Metabolic Syndrome
Anthocyanins
Taking anthocyanins may help people with metabolic syndrome achieve better blood glucose control and normalize triglyceride and cholesterol levels.Dose:
> 400 mg dailyAnthocyaninsAnthocyanins are pigments found in many berries, as well as in other fruits and vegetables. Findings from a clinical trial in healthy and metabolic syndrome-affected subjects suggest anthocyanin supplementation may improve metabolic function in part by reducing inflammation.10 A meta-analysis of 32 randomized controlled trials, with a total of 1,491 participants with metabolic syndrome or its components, found anthocyanins can improve glucose and lipid metabolism, and may be more effective at doses exceeding 400 mg per day.11Berberine
Clinical trials have shown berberine can benefit all aspects of metabolic syndrome.Dose:
500 mg three times dailyBerberineBerberine is an alkaloid found in several medicinal plants, such as goldenseal (Hydrastis canadensis), barberry (Berberis vulgaris), Oregon grape (Mahonia aquifolium), and goldthread (Coptis chinensis). Results from laboratory research and clinical trials indicate berberine may have a positive impact on metabolic disorders including obesity, high cholesterol and triglyceride levels, insulin resistance, high blood glucose levels and type 2 diabetes, and high blood pressure.12,13 Some evidence suggests berberine may help people with metabolic syndrome by stimulating healthy function of adipose (fat) tissue.14,15
One controlled trial included 80 participants with metabolic syndrome; specifically, all of the participants had high blood pressure, insulin resistance/type 2 diabetes, and high cholesterol and triglyceride levels. All participants were treated conventionally, and half also received berberine at a dose not specified in the published report. After one month, measures of blood glucose control, insulin sensitivity, lipid metabolism, and systemic inflammation had improved more in those given berberine.16 A double-blind, placebo-controlled trial with 24 participants affected by metabolic syndrome found 500 mg of berberine three times daily for three months led to decreased waist circumference, blood pressure, and triglyceride levels, and increased insulin sensitivity.17
Cinnamon
Cinnamon has been shown to improve all aspects of metabolic syndrome.Dose:
1 to 3 grams dailyCinnamonBecause cinnamon and cinnamon extracts have demonstrated benefits in people with insulin resistance and type 2 diabetes, it has potential benefits in people with metabolic syndrome.18,19 A placebo-controlled trial that included 116 participants with metabolic syndrome found 3 grams of cinnamon per day for 16 weeks improved blood glucose, triglyceride, and cholesterol levels, as well as waist circumference, blood pressure, and blood glucose control.20 In a randomized controlled trial, cinnamon reduced signs of metabolic disease in people with type 2 diabetes: after eight weeks, study participants receiving 3 grams of cinnamon per day had lower blood glucose levels, triglyceride levels, body weight, and body fat, and improved blood glucose control.21 Similarly, in a placebo-controlled trial with 140 participants with diabetes, taking 1 gram of cinnamon daily for three months improved glucose and lipid metabolism and was associated with body fat and weight loss, with stronger effects in those with more severe obesity.22 Placebo-controlled trials in people with type 2 diabetes show cinnamon can reduce high blood pressure in people with metabolic disease.23,24 Furthermore, a meta-analysis of controlled trials showed cinnamon can also reduce high blood pressure, with greatest efficacy when used at a dose of 2 grams per day or less for at least 12 weeks.25Glucomannan
Taking a glucomannan fiber supplement may improve metabolic syndrome.Dose:
3 to 10 grams dailyGlucomannanGlucomannan, a type of water-soluble dietary fiber from the root of the konjac plant, may reduce risk factors in people with metabolic syndrome. A double-blind trial found that 8–13 grams per day of glucomannan improved cholesterol levels and blood glucose control in people with metabolic syndrome.26 It is thought to work in part by acting as a prebiotic fiber, enhancing colonies of beneficial gut bacteria that participate in regulating metabolism.27 Even in patients with type 2 diabetes, 3 grams of glucomannan per day for four weeks improved blood glucose control and lipid metabolism compared to placebo.28Green Tea
Strong evidence indicates green tea and black tea extracts can help individuals with metabolic syndrome reduce body weight, lower blood glucose levels, and raise HDL-cholesterol levels.Dose:
600 to 900 mg of tea catechins dailyGreen TeaDrinking tea has been associated with lower risk of metabolic syndrome, and both green and black tea extracts, as well as the green tea catechin epigallocatechin gallate (EGCG), have demonstrated positive effects in people with metabolic syndrome.29,30 One meta-analysis of six randomized controlled trials involving people with obesity and metabolic syndrome concluded consuming a green tea catechin-rich beverage reduces abdominal fat accumulation and improves metabolic status.31 A large meta-analysis of studies pooled findings from 16 controlled trials with a combined total of 1,090 participants with obesity and metabolic syndrome. The results showed that, while the evidence for green tea extract is stronger than that for black, both green and black tea extracts help lower blood glucose levels, raise HDL (“good”)-cholesterol levels, and reduce body mass index, but have no impact on blood pressure, triglycerides, or other cholesterol levels.32 Most studies finding beneficial metabolic effects used 600–900 mg of tea catechins per day for at least 12 weeks. It is important to note liver toxicity has been associated with the use of very high doses of green tea extracts.30Guar Gum
Taking a guar gum fiber supplement may improve metabolic syndrome.Dose:
3 to 10 grams dailyGuar GumGuar gum, another fiber supplement with similar properties to glucomannan, may also have metabolic benefits. A controlled trial in which subjects with type 2 diabetes and metabolic syndrome were given 10 grams per day of guar gum or placebo found those given guar gum had improved blood glucose control and reduced waist circumference after six weeks.33 Healthy men given the same dose of guar gum for six weeks were also reported to have experienced improvements in aspects of metabolic syndrome, including blood pressure and glucose, cholesterol, and triglyceride levels.34 Another preliminary trial noted taking 4 grams of guar flour twice daily reduced insulin resistance, decreased total and LDL-cholesterol levels, and increased HDL-cholesterol levels in men with type 2 diabetes.35Açaí
Preliminary evidence suggests acai berry may improve metabolic health.Dose:
200 grams of berry pulp dailyAçaíAçaí berries are high in polyphenols and therefore have a strong antioxidant action.36 In a pilot study, supplementing with 100 grams per day of açaí berry pulp for 30 days was found to lower blood glucose, insulin, and total and LDL-cholesterol levels in ten overweight adults with metabolic disease.37 However, in a placebo-controlled trial with 37 participants with metabolic syndrome, treatment with 325 mL of an açaí berry beverage (providing 370 mg of gallic acid) twice daily did not improve markers of glucose and lipid metabolism.38Chromium
Supplementing with chromium may be beneficial in people with type 2 diabetes and metabolic syndrome.Dose:
200 to 500 mcg daily, or more under doctor supervisionChromiumChromium is a mineral needed in trace amounts by the body. It has been widely studied for its potential benefits in people with insulin resistance and type 2 diabetes.39 A 23-year observational study found those with poorer baseline chromium status were more likely to develop metabolic syndrome than those with better chromium status.40 However, clinical trials examining the effects of chromium supplementation in people with metabolic syndrome have been mixed.
In one placebo-controlled trial with 70 subjects affected by metabolic syndrome, those receiving 300 micrograms of chromium (in the form of chromium-enriched yeast) per day had no changes in measures of glucose and lipid metabolism but had a decrease in resting heart rate.41 While high heart rate is not typically considered part of metabolic syndrome, it is linked to heart disease. In a placebo-controlled trial that enrolled 59 subjects diagnosed with high glucose levels, insulin resistance, or metabolic syndrome, taking either 500 micrograms or 1,000 micrograms of chromium (as chromium picolinate) daily for six months did not change any of the measured metabolic parameters.42 Chromium picolinate, at a dose of 1,000 micrograms per day, was also ineffective for improving metabolic markers in a placebo-controlled trial with 63 participants with obesity and metabolic syndrome.43 Nevertheless, a meta-analysis of 28 randomized controlled trials in people with type 2 diabetes concluded chromium not only improves markers of glucose regulation and insulin sensitivity, but also decreases triglyceride levels and increases HDL-cholesterol levels.44 The evidence therefore indicates chromium may specifically benefit those with metabolic syndrome co-occurring with type 2 diabetes.
Coenzyme Q10
A small body of clinical evidence suggests coenzyme Q10 may improve insulin sensitivity, glucose and lipid metabolism, and blood pressure in those with metabolic syndrome.Dose:
30 to 200 mg dailyCoenzyme Q10Coenzyme Q10 (CoQ10) has well known cardiovascular benefits.45 In people with metabolic syndrome, 100 mg of CoQ10 per day for eight weeks improved markers of insulin resistance, but had no impact on glucose, lipid, and inflammatory marker levels compared to placebo.46 A controlled trial that included 104 participants with metabolic syndrome compared the effects of a dietary intervention alone to diet plus 30 mg of CoQ10 and red yeast rice providing 10 mg of monacolin K (a cholesterol-lowering compound) per day. After two months, those taking the supplements had greater improvements in blood pressure, cholesterol levels, and glucose levels.47 Although CoQ10 has been reported to lower blood pressure in clinical trials in uncomplicated hypertensive subjects, a placebo-controlled trial in 30 patients with high blood pressure and metabolic syndrome found 200 mg of CoQ10 twice daily did not lower blood pressure after 12 weeks of treatment.45,49 CoQ10 may be helpful in treating metabolic syndrome associated with polycystic ovary syndrome: in one trial, 100 mg of CoQ10 per day for 12 weeks was more effective than placebo for improving glucose and lipid metabolism.50L-Carnitine
L-carnitine supplementation may reduce cardiovascular risk by improving metabolic parameters such as body weight, blood glucose control, insulin sensitivity, and lipid levels.Dose:
2 to 3 grams dailyL-CarnitineThe amino acid L-carnitine has been shown in clinical trials and meta-analyses to improve blood glucose control, insulin sensitivity, weight loss, and lipid metabolism, indicating its potential usefulness in treating metabolic syndrome and reducing cardiovascular risk.50,51 In one placebo-controlled trial, women with obesity and type 2 diabetes participated in a low-calorie diet program and received 2 grams of L-carnitine per day or placebo for about eight weeks. At the end of the trial, those receiving L-carnitine had greater improvements in blood glucose control, insulin sensitivity, cholesterol and triglyceride levels.52 In an uncontrolled trial, taking 3 grams of L-carnitine daily for three months led to decreased insulin resistance, LDL-cholesterol levels, and body-mass index (BMI), and increased HDL-cholesterol levels in 80 women with polycystic ovary syndrome, a condition associated with metabolic syndrome.53Magnesium
People with metabolic syndrome often have low magnesium status and benefit from magnesium supplementation.Dose:
300 mg dailyMagnesiumLow magnesium levels have been associated with increased risk of metabolic syndrome, as well as type 2 diabetes and cardiovascular disease, in multiple observational studies.54 A review of randomized controlled trials investigating the use of magnesium supplements in people with components of metabolic syndrome concluded magnesium has metabolic benefits in individuals with low magnesium levels.55 In one placebo-controlled trial that included 198 participants with metabolic syndrome and low magnesium status, taking 382 mg of elemental magnesium daily for 16 weeks reduced blood pressure, blood glucose levels, and triglyceride levels.56 However, 300 mg of magnesium along with 600 micrograms of chromium and 36 mg of zinc daily for 24 weeks did not impact aspects of metabolic syndrome in a placebo-controlled trial that included people with metabolic syndrome whose baseline magnesium status was not measured.57Myoinositol
Myoinositol, alone or in combination with d-chiro-inositol, may improve some aspects of metabolic syndrome in women with polycystic ovary syndrome.Dose:
1.1 to 4 grams daily; in combination supplements, the ratio of myoinositol to d-chiro-inositol is generally 40:1MyoinositolMyoinositol is best known for its therapeutic effects in women with polycystic ovary syndrome (PCOS). Myoinositol alone and in combination with another inositol isomer, d-chiro-inositol, has been reported to improve not only the hormonal aspects of PCOS but also some of the metabolic disturbances associated with the condition, including insulin resistance, high blood pressure, obesity, and lipid levels.58,59,60 One controlled trial found myoinositol was more effective than metformin (a medication frequently used to treat type 2 diabetes) for improving blood glucose control and triglyceride levels in women with PCOS after 12 weeks of treatment, but a similar trial did not note any metabolic advantages of myoinositol over metformin.61,62Omega-3 Fatty Acids
Fish oil and its omega-3 fatty acids have positive metabolic effects and are especially effective for lowering high triglyceride levels in people with metabolic syndrome.Dose:
1 to 2 grams of fish oil, or ~300 mg of combined EPA plus DHA, dailyOmega-3 Fatty AcidsPolyunsaturated omega-3 fatty acids from fish, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have anti-inflammatory properties that benefit metabolic and cardiovascular health.63,64 A meta-analysis of results from 27 studies found a relationship between higher blood levels of omega-3 fats and lower risk of metabolic syndrome.65
Other reviews of the research indicate omega-3 fatty acid supplementation can improve insulin sensitivity and blood vessel function in people with metabolic disorders.66,67 A controlled trial with 89 participants with metabolic syndrome found those who received 1 gram of fish oil, providing 180 mg of EPA and 120 mg of DHA, daily had improvement in metabolic parameters at the end of six months; specifically, reductions in body weight, blood pressure, LDL- and total-cholesterol levels, and triglyceride levels were noted.68 However, a twelve-week placebo-controlled trial with 417 subjects with metabolic syndrome found supplementing with 1.2 grams of polyunsaturated omega-3 fatty acids daily reduced triglyceride levels but had no impact on insulin sensitivity, blood pressure, cholesterol levels, or levels of inflammatory markers.69 Likewise, in a twelve-week trial involving men with metabolic syndrome, a reduced-calorie diet was found to improve metabolic signs, but adding a fish oil supplement provided no additional benefit except triglyceride lowering.70 A meta-analysis of five controlled trials in which overweight subjects with metabolic syndrome were treated with omega-3 fatty acids plus vitamin E found this supplement regime lowered triglyceride and LDL-cholesterol levels but otherwise did not alter metabolic parameters.71
Probiotics
Early research indicates probiotics have likely, though small, benefits on metabolic and cardiovascular health.Dose:
= 6.5 billion colony forming units (CFUs) dailyProbioticsThere is increasing awareness of the importance of gut bacteria in regulating metabolism and inflammatory immune function, and growing evidence indicates a role for probiotics, as well as prebiotics (fibers that enhance growth of beneficial bacteria) and synbiotics (combinations of pro- and prebiotics) in preventing and treating metabolic syndrome.72
One placebo-controlled trial compared the effects of a multi-strain probiotic supplement and an inulin-based synbiotic supplement to placebo in 120 participants with pre-diabetes. Both the probiotic and synbiotic supplements reduced the prevalence of metabolic syndrome more effectively than placebo.73 A meta-analysis was performed using data from nine randomized controlled trials investigating the use of probiotics in subjects with metabolic syndrome. The trials used different species of lactobacilli and bifidobacteria, at doses ≥ 6.5 billion colony forming units (CFUs), and lasted three to 12 weeks. Five of the trials reported small but statistically significant positive findings with regard to metabolic syndrome parameters such as body-mass index (BMI), blood glucose levels, and lipid metabolism.74 In addition, certain probiotic strains appear to improve gut microbiome composition and reduce blood levels of inflammatory markers in people with metabolic syndrome.75,76 More research is needed to identify specific strains, optimal doses, and duration of treatment needed for probiotics to improve metabolic health.
Vitamin D
Vitamin D deficiency increases the risk of metabolic disorders.Dose:
3 to 4,000 IU of vitamin D3 dailyVitamin DVitamin D has multiple actions that affect metabolic syndrome. It has been shown to lower blood glucose levels, reduce insulin resistance, regulate blood pressure, promote body weight management, improve fat tissue function, reduce inflammation, and normalize triglyceride and cholesterol levels.77 A number of studies have linked vitamin D deficiency to increased risks of insulin resistance, type 2 diabetes, and metabolic syndrome.78,79 Supplementation appears to be helpful in those with metabolic syndrome who have poor vitamin D status.80 Until more is known about vitamin D and metabolic syndrome, it is important to maintain sufficient vitamin D levels.Calcium
One study found that supplementing with calcium improved insulin sensitivity in people with hypertension.Dose:
Refer to label instructionsCalciumCaution: Calcium supplements should be avoided by prostate cancer patients.
One double blind trial found that 1,500 mg per day of calcium improved insulin sensitivity in people with hypertension.81 No research on the effects of calcium in people with metabolic syndrome has been done.
Vitamin E
Vitamin E supplements, particularly tocotrienols, have been found to be beneficial in treating the conditions that make up metabolic syndrome.Dose:
Refer to label instructionsVitamin ETwo clinical trials have examined the effects of vitamin E in subjects with metabolic syndrome. In the first trial, 80 participants received either 800 mg of alpha-tocopherol, 800 mg of gamma-tocopherol, 800 mg of each alpha- and gamma-tocopherol, or placebo daily; after six weeks, those receiving both forms of vitamin E had reductions in markers of oxidative stress, nitrogen-related stress, and inflammation, suggesting vitamin E may reduce tissue damage associated with metabolic syndrome.82 In the second trial, which included 57 participants, taking 400 mg per day of mixed tocotrienols (other forms of vitamin E) for 16 weeks reduced inflammatory marker levels and improved lipid profiles.83 In addition, vitamin E supplements, particularly tocotrienols, have been found to be beneficial in treating the conditions that make up metabolic syndrome, including obesity, high blood pressure, high glucose levels, and abnormal lipid profiles.84Zinc
Zinc is important for metabolic health, but there are risks associated with both too little and too much zinc.Dose:
15 to 50 mg dailyZincStudies examining the relationship between zinc status and metabolic syndrome have yielded mixed findings.85 A study based on data from 1,088 participants in the National Health and Nutrition Examination Study (NHANES) from 2011–2014 found a correlation between high zinc levels and increased risk of metabolic syndrome.86 However, according to a meta-analysis of 20 controlled trials, zinc supplementation appears to have metabolic benefits such as improving blood glucose control and triglyceride and cholesterol levels.87 Another research review noted zinc supplements have a positive impact on blood glucose control in those with type 2 diabetes who have zinc deficiency.85 Taken together, the research suggests the importance of avoiding zinc deficiency and excess for preventing cardiovascular disease and type 2 diabetes.