and wheat gluten, including:
Tofu is soybean curd made from coagulated soymilk. The beans are soaked, crushed, and heated to produce soymilk to which a coagulating agent is added. The resulting soy curd is then pressed into tofu bars and is available with textures of soft to firm. Tofu is known for its high protein content and contains calcium, iron, and vitamins B1, B2, and B3.
Textured Soy Protein is defatted soy flour, which has been processed and dried with a sponge-like texture, which sometimes resembles meat and can be purchased with or without flavoring in most health food stores. Soy protein is also available incorporated into various vegetarian burgers and sausages, and as well as a good source of fiber and high-quality protein and is fortified with vitamin B12.
Soy Milk is an alternative to dairy and is widely available. Soymilk is made by soaking soybeans in water, which are then strained to remove the fiber. Compared to cow’s milk, soymilk is lower in carbohydrate, and fat content has not cholesterol, is a good source of protein, and is fortified with calcium, vitamin D2, B13, and B3.
Tempeh originated in Indonesia and is made by a natural fermentation process that gives it high content of protein, dietary fiber, and vitamins. Tempeh begins with whole soybeans, which are softened by soaking, de-hulling, and then partially cooking them; a mild acidulate is added to lower the ph, which starts the growth of the tempeh mold. The fermentation starter contains the spores of the fungus “Rhizopus Oligosporus” is mixed in, and the beans are spread into a thin layer and are allowed to ferment. The soy protein is more digestible because of this process that other soy products.
Seitan is made by rinsing wheat flour with water until the starch dissolves, leaving the gluten behind. The resultant gluten is a spongy mass with a similar texture to meat and can be used as a non-soy based meat alternative. Seitan is very versatile and can fried, steamed, baked, or eaten raw and can be found in most health food stores, flavored and unflavored. It is high in protein and iron, low in cholesterol and fat, and is naturally low in sodium.
So, how much protein does the human body require? During World War II, the United States government commissioned a study by the U.S. National Academy of Sciences to investigate issues of nutrition that might affect our national defense, and they established the “Recommended Daily Allowances” also known as RDAs.
In the early 1950s, the United States Food and Nutrition Board made a new set of guidelines, which includes the number of servings of each food group to make it easier for people to receive their RDAs of each nutrient. These standards have been presently accepted in 40 nations around the world and regulated by the Food and Drug Administration (FDA)
The charts below are the Recommended Dietary Allowances (RDA) established for humans. The amount of selected nutrients considered adequate to meet the known nutrient needs of the human body and is based on specific scientific date from the Food and Nutrition Board of the National Academy of Sciences and its standards are accepted in 40 nations.