Luteolin: What the Plant Compound Is, Occurrence & Use

Luteolin is a secondary plant compound from the group of flavonoids, more precisely the flavones. The yellow natural pigment occurs in many herbs, vegetables and fruits and is closely related to other flavones such as apigenin. In recent years, luteolin has also been offered as a component of food supplements. Anyone dealing with it should first understand which substance it is chemically, in which foods it is found, in which forms it is available and what to pay attention to regarding selection, intake and safety. This guide classifies luteolin factually, without health-related efficacy promises, because for the EU no such claims are authorised for this substance.

What is luteolin?

Luteolin belongs to the polyphenols and there to the subgroup of flavones, to which apigenin also belongs. It is a yellow plant pigment and a typical secondary plant compound, that is, a compound that plants form, among other things, as a pigment, for defence and for protection, and which does not serve pure growth. The name derives from the Latin word for yellow. Chemically, luteolin differs from apigenin by an additional hydroxyl group.

For humans, luteolin is not an essential nutrient, so the body needs no fixed intake and forms no deficiency if intake is lacking. Like many flavones, luteolin is poorly water-soluble, which influences its absorption. It counts among the bioactive accompanying substances of a plant-rich diet and is studied in research, predominantly in the laboratory and in animal models. Authorised health claims for humans do not exist for it in the EU.

Occurrence in foods

Luteolin is contained in numerous plant-based foods, especially in certain herbs and vegetables. Frequently named sources are parsley, celery, thyme, oregano as well as peppers and some salads. The contents fluctuate clearly depending on variety, ripeness, cultivation conditions and preparation; dried herbs often contain more in relation to weight than fresh ones.

• Parsley and celery: count among the best-known luteolin sources, especially in dried form.
• Thyme and oregano: supply luteolin via dried herbs and spices.
• Peppers: contribute to the intake in colourful vegetable cooking.

Through a varied diet, smaller amounts of luteolin are taken in regularly. Anyone who wants to increase the proportion of flavonoids benefits from a colourful diet rich in herbs, fruit and vegetables, as is also recommended by expert societies such as the German Society for Nutrition. Using herbs generously, fresh or dried, is a simple way to increase the daily intake.

Forms as a food supplement

As a food supplement, luteolin is offered predominantly in capsules with a standardised content. The raw material is often obtained from luteolin-rich plants such as peanut shells or certain herbs. The contained amount is usually above what can be achieved through foods alone.

Since luteolin is poorly water-soluble, some products combine it with oils or special formulations in order to support absorption and increase bioavailability. Luteolin is also partly sold together with related flavones such as apigenin in combination preparations. For a sensible comparison, the actually stated pure luteolin content per portion is decisive, not the total amount of the extract. With combination products, it is worth looking at how much luteolin is actually contained in each case.

Intake and dosage

Binding official dosage recommendations for luteolin do not exist, since it is classified as a bioactive plant compound and not as an essential nutrient. Manufacturers state different amounts. Since luteolin is fat-soluble, intake is often recommended with a meal containing some fat, which can support absorption.

Some users take luteolin over several weeks, others use it more irregularly. For everyday use the following applies: orient yourself by the dosage statement of the respective product and do not exceed the recommended daily amount without professional advice. With secondary plant compounds, a higher dose does not automatically bring more benefit, and very high amounts from extracts are not sufficiently studied.

What to pay attention to when buying?

The most important statement when buying is the stated luteolin content per capsule or portion. Some products advertise with high extract amounts without stating the pure luteolin proportion, which makes comparison difficult. Reputable providers state origin, plant part used and standardised content transparently.

Additionally pay attention to a short ingredient list without unnecessary additives as well as to testing for residues and heavy metals, since plant extracts can be contaminated depending on origin. Combination preparations with further flavonoids can be practical, but make comparison of the individual amounts harder. An independent analysis certificate is a good sign of quality and purity. A light-protected packaging helps to preserve the sensitive pigment.

It is also sensible to compare the cost per daily dose instead of the pure package price, because products differ strongly in capsule number and luteolin content. Anyone who pays attention to plant-based capsule shells or wants to avoid certain additives finds the necessary details on the ingredient list. With combination preparations containing apigenin or other flavonoids, it is worth looking closely at what ratio the individual substances are contained in, since some products name luteolin prominently but supply only small amounts of it. Anyone who considers these criteria together can compare various offers fairly.

Safety and tolerability

In the amounts that are taken in through foods and herbs, luteolin is considered harmless. For highly concentrated extracts, less long-term data is available, which is why the manufacturer's statements should not be exceeded. If the raw material is obtained from peanut shells, people with a peanut allergy should check the declaration particularly carefully and, in case of doubt, avoid such products.

Like other polyphenols, luteolin can theoretically interact with medications, for example via the breakdown in the liver. If you regularly take medicines, are pregnant, breastfeeding or have health complaints, speak with your doctor before taking it. Food supplements do not replace a balanced diet or medical treatment.

Luteolin in the context of flavonoids

To classify luteolin correctly, a look at the large group of flavonoids to which it belongs helps. Flavonoids are an extensive class of secondary plant compounds that occur in almost all plant-based foods and are divided into several subgroups, including flavones, flavonols, flavanols and anthocyanins. Luteolin, like apigenin, counts among the flavones. These compounds are co-responsible for many colour tones in plants and fulfil protective functions there.

For nutrition, less the individual substance is decisive than the interplay of many flavonoids and further accompanying substances that one takes in through a plant-rich diet. Expert societies therefore emphasise the value of a varied diet with plenty of fruit, vegetables, herbs and wholegrain products, instead of highlighting individual substances in isolation. An isolated extract does supply a high amount of a single flavone, but cannot reproduce the diversity of a natural food matrix. This classification is helpful in order to assess the role of luteolin realistically.

Honestly put into perspective

Luteolin is a widespread, much-studied plant compound, whose significance for humans is, however, not yet conclusively clarified. A large part of the data comes from laboratory and animal experiments that cannot be directly transferred to humans. Authorised health claims do not exist in the EU, and highly concentrated extracts are not to be equated with the natural occurrence in herbs and vegetables. Anyone who eats a varied and plant-rich diet takes in luteolin regularly in small amounts anyway. An extract can sensibly complement such a diet, but not replace it, because the diversity of nutrients and fibre from whole foods cannot be reproduced by a single substance. Anyone who wants to try luteolin therefore does so best as a conscious supplement and not as a substitute for fresh herbs, vegetables and fruit in the diet.

Frequently Asked Questions (FAQ)

What is luteolin?

Luteolin is a secondary plant compound from the group of flavones, related to apigenin. It is a yellow natural pigment that occurs in herbs and vegetables and is not an essential nutrient for humans.

In which foods is luteolin found?

Frequent sources are parsley, celery, thyme, oregano and peppers. The contents fluctuate depending on variety and preparation. Through a varied diet one takes in smaller amounts regularly.

How is luteolin taken?

As a food supplement usually as a capsule, often with a fat-containing meal, since luteolin is poorly water-soluble. Binding official dosages do not exist; stick to the manufacturer's statements.

What should I pay attention to when buying?

Important is the stated pure luteolin content per portion, not just the extract amount. Also pay attention to origin, standardised content, few additives and testing for residues.

Is luteolin safe?

In the amounts from foods, luteolin is considered harmless. For highly dosed extracts there is less data. With peanut allergy, medication intake, pregnancy, breastfeeding or illnesses you should seek medical advice beforehand.