What You Need To Know
“L-” vs. “D-” Forms
This first part is a biochemical explanation for those of you who are interested. However, if you prefer the quick and easy explanation, simply skip over this part and go straight to ‘What You Really Need to Know’.
Supplemental amino acids basically come in two forms, either designated with an “L-“ or “D-“ prefix. Some distinguish the two different forms as follows: If the prefix is with an “L-“, then the amino acid is of a naturally occurring form as with foods and if the prefix is with a “D-“, then the amino acid is synthetic. This is not an accurate definition as both forms are naturally occurring in nature.
The “L-” and “D-” prefix actually refers to the chemical structure of the amino acid; “L-” refers to a direction the amino acid rotates the plane of polarized light. In simpler terms, it means if the light rotates clockwise, the isomer (in this case the amino acid) is labeled as “D-“; likewise if it rotates to the right, the amino is labeled as “L-“. It is important to note that the rotation is based on the observation towards the traveling light.
So basically, if a “D-“ and an “L-“ isomer, amino acid, are side by side, they would, in essence, be a mirror-image of each other; like our hands…one left and one right.
Naturally occurring amino acids of the “L-“ form is also known as left-handed proteins whereas naturally occurring “D-“ form amino acids are known as right-handed proteins. They have the exact same structure but are simply the mirror-image of each other.
What You Really Need to Know
Amino acids with the “L-“ form are absorbed in the body immediately and directly whereas the “D-“ form must first be converted by the body into a usable form before it can be absorbed.
In the U.S., the FDA prohibits the sale of the “D-“except in the cases of phenylalanine and methionine. In these cases, you can find both “L-“and “DL-“forms. DL-phenylalanine (DLPA) appears to be more effective in depression than simply the “L-“form of phenylalanine.
“Free form” vs. Peptide Bonded
- Free form amino acids are singular molecules, not attached by peptide bonds to other amino acids; thus, free form can be either “L-“ or “D-“ form aminos.
- Peptides are nothing more than amino acids linked (bonded) together forming a chain. When the peptide chain gets longer and longer, it becomes a protein.
Long chain peptides and whole proteins often require anywhere from 4 – 6 hours in order to digest. If some remain undigested due to malabsorption can cause gastrointestinal discomfort and allergic-type reactions.
The benefit of free form amino acids (as well as di- and tripeptides; 2 and 3 amino acids bonded together) is that they do not need to be digested; they are assimilated directly into the body and are readily utilized.
Ideally, you should look for crystalline, free-form, amino acids. Many people are under the wrong assumption when they buy soy proteins that it is free form, when in actually soy proteins (as well as milk proteins) only contain small amounts of free form amino acids and mostly are comprised of whole proteins and peptide. These proteins must first be broken down into single amino acids by your digestive system in order for your body to be able to use the protein.
It is important to note, that although it is possible to get all the protein you need from your diet, the problem arises with poor digestion, high stress, pollution, excess alcohol consumption, and processed foods which is a growing societal concern.
Remember a chain reaction of a deficiency can start from any link in the chain. Amino acids need vitamins and mineral and vitamins and minerals need each other as well as amino acids.
We live in a less than perfect society with increasing health care issues. The logical approach to these issues would be to get to the root cause rather than mask the issue with more chemicals; pharmaceutical drugs as the first choice.
The long term results of this “address the symptom only” medical approach will be revealed in years to come.
Special Note Regarding Digestive Side Effects
Free form amino acids are absorbed immediately and; thus, do not consist of fiber (bulk) as with a food substance. For this reason, some people may experience constipation.
If these occur, or for the prevention of this occurring, make sure you are taking in plenty of fiber and drinking plenty of water.
Rule of thumb: When you increase protein, also increase water.
On rare occasions, diarrhea may also occur; however, usually in cases of extreme therapeutic dosages (15 grams or more per day). It is always best to start with smaller amounts and slowly increase if needed.