Thousands follow a vegetarian diet in the hope that it will improve their health.
But throwing away meat and fish could prove harmful later in life, especially when it comes to the risk of dementia, new US research shows.
Scientists at Loma Linda University Health in California found that most vegetarian diets are associated with a lower risk of disease in middle-aged people. However, the opposite was the case among people over 65.
Researchers found slightly higher risks of conditions such as stroke, dementia and Parkinson’s disease among very elderly vegetarians.
However, when fish was added to the diet, that risk was significantly reduced – and associated with the lowest risk of death.
Researchers found slightly higher risks of conditions such as stroke, dementia and Parkinson’s disease among very elderly vegetarians. But when fish was added to the diet, that risk was reduced
The studypublished in August in the American Journal of Clinical Nutrition, used dietary data from 88,000 people aged 30 to 85 from Canada and the US, including 12,500 deaths. Participants were recruited between 2002 and 2007 and followed up in 2015.
Participants were divided into five categories based on their diet: non-vegetarian, semi-vegetarian, pesco-vegetarian (those who ate fish), lacto-ovo-vegetarian (those who ate dairy and eggs) and vegan.
Overall, those who ate a vegetarian diet had about a 12 percent lower risk of dieting compared to meat eaters.
But people who ate a vegetarian diet but also ate fish (pesco-vegetarian) had an 18 percent lower risk of death.
Researchers also looked at the benefit of adding dairy and eggs to a vegetarian diet and found that the diet reduced the risk of death by an additional 15 percent.
The Mediterranean diet, which also includes eating a variety of fruits and vegetables and fatty fish such as salmon and mackerel, is believed to be beneficial because it is high in antioxidants.
Vegans, who do not eat animal products, had only a three percent lower risk of death.
However, the study found that while the vegetarian diet offered protection against the risk of death for middle-aged people, people in their 80s did not see as much benefit.
Lead researcher on the study, Professor Gary Fraser, explained that there is an increased risk of neurological disorders among vegetarians over the age of 80.
This may be because a vegetarian diet without fish lacks essential nutrients, such as fatty acids, that can help the brain.
The Mediterranean diet, which also includes eating a variety of fruits and vegetables and fatty fish such as salmon and mackerel, is believed to be beneficial because it is high in antioxidants.
The Alzheimer’s Society suggests this may help protect against some of the damage to brain cells associated with Alzheimer’s disease.
Adding fatty fish, which are rich in omega-3, can also promote brain health.
That’s because omega-3, also a type of fat found in cell membranes, is important for your brain from development in the womb through adulthood.
It is thought that omega-3s may help reduce inflammation and oxidative stress, both of which contribute to the development of Alzheimer’s disease and dementia.
Omega-3 can also be found in eggs, nut seeds and walnuts, but in much lower amounts than in oily fish, according to the British Dietetic Association.