Bilberry and blueberry: how are they different?

Bilberry and blueberry are related but different fruits. Bilberry (Vaccinium myrtillus) is a wild shrub of northern Europe whose berries are coloured right through, with deep red flesh. The blueberry sold in shops is usually the cultivated northern highbush blueberry (Vaccinium corymbosum), whose flesh is pale because its pigment sits in the skin. Both get their colour from anthocyanins, but the amounts and types differ: a German study found up to 1,017 mg of anthocyanins per 100 g in fresh bilberries and up to 438 mg in fresh blueberries. Delphinidin and cyanidin forms are the largest groups in bilberry, and malvidin forms in blueberry.

In short:

• Species: bilberry is Vaccinium myrtillus; the usual cultivated blueberry is Vaccinium corymbosum
• Where they grow: bilberry mostly wild in northern Europe; highbush blueberry mostly cultivated
• Flesh colour: deep red in bilberry, pale in blueberry
• Anthocyanins: amounts and main types differ (see the tables); delphinidin and cyanidin forms lead in bilberry, malvidin forms in blueberry
• Other compounds: blueberry had more chlorogenic acid and rutin in one study, and hydroxycinnamic acids lead in blueberry

This article compares the two berries by species, colour and the compounds measured in them. For another berry of the same genus, see What is cranberry, and what compounds does it contain?, and for a berry from a different plant family, see What is elderberry, and what is in the berries?

Are bilberry and blueberry the same plant?

They are close relatives but different species. Both belong to the genus Vaccinium in the heath family (Ericaceae), the same genus as cranberry.

Bilberry

The US National Center for Complementary and Integrative Health (NCCIH) says the bilberry bush is native to northern areas of Europe, the northern United States and Canada, and that its dark berries resemble blueberries. NCBI Taxonomy, the US National Library of Medicine's species database, lists it as Vaccinium myrtillus, with the common names common bilberry and whortleberry. The bilberries in the studies below came from Finland, Slovenia, Germany and the Italian Alps.

Blueberry

"Blueberry" covers several Vaccinium species. The one used in most studies of cultivated blueberries is Vaccinium corymbosum, which NCBI Taxonomy calls the northern highbush blueberry. Another species, Vaccinium angustifolium, is the lowbush blueberry, and some cultivars are crosses between the two, such as 'Northblue', used in one of the Finnish studies.

Why is bilberry dark inside while blueberry is pale?

The difference is in where the plant makes its pigment.

Pigment in the flesh or only in the skin

A 2022 study from New Zealand's Institute for Plant and Food Research, with the University of Auckland and UiT The Arctic University of Norway, compared the skin and flesh of developing bilberry and highbush blueberry fruit. It describes wild bilberry as having deep red flesh and blueberry as having non-pigmented flesh. The researchers found a set of regulatory proteins (MYB transcription factors) that switch on anthocyanin production. These were active in bilberry flesh but showed minimal activity in blueberry flesh, so anthocyanins were absent there.

What the Finnish comparison found

A 2008 study from the Universities of Kuopio and Oulu in Finland compared the flowers, fruit skin and pulp, leaves and underground stems of bilberry and the blueberry cultivar 'Northblue'. The most striking difference in the fruit was that hydroxycinnamic acids were the main phenolic compounds in blueberry, while bilberry had a much higher anthocyanin content, particularly in the pulp. The difference was already visible at the flower stage.

How much anthocyanin do bilberries and blueberries contain?

Anthocyanins are water-soluble plant pigments, red in acid and blue in alkaline conditions. Several European studies have measured them in both berries.

Amounts measured in studies

Sources: Müller and colleagues (2012), Može and colleagues (2011), Lätti and colleagues (2008). The studies expressed their results in different ways, so figures in different rows, and figures per fresh and per dry weight, are not directly comparable.

The German team at the University of Kaiserslautern used 15 authentic anthocyanin standards and found contents up to 53% higher in bilberries and 64% higher in blueberries than earlier figures calculated as cyanidin-3-glucoside. The method used therefore changes the number, which is one reason studies disagree.

Amounts vary within each fruit

The Finnish study of wild bilberries analysed berries from 179 plants in 20 populations along a south-to-north line of about 1,000 km. It found extensive variation within and between populations, and significantly lower anthocyanins in the south than in the central and northern regions. A 2015 study in the Alps of northern Italy found that bilberries accumulated more anthocyanins along an altitude gradient of about 650 m, while in the highbush blueberry 'Brigitta Blue', seasonal differences, especially temperature, had a major influence.

Do bilberry and blueberry contain the same types of anthocyanin?

Both contain about 15 anthocyanins, built on the same few coloured cores (delphinidin, cyanidin, petunidin, peonidin and malvidin) with different sugars attached. What differs is the proportion.

The main types in each berry

Source: University of Ljubljana, 2011, in cyanidin-3-glucoside equivalents; a dash means the summary of the study gives no separate figure. Bilberries came from seven locations in Slovenia and blueberries from one.

Other studies point the same way. The Kaiserslautern team found that delphinidin-3-glucoside, delphinidin-3-galactoside and cyanidin-3-arabinoside were the major anthocyanins in fresh bilberries and bilberry juices, while fresh blueberries had higher amounts of malvidin-3-arabinoside and petunidin-3-galactoside. A 2009 study from Kaunas University of Medicine in Lithuania found cyanidin to be the dominant anthocyanidin in bilberry and malvidin in blueberry, and the highest total anthocyanins in the skins of blueberry cultivars.

The mix also changes with place

In the Finnish study, delphinidin forms dominated in northern bilberries and cyanidin forms in southern ones. In the Alpine study, delphinidin and malvidin forms rose with altitude, while cyanidin and peonidin forms stayed the same. The profile of a bilberry therefore depends partly on where it grew.

What other compounds differ between the two berries?

Anthocyanins are not the whole picture. The Slovenian study also measured other phenolic compounds, and for some of them blueberries had more.

Source: University of Ljubljana, 2011. This was the first time rutin was identified in these berries.

This matches the Finnish finding that hydroxycinnamic acids, the group that includes chlorogenic acid, were the main phenolic compounds in the fruit of the blueberry hybrid 'Northblue'. The two berries therefore have different overall compositions, with more anthocyanins in bilberry and more of these acids in blueberry.

What about juice?

The Kaiserslautern team also tested nine juices and four nectars sold in Germany. Bilberry juices had 1,610 to 5,963 mg of anthocyanins per litre and bilberry nectars 656 to 1,529 mg, while blueberry juice had 417 mg per litre and blueberry nectars 258 to 386 mg. The limits: these were a small number of products from one country.

What nutrients are in blueberries?

USDA FoodData Central lists nutrients for raw blueberries; we did not find a comparable entry for bilberries there. The last column compares each value with the Thai Reference Daily Intake (Thai RDI).

Source: USDA FoodData Central, raw blueberries (SR Legacy). The share of the Thai RDI is our comparison.

Is there a recommended daily amount of bilberry or blueberry?

No. Bilberry and blueberry are fruits, and anthocyanins are plant pigments, not nutrients, so none of them has a value in the Thai Reference Daily Intakes (Thai RDIs). The Thai RDIs cover nutrients that these fruits contain in small amounts, such as vitamin C (100 mg a day) and vitamin K (60 µg a day). For the full list, see What are the Thai daily reference amounts for each nutrient?

Who should talk to a doctor or pharmacist?

Bilberry leaves

NCCIH says bilberry leaves may be unsafe in high doses or for long periods.

People who take regular medication

NCCIH says people who take any type of medicine should talk with a health care provider before using bilberry or other herbal products, because some herbs and medicines interact in harmful ways. If you take medication regularly, ask a doctor or pharmacist first.

Pregnant and breastfeeding women

NCCIH says little is known about bilberry in amounts greater than those found in foods during pregnancy or breastfeeding. If you are pregnant or breastfeeding, ask a doctor or pharmacist before eating bilberry in amounts greater than those in food.

Dietary supplements are not intended to prevent, treat or cure any disease.