Small Dietary Changes Can Reduce Risk of Death

A mere 20 percent improvement in the quality of your diet may decrease the risk of death by 8 to 17 percent.

Aug. 2, 2017
By Mary West

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Harvard researchers have dis­cov­ered that even mod­est dietary improve­ments can make a dif­fer­ence in health and pro­mote longevity when sus­tained over time. This is encour­ag­ing news for those who find the idea of a com­plete diet over­haul intim­i­dat­ing.

Our find­ings under­score the ben­e­fits of healthy eat­ing pat­terns includ­ing the Mediterranean diet.- Mercedes Sotos-Prieto

The new study is the first to show that boost­ing diet qual­ity over at least 12 years is linked to sig­nif­i­cantly lower total mor­tal­ity, as well as lower car­dio­vas­cu­lar mor­tal­ity. It defines qual­ity in the diet as eat­ing more fruits, veg­eta­bles, nuts, whole grains and fish while reduc­ing intake of sug­ary bev­er­ages, red meat and processed meat.

Overall, our find­ings under­score the ben­e­fits of healthy eat­ing pat­terns includ­ing the Mediterranean diet and the DASH diet. Our study indi­cates that even mod­est improve­ments in diet qual­ity could mean­ing­fully influ­ence mor­tal­ity risk and con­versely, a wors­en­ing diet qual­ity may increase the risk,” said lead author Mercedes Sotos-Prieto, who worked on the study while a post­doc­toral fel­low in the Harvard Chan School Department of Nutrition and who is cur­rently an assis­tant pro­fes­sor of nutri­tion at Ohio University.

Sotos-Prieto and her col­leagues eval­u­ated data from 74,000 adults to ascer­tain the effect of diet on death risk. The data, which cov­ered a 12-year period from 1986 to 1998, came from two stud­ies: the Nurses’ Health Study and the Health Professionals’ Follow-up Study. Participants were required to pro­vide infor­ma­tion about their diet, health and lifestyle at reg­u­lar inter­vals. The researchers fol­lowed them for 12 sub­se­quent years from 1998 to 2010 to doc­u­ment fatal­i­ties.

Three scor­ing meth­ods were used to assess diet qual­ity: the Alternate Mediterranean Diet Score, the 2010 Alternate Healthy Eating Index, and the Dietary Approaches to Stop Hypertension (DASH) diet score. Each method assigns higher scores to nutri­tious food and lower scores to less healthy foods.


Analysis of the find­ings showed improved diet qual­ity over 12 years was con­nected with a lower death risk in the sub­se­quent 12 years, regard­less of what scor­ing method was used. Foods that con­tributed the most to diet qual­ity included fruits, veg­eta­bles, whole grains, fish and n‑3 fatty acids.

Most remark­ably, a 20 per­cent boost in diet qual­ity scores was linked to an 8- to 17 per­cent decrease in the risk of death. Conversely, a reduc­tion in diet qual­ity was tied to a 6- to a 12 per­cent rise in the death risk.

Participants who main­tained a higher food qual­ity score on any of the three healthy diet mea­sure­ment meth­ods over 12 years had a 9- to 14 per­cent reduc­tion in death inci­dence from any cause. In addi­tion, those who started out the study with rel­a­tively unhealthy diets but improved their eat­ing habits the most also had a sig­nif­i­cantly lower risk of death in sub­se­quent years.

The 20 per­cent improve­ment is a mod­est amount that can be attained in a vari­ety of ways. In an inter­view with Olive Oil Times, Sotos-Prieto pro­vided exam­ples of how one sim­ple daily swap from less healthy fare to more healthy fare can boost the nutri­tion of a diet enough to result in an increase in longevity. Any of the fol­low­ing exchanges can con­sti­tute a 20 per­cent increase in qual­ity of food intake:

  • Increasing nuts and legumes up to one serv­ing per day and not con­sum­ing sug­ary bev­er­ages and fruit juice dur­ing the day (One serv­ing is 1 oz of nuts or 1 table­spoon of peanut but­ter)
  • Swapping sugar and sweet­ened bev­er­ages daily for four serv­ings of fresh fruit per day (One serv­ing is 1 medium piece of fruit or 1/2 cup of berries)
  • Increasing veg­etable con­sump­tion to five serv­ings per day and decreas­ing red and processed meat con­sump­tion to 1.5 serv­ings per day to lit­tle con­sump­tion (One serv­ing of veg­gies is 1/2 cup of veg­eta­bles or 1 cup of green leafy veg­eta­bles and one serv­ing is 4 oz of unprocessed meat or 1 1/2 oz of processed meat)

Our results high­light the long-term health ben­e­fits of improv­ing diet qual­ity with an empha­sis on over­all dietary pat­terns rather than on indi­vid­ual foods or nutri­ents. A healthy eat­ing pat­tern can be adopted accord­ing to indi­vid­u­als’ food and cul­tural pref­er­ences and health con­di­tions. There is no one-size-fits-all diet,” said Frank Hu, pro­fes­sor, and chair of the Harvard Chan School Department of Nutrition and senior author of the study.

The study was pub­lished in the New England Journal of Medicine.


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