Bitter substances – why we need bitters

27. May 2024 from Jutta Hannemann
Milk thistle (an Amara aromatica) has been used as a medicinal plant since ancient times.

Bitter substances have long been known for their health-promoting effects. Even in ancient times, bitter substances were used to treat a wide variety of health problems (1). For a long time, bitters were held in low esteem, but in recent years bitter substances have once again enjoyed great popularity due to their health-promoting properties.

Bitter is one of the five basic flavours, along with sweet, sour, salty and umami (2). Umami is less well known, means "delicious" in Japanese and describes a meaty flavour (2; 3). We owe the ability to perceive the different types of flavour to the taste receptors located on the tongue and in the mouth (2).

What are bitter substances?

Bitter substances are very different chemical compounds that do not have a standardised structure. The only thing they have in common is their bitter flavour. In nature, they are found in many vegetables and medicinal herbs and protect the plant from predators. Typical natural bitter substances are, for example, secondary plant substances and amino acids (1).

Why do we avoid bitter foods?

Most people are not particularly fond of bitter foods. This natural aversion is innate: even newborn babies prefer sweet foods to bitter ones. This is our body's defence mechanism to protect itself from potentially toxic substances. This is because most toxic substances found in nature taste bitter (1). Sweet, on the other hand, is considered a "safety flavour" because there are no naturally occurring toxins that taste sweet. Instead, we associate sweetness with fast and good sources of energy.

Interestingly, only a single receptor is responsible for the perception of sweet and sour flavours on our tongue. For bitter, on the other hand, there are 25 receptors (4). We therefore perceive bitter much more strongly than sweet, for example. These 25 receptors can recognise tens of thousands of different bitter substances (5) - a sophisticated protective system against potentially toxic substances. But not everyone perceives bitterness in the same way. Scientists have discovered that how bitter we perceive something depends on our genes (6).

In the course of our lives, our innate rejection of bitter flavours changes as a result of our experiences and we are able to become accustomed to bitter tastes. Nevertheless, bitter flavours have gradually been bred out of vegetables in recent decades. As a result, we have become accustomed to milder flavours. The good news is that we can also get used to bitter flavours again (1).

Why bitter substances?

But why should we get used to bitter flavours? Bitters are currently experiencing a real comeback. And rightly so, as they have a number of positive effects on our health:

Bitter substances ensure that the flow of saliva is stimulated and more stomach acid is produced. They therefore aid digestion and make food more digestible (1). They also stimulate the function of the liver and gallbladder. As a result, the liver produces more bile, which in turn stimulates fat digestion and helps the liver to detoxify (7). Bitter substances also have a positive effect on intestinal activity and can thus facilitate the absorption of nutrients (8).

New studies suggest that bitter substances can stimulate the production of insulin in the pancreas. They thus ensure that the blood sugar level, which rises after eating, falls again more quickly and thus contribute to better blood sugar regulation (9; 10).

Bitter substances can also support weight loss. In contrast to sweet or salty foods, which make you crave more, bitter substances have an appetite-suppressing effect. By docking onto intestinal cells, they release a hormone produced by the body that signals to the body that it is full (9). Bitter substances can also reduce cravings for sweets.

Many bitter substances also have antioxidant properties and are able to activate the immune system (8; 11).

New findings also show that bitter receptors are not only found in the mouth, but also in many other body tissues. Researchers have been able to detect them in the digestive tract, lungs, immune cells, skin, heart and even brain cells (4; 12). Exactly what functions they have there is still largely unclear. However, it is certain that they are an important component of the innate immune system (4).

Natural bitter substances

Bitter substances are found in many fruits and vegetables, as well as in numerous medicinal plants. In herbal medicine, bitter-tasting plants that have health benefits are known as amara (Latin for bitter) (1). Amara have been an important part of naturopathy since ancient times. They are categorised according to their properties (1; 11):

  • Amara pura (pure bitters): Pure bitter remedies are, for example, yellow gentian, artichoke, dandelion root and centaury.

  • Amara aromatica (bittering agents and essential oils): In addition to bitter substances, plants in this group also contain essential oils, such as milk thistle, sage, yarrow, angelica root, hop cones and wormwood.

  • Amara acria (bitter remedy with pungent substances): These medicinal plants contain bitter and pungent substances, such as ginger and turmeric.

  • Amara mucilaginosa (bittering agent with mucilage): This includes plants that contain bitter substances and mucilage, for example Iceland moss.

  • Amara salina (high-salt bitters): This group includes bitter remedies rich in salt, such as dandelion root and dandelion herb.

  • Amara astringentia (astringent bitters): In addition to astringent bitter substances, these plants also contain tannins and tannins, such as cinchona bark.

Many well-known medicinal plants contain bitter substances that have liver-protecting, choleretic, digestive, appetite-stimulating and numerous other effects on health. These include, among others:

Known medicinal plants with bitter substances

Milk thistle Has been used as a medicinal plant since ancient times (13). It is considered to be liver-protective and helps to detoxify the liver (14; 15).

Artichoke It is said to protect the liver, stimulate the gall bladder and aid digestion. It is also said to have appetising, antioxidant and cholesterol-lowering properties (11; 16; 17).

Yellow gentian Is one of the most bitter plants known (12). Amarogentin, which is found in the root of the yellow gentian, is even considered to be the most bitter naturally occurring substance (12). It has appetising, gallic and digestive properties (14; 18).

Dandelion Has many different effects: digestive, gallbladder stimulant and appetite stimulant (14; 19).

Peppermint Known as a medicinal plant for centuries, it has an astonishing number of positive effects on the body (20). Among other things, it promotes the flow of bile and thus helps with digestion (14; 20).

Curcuma Belongs to the ginger family. It has long been used in traditional Chinese medicine (Pharmawiki). It is said to have choleretic and antioxidant properties (14; 21).

Fennel Contains bitter fenchone. Known to have digestive, antispasmodic and antimicrobial properties (14; 22).

Ginger Contains bitter and pungent substances that give it its pungent flavour. Has an antioxidant, digestive, antimicrobial and antispasmodic effect (14; 23).

Saffron Also used as a spice. Contains bitter substances that have antioxidant, anti-inflammatory and antispasmodic properties (24).

These are just a few selected medicinal plants containing bitter substances with a positive effect on health. There are of course many more.

Bitter substances in our diet

Apart from medicinal plants, bitter substances are found in many fruits, vegetables and herbs (11; 25), albeit in lower concentrations than in medicinal plants containing bitter substances. These foods contain significant amounts of bitter substances:

  • Fruits: grapefruit, lemon, pomelo, kumquat, pomegranate
  • Salads: chicory, radicchio, rocket, endive, cress
  • Cabbage varieties: Brussels sprouts, kale, savoy cabbage, broccoli
  • Vegetables: radish, radish, asparagus, fennel, olives, artichoke
  • Herbs and spices: Thyme, rosemary, chervil, sage, tarragon, bay leaf, caraway, aniseed, cinnamon, ginger, mustard

How can we integrate bitter substances into our diet?

Integrating more bitter substances into our diet can be a challenge because we are no longer used to bitter flavours. However, you can train yourself to like bitter flavours. The more often we eat bitter foods, the faster we get used to the flavour again (1).

Some practical tips that can help us to consume more bitter substances:

  • Experiment with new foods: Incorporate bitter vegetables, herbs and spices into your diet or start your meal with a small portion of bitter salad or a sip of bitter herbal tea.
  • Combine bitter flavours with others: Bitter foods often harmonise perfectly with other flavours to soften their intense taste. For example, try combining bitter leafy vegetables with sweet fruits or creamy sauces.
  • Add bitters to your favourite dishes: bitter herbs and spices such as thyme, rosemary, turmeric and ginger are an enrichment for many dishes.
  • If you are unable to integrate more bitter foods into your meals, you have the option of taking dietary supplements containing bitter substances.

Attention toxic!

  • If pumpkin plants such as courgettes, pumpkins or cucumbers taste bitter, you should avoid them: Hands off!
  • Their bitterness is not due to health-promoting bitter substances, but to poisonous cucurbitacins and there is an acute risk of poisoning.
  • The fatal thing is that these toxins are heat-stable and hardly soluble in water, which means that even cooking cannot harm them. Environmental stress (heat, drought, temperature fluctuations) but also incorrect storage can lead to increased levels of cucurbitacins in cucumbers and courgettes (1).
  • Home-grown edible pumpkins can have increased levels if they are grown in the garden next to ornamental pumpkins and the seeds of the harvested pumpkins are sown again the following year (1).
  • Therefore: leave bitter cucumbers, courgettes and gherkins on the left.


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Jutta Hannemann

I am a freelance medical writer and count various companies in the health care industry among my clients. After studying ecotrophology at the Technical University of Munich, I first worked in the food industry for over 10 years before taking the step into self-employment in 2010. This allows me to optimally combine my interest in scientific contexts and my passion for scientific writing. My work focuses on all topics related to nutrition, health and well-being.