Ulcerative colitis (UC) is an inflammatory bowel disease with an incidence rate of 10/100 000 people within the UK and a point prevalence of 200/100 000( Reference Ho, Lees and Satsangi 1 ). It is a chronic disease and is usually diagnosed between late adolescence and early adulthood and affects both sexes equally( Reference Ho, Lees and Satsangi 1 , Reference Loftus 2 ). UC has a direct effect on patients’ quality of life and is associated with numerous health complications such as toxic megacolon, strictures and colorectal cancer( Reference Hart, Luben and Olsen 3 , Reference Danese and Fiocchi 4 ). UC involves inflammation and development of ulceration on the lining the colon and rectum, collectively known as the large bowel( Reference Ho, Lees and Satsangi 1 ). Symptoms include ulcers and open wounds on the surface of the lining, possibly causing gastrointestinal bleeding, weight loss and diarrhoea( Reference Ho, Lees and Satsangi 1 ). UC patients will frequently report urgency for the toilet with more than five bowel movements per d( Reference Nikolaus and Schreiber 5 ). Some may experience further problems outside the bowel including skin problems, ocular conditions, and musculoskeletal system, haematopoietic and coagulation system complications( Reference Danese and Fiocchi 4 ). The cause of UC is unclear, but research indicates a multitude of factors interacting together including genetics, immune responses and infective mechanisms( Reference Lomer 6 ). In addition, ethnicity, age and geographical locality can have an impact on those affected by UC( Reference Lomer 6 ). Western lifestyles, smoking, dietary habits and infections during childhood play a significant role, compounding the incidence rates of UC.
Due to bowel inflammation during heightened disease activity, nutritional requirements and habits may need to be changed to assist recovery and prevent aggravation of the bowel( Reference Neuman and Nanau 7 ). The consumption of smaller portions and reduced amounts of fibre and fatty foods is recommended as they exacerbate symptoms during disease flare-ups( Reference Lomer 6 ). Avoidance of insoluble fibre is recommended while patients are in treatment, due to it being indigestible and attaching itself to the wall of the colon while inflamed( Reference Colitis 8 ). This action aggravates the colon and can worsen symptoms. Soluble fibre is alternatively recommended, with easier digestion, thereby not aggravating the inflamed bowel( Reference Colitis 8 ).
Despite conflicting evidence that diet is related to disease activity, patients are assured that diet is not the primary cause of UC( Reference Magee, Edmond and Tasker 9 ). Many patients associate symptoms with eating particular foods, frequently leading to avoidance of particular food groups, such as dairy products( Reference Lomer 6 ). Perhaps due to misinterpretation of UC diet guidance or self-seeking information, some patients may experiment with elimination diets and cut out important food groups( Reference Lomer 6 ). Some may be exposed to inaccurate information regarding UC diets and confuse symptoms with food allergies( Reference Moneret Vautrin, Sainte-Laudy and Kanny 10 ). Consequently, patients might exclude foods that are required to adhere to healthy eating guidelines in efforts to alleviate UC symptoms( 11 ). Eating a variety of foods is essential for patients both in remission and in flare-ups to prevent possible nutrient deficiencies. Nutrient deficiencies may occur due to malabsorption from severe disease, loss of appetite, food avoidance and medication side effects, including lowered bone mineral density and vitamin D deficiency from steroid use and nutrient malabsorption( 12 – Reference Lucendo and Rezende 15 ).
Limited dietary guidance is provided to UC patients( Reference Lucendo and Rezende 15 ). Some have learnt that excluding certain foods can prevent flare-ups or help when in treatment( Reference Lomer 6 , Reference Magee, Edmond and Tasker 9 ). Little is known about patients’ food choice and its effect on dietary requirements( Reference Hartman, Eliakim and Shamir 16 ). Currently, aside from complete enteral nutrition, there are no clinical diets that have been proven to reduce disease activity or symptoms. Yet, patients continue to eliminate certain foods to alleviate symptoms( Reference Yamamoto, Nakahigashi and Saniabadi 17 ). Research is needed to assess what foods patients are eliminating, whether any alternative replacements are being made, and what the resulting effects on dietary intake and health are. The aims of the present study were to compare the dietary intakes of UC patients in the UK with the national recommended dietary intake values and to determine whether food avoidance contributes to not achieving these recommended intake values.
Methods
Study design and participants
In the present cross-sectional study, the diet adequacy and food avoidance habits of UC patients in the UK were investigated. The study was conducted according to the guidelines laid down in the Declaration of Helsinki, and all procedures involving human subjects were approved by the ethics committee of a UK Higher Education Institution. Written informed consent was obtained from all participants.
A total of ninety-seven UC patients were recruited across the UK from the National Association for Colitis and Crohn's Disease registers by e-mail, posts in UC forums and social media sites. The inclusion criteria were as follows: aged 18–65 years and no history of UC-related surgery.
A nineteen-question health questionnaire was used to assess UC patients’ health-related conditions, current nutritional knowledge, professional dietary guidance and food avoidance. The participants were asked which foods they avoided (by a choice) and which foods they have excluded from their diet (complete elimination from the diet). Some other questions included ‘Do you have any of the following as a result from ulcerative colitis? Osteopenia, Osteoporosis, Anaemia or Other?’, ‘What would you consider your nutritional knowledge to be? Basic, Intermediate or expert?’, ‘Have you received any nutritional guidance concerning ulcerative colitis? Nothing, a little, quite a lot, a lot?’, and ‘Have you received any nutritional guidance from the following: Dietician, Nutritionist, Government sources, websites, books or other sources?’. The questionnaire was written, designed and accessed through the online database Survey Monkey. Dietary under-reporting was assessed by Goldberg cut-off limits( Reference Goldberg, Black and Jebb 18 ).
Dietary intake data were collected using a 24 h dietary recall. Total energy intake (kJ/d), macronutrient intake (percentage of energy), fibre intake (g/d) and the intake of selected micronutrients were compared with the current national dietary intake values set by the Department of Health( 11 ). The percentage of energy derived from each macronutrient (carbohydrates, non-milk extrinsic sugars, protein, fat and SFA) was calculated by multiplying the weight of each nutrient in grams by the appropriate energy density and then by dividing the total energy intake. Fe, Ca, vitamin B12 and vitamin C intakes were compared with reference nutrient intake (RNI) values, and these are further discussed herein for the following reasons. Fe and Ca were chosen, as deficiency of these minerals poses higher risks of anaemia, osteopaenia and osteoporosis in UC patients( Reference Lomer 6 ). Vitamin B12 was chosen due to its dietary sources being those that are frequently avoided by UC patients( Reference Lomer 6 , Reference Lucendo and Rezende 15 ). Vitamin C, most commonly found in fruit and vegetables, was additionally chosen to investigate as UC patients frequently report the foods containing vitamin C as a trigger for a relapse in their condition( Reference Jowett, Seal and Phillips 19 )
Initially, four participants participated in a pilot study to ensure that the questionnaire and 24 h dietary recalls were readable and not distressing.
Data analysis
Statistical tests were carried out using SPSS version 20.0 (SPSS Inc.). In the preliminary analysis, the data were screened for missing values, outliers and univariate normality.
Dietary intake records were analysed using WISP version 3.0 (Tinuviel Software) nutritional analysis software. Missing food items’ nutritional data were manually entered into the software by either locating food composition from product manufacturers’ websites or McCance and Widdowson's Composition of Foods integrated dataset (6th Summary, UK Nutrient Databank, 2002, UK). The dietary intakes of macronutrients and micronutrients were compared with the current national dietary values using one-sample t test. Descriptive statistics (frequencies and mean values) were applied for questionnaire data, including nutritional supplements used, food avoidance, nutritional knowledge and patterns of dietary elimination.
Results
Participant characteristics
Participant characteristics and frequency data are given in Table 1. The majority of the participants were aged between 31 and 50 years (n 50). Females accounted for the majority of participation in the study (n 71, 73 %). Male participation was notably lower (n 22, 23 %). A large proportion (n 70, 72 %) of the participants had been diagnosed with UC within the past 10 years. Nearly a third of the participants (n 25, 26 %) were experiencing a flare-up of assorted severity, with a small number (n 2, 2 %) being in remission. Professional dietary support proved to be limited with the majority of the patients (n 71, 73 %) not being referred to a dietitian or nutritionist. Many received little or no dietary guidance, with only two participants (2 %) reporting that they were given a lot of dietary help. Over half of the participants (n 54, 56 %) reported to have basic nutritional knowledge, with various nutritional sources of information being used, including dieticians, official websites and books. Most did not experiment with media diets related to UC (n 67, 69 %). Anaemia (n 30, 31 %), osteopaenia (n 12, 12 %), osteoporosis (n 6, 6 %) and other nutrient deficiencies (n 9, 9 %) were reported.
Table 1 Participant characteristics and frequency data from the questionnaire (n 93)
UC, ulcerative colitis.
Dietary patterns
Dietary habits and preferences are shown in Figs. 1–3. Particular foods were continuously excluded by nearly half of the participants (n 47, 49 %), with less than a third (n 27, 28 %) occasionally excluding foods from their diets. Food avoidance was more predominant than food exclusion with fibre and fruit and vegetables being the most frequent food groups avoided. Other common food groups reported to be often avoided or excluded were milk and dairy products. The participants reported that their symptoms were alleviated a lot (n 24, 25 %), a little (n 54, 56 %) or not at all (n 11, 11 %) by avoiding such foods. The participants described a mixture of feelings towards food avoidance and how they felt it affected their symptoms (Table 2). Most of the participants avoided these foods during both flare-ups and remission (n 55, 57 %), whereas only few (n 25, 26 %) avoided them during flare-ups. The most used dietary supplements (Fig. 3) were Ca (n 31, 32 %), Fe (n 15, 16 %), multivitamins (n 15, 16 %), vitamin B12 (n 5, 5 %), n-3 fatty acids (n 7, 8 %), prebiotics and probiotics (n 6, 7 %), fish oils (n 4, 4 %), folic acid (n 3, 3 %), Zn (n 3, 3 %), vitamin C (n 2, 2 %), vitamin D (n 2, 2 %), herbal supplements (n 7, 8 %) and other (n 7, 8 %).
Fig. 1 Food exclusion patterns (expressed as percentage) of ulcerative colitis patients (n 93). (a) Food exclusion: 
, yes; 
, no; 
, sometimes; 
, not reported. (b) Foods excluded: 
, starchy foods – bread, pasta, and potatoes; 
, fruit and vegetables; 
, high-fibre foods; 
, milk and dairy products; 
, high-fat and sugary foods; 
, wheat and gluten; 
, red meat; 
, fizzy drinks and caffeine; 
, vegetable protein; 
, spicy foods; 
, alcohol.
Fig. 2 Food avoidance patterns (expressed as percentage) of ulcerative colitis patients (n 93). (a) 
, Starchy foods: bread, pasta, and potatoes; 
, fruit and vegetables; 
, high-fibre foods; 
, milk and dairy products; 
, high-fat and sugary foods; 
, wheat and gluten; 
, red meat; 
, poultry and fish; 
, fizzy drinks and caffeine; 
, vegetable protein; 
, spicy foods; 
, alcohol. (b) Time of avoidance: 
, remission; 
, flare-up; 
, both; 
, not reported. (c) Alleviation of symptoms: 
, not at all; 
, a little; 
, a lot; 
, not reported.
Fig. 3 Nutritional supplements used (expressed as percentage) by ulcerative colitis patients (n 93). 
, Calcium; 
, iron; 
, multivitamins; 
, folic acid; 
, zinc; 
, vitamin B12; 
, vitamin C; 
, vitamin D; 
, vitamin E; 
, n-3; 
, fish oils; 
, prebiotics and probiotics; 
, herbal supplements: Echinacea, aloe vera, starflower, and primrose; 
, other: glutamine, co-enzyme Q10, and turmeric.
Table 2 Thoughts of participants on food intakes
SCD, specific carbohydrate diet.
Food intakes
The food intakes of participants were compared with the national recommended intake values to assess whether they were adhering to dietary guidelines as shown in Figs. 4–6. The mean energy intake of all participants was 6364 kJ (1521 kcal) compared with the mean intake of 8025 kJ (1918 kcal) in males and females aged 19–64 years in the general population, emphasising reduced food consumption among these UC patients (Fig. 1). Energy intake was significantly low among the participants (P< 0·05), with only males (n 3, 33 %) aged 61–65 years achieving the recommended energy levels. Carbohydrate (44 % daily energy) and fibre (11 g/d) intakes, in particular, proved to be significantly low (P< 0·001) in this population. However, protein, total fat and saturated fat were consumed in excess (P< 0·001).
Fig. 4 Comparison of the mean daily macronutrient intake values of ulcerative colitis patients (n 81) and dietary reference values (DRV). 
represents cut-off point for the estimated average requirements for energy DRV for macronutrients set by the Department of Health(
11
). The following reference values were used: energy – 8117 kJ/d (1940 kcal/d) for females (
) aged 18–50 years; 7950 kJ/d (1900 kcal/d) for females aged 51–65 years; 10 669 kJ/d (2550 kcal/d) for males (
) aged 19–59 years; 9958 kJ/d (2380 kcal/d) for males aged 60–64 years; protein – 15 % of total daily energy intake; carbohydrates (CHO) – 47 % of total daily energy intake; non-milk extrinsic sugars (NMES) – 10 % of total daily energy intake; fat – 33 % of total daily energy intake; saturates – 10 % of total daily energy intake; fibre – 18 g/d. Values are means, with standard errors represented by vertical bars. Mean value was significantly different from the national recommended intake value set by the Department of Health(
11
): * P< 0·05; *** P< 0·001. E%, percentage of energy.
Fig. 5 Comparison of the mean daily micronutrient intake values of female ulcerative colitis patients (n 62) and reference nutrient intake (RNI) values. 
represents cut-off point for the RNI set by the Department of Health(
11
). The following reference values were used: iron – 14·8 mg/d for 19–50-year-old females (
) and 8·7 mg/d for 51–65-year-old females (
); calcium – 700 mg/d for all female participants; vitamin C – 40 mg/d for all female participants; vitamin B12 – 1·5 mg/d for all female participants. Values are means, with standard errors represented by vertical bars. Mean value was significantly different from the national recommended intake value set by the Department of Health(
11
): * P< 0·05; *** P< 0·001.
Fig. 6 Comparison of the mean daily micronutrient intake values of male ulcerative colitis patients (n 18) and reference nutrient intake (RNI) values. 
represents cut-off point for the RNI set by the Department of Health(
11
). The following reference values were used: iron – 8·7 mg/d; calcium – 700 mg/d; vitamin C – 40 mg/d; vitamin B12 – 1·5 mg/d for all male participants. Values are means, with standard errors represented by vertical bars. Mean value was significantly different from the national recommended intake value set by the Department of Health(
11
): 
, 19–50-year-old males; 
, 51–65-year-old males.
Fe (8·8 mg/d v. RNI 14·8 mg/d; P< 0·001) and Ca (573 mg/d v. RNI 700 mg/d; P< 0·05) intakes were significantly lower than the national recommended values in females aged 18–50 years, but proved adequate in other age and sex groups of UC patients. Vitamin C was excessively (92 mg/d; P< 0·001) consumed by females aged 18–50 years, while this trend was not observed in other UC patient groups. Vitamin B12 intake was adequate among all groups, with females aged 19–50 years achieving more than the required intake levels (2·26 mg/d; P< 0·05).
Discussion
UC affects both sexes equally and occurs in roughly one in five people in the UK( Reference Ho, Lees and Satsangi 1 ). Despite this, in the present study, females accounted for the majority of participation. Similar findings were reported by other researchers. A study investigating how young adults cope with inflammatory bowel disease concerns found that 80 % of the participants were women( Reference Gray and Clarke 20 ). No current evidence suggests that males find it harder to cope with UC; however, research shows that males are less likely to seek medical help and are less proactive about their state of health( Reference Gray and Clarke 20 , Reference O'Brien, Hunt and Hart 21 ), possibly explaining poorer male participation in the present study.
The energy intake of UC patients (Fig. 4) who participated in the present study was significantly lower than the estimated average requirements( 11 ). This is in accordance with studies showing malnutrition among UC patients( Reference Lomer 6 , Reference Lucendo and Rezende 15 , Reference Geering, Badart-Smook and Stockbrugger 22 ). Poor appetite, weight loss and low food consumption have been suggested to contribute to compromised energy intakes( Reference Lucendo and Rezende 15 , Reference Geering, Badart-Smook and Stockbrugger 22 ). In the present study, 26 % of the participants avoided foods during flare-ups to alleviate symptoms (Fig. 2), and 44 % of the participants were flaring, possibly influencing the majority of participants not achieving adequate energy intake levels. However, 57 % of the participants avoided foods both during remission and flare-ups, increasing the likeliness of deficiencies when food intakes should be adequate. Furthermore, only 2 % of the participants avoided foods during remission alone.
Although food avoidance was prevalent in 57 % of the participants, only 49 % reported that eliminating certain foods helped alleviate symptoms, indicating more people avoid foods than required. The thoughts of participants varied on how food affected their UC and alleviated symptoms (Table 2), despite the reassurance given to patients by health professionals that food does not affect disease activity( Reference Magee, Edmond and Tasker 9 ). Foods high in fibre were avoided by the most of the participants, followed by alcohol and fruit and vegetables (Fig. 2). Fibre intake was significantly low (P< 0·001), with only 6 % achieving the recommended intake level of 18 g/d( 11 ). Fibre intake in the general population is also low, currently reported to be 13·8 g/d( 23 ). Nevertheless, lower consumption of fibre was anticipated in the participants as insoluble fibre and low-fibre foods are often recommended to prevent aggravation to the inflamed bowel( Reference Colitis 8 ). Observation from the literature shows that there is conflicting advice provided to inflammatory bowel disease patients with regard to fibre intake( Reference Colitis 8 , 24 ). Some sources recommend the consumption of low-fibre residue foods only during flare-ups, while others distinguish between soluble and insoluble fibre foods and recommend avoiding only insoluble fibre foods. This highlights the importance of consistency in national recommendations of dietary fibre intake for UC patients, including detailed differences in the types of fibrous foods, such as insoluble fibre foods, that should be avoided during relapse. Consistent advice and recommendations regarding the appropriate times to exclude fibre foods and to reintroduce them should be provided to UC patients. This would enable patients to make more informed choices, even when individual differences may need to be taken into account. Consequently, patients may be excluding both insoluble and soluble fibre foods due to misunderstanding their difference from conflicting advice, highlighting the importance of adequate and consistent professional dietary advice and guidance. The consumption of fruit and vegetables is currently recommended depending on the cooked state and fibre content( Reference Colitis 8 ). For example, low consumption of fibre cooked fruit and vegetables, without skins, rather than that of raw and uncooked high-fibre fruit and vegetables is recommended. Yet, avoidance of fruit and vegetables was reported by 36 % of the participants. This is comparable to that of the general population, as fruit and vegetable intake is below the recommended levels, with adults aged 19–64 years consuming 4·2 portions/d( 23 ). High fibre content may have encouraged further avoidance of fruit and vegetables by the participants, preventing them from eating an essential food group regardless of dietary advice (Table 2). Wheat and gluten-containing products were avoided by 13 % of the participants and excluded by 9 %, highlighting a difference between food avoidance and food exclusion. Limiting the consumption of these foods is not commonly advised; therefore, the participants may be practising unnecessary exclusion and perhaps confusing symptoms with food allergies( Reference Moneret Vautrin, Sainte-Laudy and Kanny 10 ). This can also be applied to avoidance of dairy products, which featured among 25 % of the UC patients and excluded by 13 %. This correlates with the results of studies highlighting avoidance of dairy products to alleviate symptoms( Reference Lomer 6 , Reference Magee, Edmond and Tasker 9 , Reference Prescha, Pieczynska and Biernat 25 ). The percentage of participants who avoided dairy products was higher than the proposed 10–20 % who suffer from dairy intolerance( Reference Mishkin 26 ). This suggests that UC patients who are not dairy intolerant may avoid dairy products needlessly, as suggested by Mishkin( Reference Mishkin 26 ). Yet, some argue that avoidance of dairy products is more common in inflammatory bowel disease patients than in the general population, possibly explaining greater avoidance( Reference Prescha, Pieczynska and Biernat 25 ). This may affect those with osteopaenia and osteoporosis, a possible risk factor for patients( Reference Magee, Edmond and Tasker 9 , Reference Prescha, Pieczynska and Biernat 25 ). Despite research emphasising protein derived from meat, particularly red meat, as a trigger for worsening UC activity( Reference Tilg and Kaser 27 – Reference Ripoli, Miszputen and Ambrogini 29 ), very few participants avoided red meat, with only one participant avoiding poultry and fish (Fig. 2).
Limited nutritional guidance can result in food avoidance( Reference Lomer 6 ). Some argue that dietary advice is essential straight after diagnosis to ensure suitable intakes of the appropriate foods to prevent malnutrition( Reference Lomer 6 ). In the present study, 37 % of the participants received no dietary guidance and only 24 % were referred to a dietitian or nutritionist after diagnosis, coinciding with findings of restricted access to dietary services( Reference Lomer 6 ). Subsequently, research suggests that UC patients may seek information from unreliable sources and experiment with food avoidance and exclusion to alleviate symptoms( Reference Lomer 6 , Reference Magee, Edmond and Tasker 9 ). In the present study, many participants acquired information through unofficial sources including websites and books. The amount of reliable information found outside professional guidance is unclear, possibly causing exclusion of wrong foods( Reference Lomer 6 ). In addition to this, inadequate nutritional knowledge may affect the patients’ decision to eliminate and experiment with the guidance provided. In the present study, 56 % of the participants reported that they considered themselves to have basic nutritional knowledge, potentially making them vulnerable to misinterpretation of evidence. Furthermore, 69 % of the participants did not follow media-related diets to alleviate their UC, but the remaining participants had followed various unknown and unofficial UC diets.
In terms of macronutrient intake, the diets of UC patients who participated in the present study were lacking carbohydrates and fibre, while they were abundant in protein and fat. Carbohydrate intake was low with only 34 % achieving the national recommended levels (Fig. 4). This value is somewhat lower than that found in the study of Prescha et al. ( Reference Prescha, Pieczynska and Biernat 25 ), in which the mean daily intake percentage for females was 51 % and that for males was 48 % compared with 44 % in all participants of the present study. Only three participants excluded complex carbohydrates to alleviate symptoms, indicating that low intakes may be influenced by disease activity and reduced appetite( Reference Lucendo and Rezende 15 , Reference Prescha, Pieczynska and Biernat 25 ). Additionally, the participants did not overconsume non-milk extrinsic sugars( 11 ) (Fig. 4). This may contribute to low carbohydrate intakes due to 13 % reporting that avoidance of sugary foods helped alleviate symptoms. However, low exclusion of complex carbohydrates suggests that less people experience symptoms associated with this food group, giving less reason for elimination diets( Reference Nikolaus and Schreiber 5 , Reference Yamamoto, Nakahigashi and Saniabadi 17 ). Fat intake percentages were significantly higher (P< 0·001) than the dietary reference values with a mean intake of 37 %. The results are similar to findings from the study of Prescha et al. ( Reference Prescha, Pieczynska and Biernat 25 ), in which the fat intake percentages of participants, notably males, were higher at 38 %, while their carbohydrate intake percentages were below the recommended levels at 48–51 %. The participants of the present study reported consuming butter and confectionery, despite advice to reduce the consumption of fat-rich foods. High intakes of fat, specifically linoleic acid, are associated with increased incidence rates of UC( Reference Tjonneland, Overvad and Bergmann 30 ). Excessive fat intake indicates poor patient compliance to professional dietary advice, particularly as surplus dietary fat has been shown to worsen the symptoms( Reference Tjonneland, Overvad and Bergmann 30 ).
A significant proportion of the participants (P< 0·001) were achieving vitamin B12 intake above and beyond the recommended levels. The main dietary sources of vitamin B12 are milk and meat sources; the participants are likely to derive vitamin B12 from meat, fish and alternative sources due to reduced intakes of dairy products. Although previous studies have linked protein foods with increased relapse( Reference Jowett, Seal and Pearce 28 , Reference Ripoli, Miszputen and Ambrogini 29 ), all participants of the present study achieved RNI levels for protein, indicating that vitamin B12 was obtained from meat and poultry sources with some age groups consuming excessive protein. High consumption of protein is sometimes advised due to the loss of protein in the large bowel from inflammation, immune responses, tissue repair and increased metabolic requirements( Reference Prescha, Pieczynska and Biernat 25 , Reference Gerasimidis, McGrogan and Edwards 31 ). Prescha et al. ( Reference Prescha, Pieczynska and Biernat 25 ) argue that 17 % additional energy should be consumed via protein, ideally poultry, fish and well-tolerated dairy products, during early remission because of its crucial role in the treatment of the disease, allowing the patients to recover more successfully. Exclusion of dairy products by the participants appears to have little impact on overall protein intake, as other sources were not excessively avoided (Figs. 2 and 4). Vitamin C was another vitamin that the participants, excluding females aged 51–65 years, consumed excessively (P< 0·001) compared with RNI levels; therefore, vitamin C food sources are less likely to be excluded and this vitamin is likely to be gained from sources other than fruit and vegetables.
Ca intake was significantly low (P< 0·009) in females aged 19–50 years, with 31 % overall achieving RNI levels with a mean intake of 602·37 mg/d, which is 41 mg lower than that of the participants of the study carried out by Prescha et al. ( Reference Prescha, Pieczynska and Biernat 25 ) (Figs. 2 and 3). UC patients are particularly vulnerable to developing low bone mineral density, osteopaenia and osteoporosis from steroid use, malabsorption and dairy product avoidance( Reference Lomer 6 , Reference Magee, Edmond and Tasker 9 , Reference Prescha, Pieczynska and Biernat 25 ). Associated health conditions were prevalent among 12 % of the participants with osteopaenia and 6 % with osteoporosis in the present study. Half of the participants had only been diagnosed with UC within the past 5 years; therefore, deficiency risks may be even higher among those who have been diagnosed for a longer period (Table 1). Some argue that patients require daily Ca supplements at 1000 mg to account for dairy product avoidance( Reference Lomer 6 ). Nevertheless, only 32 % of the participants took Ca supplements. Dietary intake analysis does not factor in nutritional supplements due to dosages and amounts not being provided by the participants.
Fe stores are frequently low due to intolerance and elimination of Fe-rich foods, blood loss and gastrointestinal sores( Reference Lomer 6 , Reference Yamamoto, Nakahigashi and Saniabadi 17 ). Anaemia can occur in up to 80 % of patients, highlighting the need for prevention( Reference Lomer 6 ). Asakura et al. ( Reference Asakura, Suzuki and Kitahora 32 ) found that animal produce increased relapse in patients, potentially leading to meat exclusion. However, in the present study, the poultry intake of participants was adequate and red meat was eliminated by only 7 % of the participants (Fig. 1). Low Fe intake may be explained by the lower consumption of vegetables due to high avoidance. However, bioavailability is greater from meat sources, suggesting that reduced energy intake greatly affects Fe intake. Anaemia was present among 31 % of the participants and yet only 16 % took supplements, suggesting that the affected patients may endure the deficiency to avoid taking supplements, fearing side effects and unmanageability as previously found in up to 21 % of UC patients( Reference Yamamoto, Nakahigashi and Saniabadi 17 , Reference Tilg and Kaser 27 , Reference James, Irving and Gearry 33 , Reference Gasche, Lomer and Cavill 34 ). Fe intake was significantly low in females aged 18–50 years (P< 0·001) with only 15 % achieving RNI levels. Females aged 51–65 years consumed less than the recommended levels, but showed no significant difference when compared with the recommended levels. Fe intake among males was adequate, implying significant blood loss rather than low Fe intake to be the primary problem in female patients( 11 ). The difference among the participants is probably due to females aged between 18 and 50 years requiring higher RNI levels to account for greater blood loss during menstruation( 11 ). If food intakes are generally low, achieving RNI levels will be difficult, specifically within this group. Healthy females sometimes require additional intakes or supplements for excessive blood loss through menstruation. This highlights the additional risk of Fe deficiency in young female patients.
Conclusion
The present results highlight obvious avoidance of food groups, in particular, fibre, alcohol, and fruit and vegetables. Foods recommended by health professionals to be excluded during treatment and flare-ups were generally avoided, but the participants displayed poor compliance elsewhere such as excessive fat intake. The participants were not achieving appropriate energy intake levels, resulting in low carbohydrate, Ca and Fe intakes among younger females, emphasising poor adherence to healthy eating guidelines. However, it is important to consider that intakes will vary when in remission or flare-ups as symptoms often discourage many from eating. Food intakes could have improved had professional dietary guidance been consistently provided. Health services disappoint participants in dietary guidance despite being a crucial knowledge source, leading many to eliminate foods and research elsewhere to alleviate symptoms, regardless of its accuracy. Perhaps with immediate interventions, deficiencies may decrease where non-essential food avoidance exists, particularly during remission. Still, this may be difficult to achieve as patients react differently to certain foods, leaving them to develop their own dietary habits that may not adhere to recommendations.
Limitations
It would have been advantageous to increase male participation to further address sex differences in food intakes. A more evenly distributed age range would have been valuable to assess factors such as osteoporosis risk among older participants. Additionally, the accuracy of 24 h dietary recall could be questioned, as it may not have provided the true reflection of habitual intake of the participants. For more accurate dietary intake analysis, it would have been highly valuable to gain information on participants’ supplement dosages to establish their contribution to nutrient intakes.
Acknowledgements
The authors thank the National Association for Crohns and Colitis for assistance in the research study and also the participants for enabling the study to take place.
The authors’ contributions are as follows: M. W. designed and produced the research questions and study, recruited participants through various sources and additionally conducted the research, examined the data with I. A. and carried out the appropriate statistical analysis and wrote the article, taking full responsibility for the finished work; I. A. edited the manuscript and was responsible for the final draft.
The authors declare no conflicts of interest.
