Epileptic people are a difficult group to study due to frequent mental, behavioral and social problems [17, 26]. The current studies on dietary behavior and lifestyle in this group of patients are limited [9, 12, 17, 27, 28] and need to be expanded. In this study, recruitment for the research took place in 2016–2019 through various information channels. In the end, 70 epilepsy patients were enrolled in the study, which was quite a good result considering the reluctance of epileptic patients to participate in scientific research [29]. Finally, 60 people were qualified for further research. Of them, 23.3% had mental illnesses or disorders and were therefore supported by caregivers. Compared to healthy people, in this study only 36.7% of epileptics had a permanent job compared to 82.9% of healthy controls, and as much as 36.7% compared to 2.9% in the control group received a pension/retirement. The control and study group did not differ in terms of gender, age, BMI and vitamin D supplementation.
Studies show that epileptic patients have a higher risk of comorbidities including dyslipidemia [10, 30], which is a risk factor of cardiovascular disease. One of the risk factors of dyslipidemia can be antiepileptic treatment, but it cannot be clearly determined which kind of medication (drugs and drug combinations) has the greatest impact [31]. In some studies, the monotherapy with old-generation drugs, such as carbamazepine, valproic acid, and phenytoin, was associated with an increase in cardiovascular risk [32]. In contrast, a study by Vicanco-Hidalgo et al. [33] concluded that, despite a higher percentage of dyslipidemia in epileptic patients, they do not have a greater cardiovascular risk. In the above study compared to healthy people, epileptic individuals had a lower rate of hypertension and diabetes [33], what indicates the need for a better assessment of epileptic patients prior to statin treatment. In our study, patients were treated with various antiepileptic drugs, both in mono- and polytherapy. Although we found elevated levels of LDL-cholesterol in the blood serum of epileptic patients compared to the controls, the results were not statistically significant. No significant differences were found between these groups with respect to other lipids. These and other findings suggest that the epilepsy treatment may not be the only factor behind dyslipidemia. Some other factors, such as dietary behavior and lifestyle, can contribute to disorders of lipid metabolism. Kim et al. [27] analyzed the effect of lifestyle modification and the use of statins on the reduction of vascular risk in patients with epilepsy. Pharmacotherapy was found to be more effective, but lifestyle changes also had positive effects.
There are very few studies in the literature on nutritional status and dietary habits in epilepsy. One of them, the California Health Interview Survey, concluded that the eating behavior and physical fitness in epilepsy are similar to these of healthy people [28]. In contrast, some evidence shows that epilepsy may increase overweight and obesity, as well as the risk of cardiovascular diseases [10]. The percentage of overweight and obesity measured in our study was 53.4% for epilepsy patients and 52.8% for healthy controls, which was similar to another study where this percentage was 55.2% [34]. In addition, we analyzed the body composition using electrical bioimpedance. A significantly higher percentage of body fat (PBF) was found among epileptic men compared to the healthy men, 27.65% and 22.2%, respectively. However, no significant differences were found among women. There is not much research on body composition in epilepsy. In another study, patients treated with antiepileptic drugs had a PBF similar to the controls [35]. According to the World Health Organization (WHO), abdominal obesity is a risk factor of metabolic diseases [36]. Overall, the average waist-to-hip ratio (WHR) in this study, for both women and men, regardless of the prevalence of epilepsy, was above the normal range. Due to these results and the associated risk of metabolic diseases, it is reasonable to pay attention to the dietary behavior of patients with epilepsy [37]. Some studies show high carbohydrate and protein intake in epilepsy as well as low fat intake, including polyunsaturated fatty acids [12]. In contrast to these results, our research shows a different tendency. While carbohydrate and protein intakes were at the recommended levels, more fat was consumed by the epilepsy patients compared to the controls. In turn, the intake of polyunsaturated fatty acids (PUFAs) was at a similar level in both groups of participants. Compared to another study [12], the average cholesterol intake in epilepsy patients was in the normal range, both in men and in women.
The frequency of food consumption was further analyzed. It was found that patients with epilepsy showed less favorable eating behavior compared to healthy people. They have consumed significantly less frequently vegetable products such as fruit, pulses, seeds, and nuts, which are sources of vitamins, minerals, and dietary fiber. These food products are recommended for the prevention of cardiovascular risk [38]. Compared to other studies [28], epilepsy patients in our study showed less frequent consumption of vegetables and fruits and sugar sweetened soda, while they consumed legumes more often. Some countries have formulated dietary guidelines for epilepsy patients. In the UK, the dietary recommendations emphasize a balanced diet providing all macronutrients, with particular emphasis on vegetables and fruits [39]. Attention is also drawn to foods that provide complex carbohydrates, which raise blood glucose levels more slowly and for longer, allowing a longer sense of satiety after a meal. Similarly, the dietary recommendations for the US patients are mainly based on the elimination of monosaccharides and food products with high glycemic indexes from the diet, while promoting a balanced, varied diet and an appropriate amount and quality of fluids [40]. In our study, epileptic participants consumed less dairy products, including cottage cheese, which is a source of easily absorbable calcium, important for bone health. In addition to this, fish and eggs, which are food sources of vitamin D, were consumed less frequently, but this difference was insignificant. It is worth noting that patients with epilepsy also showed a lower serum concentration of 25(OH)D3. In this study, epilepsy patients were more likely to consume sugar-sweetened soda, which, due to the content of sugar, preservatives, and dyes, are considered less beneficial to health [41].
The intake of stimulants such as coffee and alcohol was analyzed in this study. Patients with epilepsy consumed coffee less often than healthy individuals. There are many indications that regular coffee drinking may exacerbate seizures in some patients due to the effect on the central nervous system [42, 43]. So far, the role of caffeine in the control of epilepsy is unclear. Studies on animal models suggest that, depending on the dose and length of caffeine intake, it may have both positive and negative effects on seizure control [44, 45]. Moreover, caffeine may reduce the effectiveness of some anticonvulsant drugs, mainly topiramate [46]. Some studies indicate the need to reduce caffeinated beverages due to the possibility of increasing the frequency of epileptic seizures and reducing the effectiveness of anticonvulsant drugs. It should be noted that caffeine is not currently considered a seizure inducing factor [47].
Epileptic participants in this study consumed alcohol less frequently than the control group, and this finding is consistent with Elliot et al. [28]. A study by Hinnell et al. [48] found that patients with epilepsy consumed alcohol less frequently than the general population; however, one-fourth of them declared regular use of alcoholic beverages. In another study, patients with epilepsy declared addictive drinking less frequently than healthy people [49]. The influence of alcohol consumption on the occurrence of epileptic seizures is the subject of many studies. Some of them suggest that moderate alcohol consumption does not increase the frequency of seizures, while others show the possibility of intensifying epileptic seizures due to various mechanisms of action, e.g., effects on neurotransmission and metabolic changes [50]. Hamerle et al. [51] found a negative impact of significant amounts of alcohol in epileptic patients, but concluded that moderate consumption seems safe for most patients. Scientific research has been reflected in dietary recommendations for epileptic patients. The recommendations for patients in Australia point to the negative consequences of alcohol consumption, especially of larger quantities, and the need to consult a physician in relation to the type of drugs taken [52]. It is important that alcohol may interact with anticonvulsant drugs, reduce their effectiveness, intensify side effects, and increase the risk of seizures, caused by sleep disturbances and reduced sleep quality [53].
The analysis of vitamin and mineral intake showed that most (over 80%) of the deficient nutrients were folic acid, vitamin D, and calcium. This is particularly important due to the role of B vitamins, including folic acid and vitamin D, in proper development and functioning of the nervous system [54]. Moreover, vitamin D and calcium are responsible for bone and mental health, and patients treated with antiepileptic drugs are particularly vulnerable to osteoporosis and depression [55]. Other studies have shown low calcium intake by patients with epilepsy [56]. The study also showed significantly lower vitamin C and potassium and higher sodium intakes by epileptics. In contrast to supplementation studies, meta-analyses of prospective studies found that higher dietary intakes of vitamin C and potassium were associated with reduced risk of cardiovascular disease [57, 58]. On the contrary, increased sodium intake was associated with higher mortality due to CVD [59]. The intake of minerals and vitamins in epilepsy has been rarely studied. Therefore, there is a need for more research that would allow for a formulation of dietary recommendations for this group of patients, taking into account potential deficiencies in these nutrients.
The role of vitamin D in the etiology and course of epilepsy is still not clearly understood; however, in the 1990s, a higher birth rate of children with epilepsy was observed in the winter period [60]. It has also been noted that, in patients with epilepsy, both the severity of epileptic seizures, their frequency, and the number of sudden unexpected deaths occur during the winter period when insolation is limited [61]. In animal models, vitamin D may reduce the severity of chemically induced seizures and increase the anticonvulsant effect of some antiepileptic drugs [62, 63]. However, studies assessing serum concentrations of 25(OH)D3 in epileptic patients are still scarce. In a study conducted in India, lower average serum concentrations of vitamin D were observed compared to our results [64]. It should be noted that, although the territory of India is characterized by high sunshine, clothing covers most of the body, limiting skin synthesis of vitamin D. Cultural differences and skin pigmentation are also important. In the above study, no significant differences by gender or between the study and control groups were found. A recent literature review found that the vitamin D deficiency affects the entire European population [65]. Other European studies showed significantly lower serum concentrations of vitamin D in epilepsy patients, but also lower seizure rates after vitamin D supplementation [66]. However, it should be noted that this study was conducted on a small group of 13 patients with epilepsy. A larger US study found a frequent vitamin D deficiency in patients with epilepsy [67]. The average serum concentration of 25-hydroxyvitamin D was lower than in the general population.
A significant part of research on epilepsy concerns the influence of antiepileptic drugs, which cause a decrease in blood vitamin D concentration, which in turn negatively affects the skeletal system [68]. When considering the possible influence of drugs on vitamin D, one should mention the frequent co-occurrence with epilepsy of other disorders, including mental disorders. Mental disorders occurring during the interictal period are the most common problem in epilepsy patients. Dementia syndrome, interictal psychosis, and affective disorders such as mania or depression among the interictal psychiatric disorders can be distinguished. Patients with mental disorders are particularly at risk of vitamin D deficiency, especially those treated with clozapine, as well as people with low physical activity and poor eating habits [69].
Physical activity is an element of lifestyle, which is important for maintaining health. Although participants with epilepsy as well as healthy participants in the study were moderately active, patients with epilepsy spent more time during the day sitting and less often performed intensive and moderate physical activity during the week, what is consistent with other findings [70]. Lower physical activity may be affected by low occupational activity of epileptics compared to healthy people, 36.7% compared to 82.9%, respectively. The latest meta-analysis of population studies shows that further research is needed before specific recommendations on physical activity in people with epilepsy are formulated [70]. Among patients with epilepsy, but not in the control group, a positive relationship was found between the level of physical activity and serum concentration of vitamin D3. Vitamin D is mainly synthesized by sunlight, so outdoor physical activity can increase the concentration of this vitamin in the blood serum. Some studies, however, show that any type of physical activity, including indoor activity, may increase the synthesis of vitamin D [71], which was also found in our study. Although there were no significant differences in the level of physical activity between the study group, in which the serum vitamin D concentration was significantly lower, and healthy controls, the level of physical activity in both groups was estimated to be moderate. However, participants with epilepsy spent much less time walking and more time sitting. Moreover, in epileptics, a weak positive correlation was observed between vitamin D concentration in blood and time spent walking and between vitamin D and overall physical activity. There was also a weak negative correlation between vitamin D concentration and the time spent sitting. Unfortunately, numerous studies indicate that people with epilepsy are less physically active and less willing to participate in sports activities [72]. In general, fewer people with epilepsy show physical activity at the recommended level [44]. Importantly, other studies address the potentially beneficial role of physical activity in improving the cognitive function of patients with epilepsy [73] and quality of life [74]. Scientific evidence indicates that it is reasonable to educate patients with epilepsy about their lifestyle. Despite the proven role of physical activity in epilepsy, as shown by research results, recommendations for physical activity are not uniform. In some countries, epilepsy patient associations promote recommendations for physical activity [75]; however, there are no general guidelines. When making such recommendations, factors such as the type of epilepsy, seizure control, type of treatment, and safety of various forms of physical activity should be taken into account [76].
This study has several limitations. It assessed various aspects of nutritional behavior and lifestyle, as well as biochemical and anthropometric parameters, which is a strength of this study, but can also be a burden on participants. Therefore, a smaller number of respondents volunteered to take part in the survey than initially assumed. On the other hand, the data obtained during the research was complete for each participant. Another limitation is related to data on dietary behavior and physical activity that have been self-reported and may therefore be biased.