Cruciferous vegetables—such as broccoli, cabbage, kale, and cauliflower—lower blood pressure than root vegetables and squash in middle-aged and older adults with high blood pressure, a study has found.
Which vegetables are best for heart health?
Researchers from Australia’s Edith Cowan University found that eating four servings a day of cruciferous vegetables led to a significant reduction in blood pressure compared to eating four servings a day of root vegetables and squash vegetables such as carrots, potatoes, sweet potatoes and pumpkin. The results of the study were published in the journal BMC Medicine on September 2.
“Compounds called glucosinolates, which are found almost exclusively in cruciferous vegetables, have been shown to lower blood pressure in animals, but evidence for this in humans has been limited until now,” said Edith Cowan University PhD student Emma Connolly.
She added, according to the Eurek Alert website: “Cruciferous vegetables also contain several other components that may provide additional benefits in lowering blood pressure, such as nitrates and vitamin K.”
She explained that increasing vegetable intake is widely recommended to reduce the risk of heart disease, and previous studies have shown that cruciferous vegetables such as broccoli, cabbage and Brussels sprouts have a stronger association with reduced risk of heart disease than other vegetables. However, despite these vegetables being consumed globally, cruciferous vegetables typically make up a small portion of total vegetable consumption.
Dr Lauren Bleckenhorst, lead researcher at Edith Cowan University and fellow of the Australian Heart Foundation, said that less than 1 in 15 Australian adults currently meet the recommendations for vegetable intake, and that figure has continued to decline over the years.
“Cruciferous vegetables are the least consumed group of vegetables. If people can increase their intake of this group of vegetables, they will get greater benefits in terms of lowering blood pressure and reducing the risk of heart disease in the future,” she said.
Human experiment
The study was conducted over a period of 6 weeks, with participants completing two 2-week diet periods, separated by two weeks of their usual diet.
During one intervention period, participants ate 4 servings (a serving equals 1 cup raw or 1/2 cup cooked) of cruciferous vegetables daily as soup with lunch and dinner, while during the other intervention period, they ate root vegetable and squash soup. Participants’ blood pressure was measured continuously for 24 hours before and after both intervention periods, and results showed a 2.5 mmHg difference in blood pressure reduction for cruciferous vegetables compared to root vegetables and squash.
The participants’ diet and lifestyle remained constant throughout the study, suggesting that the reduction in blood pressure was not influenced by these factors.
This drop in blood pressure can translate into about a 5% reduction in the risk of heart attack or stroke.
The Australian Heart Foundation welcomed the research findings, with Kim Lang, director of the Heart Health Program, saying the findings were interesting.
“The Heart Foundation encourages people to eat a variety of vegetables daily as part of a heart-healthy diet. You can try adding cruciferous vegetables, such as broccoli or cabbage, to your meals,” she added.