Studies suggest that pesco-vegetarian diets are best at reducing the risk of death in older people

Various vegetarian diets appear to protect against the risk of death and related diseases. A pesco-vegetarian diet – which includes fish – offers the greatest protection against the risk in very old people, according to a new study.

The study “Cause-Specific and All-Cause Mortality in Vegetarian and Non-Vegetarian Participants of the Adventist Health Study-2 Cohort” was published on August 2 in the American Journal of Clinical Nutrition.

Researchers at Loma Linda University Health found that vegetarian diets were associated with a lower risk of all-cause mortality and many cause-specific deaths, particularly among men and middle-aged individuals. However, slightly higher risks of neurological diseases such as stroke, dementia and Parkinson's disease were observed among very old vegetarians.

Nevertheless, the pesco-vegetarian diet continued to offer a small but noticeable advantage over other vegetarian and non-vegetarian diets, even in older people.

Gary Fraser, MBCHB, Ph.D., distinguished professor at Loma Linda University School of Public Health and lead researcher on the study, said a vegetarian diet appears to protect against death risk into middle age. However, once the diet begins to help people over 80, this overall benefit appears to disappear for those on a strict vegetarian diet.

“These increased risks of neurological disease among vegetarians in their 80s were not enormous, but there is something going on that we should not ignore if we want the vegetarian benefit to be maintained for all vegetarians in their later years,” Fraser said.

The study used data from the Adventist Health Study-2, a massive cohort of nearly 96,000 people who identify as Seventh-day Adventists and lived in the United States and Canada during study enrollment between 2002 and 2007 (with follow-up through 2015). Data from this group have been used in numerous studies of health, disease, and mortality over the years.

This study analyzed data from more than 88,000 subjects and about 12,500 deaths in the study cohort. Dietary data were collected using a questionnaire and then categorized into five patterns: non-vegetarian, semi-vegetarian, pesco-vegetarian, lacto-ovo-vegetarian, and vegan.

Fraser said his team found that Adventist vegetarians overall had about a 12 percent lower risk of death than Adventist non-vegetarians. Study participants on a pesco-vegetarian diet had an 18 percent lower risk of death.

People with a lacto-ovo vegetarian diet (including dairy products and eggs) had a 15% lower risk of death. Vegans had an overall lower risk of death of less than 3%, but male vegans fared much better than non-vegetarians, unlike women.

“Overall, this is the clearest data that American vegetarians are better protected against premature death than non-vegetarians,” Fraser said.

Provided by Adventist Health Sciences Center at Loma Linda University