Ethnobotanical survey of West-African vegetable food in the Netherlands Britt Boogmans supervised by Tinde van Andel NHN, Leiden University

Introduction Following migration, the majority of ethnic groups living in Europe alter their eating habits (Church et al. 2005) combining parts of their traditional diet with some of the less healthy elements of the Western diet For example, Turkish migrants in Denmark replace vegetables, fruit and yoghurt with syrups and ice cream, thus consuming less dietary fiber and vitamin C, and more protein, saturated fat and sucrose (Gilbert & Khokhar 2008). Changing diets and more sedentary lifestyles of migrated ethnic groups have resulted in major health concerns such as diabetes, obesity, hypertension and cardiovascular disease. (Gilbert & Khokhar 2008; Mennen et al. 2007) For some ethnic groups, however, traditional food habits are an important part of their cultural identity, and maintaining the diet is key priority, but traditional food items are not always available. Some changes in dietary habits result directly from the lack of availability or the high price of imported traditional foodstuffs in the host country (Gilbert & Khokhar 2008, Renzaho & Burns 2006). Several traditional foods and spices are also believed to have healing properties. In a study among South Asians in the UK, almost all vegetables were considered to have medicinal value. For example Momordica charantia was frequently reported to have anti-diabetic properties (Pieroni et al. 2007). Surinamese migrants living in the Netherlands consume several tropical vegetables and fruits for their medicinal properties, such as Solanum macrocarpon and Momordica charantia to prevent symptoms of diabetes (Van Andel & Westers 2010). In order to give culturally appropriate dietary advice, health practitioners need to be aware of their patients’ perception of food, health and medicine. British Bangladeshi diagnosed with diabetes mellitus type II, for instance, classified their food not by its nutrient content, as their doctors did, but by their own system of two dimensions: weak versus strong and easily digestible or indigestible (Chowdury et al. 2000). Diabetic Afro-Caribbean women we found to have their own cultural beliefs about diabetes, including the belief that certain vegetables such as Momordica charantia and prayer could cure diabetes (Smith, 2012). Ghanaian migrants in the UK reported that following migration, the consumption of tropical root crops, traditional vegetables, fish and fruit decreased and were replaced with potato starch, chicken, rice, bread and beef. Such changes decrease vitamin C intake and increase saturated fat percentages in the diet. Furthermore, it might result in a higher risk of diabetes type II due to the higher glycemic index of the diet (Saleh & Amanatidis 2002). Previous studies on migrants’ diets focused mainly on the nutritional value of foodstuffs (Mennen et al. 2007, Saleh & Amanatidis 2002, Agyemang et al. 2009), but little is known about which specific tropical fruits and vegetables are available to and consumed by these migrant communities. Nutritional value alone does not take into account the numerous plant metabolites and the effect they can have on the

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body, including the nutrient uptake (Akwaowo et al. 2000). Information on vegetable and fruit consumption for health promotion and disease prevention among West-African migrants might allow for a better understanding about the relation between traditional food, changing diets, nutrient intake and health. Some 20,000 Ghanaians live in the Netherlands, the majority in the Southeast of Amsterdam. Dutch-Ghanaians have a significantly higher prevalence of overweight and obesity than citizens of major cities in Ghana (Saleh & Amanatidis 2002). However, we know little about the diet of African migrants in the Netherlands, nor on their use of traditional food items to prevent or fight diseases prevalent among this group, such as cardio-vascular problems, obesity, high blood pressure and diabetes. Therefore we conducted a pilot study among West Africans in Amsterdam and The Hague to find out whether traditional foodstuffs also played a medicinal role. This study aimed to inventorize traditional fruits, spices and vegetables sold in Ghanaian or other WestAfrican shops and/or consumed by African migrants for medicinal purposes. We hypothesized that African foodstuffs were not only consumed for their taste or nutrient content, but also for health promotion, disease prevention and cure, as was the case for Surinamese migrants in the same Dutch cities (Van Andel and Westers, 2010) and South Asian immigrants in the UK (Pieroni et al. 2007). Traditional healing practices are often maintained by ethnic groups after migration (Van Andel & Westers 2010, Van Andel 2007, Pieroni et al. 2008, Pieroni et al. 2005), and beliefs about medicinal food among West Africans may differ greatly from the nutritionist point of view (Chowdury et al. 2000). Knowledge on the use of African foodstuffs to prevent and cure diseases can help to develop appropriate health and diet education for these migrant groups.

Research questions 1) Which traditional African fruits and vegetables are preferred by West-African immigrants in the Netherlands? 2) Do West-Africans eat certain traditional foods to promote their health, prevent or cure diseases? 3) Are some traditional African foodstuffs believed to prevent or cure diabetes, high blood pressure, obesity or cardiovascular problems?

Methodology We conducted an ethnobotanical inventory in West-African shops and market stalls in Amsterdam Southeast and The Hague. We carried out semi-structured interviews, with botanical collections to back up the vernacular names of the plants that respondents mentioned in the interviews. First, suitable shops and market stalls were located by visiting Amsterdam Southeast and by asking by passers for African shops and markets. Informants were recruited on a voluntary basis in and near these shops and stalls. Some informants took us to shops and market stalls we had not discovered before. Before the interview respondents were briefly informed about the aim of the research and how their personal information would be used and published. If they decided to participate, they were asked to supply some demographic information, to list their favorite African vegetables and fruits and if they knew any vegetables or fruits that could prevent or cure disease. In the last part of the questionnaire, they were asked whether they knew specific vegetables or fruits that could cure or help symptoms of diabetes, high blood pressure, obesity and cardiovascular problems. If they could not name plants for these diseases, the interviewer would ask if they were familiar with the disease, to check whether misunderstanding of a medical

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term like diabetes could be the reason for not answering the question. The complete interview can be found in Appendix 1 and the standard form used for botanical collections in Appendix 2. Plant parts were processed into botanical vouchers and identified at the Wageningen branch of the National Herbarium of the Netherlands (WAG). These vouchers served to connect the vernacular name of the vegetable with the scientific collection. In some cases, we germinated seeds and planted tubers to produce leafs or flowers to facilitate identification. Seedlings were grown on potting soil in a herbarium office room. Four plants of two different species were sent to the Amsterdam Botanic Garden for further propagation. For some of the plants mentioned by the respondents, especially for the fruits, no material was available for sale in the shops. Participants were then asked to describe the plant in detail, and this description was used in combination with the vernacular name and local flora’s to identify the particular species. Freelisting exercises were carried out to rank people’s preference for African vegetables and fruits. We calculated Smith’s salience for each species. This was done by first calculating the salience of the items in each interview by dividing the inverted rank by the total number of species listed in the interview. Inverting the rank would mean giving the lowest rank number one, and the second lowest number two, etcetera, ending with the highest rank equal to the number of items in the list (Puri 2011). For example, for a plant that was named second in a list with 4 items, the inverted number would be 3, and divided by the number of items listed (4) the salience would be 0,75. In one case, an informant named two species at the same time. This was the Ghanaian vegetable komususa, which can be either the large type (Solanum rudepannum) or the small and bitter type (S. anguivi). When the researcher asked which type of komususa the informant meant, she answered ‘both types’. In this case both Solanum species were given the same rank. To calculate the Smith’s salience, the average salience of a species over all the interviews was taken. Salience values were zero when plant species was not mentioned in an interview. We also calculated the citation frequency of the different plants species (the percentage of all respondents mentioning this species) in order to estimate their importance.

Results Characteristics of the respondent group We interviewed 15 West-African shopkeepers, market vendors and customers and one Surinamese shopkeeper, who said that the majority of his customers were African. He was asked to answer the questions from the perspective of his customers. Most of the respondents were born in Ghana (43,7%), followed by Nigeria (25%) Sierra Leone (12,5%), the Netherlands (6,3%), Niger(6,3%), and Surinam (6,3%). Three quarter of the respondents were male, 25% were female. Age was between 19 and 58 years, with a mean of 35,6 years. Length of stay in the Netherlands ranged between 2 weeks and 38 years, on average 15,5 years. We compared the composition of our pilot group to the information from the Dutch national statistics (CBS 2012). The percentage living in the Netherlands is calculated compared to the total population of these four groups in the Netherlands. As we show in table 1, the actual composition and the composition of the respondent group is quite similar. However, this comparison does not include the other West-African nationalities present in the Netherlands.

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Table 1: Comparison between CBS statistics and pilot group composition Country of origin Ghana Nigeria Sierra Leone Niger Total

Persons Percentage Percentage living in the living in NL of Netherlands respondents 21376 55,53 53,33 10676 27,7 26,66 6030 15,66 13,33 407 1,05 6,666 38489 100 100

Botanical diversity of species mentioned during interviews In total, 46 botanical collections were made, of which 39 were identified to the species level, 4 to the genus level and 3 only to a family level. We encountered 33 to 35 different species, in 23 different families. See table 1 for a complete table of the collected material and species named in interviews including vernacular names and uses. We also collected several species that were not explicitly mentioned during the interviews, but sold in the shops where we interviewed our participants, for example Treculia africana.

Freelisting analysis Smith’s saliences and citation frequencies for all species encountered are listed in figure 1. The most frequently mentioned vegetables were Solanum aethiopicum, Xanthosoma sagittifolia and Abelmoschus esculentus. The most salient fruits were Citrus sinensis, Mangifera indica and Persea americana. Some of the popular vegetables are also the most salient in the ‘medicinal domain’, such as Solanum aethiopicum and Telfairia occidentalis. Several preferred fruits were also considered medicinal, like Psidium guajava, but these could also refer to different plant organs from the same species, such as mango leaves (Mangifera indica) or the avocado fruit peel (Persea americana). All of the nine spices encountered had medicinal properties, usually administered in a tea, more concentrated then when used in a dish. Another notable outcome is the recommendation for diabetics to eat the green plantain (Musa x paradisiaca) instead of the yellow and ripe plantain, because the ripe fruit was said to contain more sugar. Of the 30 vegetables named, 22 had medicinal value, of the 16 fruits, 12 were medicinal. All eleven spices were considered medicinal. Of the twelve other foodstuffs, seven were considered medicinal.

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Figure 1: Smith’s Salience values for the freelisting analysis of preferred African vegetables among the 16 respondents.

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Availability Many of the traditional West African foodstuffs are generally available on markets in Amsterdam Southeast and The Hague, either fresh, frozen or dried. Shipments of fresh material arrive weekly. Traditional fresh sweet fruits are hardly sold, they are said to be too expensive in the Netherlands. Only fruits which are considered vegetables, like Solanum aethiopicum, are imported, possibly because they have longer shelf life. Some products that are not sold on a daily base can be ordered for. Disease awareness In order to assess the disease awareness among West-African migrants, the results obtained from the Surinamese shopkeeper were left out. Most of the respondents named one or more vegetables or fruits that in their opinion could prevent or treat symptoms of diabetes (66,6% and 16 species) and high blood pressure (66,6% and 10 species). This was less for heart problems (40% and 9 species) and lowest for obesity (33,3% and 3 species). If the knowledge of medicinal plants represents awareness of a specific condition, West-African migrants are most aware of diabetes, followed by high blood pressure, heart problems and the least of obesity. Respondents who did not report any plants for diabetes, high blood pressure, obesity or heart problems all said they recognized the symptoms of the four health problems, which also indicates their awareness of these diseases. It must be noted, however, that this represents reported knowledge about a disease. We did not test people’s actual knowledge. Quite notable is that respondents frequently reported a short cooking time (5-10 minutes) for leaf vegetables and herbs such as Xanthosoma sagittifolia, Telfairia occidentalis, Ocimum lamiifolium and Ocimum basilicum in order to keep the taste. These were either sold fresh or frozen.

Discussion Representativeness of respondent group If we compare the frequency of countries of birth in our respondent group and compare it to the immigrant statistics (CBS 2012), the ratio between the different countries of birth seems quite accurate (see table 1). However, other West-African countries of which immigrants live in the Netherlands (Mauritania, Benin, Burkina Faso, Gambia, Guinea, Guinea-Bissau, Cote d’Ivoire, Cape Verde, Liberia, Mali, Senegal and Togo), were not represented at all, while together they do represent half of the West African immigrants in the Netherlands. (CBS 2011). Although the response group is too small to allow proper statistic analysis, we have some indication that favorite vegetables are influenced by the country of birth of the informant. For example Xanthosoma saggittifolium was cited 5 times, by 4 informants born in Ghana, and one born in the Netherlands with Ghanaian parents. This implicates that a different composition of the respondent group regarding country of birth might change the cited vegetables, and thus their salience. For future research we recommend a larger group of informants, to show the variety in the diet of West-African people depending on their birth countries and ethnicity. 8

Evidence for medicinal properties of African food plants For some of the vegetables and spices, clinical research is done about the effects and active compounds present. The Ghanaian spice prekèsè (Tetrapleura tetraptera) was used by our informants for high blood pressure, heart problems and diabetes. Clinical research proves that the fruit indeed has hypotensive and hypoglycemic effects, and is also antiinflammatory and anticonvulsant, but toxic in high doses (Ojewole & Adesina 1983, Ojewole & Adewinmi 2004, Nwaiwu & Akah 1986). Also, some traditional spices from Cameroon were found to be bactericidal, such as Piper guineense, Monodora sp. and Xylopia aethiopica (Tekwu et al. 2012), which we also encountered being sold in the Netherlands. Respondents frequently reported a short cooking time (5-10 minutes) for leaf vegetables and herbs such as Xanthosoma sagittifolia, Telfairia occidentalis, Ocimum lamiifolium and Ocimum basilicum. Cooking leaf vegetables shorter can be beneficial because it maintains most of the vitamins and nutrients. On the other hand cooking shorter might not be enough to eliminate the plants antinutrients and other defensive chemicals. For example X. sagittifolia contains several oxalates, which reduces nutrient uptake. Oxalates can form calcium oxalate crystals in the body, causing kidney stones (Massey et al. 1993) and blistering of the skin and are toxic in high doses. Cooking the leaves can significantly reduce the oxalates present (Lumu & Katongole). Whether a short cooking time is beneficial or not depends on the plant species, breed and maturity of the leaf.

We suggest more research is done into both the effects of the West-African foodstuffs used for diabetes, high blood pressure, obesity and heart problems as well as a larger scale research about the dual use of traditional vegetables as food and medicine by WestAfrican migrants. This combination of research allows us to develop better culturally sensitive health education programs. For example West-African diabetic patients could be recommended to replace the potato starch in their diet with plantains, which have a lower glycemic index (Bahado-Singh et al. 2006, Ramdath et al. 2004)Because plantains are already part of the West-African diet, it is much more likely for the patients to adopt this change then if a culturally inappropriate alternative, such as pasta, is given.

Cultural change We also have several indications that plant use is not a static tradition, but is constantly influenced by the interaction and exchange of ethnobotanical information with other migrant groups. One of our Ghanaian informants said she preferred a Nigerian leaf vegetable called ugu (Telfairia occidentalis) and that this could also help you stay healthy or prevent disease. Apparantly there is an exchange of knowledge between people from different nationalities and ethnicities. The West-African population in the Netherlands is relatively small and mainly concentrated in Amsterdam and The Hague. We think the contact between West-Africans from different nationality is more intensive in the Netherlands then in West-Africa. Therefore the respondent might have learned to use this vegetable in the Netherlands. 9

The Surinamese shopkeeper said that his African clients sometimes came to him for advice about healthy vegetables. Another example of changing plant knowledge is the use of the neem tree (Azadirachta indica), mentioned by our respondents as a vegetable and medicine. Neem originates from India and is used medicinally there. It was introduced into Africa in the 19th century and seems to have been incorporated into the West African pharmacopeia. These examples show that plant use changes constantly under the influence of other cultures and changes in the environment. In a time of increasing globalization it is interesting to know how the traditions of plant use are influenced by migration and mixing of cultures and whether this plant use can be promoted to improve the health of migrant groups.

Conclusions We show that Solanum aethiopicum, Xanthosoma sagittifolia and Abelmoschus esculentus are the most preferred vegetables and Citrus sinensis, Mangifera indica and Persea americana the most preferred fruits amongst our pilot group of 16 respondents. Although the cost of

importing traditional African vegetables is quite high, West-African migrants living in Southeast Amsterdam have access to many traditional vegetable and spice species. Most of the preferred vegetables and some of the fruits listed by our pilot group are also considered to have a medicinal value. This indicates there is no clear distinction between food use and medicinal use in the plant uses of West-African migrants.West-Africans do eat certain traditional foods to improve their health. West-African migrants also use healing foodstuffs against diabetes, high blood pressure, heart disease and obesity. From the amount of vegetables and fruits used for these diseases and the number of respondents knowing such foodstuffs, we conclude there is reasonable awareness of diabetes, moderate awareness of high blood pressure and heart problems but that obesity is considered less of a health risk. This corresponds to the African beauty ideal that prefers higher body mass index as a sign of wealth and health, a general perception that can reduce obesity awareness (Renzaho 2004). It is important for healthcare professionals, especially in areas where an important part of the population is of West-African origin, such as Amsterdam Southeast, to have insight on the home remedies these people use and the way they perceive the relationship between food and health. Therefore more research is needed into the medicinal use of traditional African foodstuff and the clinical effects of these products.

Additional material: Table 2: Plant species mentioned by the 15 respondents. Voucher material is listed with their collection numbers.

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Mennen, L.I. et al. Habitual diet in four populations of African origin: a descriptive paper on nutrient intakes in rural and urban Cameroon, Jamaica and Caribbean migrants in Britain. Public Health Nutrition 4, 765 (2007). Nwaiwu, J. I. & Akah, P. A. Anticonvulsant activity of the volatile oil from the fruit of Tetrapleura tetraptera. Journal of Ethnopharmacology 18, 103-107 (1986) Pieroni, A., Muenz, H., Akbulut, M., Başer, K.H.C. & Durmuşkahya, C. Traditional phytotherapy and trans-cultural pharmacy among Turkish migrants living in Cologne, Germany. Journal of ethnopharmacology 102, 69-88 (2005). Pieroni, A., Houlihan, L., Ansari, N., Hussain, B. & Aslam, S. Medicinal perceptions of vegetables traditionally consumed by South-Asian migrants living in Bradford, Northern England. Journal of ethnopharmacology 113, 100-10 (2007). Pieroni, A., Sheikh, Q.-Z., Ali, W. & Torry, B. Traditional medicines used by Pakistani migrants from Mirpur living in Bradford, Northern England. Complementary therapies in medicine 16, 81-86 (2008). Puri, R. K. Documenting Local Environmental Knowledge and Change. In Conducting Research in Conservation: A Social Science Perspective, Newing, H. (Ed) London: Routledge. (2010) Ramdath D.D., Isaacs R.L.C., Teelucksingh S., Wolever T.M.S. Glycaemic index of selected staples commonly eaten in the Caribbean and the effects of boiling v. crushing. Br J Nutr 91: 971-7 (2004) Renzaho, A. M. N. Fat, rich and beautiful: changing socio-cultural paradigms associated with obesity risk, nutritional status and refugee children from sub-Saharan Africa. Health & Place 10, 105-113 (2004). Renzaho, A.M.N. & Burns, C. Post-migration food habits of sub-Saharan African migrants in Victoria: A cross-sectional study. Nutrition & Dietetics 63, 91-102 (2006). Saleh, A. & Amanatidis, S. Ecology of Food and Nutrition The effect of migration on dietary intake , type 2 diabetes and obesity : The Ghanaian health and nutrition analysis in Sydney , Australia ( Ghanaisa ). Ecology of Food and Nutrition 41, 255-270 (2002). Smith, C. A. S. Living with sugar: Influence of Cultural Beliefs on Type 2 Diabetes SelfManagement of English-Speaking Afro-Carribean Women Journal of Immigrant and Minority Health 14, 640-647 (2012).

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Tekwu, E. M., Askun, T., Kuete, V., Nkengfack, A. E., Nyasse, B., Etoa, F. X. & Penlap Beng, V. Antibacterial activity of selected Cameroonian dietary spices ethnomedically used against strains of Mycobacterium tuberculosis. Journal of Ethnopharmacology 142, 374-382 (2012) Ojewole, J. A. O. & Adesina, S. K. Mechanisms of the Hypotensive Effect of Scopoletin Isolated from the Fruit of Tetrapleura tetraptera. Journal of Medicinal Plant Research 49, 46-50 (1983) Ojewole, J. O. A. & Adewunmi, C. O. Anti-inflammatory and hypoglycaemic effects of Tetrapleura tetraptera (Taub) [Fabaceae] fruit aqueous extract in rats. Journal of Ethnopharmacology 95, 177-182 (2004)

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Appendix 1: Interview form INTERVIEW AFRICAN FRUIT AND VEGETABLES Name interviewer: Location: (address)

Date:

Male/Female

Age…………………

Name: (not necessary)……………………………………………. Country of Birth:………………………………………………. Nationality………………………… Length of stay in the Netherlands:………………………………………………… Preferred African vegetables (4) 1. 2. 3. 4. Preferred African fruits (4) 1. 2. 3. 4. Do people use certain vegetables or fruits to stay healthy or prevent disease: 1. 2. 3. 4. Are there certain vegetables or fruits that people use to prevent / help fight symptoms of diabetes (too much sugar in blood) high blood pressure obesity (if people are too fat) cardiovascular problems (heart problems. stroke)

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Appendix 2: Plant collection form For every plant collected Date:

Collector:

Informant:

BB Nr.

Locality: city + address ………………………………………………………………………………

Local name……………………………………………………………Language……………………..

Scientific Name…………………………………………………………Family……………………….

Country of plant origin:…………………………………………………………………..

Description of plant (growth form, colors, flowers, fruits, seeds)

Use: (food / medicine, preparation methods (recipe), name dish, taste , diseases,

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