initial flaking of the squash seeds is done to rupture oil cells and to prepare a thin flake with a large surface area for pre - pressing by passing seeds through a set of smooth rollers using a lab scale flaking mill . conditioning is done to further rupture oil cells , increase pliability of the flakes and increase the efficiency of the expeller by lowering the viscosity of the oil contained . the conditioning of the flaked seeds was undertaken in a microwave for from about 1 minute to about 2 minutes to achieve a temperature between 40 - 45 ° c . the heated seeds are then pressed using a mechanical press ( gusta laboratory press set to 4 . 5 amps ) to remove approximately ⅔ oil with 22 % by weight residual oil content in the press cake . with pure protein or peptides , amino acid determination is relatively easily made with high pressure liquid chromatography ( hplc ). hplc requires the hydrolysis of protein into the constituent amino acids that are then run in a column under pressure . the column causes the various amino acids to run at different speeds dependent on the size and charge . the determination of a tryptophan within a food source is , however , more complicated because of its ability , especially in the peptide form , in the presence of light , heat , hydrogen and hydroxyl ions ( concon , 1975 ). this difficulty may explain , in part , the problems in quantifying tryptophan within food in a reliable fashion utilizing hplc with possible tryptophan losses of 10 - 30 % ( landry and delhaye , 1996 ). relying on the presence of an aromatic ring within the tryptophan molecule , a spectrophotometric method was utilized at the guelph food technology centre that allowed for the reliable quantification of tryptophan ( balestrierl et al ., 1978 ). the quantitative determination of aromatic amino acids in proteins is possible with second derivative spectroscopy , an analysis of the ultraviolet absorption spectra within a certain wavelength . derivative spectroscopy is superior to direct spectroscopy through the elimination of spectral interference . in the case of tryptophan , direct spectroscopy produces a sloping background absorbence . second derivative spectroscopy eliminates any background absorbence allowing the tryptophan absorbence to be quantified at a wavelength of approximately 280 nm . pumpkin seeds , butternut squash seeds and peppercorn squash seeds were flaked , conditioned and pressed according to the procedure set forth in example 1 . using second derivative spectroscopy , the tryptophan content of the seed meal was determined and the results set forth in the table below . screening of butternut squash , peppercorn squash and pumpkin seeds revealed that all have high tryptophan contents but that butternut squash seeds are highest in tryptophan . it also revealed that 100 gm of defatted butternut squash seed meat contains in excess of 1000 mg of tryptophan . for butternut squash , the ratio of seeds to the fmal seed meal is approximately one third . hplc analysis on partially dehulled and partially defatted butternut squash seeds are as follows : tryptophan content of food is typically determined with high pressure liquid chromatography ( hplc ) in which the protein undergoes base hydrolysis into its constituent amino acids over several hours . in the context of food analysis this methodology can lead to a 10 - 30 % loss of tryptophan ( landry and delhaye 1996 ). to avoid this potential problem second derivative - spectroscopy , a method to screen various seeds without the need for protein hydrolysis at high temperatures over prolonged periods ( balestrierl et al 1978 ) was used . the results of these tests revealed that seed of the butternut squash contains more tryptophan than any other reported food source . in fact , the protein portion of the seed contains 25 mg of tryptophan per 1 g of protein . since hplc is the industry standard , a sample of defatted butternut squash seeds was analyzed with hplc after naoh hydrolysis in an argon environment . the high content of tryptophan in these seeds was determined , although the predicted loss of some tryptophan with hydrolysis was also confirmed . the concentration of tryptophan was sufficient to provide a plant - based functional food that acts as a natural source of central nervous system ( cns ) tryptophan . a three arm study was run in parallel with subjects randomly assigned to one of three groups , namely ( a ) a food rich in defatted squash meal in combination with a carbohydrate ; ( b ) a food enriched with pharmaceutical grade tryptophan and a carbohydrate ; and ( c ) a placebo food rich in a carbohydrate with minimal protein . both the subject and the research nurse who conducted the study were blind to the assignment of each subject . the subjects met the nurse on a weekly basis in order to turn in their sleep scores and review any side effects from that week and to receive the sleep diary for the next week . food1 was prepared in a 7 day lot according to the following amounts : food2 was prepared in a 7 day lot according to the following amounts : food3 was prepared in a 7 day lot according to the following amounts : week 1 allowed for a baseline measurement of sleep parameters as determined by a structured sleep diary ( morin 1993a ). sleep parameters measured included total time awake each night , total sleep time each night , total time in bed each night , sleep efficiency ( total sleep time / total time in bed × 100 ). subjects completed a sleep quality assessment as determined by the sleep impairment index ( morin 1993b ) at the beginning and end of the first week . they also recorded their previous nights sleep patterns every morning in the structured sleep diary . in week 2 , defined as the treatment week , each subject ingested food1 , food2 or food3 depending on their assignment , one hour prior to bed . subjects continued to report their sleep in the structured sleep diary each morning and again completed the sleep impairment index at the conclusion of the week . week 3 , each subject continued to record their sleep each morning in the structured sleep dairy but in the absence of the assigned food . at the conclusion of week 3 and the study , they again completed the sleep impairment index . criteria for selection included men and women over the age of 18 experiencing trouble falling asleep or staying asleep three or more nights / week for a duration of three months . exclusion criteria included heart disease , pregnancy , food allergies , diabetes , sleep apnea , and shift workers . a sample of volunteers was selected from perth county region , ontario , canada . one hundred and fifty eight ( 158 ) subjects were recruited through letters to family doctors , newspaper and radio advertisement . fifty - one subjects were rejected after a short ( approximately 10 minute ) structured telephone interview indicating evidence of health issues , medication or lack of desire to commit to the three week protocol . a further 50 subjects were rejected after a detailed structured personal interview with a research nurse for the following reasons : health ( 20 ); failure to appear for the interview ( 3 ); medication contraindicated with tryptophan ( 12 ), unwillingness to stop sleep medications ( 3 ), food allergies ( 5 ), unwillingness to commit to three week protocol ( 3 ), shift workers ( 3 ), inability to meet criteria for insomnia ( 1 ). after initiation into the study , seven subjects failed to complete the protocol for the following reasons : time commitment ( 1 ), failure to attend weekly interviews ( 1 ), death of close family member ( 1 ), relationship stress ( 1 ), nausea ( 1 food1 , 2 placebo ). all subjects were assessed by the following : brief symptom inventory ( bsi ), a medical and psychiatric interview , and laboratory tests as deemed necessary by the principal investigator ( i . e . blood tests , urinalysis , ekg etc ). all subjects were informed about the purpose , risks and benefits associated with the study . written , signed consent was obtained and a copy given to the participant . subjects were asked to abstain from the use of alcohol , during the entire three week study . they were instructed to limit their caffeine intake and to maintain a regular sleep wake schedule during this period . ethical approval was given from the ethics committee of the stratford general hospital . coincidentally two identical twin brothers enrolled in the study apparently unaware that each other had also enrolled . these twin subjects were randomly assigned to one of the two treatment conditions of food1 and food2 . their data is included in the grouped data but was also analyzed separately . the twin brothers were 56 years old , of similar weight ( 68 . 2 vs . 70 . 5 kg ) and in good physical health . both identified significant difficulties with initiating and maintaining sleep of a long - standing duration . for a preliminary study a total of 29 subjects ( 22 females , 7 males ) were randomly assigned to one of three treatment conditions : food1 , defatted butternut squash seed meal in combination with glucose , vitamin b3 and b6 ; food2 , 220 mg of pharmaceutical grade tryptophan in a food rich in carbohydrate ( including an equivalent amount of glucose contained in food1 ), vitamins b3 and b6 with ; food3 ( placebo ), carbohydrate with a trace amount of protein . the average ages ( 52 . 1 , 49 . 5 and 54 . 4 years , respectively ) did not differ significantly between groups . the average weight ( 72 . 3 , 67 . 1 and 72 . 9 kg .) did not significantly differ between groups . in a second study ( which incorporated data from the preliminary analysis ) a total of 50 subjects ( 38 females , 12 males ) were randomly assigned to one of three treatment conditions described above : food1 , food2 and placebo , carbohydrate with a trace amount of protein . the average ages ( 53 . 3 , 52 . 1 , 50 . 1 years ) did not differ significantly between groups . the average weight ( 71 . 0 , 71 . 6 , 71 . 8 kg .) did not significantly differ between groups . a multivariate analysis of variance ( manova ) with 3 between factors ( food 1 , food2 and placebo ) and 3 within factors ( week1 - baseline , week2 - treatment , and week3 - post - treatment ) did not result in any significant interactions in the preliminary analysis of 29 subjects . significant differences , however , were noted between baseline and treatment weeks in the following sleep parameters : sleep efficiency , total wake time and total sleep time . these differences are summarized in the tables 3 , 4 and 5 below . the same 3 × 3 manova when performed on data from the 50 subjects resulted in a week ( baseline , treatment , post - treatment ) by condition ( food1 , food2 , placebo ) interaction ( p = 0 . 03 ). post hoc analyses revealed that this interaction resulted from a significant reduction in total time in bed in week2 ( treatment week ) for those treated with food1 in contrast to an increase in time in bed during the treatment week for food2 and placebo . total time in bed measures the time from bedtime to rising time and includes time to fall asleep , time asleep , time awake during the night and time waiting in bed after awaking but before rising . as described above subjects treated with food1 had a significant reduction in total time in bed in contrast to an increase for food2 and placebo . the differences in total time in bed their significance are recorded in table 1 . further analyses suggest that this difference may result from the fact that those subjects treated with food1 had a more continuous block of sleep . therefore , sleep interruption time , a sleep parameter specific to the determination of a continuous block of sleep , was analyzed in addition to other sleep variables which were included in the preliminary study : sleep efficiency , total wake time and total sleep time . sleep interruption time measures the amount of time awake during the night as the result of an interrupted sleep pattern . the results indicate that there is a significant reduction ( average reduction of 23 minutes / night ) in time lost due to sleep interruptions for those treated with food1 which was significantly different from baseline ( p = 0 . 006 ) as well as the placebo ( p = 0 . 04 ). those subjects treated with food2 also had a reduction of 15 minutes which was different from baseline ( p = 0 . 003 ) but not placebo . the results are summarized in table 2 . in a preliminary study ( n = 29 ), during the treatment week , the squash ( food1 ) decreased the total wake time by 41 minutes / night on average ( p = 0 . 011 ) which was greater than the food enriched with pharmaceutical grade tryptophan ( food2 ) which decreased the total wake time by 30 minutes ( p = 0 . 040 ). the carbohydrate placebo ( food3 ) decreased the wake time by 5 minutes which was not statistically significant ( p = 0 . 760 ). in the post - treatrnent there was only a modest further reduction in each group which was not significantly significant . table 3 summarizes the change in total wake time . in the complete study , during the treatment week , the squash ( food1 ) decreased the total wake time by 30 minutes / night on average ( p = 0 . 008 ) whereas the food enriched with pharmaceutical grade tryptophan ( food2 ) also decreased the total wake time from baseline by 35 minutes ( p = 0 . 003 ). the carbohydrate placebo ( food3 ) decreased the wake time by only a marginal amount ( 7 . 5 minutes ) which was not statistically significant ( p = 0 . 523 ). the advantage of the food1 and food2 treatment is lost in the post - treatment week . table 3a summarizes the change in total wake time . in a preliminary study , during the treatment week both the squash ( food1 ) and the food enriched with pharmaceutical grade tryptophan ( food2 ) improved sleep efficiency . squash ( food1 ) increased sleep efficiency by 8 %/ night ( p = 0 . 013 ) whereas the food enriched with pharmaceutical grade tryptophan increased by 5 %/ night ( p = 0 . 047 ). the carbohydrate placebo ( food3 ) also increased sleep efficiency by only 1 % ( p = 0 . 749 ). in the post - treatment when all three groups were no longer eating an experimental food , advantage of both squash and pharmaceutical grade tryptophan was lost . table 4 summarizes the comparisons of sleep efficiencies . in a complete study , during the treatment week both the squash ( food1 ) and the food enriched with pharmaceutical grade tryptophan ( food2 ) improved sleep efficiency . squash ( food1 ) increased sleep efficiency by 5 %/ night ( p = 0 . 019 ) whereas the food enriched with pharmaceutical grade tryptophan increased by 8 %/ night ( p = 0 . 002 ). the carbohydrate placebo also increased sleep efficiency by only 2 % ( p = 0 . 369 ). table 4a summarizes the comparisons of sleep efficiencies . in the preliminary study the total sleep time was increased across all three conditions but especially so in those subjects treated with food1 and food2 . only those treated with food2 actually had a statistically significant increase in sleep time ( p = 0 . 04 ) although the increase in sleep time in those treated with food1 approached statistical significance ( p = 0 . 066 ). the increase in sleep time in those treated with placebo did not approach statistical significance ( p = 0 . 520 ). these results are summarized in table 5 . in a complete study the results paralleled those of the preliminary study . those subjects treated with food2 had a statistically significant increase in sleep time during the treatment week and those treated with food1 had an increase that approached statistical significance . these results are summarized in table 5a . subjects recorded their subjective response based on a weekly report of the sleep impairment index . a seven - point questionnaire self - rating scale analyzed various aspects of insomnia and its impact on daily function . eleven of 18 subjects ( 61 %) treated with food1 reported less concern about their sleep after one week of treatment in comparison to 6 of 17 subjects treated with food2 ( 35 %) and 5 of 15 subjects treated with placebo ( 33 %). the overall perception of one &# 39 ; s state upon waking each morning was also measured on a daily basis . this question assessed their overall perception of their waking state on a three - point scale , with 1 as ‘ exhausted ’ and 3 as ‘ refreshed ’. those subjects treated with the squash - based food ( food1 ) reported a highly significant improvement . these differences and their significance are summarized in table 6 . the identical twin in the squash ( food1 ) treatment outperformed his sibling treated with pharmaceutical grade tryptophan ( food2 ) on both a reduction of total wake time as well as increased sleep efficiency throughout the study . a sample size of two does not allow statistical analysis so graphs of outcome are included instead with trend lines included . the most apparent differences occurred in total sleep time wherein the twin on squash food more than doubled his sleep efficiency over the course of the study . the twin treated with pharmaceutical grade tryptophan per se increased his sleep efficiency by less than 30 %. increases in sleep efficiency paralleled the increases in total sleep time . the twin treated with the squash based food more than doubled his total nightly sleep whereas as his twin treated with pharmaceutical grade tryptophan increased his total nightly sleep by less than 35 %. further studies were carried out which measured not only the actual parameters of sleep disturbance but also the impact of insomnia on daily lives . the subjective and objective measures that resulted in significant results are described below . a subset of subjects was drawn to ingest defatted squash seed meal without any other additive . after the conclusion of their 21 - day original trial , each if these subjects underwent a 4 - week washout period . at the conclusion of the washout period each subject was given 22 gm of defatted squash seed meal / night with instructions to follow the original protocol ( eat experimental food 1 hour prior to bedtime , following the sleep pattern described above , avoidance of protein in the evening meal etc .). one subject was excluded after she reported adding a carbohydrate to the defatted meal despite instructions to the contrary . the remaining number was too small to allow for valid statistical analysis but there was an overall reduction in average total wake time ( 114 . 7 mins , baseline vs . 59 . 7 mins with defatted meal ), an increase in total sleep time ( 385 . 4 mins , baseline vs . 411 . 7 with defatted meal ) and an increase in sleep efficiency ( 76 . 5 % baseline vs . 87 % with defatted meal ). the apparent superior performance of food1 based on squash seed defatted meal is , indeed , surprising . in fact , previous experiments would suggest that the plant protein should have resulted in an inferior performance to the combination of pharmaceutical grade tryptophan and carbohydrate . in a seminal study of diet and brain tryptophan levels , fernstrom and wurtman ( 1972 ) fed six groups of rats one of six meals prior to their sacrifice : ( i ) diet 1 , carbohydrate meal ( ii ) diet 2 , diet 1 supplemented with 18 percent casein , dry weight ( iii ) diet 3 , diet 1 supplemented with an artificial amino acid similar to casein in amino acid content , 18 percent dry weight ( iv ) diet 3 , minus tyrosine , phenylalanine , leucine , isoleucine , and valine . groups of rats were killed 1 or 2 hour postprandial to determine plasma tryptophan , brain tryptophan and brain serotonin levels . subsequent analysis demonstrated that although protein meals result in a significant rise ( 60 - 70 %) in plasma tryptophan there was no significant increase in brain tryptophan or serotonin . further study of an additional two groups of rats ( one fed diet 3 with the complete amino acid mixture versus another fed diet 3 with a complete amino acid mixture minus tyrosine , phenylalanine , leucine , isoleucine and valine ) found a significant increase in brain tryptophan occurred only in the diet minus the competing neutral amino acids . although the time course to sacrifice was relatively short in the fernstrom and wurtman &# 39 ; s experiment , a later experiment ( fernstrom et al . 1985 ) sacrificed rats every 4 hours postprandial over a 24 hour period and also failed to find any significant increase in brain tryptophan at any point in a 24 cycle after the ingestion . in this later experiment some rats were fed significant quantities in protein ( maximum of 40 % protein diet ) which lead to significant increases in serum tryptophan but no change in brain tryptophan levels . investigations in non - human primates parallel those findings from rat studies in that conditions that favour increased ratio of serum tryptophan / competing amino acids results in increased brain tryptophan . leathwood and fernstrom ( 1990 ) demonstrated a dose - dependent increase in tryptophan in subcortical regions of the brain , in concert with a dose - dependent reduction in competing amino acids , when groups of adult cynomolgus monkeys were fed various combinations of carbohydrate ( maltodextrin ) and one of three amounts of synthetic tryptophan ( 20 mg / kg , 90 mg / kg and 400 mg / kg ). thus , a fair and thorough review of the literature would predict the superiority of pharmaceutical grade tryptophan per se combined with carbohydrate over placebo and squash meal . the present squash seed food formulation contains defatted meal which is rich in protein and therefore should not result in equivalent or superior sleep based upon previous animal studies . similarly , the defatted meal alone appears beneficial which again is not obvious based upon the previous literature since defatted meal is approximately 47 % protein by weight and less than 15 % carbohydrate . the previous literature would predict the clear advantage pharmaceutical grade tryptophan in combination carbohydrate in the improvement of sleep . the fact that defatted seed meal is superiour to pharmaceutical grade tryptophan is surprising and may reflect differences in human brain function in comparison to other mammalian brains ( both primate and non - primate ), some beneficial effect in the ingestion of a protein rich in the tryptophan precursor , or some other metabolic advantage . it may also be concluded that either other amino acids in the protein actually assist in sleep enhancement or some other aspect of protein ingestion in humans affects the transmission of tryptophan across the blood - brain - barrier in a way not predicted by ratio of serum tryptophan to other competing amino acids . betz a . l . and goldstein , g . w ., science , 202 : 225 - 227 ( 1978 ). balestriel , c ., et al ., european journal of biochemistry , 90 : 433 - 440 ( 1978 ). fears , r ., and murrell , f . a ., british journal of nutrition , 43 : 349 - 356 ( 1980 ). fernstrom , j . d . and wurtman , r . j , science , 174 : 1023 - 1025 ( 1971 ). kotake , y . and murakami , e ., american journal of nutrition american journal of clinical nutrition , 24 : 826 - 829 ( 1971 ). lajtha , a ., in aromatic amino acids in the brain ( ciba foundation symposium 22 ) new york : american elsevier pp . 25 - 49 ( 1974 ). saunders , n . r ., et al ., clinical and experimental pharmacology and physiology , 26 : 11 - 19 ( 1999 ). thomas , j . m . and rubin , e . h ., american journal of psychiatry , 141 : 281 - 283 ( 1977 ). balestrierl c , colonna g , giovans a , irace g , servillo l l ( 1978 ) second - derivative spectroscopy of proteins : a method for the quantitative determination of aromatic acids in proteins european journal of biochemistry 90 : 433 - 440 fernstrom j d wurtman r j ( 1972 ) brain serotonin content : physiological regulation by plasma neutral amino acids . science 178 : 414 - 6 fernstrom j d fernstrom m h grubb p e volk e a ( 1985 ) absence of chronic effects of dietary protein content on brain tryptophan concentrations in rats . journal of nutrition 115 : 1337 - 44 griffiths w j , lester b k , coulter j d , williams h l ( 1972 ) tryptophan and sleep in young adults . psychophysiology 9 : 345 - 356 hartmann e ( 1982 ) effects of l - tryptophan on sleepiness and on sleep . journal of psychiatric research . 17 : 107 - 13 hartmann e , spinweber c l ( 1979 ) sleep induced by 1 - tryptophan . effect of dosages within the normal dietary intake . journal of nervous and mental disease 167 : 497 - 9 landry j , delhaye s ( 1996 ) tryptophan content of foods and feeds . advances in experimental medicine and biology 398 : 703 - 9 leathwood p d fernstrom j d ( 1990 ) effect of an oral tryptophan / carbohydrate load on tryptophan , large neutral amino acid and serotonin and 5 - hydroxyindoleacetic acid levels in monkey brain . journal of neural transmission — general section 79 : 25 - 34 morin , c . m . ( 1993a ) appendix f : sleep diary . in : insomnia , psychological assessment and management . guilford press , new york , pp 209 - 211 morin , c . m . ( 1993b ) appendix b : sleep impairment index . in : insomnia , psychological assessment and management . guilford press , new york , pp 199 - 200 schneider - helmet d , spinweber c l ( 1986 ) evaluation of 1 - tryptophan for treatment of insomnia : a review . psychopharmacology 89 : 1 - 7 although this disclosure has described and illustrated certain preferred embodiments of the invention , it is to be understood that the invention is not restricted to those particular embodiments . rather , the invention includes all embodiments which are functional or mechanical equivalence of the specific embodiments and features that have been described and illustrated .
compositions are described comprising at least partially defatted meal from a plant source containing protein - bound tryptophan , preferably squash seeds , and , optionally , a carbohydrate source provided in an amount capable of facilitating transport of in vivo generated tryptophan across the blood brain barrier . also described are dietary supplements , foods and beverages comprising the composition of the invention to induce sleep or provide tryptophan supplementation to individuals in need thereof .