Saponins are plant-derived molecules that may help to reduce cholesterol levels and lower blood sugar levels. Black garlic is thought to contain at least 10 varieties of saponins – here's how they could affect health.
We rely on plants to feed us, make our clothes, build our homes and a whole lot more. Plants have evolved a complex defence system much like our own immune system. They try to deter predators from eating them and like us, they avoid infection by pathogens and parasites. Plants use a wide range of defences to protect themselves; these are either physical, like the spikes of a cactus, or chemical, using saponins and other molecules to deter predators. Saponins are found in black garlic and many other plants, to protect them from infection and to help them to absorb vital nutrients from their environment. Yet in the human body, saponins could have very different effects.
There are 10 different varieties of saponins found in black garlic, of which two are believed to have antimicrobial properties. These are known as agigenin 3-O-trisaccharide and gitogenin 3-O-tetrasaccharide. In a 2012 study, both of these garlic saponins actively suppressed two species of fungus – they have been touted as potential future medicines, due to their anti-pathogen properties1.
Black garlic saponins may help to lower cholesterol levels, according to research based on animal models. Put simply, these saponins have the ability to latch onto cholesterol molecules, stopping them from being reabsorbed and helping the body to excrete them rather than store them inside blood vessels2.
Having too much cholesterol in the bloodstream can have serious long-term consequences, often leading to a disease called atherosclerosis – this is when cholesterol, fat and other molecules gradually settle inside blood vessels, slowly narrowing them. This creates a strain on the heart and can potentially lead to a blood clot or stroke if left untreated3. We can't be sure that black garlic saponins will have this cholesterol-busting effect in humans, as there isn't enough research into this. However, legume saponins have been studied and they have been shown to lower cholesterol, lower blood glucose response and lower blood lipid levels, all of which can be beneficial.
Black garlic can help to reduce cholesterol levels and support a healthy heart, although this is most likely thanks to allicin and other organosulfur compounds, not saponins. Taking a black garlic supplement has also been linked with decreasing blood pressure in people with hypertension5. One study has found that black garlic saponins can protect may also protect human endothelial cells from oxidative stress6.
Garlic isn't nature's only sources of saponins; they're also found in sea-cucumbers, starfish and many species of plants. If you've ever eaten quinoa, kidney beans or any other legume, you've consumed saponins.
Black garlic contains around 0.04% to 0.11% saponins by weight, an extremely small amount. Only a fraction of these molecules is absorbed by the body, usually via the small intestine7. Some plant saponins, including those extracted from soaproot and yucca plants, are extremely toxic – they have even been used as poisons by indigenous tribes across South America. However, the 10 saponins identified in black garlic are not believed to be toxic to human health, especially at such low volumes. Black garlic is enjoyed by people around the globe, with relatively few side effects and zero cases of toxicity reported8.
Of all the many molecules and compounds within black garlic, saponins might have the lowest impact on health, especially at such low amounts. Garlic contains hundreds, if not thousands, of different molecules, each with different effects on health. Many of these have only recently been identified and isolated, so there isn't much research into which molecules interact with the human body.
Compared to allicin, which can help to reduce cholesterol and support heart, saponins have relatively little to no effect on health, according to current research6. We've formulated garlic and black garlic supplements specifically to support a healthy heart. Find out more about what's in our Kwai Heartcare+ with Japanese Black Garlic supplement here.