The Tyrosine Factor

Words: Dr Richard FIRSHEIN

The evidence of stress-induced chemical cascades that Dr Hans Selye, PhD, known as the founding father of stress studies, proposed in 1936, hold up even today. He suggested that when we’re stressed, neurotransmitters caused a part of the brain known as the hypothalamus to produce a substance called corticotropin-releasing factor [CRF]. This stress substance travels to our hormone factory, the pituitary gland, and signals the release of adrenocorticotropic hormone, another chemical that warns our bodies about life’s pressures. Finally, this hormone cues the adrenal glands to secrete cortisol and adrenaline. The result? Increased blood sugar, faster heart rate, and higher blood pressure.

Many people, young and old, reach a saturation point, where they can no longer tolerate stress and its effects on the body. Eventually, norepinephrine becomes depleted, and the immune system is suppressed. A study in The New England Journal of Medicine found that psychological stress increases the risk of acute infectious respiratory illness. There is even evidence that stress hurts us at the most basic cellular level. Each of our cells contains a powerhouse called the mitochondrion, which regulates energy production all through the body. In rats, acute stress was found to cause severe mitochondrial damage, illustrating the far-reaching powers of sustained pressure. Even the stress of exercise can have an impact on health, depending on your genetic legacy. A study in a neurology journal showed that hard physical activity can lead to a decrease in the synthesis of norepinephrine.


Neurotransmitters like norepinephrine can become depleted if our stress levels are excessive. One extreme example of this is chronic fatigue syndrome [CFS]. An epidemic that has reached its highest levels within the last ten years, chronic fatigue syndrome has gone by many names, from chronic fatigue immune dysfunction syndrome [CFIDS] to ‘the yuppie flu.’ Part of the mystery of CFS stems from the fact that we still don’t know what virus causes the syndrome. Epstein-Barr virus, or HHV-6, another member of the herpes family, has been implicated. There is also some speculation that it is triggered by what are thought to be ‘stealth’ viruses, which may actually evade the immune system’s powerful surveillance.

Whatever the cause, one thing is certain: CFS is not just fatigue. While most of us have been exceedingly tired at some point in our lives, sleep eventually restores our energy and vitality. For sufferers of CFS, however, there is no such thing as a good night’s sleep. They are constantly plagued with a deep, unrelenting exhaustion that sleep cannot remedy. They have the will and the desire to live a normal life, but their fatigue wears them down.

This fatigue interferes with a normal life, normal relationships, and normal day-to-day functioning. CFS has been defined by the Centres for Disease Control as a set of major and minor criteria, one hallmark being a debilitating fatigue lasting at least six months that reduces average daily activity to below 50 per cent. One group of criteria for CFS suggests that hypotension, or abnormally low blood pressure, may also be associated [with CFS] in some people.

Many patients suffering from CFS report that stress exacerbates their condition. Clearly, stress is not just a mental dysfunction; it can dismantle the health of the whole body. Patients have come to me hopelessly lethargic, wanting to go out and conquer life, but constantly lacking the energy. Whether it be a high-pressure job in which they must consistently perform well, or even just getting the simplest tasks accomplished, stress is severely handicapping their abilities.

I have found that there is a nutrient so important to energy and stamina that the United States military was conducting studies on its benefits; this nutrient is tyrosine. In fact, tyrosine may be the natural antidote to today’s fast-paced lifestyle. Of all the supplements I study and prescribe in my practice, tyrosine is one of my absolute favourites. With its help, I’ve seen people emerge from the fog of depression, handle stress better, and generally improve their condition.

How Tyrosine Helps

Tyrosine is an amino acid — a building block for protein — that is found in every day dairy products, such as cheese and milk, and meats such as chicken and turkey. While all of the 20-odd amino acids that form our bodily proteins serve as building blocks for the brain, tyrosine plays an especially important role in keeping the nervous system alive and running. Just like two other amino acids, tryptophan and phenylalanine [which is found in the sugar substitute, aspartame], tyrosine is known as an ‘aromatic’ amino acid. It has a special ring structure, shaped like a hexagon. Unlike non-aromatic amino acids, any dietary tyrosine we consume is readily absorbed into our brains. This quality allows tyrosine the heady power to tinker with our moods, feelings, emotions, and cognitive abilities.

Tyrosine is the precursor of three of the most crucial neurotransmitters used as chemical messengers by the neuronal cells that wire our brains: dopamine, norepinephrine, and epinephrine [otherwise known as adrenaline]. The life-changing power of antidepressant drugs is often due to their ability to increase both dopamine and norepinephrine. Though the role of norepinephrine is subtle, it is absolutely necessary for preparing our bodies for the fight-or-flight reaction. It conserves energy and stimulates adrenaline release. A study in Military Medical Journal shows that intensely stressful situations, like fighting in a war, can deplete our stores of norepinephrine. Tyrosine not only restores low levels of norepinephrine but also improves performance and cognitive functioning during times of extreme pressure.

Studies of human subjects at high altitudes and freezing temperatures show that tyrosine supplements prevent the learning, motor, and memory difficulties that usually arise in stressful environments. Second, tyrosine is a source of energy. A study on lab animals showed that tyrosine renewed the enthusiasm and motivation normally eliminated by stressful surroundings. Similar research has shown that tyrosine can restore significant amounts of energy to sufferers of chronic fatigue syndrome and dysthymia — depression that is not as severe as full-blown, clinical depression — by acting as a natural stimulant. This brain-boosting nutrient can be useful as an analgesic and as a potential treatment for disorders like narcolepsy. It may even help ameliorate PMS too.

Dr RICHARD FIRSHEINDO, is the Founder-Director of The Firshein Center for Comprehensive Medicine in New York City. He is a leading innovator and authority in the field of preventative and nutritional medicine, integrating Western and Eastern medical practices. He is Board Certified in Family Medicine and has served as professor of family medicine. An internationally recognised leader in the field of integrative medicine and healthy aging, a cancer researcher, prolific author and writer, Dr Firshein has written several ground-breaking books, including the bestselling Reversing AsthmaYour Asthma-Free ChildThe Nutraceutical Revolution and The Vitamin Prescription [For Life]. This article is ©Dr Richard Firshein.

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