It is naturally enclosed in a small spherical shell, but its teeny size does not limit its potency in any way, as researches continue to validate the efficacy of the African walnut as a fertility booster, immunity booster, as well as containing antiviral and inflammatory agents.
In the most recent study, Dada and Aguda, in the Journal of Aquatic Sciences, highlighted the fertility-aiding ability of the phytochemicals found in the black-shelled nut. Findings in the study titled, “Dietary effects of African walnut (Tetracarpidium conophorum) on the reproductive indices in male African catfish (Clarias gariepinus) broodstock, showed that supplementation of African walnut seed powder resulted in improved reproductive performance of male African catfish.
This indeed is a promising window of opportunity for health researchers and practitioners to conduct similar studies on humans with the prospect of curbing the rampant cases of infertility with the natural panacea in this nutrition powerhouse – especially as this is the season of the natural snack.
Another study conducted by researchers from the Department of Applied Biochemistry, Nnamdi Azikiwe University, Awka, Nigeria, suggested that the African walnut is an excellent food material with the potential of combating nutritional insecurity in rural communities where they are found. The research, titled: “Comparative proximate analyses of raw and cooked Tetracarpidium conophorum (African walnut)” showed that the nut is an interesting source of nutrient, being rich in fat with moderate values of crude protein and carbohydrate; while the ash and fibre content was shown to be very low. This explains why it is capable of warding off various viral infections and diseases.
The African walnut, scientifically known as Tetracarpidium conophorum (T. conophorum), belongs to the family Euphorbiaceas. It is a woody perennial climber found in the forest regions of Africa and India. African walnut has a long history as food plant and is grown by peasant farmers across West African rain forest. The climber bears capsules which are greenish in colour when young and greenish yellow when fully ripe. The walnut kernel consists of two bumpy lobes that look like abstract butterflies. The lobes are off white in colour and covered by a thin, light brown skin.
They are particularly attached to each other, while the kernel is enclosed in round or oblong shells that are brown or black in colour and they are hard. They contain four shelled seeds. The seeds take four to six months to mature and are found in the local markets between the months of June and September.
Conophorum plant is cultivated principally for the nuts which are cooked and consumed as snacks. The cooked nuts, containing the edible seeds, are common articles of trade in Nigeria. A bitter taste is usually felt upon drinking water immediately after eating the nuts. This is attributed to the presence of chemical substances such as alkaloids.
Nutritional content of walnut
According to scientists from the Department of Applied Biochemistry, Nnamdi Azikiwe University, Awka, Nigeria, the proximate compositions of raw and cooked nuts of T. conophorum were quantitatively evaluated, using the methods of the Association of Official Analytical Chemists (AOAC). They found that raw and cooked walnuts contain 2.0 per cent and 31.0 per cent moisture and 19.39 per cent and 15.90 per cent carbohydrate respectively.
They also contain crude protein of 23.01 per cent and 28.00 per cent, crude fat of 52.1 per cent and 21.1 per cent, crude fibre of 1.0 per cent and 2.0 per cent and ash of 2.0 per cent for raw and cooked walnut respectively. The energy value for raw and cooked walnut was 638.5 and 365.5 Kcal respectively.
Another report succinctly puts the nutritional value of the nut as follows: Omega-3 Fatty Acids 94.6 per cent; Copper 20.0 per cent; Manganese 42.5 per cent and Tryptophan 15.6 per cent.
Phytochemical analysis of the African walnut revealed a high preponderance of phytochemicals, especially saponins and flavonoids in both the dried and wet samples. The high level of antioxidants in this nut has also been severally reported. Many researchers have equally reported on the level of polyphenolic compounds, such as Ellagic and Gallic acids.
Other phenolic acids have been found in African walnuts, such as phenylacetic acid, a strong antisickling agent, protocatechoic acid, syringic, vanillic acid and caffeic acid. These phenolic acids found have been associated with astringency, discolouration and inhibition of some enzyme activity.
Other health benefits of walnut
- Prevents cardiovascular diseases: Omega-3 is a very important nutrient, which can prevent many diseases. Walnuts have a high concentration of these good fats, which lower the risks of cardiovascular diseases and promote better cognitive function.
- Anti-inflammatory: Walnut has anti-inflammatory properties that protect against asthma, rheumatoid arthritis and other skin diseases related to inflammation like psoriasis and eczema.
- Lowers cholesterol level: Walnuts can lower the cholesterol level, due to the nutrients it contains, like antioxidants, phenols, vitamin E, gallic acid and ellagic acid
- Immunity booster: Ellagic acid in walnuts is an antioxidant compound that boosts the immune system. In a study titled, ‘“Anti-microbial potential of extracts and fractions of the African walnut – Tetracarpidium conophorum”, published in African Journal of Biotechnology by E. O. Ajaiyeoba and D. A. Fadare of the Department of Pharmacognosy, Faculty of Pharmacy, University of Ibadan, it was found that extracts of the walnut plant are strong antibiotic.
- Helpful for the brain: Walnuts are great brain food. It is not only due to the wrinkled appearance of their shell that resembles the brain, but also due to the fact that they contain high levels of omega-3 fatty acids which plays an important role in the process of important nutrients entering the brain cells, and the exit of waste cells. Nearly 60 per cent of our brain is structural fats which are primarily omega-3 fatty acids.
- Sound sleep: Melatonin which is a powerful antioxidant and also induces a good night’s sleep, is present in walnuts in the bio-available form. Hence having a handful of walnuts before going off to bed helps in getting a sound sleep.
- Anti-aging agents: Most nuts are good for the skin. Benefits of walnuts for skin are due to the antioxidants they contain. As nuts contain vitamins A and E, they protect the skin against free radical damage, thus preventing the signs of aging. Also, the good fats which are omega-3 in walnuts help to maintain a nourished and smooth complexion.
- Helps prevent cancer: A research carried out in the Department of Chemistry, Ladoke Akintola University, Ogbomosho, found that the high ascorbic acid content found in the walnut indicates that the plant can be used to prevent or at least minimise the formation of carcinogenic substances from dietary material.
- Fertility booster: In addition to latest findings on the fertility boosting potential of the nut, a study published by the Nigeria Natural Medicine Development Agency (NNMDA), noted that walnut seeds are used in the treatment of fibroid. It also indicated that chewing the walnut improves sperm count in men.
Dada and Aguda 2015 Journal of Aquatic Sciences 30(1A): 107-118 Dietary effects of African walnut (Tetracarpidium conophorum) on the reproductive indices in male African catfish (Clarias gariepinus) broodstockPhytochemical and nutrient evaluation of Tetracarpidium Conophorum (Nigerian walnut)root. P.B.Ayoola, A. Adeyeye, O.O.Onawumi2 & O.O.P. Faboya
Department of Science Laboratory Technology, Ladoke Akintola University of Technology,P.M.B.4000, Ogbomoso,Oyo State, Nigeria.2Department of Chemistry, Ladoke Akintola University of Technology, P.M.B.4000,Ogbomoso,Oyo State, Nigeria.
Phytochemical and biochemical compositions of African Walnut ( Tetracarpidium conophorum) ®Nwaoguikpe R N1, Ujowundu CO1, Wesley. Department of Biochemistry, Federal University of Technology, P.M.B. 1526,Owerri,Imo State,Nigeria. Journal of Pharmaceutical and Biomedical Sciences
Comparative Proximate Analyses of Raw and Cooked Tetracarpidium conophorum (African Walnut) *Udedi, S.C., Ani, O.N., Anajekwu, B.N., Igwilo,I.O., Ononamadu,C.J., Adindu, C.S. and Okafor, U.M.Department of Applied Biochemistry, Nnamdi Azikiwe University, Awka, Nigeria.