Supplemental amino acids are generally regarded as safe, but watch out for potential side effects from arginine and methionine. Also be aware that branched-chain amino acids could upset the balance of neurotransmitters. Don't forget that a safe maximum dose has not been established for amino acids, so talk to your health care provider if you have any questions about the amount that works for your circumstances.
Balanced Amino Acids
Your body needs a sufficient amount of all the essential amino acids, but quantity isn't the only important factor. You also need a balanced proportion of each amino acid to ensure your body can produce proteins and keep your metabolism running. Laboratory animals experienced side effects when they consumed amino acids in proportions different from those they would have obtained through a balanced diet, according to a review in the Journal of Nutrition in June 2004. Research doesn't show serious side effects resulting from amino acid supplements, but they may interact with prescription medications, according to Drugs.com.
Arginine Side Effects
Arginine helps remove toxic ammonia from your body and boosts your immune system, but it may be best known for its ability to stimulate the production of growth hormone and nitric oxide. Nitric oxide fills many vital roles, from lowering blood pressure to serving as a neurotransmitter in your brain. However, some people experience bloating, abdominal pain, diarrhea and gout from arginine supplements. It may seriously alter blood levels of potassium in people with liver or kidney disease. It also lowers blood pressure, which could be dangerous if you already have low blood pressure, reports MedlinePlus. Consult your physician before taking arginine if you've experienced a recent heart attack or you have diabetes, ulcers, allergies, asthma or herpes.
Methionine and Blood Vessels
In addition to building proteins, methionine is used to produce another amino acid, homocysteine. Taking methionine supplements may boost levels of homocysteine, which could be a health concern because high homocysteine can cause vascular disease. If you take take methionine supplements, be sure to get plenty of folate, vitamin B-6 and vitamin B-12, which are vital for reducing the amount of homocysteine in your bloodstream. Pregnant women are advised not to take methionine supplements, and no one should take high doses for a long time unless under the supervision of a physician, recommends Eskenazi Health.
Branched-Chain Amino Acids
The branched-chain amino acids -- leucine, isoleucine and valine -- promote muscle protein synthesis when they're taken before and after exercise, according to a report in the Journal of Sports Medicine and Physical Fitness in September 2008. Branched-chain amino acids, or BCAAs, also compete with other amino acids, such as tryptophan and tyrosine, for access to your brain. Since these amino acids use the same transporters to get inside your brain, the amino acid found in the largest concentration in your blood has a better chance of getting through than the others. Disproportionately high levels of BCAAs from supplements may reduce the amount of tryptophan and tyrosine transported into your brain, which results in lower levels of the neurotransmitters they produce, including mood-boosting serotonin.
- Bellevue College: Protein
- Drugs.com: Amino Acid-Based Nutritional Supplement
- Journal of Nutrition: The Nature of Human Hazards Associated With Excessive Intake of Amino Acids
- Journal of Sports Medicine and Physical Fitness: Branched-Chain Amino Acid Supplementation Does Not Enhance Athletic Performance But Affects Muscle Recovery and the Immune System
- DermnetNZ.org: Nitric Oxide
- NYU Langone Medical Center: Arginine
- MedlinePlus: L-Arginine
- Proceedings of the National Academy of Sciences: The Atherogenic Effect of Excess Methionine Intake
- Eskenazi Health: Methionine
- Institute of Medicine: Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids