Improve Metabolic Health with Quercetin

Metabolic disorders can result in rapid onset of chronic illnesses.

Dietary factors, sedentary lifestyle, and poor gut health are contributors to poor metabolic health.^1-3

Scientists have learned that quercetin, found in plant foods, can counter metabolic dysfunction.⁴

A clinical study in older adults with metabolic syndrome found that quercetin reduced cardiovascular risk factors.⁵

What is Metabolic Syndrome?

Metabolic syndrome is a cluster of conditions that includes any three of the following: ⁶

• Elevated blood pressure
• High blood sugar
• Large waist circumference
• Low HDL cholesterol
• High triglycerides

Individuals with metabolic syndrome are at increased risk of diabetes and its complications, cardiovascular disease, age-related disorders, and death.^6,7

Quercetin to the Rescue

Scientists have long been intrigued about why unprocessed, plant-based diets are protective against metabolic disease.

One nutrient, the flavonoid quercetin, is particularly prevalent in a wide range of fruits, vegetables, and medicinal plants. Hundreds of studies—in cell culture, animals, and humans—have documented the multiple properties of this nutrient.

Many of its effects in the body apply directly to metabolic health, reversing many of the changes present when metabolic health is not ideal.⁴

In a controlled clinical trial in older adults with metabolic syndrome, quercetin was shown to improve metabolic health, reduce cardiovascular risk factors, and decrease participants’ metabolic age.⁵

Better Blood Glucose Control

Metabolic disease is usually thought to be caused by insulin resistance and insufficient blood glucose control.

The hormone insulin helps cells to take up and process nutrients from the diet, including sugars. In most metabolic diseases, cells fail to respond to insulin appropriately; this is called insulin resistance.^8,9

The result of insulin resistance is high blood levels of glucose that contribute to chronic degenerative diseases that accompany aging. That is why individuals with diabetes or the metabolic syndrome have higher rates of most chronic diseases.²

After-meal glucose spikes are damaging for all individuals, and likely more so for diabetics. These blood sugar surges are contributors to cellular and vascular damage and raise the risk of cardiovascular disease and premature death.

Quercetin has been shown to improve glucose control as shown on the following page:

• Preclinical studies show quercetin helps activate cellular pathways—such as AMPK—that improve metabolism and reverse insulin resistance.^4,10,11
• A meta-analysis of randomized controlled trials revealed that quercetin supplementation for eight weeks or more, at a dosage of 500 mg or higher, reduced fasting blood glucose. That same dose also reduced excess insulin concentrations.¹²
• Remarkably, even one single dose of quercetin has been demonstrated to exert a beneficial clinical effect in a study in type II diabetics. In a randomized, placebo-controlled trial, 24 diabetics already being treated with medication were given 400 mg of quercetin before receiving a simple sugar. After the sugar dose, blood glucose was suppressed in those who received quercetin, compared to the placebo arm.¹³
• Another clinical trial found that long-term quercetin supplementation resulted in a significantly improved response (lower blood sugar spike) to an oral glucose tolerance test.⁵

Quercetin supplementation clearly resulted in improved glucose control and a healthier carbohydrate metabolism.

Improved Lipid Levels

Another prominent feature of metabolic disease is elevated levels of LDL cholesterol and triglycerides and reduced HDL cholesterol (the “good cholesterol”).² Like elevated blood glucose, these changes are contributors to cardiovascular disease.^1,2

Multiple human studies have shown the benefits of quercetin for lipid abnormalities.

In overweight and obese adults with early metabolic syndrome, 150 mg of quercetin daily reduced blood pressure and oxidized LDL cholesterol.¹⁴

In healthy men, 150 mg of quercetin daily for eight weeks decreased waist circumference, after-meal systolic blood pressure (top number), and after-meal triglyceride levels.¹⁵

In a placebo-controlled trial in 110 patients with metabolic syndrome, aged 60-74, 240 mg of quercetin daily for three months lowered total and LDL cholesterol.⁵

A randomized controlled trial found that daily supplementation with quercetin lowered total cholesterol, LDL cholesterol, and triglycerides, and raised HDL cholesterol. ¹⁶

Protection of the Gut and Liver

Animal research has shown that quercetin can protect the liver from abnormal accumulations of fats and can improve lipid metabolism.^17-21

Even in patients being treated for non-alcoholic fatty liver disease, quercetin supplementation has been found to improve liver health, reducing signs of liver damage and inflammation while improving lipid levels.²²

It may also improve the gut microbiome, the mix of bacteria that reside in the intestines. Quercetin may help shift the mix of these microorganisms into a healthier form. Such changes would be expected to reduce inflammation and “leaky gut” and to have the potential of improving the health of other organs as well, body wide.²³

Obesity and Metabolic Syndrome

Obesity adds to risks of metabolic disturbances. A prospective study assessing the mortality status of 6,678 healthy middle-aged men concluded that metabolic syndrome increased the risk of sudden death from heart attack by 68%.⁷

A trial of overweight and obese adults with early metabolic syndrome tendencies tested 150 mg of quercetin daily. This modest dose reduced blood pressure and lowered levels of oxidized LDL cholesterol.²⁴

Another clinical study found that the same dose of quercetin ( 150 mg/day) for eight weeks decreased waist circumference and after-meal systolic blood pressure, while also lowering after-meal triglyceride levels in a group of otherwise healthy men.¹⁵

Reduction in Inflammation & Oxidative Stress

Chronic inflammation and oxidative stress due to free radicals are major contributors to all chronic diseases, especially metabolic disease.

Quercetin provides potent activity against both issues. It reduces oxidative stress and promotes the expression of antioxidant enzymes so that the body can better protect itself.

At the same time, quercetin powerfully controls inflammation by modulating cell signaling pathways. Clinical and non-clinical studies have demonstrated that it decreases production of pro-inflammatory compounds and helps prevent chronic inflammation.^25-28

Increased dietary intake of flavonoids such as quercetin may reduce the risk of chronic illnesses.²⁹

Summary

Metabolic disease is increasingly common. Abnormalities of metabolism manifest in several different conditions including diabetes, obesity, lipid abnormalities, and non-alcoholic fatty liver disease.

The epidemic of these disorders is expected to increase and will contribute to rapid aging and most chronic diseases.

Quercetin, a flavonoid found in several different fruits and vegetables, has a profound effect on metabolic health.

Studies show that supplementation with quercetin has positive effects on many aspects of metabolism, including improved blood glucose control, trimmer physique, improved blood lipid levels and gut health, and protection of the liver.

If you have any questions on the scientific content of this article, please call a Life Extension Wellness Specialist at 1-866-864-3027.

References

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