High Blood Sugar and Insulin Resistance

What approaches can help you manage high blood sugar and insulin resistance?

Conventionalthe medical care offered by conventionally trained physicians and most hospitals; examples are insulin and metformin, self-carelifestyle actions and behaviors that may impact cancer outcomes; examples include eating health-promoting foods, limiting alcohol, increasing physical activity, and managing stress, and complementaryin cancer care, complementary care involves the use of therapies intended to enhance or add to standard conventional treatments; examples include supplements, mind-body approaches such as yoga or psychosocial therapy, and acupuncture approaches are all available to help you control high blood sugar or correct insulin resistance. These almost always require monitoring and guidance from a health professional.

Top practices and therapies for managing high blood sugar and insulin resistance

Therapies and practices we have reviewed

Further therapies

Therapies recommended in clinical practice guidelines but that we haven’t yet reviewed; see guidelines ›

Other therapies

Several other therapies have some evidence of benefit for managing high blood sugar and insulin resistance. The benefit may be meaningful or even substantial, but our reviews show the evidence so far is preliminary. These are described below.

Conventional approaches

Many conventional approaches are available to control high blood sugar and diabetes. Your medical team should be able to help you find the best approach for your situation.

Self-care practices and complementary therapies

Practices or therapies with good or modest evidence of benefit

Strong evidenceconsistent, significant effects in several large (or at least one very large) well designed clinical studies or at least two meta-analyses of clinical studies of moderate or better quality (or one large meta-analysis) finding similar results (this is the CancerChoices definition; other researchers and studies may define this differently) indicates confidence that the practice or therapy has an effect as noted. Good evidencesignificant effects in one large or several mid-sized and well-designed clinical studies (randomized controlled trials (RCTs) with an appropriate placebo or other strong comparison control or observational studies that control for confounds) (this is the CancerChoices definition; other researchers and studies may define this differently) indicates that the practice or therapy is linked to the outcomes described with reasonable certainty. Modest evidencesignificant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observational studies), or several small studies aggregated into a meta-analysis (this is the CancerChoices definition; other researchers and studies may define this differently) means the practice or therapy may be linked to the outcomes described, but with a lower degree of certainty.

The evidence for these effects is described in the reviews available through the image links. A practice or therapy may show a stronger effect or have more evidence in some situations than in others.

Lower insulin resistance among people with type 2 diabetes eating a diet high in inositol hexaphosphate (IP-6, abundant in cereals, legumes, and nuts) (preliminary evidence)

Lower markers of insulin resistance or metabolic syndrome among people eating foods rich in carotenoids (carrots, squash, mango, cantaloupe, sweet potatoes and tomatoes) and especially lycopene (tomatoes, guava, watermelon, papaya, red oranges, and pink grapefruit), but not after only 4 weeks (preliminary evidence)

Lower markers of blood sugar and insulin resistance among a general population drinking green tea, but not among people with prediabetes or type 2 diabetes (modest evidence)

Higher risk of high blood sugar among people eating at night (preliminary evidence)

Fasting or calorie restriction: modest and preliminary evidence

Better markers of metabolism during radiation therapy among women with breast cancer following a ketogenic diet (preliminary evidence)

Not specific to cancer:

• Better blood sugar and insulin levels among people with diabetes following a ketogenic diet (strong evidence)

Mediterranean diet: mixed evidence

Lower blood glucose after a meal but not while fasting among people with blood cancers without diabetes or prediabetes at baseline treated with metformin (preliminary evidence)

Lower levels of blood sugar among nondiabetic people with breast or endometrial cancer treated with metformin (good evidence)

Lower insulin levels among nondiabetic or mixed groups of people with breast or endometrial cancer treated with metformin (preliminary evidence)

Lower insulin levels among nondiabetic people with colorectal cancer treated with metformin (preliminary evidence)

Insufficient (conflicting) evidence of an effect on insulin resistance among nondiabetic people with breast, endometrial, or ovarian cancer treated with metformin

No evidence of an effect on a marker of glycemic control among men with normal glycemia and locally advanced prostate cancer treated with metformin in a small study

Not specific to cancer:

• Lower levels of insulin or insulin resistance among people without cancer or diabetes treated with metformin (preliminary evidence)
• Lower levels of insulin, insulin resistance, and/or blood sugar among overweight or obese people or with impaired glucose tolerance or insulin resistance treated with metformin (preliminary evidence)

Not specific to cancer:

• Lower fasting blood glucose and insulin levels and a weak trend toward lower blood sugar among people with type 1 or 2 diabetes or prediabetes treated with probiotic, prebiotic, or synbiotic supplementation (good evidence)
• Lower blood sugar and insulin resistance among adults, most of whom are diabetic or prediabetic, treated with probiotics (modest evidence)
• Lower markers of high blood sugar and insulin levels, but no evidence of an effect on peripheral and adipose tissue insulin sensitivity, among adults treated with dietary prebiotics (not specific to cancer) (good evidence)
• Insufficient (conflicting) evidence of an effect on fasting blood sugar, insulin resistance, or insulin among adults with metabolic syndrome or metabolic disorders treated with probiotics or synbiotics

Quercetin: mixed evidence

Resveratrol: mixed evidence

• Lower insulin resistance and higher insulin sensitivity among people treated with vitamin D (modest evidence)
• Slightly lower risk of type 2 diabetes among women with the highest vitamin D intake from supplements (modest evidence)
• Higher insulin sensitivity and better blood glucose levels among people at risk for type 2 diabetes with higher vitamin D 25(OH)D levels (preliminary evidence)
• Lower vitamin D 25(OH)D levels among people with diabetes (preliminary evidence)
• Lower insulin resistance (HOMA) and better insulin sensitivity among people with diabetes or insulin resistance treated with vitamin D₃ (preliminary evidence)
• Lower insulin levels among women with polycystic ovary syndrome taking vitamin D supplements, but only when used in combination with calcium, vitamin K, zinc, or magnesium (weak evidence)
• Weak (conflicting) evidence of an effect on glycemic control (HbA1c), fasting blood glucose, insulin levels, and other measures of blood glucose and insulin balance among people with diabetes or insulin resistance

Vitamin D and calcium together: modest evidence

Not specific to cancer:

• Better blood sugar and insulin balance among people treated with both vitamin D and calcium (modest evidence)

Practices and therapies with preliminary or weak evidence of benefit for high blood sugar and insulin resistance

Preliminary evidencesignificant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect (this is the CancerChoices definition; other researchers and studies may define this differently) means the practice or therapy may be linked to the outcomes described, although substantial uncertainty remains. Weak evidenceone or more case studies, supported by animal evidence OR small treatment effects of limited clinical significance OR studies with no controls OR weak trends of effects (this is the CancerChoices definition; other researchers and studies may define this differently) may mean that the effects are small or that a high degree of uncertainty remains about the links between the practice or therapy and the outcomes described.

Therapies with no evidence of benefit for managing high blood sugar and insulin resistance

Reishi mushroom ›

Not specific to cancer:

• No evidence of a clinical effect on blood sugar or insulin resistance among people with type 2 diabetes treated with reishi mushrooms in a combined analysis of 3 small studies

Vitamin D › and whey protein together

Not specific to cancer:

• No evidence of an effect on markers of blood glucose and insulin resistance during participation in progressive resistance training among adults aged 50–75 years with overweight or obesity and with type 2 diabetes treated with whey protein and vitamin D₃ in one trial

Further therapies reported to have benefit for managing high blood sugar and insulin resistance

Those in bold are evaluated favorably in a clinical practice guideline for people with diabetes; see guidelines ›

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