Thousands of people adopt a vegetarian diet in the hope that it will improve their health.
But giving up meat and fish can be harmful in old age, particularly in terms of dementia risk, 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, in the case of those over 65 years of age, the opposite occurred.
The researchers observed slightly increased risks among very old vegetarians for diseases such as stroke, dementia and Parkinson’s disease.
However, when fish was added to the diet, that risk was significantly reduced and was associated with the lowest risk of death.
The researchers observed slightly increased risks among very old vegetarians for diseases such as stroke, dementia and Parkinson’s disease. But when fish was added to the diet, that risk was reduced
He studywhich was published in August in the American Journal of Clinical Nutrition, used dietary data from 88,000 people aged 30 to 85 in Canada and the US, including 12,500 deaths. Participants were recruited between 2002 and 2007 and followed up in 2015.
Participants were separated into five categories based on their diet: non-vegetarians, semi-vegetarians, pesco-vegetarians (those who ate fish), lacto-ovo-vegetarians (those who ate dairy and eggs) and vegans.
Overall, those who followed a vegetarian diet had about a 12 percent lower risk of dieting compared to those who ate meat.
But people who followed a vegetarian diet but also ate fish (pesco-vegetarian) had an 18 percent lower risk of death.
The researchers also looked at the benefit of adding dairy and eggs to a vegetarian diet and found that this diet reduced the risk of death by an additional 15 percent.
The Mediterranean diet, which also includes eating a variety of fruits and vegetables as well as oily fish such as salmon and mackerel, is believed to be beneficial because it is rich in antioxidants.
Vegans, who do not eat any animal products, only had a three percent lower risk of death.
However, the study found that although the vegetarian diet offered protection against the risk of death for middle-aged people, those in their 80s did not see as much benefit.
The study’s lead researcher, Professor Gary Fraser, explained that there is an increased risk of neurological diseases among vegetarians aged 80.
This could be because a vegetarian diet that does not include fish could lack vital nutrients, such as fatty acids, which can help the brain.
The Mediterranean diet, which also includes eating a variety of fruits and vegetables as well as oily fish such as salmon and mackerel, is believed to be beneficial because it is rich in antioxidants.
The Alzheimer’s Society suggests that this may help protect against some of the damage to brain cells associated with Alzheimer’s disease.
Adding oily fish, rich in omega-3, could also help brain health.
This is because omega-3, which is also a type of fat found in cell membranes, is important for the brain from development in the womb to adulthood.
It is believed that omega-3 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, dried fruit seeds and walnuts, but at much lower levels than oily fish, according to the British Dietetic Association.