Vegan Protein: Reduces the risk of certain disease

Proteins are the major structural component of muscle and other body tissues, and are used to produce hormones, enzymes and haemoglobin. An adequate dietary intake of protein is essential for growth and repair of body cells, the normal functioning and maintaining muscles and bones, transmission of nerve impulses and immunity.

Protein can also be used as energy, but is not the body’s preferred energy source, so this occurs only when the amounts of carbohydrate and fats consumed are insufficient.

 

Plant proteins in the human diet include a diverse range, which vary in terms of amino acid composition and digestibility. They are perfectly capable of satisfying human needs for all ages when consumed in appropriate mixtures.

The protein quality of a given food can be determined by the Protein Digestibility-Corrected Amino Acid Score (PDCAAS), which evaluates protein quality based on both the amino acid requirements of humans and their ability to digest the food. Most animal proteins (including meat, eggs and milk) have a PDCAAS score close to or equal to 1.0 (the maximum score), as does soy protein, but the scores for other plant proteins are generally lower.

Amino acids are classified as being either essential, meaning the body cannot adequately synthesize them and must obtain them from the diet, or non-essential, indicating that the body can make them. Protein foods that have large amounts of all essential amino acids are often referred to as high-quality proteins. These include foods of animal origin as well as a few plant foods including soy and the grains quinoa and amaranth. Other plant protein sources usually have all of the essential amino acids, but the amounts of one or two of these amino acids may be low. For example, cereals, and especially wheat, are particularly limited in their lysine content, and legumes are low in methionine. However, a combination of vegetable proteins with adequate energy intake provides enough amino acids of good quality to meet physiological needs. As most plant foods contain limited amounts of one or more essential amino acids, it was once thought that certain combinations of plant foods had to be eaten at the same meal to ensure a sufficient intake of essential amino acids. While nutritional adequacy can be maintained by including a variety of plant foods which “complement” each other in terms of their amino acid profiles (eg, consuming a mixture of grains and legumes or nuts). It was once thought that plant proteins needed to be combined within a meal by mixing grains and legumes to create a “complete” protein, also called complementary proteins, with good amounts of all essential amino acids.

Health professionals should encourage vegetarians to include a variety of protein-rich foods each day, not only to ensure an adequate intake of protein, but also to provide sufficient iron, zinc, calcium and vitamin B12.

 

Vegans can obtain protein in a variety of plant foods. This range of foods should include:

v  Legumes such as soybeans, chickpeas, lentils, kidney beans, split pea, and baked beans;

v  Whole grains such as brown rice, oats, buckwheat, polenta, quinoa and amaranth;

v  Soy products such as soy beverages, soy yoghurt, and tofu;

v  Nuts and seeds such as chia seeds, pumpkin seeds, flaxseeds, hemp seeds, hazelnuts, almonds;

v  Vegetables such as spinach, broccoli, asparagus, cauliflower, mushrooms and peas.

 While the lower protein intake and quality of protein in a vegetarian diet is often believed to be a concern, there is increasing evidence that consuming protein from plant rather than animal sources may, in fact, be one of the reasons why vegetarians generally have a lower risk of overweight, obesity and chronic disease. In comparison to protein foods of animal origin, most plant protein sources are naturally packed with other beneficial nutrients like fiber, vitamins, minerals, healthy fat, phytochemicals and antioxidants, and contain very little saturated fat, sodium, cholesterol and haem iron, all of which may contribute to a reduced disease risk in vegetarian and vegan diets. 

Plant proteins are certainly an opportunity to meet the future worldwide global protein needs, using complementarily.