About Phenylalanine & Weight Loss

You might have seen the term "phenylalanine" on the side of a diet cola can or even listed as an ingredient in children's vitamins. But maybe you did not know that it is an essential amino acid, one that the body needs but must get from food. Avocados and eggs have it, and so does the artificial sweetener aspartame. Phenylalanine can also assist with weight loss. Yet some people are not supposed to take it due to certain psychological and medical conditions.

Chemistry

• The University of Maryland's medical center states that phenylalanine comes in three forms: L, D and DL. L-phenylalanine comes from consumed food broken down into various proteins inside the human body, whereas D-phenylalanine does not naturally occur in foods but must be made in a lab. DL-phenylalanine is a combination of both the D and L forms. All forms of phenylalanine are used to make substances like dopamine (a chemical in the brain) and thyroid hormones. Without this amino acid, you might feel depressed, have low energy, experience memory issues and overeat because you do not ever feel full.

Phenylalanine and weight loss

• Because phenylalanine is an appetite suppressant and a stimulant, it helps to control overeating. It also provides a feeling of fullness; so eating foods that contain phenylalanine (milk, eggs and bananas) will reduce hunger. Essentially, phenylalanine consumption triggers the release of cholecystokinin in the intestines, which tells the brain to feel full even if only a small amount of food was consumed. For many dieters, controlling appetite is the key to successful weight loss. L-phenylalanine and DL-phenylalanine supplements can also be used to control appetite by stimulating the same process.

Phenylalanine supplementation

• To get enough phenylalanine through food, you might consume too many calories. If you decide to take supplements instead, consult a doctor first to ensure that you take the correct amount. SmartPublications.com suggests taking a phenylalanine supplement before meals to curb your appetite and make smaller portions satisfying. Also, L-phenylalanine and DL-phenylalanine supplements are used to remedy depression, reduce Parkinson's disease symptoms and help with vitiligo (skin condition).

Recommended daily allowance

• The recommended daily allowance (RDA) of phenylalanine is 15 mg per pound for an average adult. So a 150-lb. person would require 2,250 mg daily. The phenylalanine RDA also includes tyrosine (another amino acid); the body converts phenylalanine to tyrosine. You probably get enough phenylalanine from your regular diet to avoid deficiency, but to save calories and increase the appetite-controlling effect, you can supplement.

Contraindications

• It is possible to be deficient in phenylalanine if you have phenylketonuria (PKU), which is a rare disorder usually diagnosed in infancy. Those with PKU must limit intake of phenylalanine and should not supplement because they cannot process the amino acid. Pregnant women, people with elevated blood pressure and anxiety-attack sufferers should not supplement with phenylalanine. If you are taking a certain antidepressant (MAOIs), phenylalanine can increase blood pressure and should be avoided.