polysaccharides and glycoprotein. They are thought to stimulate the body’s ability to transport excess glucose from the blood into cells and tissues where it is needed. Some scientists suspect that the high fiber content of the gel itself may promote the body to use glucose more effectively. Nonetheless, aloe’s effect on blood glucose has not been confirmed in large, rigorous, long-term studies.
Aloe latex is another form of aloe. It has a laxative effect and can be taken as a juice or dried and taken as a tablet. It is not used to treat diabetes.
DOSE
There is no recommended There is no recommended dose, since necessary dose-finding studies have not been conducted.
STUDIES
Three small studies have indicated that aloe may decrease blood glucose. It may also decrease triglycerides but not total cholesterol.
• A study of five patients with type 2 diabetes who took one- half teaspoon of aloe sap twice daily found that average blood glucose decreased. But the study was very small and did not include control subjects (i.e., patients who did not take aloe).
• A small study of 40 patients with type 2 diabetes who took one tablespoon of aloe gel or a placebo (“dummy gel”) twice a day for 6 weeks found that fasting blood glucose decreased significantly in the aloe group. Triglyceride levels also decreased, but not overall cholesterol.
• In another small study of 40 patients with type 2 diabetes, scientists found that adding one tablespoon of aloe gel to the diabetes medication glyburide (a sulfonylurea) twice a day for 6 weeks significantly decreased fasting blood glucose. Triglyceride levels also decreased, but not overall cholesterol.
SIDE EFFECTS AND DRUG INTERACTIONS
There are many theoretical adverse effects of aloe. Patients should be cautious about low blood glucose when taking aloe in addition to diabetes medications such as insulin, sulfonylureas, and others.
In addition, patients should be cautious that an aloe product could be inadvertently contaminated with other parts of the plant that cause a laxative effect. For example, an ingredient found in aloe called anthraquinones was once included in over- the-counter laxatives. The FDA had concerns about fluid and electrolyte loss and had requested that manufacturers conduct further safety studies. Due to the excessive costs necessary to conduct these tests, manufacturers chose not to do the tests, and aloe is no longer allowed in nonprescription laxatives.
There are anecdotal reports of liver and kidney problems with high doses of aloe. Aloe should not be used by pregnant or breastfeeding women. There is concern that use during pregnancy may result in miscarriage and that some toxic substances may pass to the infant in breast milk.
There is the potential for prolonged bleeding when aloe is used with the anesthetic sevoflurane during surgery. Thus, aloe use should be stopped two weeks before surgery. Aloe should not be used with drugs that deplete potassium, such as certain diuretics. It should not be taken with the heart medication digoxin, since low potassium may result in dangerously high concentrations of digoxin.
OTHER 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)
