Complementary and Alternative Medicine (CAM) Supplement Use in People with Diabetes: A Clinician's Guide. Laura Shane-McWhorter

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СКАЧАТЬ when eaten cooked or taken as a dietary supplement. Although some individuals may prepare a blended shake using raw nopal, the raw stems may not lower blood glucose as effectively as when cooked. Nopal contains fiber and pectin, which may decrease carbohydrate absorption. The major side effects are diarrhea and increased stool volume. There are no long-term studies evaluating nopal for diabetes treatment. It is a benign agent and has been frequently consumed as a food. A frequently quoted dose is 100–500 g daily of broiled stems.¹⁹ An extract containing 1,500 IU taken prior to drinking large quantities of alcohol decreased hangover symptoms.¹⁰² For BPH, the dose used was 500 mg of powdered nopal flowers three times a day.¹⁰³ Optimal doses of extracts have not been established to treat diabetes; therefore caution should be exercised regarding recommendation of nopal supplements. As a food, however, it appears quite safe.

ALOE (Aloe Vera L.)

      Aloe is a member of the Liliaceae family. Derived from the Arabic alloeh, the name means “bitter and shiny substance.” Aloe grows well in Africa, the Mediterranean, the Caribbean, and warm areas of North and South America. Pictorial wall carvings of aloe have been found in Egyptian temples, and the Egyptian Book of Remedies (circa 1500 B.C.) notes the use of aloe to treat the skin and prepare drugs used as laxatives.⁷⁵ Dried aloe leaf juice has been used as a laxative, whereas topical aloe gels have been used to treat wounds, psoriasis, sebhorrhea, sunburn, and dry skin. Orally, aloe has also been used to enhance the immune system and treat diabetes and hyperlipidemia.⁷⁵ Aloe is highly used by Hispanic patients and may be called sábila.

      Chemical Constituents and Mechanism of Action

      Two forms of aloe are dried leaf juice and aloe gel.⁷⁵ Latex from the pericyclic cells obtained beneath the skin of leaves may be evaporated to form a sticky substance known as “drug aloes” or “aloe.” This aloe juice contains cathartics including anthraquinone, barbaloin, a glucoside of aloe-emodin, and other substances. Aloe gel, however, is the ingredient relevant to diabetes. It comes from the inner portion of leaves and does not contain cathartics, but it does contain the polysaccharide glucomannan, which is similar to guar gum.⁷⁵ Active ingredients include polysaccharides and glycoprotein, but although the definitive mechanism of action is unknown, the high fiber content alone may promote glucose uptake.¹⁰⁹

      Adverse Effects and Drug Interactions

      No adverse effects have been reported with aloe gel. One study evaluated renal and hepatic function, and there were no adverse effects.¹¹⁰ Aloe did not cause blood glucose to be excessively lowered when combined with the sulfonylurea glibenclamide (glyburide).¹¹⁰ Nevertheless, caution should be exercised by patients combining aloe with secretagogues. An unusual adverse effect was reported in a case of an individual taking aloe who experienced excessive intraoperative blood loss during surgery where sevoflurane was used. This may be due to the fact that both sevoflurane and aloe inhibit thromboxane A2, which may decrease platelet aggregation and prolong bleeding time.¹¹¹ There is also concern that inadvertent inclusion of aloe juice would produce a laxative effect and result in fluid or electrolyte disturbances.

      Clinical Studies

      In one very small uncontrolled study, five patients with type 2 diabetes were administered one-half teaspoonful dried aloe sap twice daily for 4–14 weeks.¹¹² Information regarding blinding was not provided. Fasting glucose decreased from a mean 273 mg/dl (15.2 mmol/l) to 151 mg/dl (8.4 mmol/l; P < 0.001). Mean A1C also decreased from 10.6% to 8.2% (P value not reported).

      A 6-week single-blind, placebo-controlled study was done in 40 patients with newly diagnosed type 2 diabetes.¹⁰⁹ Aloe vera juice was pre pared from aloe gel. The patients received 1 tablespoonful aloe gel twice daily or placebo for 6 weeks. Fasting blood measurements were taken weekly, and triglyceride and cholesterol levels were measured every 2 weeks. Fasting glucose declined significantly from 250 mg/dl (13.9 mmol/l) at baseline to 142 mg/dl (7.9 mmol/l) after 6 weeks in the aloe group (P = 0.01). Total cholesterol remained unchanged, but triglycerides declined from 220 mg/dl (2.5 mmol/l) to 123 mg/dl (1.4 mmol/l; P = 0.01).

      Another 6-week single blind controlled trial in 40 patients with type 2 diabetes evaluated the addition of 1 tablespoonful aloe gel or placebo twice daily to the sulfonylurea glibenclamide, 5 mg twice daily.¹¹⁰ Fasting glucose declined significantly from 288 mg/dl (16.0 mmol/l) to 148 mg/dl (8.2 mmol/l; P = 0.01 vs. control) in the aloe vera group. Total cholesterol remained the same: 230 mg/dl (5.95 mmol/l) at baseline and 226 mg/dl (5.80 mmol/l) after 6 weeks. However, triglycerides declined significantly from 265 mg/dl (3.0 mmol/l) to 128 mg/dl (1.5 mmol/l; P = 0.01 vs. control).

      Summary

      Aloe is a tropical plant used to treat type 2 diabetes. The active ingredients are thought to work as fiber to help stimulate cell glucose uptake. No adverse effects have been reported. However, there is concern that additive hypoglycemia may occur if aloe is combined with diabetes drugs. Also, there is a potential for prolonged bleeding with the anesthetic agent sevoflurane during surgery; thus aloe use should be discontinued 2 weeks before surgery. Three small studies have indicated that aloe may decrease fasting glucose and triglycerides, but not total cholesterol. No long-term information regarding aloe use is available, and the effect on A1C was reported in only one very small trial. The dose used has been 1 tablespoonful (15 ml) twice daily of aloe leaf gel.^109,110 Use of this supplement is not recommended because of the possibility of inadvertent contamination with some of the cathartic ingredients.

BANABA (Lagerstroemia speciosa L.)

      Banaba is a type of crape myrtle that grows in the Philippines, India, Malaysia, and Australia.¹¹³ Banaba is also known as queen’s crape myrtle, queen’s flower, and pride of India.⁷⁵ The tree is deciduous and has leathery leaves that turn red-orange in the fall. The tree has flowers that are a bright pink to purple and give way to nut-like fruits.⁷⁵ It has been used as a folk medicine in the Philippines, and a tea made from the leaves is used to treat diabetes.¹¹³ Other uses include purgative and diuretic actions from the leaf; and root constituents are used for stomach upset.⁷⁵ Recently, banaba has become popular in the U.S. It has been used for diabetes and weight loss, although information regarding long-term human use is not available. Information on weight loss is theorized from animal research because of effects on adipocyte differentiation.⁷⁵

      Chemical Constituents and Mechanism of Action

      Active ingredients include corsolic acid and tannins, including the ellagitannin lagerstroemin. Besides ellagitannins and lagerstroemin, flosin B and reginin A are thought to be glucose-transport enhancers.¹¹⁴ The ellagitannins are plant polyphenols, which reportedly bind to several polypeptides such as the regulatory subunit of protein kinase A. The active ingredients are thought to stimulate glucose uptake and have insulin-like activity. The latter activity is thought to be secondary to activation of insulin receptor tyrosine kinase or the inhibition of tyrosine phosphatase. Activation of tyrosine kinase causes tyrosine phosphorylation of several proteins, which then induce the functional change of signaling molecules such as phosphatidylinositol 3-kinase.¹¹⁵ Animal research has shown that banaba may inhibit alpha-amylase and alpha-glucosidases and thus СКАЧАТЬ