Avoid eating sausages if you want a longer life, say Harvard scientists

Replacing sausages and other meats with lentils, nuts and other plant-based proteins will significantly increase your life chances, a study has found.

The report, which examined the effects of different sources of protein, found that a high intake of protein from animal sources was associated with a higher mortality rate.

Meanwhile a high intake of protein from plant sources - such as lentils, beans and nuts - was found to be linked with a lower risk of death.

The study, conducted by researchers at the Harvard Medical School and Massachusetts General Hospital, followed more than 13,000 over 36 years, monitoring their diet, lifestyle, illness and mortality.

It found that while consuming the necessary levels of protein is important for maintaining a healthy diet, the source of protein also plays a significant role in people's health.

The research showed a 10 per cent higher intake of meat was associated with a two per cent higher mortality rate and an eight per cent higher chance of cardiovascular death.

It suggested that by switching between 15g and 19g of animal protein - the equivalent of a sausage or a few slices of bacon - for nuts, pulses, or whole grains, one can significantly cut the risk of early death.

Dr Mingyang Song, the lead scientist, from Massachusetts General Hospital and author of the report, said: “While previous studies have primarily focused on the overall amount of protein intake - which is important - from a broad dietary perspective, the particular foods that people consume to get protein are equally important.

"Our findings also have public health implications and can help refine current dietary recommendations about protein intake, in light of the fact that it is not only the amount of protein but the specific food sources that is critical for long-term health.”

The study acknowledged that the association of protein type with mortality also varied by lifestyle factors, with any significant associations restricted to participants with at least one "unhealthy behavior", such as smoking, heavy alcohol intake or obesity.

Among the healthiest participants, the association disappeared, which the researchers attributed to the fact that health-conscious people tended to eat more fish and poultry rather than red and processed meat.

Despite the varying factors the researchers concluded that more focus on protein sources in dietary recommendations could significantly improve public health.

"Although the amount and type of protein may have specific effects, [...] from a broader dietary perspective, the choice of protein sources will inevitably influence other components of diet that can in turn influence health outcomes," the report stated.

"Therefore, taking into account food sources is critical to better understand the health effect of protein intake and fine-tune dietary recommendations."