Acetyl-L-carnitine is an amino acid that occurs naturally. In animal studies, it’s been found to increase the energy production in nerve cells, protect the nerve cells from toxins, maintain the number of receptors on nerve cells, and increase the availability of acetylcholine. Over the last 30 years, there have been many studies on the effects of acetyl-L-carnitine on memory in dementia patients.
The results have been mixed. In a meta-analysis of 21 double-blind, placebo-controlled studies, 499 of mild cognitive impairment or Alzheimer’s patients were given 1.5 to 3.0 grams of acetyl-L-carnitine a day versus placebo for three to 12 months. The results showed that acetyl-L- carnitine improved cognitive functions in patients with mild cognitive impairment, and prevented cognitive deterioration. This effect was first noted at month three of treatment.
A typical dose of acetyl-L-carnitine is 1,000 to 3,000 milligrams (mg) a day. The most common adverse effects include stomachache, nausea and diarrhea. Though the meta-analysis showed beneficial effects, there is an equal number of studies failing to show any benefit. Earlier positive studies used only a small number of Alzheimer’s patients treated for a short period of time. As well, study design was fair to poor. Still, most studies clearly show that adults under 65 with mild dementia were the ones who benefited from acetyl-L-carnitine treatment. We need better studies before I could fully recommend the use of acetyl-L- carnitine in dementia.
In animal studies, ginkgo biloba increases blood flow to the brain. It has antioxidant properties to protect the brain cells from oxidative stress. The effects of ginkgo on cognitive functions in Alzheimer’s have been studied extensively. The results are mixed. In a meta-analysis of nine studies involving 2,372 patients with Alzheimer’s or dementia assigned to receive the ginkgo or placebo for 12 to 52 weeks, those treated with the herb showed a significant improvement in their cognitive functions as compared to those on placebo. This herb was well tolerated.
A typical dose of ginkgo biloba is 120 mg to 240 mg a day. Use caution when ginkgo is combined with vitamin E, especially if you are taking anticoagulants such as warfarin.
Many studies, though, fail to show a beneficial effect of ginkgo for dementia. There are several explanations. The effectiveness of gingko may depend on the sensitivity of the population studied. Or, it may depend on the severity of the dementia (mild to severe), or on the sensitivity of the instrument used to measure cognitive changes. It also could be due to dosage used.
While both herbs are promising, know that the evidence is very much mixed. Always talk to your doctor or pharmacist before adding a new supplement to your routine.
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