Coined back in 1980, the term diabesity has gained considerable traction during the past several years.1 Simply, diabesity refers to the interlaced epidemics of type 2 diabetes and obesity.
Being overweight or obese sets the stage for diabetes. In fact, gaining as little as 10 pounds of excess weight promotes insulin resistance, the hallmark of diabetes,2 and being obese (29 pounds or more over your ideal weight) boosts the risk of diabetes by 80 times.3 Diabetes and obesity significantly increase the risk of many other health problems, including inflammatory disorders, coronary artery disease, Alzheimer's and even some types of cancer.
The data paint a grim picture of public health. In the United States, two of every three adults are overweight or obese, and an estimated 100 million have some form of prediabetes. Twenty million people have type 2 diabetes, and that number now grows by 1 million each year. A recent report predicted that 86 percent of Americans will be overweight or obese, and the incidence of diabetes will increase 72 percent by 2030. In the United Kingdom, two of every three adults are also overweight or obese, and an estimated 13.6 percent of adults have diabetes.4
The prevalence of diabesity has also increased worldwide. The World Health Organization has reported that there are 1.7 billion overweight people in the world—almost three times those who are undernourished. An article in the New England Journal of Medicine predicts diabetes cases will increase by 32 percent in Europe, 164 percent in the Middle East, 150 percent in India, 104 percent in China and 148 percent in South America by 2030. Worldwide, an estimated 246 million people have diabetes, and some scientists conservatively expect that number to climb to 420 million in less than 20 years.5
What can be done to stem the tide—or rather, the tsunami? Improved eating habits are essential for normalizing weight and blood glucose, but many supplements ingredients can enhance insulin function, improve glucose tolerance, reduce appetite and help people lose weight.
Alpha-lipoic acid. Researchers at the University of Pennsylvania discovered in 1970 that this vitamin-like nutrient increases cellular uptake and burning of blood glucose.6 In the early 1990s, Germany approved alpha-lipoic acid (thioctic acid) as a prescription drug for the treatment of diabetic nerve disease. It serves as an antioxidant and enzymatic cofactor in the Krebs cycle and, in people, improves insulin function and sensitivity.7, 8, 9 Maintaining normal insulin sensitivity—that is, insulin function—is crucial for controlling blood glucose.
One animal study in South Korea found that alpha-lipoic acid might also help reduce appetite and weight and increase metabolism. The researchers found that alpha-lipoic acid regulates hypothalamic AMP-activated protein kinase (AMPK), which strongly influences appetite. Supplemental alpha-lipoic acid led to decreases in food intake and weight in laboratory rats.10
Alpha-lipoic acid consists of R and S isomers, but the R form is the biologically active isomer.11 Although available as an ingredient, R-lipoic acid is more expensive than alpha-lipoic acid.
Chromium. This essential dietary mineral enables insulin to transport glucose into cells. Symptoms of chromium deficiency—including elevated blood glucose, insulin, total cholesterol and triglyceride—resemble those of diabetes.
All forms of trivalent chromium seem to enhance glucose tolerance. However, research in recent years has focused on the chromium picolinate and chromium polynicotinate (niacin-bound) forms, both of which can significantly reduce blood-glucose and insulin levels.12 In one study, large doses (1,000 mcg) of chromium picolinate led to substantial decreases in blood-sugar and insulin levels after just four months.13 In another trial, supplements of niacin-bound chromium significantly decreased fasting blood sugar, with modest reductions in triglyceride and glycated hemoglobin (HbA1c) after three months.14, 15
The B vitamin biotin enhances the benefits of chromium. Biotin is required for the manufacture of insulin, and it regulates genes involved in the metabolism of glucose, amino acids and fatty acids.16 A recent study of 348 people found that a combination of these nutrients led to an average 6 percent decrease in fasting glucose.17 Doses up to 200,000 mcg (200 mg) have been found safe in people, and in one study, even doses as high as 20,000 mcg (20 mg) were completely absorbed.18
Pycnogenol. This proprietary antioxidant extract of French maritime pine bark can reduce fasting blood sugar by about 5 percent and postprandial blood sugar by about 10 percent.19, 20 It works in part by inhibiting alpha-glucosidase, a carbohydrate-digesting enzyme. This mechanism is similar to the diabetes drug acarbose, but experiments found Pycnogenol inhibited alpha-glucosidase 190 times better than acarbose.21 Pycnogenol also has cardio-protective and anti-inflammatory benefits important in reducing the risk of diabetic complications. It blocks the activity of the inflammation-promoting COX-2 enzyme.22 In a study of 30 patients with diabetes, European researchers found that Pycnogenol (50 mg, three times daily) reduced microcirculatory disease, which is involved in diabetic complications.23
Vitamin K. This vitamin is required for the carboxylation of osteocalcin, one of the key proteins in bones. In 2007, researchers discovered that osteocalcin also functions as a metabolic hormone, regulating pancreatic-beta-cell activity, insulin, glucose and the size of fat cells.24 Several human studies by Japanese researchers have found that vitamin K improves glucose tolerance. In 2008, researchers at Tufts University reported that supplements of vitamin K1 (500 mcg daily) led to significant improvements in fasting blood glucose and insulin after three years. The benefits, however, occurred in men but not women.25
Increasingly, attention is shifting from vitamin K1 to vitamin K2—specifically to the MK-4 and MK-7 forms of vitamin K2. Vitamin K2 appears to be better absorbed than vitamin K1. However, there have been no direct comparisons of MK-4 and MK-7 in human studies, so the preferred form is not yet known (note that vitamin K supplements are contraindicated in people taking vitamin K-antagonist anticoagulants, such as warfarin).
Vitamin D. Although vitamin D often seems like the latest miracle nutrient, its role in maintaining normal insulin function and glucose is well-established. Part of the credit goes to calcium, which is also required for normal insulin function, and vitamin D, also necessary for normal calcium utilization.26 A large clinical trial found that women who took 800 IU of vitamin D and 1,200 mg of calcium daily for 20 years were one-third less likely to develop diabetes. Another study found that people taking 700 IU of vitamin D and 500 mg of calcium daily had virtually no increase in blood-sugar levels during three years, whereas blood-sugar levels increased more than 6 mg/dl among people taking placebos.27
Resveratrol. Found in red wine and Japanese knotweed (Polygonum cuspidatum), resveratrol increases activity of SIRT, a principal anti-aging gene and one that also regulates insulin sensitivity.28 Mice given resveratrol maintained normal liver function and had relatively low levels of glucose, insulin and insulin-like growth factor-1(a polypeptide protein hormone similar in molecular structure to insulin).29 The average lifespan of the mice increased by about 15 percent, which may be related to both changes in gene function and lower levels of glucose and insulin.30 In a small, unpublished study of men with type 2 diabetes, researchers found that resveratrol reduced fasting blood glucose and improved insulin sensitivity.31 A study using 5 grams daily of resveratrol in the treatment of insulin resistance is currently underway at the University of California, San Francisco.32 Note that in 2007, GlaxoSmithKline paid $720 million to acquire Sirtris Pharmaceuticals, which has been researching resveratrol and developing similar synthetic molecules.33
Silymarin. This antioxidant extract of milk thistle (Silybum marianum) has long been used to enhance function of the liver, an organ that works in tandem with the pancreas to regulate blood glucose. Three clinical trials have clearly demonstrated the benefits of silymarin supplements in type 2 diabetes. In one of them, 51 patients with diabetes took 200 mg of silymarin three times daily for four months. The supplement led to a 15 percent decrease in blood glucose, a 13 percent decrease in glycated hemoglobin (HbA1C) and a 25 percent drop in fasting insulin levels.34 One of the other studies found a 20 percent decrease in fasting blood sugar, 37 percent decline in postprandial blood sugar and a 16 percent decrease in HbA1c—plus an 8.5 percent reduction in weight.35, 36, 37
Cinnamon. The research on cinnamon is conflicting, with some studies showing benefits and others not. In one of the positive studies, Richard A. Anderson, Ph.D., of the U.S. Department of Agriculture, and colleagues from Pakistan used cinnamon to treat 60 middle-age men and women with type 2 diabetes. After 40 days, fasting glucose decreased by 18 percent to 29 percent. In addition, cholesterol levels declined by 7 percent to 27 percent and triglyceride levels declined by 23 percent to 30 percent.38
Soluble fiber. Soluble fiber—the type that turns into a gel when mixed with water—includes glucomannan, inulin and pectin (Beta-glucan consists of both soluble and insoluble fibers). The gel increases a sense of fullness and decreases appetite. In an article in the American Journal of Clinical Nutrition, researchers analyzed 14 human studies on glucomannan, which is obtained from Amorphophallus konjac.39 Although glucomannan is best known for lowering cholesterol and triglyceride levels, it has impressive benefits in controlling blood glucose and weight. Daily glucomannan supplements were found to lower glucose by an average of 7.4 mg/dl after five weeks. In addition, supplements can promote a 1.7-pound weight loss over five weeks.40
Fenugreek. The seeds of this plant lower blood-glucose levels, and researchers have identified several possible mechanisms for the hypoglycemic effect. Fenugreek is rich in 4-hydroxyisoleucine, an amino acid that increases insulin secretion. It also inhibited the activity of two carbohydrate-digesting enzymes: alpha-amylase and sucrase.41 Fenugreek also contains both soluble and insoluble fiber, which slows carbohydrate absorption and boosts insulin activity.42 Clinical trials have found that fenugreek improves glucose tolerance in both type 1 and type 2 diabetes.43, 44
As always, retailers must evaluate the research on individual ingredients and work with shoppers to help them choose the right products.
Jack Challem is a personal nutrition coach in Tucson, Ariz. His latest book is Stop Prediabetes Now (Wiley, 2007). E-mail him with "NFM" in the subject line at [email protected]
References are available online at naturalfoodsmerchandiser.com.