Proteins in the 21st Century

Protein intake is an essential consideration in our daily diets, particularly with the growing interest in 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 that 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 animals’ 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, and 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, and honey

- 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 primarily of whole grains and some fish

- Flexitarians are on transitional diets, moving from animal products to a vegetarian diet

- Pescetarianism diets include fish and shellfish

- Pollotarianism diets include poultry

The health benefits of Vegetarianism are numerous, including a lower incidence of heart disease, high blood pressure, type 2 diabetes, colon cancer, and obesity, which are attributed to lower saturated fats and cholesterol, as well as 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. They are essential parts of all organisms. Proteins participate in virtually every process within our cells, are vital to our metabolism, and have structural and mechanical functions that maintain cell shape, regulate cell signaling, facilitate immune responses, and support cell duplication.

The amount of protein required for normal health varies depending on factors such as body weight, age, physical activity, health condition, and environmental factors. Generally, protein intake should equal protein loss, which occurs through urine, feces, blood, sweat, skin, nails, and hair. When protein intake is less than protein loss, it is referred to as a negative protein balance, whereas when it is the reverse, it is referred to as a positive protein balance. Ideally, for healthy adults, a neutral protein balance should be attained. Growing children and pregnant or lactating women require more protein and should be in a positive protein balance. Other conditions that require a positive balance include individuals recovering from illness, those with increased insulin secretion, growth hormone, or testosterone levels.

Most microorganisms and plants can biosynthesize all 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. In contrast, others are converted to glucose, which is crucial under starvation conditions, as it enables the body’s proteins to be utilized to support life.

A complete protein contains 20 essential amino acids in the correct proportions. The number of essentials required in the daily diet differs between children and adults. The nine essential amino acids in adults are isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, histidine, and valine. Infants require the amino acid arginine, and the body recycles all the remaining non-essential amino acids from other amino acids.

It is more challenging to obtain all the amino acids the body requires to meet the daily intake of complete proteins when following a vegetarian diet. Still, 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 produces a complete protein. The grains 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 pressed into tofu bars, available in a range of soft to firm textures. 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 processed and dried with a sponge-like texture. It sometimes resembles meat and can be purchased with or without flavoring in most health food stores. Soy protein is also available and incorporated into various vegetarian burgers and sausages. It is 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 is then strained to remove the fiber. Compared to cow’s milk, soymilk is lower in carbohydrates and fat content, has no 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 a high content of protein, dietary fiber, and vitamins. Tempeh begins with whole soybeans, which are softened by soaking, de-hulling, and then partially cooked. A mild acidulant is added to lower the pH, which initiates the growth of the tempeh mold. The fermentation starter, which 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 due to this process than in 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 be fried, steamed, baked, or eaten raw. It can be found in most health food stores, both 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 U.S. government commissioned a study by the U.S. National Academy of Sciences to investigate nutrition-related issues that might impact national defense, and it 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 included 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 is based on specific scientific data from the Food and Nutrition Board of the National Academy of Sciences, and its standards are accepted in 40 nations.