The clinical benefits of Acetyl-L-Carnitine

Townsend Letter for Doctors and Patients,  August-Sept, 2002  by Robert Crayhon

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Nutrition can play an important role in promoting brain wellness. The older we are, the more likely we are to suffer from cognitive loss. While some survive into their sixth and seventh decades with good mental function, this becomes less likely as we age further. Decline is almost universal in at least one cognitive area among those over 85. (1) Are there nutrient strategies that can slow or even prevent this decline?

Certain nutrients have also undergone examination for their role in promoting brain health in older adults. One of the most extensively researched nutrients for its role in promoting brain wellness is Acetyl-L-Carnitine (ALCAR). ALCAR has demonstrated marked positive effects on brain aging, both from a preventive and therapeutic standpoint.

ALCAR is the O-acetylated form of the fatty acyl ester L-carnitine. ALCAR benefits mitochondrial efficiency and functions as an antioxidant within the mitochondria, helping neurons maintain maximal energy levels. ALCAR increases acetylcholine levels in the brain, one of the main neurotransmitters needed for learning and memory. Acetylcholine is the main neurotransmitter deficiency that occurs with age. There is also a great deal of evidence that age-related memory loss is cholinergic in nature. Therefore, maintaining healthy acetylcholine levels must be the centerpiece of any brain antiaging strategy. ALCAR levels decline markedly as we age, even in healthy adults. (2) Restoring ALCAR levels to those seen in twenty-year olds may be desirable for older adults. Declining ALCAR levels may in fact be one of the causes of the cognitive decline seen with aging.

Optimizing Neuronal Energy

For brain longevity, it is essential that neurons maintain a constant supply of energy to protect against cell loss. ALCAR maximizes neuronal energy production, (3,4) and regenerates mitochondrial function, especially cellular respiration, mitochondrial membrane potential, and cardiolipin levels. (5)

Brain Protector

ALCAR significantly reduces the amounts of damaged fats such as lipofuscin as the brain ages, a sign that ALCAR is slowing brain aging. (6) Double-blinded studies in humans show that ALCAR also protects against such ischemia-induced free radical damage to neurons. (7,8) Brain levels of ALCAR often determine how many cells survive an ischemic event. (9) ALCAR also acts as an antioxidant through its ability to naturally raise production as well as release of the free radical scavenger melatonin. (10,11)

Antioxidant levels in the substantia nigra decline with age, (12) increasing risk of damage to the dopanergic neurons in this region of the brain. ALCAR increases levels of glutathione in the neurons of the substantia nigra, which suggests that ALCAR may help protect and be useful in the prevention and perhaps the treatment of Parkinson's disease. (13) ALCAR has been found to protect against MPTP induced Parkinsonism in primates (14) and may protect against Parkinson's in humans. (15)

Increasing Molecules Needed for Memory

ALCAR increases levels of nerve growth factor (NGF)--an important brain healing compound. In the central nervous system, nerve growth factor (NGF) protects cholinergic neurons. NGF helps increase levels of choline acetyltransferase (ChAT), which makes the valuable neurotransmitter acetylcholine. The aging process reduces both nerve growth factor levels and the ability of neurons to bind to this valuable cellular messenger. ALCAR ameliorates these age-related deficits, therefore demonstrating another way it naturally helps create more acetylcholine needed for neuronal transmission, learning, and recall. (16) ALCAR has been found to optimize the response of the NMDA receptors and lessen their decline in number. (17,18)

Treating Depression

Research has shown that ALCAR is one of the most valuable compounds for relieving depression, (19,20) especially in older adults. (21) The usual dose used is 3 g/day. (22)

Reversing Senility

There are over 30 studies which show that ALCAR slows or prevents age related decline in mental function. (23) 1.5 g/day of ALCAR given to 236 older adults for 45 days significantly increased the effectiveness of performance on all the measures of cognitive functioning, memory performance, and constructional thinking. (24) Twenty adults given 1.5 g of ALCAR per day showed that it reversed many of the signs of aging. Cognitive ability, depression, behavioral and self-sufficiency performances and quality of life all improved. (21) Studies of 40 senile patients given 1.5 g/day of ALCAR for 40 days (25) and of 481 subjects given 2 g for 150 days showed similar results. (26) Two g/day of ALCAR enhances learning in older adults. (27,28) ALCAR also improves directional and word memory after only a few weeks of treatment. (29)

Speeding Stroke Recovery

One-hundred sixty patients who had had a stroke a year or more ago were given 1.5 g ALCAR each day orally for eight weeks. This caused a marked degree of functional recovery, as well as improved mood and attention conditions. (30) Twenty patients with chronic cerebrovascular disease who suffered an ischemic stroke at least 6 months before were given a single 1.5 g dose of ALCAR intravenously, leading to acutely enhanced cerebral blood flow. (31)