By Adebowale Bello, Freelance Health Writer
Collection of African bitter kola on a white plate. Click on the image to enlarge.
Introduction
Humans have devised means of harnessing nature's numerous gifts and use them to improve their health and well-being. In Africa, one of these gifts of nature is bitter kola which is scientifically known as Garcinia kola.
In the three major ethnic languages of Nigeria (Hausa, Ibo and Yoruba), bitter kola is referred to as Namijin Goro, Aku ilu and Orogbo respectively.
Even though the name implies its taste, this fruit has been used for centuries in traditional African medicine and cultural practices. Traditional medicine is gaining a foothold and many countries are integrating it into their healthcare system. A whopping 80% of African countries rely extensively on traditional medicine thus emphasising its importance (1).
It's no surprise therefore that bitter kola plays a major role in traditional healthcare as it's packed with a variety of nutrients.
Figure 1. Distribution of Garcinia kola among African countries. Dark green are areas with a higher abundance, light green marks a lower abundance. Click on image to enlarge. Source: Manourova A et al
The bitter kola tree is native to the lush rainforests of West and Central African countries such as Ghana, Nigeria, Cameroon and Gabon (Figure 1). These evergreen trees can grow up to 30 metres tall, although they typically reach heights of 12 to 15 metres (figure 2).
Figure 2. Morphological features of Garcinia kola. (a) bark with a fresh cut; (b) seedlings; (c) leaf collection from one tree; (d) seeds (e) branches with ripening fruits; (f) trunk with typical irregular branching pattern. Click on image to enlarge. Source: Manourova A et al
The fruits are rounded berries, sometimes slightly flattened. Within these fruits lie the prized bitter kola seeds, which resemble kidney beans in shape (figure 3). Although the seeds have a notably bitter taste, there's a subtle late chewing sweetness that makes them unique and memorable.
Figure 3. Softened fruit pulp of Garcinia Kola showing the seeds inside. Click on image to enlarge. Source: Manourova A et al.
Bitter kola isn't just about its bold, bitter taste when eaten raw, it is packed with various essential nutrients.
Studies have revealed that bitter kola contains vitamins and minerals such as vitamin C, potassium, calcium and phosphorus (2), all of which help in immune building. It also contains carbohydrates, fat and protein.
While standing by the roadside with a friend of mine, an elderly woman displayed her wares nearby and some of the meagre items included bitter kola and kola nuts and that sparked up an interesting conversation, trying to guess which of the fruits was bitter kola or kola nut.
If you've come across these fruits but you're not familiar with them, you may use bitter kola and kola nuts interchangeably, however they're actually distinct fruits with some key differences (See Table 1).
Here's how you can tell them apart:
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Table 1:Showing key differences betwen bitter kola and kola nut. Click on image to enlarge.
Bitter kola boasts a variety of compounds which play a key role in its multi-protective ability. Some of these compounds like Garcinianin, Kolaviron and Gakolanone can only be found in bitter kola.
If you don't eat bitter kola, here are 10 reasons why you should try it out.
As the malaria parasite becomes resistant to drugs, it's necessary to look at other avenues. Bitter kola contains Kolaviron, and studies have shown it is effective against malaria.
On studying its effect in mice induced with the malaria parasite, it was discovered that this compound destroys enzymes produced by the malaria parasite while protecting the red blood cell from further damage (3).
However, further research is required to support this scientific study.
Research has shown that bitter kola may contain chemical agents (benzophenones and flavanones) that are useful in fighting against bacteria. Some of the bacteria that bitter kola has proven effective against include Staphylococcus aureus, Streptococcus faecalis, Escherichia coli and Klebsiella sp. (4, 5).
Eating or taking extracts of bitter kola blended with honey has been shown to help combat coughs, bacterial and viral infections.
3. Contains Antioxidants for Immune Boosting and Brain Health
Antioxidants are compounds that prevent cell damage by neutralizing cellular waste products known as free radicals. Bitter kola contains several antioxidant-containing compounds like flavonoids, anthocyanins and phenolic acids (4, 5, 6).
This protective ability improves your immune health, sharpens brain function and mental health.
Though it is unclear how the mechanism works, Research suggests that bitter kola may protect the liver. It is suggested that this is possible through the production of enzymes that detoxify drugs (7, 8)
5. Relieves Rheumatism Due to Anti-Inflammatory Effects
The enzyme Cyclooxygenase creates two chemicals - COX-1 and COX-2, and they play a key role in the inflammatory process. Nitric oxide is also present in large amounts during inflammation.
Bitter kola contains anti-inflammatory properties that reduce or inhibit these compounds, thereby preventing swelling and body pain especially with regards to fevers and aches (7).
Africans have been known to chew on bitter kola for the relief of knee pains due to arthritis.
Tannins found in bitter kola and their secondary metabolites have been known for their natural treatment of intestinal disorders such as diarrhea and dysentery.
7. Anticancer and wound healing
Tannins have also been reported to have remarkable potential in cancer prevention. Together with phlobatannins they exhibit wound healing properties (9)
African folklore acclaim the chewing of bitter cola for its male invigorating aphrodisiac properties. However, a recent study in rats found no supporting evidence for this claim (10).
Whether the finding in animal studies can be directly translated into humans is debatable. More clinical research is needed to validate the folkloric pro-sexual effects of bitter kola on human males.
A recent systematic review concluded that Kolaviron (KV) is helpful in managing CVD risk factors such as reducing hypertension, cholesterol, triglycerides, low-density lipoprotein (LDL) and increasing high-density lipoprotein (HDL) in animal models. This potentially makes KV a good medicinal (therapeutic) target for the management of cardiovascular diseases in humans. (11)
More clinical research is needed to validate this potential.
The compound Kolaviron in bitter kola has been the subject of research for decades. A 2013 study aimed at determining the effect of bitter kola on diabetic rats showed an increase in insulin levels which lowered their sugar levels, hinting at the possibility of bitter kola as an effective antidiabetic (12, 13).
At the moment, there are no scientific studies that assign any side effects to eating bitter kola. However, you should not eat bitter kola if you're allergic to nuts.
If you are on medications, consult with your doctor first to know if bitter kola is safe for you to eat.
Even though research is still in its early stage, bitter kola has many potential health benefits. Although it could be a natural addition to your diet, it's advisable to talk with your doctor on an appropriate amount of bitter kola to eat and if there'll be possible interactions with any medications that you are taking.
1. World Health Organisation. [Internet. August 2023]. Traditional Medicine Q & A. Available from here. Accessed June 1, 2024.
2. Odebunmi, E. O., Oluwaniyi, O. O., Awolola, G.V., Adediji, O. D. [Internet, December, 2008]. Proximate and nutritional composition of kola nut (Cola nitida), bitter cola (Garcinia cola) and alligator pepper (Afromomum melegueta). Afr. J. Biotech. 2009, 8(2) DOI:10.4314/ajb.v8i2.59797. Available from here.
3. Oluwatosin A, Tolulope A, Ayokulehin K, Patricia O, Aderemi K, Catherine F, Olusegun A. Antimalarial potential of kolaviron, a biflavonoid from Garcinia kola seeds, against Plasmodium berghei infection in Swiss albino mice. Asian Pac J Trop Med. 2014 Feb;7(2):97-104. doi: 10.1016/S1995-7645(14)60003-1. Available from here.
4. Adegboye MF, Akinpelu DA, Okoh AI. The bioactive and phytochemical properties of Garcinia kola (Heckel) seed extract on some pathogens. African Journal of Biotechnology. 2008, Vol. 7 (21), pp. 3934-3938. Available from here.
5. Amalu PC, Chukwuezi FO, Ugwu OP, [Internet, January 2014]. Antimicrobial Effects of Bitter Kola (Garcinia Kola) Nut on Staphylococcus Aureus, Eschererichia Coli and Candida Albicans. IOSR Journal of Dental and Medical Sciences 2014, 13(4):29-32 DOI:10.9790/0853-13452932. Available from here.
6. Djague F, Lunga PK., Toghueo KR., Melogmo DY, Fekam BF. Garcinia kola (Heckel) and Alchornea cordifolia from Cameroon possess potential antisalmonellal and antioxidant properties. PLoS One. 2020 Aug 4;15(8):e0237076. doi: 10.1371/journal.pone.0237076. Available from here..
7. Tauchen J, Frankova A, Manourova A, Valterova I, Lojka B, Leuner O. Garcinia kola: a critical review on chemistry and pharmacology of an important West African medicinal plant. Phytochem Rev. 2023, 23:1-47. doi: 10.1007/s11101-023-09869-w. Available from here.
8. Farombi EO, Shrotriya S, Surh YJ. Kolaviron inhibits dimethyl nitrosamine-induced liver injury by suppressing COX-2 and iNOS expression via NF-kappaB and AP-1. Life Sci. 2009 Jan 30;84(5-6):149-55. doi: 10.1016/j.lfs.2008.11.012. Available from here.
9. Manourova A, Leuner O, Tchoundjeu Z, Van Damme P, Verner V, P?ibyl O, Lojka B. Medicinal Potential, Utilization and Domestication Status of Bitter Kola (Garcinia kola Heckel) in West and Central Africa. Forests. 2019; 10(2):124. https://doi.org/10.3390/f10020124. Available from here.
10. Yakubu MT, Quadri AL. Garcinia kola seeds: is the aqueous extract a true aphrodisiac in male Wistar rats? Afr J Tradit Complement Altern Med. 2012 Jul 1;9(4):530-5. doi: 10.4314/ajtcam.v9i4.9. Available from here.
11. Olatoye FJ, Akindele AJ, Awodele O. The role of Kolaviron, a bioflavonoid from Garcinia kola, in the management of cardiovascular diseases: A systematic review. Heliyon. 2024 Feb 29;10(5):e27333. doi: 10.1016/j.heliyon.2024.e27333. Available from here.
12. Ayepola OR, Chegou NN, Brooks NL, Oguntibeju OO. Kolaviron, a Garcinia biflavonoid complex ameliorates hyperglycemia-mediated hepatic injury in rats via suppression of inflammatory responses. BMC Complement Altern Med. 2013 Dec 20;13:363. doi: 10.1186/1472-6882-13-363. Available from here.
13. Ezuruike UF, Prieto JM. The use of plants in the traditional management of diabetes in Nigeria: pharmacological and toxicological considerations. J Ethnopharmacol. 2014 Sep 11;155(2):857-924. doi: 10.1016/j.jep.2014.05.055. Available from here.
Published: June 10, 2024
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