NUTRITION AND CLINICAL DEPRESSIONHEALTH SYSTEMS EDITIONdiet. Choline and tryptophan canbe found in many freshwater fish,and tyrosine can be found incheese. 5 Foods that should beavoided are alcohol and caffeine.Alcohol acts as a central nervoussystem depressant, which makesthe situation worse, and caffeineinterferes with sleep and promotesnervousness.Signs andSymptoms of DepressionMany people attribute the feelingsinduced by depression toother causes such as inability tohandle stress, social stigma, andalcoholism. However, depressionis not difficult to spot, and specificsigns and symptoms exhibitedby a person are helpful inidentifying its presence (seeTABLE 1). 6Brain Biochemical ImbalanceNeurotransmitters are the naturalbiochemicals that facilitate communicationbetween brain cells.These substances control ouremotions, memory, moods,behavior, sleep, and learning abilities.Neurotransmitters are manufacturedin the brain from theamino acid precursors we receivefrom food. Without adequateamino acid conversion, sufficientamounts of neurotransmitters arenot produced. 7 Alcohol destroysthese essential precursor aminoacids, which is probably whyalcoholics seem so emotionallydown and depressed.The two major neurotransmittersinvolved in preventingdepression are serotonin (fromthe amino acid L-tryptophan)and norepinephrine (from theamino acids L-phenylalanine andL-tyrosine). It is interesting thatthe depressive symptoms exhibitedindicate which amino acidsare lacking: If the symptoms aresleeplessness, anxiety, or irritability,then L-tryptophan is low; ifthe symptoms are lethargy,Table 1Signs of Depression• Indecisiveness• Continual fatigue and lethargy• Loss of appetite or binge eating• Withdrawal from daily activities• Inability to concentrate• Lack of motivation andunresponsiveness to people• Feeling helpless, immobilized• Sleeping too much; using sleepto escape reality• Insomnia, particularly earlymorninginsomnia• Lack of response to good news• Ongoing anxiety• An “I don’t care” attitude• Easily upset or angered• Listening to mood musicpersistently• Self-destructive behaviorSource: Reference 6.fatigue, sleeping too much, orfeelings of immobility, L-tyrosineor L-phenylalanine is lacking. 7Conversion of AminoAcids to NeurotransmittersThe amino acid tyrosine, foundin large amounts in cheese, hasan amazing effect on depression.Tyrosine is a nonessential aminoacid that is synthesized in thebody from phenylalanine. As abuilding block for several importantbrain chemicals, tyrosine isneeded to make epinephrine,norepinephrine, serotonin, anddopamine, all of which work toregulate mood. Tyrosine also aidsin the production of melanin(the pigment responsible for hairand skin color) and in the functionof organs responsible formaking and regulating hormones,including the adrenal,thyroid, and pituitary glands.Tyrosine is also involved in thesynthesis of enkephalins, substancesthat have pain-relievingeffects in the body. 8Low levels of tyrosine havebeen associated with low bloodpressure, low body temperature,and an underactive thyroid.Because tyrosine binds to freeradicals, it is considered a mildantioxidant. Thus, tyrosine maybe useful for individuals whohave been exposed to harmfulchemicals (such as from smoking)and radiation. The usualdose is 3 to 6 g per day, taken onan empty stomach. Vitamins B 6and C need to be taken to facilitatethe conversion of tyrosine tonorepinephrine. 8An alternative to tyrosine isthe amino acid L-phenylalanine,which can also be converted intonorepinephrine. L-phenylalanineis converted to a substance called2-phenylethylamine (2-PEA). Lowbrain levels of 2-PEA are alsoresponsible for some depression.2-PEA is converted to tyrosine,which then converts to norepinephrine.L-phenylalanine is abetter start than tyrosine, but if itcauses the brain to race due tothe formation of 2-PEA, thepatient should start with tyrosine.A disadvantage to taking L-phenylalanine is its slight potentialfor raising blood pressure.There is also some evidencethat excess L-phenylalanine cancause headaches, insomnia, andirritability. For these reasons, it isimportant to start with a lowdose. L-phenylalanine doses canrange from 500 mg to 1,500 mgdaily and should be taken on anempty stomach. 8The FDA prohibited the manufactureand sale of tryptophanin the United States in the fall of1980. Although the FDA continuesto enunciate its concernabout the use of L-tryptophan asa single product and related compoundssuch as L-5-hydroxytryptophan,the agency does not prohibitthe marketing of dietarysupplements that contain lowerHS-30U.S. <strong>Pharmacist</strong> • November 2009 • www.uspharmacist.com
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