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which foods are rich in L-serine?

For a full list of publications on L-serine from Brain Chemistry Labs, see this link.

Jump straight to the table of foods high in L-serine

Humans are composed of hundreds of thousands of proteins that make-up a wide variety of tissues. These proteins perform an equally daunting variety of tasks from forming skin, to making hair and fingernails or organs like the heart.

Each protein has a specific job, for example proteins called enzymes are tasked with detoxifying alcohol from our liver every time we have a have a drink, whilst proteins in our eyes enable us to see.

Our DNA provides the blueprint for making proteins, by specifying the unique sequence of amino acids – building blocks for proteins. Amino acids are like individual pearls in a necklace or the carriages on a train.

Humans use 20 different amino acids assembled into unique sequences, and this enables the generation of hundreds of thousands of novel proteins.

Amino acids are like individual pearls in a necklace or the carriages on a train

Of the 20 amino acids that we need to make proteins, some are termed “essential” and some “non-essential”. Whilst our bodies can synthesise some amino acids, (these are “non-essential”), others we need to get through our diets, hence “essential”.

What is L-serine?

Whilst L-serine is technically an “non-essential” amino acid, some scientists refer to it as “conditional” since it plays such an important role in our bodies.

L-serine is not only a component of proteins, but it also participates in neurotransmission, the process whereby our neurones communicate. In partnership with glutamate, serine can trigger the opening of specialised receptors on the surface of neurones, enabling them to send messages to adjacent cells.

L-serine also plays a critical role in controlling signalling processes in the body. Specialised molecules called phosphates can attach themselves to individual serine residues inside proteins and effectively turn signals inside cells on or off. Within the body, ninety-five percent of these processes are controlled by serine, making it a critical amino acid for humans.

L-serine is classified as a “conditional non-essential amino acid” meaning even though our bodies can synthesise it, we don’t always have enough.

Although L-serine is a non-essential amino acid, there are times when we don’t have access to enough. This is particularly detrimental during development, when a deficiency in L-serine can affect growth and development. Mutations in the molecules that make L-serine from glycine can cause seizures, retardation, reduced IQ, and microcephaly. If detected early enough, these effects can be partially and sometimes completely reversed with L-serine supplementation.

What’s the evidence that having more serine in my body is a good thing?

At the Brain Chemistry Labs, we are concerned with researching causes and cures for brain diseases such as Alzheimer’s disease and amyotrophic lateral sclerosis (ALS).

In our search for environmental factors that are implicated in neurodegenerative disease, we initially looked to places where higher than normal levels of these diseases exist. One of these places, also referred to as a “hot spot” or “cluster” includes Guam, where the incidence of ALS was 100-fold greater than the general community.

However, it also occurred to us –– why not look in areas where there is less disease to see if we could figure out what made these people more resilient than the general population?

And that’s how scientists ended up in the tiny village of Ogimi, on the island of Okinawa, off the East coast of Japan. Located in a “blue zone”, this village is also known as longevity village for the many residents over the age of 90. The locals, who speak a dialect of Japanese, don’t even have a word for Alzheimer’s in their language.

Dr Paul Cox, a renowned ethnobotanist, was intrigued as to why this small population of people appeared to be protected from age-related diseases. Previous research had already showed their genes were not significantly different to the mainland Japanese who were susceptible to ageing and neurodegeneration, so he decided to look at their diet.

He immediately noticed one striking difference –– whilst mainland Japan got most of their calories from rice, the main staple of the Okinawanas diet was tofu. After careful documentation and collection of foodstuffs from their daily intake, Dr cox returned to the lab to analyse the amino acid content of the food.

What he found was super high levels of L-serine –– around 3 times the daily intake of a north American. Thus, a lifetime of high L-serine ingestion correlated with longevity and a lack of neurodegenerative diseases.

However, as any good student of science knows, correlation does not equal causation.

But there was more evidence for L-serine having neuroprotective role to come.

Studies (see here and here) using human cells in culture have shown L-serine increases the levels of protective genes and proteins, thereby upregulating the cell’s protective capabilities. We and others have also shown that L-serine blocks the action of a specific toxin found in cyanobacteria (more commonly known as blue green algae) that has been linked to triggering ALS and Alzheimer’s disease.

Importantly, clinical trials in humans have shown L-serine to be safe, relatively free from side-effects and effective at slowing the progression of ALS in patients. The FDA classifies L-serine as “GRAS” – Generally Regarded As Safe – since it is a dietary amino acid.

How can I increase the level of L-serine in my diet?

Not all the foods that the Okinawans eat are accessible outside of the village, but just about any food that is high in protein will also contain L-serine (since it is a component of proteins). Note: the best bang for your buck, gram for gram, are egg whites and soy protein.

See our abbreviated list below.

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Source: United States Department of Agriculture Agricultural Research Service USDA Food Composition Databases    https://ndb.nal.usda.gov/ndb/search/list?home=true   . NDB_No = Nutrient Database Number.    This is by no means an exhaustive list, see the URL for more detail. Notes: I have not included molluscs nor spirulina in this list, even though both these foodstuffs contain high levels of L-serine, since they have both been found to contain the cyanoneurotoxin, BMAA.

Source: United States Department of Agriculture Agricultural Research Service USDA Food Composition Databases https://ndb.nal.usda.gov/ndb/search/list?home=true. NDB_No = Nutrient Database Number.

This is by no means an exhaustive list, see the URL for more detail. Notes: I have not included molluscs nor spirulina in this list, even though both these foodstuffs contain high levels of L-serine, since they have both been found to contain the cyanoneurotoxin, BMAA.