Dietary treatments that affect brain neurotransmitters. Effects on calorie and nutrient intake

Lifestyle - A Common Denominator for the Onset and Management of Migraine Headache: Complementing Traditional Approaches with Scientific Evidence

Background:

Ayurveda and Yoga have gained popularity in the management of various chronic health problems associated with pain including migraine headache. It is evident from both scientific as well as traditional literature that stress, diet, sleep, and exposure to extreme climatic conditions act as triggering factors for the onset of migraine. Hence, it is essential to focus on lifestyle including diet as important factors for prevention and as adjuvant factors in the management of migraine headache.

Aim:

The aim was to propose a new perspective to the understanding of migraine headache keeping in view the role of lifestyle including diet.

Methods:

Classical Ayurveda texts and traditional Yoga scriptures were used to compile information on the role of lifestyle including diet in the onset and management of migraine headache. This was complemented by PubMed-based review of scientific literature.

Outcome:

Ayurveda texts provide an extensive information about the basic understanding, causes, precipitating factors, and management of migraine headache, while Yoga texts refer to the concept of mental stress (adhi) leading to physical health problems (vyadhi). It is evident from the literature that diet, sleep, exposure to extreme climatic conditions, and mental stress play an important role in the onset and management of migraine headache.

Conclusion:

Lifestyle appears to be the common factor for both onset and management of migraine headache.

Genetic and biochemical changes of the serotonergic system in migraine pathobiology

Migraine is a brain disorder characterized by a piercing headache which affects one side of the head, located mainly at the temples and in the area around the eye. Migraine imparts substantial suffering to the family in addition to the sufferer, particularly as it affects three times more women than men and is most prevalent between the ages of 25 and 45, the years of child rearing. Migraine typically occurs in individuals with a genetic predisposition and is aggravated by specific environmental triggers. Attempts to study the biochemistry of migraine began as early as the 1960s and were primarily directed at serotonin metabolism after an increase of 5-hydroxyindoleacetic acid (5-HIAA), the main metabolite of serotonin was observed in urine of migraineurs. Genetic and biochemical studies have primarily focused on the neurotransmitter serotonin, considering receptor binding, transport and synthesis of serotonin and have investigated serotonergic mediators including enzymes, receptors as well as intermediary metabolites. These studies have been mainly assayed in blood, CSF and urine as the most accessible fluids. More recently PET imaging technology integrated with a metabolomics and a systems biology platform are being applied to study serotonergic biology. The general trend observed is that migraine patients have alterations of neurotransmitter metabolism detected in biological fluids with different biochemistry from controls, however the interpretation of the biological significance of these peripheral changes is unresolved. In this review we present the biology of the serotonergic system and metabolic routes for serotonin and discuss results of biochemical studies with regard to alterations in serotonin in brain, cerebrospinal fluid, saliva, platelets, plasma and urine of migraine patients.

Culture and the evolution of obesity

Human predispositions to fatness and obesity are best understood in the context of cultural and biological evolution. Both genes and cultural traits that were adaptive in the context of past food scarcities play a role today in the etiology of maladaptive adult obesity. The etiology of obesity must account for the social distribution of the condition with regard to gender, ethnicity, social class, and economic modernization. This distribution, which has changed throughout history, undoubtedly involves cultural factors. A model of culture is presented that has advantages over an undifferentiated concept of the "environment" for hypothesis generation. Cultural predispositions to obesity are found in the productive economy, the mode of reproduction, social structure, and cultural beliefs about food and ideal body size. Cross-cultural comparison can contribute to an understanding of the prevalence of obesity in some modern affluent societies.

Changing food preference as a function of mood

The authors investigated the effect of mood on food selection. Participants (N = 98) indicated the likelihood of general eating and the likelihood of eating specific foods after reading and projecting themselves onto the events and emotions described in a sad and a happy vignette. Both men and women believed they were more likely to consume food following a happy versus a sad event, and men believed they were significantly more likely to eat than did women. However, the type of food men and women believed they would consume interacted with the type of event experienced. Vegetarian snack foods were more likely to be consumed following a happy versus a sad event, with men more likely to eat snack foods. Men did not significantly change in likelihood of consuming sweet foods as their mood changed. However, women believed they were more likely to consume sweet foods following a sad event. The authors discuss the results in terms of a self-medication hypothesis and the effect of carbohydrates on central serotonin and endogenous opioids. Overall, results demonstrated that mood influences belief in the likelihood of food selection.

Affect modulates appetite-related brain activity to images of food

OBJECTIVE

We examined whether affect ratings predicted regional cerebral responses to high and low-calorie foods.

METHOD

Thirteen normal-weight adult women viewed photographs of high and low-calorie foods while undergoing functional magnetic resonance imaging (fMRI). Regression analysis was used to predict regional activation from positive and negative affect scores.

RESULTS

Positive and negative affect had different effects on several important appetite-related regions depending on the calorie content of the food images. When viewing high-calorie foods, positive affect was associated with increased activity in satiety-related regions of the lateral orbitofrontal cortex, but when viewing low-calorie foods, positive affect was associated with increased activity in hunger-related regions including the medial orbitofrontal and insular cortex. The opposite pattern of activity was observed for negative affect.

CONCLUSION

These findings suggest a neurobiologic substrate that may be involved in the commonly reported increase in cravings for calorie-dense foods during heightened negative emotions.

Direct and indirect effects of everyday emotions on food intake of elderly patients in institutions

BACKGROUND

Decreased food intake is an important risk factor for malnutrition, which is highly prevalent among geriatric patients. The emotional nature of the hospitalization experience and the complex organizational setting involved in meal production and delivery services in institutions increase the risk for decreased food intake. Everyday emotions are known to have a particularly strong influence on decision-making and behavior in the elderly, and have also been shown, in younger populations, to influence food intake and its psychological antecedents, such as quality perception and satisfaction judgments. The objective of this paper is to study the direct impact of elderly patients' everyday emotions on food intake and their indirect effects mediated by quality perceptions and satisfaction judgments.

METHODS

Thirty patients (20 women, 10 men, 65-92 age range) in a geriatric rehabilitation unit were observed on repeated meal episodes (average of 46 care episodes per patient) where they provided self-reports for emotions (positive emotions, anger, anxiety, and mild depressed feelings), perceived meal quality, and satisfaction. Food intake was measured in terms of energy and protein content.

RESULTS

The impact on food intake was favorable, and both direct and indirect for positive emotions, direct and negative for anxiety, direct and positive for mild depressed feelings, and indirect and negative for anger. Indirect effects were mediated by quality perception judgments but not by satisfaction, which was not significantly related to food intake.

CONCLUSION

Results suggest that, given their impact on food intake, measuring and monitoring patients' everyday emotions may be an important innovative strategy to improve food intake of elderly patients in institutions.

Intake of sweet foods and counts of cariogenic microorganisms in relation to body mass index and psychometric variables in women

OBJECTIVE

As a part of the SPAWN (Stockholm Pregnancy and Women's Nutrition) study, the intake of sweet foods (habitual and pre-menstrual intakes) and the number of cariogenic microorganisms in saliva was analysed in relation to body mass index (BMI) and psychometric variables.

DESIGN

A cross-sectional study.

SUBJECTS

Three hundred and sixty-two women with a median BMI of 24.2 kg/m(2) (range 17.5-47.8) and 45 y of age (range 34-64).

METHODS

A questionnaire of sweet food intake, salivary counts of mutans streptococci and lactobacilli and a self-rating scale on psychometric variables (CPRS-S-A).

RESULTS

The number of mutans streptococci correlated with BMI (P<0.05), indirectly indicating a higher intake of sweet foods in obese women. The reported energy intake of sweet foods (more specifically the intake of chocolate), correlated with CPRS scores (P<0.01), indicating that women with more severe psychiatric symptomatology have higher intakes of sweet foods.

CONCLUSIONS

This study suggests that women with higher CPRS score have higher energy intakes of sweet foods, indicating a possible link between mood regulation and the intake of sweet food.

SPONSORSHIP

Karolinska Institute Research Funds.

A Low Protein, High Carbohydrate Diet Attenuates Alcohol Intake in Rats

To test whether a tryptophan-enhancing diet will reduce alcohol intake as serotonergic drugs do, two studies were conducted. In Experiment 1, 32 male, alcohol-drinking rats were randomly assigned to one of four isocaloric diets containing 25%-protein/65%-carbohydrate, 25%-protein/4%-carbohydrate, 4%-protein/65%-carbohydrate, or 4%-protein/4%-carbohydrate. Following a baseline week during which they ate standard lab chow, rats were offered their assigned experimental diet, water, and 5%-alcohol solution ad lib for three weeks. Alcohol and diet intakes were measured daily. In Experiment 2, 32 naive male, alcohol-drinking rats were assigned to one of the experimental diets used in Experiment 1. Following a one-week baseline, rats were offered their assigned diet, water, and 5%-alcohol/1%-sucrose solution ad lib for two weeks and then were switched back to standard lab chow for one week, with alcohol intake measured daily. Rats consuming the low protein, high carbohydrate diet drank 60-80% less alcohol than did rats offered other diets. This reduction in alcohol intake is most likely due to increased brain serotonin levels produced by the dietary manipulation.

Effects of meal composition on blood alcohol level, psychomotor performance and subjective state after ingestion of alcohol

Moderating effects of meal composition on psychomotor performance impairment and feelings after alcohol were examined in a between-subjects design. Fifty-one male volunteers fasted or received either a high carbohydrate (85% energy) or a high protein (94% energy) meal. Alcohol was administered at a dose to achieve a blood alcohol level (BAL) of 60 mg/100 ml, as a placebo. Subjects performed a dual task of primary tracking and secondary reaction time and a five-choice reaction time task. Feelings were also assessed by rating. The high carbohydrate meal reduced BAL at peak and 2 h after drinking, but a high protein meal had no significant effect. Although performance was impaired by alcohol, neither meal significantly reduced impairment and there was no effect of meal type on performance in the placebo condition. However, alcohol increased rated intoxication and the high carbohydrate meal reduced this effect. Subjects who had consumed high protein meals had more negative affect 2 h after alcohol than did subjects who had consumed high carbohydrate meals or fasted. It is concluded that there is only a weak relationship between BAL and performance impairment and food has only limited effects on impairment, although it reduces BAL.

Food craving during the menstrual cycle and its relationship to stress, happiness of relationship and depression; a preliminary enquiry

The associations between retrospective ratings of food craving and depression during the premenstrual, menstrual and postmenstrual phases of the preceding menstrual cycle and ratings of current levels of stress and happiness of relationship were examined in 5,546 women. In each phase examined, the severity of food craving was very strongly related to the reported severity of depression. Overall levels of food craving were inversely related to happiness of relationship and there was some interaction of this effect with on-going stress. However, once the effect of depression was accounted for there was no effect of either current stress or happiness of relationship on the cycle-related pattern of food craving and in general the magnitude of the effect of these psychosocial variables was very small compared with that of depression. Food cravings were also reported in the absence of depression, tending to show a cycle-related pattern, maximal premenstrually, declining during menstruation and further postmenstrually. Whilst this is consistent with a cycle-related biological explanation, it remains unclear whether the striking amplification of food craving ratings in association with co-existing depression, in all three phases examined, is also biologically based or dependent on psychological mechanisms. In view of the retrospective nature of the ratings of mood and craving and the limited assessment of stress and happiness of relationship, these findings should be regarded as preliminary. They are, however, of potential importance and the association between these two common phenomena deserves further study.

Overview: biological processes relevant to drugs of dependence

Key points are highlighted from five papers that address biological processes underlying the actions of opiates, CNS stimulants, nicotine, alcohol, and benzodiazepines. It is noteworthy that: (1) positive and negative reinforcement are common processes underlying actions of drugs of dependence; (2) dopaminergic systems in the ventral tegmental area of the brain seem to be involved in the positive reinforcement of drugs of dependence; (3) GABA also may be involved in this positive reinforcement; (4) receptor sensitization and desensitization may be involved in the actions of drugs of dependence; (5) noradrenalin, 5-HT, ACh, NMDA and corticosteroids also may be involved in drug dependence; (6) motivational systems and processes in addition to positive and negative reinforcement deserve increased research attention; and (7) there may be genetic-based individual differences in drug dependence processes.

[The effect of tryptophan on the regulation of food intake in normal and overweight persons]

The neurotransmitter serotonin significantly contributes to the regulation of food intake and appetite behaviour. The cerebral serotonin synthesis depends on the availability of the precursor tryptophan. To examine how diets with different carbohydrate, protein and tryptophan content affect food preferences and the mood, healthy obese and non-obese male adults consumed the following isocaloric diets at breakfast: standard diet (60% carbohydrate), protein-rich diet (35% carbohydrate, 40% protein), carbohydrate-rich diet (80% carbohydrate), tryptophan supplemented diet (standard diet + 1.5 g tryptophan). The plasma concentration of tryptophan (TRP) and large neutral amino acids (LNAA) is determined by their uptake with the diet. In obese and non-obese adults the TRP/LNAA-quotient rose significantly by upto 0.40 to 0.57, following the tryptophan supplemented breakfast. The protein-rich diet reduced the TRP/LNAA-quotient. The preference of protein-rich food after the consumption of carbohydrate-rich diets (60-80% carbohydrate) was diagnosable with the non-obese person and not with the obese person. No obvious connection was detected between nutrient preferences and plasma TRP/LNAA-quotient. There was no influence of the plasma TRP/LNAA-quotient after meals with different nutrient relation on mood. Therefore it is concluded that different carbohydrate and protein content and also additional tryptophan supplementation of single meals is not able to modify the brain serotonin synthesis and release in healthy people in a kind that serotonin induced behaviour would be changed, at least on a short time basis.

Heat-loss response to a thermal challenge in seasonal affective disorder

This study extends earlier findings of poorly facilitated postexercise heat loss during the winter in seasonal affective disorder (SAD). While depressed in the winter, 19 SAD subjects exhibited a significantly impaired postexercise heat loss relative to 10 control subjects. During the summer while euthymic, SAD subjects did not significantly differ from control subjects in postexercise heat loss. Since thermoregulatory heat loss is a highly dopamine-dependent process, these results support earlier findings of poorly facilitated dopamine availability in SAD during the winter and suggest a centrally mediated effect of light in SAD.

D2 dopamine receptor gene and obesity

The prevalence of Taql A D2 dopamine receptor (DRD2) alleles was determined in 73 obese women and men. In this sample with a mean body mass index of 35.1, the A1 (minor) allele of the DRD2 gene was present in 45.2% of these nonalcohol, nondrug abusing subjects. The DRD2 A1 allele was not associated with a number of cardiovascular risk factors examined, including blood lipids (cholesterol, high-density lipoprotein [HDL]- and low-density lipoprotein [LDL]-cholesterol, and triglycerides). However, phenotypic factors characterized by the presence of parental history and postpuberty onset of obesity as well as carbohydrate preference were associated with obese subjects carrying the A1 allele. The cumulative number of these three factors was positively and significantly (p < .0002) related to A1 allelic prevalence. The data showing an association of the minor allele of the DRD2 gene with phenotypic characteristics suggest that this gene, located on q22-q23 region of chromosome 11, confers susceptibility to a subtype of this disorder.

Regional distribution of serotonin and substance P co-existing in nerve fibers and terminals in the brainstem of the rat

Two-color fluorescence immunohistochemistry was used to identify and map the distribution of nerve processes immunoreactive for both serotonin and substance P in the rat brainstem. Doubly labeled fibers were observed throughout the brainstem, but tended to be densest in cranial nerve motor nuclei and in reticular regions of the ventral medulla. In the trigeminal motor nucleus, the facial nucleus and the spinal accessory nucleus, the majority of serotonergic varicosities also appeared to contain substance P; in the occulomotor nucleus and the hypoglossal nucleus the numbers of double-labeled and single-labeled serotonergic varicosities were roughly equal. Thus, co-existence of substance P with serotonin was common in many cell groups innervating skeletal muscle. The proportion of double-labeled varicosities was significantly lower in the nucleus of the solitary tract, wherein single-labeled varicosities were much more common. Double-labeled fibers and varicosities were also significantly less common in the spinal trigeminal nucleus. In addition, double-labeling appeared to be uncommon in regions involved in the processing of special sensory information (e.g. auditory, vestibular and visual pathways). These results demonstrate a subpopulation of serotonergic fibers immunoreactive for substance P in the brainstem of the rat. The consistently high density of double-labeled processes in cranial nerve motor nuclei suggests that, as may be the case in the spinal cord, neurons containing serotonin and substance P regulate the activity of motoneurons that innervate skeletal muscle. In addition, they may be involved in other aspects of the function of the brainstem.

Protein and carbohydrate selection respond to changes in dietary saturated fatty acids but not to changes in essential fatty acids

We previously reported differences in protein and carbohydrate selection patterns in post-weanling rats fed beef tallow or soybean oil-based diets. Two experiments were designed to determine the characteristic of the dietary fat which mediates the selection behavior. For each experiment, dietary fat was 20% (w/w) of diets and fatty acid profiles were obtained by blending fat sources. Rats were randomly assigned to diets (24% protein, 40% carbohydrate) which varied only in fatty acid composition. After 2 weeks, rats selected from 2 diets with the fat composition previously fed, but varying in their protein and carbohydrate composition (55% protein, 4% carbohydrate and 5% protein, 61% carbohydrate). Experiment 1 was designed to test the effect of relative (omega 6: omega 3 ratios of 1 and 20) and absolute (15% or 4% omega 6, 0.7% or 0.2% omega 3) differences in essential fatty acids on macronutrient selection patterns. Differences in dietary essential fatty acids had no effect on energy intake or the proportion of energy consumed as protein and carbohydrate. Experiment 2 examined the effect of differences in the level of saturated fat (3-10% diet (w/w] on protein and carbohydrate selection. Animals selecting from diets with higher levels of saturated fat consumed more energy as protein and less as carbohydrate than rats selecting from diets with lower levels of saturated fat (p less than 0.0001). Regression analysis was used to examine the relationship between percent protein or carbohydrate energy and classes of dietary fat. The strongest relationship existed between percent dietary saturated fat and percent protein or carbohydrate energy (p less than 0.0001). Polyunsaturated:saturated fat ratio was also weakly associated with percent protein and carbohydrate energy (p less than 0.05). Polyunsaturated, monounsaturated, omega 6 and omega 3 fatty acids were not significantly related to percent protein or carbohydrate energy. These results indicated that protein and carbohydrate selection patterns are altered in response to qualitatively different dietary fatty acids, and that the amount of saturated fat in the diet is the important characteristic of dietary fat mediating the behavioral alteration.