Fresh garlic contains a substance called alliin and an enzyme called alliinase.
When garlic is crushed, chopped, or chewed, its cellular structures are disrupted. Alliin and alliinase come into contact, allowing the enzyme to convert alliin into allicin.
Allicin is responsible for much of the characteristic sharp smell and taste of freshly crushed garlic.
It is also a reactive compound that can quickly transform into other sulfur-containing substances.
During black garlic production, heat and aging alter this chemical system. The activity of alliinase is affected, and the amount of allicin generally decreases.
At the same time, other compounds may become more prominent.
One compound receiving considerable research attention is S-allyl-cysteine, commonly abbreviated as SAC.
SAC is a water-soluble sulfur-containing compound that can be present in higher concentrations in black garlic than in fresh garlic, depending on the processing conditions.
Researchers have investigated SAC and other sulfur compounds for their potential biological activities.
However, a higher concentration of a particular compound does not automatically mean that the food produces a greater health benefit in humans.
The amount consumed, the compound's absorption, its metabolism, and the health condition being studied all matter.
The transformation of garlic during aging is chemically complex, and no single compound explains every possible effect of black garlic. <Cite refs={["turn825400search0"]} />
9. BLACK GARLIC AND ANTIOXIDANTS: WHAT DOES THE EVIDENCE SAY?
Antioxidants are substances that can interact with reactive molecules involved in oxidation.
Oxidative stress occurs when the production of reactive molecules exceeds the body's ability to manage them effectively. It has been studied in relation to aging and a variety of chronic diseases.
Black garlic is often promoted as an antioxidant-rich food.
Some laboratory studies have found that black garlic contains higher concentrations of certain antioxidant compounds than fresh garlic. These may include polyphenols and other substances formed or modified during aging.
However, there are several important points to understand.
Antioxidant activity in a laboratory is not the same as a proven health benefit
Researchers can measure antioxidant activity using chemical tests in a laboratory.
These tests can help identify compounds that interact with particular reactive molecules under controlled conditions.
But the human body is much more complicated.
A compound that demonstrates antioxidant activity in a test tube may be poorly absorbed, rapidly metabolized, or present in a quantity too small to produce the same effect in the body.
Therefore, laboratory findings should not automatically be translated into claims that a food prevents cancer, reverses aging, or protects every organ.
The role of polyphenols
Polyphenols are a broad group of naturally occurring compounds found in many plant foods.
They are present in fruits, vegetables, tea, coffee, cocoa, and numerous other foods.
Some studies have reported increased polyphenol levels in black garlic compared with fresh garlic. The extent of this increase depends on the garlic and the aging conditions.
Polyphenols are being investigated for their possible effects on inflammation, oxidative stress, and metabolic health.
However, the overall health impact of consuming black garlic regularly is still being studied.
It is more accurate to say that black garlic contains compounds with potential biological activity than to claim that it provides a guaranteed antioxidant advantage for every person.
10. CAN BLACK GARLIC SUPPORT HEART HEALTH?
Heart health is one of the most frequently mentioned reasons people choose black garlic.
Some studies have investigated whether black garlic or black garlic extracts may influence blood pressure, cholesterol, blood vessel function, or other cardiovascular markers.
The findings are interesting, but they should be interpreted carefully.
Blood pressure
Some small human studies have reported changes in blood pressure after participants consumed certain black garlic preparations.
However, these studies may differ in:
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The type of black garlic used
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The dose or amount consumed
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The duration of supplementation
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The participants' existing health conditions
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Whether the product was whole garlic, an extract, or a supplement
These differences make it difficult to determine whether eating ordinary black garlic cloves produces the same results.
Black garlic should not be considered a replacement for prescribed blood pressure medication.
People with hypertension should continue to follow their healthcare professional's recommendations and should not discontinue treatment because they have started eating black garlic.
Cholesterol
Garlic has been investigated for its potential effects on blood lipid levels.
Some research suggests that certain garlic preparations may influence total cholesterol or LDL cholesterol. However, results have not been consistent across all studies.
Evidence specifically examining black garlic remains limited compared with the broader research on garlic.
It is also important to distinguish between a small change in a laboratory measurement and a demonstrated reduction in heart attacks, strokes, or cardiovascular deaths.
A food may influence a biomarker without necessarily producing a proven improvement in long-term clinical outcomes.
Blood vessel function
Researchers have also examined whether compounds found in garlic may influence the function of blood vessels.
Blood vessels need to remain flexible and respond appropriately to changes in blood flow.
Some experimental studies suggest that garlic-derived compounds may influence processes involved in vascular function.
However, more research is needed to determine the extent to which these effects occur in people who consume black garlic as part of their normal diet.
The practical conclusion is straightforward: black garlic can be included in a heart-healthy eating pattern, but it should not be treated as a standalone cardiovascular treatment.
11. BLACK GARLIC AND BLOOD SUGAR: CAN IT HELP?
Blood glucose regulation is another area of interest.
Some laboratory and animal studies have examined whether black garlic compounds may influence insulin sensitivity, glucose metabolism, or other processes involved in blood sugar regulation.
A limited number of human studies have also investigated garlic preparations and metabolic health.
However, the evidence is not strong enough to conclude that black garlic reliably prevents or treats diabetes.