a number of preferred embodiments of the invention , were performed in order to demonstrate that treatment with fatty acid compositions , comprising at least one of epa and dha or any combinations thereof , reduces body weight and / or prevents gain in body weight . in a first preferred embodiment , the effects of an omega - 3 fatty acid composition containing about 20 % epa and 50 % dha ( weight ratio ), on body weight was studied . in a second preferred embodiment , the effect of the dose of an omega - 3 fatty acid composition , rich in dha , ( herein represented as a fatty acid composition comprising about 20 % epa and 50 % dha ) in relation to body weight reduction was studied . in a third embodiment of the invention , potential differences in effects between a dha - enriched omega - 3 product , an epa - product and plant oils containing omega - 6 fatty acids , were studied . in the fourth and fifth embodiment of the invention , potential differences in effect between only a dha - enriched and epa - enriched omega - 3 product , were studied . in a sixth embodiment of the invention , the effect of an omega - 3 fatty acid composition on prevention of obesity and body weight gain , was studied . finally , in the seventh study , weight reduction under the condition of developing obesity and additive effects between calorie restriction and an omega - 3 fatty acid composition , were evaluated . seventh different experiments were performed on mice to investigate various treatments for reducing body weight and / or for preventing body weight gain . in study 1 - 5 adult male mice ( c57bl / 6j mouse ) were randomly assigned different types of semi synthetic high - fat diets where the fat components in respectively study was modified . in the two last studies adult male mice ( c57bl / 6j mouse ) were randomly assigned to a obesity - promoting hf ( high fat ) diet ( 35 % wt / wt total lipid content ) were the fat components was modified . in the first study , the effects of an omega - 3 fatty acid composition containing epa and dha on the body weight were studied . a mixture containing approximately 20 % epa and 50 % dha was used . groups ( n = 7 ) of adult male mice ( c57bl / 6j mouse ) fed standard feeding diet ( 4 % fat ), were randomly assigned one of four different types of semi synthetic high - fat ( 20 % fat ) diets where the fat component was : group 1 ) lard ( l ), group 2 ) lard plus epax2050tg ( l + fo : epax 2050tg formed 44 % w / w of total lipid content ), group 3 ) flaxseed oil ( 18 : 3n - 3 forms about 50 % of total lipids ; ln ) and group 4 ) flaxseed plus epax2050tg ( ln + fo ; epax 2050tg formed 44 % w / w of total lipid content ). note that fo herein means various epa and dha concentrates ( for instance epax high in dha versus epax high in epa ) used in these studies . the animals were fed the different diets mentioned above during 1 month and the composition of the feeding containing flaxseed oil with ( ln + fo ) or without epax2050tg ( ln ) is shown in fig1 a . after the study , the total body weight was reduced in group 2 ( l + fo ) vs . group 1 ( l ); and group 4 ( ln + fo ) vs . group 3 ( ln ), and the difference was statistically significant in group 4 vs . 3 , as evident from fig1 b . the body weights of mice before treatment were similar in all the groups . the mice &# 39 ; s given flaxseed oil plus epax2050tg had decreased by about 10 % in body weight compared to the mice &# 39 ; s only given flaxseed oil . this study shows that treatment with a fatty acid composition containing epa and dha , wherein the amount of dha ≧ epa , leads to weight reduction . in the second study the effect of the dose of an omega - 3 fatty acid composition comprising a combination of epa and dha ( approximately 20 % epa and 50 % dha ) in relation to reduction on body weight was studied . groups ( n = 7 ) of adult male mice by standard chow diet ( 4 % fat ), were randomly assigned one of three different semi synthetic high - fat ( 20 % fat ), for two months . in this experiment group 1 ) was given flaxseed oil ( ln ), group 2 ) flaxseed oil plus a higher dose of epax2050tg ( ln + fo ; epax2050tg formed 44 % w / w of total lipid content ), and group 3 ) flaxseed oil plus a lower dose of epax2050tg ( ln + fo low ; epax 2050tg formed 15 % w / w of total lipid content ), as the fat component herein . the composition of the diets containing only flaxseed oil ( ln ) and flaxseed oil with a higher ( ln + fo ) respectively a lower ( ln + fo low ) dose of epax2050tg is shown in fig2 a . at the end of the study the total body weight was reduced only in group 2 , the group given flaxseed oil with a higher dose of epax2050tg , as evident from fig2 b . the results of the second study are consistent with the first one , with weight reduction in the group given a fatty acid composition wherein the weight ratio of dha ≧ epa . moreover , the results from the present study also shows that administration of a fatty acid composition rich in dha in very low doses did not resulting significant decrease of body weight in rats fed a high fat diet . in this study potential differences in effects between a dha - enriched omega - 3 product ( herein presented as a fatty acid composition comprising approximately 10 % epa and 50 % dha ( epax1050tg concentrate ), an epa product ( rich in epa , herein presented as a fatty acid composition comprising about 45 % epa and 10 % dha ; epax4510tg ) and plant oils containing omega - 6 fatty acids , were studied . groups ( n = 7 ) of adult male mice ( c57bl / 6j mouse ), fed standard chow diet ( 4 % fat ), were randomly assigned one of six different types of semisynthetic high - fat ( 20 % fat ) diets where the fat component was : group 1 ) flaxseed oil ( plant omega - 3 ) ( ln ), group 2 ) corn oil ( plant omega - 6 ) ( k ), group 3 ) epax 1050 ( high in dha ) ( d ), group 4 ) epax 4510tg ( high in epa ) ( e ), group 5 ) corn oil + epax 1005tg ( k + d ), and group 6 ) corn oil + epax 4510tg ( k + e ). one control group maintained on standard diet (− st ) was also included . the animals were fed the different diets during 2 months . the composition of diets are shown in fig3 a and 3b . as can be seen in fig3 c , the food consumption was about 70 kj per day and animal during the 8 weeks of treatment . the results in fig3 d show that treatment with a fatty acid composition containing at least epa and dha or combinations thereof leads to weight reduction . weight reduction has been obtained in animals fed epax 1050tg ( a fatty acid composition rich in dha ) but less with epax 4510tg ( a fatty acid composition rich in epa ) in addition ( 44 % of total fat content formed by the product ) to corn oil . however , the effect of epax 1050tg ( high in dha ) was stronger compared with epaxtg 4510 . moreover , the body weights of the mice fed corn oil plus epax 1050tg ( high in dha ) had decreased by about 15 % in weight . the animals do not tolerate high - fat ( 20 %) semisynthetic diet containing only epax 1050tg ( high in dha ) as the only lipid constituent . only 1 out of 7 mice fed epax 1050tg survived longer than 4 weeks on the diet . the mice &# 39 ; s got to slimy . all of the mice fed only epax 4510tg containing diet survived but looked unhealthy . the results of the third study shows that the weight lowering effect of a fatty acid composition comprising about 10 % epa and 50 % dha ( a fatty acid composition rich in dha ), was stronger compared to a fatty acid composition comprising about 45 % epa and 10 % dha ( rich in epa ). furthermore , weight reduction due to corn oil was similar to the reduction due to a fatty acid composition comprising about 20 % epa and 50 % dha in flaxseed oil ( in the 1 st and the 2 nd experiment ) and stronger than the reduction due to a fatty acid composition comprising about 20 % epa and 50 % dha in lard ( in the 1 st experiment ) once more above states a best mode using a product rich in dha , preferably dha ≧ epa . these results also suggest a specific weight - lowering effect of an omega - 3 product of marine origin as compared with plant oils ( both omega - 3 and omega - 6 ) and saturated fats ( lard ). study 4 : effects of a fatty acid composition rich in epa versus a fatty acid composition rich in dha on weight reduction in this study , potential differences in effects between a dha - enriched omega - 3 product ( herein presented as a fatty acid composition comprising approximately 10 % epa and 50 % dha ( epax1050tg concentrate )) and an epa product ( rich in epa , herein presented as a fatty acid composition comprising about 45 % epa and 10 % dha ; epax4510tg ) were studied . at four months of age , chow diet - fed mice were divided into 2 groups ( n = 7 ) and fed semi - synthetic hfs diet based on corn oil ( 20 % wt / wt total lipid content ) either with replacement of 44 % ( wt / wt ) of its fat content by epax 4510tg ( rich in epa ) or epax 1050tg ( rich in dha ). after two months on the respective diets , the addition of both types of omega - 3 pufa products to the diet resulted in a reduction of body weight , see table 1 belove . however , the dha rich product epax 1050tg exhibited stronger effect compared to epax 4510tg on weight reduction . additionally , the results of this study confirm significant effects supporting the weight - reducing effect influenced of a epax rich in dha . study 5 : effects of a fatty acid composition rich in epa versus a fatty acid composition rich in dha on reduction in dna in this study , further potential differences in effects between a dha - enriched omega - 3 product ( herein presented as a fatty acid composition comprising approximately 20 % epa and 50 % dha ( epax1005tg concentrate )) and an epa product ( rich in epa , herein presented as a fatty acid composition comprising about 45 % epa and 10 % dha ; epax4510tg ) were studied . at four months of age , chow diet - fed mice were divided into 3 groups ( n = 7 ) and fed semi - synthetic hfs diet based on flaxseed oil ( alpha - linoleic acid constitutes about 50 % of total lipids ) either with replacement of 30 % ( wt / wt ) of its fat content by epax 4510tg ( rich in epa ; hatched bars ) or epax 2050tg ( rich in dha ; black bars ), or the semi - synthetic hf diet alone ( open bars ). after one month on the respective diets , dna was analysed . addition of the omega - 3 pufa product rich in dha ( epax 2050tg ) to the diet resulted in a reduction of dna , which may indicate a reduction of the number of fat cells , see fig4 . thus , a dha - concentrate and / or a fatty acid composition rich in dha according to the invention leads to reduction of dna , which seems to indicate a reduction of the number of fat cells ( i . e . fat cells are killed ) in adipose tissue . study 6 : prevention of body weight gain and obesity in this sixth study the effect of an omega - 3 fatty acid composition comprising a combination of epa and dha ( approximately 20 % epa and 50 % dha ) on prevention of obesity and gain of weight , was studied . groups ( n = 7 ) of adult c57bl / 6j male mice were housed in a controlled environment ( 200 c , 12 - h light - dark cycle , light from 6 : 00 a . m .) with free access to water and standard chow diet enriched with sunflower oil as the main lipid constituent and containing negligible amounts of lc omega - 3 pufa . at 4 months of age (− 2 weeks ) the chow diet was replaced by a hf ( high - fat ) diet or herein a so called obesity - promoting hf diet ( 35 % wt / wt total lipid content ), please see fig5 a for diet composition . the energy density of the hf composite diet was 22 . 3 kj / g . when the mice &# 39 ; s were offered the hf ( high fat ) composite diet they started to gain body weight at a much higher rate than maintained on chow diet . two weeks later ( 0 weeks ) the animals were divided into 5 subgroups and fed ad libitum hf composite diet , either with no further modification ( full circles ), or with replacement of 15 % ( wt / wt ; i . e . 9 % dietary lipids by epa + dha ; empty circles ) or 44 % ( wt / wt ; i . e . 26 % lipids formed by epa + dha ; full triangles ) of its fat content by epax 2050tg ( rich in dha ), see table 2 below . hf composite hf composite composition content diet c - diet : - product epa / dha ) a (% lipids ) b amount epa amount dha epax 1050tg 6 / 51 15 0 . 33 2 . 80 epax 1050tg 6 / 51 44 0 . 97 8 . 26 a amounts of epa and dha in different products are expressed as g epa / g dha in 100 g of the product b percentage ( wt / wt ) of the lipid components in the diet replaced by omega - 3 pufa product c hf composite diet ( 35 % wt / wt total lipid content ) and a portion of the lipid component was replaced by epax1050 products mice on the calorie restriction ( cr ) regime ( 30 % calorie restriction when compared with ad libitum fed maice on the same diet ) were fed either the hf composite diet alone ( empty triangles ) or the diet , in which 15 % ( wt / wt ) of the lipids in the diet was formed by epax 1050tg ( i . e . about 3 out of 35 g of the lipids in each 100 g of the diet , about 9 % of lipids , were replaced by epa / dha ; full squares ). the results of this study are shown in fig5 b . weight gain was apparent after about 2 weeks of habituation on the hf diet and reached about 6 . 5 g within the next 5 weeks of the experiment . body weight gain was about 2 . 7 g lower in mice fed a hf composite diet where 15 % lipids in the diet were replaced by omega - 3 product epax 1050 tg ( rich in dha ) compared to mice fed only the hf composite diet . this states that even a low dose of omega - 3 product ( only 15 % w / w of the fat content of the diet ) slowed down the development of obesity in ad libitum fed mice . replacement of 44 % of the lipids by the epax1050 tg resulted in a net loss of body weight of about 3 g over 5 - weeks feeding period . under these conditions the omega - 3 group lost body weight during the 5 - week treatment while the control group ( regular hf diet ) gained body weight . the above indicates a dose - dependent effect of the omega - 3 product added to regular hf obesity - promoting diet , and under the condition of development of obesity even a low dose of a fatty acid composition rich in dha reduced gain in body weight already after 5 weeks of treatment . please also se a summary in fig5 c . as is also be apparently from the study , 30 % calorie restriction in animals fed hf composite diet resulted in a net loss of body weight during 5 weeks of treatment while admixing epax 1050 in the diet of the cr - animals only has a small extensive effect on weight loss , i . e . a additive effect on body weight reduction , compared to animals on 30 % cr . therefore , the interaction between cr and omega - 3 products will be investigated more in detail in a further study . please also note that replacement of dietary lipids by the omega - 3 - product seams not to affect food consumption of the animals . moreover , the results from this study show that administration of a fatty acid composition rich in dha in low doses results in significant inhibitation or prevention of weight gain . a fatty acid composition rich in dha in a higher dose shows both significant inhibition or prevention of weight gain and a weight - lowering effect under the conditions of developing obesity . thus the dose of epax 1050 tg required to counteract the increase in body weight in the context of dietary obesity is lower than that required to reduce body weight in animals maintaining relatively stable body weight on the hf semi - synthetic diet . apparently , development of obesity makes the organism more sensitive to the weight - reducing effect of the fatty acid composition comprising epa and dha . additionally , the experiment described above demonstrates significant reduction of obesity in mice fed hf composite diet containing long chain omega - 3 fatty acids . this study shows that treatment of obese , or overweight animals with a fatty acid composition containing epa and dha , wherein the amount of dha ≧ epa , also leads to prevention of weight gain . the effect of preventing body weight gain also means prevention of obesity or an overweight condition . study 7 : weight reduction under the condition of developing obesity , and additive effect of calorie restriction ( cr ) and an omega - 3 fatty acid composition in the previous study , the effect of calorie restriction and a fatty acid composition rich in dha on weight reduction under the condition of developing obesity was not fully evaluated . therefore , a complementary study on the interaction between calorie restriction and omega - 3 products , herein presented as a dha - enrich omega - 3 product comprising approximately 10 % epa and 50 % dha ( epax1050tg ), during development of obesity in mice was performed . group of c57bl / 6j male mice ( n = 7 ) were housed in a controlled environment ( 20 ° c ., 12 - h light - dark cycle , light from 6 : 00 a . m .) with free access to water and standard chow diet . at 4 months of age , the animals were randomly assigned to a obesity - promoting hf ( high - fat ) diet , please see fig4 a for diet composition . two weeks later ( week 0 ) after habituation on the diet mentioned above , the animals were divided into 4 groups : a ) hf composite diet ad libitum ; b ) hf composite diet with 10 % calorie restriction compared to ( a ); c ) fed ad libitum by hf composite diet where 15 % of the fat content of the diet was replaced by epax1050tg ; and d ) fed ad libitum hf composite diet where 15 % of the fat content of the diet was replaced by epax1050tg and the amount of food was restricted by 10 % compared to ( a ). the animals were fed the different diets during 5 weeks . the results in fig6 show that treatment under conditions of developing obesity with a fatty acid composition containing at least one of epa and dha or combinations thereof , significantly decreases the gain in body weight in relation to mice only fed obesity - promoting hf diet . in contrast to the previous study , the mild calorie restriction reduced development of obesity . herein the difference between hf - ad libit and hf + epax - ad lib is statistically significant ( paired t - test , p ≦ 0 . 03 ). moreover , the combination of the two treatments , i . e . were 10 % of the amount of food was restricted and 15 % of the fat content of the diet was replaced by epax1050tg , has an additive effect resulting in prevention of the body weight gain as compared to the control hf diet fed mice . the results in the seventh study show that a fatty acid composition rich in dha enhances the effect of calorie restriction ( cr ) on developing obesity in animals fed hf composite diet , i . e . under the conditions closely mimicing obesity in humans consuming excessive amounts of high fat containing diet . high food intake renders an animal or a human more sensitive to the effect of fatty acid composition comprising at least one of epa and dha or combinations thereof , and seems to be necessary for the additive effect concerning prevention of body weight gain of a fatty acid composition comprising at least one of epa and dha , or combinations thereof and calorie restriction to occur . this states that a fatty acid composition comprising at least one of epa and dha , or any combinations thereof , not only reduces body weight but may also prevent gain of weight and obesity . once again a best mode according to the invention may be achieved by using a product rich dha , preferably dha ≧ epa . additionally , these results also open up for a more manageable dietary regime of calorie restriction for a human since the result show an effect already at low levels of calorie restriction . concerning the dose , the results from mice may be extrapolated to humans , as far as the relative content of the fatty acid composition according to the invention , for instance an fatty acid composition containing epa and dha or any combinations thereof , in the diet is concerned . in the studies before , a semi - synthetic diet containing 20 % ( w / w ) fat was used , and an effect on weight reduction was observed when at least about 28 % of the lipid content was replaced by a fatty acid composition according to the invention ( by the addition of a fatty acid composition according to the invention ), while there was almost no effect on weight reduction when a fatty acid composition according to the invention formed 9 % of the lipid content of the diet . these diets provided 40 % of the energy from lipids . the relative content of the fatty acid composition according to the invention with respect to the total lipid content ( in the diet ) may be more important than the absolute intake , as far as the effect on weight reduction is concerned . therefore , one embodiment of the invention is to replace at least ⅓ of the total lipid in the diet by a fatty acid composition comprising at least one of dha and epa or any combinations thereof , according to the invention . please see some relevant fictive scenarios presented below . 1 . a human on a low calorie diet consume , 1000 kcal / day with 18 % calories from fat . in order to replace 28 % of 20 g of the a total lipid intake by a fatty acid composition according to the invention , the person need 5 . 6 g fatty acid composition / day . by assumed synergism between calorie restriction and the fatty acid composition according to the invention in the effect on weight reduction , also lower concentrations of the fatty acid composition in dietary lipids show effect on weight reduction . in another preferred embodiment of the invention , at least 15 % of the lipid content in the diet is replaced by the fatty acid composition according to the invention . this means about 3 g of the fatty acid composition per day , in a very low calorie diet of 1000 kcal / day with 18 % calories from fat . in a preferred embodiment of the invention , the treatment and / or prevention of obesity or overweight conditions , or for weight control and / or for prevention of body weight gain according to the invention , is carried out together with a reduced intake of calories for a human or an animal . preferably , the dietary regime of calorie reduction is combined with physical activity . in another preferred embodiment of the invention , said reduced intake of calories is reduced to at least 800 kcal ( 2520 kj per day ) or less , for a short and drastic treatment of obese patients ( adult persons ). in a more preferred embodiment , said fatty acid composition comprising at least one of epa , derivatives thereof , and dha , or any derivatives thereof , or any combinations thereof , is administered in a daily dosage from ( corresponding to ) 10 up to 40 % of the total lipid content of a daily diet for a human . moreover , to achieve a improved result , the lipid content of the diet may be lowered to at least 15 % of its energy content . the fatty acid composition according to the invention is preferably administered daily , divided in dosage , for periods up to 1 - 5 years . on the other hand , the dosage of the fatty acid composition according to the invention may also be related to the amount of omega - 3 fatty acids consumed by for instance eskymo &# 39 ; s or similar native people . therefore , in an another embodiment of the invention said fatty acid composition comprising at least one of epa and dha , or derivatives thereof , or any combinations thereof , is administered in an amount providing a daily dosage of 1 g to 15 g of said fatty acid composition . more preferred in an amount of 1 to 10 g , and most preferred an amount of between 2 and 6 g per day . the results shows that a fatty acid composition comprising at least one of epa and dha or any combinations thereof , reduce body weight and / or prevent body weight gain . the weight lowering effect of a product according to the invention that is rich in dha is stronger compared to a product containing more epa than dha . moreover , preferably a specific weight - lowering effect and prevention of body weight gain is achieved of a fatty acid composition according to the invention of marine origin . further , based on the results , calculations of doses and commercial value , the use of the fatty acid composition according to the present invention preferably may go hand - in - hand with a dietary regimen of calorie reduction . moreover , an additive effect of a fatty acid composition according to the invention combined with calorie restriction is achieved under conditions of high food intake and development of an overweight condition or obesity . it is also obvious to expect the same weight lowering effect and / or prevention of body weight gain on both humans and animals by administering the fatty acid composition according to the invention . additionally , a dha - concentrate and / or a fatty acid composition rich in dha according to the invention may reduce the number of fat cells in adipose tissue . reduction of body weight and / or prevention of body weight gain due to administration of a fatty acid composition according to the invention , preferably a fatty acid composition rich in dha , may result , at least in part , from increased oxidation of lipids ( fatty acids ) inside adipose tissue cells in a human or an animal . thus , a fatty acid composition , preferably rich in dha , induces metabolic switch in adipocytes ( fat cells ) that seem to prevent accumulation of body fat . the switch may be activated by direct interaction of a fatty acid composition according to the invention , preferably a fatty acid composition rich in dha , with adipocytes through induction of genes controlling oxidative capacity of mitochondria . transcriptional factors orchestrating mitochondrial biogenesis ( pgc1 and nrf1 ) seem to be involved . changes in gene expression seem to result in increased content of mitochondrial components which are critical for oxidation of various substrates , including lipids , in adipocytes . further , a fatty acid according to the invention may increase the ratio between the activities of fatty acid oxidation and synthesis in adipose tissue , thus activating a metabolic switch . the invention shall not be limited to the shown embodiments and examples .
a method is disclosed for treatment and prevention of obesity , an overweight condition or for controlling body weight reduction , wherein an effective amount of a fatty acid composition comprising at least one of - 5 , 8 , 11 , 14 , 17 - eicosapentaenoic acid and - 4 , 7 , 10 , 13 , 16 , 19 - docosahexaenoic acid or any combinations thereof , is administered to a human or an animal . additionally , a dietary product is disclosed , containing a fatty acid composition comprising at least one of epa and dha or any combinations thereof , for non - medical treatment of obesity , an overweight condition and / or for supporting and controlling body weight reduction . finally , a method is disclosed for supplementing a dietary product with a fatty acid composition mentioned above .