Dietary Ingredients for Diabetes

The growing incidence of diabetes in the United States is alarming, to say the least. According to the 2011 National Diabetes Fact Sheet published by the Centers for Disease Control and Prevention (CDC), diabetes affects roughly 26 million Americans, including seven million who remain undiagnosed. Also, according to the CDC, as of 2010 an estimated 79 million American adults ages 20 or older could be considered pre-diabetic. (Pre-diabetes is a condition in which individuals have higher-than-normal blood glucose or hemoglobin A1c levels that aren’t yet high enough to be classified as diabetic.)

The situation, one would say, is serious. Diabetes is not only the leading cause of kidney failure and new cases of blindness among adults; it is also a major cause of heart disease and stroke.

According to the National Institutes of Health, the basic regimen for managing type 2 diabetes, also known as adult-onset diabetes, includes healthy eating-watching calorie and carbohydrate intake and increasing dietary fiber-as well as engaging in physical activity to control weight, and blood glucose monitoring. Consuming low-glycemic carbohydrates such as legumes, whole grains, nuts, and most fruits and vegetables is another tactic. Low-glycemic-index foods have been shown to release glucose more slowly and steadily, leading to more desirable post-meal blood glucose readings.

As for conventional prescription medications for diabetes, many are both expensive and may present potentially undesirable side effects if consumed over a prolonged period of time. As a result, a growing number of people are also choosing complementary and alternative medicinal approaches, incorporating a variety of dietary supplements and nutraceuticals in their diets.

Herbal Approaches

Cinnamon is one natural alternative proposed for lowering fasting blood glucose.

Integrity Nutraceuticals (Spring Hill, TN) says that its patented Cinnulin PF extract of the cinnamon plant Cinnamomum burmannii has been shown in clinical research to be beneficial in cases of metabolic syndrome or insulin resistance.(3) In a study by Ziegenfuss et al. in 2006, 83% of those given the active type-A polymers in Cinnulin PF experienced a significant decrease in fasting blood sugar (an approximate 8% drop), compared to only 33% of subjects in the placebo group. Lower systolic blood pressure values were also observed in patients.(4) The recommended dose for Cinnulin PF is 250 mg twice a day prior to meals.

Adding more recent research on cinnamon for diabetic conditions, a 2011 meta-analysis published in the Journal of Medicinal Food on the effects of cinnamon intake on people with type 2 diabetes and/or pre-diabetes showed that cinnamon intake, either as whole cinnamon or extract, resulted in a statistically significant lowering of fasting blood glucose.(5)

Salacia reticulata is also an herb that may help support healthy blood sugar levels. This herb contains mangiferin, a polyphenol that may enhance the body’s sensitivity to insulin.(6) Studies have also shown that the polyphenols in Salacia extract may have positive effects on weight loss by inhibiting fat-metabolizing enzymes and enhancing lipolysis (the breakdown of fat stored in fat cells).(7)

Another popular herb is Gymnema sylvestre. There are several theories on how the leaves of this herb pose positive benefits. Studies have shown that Gymnema may not only suppress the elevation of blood glucose levels by inhibiting glucose uptake from the intestine, but it may also reduce the body’s craving for sweets, thus making it an effective weight-loss tool. A 2010 study published in Phytotherapy Research showed that a high-molecular-weight extract from the plant was found to improve the symptoms of type 2 diabetes.(8)

Also used in herbal medicine, bitter melon (Momordica charantia) has been shown to increase insulin secretion and decrease hepatic gluconeogenesis. Additional research has suggested that this plant may also offer cardioprotective, antiviral, and anticancer properties.

Pterostilbene, an analog of resveratrol, is naturally present in Pterocarpus marsupium, the Indian Kino tree. A flexible-dose, open, 12-week clinical trial found Pterocarpus marsupium to be useful in controlling the blood glucose levels of newly diagnosed or untreated mild type 2 diabetes patients.(12) In a more recent flexible-dose, double-blind, multicenter, randomized controlled trial, Pterocarpus marsupium was determined to be an effective blood glucose–lowering agent for type 2 diabetes, free from any significant side effects in patients.(13)

Reza Kamarei, PhD, vice president of science and technology at Sabinsa Corp. (East Windsor, NJ), comments on the future potential of herbal approaches like pterostilbene in diabetes management. “It is interesting to see how these different plant extracts representing different classes of compounds and mechanisms of actions can work to alleviate some of the issues seen in type 2 diabetes.” (The company offers patented, natural pterostilbene ingredient Silbinol.)

Chromium

While research is still exploring chromium’s mechanisms in diabetes, it’s believed chromium may help control insulin activity by increasing insulin binding to cells.

InterHealth Nutraceuticals (Benicia, CA) provides Zychrome, which it describes as a unique, patent-pending chromium complex consisting of chromium, niacin, and L-cysteine (i.e., chromium dinicocysteinate). The company says it screened 17 chromium complexes in preclinical studies to arrive at what it says is the most efficacious chromium compound. It contends that both in vitro and in vivo studies have demonstrated that Zychrome is more efficacious than other forms of chromium in decreasing fasting glucose levels, glycated hemoglobin levels (HbA1c), insulin levels, vascular inflammation markers, and oxidative stress.(14)

“In a recent clinical trial comparing Zychrome to chromium picolinate and placebo, subjects consuming Zychrome experienced a statistically significant decrease in insulin resistance and insulin levels,” says James Lugo, PhD, director of research and business development for InterHealth.

“By contrast,” he continues, “no significant decrease in insulin resistance or insulin levels was observed among subjects supplementing with chromium picolinate or placebo. Zychrome also significantly reduced protein carbonyl and TNF-alpha levels [measures of oxidative stress and inflammation, respectively]. Overall, we were very pleased with the results as supplementation with Zychrome achieved a 30% decrease in insulin resistance.”

Fibers

Dietary fiber has long been touted as an important component of our diets, known to help with digestion as well as appetite control. While the World Health Organization recommends that people consume at least 25 g of dietary fiber per day, Western diets typically comprise far less than this amount.

For diabetes sufferers, dietary fiber can provide benefits, including slowing gastric emptying; preventing the rapid uptake of glucose from the small intestine, thus reducing postprandial blood sugar levels; and helping in the management of hypercholesterolemia. A high-fiber diet causes the body’s cells to be more sensitive to insulin and to either increase the number of insulin receptor sites or, alternatively, stimulate the cells’ ability to metabolize the glucose as fuel.

Fenugreek (Trigonella foenum-graecum) is an herb with well-documented properties for sugar and lipid control.(9,10) Fenugreek seeds contain a high level of dietary fiber (> 45%) in the forms of galactomannans, hemicellulose, pectin, cellulose, and lignins.

Preclinical and clinical studies have shown that the anti-diabetic action of fenugreek is associated with the defatted fiber-rich seed material. Its hypoglycemic effects have been attributed to 4-hydroxyisoleucine, which has been shown to stimulate insulin secretion in humans.(11)

Cargill (Minneapolis) has developed an all-natural source of soluble fiber in its ingredient Barliv, which comprises beta-glucan derived from barley. While Barliv is already backed by an FDA health claim for its cholesterol-lowering benefits, and the European Food Safety Authority (EFSA; Parma, Italy) also recently acknowledged the link between barley beta-glucan and cholesterol reduction in an article 14 health claim, Cargill says that a recent clinical trial showed that Barliv also has the potential to maintain healthy blood glucose levels.

A 12-week, randomized, double-blind, placebo-controlled clinical trial published in Nutrition & Metabolism in 2011 assessed the impact of Barliv on glucose levels and insulin sensitivity. Participants consumed three low doses (3 g fiber/day) or high doses (6 g fiber/day) in beverages along with their meals.

The results suggest that 6 g/day of Barliv fiber can improve insulin sensitivity among generally healthy people with pre-diabetes who have no prior diagnosis of diabetes mellitus and who experience no change in body weight.(15)

Hi-Maize Resistant Starch

Another ingredient that may help in managing healthy blood sugar levels is Hi-maize resistant starch. Resistant starch is described as starch that resists digestion in the small intestine and reaches the large intestine.

“While this ingredient has more than 70 human clinical trials supporting its beneficial health effects, it has only recently been gaining the attention of health-conscious consumers for its blood sugar benefits,” says Rhonda Witwer, senior business development manager of nutrition, National Starch Food Innovation (Bridgewater, NJ).

Consumption of resistant starch has been shown to improve insulin sensitivity in patients with metabolic syndrome (19% improvement over a 12-week period).16 Hi-maize resistant starch contains approximately 40% slowly digestible starch, which is digested within the small intestine and slowly absorbed as glucose. Hi-maize resistant starch also comprises approximately 60% resistant starch, which is not digested in the small intestine. The resistant starch portion reaches the large intestine, where it is fermented by the beneficial bacteria to produce the short-chain fatty acids. These short-chain fatty acids trigger additional beneficial metabolic changes, including the production and release of hormones related to satiety and insulin from the large intestine.

Post-Carb Approaches

Pharmachem Laboratories (Kearny, NJ) has developed a standardized extract of the white kidney bean (Phaseolus vulgaris), called Phase 2 Carb Controller, which acts to prevent the breakdown of dietary starch. The slower absorption of carbohydrates would have a beneficial effect on the rate and extent of insulin release.

A recent study showed that when subjects consumed four slices of white bread and margarine with or without Phase 2, glucose absorption, as measured by the area under the plasma glucose versus time curve, was inhibited by 66% in the Phase 2 group. Accordingly, only one-third of the carbohydrates in the bread were absorbed. Also, plasma glucose levels returned to baseline earlier than the control.(18)

Mitch Skop, Pharmachem’s director of new product development, says, “Phase 2 has been shown in multiple studies to [help with] parameters of metabolic syndrome. While it is not a panacea, it’s a very good first step in a well-designed health program.” 

InSea2 is another ingredient being explored for how it may help manage insulin levels after consumption of a carbohydrate-rich meal. The ingredient is a blend of brown seaweed (Ascophyllum nodosum and Fucus vesiculosus).

A double-blind, randomized, placebo-controlled crossover study published in Applied Physiology, Nutrition, and Metabolism this past December on 23 men and women examined the effects of InSea2-two 250-mg capsules versus placebo-on plasma glucose and insulin concentrations following consumption of 50 g of carbohydrates from bread.(19) According to researchers, InSea2-supplemented subjects experienced a small but significant reduction in post-load plasma insulin concentrations, as well as an acute improvement in insulin sensitivity.

InSea2’s brown seaweed constituents are said to inhibit both alpha-amylase and alpha-glucosidase activities, which are involved in the digestion of dietary starch and carbohydrates. By inhibiting these enzymes, InSea2 reduces carbohydrate absorption and as a result may help maintain glycemic control and healthy insulin levels.

References

1. Jarvill-Taylor KJ et al. “A hydroxychalcone derived from cinnamon functions as a mimetic for insulin in 3T3-L1 adipocytes.” Journal of the American College of Nutrition, vol. 20, no. 4 (August 2001): 327-362.

2. Anderson RA et al. “Isolation and characterization of polyphenol type-A polymers from cinnamon with insulin-like biological activity.” Journal of Agricultural & Food Chemistry,vol. 52, no. 1 (January 14, 2004): 65-70.

3. Wang JG et al. “The effect of cinnamon extract on insulin resistance parameters in polycystic ovary syndrome: a pilot study.” Fertility and Sterility,vol. 88, no. 1 (July 2007): 240-243.

4. Ziegenfuss TN et al. “Effects of a water-soluble cinnamon extract on body composition and features of the metabolic syndrome in pre-diabetic men and women.” Journal of the International Society of Sports Nutrition,vol. 3 (December 28 2006): 45-53.

5. Davis PA and Yokoyama W. “Cinnamon intake lowers fasting blood glucose: meta-analysis.” Journal of Medicinal Food,vol. 14, no. 9 (September 2011): 884-889.

6. Yoshikawa M et al. “Hepatoprotective and antioxidative properties of Salacia reticulata:preventive effects of phenolic constituents on CCl4-induced liver injury in mice.” Biological and Pharmaceutical Bulletin, vol. 25, no. 1 (January 2002): 72-76.

7. Yoshikawa M et al. “Salacia reticulataand its polyphenolic constituents with lipase inhibitory and lipolytic activities have mild antiobesity effects in rats.” Journal of Nutrition,vol. 132, no. 7 (July 2002):1819-1824.

8. Al-Romaiyan A et al. “A novel Gymnema sylvestreextract stimulates insulin secretion from human islets in vivoand in vitro.”Phytotherapy Research,vol. 24, no. 9 (September 2010): 1370-1376.

9. Roberts KT. “The potential of fenugreek (Trigonella foenum-graecum) as a functional food and nutraceutical and its effects on glycemia and lipidemia.” Journal of Medicinal Food,published online ahead of print August 23, 2011.

10. Prabhakar PK and Doble M. “Mechanism of action of natural products used in the treatment of diabetes mellitus.” Chinese Journal of Integrative Medicine, vol. 17, no. 8 (August 2011): 563-574.

11. Sauvaire Y et al. “4-Hydroxyisoleucine: a novel amino acid potentiator of insulin secretion.” Diabetes,vol. 47, no. 2 (February 1998): 206-210.

12. Indian Council of Medicinal Research (ICMR). “Flexible dose open trial of Vijayasar in cases of newly-diagnosed non-insulin-dependent diabetes mellitus.” Indian Journal of Medical Research,vol. 108 (July 1998): 24-29.

13. ICMR Study Group. “Efficacy of Vijayasar (Pterocarpus marsupium)in the treatment of newly diagnosed patients with type 2 diabetes mellitus: A flexible dose double-blind multicenter randomized controlled trial.” Diabetlogica Croatica,vol. 34, no. 1 (2005): 13-20.

14. Jain SK et al. “Chromium dinicocysteinate supplementation can lower blood glucose, CRP, MCP-1, ICAM-1, creatinine, apparently mediated by elevated blood vitamin C and adiponectin and inhibition of NF-kB, Akt, and Glu-2 in livers of zucker diabetic fatty rats.” Molecular Nutrition and Food Research,vol. 54, no. 9 (September 2010): 1371-1380.

15. Bays H et al. “Reduced viscosity Barley b-glucan versus placebo: A randomized controlled trial of the effects on insulin sensitivity for individuals at risk for diabetes mellitus.” Nutrition and Metabolism,(August 2011); 8: 58.

16. Vinson JA et al. “Investigation of an amylase inhibitor on human glucose absorption after starch consumption.” The Open Nutraceuticals Journal,vol. 2 (2009): 88-91.

17. Johnston KL et al. “Resistant starch improves insulin sensitivity in metabolic syndrome.” Diabetic Medicine,vol. 27, no. 4 (April 2010): 391-397.

18. Chambers E et al. “Dietary starch and fiber: potential benefits to body weight and glucose metabolism.” Diabetes Management,vol. 1, no. 5 (September 2011): 521-528.

19. Paradis ME et al., “A randomized crossover placebo-controlled trial investigating the effect of brown seaweed (Ascophyllum nodosum and Fucus vesiculosus) on postchallenge plasma glucose and insulin levels in men and women,” Applied Physiology, Nutrition, and Metabolism, vol. 36, no. 6 (December 2011):913-9.