Nature's efficient pharmacy: herbs that help maintain normal blood sugar.

While the cause of diabetes isn't fully understood, this much is known: genetics and environmental factors such as obesity and lack of exercise play important roles. Also, diabetes usually involves elevated blood sugar levels resulting from either unbalanced levels of insulin or a reduction in its effectiveness.

Dietary guidelines exist to help manage blood glucose along with blood lipid levels. Abnormal blood lipids and cardiovascular disease are very often the primary cause of mortality associated with diabetes.

There are some herbal products that are useful adjuncts for lowering blood glucose levels or improving the utilization of insulin.

Fenugreek 

Powdered fenugreek seeds serve as an effective supportive therapy in the management of diabetes, especially among Indian populations. Fenugreek, with its spicy flavor, is a common ingredient in Indian curries. When taking only five grams of fenugreek a day, fasting and after-meal blood glucose levels were significantly reduced in persons with diabetes.

For those who are insulin dependent, a higher level of fenugreek is needed to significantly reduce fasting blood glucose levels, decrease urinary glucose levels, and cut daily insulin requirements.

Fenugreek seeds are reported to contain an unusual amino acid, that promotes insulin release from the pancreas. The ability of fenugreek to improve glucose tolerance is further enhanced by its rich content of a mucilaginous fiber, comprised mostly of galactomannans.

Prickly Pear

Prickly pear cactus (nopal) is a commonly used herbal substance by Mexican-Americans and American Indians for the treatment of type 2 diabetes and elevated blood cholesterol levels.

The cactus pads are prepared by slicing them into strips and boiling them like green string beans. The sweet, many-seeded, and fleshy fruit of prickly pear is also known as "cactus apple" or "tuna," and can be eaten raw or made into a drink.

Extracts of prickly pear cactus lower the blood sugar levels of animals with experimentally induced diabetes, as well as in healthy animals with elevated blood glucose levels. Patients with non-insulin-dependent diabetes mellitus who were given broiled nopal stems experienced a significant drop in blood glucose levels while their insulin became more effective.

The stems of prickly pear cactus contain substantial levels of soluble fiber such as pectin. The fiber content is believed to be responsible for the ability of the cactus to lower blood sugar and blood lipid levels. Broiling the cactus stems apparently increases its ability to lower blood glucose levels.

Cinnamon

Cinnamon has long been used in Korea and China as a traditional herb for treating people with diabetes. True cinnamon from Sri Lanka has a milder, sweeter flavor than the less expensive cassia variety widely used in the United States.

Cinnamon contains some water-soluble polyphenolic compounds derived from the antioxidant catechins. These compounds increase insulin sensitivity by enhancing insulin receptor function and glucose uptake. Cinnamon is also a good source of chromium, an essential trace mineral that augments the action of insulin.

Middle-aged men and women with type 2 diabetes who were daily given 1/2 teaspoon of cinnamon for six weeks experienced a 25 percent drop in fasting blood glucose levels, a 12 percent lowering of their blood cholesterol, and a 30 percent dip in blood triglyceride levels. Larger amounts did not improve the overall effectiveness of cinnamon with time.

Since the oily portion of cinnamon may be toxic in large amounts, it may be advisable to use the water-soluble extract in which the active polyphenolic compounds are retained but the oil constituents are removed. Without any changes in diet or physical activity, adults with pre-diabetes who were given 500 milligrams (1/6 teaspoon) of a water-soluble cinnamon extract daily for three months, experienced a 10 percent drop in fasting blood sugar.

Bitter Gourd

Bitter gourd is a green, cucumber-shaped tropical fruit with gourdlike bumps. It's eaten unripe like a vegetable and contains substances with antidiabetic properties such as charantin, vicine, polypeptide-p, and other bioactive components. Bitter gourd is also commonly known by other names such as "bitter melon," "wild cucumber," "balsam pear," and "karela."

Clinical trials involving type 2 diabetics have shown that fresh bitter gourd juice can effectively lower blood sugar levels and improve glucose tolerance. However, excessively high doses of bitter gourd juice may cause abdominal pain and diarrhea.

Karela capsules should be used with great caution, as a safe dosage has not been established. Diabetics taking hypoglycemic drugs or insulin should use a bitter melon product with caution, as it may increase the effectiveness of the drugs, leading to severe hypoglycemia.

Ginseng 

Asian ginseng is commonly used in traditional Chinese medicine to treat diabetes. In a well-controlled study, patients with type 2 diabetes who took 200 milligrams of Asian ginseng for eight weeks experienced improved fasting blood glucose levels and long-term glucose control. But beware. Ginseng is often contaminated with other substances and may lack standardization.

Gurmar

The leaves of Gurmar--a climbing vine in India have been effectively used in the management of type 1 and 2 diabetes mellitus. An extract of the leaves of Gurmar reduces insulin requirements or oral hypoglycemic drug dosages, reduces fasting blood glucose levels, and improves blood glucose control in individuals with diabetes possibly by enhancing the action of insulin.

Other Herbs of Interest

Preliminary studies have reported blood glucose-lowering activity or improved glucose tolerance from a number of other herbs, including garlic, onions, billberry, and psyllium seed. Further research is needed to validate these findings and discover if there is any clinical significance to the hypoglycemic effects of these herbs.

A new study reports the anti-diabetic effects of pine bark extract, marketed as pycnogenol. The polymeric procyanidins in pine bark inhibit the uptake of glucose by the small intestine. Both burdock and dandelion root contain inulin, which has a very mild beneficial effect on blood glucose control.

While no side effects have been reported with most of these botanical products, diabetic patients should be aware that the products may interfere with other therapies that control blood sugar.

Winston J. Craig, Ph.D., R.D., is professor of nutrition at Andrews University, Berrien Springs, Michigan.