"Long before it's in the papers"
November 06, 2007

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Think food, not nutrients, researchers advise

Nov. 6, 2007
Courtesy University of Minnesota
and World Science staff

Grow­ing num­bers of re­search­ers are ar­gu­ing that the key to a healthy di­et is­n’t so much fo­cus­ing on spe­cif­ic nu­tri­ents as it is eat­ing var­ied, healthy foods in gen­er­al.

The no­tion is con­tra­ry to pop­u­lar prac­tice in food in­dus­try and gov­ern­ment, which often dis­pense health ad­vice fo­cus­ing to­tal fat, car­bo­hy­drate and pro­tein and spe­cif­ic vi­ta­mins, ac­cord­ing to Da­vid Ja­cobs, a pro­fes­sor of pub­lic health at the Un­ivers­ity of Min­ne­so­ta. Ja­cobs out­lined some of the new think­ing in an ar­ti­cle he co-authored in last mon­th’s Jour­nal of Nu­tri­tion Re­views. 

Re­cent stud­ies have found that a "Mediterranean" di­et with plen­ty of plant-based foods, some fish and lit­tle dairy and meat is linked to a va­ri­e­ty of healthy out­comes in­clud­ing low­er death rates.  (Im­age cour­te­sy U.S. Dept. of Agri­cul­ture)

“We are con­fus­ing our­selves and the pub­lic by talk­ing so much about nu­tri­ents when we should be talk­ing about foods,” said Ja­cobs. “Con­sumers get the idea that di­et and health can be un­der­stood in terms of iso­lat­ed nu­tri­ents. It’s not the best ap­proach, and it might be wrong.” 

Ja­cobs, with Lin­da Tapsell of the Un­ivers­ity of Wol­lon­gong in Aus­tral­ia, ar­gued that peo­ple should shift the fo­cus to­ward the ben­e­fits of en­tire food prod­ucts and food pat­terns in or­der to bet­ter un­der­stand nu­tri­tion. 

They fo­cus on the con­cept of food syn­er­gy – the idea that more in­forma­t­ion about the im­pact of hu­man health can be ob­tained by look­ing at whole foods than a sin­gle food com­po­nent (such as vit­a­min C, or cal­ci­um added to a con­tain­er of or­ange juice). 

Ja­cobs and Tapsell offered sev­er­al ex­am­ples in which the sin­gle nu­tri­ent ap­proach to nu­tri­tion has not proved to ben­e­fit health.

Long term ran­dom­ized clin­i­cal tri­als have failed to show ben­e­fit or have even sug­gested harm from iso­lat­ed sup­ple­ments of beta-carotene and B-vi­ta­mins, they said. A si­m­i­lar large ex­pe­ri­ment in to­tal fat re­duc­tion al­so did not show ben­e­fit. In con­trast, they added, ob­serva­t­ions have shown im­proved long-term health for foods and food pat­terns that in­cor­po­rate these same nu­tri­ents nat­u­rally oc­cur­ring in food. 

An un­der­standing of the in­ter­ac­tions be­tween food com­po­nents in both sin­gle foods and whole di­ets opens up new ar­eas of think­ing that may have great­er ap­plica­t­ion to con­tem­po­rary popula­t­ion health is­sues, par­tic­u­larly those re­lat­ed to chron­ic lifestyle dis­ease, Ja­cobs said. 

This “begs for much more whole food-based re­search, and en­cour­ages us in both re­search and di­etary ad­vice to ‘think food first,’”  Tap­sell said. 

* * *

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Growing numbers of researchers are arguing that the key to a healthy diet isn’t so much focusing on specific nutrients as it is eating varied, healthy foods in general. This notion is contrary to popular practice in food industry and government, where marketers and regulators tend to focus on total fat, carbohydrate and protein and on specific vitamins, said David Jacobs, a professor of public health at the University of Minnesota. Jacobs outlined some of the new thinking in an article he co-authored in last month’s Journal of Nutrition Reviews. “We are confusing ourselves and the public by talking so much about nutrients when we should be talking about foods,” said Jacobs. “Consumers get the idea that diet and health can be understood in terms of isolated nutrients. It’s not the best approach, and it might be wrong.” Jacobs, with Linda Tapsell of the University of Wollongong in Australia, argued that people should shift the focus toward the benefits of entire food products and food patterns in order to better understand nutrition in regard to a healthy human body. They focus on the concept of food synergy – the idea that more information about the impact of human health can be obtained by looking at whole foods than a single food component (such as vitamin C, or calcium added to a container of orange juice). Jacobs and Tapsell provide several examples in which the single nutrient approach to nutrition has not proved to benefit health: Long term randomized clinical trials, considered the gold standard for making judgments about nutritional treatment and health, have failed to show benefit or have suggested harm for cardiovascular events for isolated supplements of beta-carotene and B-vitamins. A similar large experiment in total fat reduction also did not show benefit. In contrast, myriad observations have been made of improved long-term health for foods and food patterns that incorporate these same nutrients naturally occurring in food. An understanding of the interactions between food components in both single foods and whole diets opens up new areas of thinking that appear to have greater application to contemporary population health issues, particularly those related to chronic lifestyle disease, Jacobs said. “It is this new understanding that reminds us emphatically of the central position of food in the nutrition-health interface, which begs for much more whole food-based research, and encourages us in both research and dietary advice to, ‘think food first’,” Tapsell said.