By Caroline Kanaiza
What is Serine?
Serine is one of the non-essential amino acids that make up protein. It is synthesized in the body. It exits in L-serine and D-serine forms.
Health Benefits of Serine
Serine, even though a non-essential amino acid, provides crucial health benefits. It plays roles in protein, fatty acid, genetic code carriers (DNA and RNA) synthesis, and muscle build-up. Serine is a constituent in the brain and protective covers of nerves. Therefore, serine is an important amino acid for the proper functioning of the brain and nervous system. Furthermore, serine boosts healthy immune system by aiding the production of antibodies.
Serine is also a component of all cell membranes.
Additional serine’s health benefits come indirectly through its effect on other biochemicals. For example, serine is a precursor for the production of amino acids such as glycine, cystein, and tryptophan. Tryptophan, necessary for the synthesis of serotonin and functioning of neurotransmitters, is known to help relieve stress, anxiety and depression.
Serine Deficiency
Serine deficiency symptoms include slow or delayed cognitive and physical skills (psychomotor retardation), seizures and microcephaly. Microcephaly refers to health condition in which the head size is smaller than normal and is caused by underdevelopment of the brain.
Food Sources High and Low in Serine
Among the high serine foods are dried forms of egg and soybean products. A select list of dietary sources of serine are provided in the table below. The food items on the top of the table contain the highest serine level among the common foods in the Northen Americas, catalogued in the US Nutrients database.
| Serine food source | Serine content g/100 gram of food portion |
|---|---|
| Egg, white, dried | 5.59 |
| Soy protein isolate | 4.59 |
| Egg, whole, dried | 3.77 |
| Seeds, sesame flour, low-fat | 2.73 |
| Egg, yolk, dried | 2.81 |
| Soybeans, mature seeds, raw | 2.36 |
| Tofu, dried-frozen (koyadofu) | 2.26 |
| Soy flour, full-fat, raw | 2.00 |
| Milk, buttermilk, dried | 1.87 |
| Nuts, butternuts, dried | 1.64 |
| Cheese, swiss | 1.64 |
| Chees, provolone | 1.64 |
| Egg, yolk, raw, fresh | 1.33 |
| Cheese, muenster | 1.30 |
| Lentils, raw | 1.29 |
| Peanuts, all types, raw | 1.27 |
| Cowpea, catjang, mature seeds, raw | 1.19 |
| Cheese, feta | 1.17 |
| Nuts, almonds | 1.01 |
| Egg, whole, raw, fresh | 0.97 |
| Chickpeas (garbanzo beans, bengal gram), mature seeds, raw | 0.97 |
| Seeds, sesame butter, tahini, from raw and stone ground kernels | 0.97 |
| Flax seed, raw | 0.97 |
| Nuts, walnuts, english | 0.93 |
| Salami, Italian, pork | 0.90 |
| Beef, round, top round, separable lean and fat, trimmed to 1/8" fat, select, raw | 0.87 |
| Beef, top sirloin, separable lean only, trimmed to 1/8" fat, choice, raw | 0.86 |
| Fish, salmon, pink, raw | 0.81 |
| Crustaceans, shrimp, mixed species, raw | 0.80 |
| Egg, white, raw, fresh | 0.80 |
| Chicken, broilers or fryers, thigh, meat only, raw | 0.68 |
| Chicken, broilers or fryers, wing, meat and skin, raw | 0.66 |
| Sausage, Italian, pork, raw | 0.55 |
| Milk, sheep, fluid | 0.49 |
| Pork, fresh, separable fat, raw | 0.26 |
| Hummus | 0.25 |
| Soy milk, fluid | 0.18 |
| Milk, goat, fluid | 0.18 |
| Milk, whole, 3.25% milkfat | 0.11 |
| Asparagus | 0.11 |
| Snap beans, green, raw | 0.10 |
| Milk, human, mature, fluid | 0.04 |
Serine data source: USDA National Nutrient Database for Standard Reference, Release 19 (2006).
References:
de Koning TJ, Klomp LW. 2004. Serine deficiency syndromes. Curr Opin Neurol. 2004 Apr;17(2):197-204.