World Health Matters: The Netherlands: Nuts may protect against major causes of death

by Gary Finnegan: Peanut and nut intake appear to lower mortality rates from major diseases, according to a new study, but peanut butter has no shown any protective effect.

The study, published in the International Journal of Epidemiology confirms earlier findings that nut consumption can have a positive effect on cardiovascular risk. It found that men and women who eat at least 10 grams of nuts or peanuts per day have a lower risk of dying from several major causes of death than people who do not consume nuts or peanuts.

The reduction in mortality was strongest for respiratory disease, neurodegenerative disease, and diabetes, followed by cancer and cardiovascular diseases. The effects are equal in men and women, according to the research conducted at Maastricht University.

This study was carried out within the Netherlands Cohort Study, which has been running since 1986 among over 120,000 Dutch 55-69 year old men and women. Nut consumption was assessed by asking about portion size and frequency of intake of peanuts, other nuts (tree nuts), and peanut butter. The researchers analysed the relationship with overall and cause-specific mortality since 1986.

Project leader and epidemiologist Professor Piet van den Brandt said the impact was stronger than expected. “It was remarkable that substantially lower mortality was already observed at consumption levels of 15 grams of nuts or peanuts on average per day – half a handful,” he said.

The benefits appear to plateau with higher intake as no additional benefit was associated with eating greater quantities of nuts.

Peanuts and tree nuts both contain various compounds such as monounsaturated and polyunsaturated fatty acids, various vitamins, fibre, antioxidants, and other bioactive compounds, that possibly contribute to the lower death rates.

In contrast to peanuts, no association was found between peanut butter intake and mortality risk. However, besides peanuts, peanut butter contains also added components like salt and vegetable oils. In the past, it has been shown that peanut butter contains trans fatty acids and therefore the composition of peanut butter is different from peanuts. The adverse health effects of salt and trans fatty acids could inhibit the protective effects of peanuts, according to the researchers.