Spices tend to get dismissed, but one small clove packs more polyphenols than any of 452 foods researchers compared. A 12-week study in adults with prediabetes found that daily clove extract was linked to lower after-meal blood sugar and lower inflammation markers. Here is what the study did and did not test, and how people are trying a clove with their first cup of coffee. (Based on the insights of Dr. Mindy Pelz)
Key Takeaways
- A 2022 study followed 70 adults with prediabetes for 12 weeks on 250 mg of clove extract or 250 mg of glutathione, with no diet change.
- The clove group had lower after-meal blood sugar (31% vs 7%), lower fasting blood sugar (17%), lower inflammation markers (30% to 36%), and better blood fat results.
- The study used a clove extract. Whether a whole clove in coffee gives the same effect is not known.
- Clove ranked highest in polyphenols among 452 foods compared, which may help feed the gut microbiome.
- Use food amounts only (one or two whole cloves), check with your doctor if you take diabetes medicine or blood thinners, and never swallow clove oil.
What the Study Looked At
A study published in 2022 in the Journal of Functional Foods followed 70 adults with prediabetes, people whose blood sugar regulation was not good, for 12 weeks without any change to their diet. One group took 250 mg of clove extract a day. The other group took 250 mg of glutathione, the body’s master antioxidant, as a pill.
An important detail: the study used a clove extract, not a whole clove dropped in coffee. Whether a whole clove in your cup delivers the same amount is not known.
What the Researchers Reported
- Inflammation: two inflammation signals fell about 30% to 36% with clove, compared with 10% to 13% in the glutathione group.
- Antioxidant production: the clove group’s own glutathione production rose by 55%, compared with 9% in the glutathione pill group.
- Blood sugar: after-meal blood sugar fell by 31% with clove versus 7% with glutathione, and fasting blood sugar fell by 17%.
- Blood fats: total cholesterol dropped by 23%, triglycerides by 24% and LDL by 28%, while HDL rose by 15%.
These are striking numbers, but this was one 12-week study in a specific group, people with prediabetes, so the results should not be assumed to apply to everyone. Larger and longer studies would be needed to confirm them.
Why Cloves Come Up
As part of the same work, researchers compared 452 foods and found that clove contained the highest amount of polyphenols per 100 grams. Polyphenols help feed the gut microbiome, the trillions of bacteria involved in regulating inflammation, cholesterol and blood sugar. Clove also contains eugenol, which has antimicrobial properties, and laboratory and animal research suggests clove compounds may influence brain immune cells and BDNF, a protein involved in brain plasticity. That brain research was not part of this study and has not been shown in people.
How to Try a Clove Routine
- Drop one whole clove in your coffee. A whole clove stays in the cup as you sip and reheat. Powder mixes in differently and is an option too.
- Keep the cup simple. Sweetened creamers or added sugars can offset any blood sugar benefit.
- Stack spices, do not supersize them. One or two cloves a day is enough. Cinnamon, cardamom or fresh ginger can be added for flavor.
- Use it with your first meal. Chew a clove after a meal or stir ground clove into yogurt, chia pudding, oatmeal or lentils.
- Be consistent. The study ran for 12 weeks, so a one-off clove is not what was tested. Track how you feel, and if you check your own numbers, such as a glucose meter, A1C, cholesterol or CRP, you can see over 30, 60 or 90 days whether anything changes.
Safety and Common Sense
Use food amounts only. One or two whole cloves a day is far from the concentrated clove oil, which can be harmful and should never be swallowed. Cloves can affect blood sugar and blood clotting, so talk to your doctor first if you take diabetes medicine or blood thinners, or have a bleeding or liver condition, and do not use cloves as a substitute for treatment of diabetes. Watch for allergy, and stop if you notice any reaction.
The Bottom Line
Spices are concentrated sources of plant compounds, and clove stood out in this research. A single small study in people with prediabetes is a reason for curiosity, not a prescription. A clove in your coffee is an easy, low-risk experiment for most healthy adults, as long as it sits alongside the basics: balanced meals, movement, sleep and the care your doctor recommends.
Frequently Asked Questions
Does a clove in coffee lower blood sugar?
A 12-week study in adults with prediabetes found that daily clove extract was linked to lower after-meal and fasting blood sugar. It used an extract, so it is not known whether a whole clove in coffee has the same effect.
How many cloves should I use?
One or two whole cloves a day is the amount discussed. The study used 250 mg of clove extract. More is not better, and clove oil should never be swallowed.