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Why women should focus on leafy greens even more after menopause

Spinach, romaine lettuce and celery are easily accessible, nitrate-rich foods.
Consuming fresh, nitrate-rich foods could improve cardiovascular health.
May 31, 2019

A team of ASU researchers found that nitrate-rich foods mitigated postmenopausal women's risk for heart disease

Though much has been done over the past few decades to raise awareness about the threat of heart disease, it continues to be the leading killer of women in the United States, accounting for roughly 1 in 5 female deaths each year, with postmenopausal women at the highest risk.

Inspired by existing research that found dietary nitrate supplementation in the form of beetroot juice improved the vascular fitness of athletes, a team of ASU researchers set out to see what high-nitrate foodsCeleriac, Chinese cabbage, endive, fennel, kohlrabi, leek and parsley are considered to be high in nitrate content, meaning they contain anywhere from 100 to more than 250 milligrams of nitrate per 100 grams of fresh produce. Celery, cress, chervil, lettuce, red beetroot, spinach and rocket (rucola) are considered to be very high in nitrate content, meaning they contain more than 250 milligrams of nitrate per 100 grams of fresh produce might do for postmenopausal women.

In their recently published study, College of Health Solutions doctoral student Selicia Mayra and professors Carol Johnston and Karen Sweazea found that postmenopausal women's increased risk for heart disease was mitigated by eating high-nitrate, leafy greens.

The message was clear, Mayra said: “Eat more salads!”

Study participants were asked to consume a salad of either spinach, romaine lettuce or celery twice daily before their normal meals, for 10 consecutive days. After a three-week washout period, they were asked to consume a low-nitrate, canned vegetable control of either beans, corn or peas before their normal meals, for 10 consecutive days.

Women’s nitrate concentration significantly increased following the salad treatment compared to the canned vegetable control, suggesting that daily ingestion of nitrate-rich, leafy green salads may prove a useful strategy for improving cardiovascular health in postmenopausal women.

ASU Now turned to Mayra and Johnston to find out what’s so great about leafy greens compared to beetroot juice and why, if you want the cardiovascular benefits of leafy greens, you should nix mouthwash altogether.

Question: Why do women have an increased risk for heart disease after menopause?

Johnston: When you look at the lifespan of an individual, men have a higher risk for heart disease early on, like in their 50s, than women. But then it flips when women go through menopause. Men have sort of a constant risk for heart disease. Women start with a lower risk and then it goes up once they hit menopause. And what happens at menopause is estrogen falls. Estrogen is a trigger of nitric oxide, which is a basal dilator, meaning it widens blood vessels, which decreases blood pressure. So women are sort of protected from heart disease for most of their lives because they have a natural way to trigger nitric oxide. But once they hit menopause, it decreases dramatically.

Q: How can eating leafy greens help?

Johnston: What's interesting about nitric oxide is you can produce it endogenously, which means your body will make it, with estrogen triggering it. But you can also provide your body with dietary nitrates that convert to nitric oxide, and leafy greens are full of nitrates.

Q: Your study notes that beetroot juice is also high in nitrates. Why didn’t you ask women to consume that instead of leafy greens?

Mayra: We wanted something that was sustainable. We wanted foods that were not only high in nitrates but also antioxidants, as well as good sources of fiber; foods that are just good for you overall. So we really wanted to move away from the bottled, prepackaged foods to real foods that people can sustainably consume over time.

Johnston: Beetroot juice is typically sold as a concentrate, and it's processed. It's not like people are eating beets. So there's a lot of processing and it's expensive. The beetroot juice craze is definitely a manufactured, novel supplement and companies are making pretty decent profits on it.

Mayra: And there's so many brands of beetroot juice and sometimes it's not regulated, so it tells you you're getting this many nitrates in there but you don't necessarily know for sure.

Q: Can everyone benefit from eating leafy greens?

Johnston: Of course. I think it's important that people eat leafy salads all the time, because they have fiber and phytochemicalsAccording to the American Institute for Cancer Research, research shows phytochemicals can influence the chemical processes inside our bodies in helpful ways. and all these wonderful things. They’re a good source of vitamin C, a good source of folate. There's a lot of antioxidants in lettuce. Epidemiological data suggests that people eat fruits and vegetables to lower their risk for cancer. But for postmenopausal women, eating leafy greens would be a strategy for avoiding high blood pressure.

Q: Is there a difference in nitrate levels between types of leafy greens?

Mayra: There is, but only slight differences. The three that we chose — spinach, romaine lettuce and celery — are some of the highest sources of nitrates.

Q: What are some other high-nitrate foods?

Johnston: Fresh beets are still at the top but we felt that these were the most easily accessible.

Mayra: Another leafy green that’s very high in nitrates is arugula.

Q: What is the major takeaway of this study?

Mayra: Eat more fresh, leafy salads.

Johnston: What’s interesting is that hypertension has a genetic component. So if you have a history of hypertension or if you have a history of heart attacks in your family, you need to do something about it. And it's nice that if you start early, you might be able to delay having to go onto pharmaceutical meds. You may need to go on meds eventually anyway; you don't play around with hypertension. But if you can keep your blood pressure under control by a simple strategy that doesn't really disrupt what you eat, that’s great. We're just saying start your meal with a salad.

Q: Was there anything people might find surprising about this study?

Mayra: Yes. We restricted mouthwash use for study participants because research has shown that antiseptic and antibacterial mouthwash sort of kill the bacteria in your mouth that's required to turn nitrates into nitrites. And nitrite is what we need because it turns into nitric oxide, which is what leads to the basal dilation. So you can eat as much nitrates and salads as you want but it won't get reduced to nitrite, and therefore, it won't get reduced to nitric oxide if you’re using mouthwash.

Top photo: Getty Images/iStockphoto

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ASU Prep graduate balanced competitive swimming with earning 4.0 GPA

ASU Prep grad to become a Sun Devil, but first is Olympic training.
May 31, 2019

After training for 2020 Olympics, elite athlete will become a Sun Devil

In addition to economics and precalculus, Jarod Arroyo has spent the last year learning a lot about balance.

Arroyo, an elite swimmer, was in the first graduating class of ASU Prep Tempe charter high school in May, finishing with a 4.0 grade point average. With high school behind him, he’ll spend the next year focusing on training for the 2020 Summer Olympics in Tokyo. After that, he’ll swim for Arizona State University.

“The key is staying on top of it and not getting behind,” Arroyo said of his life balancing school and swimming. His days started at 5 a.m., when he would swim for two hours on the ASU Tempe campus, then drive to school and go to classes, and then return to the pool for another three to four hours of swimming and conditioning. Then it was dinner, homework and mental conditioning before bed.

Arroyo, who is a member of the Puerto Rican national team, traveled frequently for competitions.

Jarod Arroyo

Jarod Arroyo (left) and Andre Arnold were the only two members of the first graduating class of ASU Prep Tempe. They were among 230 graduates of all the ASU Prep schools at the ceremony on May 24. Photo contributed by ASU Prep

“I have to be proactive,” he said.

“I went to Argentina for three weeks for the youth Olympics last fall and I got ahead on all my work and turned it in before I left and when I came back I was perfectly fine because I was proactive.

“I just have to make sure that I tell my teachers.”

In addition to working with his teachers, he was able to keep up because some of his work was done online. ASU Prep TempeThe other ASU Prep locations are in Casa Grande, south Phoenix, downtown Phoenix and on the ASU Polytechnic campus in Mesa. There are more than 3,000 students total in the ASU Prep system, not including the ASU Prep Digital online school. is a blended learning campus that infuses technology in the classroom. Arroyo, who had to take both Algebra 2 and precalculus this year, learned on the ALEKS adaptive learning platform, according to Joshua Roth, principal of ASU Prep Tempe.

“So as he gets problems right or wrong, it’s adapting to where he’s at, reinforcing things or letting him get ahead on things he does know,” Roth said. “Without that platform he wouldn’t have been able to do it.”

ASU Tempe Prep’s first graduating class included Arroyo and Andre Arnold, who became good friends.

With only 48 students, the underclassmen looked up to the two seniors, Roth said.

“Jarod’s a really good role model for all of our students,” he said. “Being a small school and trying to find an identity, we were really happy to have Jarod with that senior leadership, and his presence and his demeanor.”

Arroyo’s competitive swimming career has meant sacrifices for his family. He moved to the Valley from Utah in 2016 with his mother and sister to train with the Pitchforks Aquatics swim club and its head coach, Fernando Canales. But Arroyo’s father, a professor of physiology at Brigham Young University, stayed behind. His father is from Puerto Rico, which allowed Arroyo to join the national team at age 15.

“Someday, I think by achieving my goals, that will repay them because they’ll know it was worth it,” he said.

He credits his parents with encouraging him to take swimming lessons at age 4 — even though he was afraid of the water. By age 10, he knew swimming was for him.

“My parents made sure I played lots of different sports. I played basketball, baseball, soccer, tennis,” he said. “And when I was 10, they said, ‘You have to pick one’ so I chose swimming.”

This summer, Arroyo will compete in the Pan American games in Peru, where he could qualify for the 2020 Olympics, and possibly in the world championships in Korea. His specialty events are the 400- and 200-meter individual medley and the 200-meter butterfly.

“When I was 12, watching the Olympics would inspire me,” he said. “And when I watched them in 2016 was when I realized how close I was to qualifying."

Arroyo has idolized Michael Phelps, the swimming legend and most decorated Olympian of all time, with 28 medals, and was thrilled when he got to meet him.

“He’s really chill and laid back. I thought he would be so intense but he’s the nicest guy,” he said.

Phelps’ coach was Bob Bowman, who is now head coach of Sun Devil swimming and diving, which Arroyo will join in fall 2020.

“I’m so excited to come to ASU because not only do they have amazing facilities, but the men’s team has a really good culture of excellence and that’s thanks to Bob Bowman,” said Arroyo, who plans to double major in business and kinesiology because he wants to be a chiropractor.

But for the next several months, all his energy will be on getting to Tokyo for the 2020 Olympics.

“I like to visualize myself there,” he said. “That helps me to push through the hard practices toward the end goal.”

Stefanie Contreras, marketing and communications manager for ASU Prep, contributed to this story.

Mary Beth Faller

Reporter , ASU News