There is a lot of disagreement and controversy on the subject of protein requirements, particularly regarding how much protein an individual needs and what forms of protein are most beneficial.
Amino acids combine in long chains to form protein. The proper ratio of essential amino acids (amino acids that the body cannot produce for itself in adequate quantities) is necessary for building protein. Animal protein contains all of the essential amino acids, but not in the same ratio as human protein. Fruits and vegetables contain amino acids in ratios that vary greatly and often lack some of the essential amino acids. For this reason, experts tend to dismiss plant foods as poor protein sources.
In her book, Green for Life, Victoria Boutenko makes the case that leafy greens stand apart from other vegetables as an ideal source of all essential amino acids. She advocates eating a variety of greens in the form of green smoothies as an easy way to consume adequate amounts of leafy green vegetables and acquire the necessary combination of amino acids.
In addition to their role in building protein, individual amino acids all perform unique and important functions. Deficiencies in one or more specific amino acids can lead to psychological conditions such as depression and attention deficit disorder, as well as cravings for sweets, chocolate, tobacco, alcohol, and drugs.
Symptoms of protein deficiency include hair loss, weak nails, depression, fatigue, muscle weakness, frequent illness, slow wound healing, and weight loss. Cooking alters protein and destroys certain amino acids entirely, thereby creating a greater risk of deficiencies in protein or specific amino acids.
Long-term, excessive protein intake can cause kidney problems or accelerated bone loss, which may lead to osteoporosis. These symptoms are typically the result of protein supplements, rather than natural food sources.
|US Recommended Daily Allowance:||50 g|
Health Benefits of Protein/Amino Acids
|Concentration/Learning||Deficiencies in the amino acids tyrosine and phenylalanine have been linked to lack of focus and concentration, and attention deficit disorder (ADD).|
|Memory||Deficiencies in amino acids can lead to poor memory.|
|Mood||Deficiencies in certain amino acids can cause depression, attention deficit disorder, and other mental imbalances.|
|Muscles||Proteins, made up of amino acids, build and repair muscle.|
|Nails||A deficiency can lead to brittle, concave, or ridged nails. Can also cause white bands across nails.|
|Sleep Cycle||The amino acid tryptophan is converted into serotonin, the hormone that controls sleep.|
Food Sources of Protein/Amino Acids
|Buckwheat||11 g||22%||Contains abundant levels of all essential amino acids and has a protein quality score of 99.|
|Amaranth||9.4 g||19%||An excellent source of all essential amino acids.|
|Quinoa||8.1 g||16%||Provides all essential amino acids and is particularly abundant in lysine, which aids in tissue growth and repair.|
|Pumpkin Seeds||6.9 g||14%||One of the best sources of the amino acid tryptophan.|
|Wild Rice||6.5 g||13%||Provides all essential amino acids but is slightly low in lysine.|
|Sunflower Seeds||5.8 g||12%|
|Lambsquarters||4.2 g||8%||A good source of all 9 essential amino acids in the proper ratios.|
|Brazil Nuts||4 g||8%|
|Goji Berries/Wolfberries||4 g||8%||Contain 19 amino acids, including the essential amino acids.|
|Sweet Potatoes||4 g||8%||A source of all essential amino acids.|
|Durian||3.6 g||7%||Contains higher levels of protein than most other fruits.|
|Kale||3.3 g||7%||A good source of all 9 essential amino acids in the proper ratios.|
|Spinach||2.9 g||6%||Provides all essential amino acids in the necessary ratios.|
|Endive||1.3 g||3%||A good source of the amino acids tyrosine and phenylalanine|
|Hemp||N/A||N/A||A good source of protein when eaten as a seed or in protein powder form. Unlike other protein sources, people have not been found to be allergic to hemp protein. Hemp contains no trypsin inhibitors, which sometimes interfere with protein digestion of other seeds.|
|Leafy Greens - General||N/A||N/A||Provide all essential amino acids, particularly when a variety of greens are eaten. Best when eaten raw and well blended in a green smoothie.|
|Sprouted grains||N/A||N/A||All grains, when sprouted, are a good source of protein.|