Legumes and soy foods may help reduce hypertension risk

A higher dietary intake of soy and legumes is linked to a lower risk of high blood pressure, finds a pooled data analysis of the available evidence, published in the open access journal BMJ Nutrition Prevention & Health.

And the optimal daily amount may be around 170 g of legumes, which include peas, lentils, chickpeas and beans, and 60 to 80 g of soy foods, examples of which include tofu, soy milk, edamame, tempeh, and miso, the findings indicate.

Legumes and soy foods have been associated with an overall lower risk of cardiovascular disease, but the evidence on their potential for lowering high blood pressure is mixed and needs to be systematically quantified, explain the researchers.

To explore this further, the researchers scoured databases for relevant studies published up to June 2025, and found 10 publications that included data from 12 prospective observational studies.

Five studies were from the USA, 5 from Asia (China, Iran, South Korea and Japan), and 2 were from Europe (France and the UK). Nine studies included both men and women, 2 included only women, and 1 included only men.

The number of study participants ranged from 1152 to 88,475 and the number of cases of high blood pressure ranged from 144 to 35,375.

Pooled data analysis of the study findings showed that higher daily intake of legumes and soy foods was associated with a lower risk of developing high blood pressure.

Compared with those with a low intake of legumes, those with a high intake were 16% less likely to develop high blood pressure. Similarly, those with a high intake of soy foods were 19% less likely to develop the condition than those with a low intake.

When assessing the association between quantity and lower risk, a linear reduction (30%) emerged for legumes up to around 170 g/day, while most of the reduction in risk (28-29%) for soy foods was observed at between 60 and 80 g/day, with no further reduction in risk at higher intake.

One hundred grams of legumes/soy is equivalent to a serving size of about one cup or 5–6 tablespoons of cooked beans, peas, chickpeas, lentils, soybeans or a palm-size serving of tofu, explain the researchers.

Using World Cancer Research Fund evidence grading criteria for evaluating the likelihood of causality, the researchers consider the overall evidence to indicate a probable causal relationship between both legume and soy intake and a reduced risk of high blood pressure.

There are plausible explanations for the findings, they say. Legumes and soy are high in potassium, magnesium, and dietary fiber, all of which are known for their blood pressure lowering properties.

And recent research has suggested that the fermentation of soluble fiber from legumes and soy produces short-chain fatty acids that influence blood vessel dilation, while the isoflavone content of soy also seems to help lower blood pressure, they explain.

The researchers acknowledge various limitations to their findings, including the variability of the studies in the pooled data analysis. This included differences in legume types, levels of intake, preparation methods, dietary contexts, and the definition of high blood pressure.

"Despite these limitations, the findings of this meta-analysis have major public health implications, given the alarming global increase in hypertension prevalence," they point out.

"Current legume consumption across Europe and the UK remains below dietary recommendations, with average intakes of only 8–15 g/day, far below the recommendations of 65 to 100 g/day recommended for overall cardiovascular health," they add.

"Although further large-scale cohorts are needed for confirmation, these findings provide further evidence in support of dietary recommendations to the public to prioritise and integrate legumes and soy foods as healthy protein sources in the diet," they conclude.

"This research strengthens the evidence base for the cardioprotective benefits of plant-based diets. The authors have significantly added to the case for using legumes and soy as primary dietary strategies to mitigate the global burden of hypertension," comments Professor Sumantra Ray, chief scientist and executive director of NNEdPro Global Institute for Food, Nutrition and Health, which co-owns BMJ Nutrition Prevention & Health.

"The strengths of the study lie in its rigorous dose-response analyses, which offer practical dietary targets for use in public health guidelines and clinical practice. But we can't entirely rule out the influence of unmeasured influential factors. And the plateauing of benefits for soy at 60–80 g/day warrants further investigation, as it remains unclear if this reflects a true biological limit or is a byproduct of the smaller number of studies available for analysis."