by Jay Udani, M.D.
As the population ages, it also expands—at the waistline. The global obesity epidemic is the prelude to the coming diabetes epidemic, and people worldwide will be looking for natural health products to assist in the management of this condition.
The list of natural ingredient purported to manage blood sugar is long and full of opportunity. These ingredients have been used traditionally for prevention and as an adjunct to management of impaired glucose tolerance. They can also be used in combination with allopathic therapies in synergistic ways.
The path from obesity to diabetes is not a straight line. Several mechanisms are involved, and natural health products have the ability to influence them all. Prevention and treatment strategies include reversing the decline in adiponectin, increasing insulin sensitivity, reducing inflammation, reducing oxidative stress, enhancing glycemic control and reducing weight.
First, consider the issue of raising adiponectin levels. Ingredients known as PPAR-gamma agonists have been shown as a class to increase adiponectin levels. They have a synergistic effect with insulin, and reduce inflammation in the liver, adipose and vascular tissues (Gervois et al. 2004; Hseuh et al. 2003). Of the products with known PPAR-gamma activity, none have been demonstrated to show significant increases in adiponectin in humans. These products, including bitter melon, mulberry leaf, Korean red ginseng, banaba, Punica granatum and turmeric, show promise, but further study is necessary before they can be recommended specifically for treatment of low adiponectin.
Next, address increasing sensitivity to insulin, the primary hormone of blood sugar control. Ingredients that stimulate the production of insulin or mimic its effects can be effective in the regulation of blood sugar. A partial list of these ingredients includes bitter melon (Momordica charantia), Gymnema sylvestre, cinnamon and green tea. Bitter melon contains an insulin-like peptide called p-insulin (for plant insulin), which is structurally similar to mammal insulin. Human studies on bitter melon are encouraging, but have been uncontrolled and have used very high doses (up to 57 g/d). Gymnema sylvestre has been shown to increase insulin secretion, and may temporarily dull the ability to taste sweets, which may reduce sugar intake (Sivastava et al. 1993). Cinnamon studies have shown improvements in glucose and insulin modulation, but when five of the highest quality studies were combined for a meta-analysis, the benefits did not hold up (Baker et al. 2007). Green tea has been shown to increase insulin sensitivity by 13 percent in healthy volunteers (Venables et al. 2008) and reduce HbA1c compared with placebo (Fukino et al. 2008).