Dietary restrictions in healing among speakers of Iquito, an endangered language of the Peruvian Amazon

Dietary restrictions accompanying the healing process have been reported from geographically widespread locations, including Africa [1, 2], Europe [3], North America [1], Southeast Asia [4, 5], and South America [6‐8]. The connection between diet and medicine forms an important part of the classical and modern humoral traditions of India, China, ancient Greece and medieval Europe [9‐12]. Some authors [13, 14] have also pointed out the importance of dietary context for understanding the physiological effects of medicinal plants from a biomedical perspective. A number of recent review articles [15‐17] have also treated dietary taboos in a broader social context.

In the Amazonian case, the ethnomedical literature [18‐23] has tended to discuss dietary restrictions in the context of spiritual traditions related to ayahuasca and other psychoactive plants, as well as their role in learning how to heal in that tradition [19, 21]. However, the healing systems of many Amazonian societies [24‐27] rely on cures of both a physical and spiritual nature. Attitudes toward medicinal plants also reflect this duality. On one hand, plants are thought to have physical effects on the body. On the other, they are believed to possess spirits that can actively participate in the healing process. Physical cures are often common knowledge that any adult possesses, while spiritual cures tend to be the province of specialists. Lenaerts argues, based on his work with the Ashéninka and other Amazonian societies [25, 28], that these two forms of healing are not simply parallel systems coexisting in the same place. Rather, the spiritual level is the one of real power and efficacy, while the physical is merely useful for relieving symptoms. Other authors [8, 29, 30] have made similar observations in other Amazonian societies.

This paper presents the results of research on the relationship between illness explanatory models (EMs) [31] and corresponding restrictions on diet and activities for speakers of Iquito, a critically endangered [32] language of the Peruvian Amazon. The explanatory model is a framework for describing a cognitive model of how illness works in terms of five components: 1) etiology, 2) onset of symptoms, 3) pathophysiology, 4) prognosis and 5) treatment [31]. This framework allows for a detailed examination of the rationales for dietary restrictions within the logic of a given ethnomedical system. The first hypothesis of this research is: H1 - Each restriction will correlate in a systematic way with one or more elements of the illness explanatory models. In other words, one might find that fish with sharp teeth are never eaten for illnesses involving internal bleeding, or that patients given enemas must always avoid rain and cold.

The Iquito are no exception to the general Amazonian trend of plurality of medical reasoning, making reference to spiritual, emotional, humoral and contamination-related illness etiologies, among others. However, some of these etiologies appear to have been adopted fairly recently. Study participants said that their ancestors attributed spiritual causes to any illness that did not have an obvious physical cause. Taking that claim as a cue, and following the observation of various authors [25, 28‐30] in favor of the primacy of spiritual over naturalistic healing modalities in other Amazonian societies, the second research hypothesis is: H2 - Illnesses whose explanatory models have personalistic elements will show a greater number and variety of restrictions than those based on naturalistic reasoning. For example, one would expect to find greater restrictions when a plant spirit or witchcraft is believed to be involved, than for cures based on humoral reasoning.

Iquito is a language of the Zaparoan family, spoken by roughly twenty people, living in two villages in the Alto Nanay region of the north-eastern Amazon (Figure 1). According to early Spanish colonial reports, the language once extended over the area between the Tigre, Mazán and Amazonas rivers. The Iquito moved away from the major rivers from the 17^th to the 19^th centuries to avoid mission settlements and slave raids. By the early 20^th century, they started to form larger settlements downriver, including the village of San Antonio, on the Pintoyacu river, where this study took place [33, 34].

Although mestizo (mixed native and European) settlers arrived with the rubber boom in the 1920s [34], the Iquito were essentially monolingual through the 1930s. With the death of the Iquito curaca (traditional leader) in 1944, the patrones (rubber bosses) consolidated their power, controlling the native population with a system of debt peonage. The newcomers brought a very negative attitude toward the Iquito language and discouraged its use, sometimes with violent means. By the end of the 1950s, most adults were already bilingual in Spanish and many children did not learn Iquito at all [33].

Currently, none of the 20 or so speakers remaining is less than 50 years old. Negative feeling towards the language still exists, although it has diminished. In the last decade, linguists have been working on an Iquito-Spanish dictionary [35] and on bilingual educational materials. The research described in this paper is part of a larger project representing the first study of Iquito ethnobotany and will hopefully contribute in some modest way to recent efforts [33, 35‐37] to document the language.

Table 1 shows the 49 illness categories informants mentioned in the interviews. They cover a range of internal and external complaints as well as some magical conditions. A few local illness terms and culture-bound syndromes require explanation. Aquíraja (choque de aire in Spanish) involves diarrhea and vomiting and is thought to come from being struck by a strong wind carrying bad spirits or harmful environmental influences. Corazonada is a dangerously strong heartbeat that comes from arguing with one's spouse. Empacho is a digestive illness said to be caused by bad diet, involving intestinal swelling, headache, vomiting and diarrhea. Isíicu (sarna in Spanish) refers to a variety of skin infections. Informants recognized several types, including ácusana ('red') isíicu , characterized by red, itchy spots, musutina ('white') isíicu , involving white spots that are not painful, and s+ríca , which causes white, itchy patches [35]. Múcuaay+ itúuja - literally "rainbow burn" is a rash caused by exposure to a rainbow, the sun or mist. Pulsario is a worm that lives in the lower abdomen and grows bigger with emotional stress. Saladera involves persistent bad luck, especially in hunting. Sobreparto is an illness women may suffer after giving birth that involves diarrhea, body pain and fever. Tabardillo is a high fever caused by bathing too quickly after working in the sun.

As already noted, informants said the old Iquito attributed spiritual causes to any illness without an obvious physical origin. Infectious diseases in particular, such as measles and whooping cough were said to have a spirit like a person ( niatíja - literally "mother" in Iquito). When a wave of epidemics came with the first mestizo settlers of the 1920s, people said the spirits flew through the air like angels searching for people to infect. The Iquito were not unique in this regard, Chaumeil mentions a similar belief among the neighboring Yagua [29], as does Bellier [39] for the Maihuna. Another type of personalistic etiology involves witchcraft. Witches are said to attack by a variety of means, including causing an invisible phlegm-like substance to lodge in the victim's body, producing severe pain.

Currently, witchcraft is still taken seriously in San Antonio, but belief in illness spirits has fallen out of favor. Study participants were more inclined to invoke humoral explanations, including excessive temperature and aquíraja - "bad air or wind." These EMs are broadly similar to humoral theories of health found in many parts of Central and South America [11, 13]. Scholars have debated whether these ideas originated independently in the New World [40, 41], or were simply borrowed from the Spanish [11]. The illness category s'+m+siini - "rheumatism" is a good example of humoral reasoning. When a person is exposed to night air, rain, wind or frigid bath water, the cold can stay in the bones and joints, causing pain and discomfort. Heat from the sun or from cooked foods and beverages can cause ípanaca - 'fever,' and enter bodily organs, potentially causing them damage. Moving too rapidly from one temperature extreme to another can also be harmful. Some informants say kidney problems can arise from taking a cold bath too soon after working in the hot sun. The rapid change causes the blood to become viscous and not circulate properly, which also harms internal organs.

Study collaborators attributed some illnesses to bad water or food. Standing water is commonly associated with tan+'+ca - "malaria." It is considered harmful because animals defecate in it, or because it contains "microbios." The later term is ambiguous, as it is used for small visible organisms such as insect larvae as well as for microbes in the biomedical sense. Simple diarrhea (without blood or mucous) is blamed on eating greasy foods on an empty stomach, while intestinal parasites are said to come from consuming sweet fruits like ripe plantains and caimito (Pouteria caimito). The old Iquito took purges such as ácuta (Banisteriopsis caapi) and curarina (Potalia amara) often to cleanse impurities from the body, but such treatments have fallen out of use in recent times.

Some illnesses result from contamination of the blood. Healthy blood is considered key to maintaining overall good health. Lenaerts [25] has noted similar beliefs among the Ashéninka. One of the most common illnesses attributed to bad blood is pisáqui - "pus-filled boils." Contamination can come from eating the meat of certain animals like tapirs, whose blood is dark and considered to be dangerously strong. Blood-related illnesses and skin problems in general are also said to come from eating fish with spotted patterns. This is an example of sympathetic reasoning, whereby foods are thought to transfer particular qualities to people who eat them. Similarly, babies are susceptible to m+'+riaaca- "mouth sores," when a breastfeeding mother consumes spotted fish. Some people said biting flies and mosquitoes can contaminate the blood because they also bite dogs or wild animals such as snakes and transfer that foreign blood a person's body.

A few illness etiologies do not fit easily into any of the above categories. Getting dirt in an eye from running into spider webs in the forest causes carijáquica - "eye pain." Intestinal parasites are thought to infect people who walk barefoot, through the soles of the feet. Many informants noted that doctors told them malaria comes from mosquito bites, although some were skeptical about that explanation. Some illnesses have emotional causes, including the culturally bound syndromes corazonada and pulsario mentioned above.

Avoiding certain foods and activities is often a necessary part of the healing process for Iquito speakers of San Antonio. Informants used the Spanish term dietar or the Iquito siyan++ni - "to diet" to describe this process. All collaborators related examples of people who became more ill or died from failing to follow expected restrictions.

Three main reasons for restrictions were given: 1) some foods and activities can exacerbate an illness, 2) some methods of administration (i.e. steam baths or enemas) leave a patient susceptible to harm from hot or cold environmental influences, 3) some healing plants possess spirits that require the patient to avoid certain foods or activities. In the first category, the diet is explained in terms of the etiology and pathophysiology of the illness. In the second and third, the restrictions are required to avoid conflicting with the treatment itself.

The following section describes common classes of dietary restrictions mentioned for two or more illnesses. These are grouped into categories and presented in terms of illness explanatory models.

The first hypothesis, that each restriction will correlate in a systematic way with one or more elements of the illness explanatory models, is supported by the data. Seventeen distinct dietary restrictions were mentioned two or more times in the interviews. All correlate to some aspect of the illness EMs. Six (35%), (wind, heat, cold, bad blood, sweet foods and exertion) correspond to particular illness etiologies. Nine (53%), (spicy foods, heat, cold, toothed animals and fish, sex, soup, sweet foods, alcohol and exertion) correspond to specific illness pathophysiologies. Two (12%), (heat and cold), correspond to treatments administered as enemas or steam baths. Three prohibitions (18%), (oily foods, sour foods and pork) correspond only to the overall seriousness of an illness. Three restrictions (18%), (salt, manioc and isolation) are only found in cases of treatments involving powerful plant spirits.