Herbs & Nutrients for Glycaemic Control in Diabetes
Diabetes affects about 3% of the UK population and its incidence is increasing rapidly in all age groups. Type 1 diabetes is increasing in children, and type 2 diabetes is increasing particularly in black and minority ethnic groups. People of South Asian, African, African-Caribbean, and Middle-Eastern descent are at greater risk of type 2 diabetes, compared with the white population, as are the obese, those who are inactive or have a family history of diabetes.
Effectively controlled Type 2 diabetes can reduce the risk of heart disease by 44%, stroke by 46%, kidney disease by 33%, and eye disease by 33%. It could give people up to 10 years of additional life.
Blood sugar control can be best achieved with diets that are restricted in sugar, artificial sweeteners and refined carbohydrates with increased intakes of soluble fibre, together with increased levels of physical activity.
The preoccupation with fat over the last few decades is largely responsible for today’s obesity/diabetes crisis as people have substituted fat with sugar and refined carbohydrates. The average American now consumes 3 pounds of sugar a week.
Together with the right dietary and activity strategy, the natural therapist has a number of tools to help control blood sugar levels in type 2 diabetics.
In its trivalent form chromium is required for the maintenance of normal glucose metabolism. Deficiency is associated with impaired glucose tolerance which can be improved with supplementation.
Its action is linked with glucose tolerance factor, and has been shown to increase the number of insulin receptors, to enhance receptor binding, and to potentiate insulin action.
In one large trial following 833 diabetics for 10 months supplementing with chromium picolinate, investigators reported a decrease in fasting and postprandial glucose and a decrease in fatigue, excessive thirst and frequent urination. In another study of 180 people, 1mg of chromium picolinate a day for 2 months stabilised blood sugar.
Biotin aids in the management of blood sugar by enhancing the effect of enzymes involved in processing glucose.
There is limited evidence that high intakes of this vitamin can be therapeutically beneficial in diabetics and in rodent models of diabetes. One small study demonstrated a marked improvement in diabetic neuropathy after a few months on 5-10mg a day.
Biotin “might have considerable potential for promoting vascular health and preventing or managing diabetes.” (Med Hypotheses. 2006;66(2):323-8)
Coenzyme Q10 is believed to be able to improve glycaemic control through various mechanisms, including a decrease in oxidative stress. Two earlier randomised controlled trials using 100 to 200 mg of coenzyme Q10 in patients with type 1 or 2 diabetes found no difference in glycaemic control and insulin requirement. A more recent randomised controlled trial of 74 patients using 200 mg per day for 12 weeks found modest improvements in measurements of glucose control.
Conjugated Linoleic Acid
Data from a number of studies and trials have shown that different conjugated linoleic acids (CLA's) may produce beneficial effects in many areas including insulin resistance.
The mechanisms of action of CLAs are not fully clarified at present, because in vitro and in vivo studies are not always in agreement, and possibly because CLAs act in different ways and with different consequences when administered in the diet to different species.
“It may now be feasible to target specific supplemental nutrients to each of the key dysfunctions which conspire to maintain hyperglycemia in type 2 diabetes: bioactive chromium for skeletal muscle insulin resistance, conjugated linoleic acid for adipocyte insulin resistance, high-dose biotin for excessive hepatic glucose output, and coenzyme Q10 for beta cell failure. The nutrients and food factors recommended here appear to be safe and well tolerated, and thus may have particular utility for diabetes prevention.”
(Med Hypotheses 2000;54(3):483-7)
Low levels of magnesium are common among diabetics. Deficiency can potentially cause states of insulin resistance. It is a cofactor in various enzyme pathways involved in glucose oxidation, and it modulates glucose transport across cell membranes. It may improve insulin sensitivity. Dosage 300-600mg/day.
In animal models vanadium has been shown to facilitate glucose uptake and metabolism and to enhance insulin sensitivity. Human studies indicate it can greatly reduce the needs for insulin and hypoglycaemic medications. Dosage of vanadium sulphate is from 20mg/day.
Assists in insulin manufacture, may protect receptor sites on cell membranes that allows entry of the hormone, and helps balance blood sugar. May need 90mg/day or more.
Alpha Lipoic Acid
A potent antioxidant and cofactor in many enzyme complexes, it may also play a role in glucose oxidation. One trial of 74 patients reported positive effects on glucose uptake and insulin sensitivity with 600-1,800mg/day for 4 weeks. Particularly useful for treating polyneuropathy.
Glucose tolerance is improved with L-carnitine and diabetics eliminate much more L-carnitine than healthy people. Human trial data is very limited but one small short-term trial showed that intravenous administration can possibly affect insulin sensitivity and
enhance glucose uptake and storage.
Blood platelets of diabetics contain less vitamin E. Risk of acquiring diabetes is much greater among those with low levels of the vitamin. It improves sugar metabolism and supplementation can reduce the severity of diabetic complications.
Of 6 controlled trials, 4 were positive for glucose control with doses ranging from 100mg to 1,600mg a day for 2 to 4 months.
Elevated glycosylated haemoglobin is an indicator of diabetes-related harm. Vitamin B6 can reduce this indicator. It helps stabilise blood sugar, encourages cells to metabolise blood glucose and fights eye damage and vision loss from diabetic retinopathy. Dosage requirement is from 75mg/day.
Calcium, Vitamin D & Vitamin C
Calcium and vitamin D may help preserve insulin sensitivity by preventing secondary hyperparathyroidism. Vitamin C offers some protection against the effects of high blood sugar on the tissues and can also help control blood sugar levels in amounts over 2000mg/day.
Coccinia Indica (ivy gourd)
This plant grows in many parts of the Indian subcontinent and is used in Ayurveda. It appears to have insulin-mimetic properties.
The only randomised controlled trial of this herb reported significant changes in glycaemic control following 6 weeks use among 32 patients with poorly controlled or untreated type 2 diabetes. Anther trial found the magnitude of change seen with the herb was similar to a conventional drug. Two other trials offer supporting evidence of a hypoglaecemic effect
Reported mechanisms of action include decreased rate of carbohydrate absorption, increased glucose transport and uptake, increased glycogen storage and modulation of insulin secretion.
Two trials incorporating 24 and 36 patients for 8 weeks reported decreases in fasting blood sugar and better glucose control. Three other short-term trials in healthy volunteers found decreases in postprandial glucose. May need up to 200mg/day.
Another herb that grows in India and is used in Ayurveda. Animal studies have reported a glucose-lowering effect, regeneration of islets of Langerhans, and increases in serum insulin. Mechanism of action is unknown but a number of theories have been put forward.
Little trial data is available but 47 patients with type 2 diabetes showed improved glycaemic control in combination with conventional treatment. May need 100mg 3 times a day.
The dried sap of this plant is a traditional remedy for diabetes in the Arabian peninsula, although this form is also a laxative. Aloe gel may be a better tolerated choice. The gel contains glucomannan, a hydrosoluble fibre which may in part account for its hypoglycaemic effects.
Research in diabetes is sparse but two trials reported improved fasting blood glucose after 6 weeks of drinking juice made from the gel. There are also case reports of individuals with decreases in fasting blood glucose and improved glucose control.
This vegetable, also known as balsam pear, karela and bitter melon, is found in tropical areas of the world. Its active components include an insulin-like protein similar to bovine insulin.
Theoretical mechanisms include increased insulin secretion, tissue glucose uptake, liver muscle glycogen synthesis, glucose oxidation and decreased hepatic gluconeogenesis. Animal studies suggest hypoglycaemic effects.
Human studies are limited but report acute effects on blood glucose in the short term and positive effects on glycaemic control after longer term use.
Also known as prickly pear cactus, it is commonly used for glucose control by people of Mexican descent. It has a highly soluble fibre and pectin content which may affect intestinal glucose uptake, partially accounting for its hypoglycaemic actions.
Human studies reported improvements in patients with type 2 diabetes with decreased fasting glucose and decreased insulin levels, suggesting enhanced insulin sensitivity.
Animal experiments have shown moderate reductions in blood glucose and one high quality randomised controlled trial found significant decreases in fasting serum glucose. Another trial did not find consistent glucose or insulin responses.
Other herbs used for glycaemic control include holy basil, fenugreek, fig leaf, milk thistle and cinnamon.
One researcher concludes: “Nutraceuticals featuring meaningful doses of combinations of these agents would likely have substantial diabetes-preventive efficacy, and presumably could be marketed legally as aids to good glucose tolerance and insulin sensitivity.”
Med Hypotheses. 2005;64(1):151-8
This article was first published in Enzyme Digest No 72 2006
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