Foods that Contain Glycosides and Their Diverse Effects

December 7, 2025 •

4 min read

Over 2,000 plant species contain cyanogenic glycosides, including several that are staple foods in different parts of the world. Glycosides are a large and diverse group of chemical compounds found naturally in many foods, composed of a sugar molecule bonded to a non-sugar component. These compounds have a range of functions, influencing everything from a food's flavor to its potential health effects, both positive and negative.

Quick Summary

Glycosides are natural compounds present in many foods, including fruits, vegetables, and legumes. Their effects vary greatly, ranging from beneficial antioxidant properties in flavonoid glycosides to potentially toxic effects in cyanogenic and cardiac glycosides. Proper food preparation is often necessary to mitigate risks and maximize health benefits.

Key Points

Cyanogenic Glycosides: Found in foods like cassava, sorghum, and bitter almonds, these can release toxic hydrogen cyanide if not properly prepared by methods like boiling or fermentation.
Flavonoid Glycosides: These beneficial antioxidant compounds are abundant in citrus fruits, berries, onions, and teas, and are linked to a reduced risk of chronic diseases.
Saponin Glycosides: Present in legumes like soybeans and chickpeas, as well as quinoa and spinach, saponins can lower cholesterol but may also have antinutritional effects.
Proper Preparation: Boiling and soaking are crucial for detoxifying foods with harmful glycosides, such as bitter cassava and raw bamboo shoots.
Diverse Health Effects: The impact of glycosides on health is highly varied, ranging from beneficial antioxidant and anti-inflammatory properties to potential toxicity if consumed in excessive amounts.
Pharmaceutical Interest: Many plant glycosides, including cardiac glycosides from the foxglove plant, have been isolated for their potent medicinal properties.

Glycosides are organic compounds widespread throughout the plant kingdom, acting as defense mechanisms, pigments, and flavor compounds. Structurally, each glycoside consists of a sugar portion (the glycone) and a non-sugar portion (the aglycone). The nature of the aglycone determines the compound's properties, including its biological activity and health implications. While some glycosides are harmless or even beneficial, others can be toxic if consumed in high concentrations or improperly prepared.

Cyanogenic Glycosides

Cyanogenic glycosides are a well-known class of plant toxins that can release hydrogen cyanide when the plant tissue is damaged, such as by chewing or processing. This is a defense mechanism against herbivores.

Foods containing cyanogenic glycosides:

Cassava: Both sweet and bitter varieties contain the cyanogenic glycosides linamarin and lotaustralin. Bitter cassava has much higher levels and requires extensive processing like prolonged soaking, peeling, and boiling to be safe for consumption.
Sorghum: The cyanogenic glycoside dhurrin is present, particularly in the leaves of younger plants. Levels decrease as the plant matures.
Stone Fruit Seeds and Pits: The seeds or kernels of apples, apricots, cherries, and peaches contain amygdalin. For example, bitter apricot kernels have particularly high concentrations of amygdalin and can be highly toxic if not properly processed.
Bamboo Shoots: Raw bamboo shoots contain taxiphyllin, a cyanogenic glycoside. Boiling the shoots adequately removes the cyanide.
Almonds: Bitter almonds contain significant amounts of amygdalin, unlike the sweet almonds commonly consumed.

Flavonoid Glycosides

These are a large and diverse group of compounds where the aglycone is a flavonoid. Flavonoid glycosides are recognized for their antioxidant and anti-inflammatory properties, offering significant health benefits.

Foods containing flavonoid glycosides:

Citrus Fruits: Oranges and lemons are rich in flavanones like hesperidin and naringenin, found mainly in the peels and membranes.
Berries and Grapes: Many berries, like blueberries, blackberries, and strawberries, contain anthocyanidins, the pigments that give them their rich colors.
Onions: A significant source of the flavonol quercetin.
Green and Black Tea: Contain a variety of flavonols and catechins, such as theaflavins and thearubigins.
Soybeans: A primary dietary source of isoflavonoids like genistein and daidzein.
Kale and Other Leafy Greens: Rich in flavonols like quercetin and kaempferol.
Dark Chocolate: Contains flavan-3-ols.

Saponin Glycosides

Saponins are characterized by their soap-like foaming properties and are found in various plant-based foods. They can have both antinutritional and beneficial effects, including cholesterol-lowering properties.

Foods containing saponin glycosides:

Legumes: A major source of saponins, especially soybeans, chickpeas, and beans from the Phaseolus vulgaris species.
Quinoa: High in saponins, which are found in the outer coating of the seed.
Spinach: Contains saponins, which can be seen as a frothy foam when boiled.
Ginseng: Known for its high concentration of steroid and triterpenoid saponins, known as ginsenosides.

Comparison of Major Glycoside Types


Feature	Cyanogenic Glycosides	Flavonoid Glycosides	Saponin Glycosides
Associated Foods	Cassava, bitter almonds, sorghum, bamboo shoots	Citrus fruits, berries, onions, tea, dark chocolate	Legumes (soybeans, chickpeas), quinoa, spinach, ginseng
Primary Aglycone	Cyanohydrin group	Flavonoid (polyphenolic) structure	Steroid or triterpenoid structure
Mechanism of Action	Releases toxic hydrogen cyanide upon enzymatic hydrolysis.	Acts as antioxidants, anti-inflammatories, and enzyme modulators.	Creates soap-like foam; binds cholesterol, affects cell membranes.
Key Health Impact	Potentially lethal acute cyanide poisoning if improperly processed.	Associated with reduced risk of chronic diseases due to antioxidant effects.	Can lower serum cholesterol levels and have anti-cancer properties.
Preparation Consideration	Require extensive soaking, peeling, boiling, or fermentation to be safe.	Generally safe for consumption as part of a balanced diet.	Boiling can solubilize saponins, but does not always eliminate them completely.

Preparing Foods with Glycosides Safely

For foods containing potentially harmful glycosides, proper preparation is essential. Methods like soaking, cooking, and fermentation can effectively reduce or eliminate toxic compounds. For example, boiling bamboo shoots and extensively processing bitter cassava are standard practices. With saponin-rich foods like beans, discarding the frothy foam created during boiling can help reduce their concentration, though fermentation is more effective at elimination. It is important to be aware of the specific preparation methods required for any foods known to contain toxic glycosides.

Conclusion

Glycosides are a natural and integral part of many foods we consume, from everyday produce to staple crops. Their health effects are as diverse as their chemical structures. While flavonoid glycosides contribute to the antioxidant benefits of fruits and vegetables, other types, such as cyanogenic and saponin glycosides, require careful preparation to avoid adverse health effects. Understanding what foods have glycosides and how to properly prepare them is crucial for a safe and healthy diet, especially when consuming traditional or unfamiliar ingredients. The bioactive nature of these compounds highlights the complex interplay between plants and human nutrition.

References

ScienceDirect.com. "A comprehensive overview of cyanogenic glycosides: Toxicology, detection, and mitigation strategies." ScienceDirect, March 2025.
World Health Organization (WHO). "Natural toxins in food." WHO, March 2023.
National Institutes of Health (NIH). "Flavonoids: an overview." PubMed Central (PMC), May 2017.
ScienceDirect.com. "Saponins in food—A review." ScienceDirect, 1981.
National Institutes of Health (NIH). "Cardiac Glycosides as Immune System Modulators." PMC, May 2021.
ScienceDirect.com. "Anthraquinone Glycosides." ScienceDirect, January 2017.
ScienceDirect.com. "Glycoside - an overview." ScienceDirect, 2023.

Frequently Asked Questions

Glycosides are organic molecules where a sugar group is linked to a non-sugar functional group, known as the aglycone, via a glycosidic bond. They are naturally produced by plants and serve a variety of biological functions, from defense to providing color.

Common foods with cyanogenic glycosides include cassava (especially bitter varieties), sorghum, and the seeds of stone fruits like apricots and cherries. Raw bamboo shoots also contain this type of glycoside.

To reduce cyanogenic glycosides in cassava, it must be properly processed. This involves peeling, soaking, and cooking thoroughly, such as boiling or fermentation, to break down the compound and release the hydrogen cyanide.

No, not all glycosides are toxic. While cyanogenic and cardiac glycosides can be harmful or even lethal, others like flavonoid glycosides have beneficial antioxidant and anti-inflammatory properties.

Flavonoid glycosides are among the most beneficial, providing antioxidant and anti-inflammatory effects. They are found in foods like berries, citrus fruits, and green tea. Saponin glycosides in legumes may also help lower cholesterol.

Yes, apple seeds contain the cyanogenic glycoside amygdalin. However, the amount is small and the seeds are usually not chewed, so it poses minimal risk. Ingesting large quantities of crushed seeds could release enough cyanide to be harmful.

In the body, saponins can bind to cholesterol, which reduces the amount absorbed from the gut. This can contribute to lowering serum cholesterol levels. They are known for creating a foamy texture when boiled, which is why froth appears when cooking some legumes.