Eating more vegetables is widely recommended to lower the risk of heart disease. Cruciferous vegetables (e.g., arugula, bok choy, broccoli, Brussels sprouts, cabbage, cauliflower, collard greens, horseradish, kale, radish, turnips, and watercress) are known for their cancer-fighting properties. They also have heart health benefits. Although eaten worldwide, they comprise only a small portion (5–24%) of total vegetable intake. Studies have shown that eating more cruciferous vegetables is linked to a lower risk of heart disease (1).
High blood pressure is a major risk factor for heart disease and becomes more common with age. Cruciferous vegetables contain glucosinolates, which have been shown to lower blood pressure in animals, but human studies are limited. These vegetables may also benefit heart health by improving blood sugar control and blood vessel function and slowing plaque buildup in arteries. Other nutrients in cruciferous vegetables, like nitrate and vitamin K, may also help regulate blood pressure (1).
Few studies have tested the effects of cruciferous vegetables on heart disease risk factors in humans. The VEgetableS for vaScular hEaLth (VESSEL) study done in Australia aimed to see if eating these cruciferous vegetables daily could lower blood pressure in middle-aged and older adults with slightly high blood pressure compared to eating root and squash vegetables. Researchers expected cruciferous vegetables to lower blood pressure more effectively. They also examined whether these vegetables improved other blood pressure measures, artery health, and markers of inflammation and oxidative stress (1).
In this randomized, controlled, crossover study, 18 participants (66-70 years old) with mild to moderately elevated blood pressure (SBP 120–160 mmHg, and diastolic (DBP) < 100 mmHg) followed two diets for two weeks each, with a two-week break. One diet included cruciferous vegetables, and the other included root and squash vegetables (about 300g/day). Participants didn’t know which diet was the test or the control. Researchers tracked food intake and measured blood pressure before and after each diet (1).
Participants completed two 2-week dietary interventions in random order, as follows:
Intervention: Four servings (~ 300 g/day) of cruciferous vegetables (broccoli, kale, cauliflower, and cabbage) were consumed as two soups: one at lunch and one at dinner (~ 600 mL soup/day, ~ 600 kJ/day).
Control: Four servings (~ 300 g/day) of root and squash vegetables (potato, sweet potato, carrot, and pumpkin) were consumed as two soups, one at lunch and one at dinner (~ 600 mL soup/day, ~ 600 kJ/day).
The intervention soup contained 40% broccoli, 25% cauliflower, 25% cabbage, and 10% kale, and the control soup contained 40% potato, 30% pumpkin, 20% carrot, and 10% sweet potato. Root and squash vegetables were chosen as the control intervention as these vegetables are commonly consumed in Australia.
Most participants followed the diets closely (72% had full adherence). Blood markers confirmed the difference between diets. Eating cruciferous vegetables significantly lowered 24-hour blood pressure (-2.5 mmHg), mainly due to a reduction in daytime blood pressure (-3.6 mmHg). Triglyceride levels were also slightly lower (1).
This study found that eating four servings of cruciferous vegetables per day significantly lowered blood pressure compared to eating the same amount of root and squash vegetables. A 2.5 mmHg drop in blood pressure may reduce the risk of major heart-related events by about 5%, based on previous research showing that a 5 mmHg reduction lowers risk by 10%. Eating more cruciferous vegetables reduced blood pressure compared to root and squash vegetables. (1).
Hypertension during pregnancy can have serious consequences for both the mother and baby. For the mother, it increases the risk of preeclampsia, a condition that can lead to organ damage, and eclampsia, which causes seizures and can be life-threatening. High blood pressure also raises the risk of stroke, heart disease, and placental abruption, where the placenta separates from the uterus too early, leading to heavy bleeding. For the baby, hypertension can result in preterm birth, low birth weight, and stillbirth due to reduced oxygen and nutrient supply. It may also impact the baby’s brain and organ development, leading to long-term health issues.
Proper management through lifestyle changes, therapies, and close monitoring is essential to reduce these risks and ensure a healthier pregnancy outcome. Recently, sulforaphane, a powerful antioxidant and anti-inflammatory agent found in broccoli and other cruciferous vegetables, has been suggested as a treatment for preeclampsia.
Sulforaphane was tested in pregnant and non-pregnant women to see if it may lower blood pressure. In six healthy women, the absorption of sulforaphane from two types of broccoli extracts, one activated and one non-activated, was compared. The activated extract led to significantly higher sulforaphane levels. Then, increasing doses of the activated extract were tested in 12 women with pregnancy-related high blood pressure (2).
Preeclamptic women absorbed less sulforaphane from the same dose than non-pregnant women. However, doubling the dose improved absorption. The activated extract also modestly lowered diastolic blood pressure (p = 0.05) and reduced certain harmful blood markers linked to preeclampsia (2).
Overall, activated broccoli extract allows for better absorption of sulforaphane than the non-activated version. Pregnant women may require higher doses to experience the benefits, which can include improved blood vessel function and reduced blood pressure (2).
Radish is a cruciferous vegetable, and its leaves have antioxidant and anticancer properties. One study tested their effects on high blood pressure in rats. Researchers gave radish leaf extract (0, 30, or 90 mg/kg) to hypertensive rats for five weeks, while normal rats served as controls. The extract did not affect body weight but helped lower blood pressure, especially at 90 mg/kg, where it dropped from 214 mmHg to 166 mmHg in three weeks. The extract did not impact the angiotensin-converting enzyme (ACE) activity but increased nitric oxide levels and antioxidant enzyme activity. Sodium and potassium levels in the blood remained unchanged, but their levels in feces increased. These results suggest that radish leaves may help reduce high blood pressure by boosting nitric oxide and antioxidant activity (3).
Nitric oxide in the blood helps protect against artery diseases and may play a role in high blood pressure. It is made from L-arginine by nitric oxide synthase and helps widen blood vessels while preventing blood clots and muscle cell growth. Studies show that L-arginine supplements can reduce artery blockage. Hypertensive patients usually have low nitric oxide levels, but in this study, there was no difference between normal and hypertensive rats. Nitric oxide also helps lower ACE production. This study found that radish leaf extract increased nitric oxide levels in the blood and had a positive effect on high blood pressure (3).
The consumption of cruciferous vegetables offers promising benefits for blood pressure management and overall heart health. While studies suggest a significant reduction in blood pressure among those who regularly include these vegetables in their diet, particularly in older adults with mild to moderate hypertension, further research is needed to fully understand the underlying mechanisms and long-term effects. Given the potential risks associated with high blood pressure, especially during pregnancy and later in life, incorporating more plant-based foods rich in antioxidants, like cruciferous vegetables, may be a valuable strategy for improving cardiovascular health.
References:
1. Connolly EL, Liu AH, Radavelli-Bagatini S, Shafaei A, Boyce MC, Wood LG, McCahon L, Koch H, Sim M, Hill CR, Parmenter BH, Bondonno NP, Devine A, Croft KD, Mithen R, Gan SK, Schultz CJ, Woodman RJ, Bondonno CP, Lewis JR, Hodgson JM, Blekkenhorst LC. Cruciferous vegetables lower blood pressure in adults with mildly elevated blood pressure in a randomized, controlled, crossover trial: the VEgetableS for vaScular hEaLth (VESSEL) study. BMC Med. 2024 Sep 2;22(1):353. doi: 10.1186/s12916-024-03577-8. PMID: 39218859; PMCID: PMC11367748.
2. Langston-Cox AG, Anderson D, Creek DJ, Palmer KR, Marshall SA, Wallace EM. Sulforaphane Bioavailability and Effects on Blood Pressure in Women with Pregnancy Hypertension. Reprod Sci. 2021 May;28(5):1489-1497. doi: 10.1007/s43032-020-00439-5. Epub 2021 Jan 6. PMID: 33409874.
3. Chung DH, Kim SH, Myung N, Cho KJ, Chang MJ. The antihypertensive effect of ethyl acetate extract of radish leaves in spontaneously hypertensive rats. Nutr Res Pract. 2012 Aug;6(4):308-14. doi: 10.4162/nrp.2012.6.4.308. Epub 2012 Aug 31. PMID: 22977684; PMCID: PMC3439574.
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