Also known as adult-onset diabetes, type 2 diabetes can
often be managed by carefully monitoring your diet. According to research or other evidence,
the following self-care steps may be helpful:
Aim for total nutrition with a multivitamin
Help ensure your body is getting the vitamins and minerals it
needs to help prevent common infections
Check out chromium
Improve glucose tolerance by taking 200 to 1,000 mcg of this
essential trace mineral every day
Fight back with fiber
Under a doctor's supervision, stabilize your blood sugar by eating
fiber from whole grains, beans (legumes), vegetables, and fruit, and consider using a fiber
supplement such as glucomannan or psyllium
Use a topical ointment
An ointment containing 0.025 to 0.075% capsaicin four times a day
might help control nerve pain
Talk to your doctor
Ask about oral medications that are commonly prescribed to people
with type 2 diabetes, such as glipizide (Glucotrol), glimepiride (Amaryl), glyburide (DiaBeta,
Micronase), metformin (Glucophage), rosiglitazone (Avandia), and pioglitazone (Actos), as well
as insulin injections (Humulin N, Humulin R, Humalog, Novolog, Lantus)
These recommendations are not comprehensive and are not intended to replace
the advice of your doctor or pharmacist. Continue reading the full diabetes article for more
in-depth, fully-referenced information on medicines, vitamins, herbs, and dietary and
lifestyle changes that may be helpful.
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About
Product ratings
Dietary changes
Lifestyle changes
Vitamins
Herbs
Holistic options
References
About diabetes
Diabetes mellitus is an inability to metabolize carbohydrates resulting from inadequate
insulin production or utilization. Other forms of diabetes (such as diabetes insipidus) are
not included in this discussion.
There are two types of diabetes mellitus, type 1 and type 2. This article concerns type 2
diabetes, which has also been called adult-onset diabetes or non-insulin-dependent diabetes.
However, type 2 diabetes may also affect children and may also require treatment with insulin.
With type 2 diabetes, the pancreas often makes enough insulin, but the body has trouble using
it. Type 2 diabetes frequently responds well to natural therapies.
People with diabetes cannot properly process glucose, a sugar the body uses for energy. As
a result, glucose stays in the blood, causing blood glucose to rise. At the same time,
however, the cells of the body can be starved for glucose. People with diabetes are at high
risk for heart disease, atherosclerosis, cataracts, retinopathy, stroke, poor wound healing, infections, and damage to the kidneys and nerves. In
addition, those with diabetes have a higher mortality rate if they also have high homocysteine levels.1
Product ratings for diabetes
mellitus
Science Ratings
Nutritional Supplements
Herbs
Alpha lipoic acid
Brewer’s yeast
(providing approximately 60 mcg of chromium per tablespoon)
Vitamin B1 (thiamine;
in combination with vitamin B6 or B12 for diabetic neuropathy only)
Vitamin B12 (for
diabetic neuropathy)
Vitamin B6
Vitamin C
Vitamin D
Vitamin E (for
prevention of diabetic retinopathy)
Zinc (for deficiency
only)
Aloe
American ginseng
Asian ginseng
Bilberry
Bitter melon
Cinnamon
Crepe myrtle (Lagerstroemia speciosa)
Gymnema
Hairy basil (seed)
Holy basil (leaf)
Milk thistle
Onion
Fish oil (EPA/DHA)
Following are associated with diabetic retinopathy: selenium,
vitamin A, vitamin C, and vitamin E (combined)
Fructo-oligosaccharides (FOS)
Inositol
Manganese
Medium-chain
triglycerides
Quercetin
Starch blockers
Taurine
Vanadium
Vitamin B3
(niacin)
Vitamin E (associated
with abetalipoproteinemia)
Açaí
Ginkgo
Hibiscus
Mistletoe
Olive leaf
Reishi
Reliable
and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies
suggesting a health benefit or minimal health benefit. For an herb, supported by traditional use but minimal
or no scientific evidence. For a supplement, little scientific support and/or minimal health
benefit.
Dietary changes that may be helpful
The relationship between eating carbohydrates and type 2 diabetes is complex. While eating
carbohydrates increases the need for insulin to keep blood sugar normal, diets high in total
carbohydrates do not necessarily increase the risk of type 2 diabetes.2
3 Researchers have found that diets very high in sugar may worsen glucose tolerance in
nondiabetic animals and humans.45 However, the amount of sugar used in
these studies in proportion to other foods was much larger than is typically found in human
diets.
Eating carbohydrate-containing foods, whether high in sugar or high in starch (such as
bread, potatoes, processed breakfast cereals, and rice), temporarily raises blood sugar and
insulin levels.6 The blood sugar–raising effect of a food, called its
“glycemic index,” depends on how rapidly its carbohydrate is absorbed. Many
starchy foods have a glycemic index similar to table sugar (sucrose).7 People
eating large amounts of foods with high glycemic indexes have been reported to be at increased
risk of type 2 diabetes. 89 On the other hand, eating a diet high in
carbohydrate-rich foods with low glycemic indexes is associated with a low risk of
type 2 diabetes. 101112 Beans, peas, fruit, and oats have low glycemic indexes, despite their high
carbohydrate content, due mostly to the health-promoting effects of soluble fiber.
Diabetes disrupts the mechanisms by which the body controls blood sugar. Until recently,
health professionals have recommended sugar restriction to people with diabetes, even though
short-term high-sugar diets have been shown, in some studies, not to cause blood sugar
problems in people with diabetes.131415 Currently, the
American Diabetic Association (ADA) guidelines do not prohibit the use of moderate amounts of
sugar,16 as long as blood levels of glucose, triglycerides, and cholesterol are maintained within normal levels.
Most doctors recommend that people with diabetes to reduce the amount of sugar eaten in
snacks and processed foods, and replace these foods with high-fiber, whole foods. This tends to lower the glycemic
index of the overall diet and has the additional benefit of increasing vitamin, mineral, and
fiber intake. Other authorities also recommend lowering the glycemic index of the diet to
improve the control of diabetes.17
A high-fiber diet has been shown to work
better in controlling diabetes than the diet recommended by the ADA, and may control blood
sugar levels as well as oral diabetes drugs.18 In this study, the increase in
dietary fiber was accomplished exclusively by eating foods naturally high in fiber—such
as leafy green vegetables, granola, and fruit—to a level beyond that recommended by the
ADA. No fiber supplements were given. All participants received both the ADA diet (providing
24 grams of fiber per day) and the high-fiber diet (providing 50 grams of fiber per day) for a
period of six weeks. After six weeks of following each diet, tests were performed to determine
blood glucose, insulin, cholesterol, triglyceride, and other values. When glucose levels were
monitored over a 24-hour period, participants eating the high-fiber diet had an average
glucose level that was 10% lower than participants eating the ADA diet. Insulin levels were
12% lower in the group eating the high-fiber diet compared to the group eating the ADA diet,
indicating a beneficial increase in the body’s sensitivity to insulin. Moreover, people
eating the high-fiber diet experienced significant reductions in total cholesterol,
triglycerides, and LDL (“bad”) cholesterol compared with those eating the ADA
diet. They also had slight decreases (improvements) in glycosylated hemoglobin levels, a
measure of long-term blood glucose regulation.
High-fiber supplements, such as
psyllium,19 guar gum (found in cluster beans),20 pectin (from
fruit),21 oat bran,22 and
glucomannan,2324 have improved glucose tolerance in some studies.
Positive results have also been reported with the consumption of 1 to 3 ounces of powdered fenugreek seeds per day.25
26 A review of the research revealed that the extent to which moderate amounts of fiber
help people with diabetes in the long term is still unknown, and the lack of many long-term
studies has led some researchers to question the importance of fiber in improving
diabetes.27 Nonetheless, most doctors advise people with diabetes to eat a diet
high in fiber. Focus should be placed on fruits, vegetables, seeds, oats, and whole-grain products.
Eating fish also may afford some protection from diabetes.28 Incorporating a
fish meal into a weight-loss regimen was more
effective than either measure alone at improving glucose and insulin metabolism and high
cholesterol.29
Vegetarians have been reported to have a
low risk of type 2 diabetes.30 When people with diabetic nerve damage switch to a
vegan diet (no meat, dairy, or eggs), improvements have been reported after several
days.31 In one trial, pain
completely disappeared in 17 of 21 people.32 Fats from meat and dairy may also
contribute to heart disease, the leading
killer of people with diabetes.
Vegetarians also eat less protein than do meat eaters. Reducing protein in the diet has
lowered kidney damage caused by diabetes and may also improve glucose tolerance.3334 and may also improve glucose tolerance.35 However, in a group of 13
obese males with high blood-insulin levels (as is often seen in diabetes), a high-protein,
low-carbohydrate diet resulted in greater weight loss and control of insulin levels, compared
with a high-carbohydrate diet.36 Switching to either a high- or low-protein diet
should be discussed with a doctor.
Diets high in fat, especially saturated fat, worsen glucose tolerance and increase the risk
of type 2 diabetes,37383940 an effect that is
not simply the result of weight gain caused by eating high-fat foods. Saturated fat is found
primarily in meat, dairy fat, and the dark meat and skins of poultry. In contrast, glucose
intolerance has been improved by diets high in monounsaturated oils,41
42 which may be good for people with diabetes.43 The best way to incorporate
monounsaturates into the diet is to use olive oil, especially extra virgin olive oil, which
has high antioxidant values.
Lifestyle changes that may be helpful
Most people with type 2 diabetes are overweight.44 Excess abdominal weight does
not stop insulin formation,45 but it does make the body less sensitive to
insulin.46 Excess weight can even make healthy people prediabetic,47
though weight loss can reverse this
problem.48 In most studies, type 2 diabetes has improved with weight
loss.495051
Exercise helps decrease body fat and improve insulin sensitivity.52
53 People who exercise are less likely to develop type 2 diabetes than those who do
not.54 However, exercise can induce low
blood sugar in diabetics taking blood sugar–lowering medications, or even
occasionally increased blood sugar.(55 Therefore, people with diabetes
should never begin an intensive exercise program without consulting a healthcare
professional.
Moderate alcohol drinking in healthy people improves glucose
tolerance.56575859 However, alcohol has been
reported to worsen glucose tolerance in the elderly and in people with diabetes in some
studies.6061 People with diabetes who drink have also been reported to
have a high risk for eye and nerve damage.6263
Questions remain about where the line should be drawn regarding alcohol intake. For healthy
people, light drinking will not increase the risk of diabetes, and may even reduce the risk of
developing type 2 diabetes;64 however, heavy drinking does increase the risk of
developing diabetes and should be avoided.65 People with diabetes should limit
alcohol intake to two drinks per day. Total avoidance of alcohol in people with diabetes who
are not suffering from alcoholism,
liver disease (e.g., cirrhosis), gastritis, ulcers, and other conditions made worse by alcohol
might actually be counterproductive. In one report, older people with type 2 diabetes who
drank daily, but moderately, had a dramatically lower incidence of deaths from heart disease compared with nondrinkers.66
This outcome is not surprising since moderate alcohol intake is associated with protection
from heart disease in most other reports. This finding may be of particular importance because
heart disease is the leading killer of people with diabetes. In another study, nondrinkers had
a higher incidence of type 2 diabetes than did moderate drinkers.67
People with diabetes who smoke are at higher risk for kidney damage,68 heart
disease,69 and other diabetes-linked problems. Smokers are also more likely to
develop diabetes,70 so it's important for diabetic smokers to quit.
Although most healthcare professionals agree on the necessity of self-monitoring of blood
glucose (SMBG) by people with type 1 diabetes, disagreement exists within the medical
community regarding the efficacy and necessity of SMBG by people with type 2 diabetes. A
controlled clinical trial found that home glucose monitoring strips did not affect the
management of type 2 diabetes.71 Moreover, a review of available literature
concluded that the efficacy of SMBG in people with type 2 diabetes is questionable and should
be tested in a rigorous high-quality trial.72 Advocates of SMBG, such as the ADA,
have observed that SMBG by people with diabetes has revolutionized management of the disease,
enabling them to achieve and maintain specific goals.73 These observations are
well-supported in the medical literature.74 Detractors point out that
indiscriminate use of self-monitoring is of questionable value and adds enormously to
healthcare costs.75 The ADA acknowledges that accuracy of SMBG is instrument- and
technique-dependent. Errors in technique and inadequate use of control procedures have been
shown to lead to inaccurate test results.76 Nevertheless, it is likely that
self-monitoring of blood glucose, if used properly, can have a positive effect by increasing a
person's involvement in overall diabetes care.77 Pharmacists and healthcare
practitioners can teach people with diabetes certain skills that will enhance their ability to
properly self-manage blood glucose.
Vitamins that may be helpful
A variety of vitamins, minerals, amino acids, and other supplements may help with symptoms
and deficiencies associated with diabetes.
Multiple
Vitamin–Mineral Supplement
In a double-blind study, supplementation of middle-aged and elderly diabetics with a multiple
vitamin and mineral preparation for one year reduced the risk of infection by more than 80%,
compared with a placebo.78
Chromium
Medical reports dating back to 1853, as well as modern research, indicate that chromium-rich
brewer’s yeast (9 grams per day) can be
useful in treating type 2 diabetes.7980 In recent years, chromium has
been shown to improve glucose levels and related variables in people with glucose intolerance
and type 2, gestational, and steroid-induced diabetes.8182 Improved
glucose tolerance with lower or similar levels of insulin have been reported in more than ten
trials of chromium supplementation in people with varying degrees of glucose
intolerance.83 Chromium supplements improve glucose tolerance in people with type 2
diabetes,84 apparently by increasing sensitivity to insulin.85 Chromium improves the processing
of glucose in people with prediabetic glucose intolerance and in women with diabetes
associated with pregnancy.86
87 Chromium even helps healthy people,88 although one such report found
chromium useful only when accompanied by 100 mg of niacin per day.89 Chromium may also lower
levels of total cholesterol, LDL cholesterol,
and triglycerides (risk factors in heart disease).9091
A few trials have reported no beneficial effects from chromium
supplementation.929394 All of these trials used 200 mcg or
less of supplemental chromium, which is often not adequate for people with diabetes,
especially if it is in a form that is poorly absorbed. The typical amount of chromium used in
research trials is 200 mcg per day, although as much as 1,000 mcg per day has been
used.95 Many doctors recommend up to 1,000 mcg per day for people with
diabetes.96
Supplementation with chromium or brewer’s yeast could potentially enhance the effects
of drugs used for diabetes (e.g., insulin or other blood sugar-lowering agents) and possibly
lead to hypoglycemia. Therefore, people with
diabetes taking these medications should supplement with chromium or brewer’s yeast only
under the supervision of a doctor.
Magnesium
People with type 2 diabetes tend to have low magnesium levels.97 Double-blind
research indicates that supplementing with magnesium overcomes this problem.98
Magnesium supplementation has improved insulin production in elderly people with type 2
diabetes.99 However, one double-blind trial found no effect from 500 mg magnesium
per day in people with type 2 diabetes, although twice that amount led to some
improvement.100 Elders without diabetes can also produce more insulin as a result
of magnesium supplements, according to some,101 but not all, trials.102
However, in people with type 2 diabetes who nonetheless require insulin, Dutch researchers
have reported no improvement in blood sugar levels from magnesium
supplementation.103 The American Diabetes Association acknowledges strong
associations between magnesium deficiency and insulin resistance but has not said magnesium
deficiency is a risk factor104 Many doctors, however, recommend that people with
diabetes and normal kidney function supplement with 200 to 600 mg of magnesium per day.
Diabetes-induced damage to the eyes is more likely to occur in magnesium-deficient people
with type 1 diabetes.105 In magnesium-deficient pregnant women with type 1 diabetes, the lack of
magnesium may even account for the high rate of spontaneous abortion and birth defects associated with type 1
diabetes.106 The American Diabetes Association admits “strong
associations...between magnesium deficiency and insulin resistance” but will not say
magnesium deficiency is a risk factor.107 Many doctors, however, recommend that
people with diabetes and normal kidney function supplement with 200–600 mg of magnesium
per day.
Alpha lipoic
acid
Alpha lipoic acid is a powerful natural
antioxidant. Preliminary and double-blind trials have found that supplementing 600 to
1,200 mg of lipoic acid per day improves insulin sensitivity and the symptoms of diabetic
neuropathy.108109110111112
113114115 In a preliminary study, supplementing with 600 mg of
alpha lipoic acid per day for 18 months slowed the progression of kidney damage in patients
with type 2 diabetes.116
Evening primrose
oil
Supplementing with 4 grams of evening primrose oil per day for six months has been found in
double-blind research to improve nerve function and to relieve pain symptoms of diabetic
neuropathy.117
Glucomannan
Glucomannan is a water-soluble dietary fiber derived from konjac root (Amorphophallus
konjac)that delays stomach emptying, leading to a more gradual absorption of dietary
sugar. This effect can reduce the elevation of blood sugar levels that is typical after a
meal. 118 After-meal blood sugar levels are lower in people with diabetes given
glucomannan in their food, 119 and overall diabetic control is improved with
glucomannan-enriched diets, according to preliminary and controlled clinical trials.
120121122 One preliminary report suggested that glucomannan may
also be helpful in pregnancy-related diabetes. 123 For controlling blood sugar, 500
to 700 mg of glucomannan per 100 calories in the diet has been used successfully in controlled
research.
Vitamin
E
People with low blood levels of vitamin E are more likely to develop type 1 and type 2
diabetes.124125 Vitamin E supplementation has improved glucose
tolerance in people with type 2 diabetes in most,126127128
but not all,129 double-blind trials. Vitamin E has also improved glucose tolerance
in elderly people without diabetes.130131 Three months or more of at
least 900 IU of vitamin E per day may be required for benefits to become apparent.
In one of the few trials to find vitamin E supplementation ineffective for glucose
intolerance in people with type 2 diabetes, damage to nerves caused by the diabetes was
nonetheless partially reversed by supplementing with vitamin E for six months.132
Animal and preliminary human data indicate that vitamin E supplementation may protect against
diabetic retinopathy and
nephropathy,133134 serious complications of diabetes involving the eyes
and kidneys, respectively, though no long-term trials in humans have confirmed this
preliminary evidence.
Glycosylation is an important measurement of diabetes; it refers to how much sugar attaches
abnormally to proteins. Excessive glycosylation appears to be one of the causes of the organ
damage that occurs in diabetes. Vitamin E supplementation has reduced the amount of
glycosylation in many,135136137138
139 although not all,140141142 studies.
In one report, vitamin E was found to impair glucose tolerance in obese patients with diabetes.143 The reason
for the discrepancy between reports is not known.
Vitamin E appears to lower the risk of cerebral infarction, a type of stroke, in people with diabetes who smoke. A review of
a large Finnish study of smokers concluded that smokers with diabetes (or hypertension) can benefit from small amounts of
vitamin E (50 IU per day).144
Vitamin
C
As with vitamin E, vitamin C may reduce glycosylation.145 Vitamin C also lowers
sorbitol levels in people with diabetes.146 Sorbitol is a sugar that can accumulate
inside the cells and damage the eyes, nerves, and kidneys of people with diabetes. Vitamin C
may improve glucose tolerance in type 2 diabetes,147148 although not
every study confirms this benefit.149 Vitamin C supplementation (500 mg twice a day
for one year) has significantly reduced urinary protein loss in people with diabetes. Urinary
protein loss (also called proteinuria) is associated with poor prognosis in
diabetes.150 Many doctors suggest that people with diabetes supplement with 1 to 3
grams per day of vitamin C. Higher amounts could be problematic, however. In one person, 4.5
grams per day was reported to increase blood sugar levels.151
One study examined antioxidant supplement intake, including both vitamins E and C, and the
incidence of diabetic retinopathy (damage to
the eyes caused by diabetes).152 Surprisingly, people with extensive retinopathy
had a greater likelihood of having taken vitamin C and vitamin E supplements. The
outcome of this trial, however, does not fit with most other published data and might simply
reflect the fact that sicker people are more likely to take supplements in hopes of getting
better. For the present, most doctors remain relatively unconcerned about the outcome of this
isolated report.
B Vitamins
Many people with diabetes have low blood levels of vitamin B6.153154 Levels are
even lower in people with diabetes who also have nerve damage (neuropathy).155
Vitamin B6 supplementation has improved glucose tolerance in women with diabetes caused by
pregnancy.156157 Vitamin B6 supplementation is also effective for
glucose intolerance induced by birth control
pills.158 In a trial that included people with type 2 diabetes, 1,800 mg per
day of a special form of vitamin B6—pyridoxine alpha-ketoglutarate—improved
glucose tolerance dramatically.159 Standard vitamin B6 has helped in
some,160 but not all, trials.161
A controlled trial in Africa found that supplementing with both vitamin B1 (25 mg per day)
and vitamin B6 (50 mg per day) led to
significant improvement of symptoms of diabetic neuropathy after four weeks.162
However, since this was a trial conducted among people in a vitamin B1–deficient
developing country, these improvements might not occur in other people with diabetes. Another
trial found that combining vitamin B1 (in a special fat-soluble form) and vitamin B6 plus vitamin B12 in high but variable amounts led to
improvement in some aspects of diabetic neuropathy in 12 weeks.163 As a result,
some doctors recommend that people with diabetic neuropathy supplement with vitamin B1, though
the optimal level of intake remains unknown.
Biotin is a B vitamin needed to process
glucose. When people with type 2 diabetes were given 9 mg of biotin per day for two months,
their fasting glucose levels dropped dramatically.164 Biotin may also reduce pain from diabetic nerve damage.165
Some doctors try 9 to 16 mg of biotin per day for a few weeks to see if blood sugar levels
will fall.
Vitamin B12 is needed for normal
functioning of nerve cells. Vitamin B12 taken orally has reduced symptoms of nerve damage
caused by diabetes in 39% of people studied; when given both intravenously and orally,
two-thirds of people improved.166 In a preliminary trial, people with nerve damage
due to kidney disease or to diabetes plus kidney disease received intravenous injections of
500 mcg of methylcobalamin (the main form of vitamin B12 found in the blood) three times a day
for six months in addition to kidney dialysis. Nerve pain was significantly reduced and nerve
function significantly improved in those who received the injections.167 Oral
vitamin B12 up to 500 mcg three times per day is recommended by some practitioners.
The intake of large amounts of niacin (a
form of vitamin B3), such as 2 to 3 grams per day, may impair glucose tolerance and should be
used by people with diabetes only with medical supervision.168169
Smaller amounts (500 to 750 mg per day for one month followed by 250 mg per day) may help some
people with type 2 diabetes,170 though this research remains preliminary.
Coenzyme
Q10
Coenzyme Q10 (CoQ10) is needed for normal blood sugar metabolism. Animals with diabetes have
been reported to be CoQ10 deficient. People with type 2 diabetes have been found to have
significantly lower blood levels of CoQ10 compared with healthy people.171 In one
trial, blood sugar levels fell substantially in 31% of people with diabetes after they
supplemented with 120 mg per day of CoQ7, a substance similar to CoQ10.172 The
importance of CoQ10 supplementation for people with diabetes remains an unresolved issue,
though some doctors recommend approximately 50 mg per day as a way to protect against possible
effects associated with diabetes-induced depletion.
L-carnitine
L-carnitine is an amino acid needed to
properly utilize fat for energy. When people with diabetes were given DL-carnitine (0.5 mg per
2.2 pounds of body weight), high blood levels of fats—both cholesterol and triglycerides—dropped 25 to 39% in just ten days
in one trial.173
Acetyl-L-carnitine
In a double-blind study of people with diabetic neuropathy, supplementing with
acetyl-L-carnitine was significantly more effective than a placebo in improving subjective
symptoms of neuropathy and objective measures of nerve function.174 People who
received 1,000 mg of acetyl-L-carnitine three times per day tended to fare better than those
who received 500 mg three times per day.
Zinc
People with type 2 diabetes tend to be zinc deficient,175 but some evidence
indicates that zinc supplementation does not improve their ability to process
sugar.176 Nonetheless, many doctors recommend that people with type 2 diabetes
supplement with moderate amounts of zinc (15 to 25 mg per day) as a way to correct the
deficit.
Antioxidants
Because oxidation damage is believed to play a role in the development of diabetic
retinopathy, antioxidant nutrients might be protective. One doctor has administered a daily
regimen of 500 mcg selenium, 800 IU vitamin E, 10,000 IU vitamin A, and 1,000 mg vitamin C for several years to 20 people with diabetic
retinopathy. During that time, 19 of the 20 people showed either improvement or no progression
of their retinopathy.177 People who wish to supplement with more than 250 mcg of
selenium per day should consult a healthcare practitioner.
Vitamin
D
Vitamin D is needed to maintain adequate blood levels of insulin.178 Vitamin D
receptors have been found in the pancreas where insulin is made, and preliminary evidence
suggests that supplementation can improve some measures of blood sugar control in people with
type 2 diabetes.179180 Not enough is known about optimal amounts of
vitamin D for people with diabetes, and high amounts of vitamin D can be toxic; therefore,
people with diabetes considering vitamin D supplementation should talk with a doctor and have
their vitamin D status assessed.
Inositol
Inositol is needed for normal nerve function. Diabetes can cause a type of nerve damage known
as diabetic neuropathy. This condition has been reported in some, but not all, trials to
improve with inositol supplementation (500 mg taken twice per day).181
Taurine
Animal studies have shown that supplementing with taurine, an amino acid found in protein-rich
food, may affect insulin secretion and action, and may have potential in protecting the eyes
and nerves from diabetic complications.182 However, a double-blind trial found no
effect on insulin secretion or sensitivity when men with high risk for developing diabetes
were given 1.5 grams per day of taurine for eight weeks.183 In another double-blind
trial, taurine supplementation (2 grams per day for 12 months) failed to improve kidney
complications associated with type 2 diabetes.184
Fish
oil
Glucose tolerance improves in healthy people taking omega-3 fatty acid
supplements,185 and some studies have found that fish oil supplementation also
improves glucose tolerance,186 high
triglycerides,187 and
cholesterol levels in people with type 2 diabetes.188 And in one trial, people
with diabetic neuropathy and diabetic nephropathy experienced significant improvement when
given 600 mg three times per day of purified eicosapentaenoic acid (EPA)—one of the two
major omega-3 fatty acids found in fish oil supplements—for 48 weeks.189
However, other studies have found that type 2 diabetes worsens with fish oil
supplementation.190191192193 Until this issue
is resolved, people with diabetes should feel free to eat fish, but they should consult a
doctor before taking fish oil supplements.
Quercetin
Doctors have suggested that quercetin might help people with diabetes because of its ability
to reduce levels of sorbitol—a sugar that accumulates in nerve cells, kidney cells, and
cells within the eyes of people with diabetes—and has been linked to damage to those
organs.194 Clinical trials have yet to explore whether quercetin actually protects
people with diabetes from neuropathy, nephropathy, or retinopathy.
Vanadium
Vanadyl sulfate, a form of vanadium, may improve glucose control in people with type 2
diabetes.195196197 Over a six-week period, a small group of
people with type 2 diabetes were given 75 to 300 mg of vanadyl sulfate per day.198
Only in the groups receiving 150 mg or 300 mg was glucose metabolism improved, fasting blood
sugar decreased, and another marker for chronic high blood sugar reduced. At the 300 mg level,
total cholesterol decreased, although not without an accompanying reduction in the protective
HDL cholesterol. None of the amounts improved insulin sensitivity. Although there was no
evidence of toxicity after six weeks of vanadyl sulfate supplementation, gastrointestinal side
effects were experienced by some of the participants taking 150 mg per day and by all of the
participants taking 300 mg per day. The long-term safety of the large amounts of vanadium
needed to help people with type 2 diabetes (typically 100 mg per day) remains unknown. Many
doctors expect that amounts this high may prove to be unsafe in the long term.
Fructo-oligosaccharides
In a preliminary trial, supplementation with fructo-oligosaccharides (FOS) (8 grams per day
for two weeks) significantly lowered fasting blood-sugar levels and serum total-cholesterol
levels in people with type 2 diabetes.199 However, in another trial, supplementing
with FOS (15 grams per day) for 20 days had no effect on blood-glucose or lipid levels in
people with type 2 diabetes.200 In addition, some double-blind trials showed that
supplementing with FOS or galacto-oligosaccharides (GOS) for eight weeks had no effect on
blood-sugar levels, insulin secretion, or blood lipids in healthy people.201
202 Because of these conflicting results, more research is needed to determine the
effect of FOS on diabetes and lipid levels.
Manganese
People with diabetes may have low blood levels of manganese.203 Animal research
suggests that manganese deficiency can contribute to glucose intolerance and may be reversed
by supplementation.204 A young adult with insulin-dependent diabetes who received
oral manganese chloride (3 to 5 mg per day as manganese chloride) reportedly experienced a
significant fall in blood glucose, sometimes to dangerously low levels. In four other cases,
manganese supplementation had no effect on blood glucose levels.205 People with
diabetes wishing to supplement with manganese should do so only with a doctor’s
supervision.
Medium-chain
triglycerides
Based on the results of a short-term clinical trial that found that medium-chain triglycerides
(MCT) lower blood glucose levels,206 a group of researchers investigated the use of
MCT to treat people with type 2 diabetes mellitus. Supplementation with MCT for an average of
17.5% of their total calorie intake for 30 days failed to improve most measures of diabetic
control.207
Starch
blockers
Starch blockers are substances that inhibit amylase, the digestive enzyme required to break
down dietary starches for normal absorption. Controlled research has demonstrated that
concentrated starch blocker extracts, when given with a starchy meal, can reduce the usual
rise in blood sugar levels of both healthy people and diabetics.208209210211212 While this effect could be helpful in controlling
diabetes, no research has investigated the long-term effects of taking starch blockers for
this condition.
Are there any side effects or interactions?
Refer to the individual supplement for information about any side effects or interactions.
Herbs that may be helpful
Several herbs may help in managing symptoms associated with diabetes, including the control
of blood sugar levels.
Aloe
Animal research and preliminary controlled human trials have found that Aloe vera,
either alone or in combination with the oral hypoglycemic drug glibenclamide, effectively
lowers blood sugar in people with type 2 diabetes.213214215216 The typical amount used in this research was 1 tablespoon (15 ml) of aloe gel
per day.
Cayenne
Double-blind trials have shown that topical application of creams containing 0.025 to 0.075%
capsaicin (from cayenne [Capsicum frutescens]) can relieve symptoms of diabetic
neuropathy (numbness and tingling in the extremities caused by diabetes).217
218 Four or more applications per day may be required to relieve severe pain. This should be done only under a doctor’s
supervision.
Fenugreek
Fenugreek seeds are high in soluble fiber, which helps lower blood sugar by slowing down
carbohydrate digestion and absorption.219 Animal research suggests that fenugreek
may also contain a substance that stimulates insulin production and improves blood sugar
control.220221 In a controlled trial, incorporating 15 grams of
powdered fenugreek seed into a meal eaten by people with type 2 diabetes reduced the rise in
blood glucose following the meal.222 Another controlled trial found that taking 2.5
grams of fenugreek twice a day for three months reduced blood sugar levels in people with
mild, but not those with severe, type 2 diabetes.223 In a double-blind study, 1
gram per day of an extract of fenugreek seeds for two months improved some measures of blood
sugar control and insulin function in people with type 2 diabetes.224
Psyllium
Supplementing with psyllium has been shown to be a safe and well-tolerated way to improve
control of blood glucose and cholesterol. In a double-blind trial, men with type 2 diabetes
who took 5.1 grams of psyllium per day for eight weeks lowered their blood glucose levels by
11 to 19.2%, their total cholesterol by 8.9%, and their LDL (bad) cholesterol by 13%, compared
with a placebo.225
Asian
ginseng
Asian ginseng is commonly used in Traditional
Chinese Medicine to treat diabetes. It has been shown in test tube and animal studies to
enhance the release of insulin from the pancreas and to increase the number of insulin
receptors.226227 Animal research has also revealed a direct blood
sugar–lowering effect of ginseng.228 A double-blind trial found that 200 mg
of ginseng extract per day improved blood sugar control, as well as energy levels in people
with type 2 diabetes.229
American
ginseng
In a small preliminary trial, 3 grams of American ginseng was found to lower the rise in blood
sugar following the consumption of a high-glucose drink by people with type 2
diabetes.230 The study found no difference in blood sugar–lowering effect if
the herb was taken either 40 minutes before the drink or at the same time. A follow-up to this
study found that increasing the amount of American ginseng to either 6 or 9 grams did not
increase the effect on blood sugar following the high-glucose drink in people with type 2
diabetes.231 This study also found that American ginseng was equally effective in
controlling the rise in blood sugar whether it was given together with the drink or up to two
hours before.
Basil
Preliminary trials of holy basil (Ocimim
sanctum) leaves and hairy basil (Ocimum canum) seeds have shown that these herbs
may help people with type 2 diabetes control their blood sugar levels.232
233234 An uncontrolled study reported that 1,000 mg per day of holy basil
lowered blood sugar, LDL (“bad”) cholesterol, and triglycerides,235
while a controlled trial tested 2,500 mg per day and found similar changes in blood sugar, but
only minor effects on total blood cholesterol.236 The mechanism of action of holy
basil leaf is not understood and it is unknown whether common culinary sweet basil (Ocimum
basilicum) would have similar effects.
Gymnema
Gymnema may stimulate the pancreas to produce
insulin in people with type 2 diabetes. Gymnema also improves the ability of insulin to
lower blood sugar in people with both type 1 and type 2 diabetes. So far, no double-blind
trials have confirmed the efficacy of gymnema for people with any type of diabetes. However, a
preliminary study of type 2 diabetics reported that 400 mg per day of gymnema extract taken
for periods of 18 months or longer resulted in improvement, according to diabetes blood tests,
and allowed reduction of diabetic medications.237 In a controlled trial with type 1
(insulin-dependent) diabetics, a similar amount of gymnema extract reduced requirements for
insulin.238 Whether the extract used in these studies was standardized for active
constituents is unclear. Recently, a preliminary trial found improved blood sugar levels after
three months in a group of type 1 and type 2 diabetics who took 800 mg per day of an extract
standardized for 25% gymnemic acids.239 Gymnema is not a substitute for insulin,
but insulin amounts may need to be lowered while taking gymnema to avoid hypoglycemia.
Milk
thistle
In a double-blind trial, supplementation with silymarin (a component of milk thistle) in the
amount of 200 mg three times per day for four months significantly improved measures of blood
sugar control compared with a placebo.240
Bitter
melon
Whole, fried slices,241 water extracts,242 and juice of bitter melon may
improve blood-sugar control in people with type 2 diabetes,243 according to
preliminary trials. However, double-blind trials are needed to confirm this potential
benefit.
Cinnamon
Test tube studies have suggested that cinnamon may improve the glucose utilization. In a study
of people with type 2 diabetes, supplementing with cinnamon in the amount of 1, 3, or 6 grams
per day for 40 days was significantly more effective than a placebo at reducing blood glucose
levels.244 The reduction averaged 18 to 29% in the three treatments groups, and 1
gram per day was as effective as 3 and 6 grams per day. However, in a double-blind study,
supplementation with 1.5 g of cinnamon per day for six weeks was no more effective than a
placebo for reducing blood sugar levels.245
Crepe myrtle Lagerstroemia speciosa, commonly known as crepe myrtle, grows in various tropical
countries and Australia. In folk medicine it has been used to treat diabetes. In a preliminary
study of people with type 2 diabetes, supplementing with an extract from the leaves of
Lagerstroemia speciosa for two weeks resulted in a fall in blood-glucose levels averaging
20 to 30%.246 The amount used was 32 or 48 mg of a product standardized to contain
1% corosolic acid (a putative active ingredient). The larger amount was somewhat more effect
than the smaller amount. Although these results are promising, additional studies are needed
to demonstrate the long-term safety and efficacy of this herbal preparation.
Onion
Preliminary trials and at least one double-blind trial have shown that large amounts of onion can lower blood sugar levels in people with
diabetes.247248249 The mechanism of onion’s blood
sugar-lowering action is not precisely known, though there is evidence that constituents in
onions block the breakdown of insulin in the liver. This would lead to higher levels of
insulin in the body.250
Bilberry
Bilberry may lower the risk of some diabetic complications, such as diabetic cataracts and retinopathy. One preliminary trial found that
supplementation with a standardized extract of bilberry improved signs of retinal damage in
some people with diabetic retinopathy.251
Açaí
Açaí is reported to be a traditional
remedy for diabetes. Although oxidative stress may contribute to diabetes252 and
anthocyanins may improve insulin secretion,253 there is no published evidence that
açaí has any effect on diabetes.
Ginkgo Ginkgo biloba extract may prove useful for prevention and treatment of early-stage
diabetic neuropathy, though research is at best very preliminary in this area.254
Hibiscus
Hibiscus is a traditional remedy in India for diabetes; this treatment is supported by
preliminary studies from that country and by animal studies.255256
Hibiscus is usually taken as tea, such as 1 to 2 teaspoons (3 to 6 grams) of dried flower
infused in to 1 cup (250 ml) three times per day.
Mistletoe
Mistletoe extract has been shown to stimulate insulin release from pancreas
cells,257 and animal research found that it reduces symptoms of
diabetes.258 No research in humans has yet been published; however, given
mistletoe’s worldwide reputation as a traditional remedy for diabetes, clinical trials
are warranted to validate these promising preliminary findings. Traditionally, mistletoe is
prepared by soaking 2 to 4 teaspoons (5 to 12 grams) of chopped mistletoe in 2 cups (500 ml)
of water overnight. The mixture is drunk first thing in the morning and sweetened with honey
if desired. Another batch may be left to steep during the day and drunk at bedtime.
Olive
leaf
Olive leaf extracts have been used experimentally to lower elevated blood-sugar levels in
diabetic animals.259 These results have not been reproduced in human clinical
trials.
Reishi
Animal studies and some very preliminary trials in humans suggest reishi may have some
beneficial action in people with diabetes.260261
Are there any side effects or interactions?
Refer to the individual herb for information about any side effects or interactions.
Holistic approaches that may be helpful
Acupuncture may be helpful in the treatment
of diabetes, or complications associated with diabetes. Preliminary trials have suggested that
acupuncture can lower blood sugar and improve insulin production in people with type 2
diabetes,262263264265 but trials on long-term
effects have not been concluded. In a preliminary trial, 77% of people suffering from diabetic
neuropathy experienced significant reduction in
pain following up to six acupuncture treatments over a ten-week period. Many were also
able to reduce pain medications, but no long-term change in blood-sugar control was
observed.266 Bladder control problems, a complication of long-term diabetes,
responded to acupuncture treatment with a significant reduction in symptoms in both controlled
and uncontrolled trials.267268
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