“Veg diet key to living longer,” reports today’s Daily Express front page headline.
Its story is prompted by a large, well-designed, long-term study into vegetarian dietary patterns and their effects on reported mortality (death). The main finding was that vegetarians had a 12% reduction in the risk of death from any cause compared with non-vegetarians.
However, the researchers’ definition of ‘vegetarian’ was quite broad and may horrify some vegetarians as it included people who ate meat and fish once a week or less. Dietary patterns were only measured at the start of the study, and these can change over time. The study also had a relatively short follow-up to determine whether dietary patterns might affect the risk of death.
It’s also worth noting that vegetarians tended to live healthy lifestyles, and this could have influenced the results.
While this study cannot show direct cause and effect between diet and death risk, it highlights an important point. Even if you do not want to stop eating meat there is plenty you can ‘borrow’ from the ‘vegetarian lifestyle’ to improve your health, such as eating plenty of fresh fruit and vegetables.
Where did the story come from?
The study was carried out by researchers from Loma Linda University, California and was funded by the US National Cancer Institute and National Institute of Food and Agriculture. It was published in the peer-reviewed journal, JAMA Internal Medicine.
The results of the research were generally well covered in the media. However, the Mail Online website presented speculation as fact in its headline: it states that people who avoid meat have better health due to low blood pressure. Although this is a possible and plausible explanatory factor, the current study did not investigate the blood pressure of vegetarians.
What kind of research was this?
This was a prospective cohort study set in the US that aimed to evaluate the association between vegetarian dietary patterns and mortality (death).
A cohort study is the ideal study design to address this question. However, cohort studies cannot show cause and effect, as it is possible that other factors (confounders) are responsible for the associations seen. Ideally, the effects of a particular diet on a clinical outcome would be assessed through a randomised controlled trial. However, this is unlikely to be feasible when investigating an outcome such as mortality, which would need a long duration of follow-up; and also it would be difficult to randomise people to eating meat, or not eating meat, which comes down to personal choice.
Source: Read More at NHS