Study Suggests New Approach to Promoting a Heart-Healthy Diet

A new meta-analy­sis of dozens of sci­en­tific stud­ies has con­cluded that eat­ing foods asso­ci­ated with the tra­di­tional Mediterranean diet were linked with a lower risk of car­dio­vas­cu­lar dis­ease and coro­nary heart dis­ease.

The study, which was con­ducted by four researchers from the University of Naples Federico II and pub­lished in Cardiovascular Research, looked at the cor­re­la­tion between indi­vid­ual food groups and heart dis­ease.

The researchers hope their meta-analy­sis pro­vides a new con­text for the pub­lic to view what they eat and how they make their dietary choices.

“Most dietary rec­om­men­da­tions look specif­i­cally at nutri­ents and not at foods. The evi­dence on which they are based is evi­dence related to nutri­ents,” Gabriele Riccardi, the study’s lead author, told Olive Oil Times.

“Since peo­ple are eat­ing foods and not nutri­ents, you have to trans­late this infor­ma­tion into foods,” he added. ​“We wanted to look right at the foods and see what is the evi­dence in all the avail­able lit­er­a­ture world­wide on these large data­bases to look at the rela­tion­ship between spe­cific food con­sump­tion and car­dio­vas­cu­lar dis­ease.”

What Riccardi and the rest of his team found was hardly sur­pris­ing. However, it gave them a more nuanced approach to rec­om­mend­ing how peo­ple may change their eat­ing habits to fol­low a more heart-healthy diet.

“The evi­dence is highly con­cor­dant in show­ing that, for the healthy adult pop­u­la­tion, low con­sump­tion of salt and foods of ani­mal ori­gin, and increased intake of plant-based foods – whole grains, fruits, veg­eta­bles, legumes and nuts – are linked with reduced ath­er­o­scle­ro­sis risk,” the researchers wrote in the study. ​“The same applies for the replace­ment of but­ter and other ani­mal and trop­i­cal fats with olive oil and other unsat­u­rated-fat-rich oil.”

Indeed, the researchers found that processed red meat and unprocessed red meat were highly cor­re­lated with increased inci­dence of and mor­tal­ity from coro­nary heart dis­ease and car­dio­vas­cu­lar dis­ease.

Two out of three of the stud­ies looked at by the researchers pointed to a daily serv­ing of 50 grams of processed red meat being asso­ci­ated with a 27 per­cent to 44 per­cent increase in coro­nary heart dis­ease inci­dence.

Three sep­a­rate stud­ies showed that daily con­sump­tion of 100 grams of unprocessed red meat was also asso­ci­ated with excess car­dio­vas­cu­lar dis­ease mor­tal­ity.

The researchers also found, rather unsur­pris­ingly, that the con­sump­tion of nuts, fruits, veg­eta­bles and whole-grain cere­als were all highly cor­re­lated with lower risks of coro­nary heart dis­ease and car­dio­vas­cu­lar dis­ease occur­rence.

Five out of six stud­ies that the researchers looked at showed an inverse rela­tion­ship between fruit and veg­etable con­sump­tion and coro­nary heart dis­ease and car­dio­vas­cu­lar dis­ease. Green leafy veg­eta­bles showed the high­est lev­els of reduc­ing risk for the two dis­eases.

The same was largely true of olive oil, which was highly cor­re­lated to a lower risk of car­dio­vas­cu­lar dis­ease.

The researchers found that in a dose-response eval­u­a­tion, a five-gram increase of olive oil con­sump­tion was asso­ci­ated with a seven-per­cent decrease in coro­nary heart dis­ease inci­dence, a four-per­cent decrease in car­dio­vas­cu­lar dis­ease inci­dence and an eight-per­cent decrease in car­dio­vas­cu­lar dis­ease mor­tal­ity.

The con­sump­tion of veg­etable oils high in linoleic acids, such as saf­flower, sun­flower, corn and soy­bean oils, was also highly cor­re­lated with reduced car­dio­vas­cu­lar dis­ease inci­dence and mor­tal­ity.

The results of their study led the researchers to draft a new food con­sump­tion guide. It looks very sim­i­lar to the United States Food and Drug Administration’s food guide pyra­mid, but with a few major dif­fer­ences.

“If we want to reduce the risk of car­dio­vas­cu­lar dis­ease world­wide, it is much more appro­pri­ate, fea­si­ble and cost-effec­tive if we ask peo­ple to con­cen­trate on foods items to pro­mote rather than food items to reduce,” Riccardi said.

“It’s much more effec­tive in reduc­ing car­dio­vas­cu­lar dis­ease to tell peo­ple to increase your con­sump­tion of fruit, veg­eta­bles, whole grains, legumes and uti­lize olive oil for sal­ads,” he added.

For Riccardi, the decades-old con­ver­sa­tion about avoid­ing cer­tain foods and macronu­tri­ents, such as fat, has not worked. Neither has the more recent one about shun­ning some fats in favor of oth­ers, a con­cept too abstract to apply on a daily basis.

“It is non­sense to say to peo­ple that you have to pre­fer unsat­u­rated fat to sat­u­rated fat because most peo­ple don’t know what sat­u­rated fat or unsat­u­rated fats are,” he said.

“Instead, it is much eas­ier and direct to tell the con­sumers, in rela­tion to cook­ing fat, olive oils should be the pre­ferred source of monoun­sat­u­rated fats and should replace but­ter and other ani­mal fats or trop­i­cal oils when­ever pos­si­ble,” Riccardi added.

He hopes that gov­ern­ments and the food indus­try pay atten­tion to this study, but acknowl­edged that get­ting peo­ple to change how they eat has been widely unsuc­cess­ful, even in the face of the indi­vid­ual find­ings of the dozens of stud­ies his team ana­lyzed.

“We know that diet is able to reduce car­dio­vas­cu­lar dis­ease events by as much as 50 per­cent,” he said. ​“That’s a lot. The prob­lem is, what can we do to make peo­ple change.”

Part of the issue is the piece­meal nature of sci­en­tific stud­ies, many of which have a very nar­row focus and are dif­fi­cult for mem­bers of the pub­lic to put into a broader con­text. Part of Riccardi’s idea was to pro­vide some of that con­text in this type of study.

“We know how peo­ple should change, but we don’t know how to con­vince peo­ple to make the right choices,” Riccardi said. ​“I hope that bas­ing our study on solid evi­dence and giv­ing empha­sis to pos­i­tive change rather than neg­a­tive change can make a dif­fer­ence in rela­tion to what has been done in the past.”

He added that his research team plans to do the same thing with type 2 dia­betes, iden­ti­fy­ing the spe­cific rela­tion­ships of food and food groups with the chronic dis­ease. The goal of this study will also be to help peo­ple iden­tify which foods to eat more of and which foods to cut back on.

“The healthy diet is not a pun­ish­ment for peo­ple,” Riccardi said. ​“Instead, it is a resource of gas­tro­nomic appeal and plea­sure at the table.”

“We know that it is pos­si­ble for peo­ple to eat well, to eat with plea­sure and that’s one of the mes­sages of the Mediterranean diet,” he con­cluded. ​“You can have a very nice diet, very appeal­ing with foods that you love and at the same time to have this type of diet can have a ben­e­fi­cial impact on your health, par­tic­u­larly on car­dio­vas­cu­lar dis­ease risk.”

• Cardiovascular Research
• Washington Post