Childhood asthma and dietary management among Singapore parents

Citation

Ling Ang, K. and Foo, S. (2001), "Childhood asthma and dietary management among Singapore parents", Nutrition & Food Science, Vol. 31 No. 6. https://doi.org/10.1108/nfs.2001.01731faf.001

Childhood asthma and dietary management among Singapore parents

Childhood asthma and dietary management among Singapore parents

Introduction

A study conducted in Singapore found the incidence of asthma among Singaporean children to be as high as one in five (Goh et’al., 1994). Such incidence rate was also reported in the UK (Speight et’al., 1983). They found that by the age of ten, at least 20 per cent of all children will, at some time or other, have had symptoms of underlying asthma. Asthma has also been found to be the most common chronic disease in children affecting 7 per cent to 10 per cent of preschool children in the USA (Peterson, 2000). This finding was also confirmed by the US Department of Health & Human Services which also found that asthma is the leading cause of school absenteeism (Ukens, 1999).

In asthma, the airway epithelium is often damaged. This reduces the efficiency of cilial actions and therefore contributes to the pooling of secretion within the lungs. Children's airway diameters are considerably smaller than in adults, so when there is a broncho-constriction, the resistance to airflow is inevitably higher. This often leads to hyperinflation in order to meet the increased oxygen demand (Lenny and Milner, 1983).

Careful epidemiological studies that have been repeated after an interval of 15-30 years have shown that there is an increase in both the prevalence and severity of asthma in many parts of the world (Roberts et’al., 1991). The reasons remain obscure, but many suspect that environmental factors are responsible for these changes. In fact, there are multifactorial causes of asthma. The common triggers of asthmatic symptoms in children are well established in many studies and include mainly those of:

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  bronchial viral infections;

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  pollution;

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  dust;

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  mites;

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  pollens;

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  stress; and

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  some food allergens, such as royal jelly (Berkovitch et’al., 1970; Wilson et’al., 1985; Steinman and Weinberg, 1986; Thien et’al., 1993; Bollock et’al., 1994).

Although asthmatic symptoms are usually temporary, the repetitive nature of the condition and the devastating effects it has particularly on children, warrant it to be better understood and properly managed. A literature search on a number of online databases, including ProQuest and Medline, recorded many studies on asthma but they were related to environmental triggers, social, genetic factors and drugs treatment. Others studies were related to food sensitivities such as food additives like colouring agents, preservatives, citric acid, and flavoring agents. Studies done at allergy clinics for treating asthmatic children found symptoms of asthma to be triggered by allergy to beef and cow's milk (Fuglsang et’al., 1994; Werfel et’al., 1997). Allergic diseases, particularly asthma, were also caused by the early introduction of certain foods (Lorente et’al., 1998).

However, few studies have so far been done on diet practises or restriction among parents of asthmatic children (Ford et’al., 1989; Dawson et’al., 1990). In Singapore, it is a rather common practice among parents of asthmatic children to restrict or abstain from certain foods and beverages. In addition, some parents have known to apply folklore remedies in an attempt to curb their children's asthma attacks. The major aims of this study are to determine the extent of dietary restriction management among these parents, their assessment of asthmatic triggers in food given to their children, and the application of folklore remedies. This paper will highlight these major findings. These findings would have important implications since inappropriate diet restriction or avoidance can lead to malnutrition and even affect children's growth (Labib et’al., 1989).

Methodology

A total of 39 randomly selected primary schools with school children ages ranging from seven to 12 were sampled. A survey questionnaire in three different languages, namely, English, Mandarin and Malay (see Appendix) was administered to parents of these randomly selected students of all levels. This was to cater to the different language backgrounds of the parents to assist them complete the questionnaire using their preferred language and to avoid or minimise misinterpretation of the questions.

Section A recorded the demographic data and Section B of the structured questionnaire is used to isolate the actual asthmatic cases among the respondents. Although, it remains impossible to reach a universal consensus on a precise definition for asthma condition (Scadding, 1983), the criteria for or diagnosis of asthma adopted in this study was based on the questionnaire used in the International Study of Asthma and Allergies in Childhood (ISAAC, 1992) that identified symptoms of persistent cough, wheezing and/or breathlessness.

Sections C of the questionnaire sought to establish the main triggers of asthma symptoms, the type of food and beverages that were believed to trigger asthma symptoms, detecting the presence of any confirmatory tests of these "triggers", the prevalence of dietary restrictions imposed by parents of asthmatic children in order to avoid asthmatic attacks and sources of information for such practises. This section also sought to identify if any supplements were given and the types of supplement and food given to their children in order to avoid asthma attacks and the sources of this information.

Section D of the questionnaire sought to elicit the existence of any traditional or folklore remedies used in managing asthma and the sources of such advise. This section also sought to find out how parents rate various asthma management approaches.

Section E established family history of asthma, breast-feeding and weaning practises.

Results and discussion

A total of 4,680 primary school children were surveyed. This produced a very good response of 93 per cent, with 4,352 returns. Demographic and social-economic distribution of respondents were representative of Singapore families, as shown in Table I. The statistical package for social science (SPSS) was used to analyse the returns and to generate statistics for the findings. The major findings from the survey are elaborated in the following sections.

Table I Demographic profile and social-economic categories of study population n = 4,352)

Table II summarises the main asthma triggers. This is in the order of infection, foods and drinks, changes in weather, exercise, pollution such as dust and smoke and fur/feather from animals. It is interesting to note that the prevalence of exercise-related symptom exacerbation is comparable to that previously reported by Goh et’al. (1994).

Table II Reported triggers of asthma attacks n = 4,352)

Infections

The most frequent trigger of asthma reported by this group of parents is infection. Infections are well-known to be the primary exacerbating factor in childhood asthma. This is particulary true with viruses and Mycoplasma pneumoniae (Berkovitch et al., 1970). Viral respiratory infections provoke wheezing in patients with existing asthma (Busse, 1991). Clinical evidence suggests that some patients develop asthma following an uncomplicated viral respiratory illness. There are also a number of studies showing that babies who have acute viral bronchiolitis will often have recurrent attacks of coughing and wheezing for the next three to five years (Webbs et’al., 1985). It has been calculated that about 20 per cent of all wheezing attacks in the first five years of life are the result of previous attacks of acute bronchiolitis (Milner, 1993).

Interestingly, food and beverages is the second most frequent trigger reported by this same group of parents. Over half (59 per cent, n = 1,228) of those surveyed reported different kinds of foods and drinks as exacerbators of asthma with the top ten exacerbators shown in Table III. This is a relatively much higher percentage compared to overseas' populations. Wilson et al. found this value to be 18.6 per cent among their sampled parents with asthmatic children in asthmatic clinics and hospitals in London (Wilson et al., 1985) while Ang found it be 19.7 per cent in a similar study conducted in central London (Ang, 1994). Reports of food related asthma has also been previously reported in Asian children, more so than non-Asian children (Wilson et’al., 1985).

Table III Reported foods and beverages as exacerbators of asthma

All 100 per cent (n = 1,226) of parents surveyed in this study reported that iced water and ice-cream provoked their children's asthma. The next common items reported were:

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  fizzy drinks (93 per cent, n = 1,143);

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  cold/chilled foods (79 per cent, n = 964);

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  fresh fruit juices (76 per cent, n = 928); and

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  fruits (69 per cent, n = 843).

The rest of foods/drinks reported, in order of decreasing frequency, were chocolates, food additives, sweets and sweet foods, nuts and milk/dairy products.

While Wilson et’al. (1982) have found that there is an increased bronchial responsiveness caused by ingestion of ice, however, this may not be the direct cause of asthma attacks. Likewise, in another of Wilson's studies (Wilson et’al., 1985), cola and other fizzy drinks increased sensitivity of the airways. However, exposure to only a single stimulant may not be sufficient to exacerbate the asthma. Added triggers may start the attack. Steinman and Weinberg (1986), who conducted a study on the effects of soft-drink preservatives on asthmatic children, had shown that it was not the beverage that caused the asthmatic symptoms, but rather the presence of additional stimuli, such as cold air or physical strain (exercise), as the airways and lungs become more sensitive with these beverages. This can be illustrated in the "asthma barrel" effect as shown in Figure 1. For example, a brief football game during school recess may not immediately trigger an asthma attack, but drinking from the cold water cooler and sitting under the fan to cool down, after the game, may start the asthma.

Figure 1 Asthma barrel effect

Diagnosis of food triggers

The major manifestations reported after ingestion of these foods and drinks include:

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  coughing (95 per cent, n = 1,105);

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  wheezing (57 per cent, n = 542); and

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  shortness of breath (27 per cent, n = 318).

The time of onset of reactions from the ingestion of foods or beverages was within a few minutes in only 8 per cent (n = 95) of subjects surveyed while over 27 per cent (n = 313) could not recall the interval. A toal of 35 per cent (n = 409) even reported reactions within a few days! This is rather interesting as allergic reactions would largely be of the hypersensitivity reaction and would classically manifest within minutes, whereas a delayed manifestation may indicate alternative mechanisms (Thien et’al., 1993). Although these reactions were reported to have been confirmed by family doctors in most of the cases (35 per cent, n = 411) or specialist doctors (13 per cent, n = 149), only 5 per cent of them had any confirmatory test done (e.g. skin prick test or blood allergy test).

Diet management

Almost 60 per cent (n = 1,210) of these parents of asthmatic children practise food restriction or avoidance, at some time, in the attempt to alleviate asthma symptoms. Of these, 16 per cent (n = 192) avoid certain foods and drinks totally and at all times; while 23 per cent (n = 278) allow these "trigger" foods and drinks when the child is fairly well symptomatically; and over 53 per cent (n = 648) abstain from these foods, except on special occasions such as birthdays.

This indicates that a fairly significant group of parents actually do exercise food avoidance or dietary alteration in their child because of asthma. Avoiding or restricting cold fizzy drinks, ice-cream or sweets, from the nutritional perspective, are not so much of a concern. What is most worrying are the fruits and fruit juices, which happen to be among the top five foods that they remove from their children's diet. Fruits and fruit juices are rich in vitamin C, which in many studies have been found to build-up resistance against transient respiratory diseases (which is one of the causes leading to asthma wheezing) (Bucca et’al., 1992). Removal of fruits from the diet may also result in a reduction in dietary fibre intake. It is not clear if these children are consuming and enjoying plenty of vegetables when fruits are removed from their diet.

Most of these parents practise such diet management out of their own experience and initiative (45 per cent, n = 548) or based on advice from friends and relatives (37 per cent, n = 443). Interestingly, 62 per cent (n = 751) reported that they do so under the advice of their doctors. It is understandable that parents are anxious and may be frustrated by the constant reliance on drugs in the management of their children's asthma. Hence, they take their chances to trial and error in managing their children's asthma.

Despite dietary alteration, 52 per cent (n = 623) of them believed that their child's diet was nutritionally well-balanced but 32 per cent (n = 387) were unsure of any nutritional deficiency.

Almost half (45 per cent, n = 925) of the parents surveyed did provide their asthmatic child with some vitamins or mineral supplements. This was intended to compensate for the dietary restrictions imposed on the child (23 per cent, n = 214), to remedy the child's "weakness" (23 per cent, n = 212) or for no particular reason (25 per cent, n = 230). The list of supplements include:

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  garlic pills;

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  evening primrose oil;

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  chicken essence;

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  royal jelly;

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  ginseng;

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  chlorella; and

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  barley.

Besides not having any proven value, some of these "supplements" may in fact cause adverse effects, such as royal jelly. Precipitation of asthma by royal jelly has been reported in many cases (e.g. Thien et’al., 1993). Furthermore, fibre and protein removed from the diet cannot be replaced by supplements.

Also, quality protein from milk/dairy products, eggs and fish, that are restricted or removed may not be sufficiently replaced by the supplements such as chicken essence. Certainly ginseng, chlorella, garlic pills and evening primrose oil do not have the necessary protein to replace them.

The source of information on food supplements was largely derived from friends and relatives (13 per cent), doctors (14 per cent), or their own initiative (19 per cent). The role of mass media in this area is much less with only 2 per cent, 3 per cent and 4 per cent reportedly derived from radio, television and newspapers, respectively. This observation may reflect a general lack of nutritional knowledge among Singaporen parents.

Furthermore, parents of asthmatic children are also of the opinion that some foods are important and should be consumed to avoid asthma symptoms. It was believed by 67 per cent (n = 1,222) of parents surveyed that the following have positive effects on their children's asthma:

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  wild meats (of crocodiles, bats, foxes, iguanas, turtles, pigeons, dogs, rabbits, frogs and camel's liver);

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  Chinese herbs (ginseng, cordycep, bird's nest, pearls);

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  durians;

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  ginger-water; and

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  almond soup.

This reflects a high prevalence of folklore therapy and beliefs amongst the Singaporean parents. There have been no vigorous scientific reports that these wild meats provide a higher biological valued-protein than the common and easily accessible chicken, fish, egg or milk.

If foods are restricted and the nutrients in those foods are not replaced from other sources, children may be at risk of nutritional deficiency which can affect their growth, as demonstrated in Labib et al.'s (1989) case study. In this study, a four year-old boy was investigated for short stature as he was being given a restricted diet with cow's milk, diary products, goat's milk, eggs, chocolate, sugar, food additives, fish, beef, lamb and pork withdrawn for purported food sensitivity. After eight weeks of normal diet, including reintroduced cow's milk, he gained 1.5 kg in weight and 2.0cm in height.

In this survey, it is noted that some of these Singaporean parents of asthmatic children administer other forms of therapy too. These include:

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  reflexology (5 per cent, n = 103);

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  aromatherapy (5 per cent, n = 97); and

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  acupuncture (2 per cent, n = 41).

Some studies reported that aromatherapy reduced anxiety and patients were more positive after the therapy (Dunn et’al., 1995). Milner (1993) reported that some herbal cures as such can be effective, but they act on the central nervous system rather than any local effects in the lungs. Many such homeopathy treatments have no control trials to verify, hence, the positive results could be due to "placebo" effect. Another study reported a 53-year-old diagnosed as having allergic airborne contact dermatitis due to a year-long exposure to lavender, jasmine and rosewood (Schaller and Korting, 1995). Although this study cited only one incident, there is a likelihood that we may not be aware of other similar cases that are diagnosed but not reported.

Discussion and recommendations

The information provided in this survey, depended on memory in some cases and on subjective interpretations of asthma and food "triggers" in others. Nevertheless, the results indicated a significant proportion of parents of asthmatic children, feel that food or drinks do affect their child's asthma. A great majority of them practise dietary restrictions or alterations, in managing their child's asthma, unwittingly not knowing what nutrients their children may be lacking. Perhaps one way to convince parents (without unpleasant confrontation), not to practise self-administered dietary restriction, is to conduct a food challenge, as did David (1987). David conducted a double blind challenge with tartrazine and benzoic acid on 24 children whose parents gave a definite history of a purely behavioural immediate adverse reaction to one of these additives. They were on a diet free of these items and no patient was observed with any change behaviour after the administration of placebo or active substances. Subsequently, 22 of them returned to normal diet without problems while the other two insisted on continuing the diet. Similarly, objective verification is therefore required in order to prevent unnecessary food restriction or avoidance in these asthmatic children.

A significant 88 per cent (n = 1,060) of those who practise dietary alteration, reported a noticeable improvement in their child's asthma. However, such observations may not be objective, as they are concluded without the health professionals' assistance. They may discover otherwise, as in the David et al. (1987) case, once a food challenge is conducted.

Parents of asthmatic children restrict their children's diet mainly on their own initiative. Many claimed to have been advised to do so by their doctors. In order to avoid unnecessary nutrient deficiency with such self-administered dietary restriction commonly adopted, an effective dietary education campaign is needed to reach both the parents and doctors. Many of the Singapore doctors are not trained nutritionists or dieticians. As primary health care professionals, they too should better acquaint themselves in nutrition before giving advice to their patients, or refer them to the relevant professionals.

Seminars and workshops can be conducted in schools, clinics, hospitals and community centers or clubs, to educate parents about the possible triggers of asthma, exercises to strengthen their children's immunity and lungs. It is important to stress the "barrel" effect of asthma attacks so as to avoid unnecessary restriction or avoidance of exercises and food. Good dietary practices using the food guide pyramid to help them plan their children's meals, will further equip them with confidence in coping with their asthmatic children.

Supportive groups and hotlines are also good alternatives to provide efficient support to such parents. These avenues can help to prevent undue anxieties and unnecessary food avoidance practices.

The Singapore Asthmatic Association (SAA) can play a helpful role in providing the psychological and emotional support too. SAA can organise nutrition workshops to help parents in better understanding their children's diet and subsequently planning their healthy diet. Self-help groups consisting of parents of asthmatic children can also be organised to provide morale encouragement and support. Exercise rehabilitation programmes that strengthen the lungs and chest muscle can also be introduced as another healthy management strategy. Hotlines provided by asthma clinics and hospitals can also be very helpful.

Schools can also consider incorporating exercise rehabilitation for asthmatic children in the form of extra curriculum activities, installing asthmatic first aid kits and having teachers trained about asthma management and to keep a look out for these children (American Academy of Pediatrics, 2001). It is noted that a large number of Olympic athletes and other top sportsmen and women are asthmatic. As long as their asthma is well controlled, there is no reason to stop an asthmatic child from helpful exercises (Morton, 1994). To reinforce the above, specific instrumental messages can be printed on pamphlets to be distributed at public venues.

Childhood asthma generally tends to improve with time. Those wheezing without obvious allergic triggers in the first few years of life, may well be asymptomatic by the age of six or seven years, and even those with obvious atopy are likely to improve by or during adolescence (Milner, 1993). There are now a number of epidemiological studies on the natural history of wheezing and coughing after bronchiolitis, indicating that 80 per cent will have symptoms in the two years after the acute attack (Webbs et’al., 1985), but of these less than half will still have symptoms by the time they reach the age of five years, and less than 20 per cent by the age of ten years (Pullan and Hey, 1982).

However, in the process of "growing out" of asthma, the extent of dietary restriction and the types of restriction may have a great effect on the children's growth. Asthma was found to have no direct influence on growth in height, but was associated with delay in the onset of puberty (Balfour-Lynn, 1986). But once puberty finally began, complete catch up growth resulted in the attainment of the predicted adult height. The pre-adolescent physiological deceleration of growth velocity that occurs in these children gives the impression of growth retardations. Hence, like the case in the Labib study, parents may be over-anxious about the child's below average stature of height and weight, even though his the rate of growth was normal. Furthermore, nobody would like to grow up from a childhood with severely restricted diet and games (some parents also restrict children from running too much), while seeing their peers enjoying themselves.

Besides drugs and dietary management, non-pharmocological means of preventing asthma could be simple and effective. Cessation of smoking in the home is one of the most important actions recommended (Price, 1990). There is a highly significant increase in wheezing, coughing and respiratory infections in children with smoking mothers. Core blood IgE levels are increased in babies whose mothers smoke during pregnancy. Other environmental agents such as chemical pollutants from industrial processes play a role in the development of asthma symptoms and should be avoided. Avoiding allergens at home, such as dust mites, pets etc., with constant hoovering under the beds and sofa. Other means of reducing the chances of asthma attacks, where some people found them to be effective, include those of adding a plastic sheet below the mattress or using ionizers.

Awareness of environmental conditions that hinder breathing in children with asthma is a key to effecting good control of the disease. One way to improve the health of young children is to reach out to day care centres. A great majority of Singapore mothers are working, and thus children typically spend 20 per cent to 30 per cent of their lives (and the majority of their waking time) at a day care facility. It is therefore important that care-takers pay attention in reducing potential allergens such as stuffed animals and have sound nutritional knowledge, so that undue dietary restrictive management is not practised.

With the increasing orientation towards "natural" modes of treatment, it is not surprising to find many of these parents adopted therapy such as reflexology, aromatherapy, herbal folklores or acupuncture. Such self-medication, without the purported supervision from the medical profession, presents a risk in their children's health or even their lives.

Conclusion

When asthma is not managed properly, children frequently miss school and are unable to participate in sports and other activities. Although medications can provide symptomatic relief and ease the inflammation of irritated airways, comprehensive asthma care includes more than drugs.

Although information given in the survey study depended on memory in some cases and retrospective interpretation of asthma/food allergy by the person who filled in the questionnaire, nevertheless, the results indicated that a great majority of parents were uncertain about their children's diet and pediatric asthma. It is recommended that an effective and aggressive dietary education campaign in coping with asthma be launched along the proposed content guidelines. A separate detail food challenge study can also be undertaken to confirm the parents' beliefs further and hopefully to change their unnecessary dietary avoidance practices.

Kai Ling Ang and Schubert FooNanyang Technological University, Singapore

Appendix