Issue 21 / 11 June 2013

VEGETARIANS can look forward to lower all-cause mortality compared with non-vegetarians, according to US research, but clinicians should stop short of encouraging all patients to become vegetarian, says leading Australian nutritionist Dr Rosemary Stanton.

Dr Stanton said a better option was to encourage patients to eat more plant foods and reduce the quantity of meat consumed.

“Trying to tell everyone that you have to be a vegetarian, you lose most people”, Dr Stanton told MJA InSight, after research published in JAMA Internal Medicine found a 12% reduction in all-cause mortality in vegetarians compared with non-vegetarians (adjusted hazard ratio [HR], 0.88 [95% CI; 0.80‒0.97]). (1)

Vegetarianism was also associated with lower cardiovascular, renal and endocrine mortality, the study found. The results appeared to be more robust in males than in females.

The prospective cohort study of more than 70,000 Seventh-day Adventist men and women in North America analysed the diets of five groups ― non-vegetarians, semi-vegetarians (consumed fish and non-fish meats occasionally), pesco-vegetarians (consumed fish), lacto-ovo-vegetarians (consumed dairy foods and eggs) and vegans.

Of these groups, pesco-vegetarians showed the greatest reduction in all-cause mortality during the mean follow-up time of 5.79 years (HR, 0.81 [95% CI, 0.69‒0.94]), followed by vegans (HR, 0.85 [95% CI, 0.73‒1.01]).

Angela Saunders, senior dietician at Sanitarium Health and Wellbeing, which is owned by the Seventh-day Adventist Church, said the beauty of the study cohort (n = 96 000) was that in a typical North American Seventh-day Adventist community, about half are vegetarian and half are non-vegetarian.

“The real strength of this large cohort is that the researchers can compare vegetarians with non-vegetarians who have an overall similar lifestyle and can therefore look particularly at the contribution diet makes to health”, Ms Saunders told MJA InSight.

She said that the study affirmed what was already known about the health benefits and lower mortality associated with a vegetarian diet.

“Many studies have shown us that a whole dietary pattern that emphasises plant foods that are minimally processed ― like whole grains and legumes, nuts, fruits and vegetables ― [is] particularly helpful for reducing chronic disease”, Ms Saunders said.

Dr Stanton said as vegetarian diets became more common, it was increasingly important to focus on the quality of the foods consumed.

“You can have what I call a ‘chocolate, chips and cola diet’― all vegetarian products and really junky”, Dr Stanton said.

“The advantage of this Seventh-Day Adventist group is that they don’t fall into that ‘chocolate, chips and cola’ type thing”, she said.

“So it’s not the term vegetarian that makes [a diet] healthy, it’s the common foods that are consumed in these studies of vegetarian groups ― the plant foods, nuts, seeds, vegetables, legumes, whole grains and fruit.”

Dr Stanton also said she could find no evidence that adding a small amount of non-processed meat to a largely plant-based diet was harmful.

“What we need to guard against are the large amounts of red meat and probably any amount of processed meat”, she said.

This was the message contained in the NHMRC’s recently released Australian Dietary Guidelines, said Dr Stanton, who sat on the dietary guidelines working committee. (2)

In addition to health benefits, the environmental benefits of a vegetarian diet were highlighted in an editorial accompanying the US research. (3)

“A growing body of literature points to the negative environmental impact of meat, particularly meat produced from industrial farm animals”, the author wrote.

“This may turn out to be a stronger motivation to decreasing meat intake for many than even the potential health benefits.”

Dr Stanton agreed that environmental concerns could be an important driver in improving dietary habits.

“I think there’s a real change coming. People want to know where their animal foods come from and how the animal was treated”, she said.

 

1. JAMA Intern Med 2013; 3 June (online)
2. NHMRC 2013; Australian Dietary Guidelines
3. JAMA Intern Med 2013; 3 June (online)
 

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