Eating a handful of nuts daily may cut the risk of hypertension by about 20 per cent, a new analysis involving more than 143,000 people has found.

The study, published in the British Journal of Nutrition, examined the association between nut consumption and the risk of hypertension, with researchers finding that higher nut intake was significantly associated with a lower risk of developing the condition.

According to the World Health Organisation (WHO), Hypertension is a common but serious condition affecting an estimated 1.4 billion adults aged 30 to 79 globally, yet nearly half are completely unaware they have it.

The researchers noted that unhealthy dietary patterns, particularly diets low in whole grains, potassium, fruits, vegetables and nuts or seeds, but high in added sugar, sodium, sugar-sweetened beverages, and processed and red meat, are major dietary risk factors associated with hypertension.

Against this background, nuts have attracted attention for their potential cardiovascular benefits. The researchers noted that several previous meta-analyses of randomised controlled trials had reported reductions in blood pressure among people consuming nuts, although evidence on whether nut consumption directly reduces the risk of hypertension has not been entirely consistent.

To further examine the relationship, the researchers found eight prospective studies which were included in the final nut analysis, involving 143,380 participants aged between 18 and 87 years, including 20,665 people with hypertension.

Their analysis showed that participants with the highest nut consumption had a lower risk of hypertension than those with the lowest intake, while further analysis indicated an even stronger association with daily intake. They linked each 28-gram serving of nuts consumed per day to a relative risk of 0.8 for hypertension, translating to a 20 per cent lower relative risk.

The researchers also found evidence of a possible non-linear relationship between nut consumption and hypertension risk. They reported that the association appeared to flatten at around 25 to 30 grammes of nuts per day, while consumption of 30 to 35 grammes daily was associated with a modelled 26 per cent reduction in hypertension risk.

The authors subsequently noted that the results were consistent with previous meta-analyses that had reported beneficial effects of nut consumption on blood pressure and provided further support for dietary recommendations promoting increased nut consumption.

The findings, however, came with important limitations. The researchers identified potential errors in dietary measurement, the possibility of residual confounding and the fact that nut intake was mostly assessed only once at the beginning of the studies.

They also noted that the analysis did not distinguish between specific types of nuts or establish whether the nuts consumed were salted or unsalted. This was considered important because salt intake can increase blood pressure.

Another limitation was the geographical coverage of the evidence. The researchers noted that none of the studies included in the analysis was conducted in Africa or the Indian subcontinent, raising questions about how well the findings may apply to other populations and ethnic groups.

They therefore called for future research involving more diverse populations and studies examining specific types of nuts, whether they are salted, the metabolites found in nuts and the biological mechanisms that may explain their association with lower hypertension risk.