A Dutch study suggests that eating half a handful of nuts every day could substantially lower the risk of early death.
Previous studies had already indicated a link with cardiovascular health, but this is the first to look at specific nuts and diseases.
Maastricht University researchers found a 23% lower chance of death during the 10-year study in people eating at least 0.3oz (10g) of nuts or peanuts a day.
There was no benefit for peanut butter, which is high in salt and trans fats.
More than 120,000 Dutch 55-to-69-year-old men and women provided dietary and lifestyle information in 1986, and then their mortality rate was looked at 10 years later.
The premature mortality risk due to cancer, diabetes, respiratory and neurodegenerative diseases was lower among the nut consumers.
There was an average 23% lower risk of 10-year mortality across all diseases, with a decrease of: 45% for neurodegenerative disease, 39% for respiratory disease, 30% for diabetes.
Prof. Piet van den Brandt, who led the study, published in the International Journal of Epidemiology, said: “It was remarkable that substantially lower mortality was already observed at consumption levels of 15g of nuts or peanuts on average per day.”
The researchers had taken into account the mitigating factor that nut consumers ate more fruit and vegetables and that women who ate nuts were often leaner, and adjusted the results accordingly, Prof. Piet van den Brandt said.
Nuts contain monounsaturated and polyunsaturated fatty acids, various vitamins, fiber, antioxidants and other bioactive compounds.
A new research suggests that a diet rich in vitamins and fish may protect the brain from ageing while junk food has the opposite effect.
Elderly people with high blood levels of vitamins and omega 3 fatty acids had less brain shrinkage and better mental performance, a Neurology study found.
Trans fats found in fast foods were linked to lower scores in tests and more shrinkage typical of Alzheimer’s.
A UK medical charity has called for more work into diet and dementia risk.
The best current advice is to eat a balanced diet with plenty of fruit and vegetables, not smoke, take regular exercise and keep blood pressure and cholesterol in check, said Alzheimer’s Research UK.
The research looked at nutrients in blood, rather than relying on questionnaires to assess a person’s diet.
US experts analyzed blood samples from 104 healthy people with an average age of 87 who had few known risk factors for Alzheimer’s.
They found those who had more vitamin B, C, D and E in their blood performed better in tests of memory and thinking skills. People with high levels of omega 3 fatty acids – found mainly in fish – also had high scores. The poorest scores were found in people who had more trans fats in their blood.
Trans fats are common in processed foods, including cakes, biscuits and fried foods.
The researchers, from Oregon Health and Science University, Portland; Portland VA Medical Center; and Oregon State University, Corvallis, then carried out brain scans on 42 of the participants.
They found individuals with high levels of vitamins and omega 3 in their blood were more likely to have a large brain volume; while those with high levels of trans fat had a smaller total brain volume.
Study author Gene Bowman of Oregon Health and Science University said: “These results need to be confirmed, but obviously it is very exciting to think that people could potentially stop their brains from shrinking and keep them sharp by adjusting their diet.”
Co-author Maret Traber of the Linus Pauling Institute at Oregon State University said: “The vitamins and nutrients you get from eating a wide range of fruits, vegetables and fish can be measured in blood biomarkers.
“I’m a firm believer these nutrients have strong potential to protect your brain and make it work better.”
Commenting on the study, Dr. Simon Ridley, head of research at Alzheimer’s Research UK, said:
“One strength of this research is that it looked at nutrients in people’s blood, rather than relying on answers to a questionnaire.
“It’s important to note that this study looked at a small group of people with few risk factors for Alzheimer’s disease, and did not investigate whether they went on to develop Alzheimer’s at a later stage.
“There is a clear need for conclusive evidence about the effect of diet on our risk of Alzheimer’s, which can only come from large-scale, long-term studies.”
