Читать книгу American Diabetes Association Guide to Herbs and Nutritional Supplements - Laura Shane-McWhorter - Страница 8
ОглавлениеOTHER NAMES • Thioctic Acid •
Alpha-lipoic acid is a vitamin-like substance called an antioxidant—a substance that protects cells from the damaging effects of oxidative stress. Scientists theorize that oxidative stress can lead to diseases such as cancer, heart disease, and diabetes. Alpha-lipoic acid is produced in the liver. In addition, alpha-lipoic acid is found in foods like broccoli, spinach, potatoes, yeast, and animal liver. In the laboratory, scientists can synthesize alpha-lipoic acid, which can then be given as an injection or formulated into tablets or capsules.
USES
People with diabetes use alpha-lipoic acid to treat nerve damage to the hands and feet (called peripheral neuropathy). This painful nerve condition can cause various symptoms such as burning sensations in the feet and difficulty controlling movement. Oxidative stress is thought to play a role in the progression of diabetic nerve damage. As an anti-oxidant, alpha-lipoic acid may decrease oxidative stress and improve symptoms such as pain. However, there is no evidence that alpha-lipoic acid prevents diabetic nerve damage. In addition, studies have not shown that alpha-lipoic acid significantly decreases blood glucose levels.
Although alpha-lipoic acid has been used for several years in Germany, long-term trials in the United States are needed determine whether alpha-lipoic acid slows progression or only improves symptoms of nerve damage. Much is still unknown about its use.
Alpha-lipoic acid is also used to treat many other conditions such as Parkinson’s, Alzheimer’s, cataracts, and glaucoma.
DOSE
Typical doses Typical doses of alpha-lipoic acid are 600 to 1,200 milligrams (mg) daily.
STUDIES
Alpha-lipoic acid has been studied in a number of randomized, double-blind, placebo-controlled studies (the gold standard design of scientific studies). Overall, these studies have shown that alpha-lipoic acid decreases symptoms of painful diabetic nerve damage when compared to a placebo (dummy pill).
One series of studies is called the ALADIN (Alpha-Lipoic Acid in Diabetic Neuropathy) trials.
• In the first ALADIN study, 260 patients with type 2 diabetes and diabetic nerve damage were given an injection of alpha-lipoic acid in various doses (100, 600, or 1,200 mg) or a placebo once a day. The total symptoms of nerve damage decreased in those who were taking any dose of alpha- lipoic acid versus those who were taking a placebo. Burning, tingling, loss of sensation, and numbness decreased significantly in those patients on 600-or 1,200-mg versus a placebo. Pain scores decreased significantly only in the 600- mg group versus the placebo group. The neurodisability score, which measures vibration, pinprick, ankle reflexes, and temperature sensation in the big toe, decreased, but the decrease was significant only for the group taking 1,200-mg versus the placebo group. A1C, a measure of average blood glucose over 3 months, declined in all groups, but not significantly.
• In the second ALADIN study, 65 patients with type 1 or type 2 diabetes and nerve damage received an injection of alpha-lipoic acid or a placebo for 5 days. Then patients received a 600-or 1,200-mg tablet of alpha-lipoic acid or a placebo daily for 2 years. Researchers measured improvements in nerve damage in the patients. Patients taking either dose of alpha-lipoic acid had significant improvements versus the placebo group, although not for all types of nerve damage. The patients’ neurodisability scores did not decrease, but the sample of patients may have been too small to detect changes. A1C did not decrease significantly, although A1C decreased from 9 percent to 8 percent after years in the 1,200-mg group.
• The third ALADIN study examined 503 patients with type 2 diabetes. One group of patients received a 600-mg injection of alpha-lipoic acid for 3 weeks and then received either a 600-mg tablet of alpha-lipoic acid three times daily or a placebo for 6 months. The other group received a placebo “injection” for 3 weeks, followed by a placebo tablet for 6 months. Nerve damage impairment decreased after 19 days in both groups of patients who took alpha-lipoic acid versus the placebo. However, after 7 months, there was no significant difference in nerve damage scores between the groups.
• A separate study evaluated 120 patients who took alpha- lipoic acid 5 days a week for a total of 14 treatments. Symptoms declined significantly.
• A follow-up to this study evaluated three different doses of alpha-lipoic acid (600, 1,200, or 1,800 mg) versus a placebo for 5 weeks in 181 patients with diabetes. Total symptom scores declined significantly by 51 percent, 48 percent, and 52 percent, respectively, in the alpha-lipoic acid treatment groups versus 32 percent in the placebo group.
• Yet another study examined the results of a number of studies of alpha-lipoic acid in people with diabetic nerve disease. The study found that 53 percent of patients on alpha-lipoic acid versus 37 percent on a placebo had improved scores in their symptoms.
• The NATHAN I (Neurological Assessment of Thioctic Acid in Neuropathy) trial is an ongoing, long-term, multi-center trial in North America and Europe that is assessing the role of alpha-lipoic acid given orally for the prevention and treatment of diabetic neuropathy. A follow-up study called NATHAN II is currently investigating alpha-lipoic acid for relief of painful neuropathy symptoms, but as of this printing, the results have not yet been published.
SIDE EFFECTS AND DRUG INTERACTIONS
To date, no serious side effects from alpha-lipoic acid have been reported, even though it has been used intravenously and in long-term trials. However, you may experience allergic reactions if you take alpha-lipoic acid. Alpha-lipoic acid may cause nausea and vomiting, as well as vertigo.
Anecdotal information indicates that alpha-lipoic acid may affect the thyroid, so ask your doctor whether you should have your thyroid levels tested. Studies in animals have shown that high doses of alpha-lipoic acid can be harmful when a thiamine deficiency is present. Ask your doctor about this side effect, particularly if you regularly drink large quantities of alcohol and may thus be thiamine-deficient. Your doctor may recommend that you take thiamine supplements; but ask your doctor first. Some anecdotal reports indicate that alpha-lipoic acid or other antioxidants may decrease the beneficial effects of chemotherapy, so also discuss this side effect with your doctor.
Monitor your blood glucose closely when taking alpha- lipoic acid and diabetes medications such as sulfonylureas. Low blood glucose can occur. In addition, you should not take alpha-lipoic acid and antacids at the same time because your body may not absorb the alpha-lipoic acid properly. Instead, space these medications a few hours apart.
