Polyphenol-Rich Clove Extract Significantly Lowers After-Meal Blood Sugar By 21.5% In Healthy People And By 27.5% in Prediabetics

As a result of the human body ability to metabolize blood sugar breaking down, it sets off a cascade of harmful events that accelerates systemic aging. Even “high normal” blood sugar raises heart disease and stroke risk.^1-3 This loss of glucose control motivated scientists to evaluate whether an extract from cloves can lower elevated blood sugar (glucose).



In a new study, a standardized clove extract was tested on healthy people and those with prediabetes. The study results found lower after-meal blood sugar in healthy adults and prediabetics supplemented with polyphenol-rich clove extract.⁴
In the prediabetic part of the study, fasting glucose levels were also lowered in the clove-supplemented participants.

These new findings indicate that a standardized clove extract can benefit aging individuals who have less-than-optimal glucose control. This is especially important for prediabetics, who often suffer high after-meal glucose for years before the onset of type II diabetes or diabetic complications.



About 25% of Americans over 65 have type II diabetes, and about half of older Americans have prediabetes.^5,6
Typically, prediabetics may have “normal” fasting blood sugar levels, but often can’t properly handle glucose after a meal. Unless they make substantial changes to their diet and lifestyle, up to 30% of prediabetics will go on to develop type II diabetes in only three to five years.

Even if progression to full-blown diabetes does not occur, prediabetes increases the risk for heart disease and stroke.^7,8 Younger adults (aged 25-44) are now more than twice as likely to have diabetes and to be overweight than they were 30 years ago.^4,9

Numerous studies have shown that polyphenols, health-promoting nutrients found in plants, lower the risk of multiple diseases.^4,10-12 Diets low in polyphenols are strongly associated with increased risk of type II diabetes.^13-15 These findings are driving the search for naturally occurring polyphenols  that can lower blood sugar and help prevent type II diabetes and metabolic syndrome.

First Human Study on Cloves



Cloves are dried flower buds of the Syzygium aromaticum tree, which have been used as a spice for centuries or more.
One such particularly valuable clove extract contains a minimum of 30% total polyphenols, including gallic, chlorogenic, and ellagic acids, catechin, quercetin, and eugenol, all of which have health benefits.^16-18

In past studies, this clove extract demonstrated benefits in the liver, a key area of the body (along with fat and muscle) involved in insulin resistance. (Insulin resistance is an underlying abnormality that leads to prediabetes and diabetes.^4,18,19) These findings led scientists to hypothesize that polyphenol-rich clove extract is likely to have benefits for glucose metabolism in adult humans.

In a paper published in May 2019 in the journal BMC Complementary and Alternative Medicine, researchers demonstrated blood-sugar-reducing effects of a polyphenol-rich clove extract in healthy and prediabetic people.⁴

Fasting blood sugar levels have traditionally been used to identify those with, or at risk for, type II diabetes. But after-meal blood sugar (glucose) levels are also an important indicator of disease risk.^4,20 Studies show that after-meal blood sugar elevations are closely associated with cardiovascular disease and death.^21-23 In older diabetics, large swings in post-meal glucose also appear to contribute to impaired cognitive function.²⁴ An intervention that can delay or prevent elevated after-meal glucose is likely to help prevent blood sugar disturbances and metabolic syndrome.⁴

Medical researchers in the Department of Biochemistry at St. Thomas College in India evaluated before and after meal glucose levels in response to a polyphenolic clove extract supplement.⁴


Two groups of people were studied for 30 days. Group I had normal after-meal glucose. 

The researchers enrolled 13 healthy volunteers (aged 25-35), dividing them into two groups based on their initial pre-meal glucose levels. Group I had fasting glucose levels at or below 100 mg/dL (“normal”), and Group II had prediabetic levels of 101-125 mg/dL.⁴

On the first day, individuals ate a standard lunch immediately after the blood draw, and then right after lunch, all were given a 250 mg capsule of clove extract. After two hours, a post-meal glucose measurement was taken. This pattern was repeated daily for 30 days, with pre- and post-meal glucose measurements taken on days 12, 24, and 30.


Group II had high after-meal glucose. Daily intake of 250 mg of clove extract reduced after-meal
glucose levels by 21.5% in Group I and by 27.2% in Group II.


The study results found that in those with normal fasting glucose, clove supplementation had no impact on fasting glucose (before-meal) sugar levels.

Howver in the prediabetic group, clove extract caused significant reductions in pre-meal (fasting) glucose on days 24 and 30. This suggests that clove extract could help maintain normal blood sugar levels throughout the day in people with prediabetes those at highest risk for cardiovascular events and for developing type II diabetes.⁴

In both study groups, clove extract significantly lowered after-meal blood sugar levels. The average reduction in post-meal sugar levels over the 30-day study was 21.5% (from 125.4 mg/dL to 98.4 mg/dL) in the healthy group,
and 27.2% (from 148.3 mg/dL to 108 mg/dL) in the prediabetes group.⁴

These research results are impressive for several reasons. Unless one severely restricts the type and amount of food/drink ingested, there is an after-meal spike in blood glucose that silently inflicts cellular damage.

In those with higher after-meal glucose surges, the damage translates into increased risks of disorders associated with prediabetes. This includes micro-vascular complications such as neuropathy (burning feet), retinopathy (vision loss), and kidney impairment.

Prediabetic glucose surges also increase macro-vascular damage that results in coronary and cerebral artery disorders that cause heart attack and ischemic stroke.

Scientists added polyphenol-rich clove extract to cell cultures in a lab to study cell-level effects of the supplement.⁴

Clove extract was found to work through three different mechanisms as follows:⁴

• Enhanced glucose uptake into muscle cells by up to 63%, providing them with metabolic fuel and removing sugar from circulation.
• Inhibition of glucose production in liver cells, an important site where excess sugar is released (gluconeogenesis).
• Inhibition of two digestive enzymes (alpha-glucosidase and alpha-amylase) from releasing glucose from compounds such as sucrose (table sugar) and starch.

These study  findings reveal how this clove extract can:

• Protect against after-meal blood sugar spikes in normal and prediabetic people,
• Decrease fasting glucose in prediabetics, and
• Increase glucose consumption by muscle cells.

No currently available drug can accomplish this.

Researchers  have discovered that extracts of cloves have immediate and lasting impacts on blood sugar.



They slow glucose uptake from the intestine, reduce new glucose production in the liver, and boost glucose consumption by muscle cells all actions that help lower blood sugar.

In a new 2019 published study, 250 mg of a polyphenol-rich clove extract, taken daily after lunch, significantly reduced after-meal glucose spikes in healthy and prediabetic people. After-meal glucose spikes are closely associated with cardiovascular disease.

The clove extract also lowered pre-meal sugar levels in prediabetics, protecting them from chronic blood sugar elevations that can lead to type II diabetes.

But clove extracts didn’t lower pre-meal glucose in subjects with normal sugar levels, avoiding dangerous drops associated with some anti-diabetes medications.

Taking a daily 250 mg clove extract before a meal with the most starches or sugars has the potential to help maintain healthy glucose metabolism.

Thailand Medical News warns that individuals currently receiving medications to control blood sugar should consult their doctors before adding ingredients like clove extract to their diets and should closely monitor their blood sugar levels.


References

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