Life Extension Magazine®

Issue: Oct 2019

Clove Extract Lowers Blood Sugar

A study published in 2019 demonstrated that polyphenolrich clove extract significantly lowers after-meal blood sugar by 21.5% in healthy people and by 27.2% in prediabetics.

By Linda Carrington

When our ability to metabolize blood sugar breaks 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 pilot 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 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.

Diabetes Rates Skyrocket

glucose monitor

Roughly 25% of Americans over 65 have type II diabetes, and about half of older Americans have prediabetes.5,6

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

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.

 

Clove Extract Reduces After-Meal Blood Glucose in Humans

Group I chart - random glucose under 100 mg/dL
Group II chart - random glucose over 100 mg/dL

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

New 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 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

What the Study Showed

clover on a wooden spoon

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

For these reasons, Life Extension® scientists collaborated with scientific colleagues in the Department of Biochemistry at St. Thomas College in India and Akay to evaluate before- and after-meal glucose levels in response to a polyphenolic clove extract supplement.4

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 day one, 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.

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

But 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 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.

 
Maqui berries

Maqui Berry Provides Additional Support for Glucose Control

In looking for plant-based solutions to reducing the risks of high blood sugar, researchers have also identified additional benefits of the maqui berry.

Maqui-berry extract has been shown to lower after-meal rise in both glucose and insulin.

Standardized extracts of maqui berries can deliver healthy polyphenolic compounds known as delphinidins.

Delphinidins stimulate a peptide that lowers postprandial (after-meal) blood glucose and can have a moderating influence on insulin spikes.25

Maqui berry extract has also been shown to slow the rise of after-meal insulin levels.26

In a separate study, standardized maqui berry extract showed promise in reducing hemoglobin A1c (HbA1c). Hemoglobin A1c levels declined at 60 days, and by 90 days, this marker of long-term glucose control (HbA1c) was down by 0.3% from 5.65% to 5.35%.27

How Cloves Work

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 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.

 

A Word of Caution for Those Using Blood Glucose Lowering Drugs

The findings presented in this article should be of interest to anyone concerned about blood sugar levels.

Life Extension believes that an optimal fasting blood glucose should be less than 86 mg/dL.

The risk of hypoglycemia (low blood sugar) increases with intensive glycemic control.

Individuals currently receiving medications to control blood sugar should consult their doctor before adding ingredients like clove extract and should closely monitor their blood sugar levels.

Summary

Woman holding kale

Scientists 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 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 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.

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

  1. Despres JP, Lamarche B, Mauriege P, et al. Hyperinsulinemia as an independent risk factor for ischemic heart disease. N Engl J Med. 1996 Apr 11;334(15):952-7.
  2. Garcia-Carretero R, Vigil-Medina L, Mora-Jimenez I, et al. Cardiovascular risk assessment in prediabetic patients in a hypertensive population: The role of cystatin C. Diabetes Metab Syndr. 2018 Sep;12(5):625-9.
  3. Mijajlovic MD, Aleksic VM, Sternic NM, et al. Role of prediabetes in stroke. Neuropsychiatr Dis Treat. 2017;13: 259-67.
  4. Mohan R, Jose S, Mulakkal J, et al. Water-soluble polyphenol-rich clove extract lowers pre- and post-prandial blood glucose levels in healthy and prediabetic volunteers: an open label pilot study. BMC Complement Altern Med. 2019 May 7;19(1):99.
  5. Available at: http://www.diabetes.org/diabetes-basics/statistics/. Accessed July 25, 2019.
  6. Available at: http://www.aarp.org/ppi/info-2018/the-facts-about-prediabetes-and-older-americans.html. Accessed July 25, 2019.
  7. Available at: https://www.health.ny.gov/diseases/conditions/diabetes/prediabetes/. Accessed May 15, 2019.
  8. Huang Y, Cai X, Mai W, et al. Association between prediabetes and risk of cardiovascular disease and all cause mortality: systematic review and meta-analysis. BMJ. 2016 Nov 23;355:i5953.
  9. Pilkington R, Taylor AW, Hugo G, et al. Are Baby Boomers healthier than Generation X? A profile of Australia’s working generations using National Health Survey data. PLoS One. 2014;9(3):e93087.
  10. Miranda AM, Steluti J, Fisberg RM, et al. Association between Polyphenol Intake and Hypertension in Adults and Older Adults: A Population-Based Study in Brazil. PLoS One. 2016;11(10):e0165791.
  11. Petrick JL, Steck SE, Bradshaw PT, et al. Dietary intake of flavonoids and oesophageal and gastric cancer: incidence and survival in the United States of America (USA). Br J Cancer. 2015 Mar 31;112(7):1291-300.
  12. Tresserra-Rimbau A, Guasch-Ferre M, Salas-Salvado J, et al. Intake of Total Polyphenols and Some Classes of Polyphenols Is Inversely Associated with Diabetes in Elderly People at High Cardiovascular Disease Risk. J Nutr. 2016 Mar 9.
  13. Wedick NM, Pan A, Cassidy A, et al. Dietary flavonoid intakes and risk of type 2 diabetes in US men and women. Am J Clin Nutr. 2012 Apr;95(4):925-33.
  14. Yeon JY, Bae YJ, Kim EY, et al. Association between flavonoid intake and diabetes risk among the Koreans. Clin Chim Acta. 2015 Jan 15;439:225-30.
  15. Zamora-Ros R, Forouhi NG, Sharp SJ, et al. The association between dietary flavonoid and lignan intakes and incident type 2 diabetes in European populations: the EPIC-InterAct study. Diabetes Care. 2013 Dec;36(12):3961-70.
  16. Issac A, Gopakumar G, Kuttan R, et al. Safety and anti-ulcerogenic activity of a novel polyphenol-rich extract of clove buds (Syzygium aromaticum L). Food and Function. 2015;6(3):842-52.
  17. Nm J, Rm R, G G, et al. Beyond the flavour: a de-flavoured polyphenol rich extract of clove buds (Syzygium aromaticum L) as a novel dietary antioxidant ingredient. Food Funct. 2015 Oct;6(10):3373-82.
  18. Jose S, Ratheesh M, Asha I, et al. Hepatoprotective effect of clove bud polyphenols (Syzygium aromaticum L.) (Clovinol®) by modulating alcohol induced oxidative stress and inflammation. Journal of Food Research. 2018;7(1):10-20.
  19. Kleemann R, van Erk M, Verschuren L, et al. Time-resolved and tissue-specific systems analysis of the pathogenesis of insulin resistance. PLoS One. 2010 Jan 21;5(1):e8817.
  20. Nathan DM, Davidson MB, DeFronzo RA, et al. Impaired fasting glucose and impaired glucose tolerance: implications for care. Diabetes Care. 2007 Mar;30(3): 753-9.
  21. Barclay AW, Petocz P, McMillan-Price J, et al. Glycemic index, glycemic load, and chronic disease risk--a meta-analysis of observational studies. Am J Clin Nutr. 2008 Mar;87(3):627-37.
  22. Ceriello A. Postprandial hyperglycemia and diabetes complications: is it time to treat? Diabetes. 2005 Jan;54(1):1-7.
  23. Cavalot F, Petrelli A, Traversa M, et al. Postprandial blood glucose is a stronger predictor of cardiovascular events than fasting blood glucose in type 2 diabetes mellitus, particularly in women: lessons from the San Luigi Gonzaga Diabetes Study. J Clin Endocrinol Metab. 2006 Mar;91(3):813-9.
  24. Abbatecola AM, Rizzo MR, Barbieri M, et al. Postprandial plasma glucose excursions and cognitive functioning in aged type 2 diabetics. Neurology. 2006 Jul 25;67(2):235-40.
  25. Kato M, Tani T, Terahara N, et al. The Anthocyanin Delphinidin 3-Rutinoside Stimulates Glucagon-Like Peptide-1 Secretion in Murine GLUTag Cell Line via the Ca2+/Calmodulin-Dependent Kinase II Pathway. PLoS One. 2015;10(5):e0126157.
  26. Hidalgo J, Flores C, Hidalgo MA, et al. Delphinol(R) standardized maqui berry extract reduces postprandial blood glucose increase in individuals with impaired glucose regulation by novel mechanism of sodium glucose cotransporter inhibition. Panminerva Med. 2014 Jun;56(2 Suppl 3):1-7.
  27. Alvarado J, Schoenlau F, Leschot A, et al. Delphinol(R) standardized maqui berry extract significantly lowers blood glucose and improves blood lipid profile in prediabetic individuals in three-month clinical trial. Panminerva Med. 2016 Sep;58(3 Suppl 1):1-6.

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