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Summarising lecture and prospects for future research and development
Food Research International 35 (2002) 323–325 www.elsevier.com/locate/foodres
Summarising lecture and prospects for future research and development Helmut F. Erbersdobler* Institute for Human Nutrition and Food Science, Kiel University, Du¨sternbrooker Weg 17-19, D-24105 Kiel, Germany Received 17 January 2001; accepted 5 May 2001
1. Introduction Today, many functional food applications are in use and much more developments can be expected in the future. However, the main functional food ingredients still more or less consist of nutrients like special vitamins, n-3 fatty acids, plant sterols or dietary fibre components. Of the most promising other groups the key compounds are still not known or not definitely identified. Moreover, there are many future compounds, like resveratrols, conjugated linoleic acids etc., for which we do not have enough data, yet. Some other spectacular offers and options are not scientifically sound. They are harmful for all good intentions with functional foods and the seriousness of the whole idea.
2. The challenge For most of the promising future compounds, but in details also for established functional foods, sufficient human studies and defined characterisations are lacking. The most promising group so far are the probiotic and prebiotic acting food items. As was demonstrated in the first part of the symposium, there are a lot of positive effects of probiotics and prebiotics. However, many questions remain to be solved as is summarised in Table 1. The so called secondary bioactive plant constituents with a reservoir of more than 5000 ingredients are one
* Corresponding author. Tel.: +49-431-597-3680; fax: +49-431597-3680. E-mail address: [email protected] (H.F. Erbersdobler).
of the promising group of antioxidative and immune stimulating compounds. They are partially grouped between functional foods and nutraceuticals. New biomarker techniques and the establishing of data bases for the different functional food ingredients together with results from nutritional epidemiology will enhance the knowledge about these food constituents. On the other hand, it has to be proved how much side effects have to be expected and whether some effects would not be achieved better by using drugs. Generally the differentiation between nutritional and therapeutical applications will partially be lost but should be kept in mind, at least with regard to the different legislation in both fields. In Table 2 some critical points of this differentiation are listed. Another problem is the practical use of functional foods especially of such ingredients which must be provided regularly and in the long term. Table 3 shows the relevance of duration of several functional food (FF) effects. This raises the question, how we can organise a longterm intake of functional foods? This would be easy if the compound must not be supplied very regularly, e.g. because there is some storage in several compartments of the body like in the cases of iodine, n-3 fatty acids, tocopherols, carotenoids and others. A weekly consumption of higher amounts of these compounds would be sufficient. Another policy, reaching also all groups of the population at risk would be to enrich daily used foods like common salt, flour or bread etc. This has been successfully established in many cases like the enrichment of common salt with iodine in Switzerland, Austria and recently Germany. Further programs (e.g. folate in flour, iron in bread) are under discussion or just in use. A disadvantage of such strategies is the fact that groups of the population which do not need a supplementation or are even sensitive to the ingredient are
0963-9969/02/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved. PII: S0963-9969(01)00203-4
324
H.F. Erbersdobler / Food Research International 35 (2002) 323–325
forced to eat it. For example this is discussed in the case of the oxidative iron for adult and older men. A subgroup of supplementation programs, overcoming some of the above-mentioned problems, would be the permanent enrichment of several canteen meals or some fast food items with critical nutrients or functional food ingredients. In this way the consumer would have the free choice to select the ‘‘healthy food’’ or not. On the other hand, this procedure is limited by the fact that the uptake depends on the consumer’s taste and preferences. Therefore, a statistically sophisticated program changing the distribution of the compounds over all types of meals offered would be necessary. In some cases it would be possible to offer the consumer a FF item which he can use regularly according to his eating habits. Examples would be the FF-juice in the morning or the fat spread enriched with an FF-ingredient. The ultimately efficient strategy would be a complete computerised program of a long-term FF intake. However this procedure would only work in groups of high-risk patients or interested and collaborating persons. Taking into account all these facts we can establish ‘‘ten rules’’ for functional food intake which are valid for all, scientists, authorities, producers, and consumers (Table 4).
Table 1 Concerns connected with probiotics Which probiotic in what concentration, how often? Can different products be mixed? Is there a synergistic effect? How much butyrate is produced in vivo from the different prebiotic acting oligo- and polysaccharides? Would it be useful to concentrate on the health of the gut or should we expand to general health problems (like influenza etc.)? A concerted action of the relevant companies is necessary with general proposals for consumption (like the common platform in computer systems some years ago)
Table 2 A comparison of a functional food (FF) ingredient with the relevant drug Effects
Drug
Therapeutical effects FF-effects Side effects Adverse effects Tested Legislation A doctor included (prescription)
1a 1 or lower 1 Known Best Clear Yes (mostly)
FF ingredient 0.1 or lower 1 <1>? All known? Incomplete Uncertain No (no)
Table 3 Some examples for the scope in which certain functional food effects are expected to become relevant Effects (compounds)
Application (+) and onset of effects (++) Short range (weeks) Medium range (months to years) Long range (20–30 years)
Iodine, struma prevention
+(++)
++
++
Hypotensive (peptides) CVDa-prevention
++ –
+ –
+ ++
Cholesterol lowering (e.g. phytosterols) CVD-prevention
++ –
+ –
+ ++
Probiotics Stimulation of the immune system Possibly cancer prevention
++ – –
+ ++(?) –
+ ++(?)
(o-3-fatty acids) anticoagulant Antiarrhythmic Lowering of plasma-triglycerides CVD-prevention
++ ++ ++ ++
+ + + ++
+ + + ++
Homocystein lowering (folic acid) CVD-prevention
+ –
++ –
+ ++
Osteoporosis (calcium, phytoestrogens)
+
+
++
Cancer prevention, antioxidants (flavenoids, Tocopherols etc.)
+
+
++
CVD-prevention, antioxidants
+
+
++(?)
a
CVD, cardio vascular diseases.
H.F. Erbersdobler / Food Research International 35 (2002) 323–325 Table 4 The ‘‘ten rules’’ for functional foods (FF) 1. Recommend and use only scientifically tested and proven constituents and foods 2. Watch side effects; compare to the effects of related drugs 3. Look at the right matrix 4. Improve legislation 5. Take the right dosage (not too less–not too much) 6. Look at good quality of your nutrition in general 7. Eat FF moderate but enough and regularly 8. Do not change too much between different items 9. Remember the long term compliance 10. Do not forget the doctor
325
3. Future prospects Molecular medicine and molecular genetics will provide the prerequisite and informations for the specific use and also for new applications of functional foods. This will include food from genetic engineering with increasing tendency. This and other techniques of food processing will lead to new kinds of food and food mixtures. The advanced knowledge and the new possibilities will be challenging nutritional education and information. This will demand new strategies including modern instruments of marketing and consumer psychology. They will have to be applied, also by considering ethical aspects, in a concerted action by scientists, political authorities, and food industry.
Summarising lecture and prospects for future research and development Helmut F. Erbersdobler* Institute for Human Nutrition and Food Science, Kiel University, Du¨sternbrooker Weg 17-19, D-24105 Kiel, Germany Received 17 January 2001; accepted 5 May 2001
1. Introduction Today, many functional food applications are in use and much more developments can be expected in the future. However, the main functional food ingredients still more or less consist of nutrients like special vitamins, n-3 fatty acids, plant sterols or dietary fibre components. Of the most promising other groups the key compounds are still not known or not definitely identified. Moreover, there are many future compounds, like resveratrols, conjugated linoleic acids etc., for which we do not have enough data, yet. Some other spectacular offers and options are not scientifically sound. They are harmful for all good intentions with functional foods and the seriousness of the whole idea.
2. The challenge For most of the promising future compounds, but in details also for established functional foods, sufficient human studies and defined characterisations are lacking. The most promising group so far are the probiotic and prebiotic acting food items. As was demonstrated in the first part of the symposium, there are a lot of positive effects of probiotics and prebiotics. However, many questions remain to be solved as is summarised in Table 1. The so called secondary bioactive plant constituents with a reservoir of more than 5000 ingredients are one
* Corresponding author. Tel.: +49-431-597-3680; fax: +49-431597-3680. E-mail address: [email protected] (H.F. Erbersdobler).
of the promising group of antioxidative and immune stimulating compounds. They are partially grouped between functional foods and nutraceuticals. New biomarker techniques and the establishing of data bases for the different functional food ingredients together with results from nutritional epidemiology will enhance the knowledge about these food constituents. On the other hand, it has to be proved how much side effects have to be expected and whether some effects would not be achieved better by using drugs. Generally the differentiation between nutritional and therapeutical applications will partially be lost but should be kept in mind, at least with regard to the different legislation in both fields. In Table 2 some critical points of this differentiation are listed. Another problem is the practical use of functional foods especially of such ingredients which must be provided regularly and in the long term. Table 3 shows the relevance of duration of several functional food (FF) effects. This raises the question, how we can organise a longterm intake of functional foods? This would be easy if the compound must not be supplied very regularly, e.g. because there is some storage in several compartments of the body like in the cases of iodine, n-3 fatty acids, tocopherols, carotenoids and others. A weekly consumption of higher amounts of these compounds would be sufficient. Another policy, reaching also all groups of the population at risk would be to enrich daily used foods like common salt, flour or bread etc. This has been successfully established in many cases like the enrichment of common salt with iodine in Switzerland, Austria and recently Germany. Further programs (e.g. folate in flour, iron in bread) are under discussion or just in use. A disadvantage of such strategies is the fact that groups of the population which do not need a supplementation or are even sensitive to the ingredient are
0963-9969/02/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved. PII: S0963-9969(01)00203-4
324
H.F. Erbersdobler / Food Research International 35 (2002) 323–325
forced to eat it. For example this is discussed in the case of the oxidative iron for adult and older men. A subgroup of supplementation programs, overcoming some of the above-mentioned problems, would be the permanent enrichment of several canteen meals or some fast food items with critical nutrients or functional food ingredients. In this way the consumer would have the free choice to select the ‘‘healthy food’’ or not. On the other hand, this procedure is limited by the fact that the uptake depends on the consumer’s taste and preferences. Therefore, a statistically sophisticated program changing the distribution of the compounds over all types of meals offered would be necessary. In some cases it would be possible to offer the consumer a FF item which he can use regularly according to his eating habits. Examples would be the FF-juice in the morning or the fat spread enriched with an FF-ingredient. The ultimately efficient strategy would be a complete computerised program of a long-term FF intake. However this procedure would only work in groups of high-risk patients or interested and collaborating persons. Taking into account all these facts we can establish ‘‘ten rules’’ for functional food intake which are valid for all, scientists, authorities, producers, and consumers (Table 4).
Table 1 Concerns connected with probiotics Which probiotic in what concentration, how often? Can different products be mixed? Is there a synergistic effect? How much butyrate is produced in vivo from the different prebiotic acting oligo- and polysaccharides? Would it be useful to concentrate on the health of the gut or should we expand to general health problems (like influenza etc.)? A concerted action of the relevant companies is necessary with general proposals for consumption (like the common platform in computer systems some years ago)
Table 2 A comparison of a functional food (FF) ingredient with the relevant drug Effects
Drug
Therapeutical effects FF-effects Side effects Adverse effects Tested Legislation A doctor included (prescription)
1a 1 or lower 1 Known Best Clear Yes (mostly)
FF ingredient 0.1 or lower 1 <1>? All known? Incomplete Uncertain No (no)
Table 3 Some examples for the scope in which certain functional food effects are expected to become relevant Effects (compounds)
Application (+) and onset of effects (++) Short range (weeks) Medium range (months to years) Long range (20–30 years)
Iodine, struma prevention
+(++)
++
++
Hypotensive (peptides) CVDa-prevention
++ –
+ –
+ ++
Cholesterol lowering (e.g. phytosterols) CVD-prevention
++ –
+ –
+ ++
Probiotics Stimulation of the immune system Possibly cancer prevention
++ – –
+ ++(?) –
+ ++(?)
(o-3-fatty acids) anticoagulant Antiarrhythmic Lowering of plasma-triglycerides CVD-prevention
++ ++ ++ ++
+ + + ++
+ + + ++
Homocystein lowering (folic acid) CVD-prevention
+ –
++ –
+ ++
Osteoporosis (calcium, phytoestrogens)
+
+
++
Cancer prevention, antioxidants (flavenoids, Tocopherols etc.)
+
+
++
CVD-prevention, antioxidants
+
+
++(?)
a
CVD, cardio vascular diseases.
H.F. Erbersdobler / Food Research International 35 (2002) 323–325 Table 4 The ‘‘ten rules’’ for functional foods (FF) 1. Recommend and use only scientifically tested and proven constituents and foods 2. Watch side effects; compare to the effects of related drugs 3. Look at the right matrix 4. Improve legislation 5. Take the right dosage (not too less–not too much) 6. Look at good quality of your nutrition in general 7. Eat FF moderate but enough and regularly 8. Do not change too much between different items 9. Remember the long term compliance 10. Do not forget the doctor
325
3. Future prospects Molecular medicine and molecular genetics will provide the prerequisite and informations for the specific use and also for new applications of functional foods. This will include food from genetic engineering with increasing tendency. This and other techniques of food processing will lead to new kinds of food and food mixtures. The advanced knowledge and the new possibilities will be challenging nutritional education and information. This will demand new strategies including modern instruments of marketing and consumer psychology. They will have to be applied, also by considering ethical aspects, in a concerted action by scientists, political authorities, and food industry.