| TYROSINE Tyrosine is a nonessential amino acid, which means that it is manufactured from other amino acids in the liver; it does not have to be obtained directly through the diet. It is abundant in insulin as well as the enzyme papain and can be synthesized from the amino acid phenylalanine in the body. Tyrosine is important to overall metabolism. It is a precursor of adrenaline and the neurotransmitters norepinephrine and dopamine, which regulate mood and stimulate metabolism and the nervous system. Requires pyridoxal-5-phosphate (P5P) a form of vitamin B6 to be converted into norepinephrine. P5P deficiency will lower norepinephrine levels, even if Tyrosine levels are normal. Precursor to thyroxine and growth hormone. Main Functions: • Precursor to neurotransmitters dopamine, norepinephrine, epinephrine (adrenaline) and melanin. • Effective anti-depressant for norepinephrine-deficient depressions. Tyrosine is preferred over Phenylalanine, which is also a precursor to all of the above neurotransmitters. Phenylalanine is one step removed from the metabolic process, and can aggravate high blood pressure. • Acts as a mood elevator; a lack of adequate amounts of tyrosine leads to a deficiency of norepinephrine in the brain, which in turn can result in depression. • It also acts as a mild antioxidant, • Suppresses the appetite • Helps to reduce body fat. • It aids in the production of melanin (the pigment responsible for skin and hair color) and in the functions of the adrenal, thyroid, and pituitary glands. • Increases energy, improves mental clarity and concentration. • Tyrosine attaches to iodine atoms to form active thyroid hormones. Not surprisingly, therefore, low plasma levels of tyrosine have been associated with hypothyroidism. • Supplemental L-tyrosine has been used for stress reduction, and research suggests it may be helpful against chronic fatigue and narcolepsy. It has been used to help individuals suffering from anxiety, depression, low sex drive, allergies, and headaches, as well as persons under going withdrawal from drugs. It may also help people with Parkinson's disease. Tyrosine Deficiency: Symptoms of tyrosine deficiency can also include low blood pressure, low body temperature (such as cold hands and feet), and restless leg syndrome. Deficiencies seen in: • Depression • Chronic Fatigue Syndrome • Gulf War Syndrome • Hypothyroidism • Parkinson's Disease • Drug addiction and dependency Tyrosine Excess Seen In: • Hypertthyroidism • Chronic liver disease; cirrhosis Rich Food Sources of Tyrosine Natural food sources of tyrosine include almonds, avocados, bananas, dairy products, lima beans, pumpkin seeds, and sesame seeds. Caution and Side effects Persons taking monoamine oxidase (MAO) inhibitors, commonly prescribed for depression, must strictly limit their intake of foods containing tyrosine and should not take any supplements containing L-tyrosine, as it may lead to a sudden and dangerous rise in blood pressure. Anyone who takes prescription medication for depression should discuss necessary dietary restrictions with his or her physician. |