How eating too many sausages could raise the risk of dementia

It is well known that eating too much processed meat is linked to bowel cancer.

Now there is evidence it may also contribute to dementia.

More than 133,000 people were analysed for up to four decades. They answered questions on their diet every two to four years to see if they developed the condition. Those consuming at least a quarter of a typical portion of processed red meat daily — roughly three ounces (two slices of bacon or a single sausage) — had a 13 per cent greater chance of developing dementia.

That was compared to people eating a minimal amount — about a tenth of a portion.

Based on the difference, the study concluded someone could cut their risk of getting dementia by 28 per cent by replacing a portion a day of processed red meat with the same amount of fish.

The risk could be cut by 16 per cent if they switched to poultry instead. By switching to nuts and legumes, such as lentils and beans, their risk of the disease would reduce by 19 per cent.

Dr Daniel Wang, senior author of the Harvard study, said: “We found processed red meat may increase the risk of cognitive decline and dementia, but the good news is that it also found that replacing it with healthier alternatives, like nuts, fish and poultry, may reduce a person’s risk.”

Processed red meat contains nitrites which are added as preservatives. These may cause molecules called free radicals to damage the brain.

The high salt content of bacon and hot dogs can also lead to high blood pressure — damaging blood vessels, reducing blood flow to the brain and leading to vascular dementia — the second most common type of the disease.

The study, published in the journal Neurology, looked at data on health professionals in the US who signed up for research studies in their middle age.

Almost 12,000 of these people — roughly one in ten — developed dementia.

Cognitive function assessments were done on around 17,500 women. The results suggested someone’s brain was about 20 months older for every extra portion of processed red meat they ate per day.

Researchers also analysed self-reported cognitive problems. These are less reliable than an expert assessment, but people who report thinking problems are often right about them and later diagnosed with cognitive decline or dementia.

The results also suggest too much unprocessed red meat, such as beef and lamb, might have an effect on thinking skills. Self-reported cognitive decline was 16 per cent more likely in people eating at least one daily portion of unprocessed red meat, compared to those eating less than half.

However, no increased risk of dementia was found linked to unprocessed red meat.