Traditionally investigations of a foodstuff's implications for human health focus on the content of individual nutrients such as proteins, fats, carbohydrates, etc. However, newer research shows that the health effects of a food product cannot be determined on the basis on the individual nutrients it contains. The food must be evaluated as a whole - together with other foods eaten at the same time. The findings of the expert panel have been published in the highly respected scientific journal the American Journal of Clinical Nutrition.
We consume foods and meals - not nutrients
Postdoc Tanja Kongerslev Thorning, PhD, from the Department of Nutrition, Exercise and Sports at the University of Copenhagen, is first author of the report. Tanja explains that scientists have long wondered why the actual effects of a food are at variance with the effects expected on the basis of its nutrition content. They have therefore started to look at things in a wider context:
"Researchers have become more skilful over the years, and we have acquired more methods for exploring what specific nutrients mean for digestion and health," Tanja continues "But when we eat, we do not consume individual nutrients. We eat the whole food. Either alone or together with other foods in a meal. It therefore seems obvious that we should assess food products in context."
Ultimately this means that the composition of a food can alter the properties of the nutrients contained within it, in ways that cannot be predicted on the basis of an analysis of the individual nutrients. For example, dairy products such as cheese have a lesser effect on blood cholesterol than would be predicted on the basis of their content of saturated fat. There are interactions between the nutrients in a food that are significant for its overall effect on health.
Tanja Kongerslev Thorning explains further "Another example is almonds, which contain a lot of fat, but which release less fat than expected during digestion. Even when chewed really well. The effects on health of a food item are probably a combination of the relationship between its nutrients, and also of the methods used in its preparation or production. This means that some foods may be better for us, or less healthy, than is currently believed."
Some of the precepts of current nutrition science need to be reconsidered
The expert panel behind these conclusions consists of 18 experts in epidemiology, food, nutrition and medical science. They were brought together for a workshop organized by the University of Copenhagen in collaboration with the University of Reading in September 2016. Discussions focussed on dairy products, and on how the complex mixture of nutrients and bioactive substances, such as minerals and vitamins, can affect digestion and ultimately change the overall nutritional and health properties of a particular food.
The panel concluded, among other things, that yoghurt and cheese have a different and more beneficial effect on bone health, body weight, the risk of developing cardiovascular diseases, than would be expected on the basis of their saturated fat and calcium content.
Head of Department of Nutrition, Exercise and Sports at the University of Copenhagen, professor Arne Astrup, who chaired the workshop, explains that the example of cheese is good to illustrate that a food's health effects cannot be judged by single nutrients e.g. sodium and saturated fat:
"In contrast to current recommendations that essentially ban full-fat cheese, current research clearly demonstrate important health benefits of cheese for prevention of type 2 diabetes, cardiovascular disease and cancers. All the positive effects are due to a complex interaction between beneficial bacteria, minerals and bio-active cheese ingredients."
Professor of Food Chain Nutrition Ian Givens at the University of Reading, co-chair of the meeting, concludes:
"More studies are needed, but ultimately it seems that some areas of nutrition science need to be rethought. We cannot focus on a nutrient without looking at how it is consumed and what else is eaten at the same time."
The findings are published in the article Whole dairy matrix or single nutrients in assessment of health effects: current evidence and knowledge gaps in the American Journal of Clinical Nutrition.
Postdoc Tanja Kongerslev Thorning, PhD
Department of Nutrition, Exercise and Sports, University of Copenhagen
Telelephone: +45 3533 3638
Professor Ian Givens
University of Reading
Telelephone: +44 (0) 118 378 8491
Head of Department,
Professor Arne Astrup, MD, DMSc
Department of Nutrition, Exercise and Sports,
University of Copenhagen
Telelephone: +45 2143 3302
Kristian Levring Madsen
Department of Nutrition, Exercise and Sports
University of Copenhagen
Telelephone: +45 4048 1684
American Journal of Clinical Nutrition
Kwa kawaida uchunguzi wa athari za chakula kwa afya ya binadamu unazingatia maudhui ya virutubisho vya mtu binafsi kama vile protini, mafuta, wanga, nk. Hata hivyo, utafiti mpya unaonyesha kwamba athari za afya za bidhaa za chakula haziwezi kuamuliwa kwa msingi wa virutubisho vyake. Chakula hicho lazima kichunguzwe kwa ujumla - pamoja na vyakula vingine vinavyokula wakati huohuo. Matokeo ya uchunguzi huo yamechapishwa katika jarida la kisayansi linalojulikana sana, American Journal of Clinical Nutrition. "Tunachukua chakula na chakula - si virutubisho "" Postdoc Tanja Kongerslev Thorning, PhD, kutoka Idara ya Lishe, Mazoezi na Michezo katika Chuo Kikuu cha Copenhagen, ni mwandishi wa kwanza wa ripoti." "Tanja anaeleza kwamba wanasayansi wamekuwa wakijiuliza kwa muda mrefu kwa nini athari halisi za chakula hutofautiana na matokeo yanayotarajiwa kwa msingi wa ""maumbile yake.""" "Kwa hivyo wameanza kuangalia mambo katika muktadha mkubwa: ""Watafiti wamekuwa na ustadi zaidi kwa miaka, na tumepata mbinu zaidi za kuchunguza nini virutubisho maalum vina maana kwa digestive na afya,"" Tanja anaendelea. ""Lakini wakati tunakula, hatutumii virutubisho vya mtu binafsi." Tunakula chakula chote. Kwa vyovyote vile, peke yake au pamoja na vyakula vingine katika mlo. Kwa hiyo inaonekana wazi kwamba tunapaswa kutathmini bidhaa za chakula katika muktadha. " Hii inamaanisha kwamba muundo wa chakula unaweza kubadilisha sifa za virutubisho vilivyo ndani yake kwa njia ambazo haziwezi kutabiriwa kwa msingi wa uchambuzi wa virutubisho vya mtu binafsi. Kwa mfano, bidhaa za maziwa kama vile jibini zina athari ndogo juu ya cholesterol ya damu kuliko ingekuwa kutabiriwa kwa msingi wa maudhui yao ya mafuta yaliyojaa. Kuna mwingiliano kati ya virutubisho katika chakula ambacho ni muhimu kwa athari yake ya jumla kwa afya. "Tanja Kongerslev-Thorning anaelezea zaidi: ""Mfano mwingine ni almond, ambayo ina mafuta mengi, lakini ambayo hutoa mafuta kidogo kuliko inatarajiwa wakati wa kumeng'enya." Hata wakati chewed kweli vizuri. Matokeo ya afya ya chakula ni uwezekano wa mchanganyiko wa uhusiano kati ya virutubisho vyake, na pia ya mbinu kutumika katika maandalizi yake au uzalishaji. Hii inamaanisha kwamba baadhi ya vyakula vinaweza kuwa bora kwetu, au visivyo na afya, kuliko inavyoaminika kwa sasa". "Hatua hii ya kwanza ya utafiti wa afya ya binadamu imefanywa na ""bodi ya wataalamu"" iliyoundwa na wataalamu 18 wa sayansi ya magonjwa, chakula, lishe na sayansi ya matibabu." Mkutano huo ulifanyika katika chuo kikuu cha Copenhagen, na kushirikiana na Chuo Kikuu cha Reading. Mjadala ulizingatia bidhaa za maziwa na jinsi mchanganyiko tata wa virutubisho na vitu vya bioactive, kama vile madini na vitamini, vinavyoweza kuathiri digestive na hatimaye kubadilisha mali ya jumla ya lishe na afya ya chakula fulani. "Kulingana na ripoti hiyo, ""yoghurt na jibini zina athari tofauti na nzuri zaidi kwa afya ya mifupa, uzito wa mwili, hatari ya kuendeleza magonjwa ya moyo na mishipa ya damu kuliko inatarajiwa kwa msingi wa mafuta yao ya saturated na kalsiamu.""" Mkuu wa Idara ya Lishe, Mazoezi na Michezo katika Chuo Kikuu cha Copenhagen, Profesa Arne Astrup, ambaye alisimamia semina hiyo, anaelezea kuwa mfano wa jibini ni mzuri kuonyesha kwamba athari za afya za chakula haziwezi kuhukumiwa na virutubisho vya pekee. "Kulingana na mapendekezo ya sasa ambayo kimsingi yanakataza jibini kamili, utafiti wa sasa unaonyesha wazi faida muhimu za afya za jibini kwa kuzuia ugonjwa wa kisukari wa aina ya 2, ugonjwa wa moyo na mishipa ya damu na saratani. """ Athari zote nzuri hutokana na mwingiliano tata kati ya bakteria zenye manufaa, madini na viungo vya jibini vyenye utendaji wa kibiolojia". "Profesa wa Chakula cha Mlolongo Ian Givens katika Chuo Kikuu cha Reading, mwenyekiti mwenza wa mkutano huo, anahitimisha: ""Utafiti zaidi unahitajika, lakini mwishowe inaonekana kuwa maeneo fulani ya sayansi ya lishe yanahitaji kufikiria tena." "Hatuwezi kuzingatia virutubisho bila kuangalia jinsi vinatumiwa na nini kingine kinachotumiwa wakati huohuo.""" Matokeo ya utafiti huo yamechapishwa katika makala ya The Whole Dairy Matrix or Single Nutrients in Assessment of Health Effects: Current Evidence and Knowledge Gapes katika American Journal of Clinical Nutrition. Mwalimu wa Utoaji wa Chakula, Mazoezi na Michezo, Chuo Kikuu cha Copenhagen, Tanja Kongerslev-Thorning, PhD, Idara ya Lishe, Mazoezi na Michezo, Chuo Kikuu cha Copenhagen, Kalifornia, Tel: +441-335-336-338-868-113-848 (Msomi wa Utoaji wa Chakula, Mazoezi na Michezo, Chuo Kikuu cha Copenhagen, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, Kalifornia, K