By Gene Bruno, MS, MPH
Several dietary supplements have the potential to help reduce blood glucose and A1C levels in diabetics. Most studies on these supplements were conducted on type-2 diabetics; however, given the mechanism of actions of these nutrients, they would likely be beneficial for either type-1 or -2 diabetics.
Alpha-Lipoic Acid
Alpha-lipoic acid (ALA) is a natural antioxidant manufactured by the body and similar to certain vitamins. Unlike most other antioxidants, however, it has the advantage of being soluble in both fat and water, so it can provide production both inside and outside of cells.1 ALA is also found in some foods, particularly liver and yeast.
In a placebo-controlled, multicenter study, 74 patients with type 2 diabetes were given either a placebo or 1,800 mg/d ALA.2 When compared to the placebo group, those receiving ALA had significantly greater insulin sensitivity (reflecting improvement in insulin resistance), and reduced glucose levels. In other research, oral or intravenous use of ALA improved insulin sensitivity and reduction of glucose levels in patients with type-2 diabetes.3,4,5 Skin rash has been reported in some individuals after oral consumption of ALA.6 Theoretically, use with other hypoglycemic drugs might cause additive blood sugar lowering effects.7
Chromium
Chromium is an essential trace mineral whose function in the body is to work with insulin to help transport glucose and maintain healthy glucose levels. Chromium levels can be below normal in patients with diabetes.8,9 In a randomized, placebo-controlled study, 180 men and women with type-2 diabetes were divided into three groups and supplemented with: 1) placebo, 2) 200 mcg/d chromium picolinate or 3) 1,000 mcg/d chromium picolinate.10 Subjects continued to take their normal medications and were instructed not to change their normal eating and living habits. Both doses of supplemental chromium had significant beneficial effects on A1C, glucose, insulin and cholesterol, although the benefits were greater with the higher dose. Other studies also show taking chromium picolinate orally can decrease fasting blood glucose, decrease A1C levels, decrease triglyceride levels and increase insulin sensitivity in people with type-2 diabetes.11,12 Some evidence also suggests chromium picolinate might decrease weight gain and fat accumulation in type 2 diabetes patients who are taking a sulfonylurea (i.e., anti-diabetic drugs that act by increasing insulin release from the beta cells in the pancreas).13
Higher chromium doses (1,000 mcg/d) might be more effective and work more quickly.14 Higher doses might also reduce triglyceride and total serum cholesterol levels in some patients.15,16 Additional research demonstrated chromium picolinate also improved glucose levels in patients with type-1 diabetes, as well as gestational and steroid-induced diabetes.17,18,19,20 Theoretically, use with other hypoglycemic drugs might cause additive blood sugar lowering effects.21 Taking 1,000 mcg chromium picolinate with 1 mg levothyroxine has been shown to decrease serum levels of levothyroxine by 17 percent compared to taking levothyroxine alone,22 so levothyroxine should be taken at least 30 minutes before or three to four hours after taking chromium.
Biotin
Biotin is a B vitamin that plays various important functions, including helping the body form glucose from sources other than carbohydrates. A combination of biotin and chromium may lower blood glucose and A1C levels in type-2 diabetes patients who are poorly controlled on oral hypoglycemic drugs, according to one randomized, double blind, placebo-controlled study.23 In the trial, 447 subjects with poorly controlled type-2 diabetes received either 600 mcg/d chromium picolinate and 2 mg/d biotin, or placebo, for 90 days in combination with stable oral anti-diabetic agents. Results demonstrated significant reduction in A1C and fasting glucose levels compared to placebo. Another randomized, double blind, placebo-controlled study in type-2 diabetics using the same doses showed similar benefits.24 Biotin alone, however does not seem to affect glucose or insulin levels in people with type 2 diabetes.25 Biotin is well tolerated when used at recommended dosages, and doses of 10 mg/d have been taken without adverse effects.
Panax ginseng
In Asian countries, the fleshy root of Panax ginseng is considered a tonic, stimulant and stress adaptogen. More than 500 studies have been published on ginseng. Perhaps best known among ginseng’s major properties are its ability to improve mental and physical performance and well-being in a variety of circumstances. In addition, this classic herbal medicine has benefits for diabetics.
In a double blind, placebo-controlled study, 36 type-2 diabetics were treated for eight weeks with ginseng (100 or 200 mg/d) or placebo.26 Ginseng therapy improved mood, improved mental and physical performance, and reduced fasting blood glucose and body weight. The 200-mg dose of ginseng improved A1C and physical activity. Placebo reduced body weight and altered the serum lipid profile, but did not alter fasting blood glucose. Likewise, in a 12-week, double blind, randomized, crossover study, 19 type-2 diabetics were supplemented with 6 g/d Panax ginseng as an adjunct to their usual anti-diabetic therapy (diet and/or medications).27 Good blood glucose control was maintained throughout, and fasting glucose levels were reduced, while fasting insulin levels were increased. Orally, Panax ginseng is usually well tolerated. Theoretically, concurrent use with anti-diabetic drugs might enhance blood glucose lowering effects.28 Also theoretically, concurrent use might interfere with immunosuppressive therapy since Panax ginseng might have immune system stimulating properties.29
Milk Thistle
Milk thistle is, arguably, the best herbal medicine for liver health. The active components in milk thistle are its flavonoids, collectively called silymarin; the majority of milk thistle-related research has been conducted on this component. Silymarin has primarily been studied and recognized for its ability to benefit people with liver disorders, although it has benefits for diabetics as well. Taking 600 mg/d silymarin for four months, in combination with conventional treatment, significantly decreased fasting blood glucose, A1C, total cholesterol, low-density lipoprotein (LDL) cholesterol and triglycerides compared to placebo in patients with type 2 diabetes.30 Other research has shown the same dose of silymarin daily reduced insulin resistance in people with coexisting diabetes and alcoholic cirrhosis.31 Orally, milk thistle is usually well-tolerated.
Cinnamon
The smell and taste of cinnamon in a warm, gooey cinnamon bun is probably enjoyable to just about everyone you know. Unfortunately, the gooey bun is not a particularly good choice for diabetics; but, it turns out the cinnamon may actually provide some significant health benefits. While the majority of clinical research shows whole cinnamon powder is not effective for type 1 or type 2 diabetes,32 two studies conducted on a specific water-soluble cinnamon extract both showed consistent beneficial results. A placebo-controlled, double blind study was conducted on 79 patients with type 2 diabetes.33 Subjects were given 336 mg/d of a water-soluble cinnamon extract (corresponding to 3 g of cinnamon powder) or a placebo for four months. Those using the cinnamon experienced a significant 10.3-percent reduction in fasting blood sugar, compared to a non-significant 3.4 percent reduction in the placebo group.
In another placebo-controlled, double blind study, 21 adults with metabolic syndrome (i.e., prediabetes) were given a water-soluble cinnamon extract (500 mg/d) or a placebo for 12 weeks.34 Eighty-three percent of those given the extract experienced a significant decrease (about 8 percent) in fasting blood sugar, compared to only 33 percent in the placebo group who experienced a decrease. In addition, the cinnamon subjects also experienced a significant alteration in body composition. Their body fat decreased by 0.7 percent, and their muscle mass increased by 1.1 percent. These changes took place without alterations in the diet or physical activity of the subjects.
Gymnema
Gymnema is an Ayurvedic botanical with a long history of use for treating diabetes. In an open-label study, 22 type 2 diabetic patients received 400 mg/d gymnema extract for 18 to 20 months, as a supplement to the conventional oral drugs.35 Subjects showed a significant reduction in blood glucose, A1C and other glycosylated blood proteins. In addition, conventional drug dosage could be decreased. Five of the 22 subjects were able to discontinue their use of conventional drugs and maintain their blood glucose homeostasis with gymnema extract alone. The researchers suggested the results may have been due to beta cell regeneration/repair, as supported by the appearance of raised insulin levels in the serum of patients after supplementation.
In a similar study, the same dose of gymnema extract was administered to 27 patients with type 1 diabetes, who were also on insulin therapy.36 Insulin requirements came down together with blood glucose and A1C and glycosylated blood protein levels. Blood fats also returned to near normal levels with gymnema therapy. Type 1 diabetic patients who were on insulin therapy alone showed no significant reduction in serum lipids, A1C or glycosylated blood protein when followed up after 10 to 12 months. Gymnema can enhance the blood glucose lowering effects of insulin and hypoglycemic drugs.
Pycnogenol®
Pycnogenol® is the trade name of a bioflavonoid derived from the bark and needles of the pine tree Pinus maritima. This patented bioflavonoid contains the powerful group of antioxidants called oligomeric proanthocyanidins (OPC). As an antioxidant, OPC are 50 times more effective than vitamin E and 20 times as strong as vitamin C. In addition, Pycnogenol may have benefits for diabetics.
In an open, controlled, dose-finding study, 30 type 2 diabetics were given 50, 100, 200 and 300 mg/d Pycnogenol in three-week intervals for a total of 12 weeks.37 Doses of 100 to 300 mg/d lowered fasting glucose significantly, while 50 mg/d significantly lowered glucose levels after a meal; 300 mg/d had no stronger effect. A1C levels decreased continuously with a significant difference after nine and 12 weeks with 200 or 300 mg Pycnogenol. Another double blind, placebo-controlled, randomized, multi-center study was performed with 77 type-2 diabetics given placebo or 100 mg Pycnogenol for 12 weeks, during which standard anti-diabetic treatment was continued.38 The results were significantly lowered plasma glucose levels as compared to placebo. A1C was also lowered, although the difference as compared to placebo was statistically significant only for the first month.
While ALA, chromium and biotin, Panax ginseng, milk thistle, cinnamon, gymnema and Pycnogenol are not the only nutrients that have potential for reducing glucose and A1C levels in diabetics, they are the ones that seem to have the most data to support their use, as well as the least adverse effects or interactions. Certain other supplements that are popular for this purpose sometimes lack good human clinical studies to substantiate their use, or their potential adverse effects tend to make them risky for diabetics.
For a list of references, email NPMreferences@vpico.com.





