1.5 Cups of Leafy Greens a Day Could Prevent Heart Disease in Older Adults

A new study has found that older women with a higher intake of vitamin K1—found in green vegetables such as spinach, broccoli, cabbage, bok choy, and kale—may have a lower long-term risk of heart attack and stroke. All it may take is adding 1 to 1.5 cups of these vegetables to your diet.

What the Research Says

The study, published in the European Journal of Nutrition, followed over 1,400 Australian women aged 75 for 14.5 years.

It found that those with the highest vitamin K1 intake, equivalent to about one raw cup or 0.5 cup of cooked leafy greens, had a:

• 43% lower risk of dying from atherosclerotic vascular diseases (ASVDs), such as heart attack and stroke, compared to those with the lowest vitamin K1 intake
• 29% lower risk of experiencing a heart attack and stroke
• 5.6% reduction in atherosclerosis without symptoms

Vitamin K1 may have this effect because it activates matrix GLA protein, which inhibits vascular calcification, a common attribute of ASVDs.

“An exciting take-home is that these quantities of vitamin K1 can be consumed easily each day by adding roughly one cup of these vegetables to your normal meals, which could be a low-risk strategy to potentially optimize cardiovascular health,” said lead study author Montana Dupuy, BSc. Hons., a PhD candidate and research assistant at the Nutrition & Health Innovation Research Institute at Edith Cowan University.

Caveats to the Study

The study participants were older, mostly Caucasian women living in Western Australia. This means the findings may not apply to the general population. The study is also observational in nature, so it doesn’t establish direct causality.

Do Vitamin K1 Supplements Have The Same Effect?

The study looked at dietary sources of vitamin K1 specifically, so it’s unclear whether vitamin K1 supplements would have the same effect.

While one small trial found that high-dose vitamin K1 supplementation reduced vascular calcification in people with diabetes the broader evidence base is limited. said Lina Begdache, PhD, RDN, a dietitian-nutritionist and associate professor of health and wellness studies at Binghamton University.

Dietary vitamin K1 comes packaged with other nutrients and bioactive compounds that likely contribute to its protective effects, Begdache added. And supplements may not be absorbed by the body as efficiently as food, especially if they’re not taken with dietary fat.

“In general, prioritizing whole-food sources is recommended over supplements, unless guided by a healthcare provider,” she said.

Vitamin K1 Could Be Great for Heart Health

While the idea that vegetables are good for cardiovascular health is not new, Begdache said the strength and specificity of these findings are noteworthy.

Previous research on vitamin K’s role in heart health produced mixed results, often confounded by inconsistent dietary data or a focus on vitamin K2.

She said this study stands out for its use of region-specific dietary assessments and long-term health records, providing robust evidence that vitamin K1 alone has independent, protective cardiovascular effects in older women.

That’s important because cardiovascular diseases remain the leading cause of death globally, and older women are particularly vulnerable.

“Our message from this research is to encourage people to look for these green vegetables the next time you’re at the grocery store and get creative in incorporating some of them into daily meals,” Dupuy said. “This is a very easy strategy to increase your vitamin K1 and total vegetable intake, which could be beneficial for heart and blood vessel health.”