Growing Evidence of Vitamin K Benefits for Heart Health

People who ate a diet high in vitamin K1 (found in leafy green vegetables) were 21 percent less likely to be hospitalised with cardiovascular disease related to atherosclerosis.

New Edith Cowan University (ECU) research has found that people who eat a diet rich in vitamin K have up to a 34 percent lower risk of atherosclerosis-related cardiovascular disease (conditions affecting the heart or blood vessels).

Researchers examined data from more than 50,000 people taking part in the Danish Diet, Cancer, and Health study over a 23-year period. They investigated whether people who ate more foods containing vitamin K had a lower risk of cardiovascular disease related to atherosclerosis (plaque build-up in the arteries).

There are two types of vitamin K found in foods we eat: vitamin K1 comes primarily from green leafy vegetables and vegetable oils while vitamin K2 is found in meat, eggs and fermented foods such as cheese.

The study found that people with the highest intakes of vitamin K1 were 21 percent less likely to be hospitalised with cardiovascular disease related to atherosclerosis.

For vitamin K2, the risk of being hospitalised was 14 percent lower.

This lower risk was seen for all types of heart disease related to atherosclerosis, particularly for peripheral artery disease at 34 percent.

ECU researcher and senior author on the study Dr Nicola Bondonno said the findings suggest that consuming more vitamin K may be important for protection against atherosclerosis and subsequent cardiovascular disease.

“Current dietary guidelines for the consumption of vitamin K are generally only based on the amount of vitamin K1 a person should consume to ensure that their blood can coagulate,” she said.

“However, there is growing evidence that intakes of vitamin K above the current guidelines can afford further protection against the development of other diseases, such as atherosclerosis.

“Although more research is needed to fully understand the process, we believe that vitamin K works by protecting against the calcium build-up in the major arteries of the body leading to vascular calcification.”

University of Western Australia researcher Dr Jamie Bellinge, the first author on the study, said the role of vitamin K in cardiovascular health and particularly in vascular calcification is an area of research offering promising hope for the future.

“Cardiovascular disease remains a leading cause of death in Australia and there’s still a limited understanding of the importance of different vitamins found in food and their effect on heart attacks, strokes and peripheral artery disease,” Dr Bellinge said.

“These findings shed light on the potentially important effect that vitamin K has on the killer disease and reinforces the importance of a healthy diet in preventing it.”

Next steps in the research

Dr Bondonno said that while databases on the vitamin K1 content of foods are very comprehensive, there is currently much less data on the vitamin K2 content of foods. Furthermore, there are 10 forms of vitamin K2 found in our diet and each of these may be absorbed and act differently within our bodies.

“The next phase of the research will involve developing and improving databases on the vitamin K2 content of foods.

“More research into the different dietary sources and effects of different types of vitamin K2 is a priority,” Dr Bondonno said.

Additionally, there is a need for an Australian database on the vitamin K content of Australian foods (e.g. vegemite and kangaroo).

To address this need, Dr Marc Sim, a collaborator on the study, has just finished developing an Australian database on the vitamin K content of foods which will be published soon.

The paper ‘Vitamin K intake and atherosclerotic cardiovascular disease in the Danish Diet Cancer and Health Study’ was published in the Journal of the American Heart Association.

Source: Edith Cowan University

Low Vitamin K Levels Linked to Mobility Limitation and Disability in Older Adults

Low levels of circulating vitamin K are linked to increased risk of mobility limitation and disability in older adults, identifying a new factor to consider for maintaining mobility and independence in older age, according to a study led by researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University.

The study, published online in the Journal of Gerontology: Medical Sciences, is the first to evaluate the association between biomarkers of vitamin K status and the onset of mobility limitation and disability in older adults.

“Because of our growing population of older people, it’s important for us to understand the variety of risk factors for mobility disability,” said Kyla Shea, first and corresponding author and a nutrition scientist in the Vitamin K Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts University.

“Low vitamin K status has been associated with the onset of chronic diseases that lead to disability, but the work to understand this connection is in its infancy. Here, we’re building on previous studies that found that low levels of circulating vitamin K are associated with slower gait speed and a higher risk of osteoarthritis,” she continued.

The new study examined two biomarkers: circulating levels of vitamin K (phylloquinone) and a functional measure of vitamin K (plasma ucMGP). Using participant data from the Health, Aging, and Body Composition Study (Health ABC), the study found that older adults with low levels of circulating vitamin K were more likely to develop mobility limitation and disability. The other biomarker, plasma ucMGP, did not show clear associations with mobility limitation and disability.

Specifically, older adults with low circulating vitamin K levels were nearly 1.5 times more likely to develop mobility limitation and nearly twice as likely to develop mobility disability compared to those with sufficient levels. This was true for both men and women.

“The connection we saw with low levels of circulating vitamin K further supports vitamin K’s association with mobility disability,” said senior author Sarah Booth, a vitamin K and nutrition researcher, and director of the HNRCA. “Although the two biomarkers we looked at are known to reflect vitamin K status, biomarker levels can also be affected by additional known or unknown factors. Further experiments to understand the mechanisms of biomarkers and vitamin K and their role in mobility are needed.”

The study used data from 635 men and 688 women ages 70-79 years old, approximately 40 percent of whom were black, who participated in Health ABC. In Health ABC, mobility was assessed every six months for six to ten years through annual clinic visits and phone interviews in the intervening time. For the present analysis, the researchers defined mobility limitation as two consecutive semi-annual reports of having any amount of difficulty either with walking a quarter of a mile or climbing 10 steps without resting, and mobility disability as two consecutive semi-annual reports of having a lot of difficulty or inability to walk or climb the same amount.

Circulating vitamin K levels reflect the amount of vitamin K in the diet. The best food sources of vitamin K include leafy greens such as spinach, kale and broccoli and some dairy products. For an average adult, one cup of raw spinach provides 145 micrograms (mcg) of vitamin K1, or 181 percent of the Daily Value; one cup of raw kale provides 113 mcg, or 141 percent; and half of a cup of chopped boiled broccoli provides 110 mcg, or 138 percent.

Source: Tufts University


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Eating More Vitamin K Found to Help, Not Harm, Patients on Warfarin

When prescribed the anticoagulant drug warfarin, many patients are told to limit foods rich in vitamin K, such as green vegetables. The results of a new clinical trial call that advice into question and suggest patients on warfarin actually benefit from increasing their vitamin K intake–as long as they keep their intake levels consistent.

Warfarin is widely used to prevent the dangerous blood clots that cause heart attacks and strokes. The drug’s dosage must be carefully calibrated to balance the risk of clots against the risk of uncontrolled bleeding. Because warfarin counteracts the activity of vitamin K in the blood, large swings in vitamin K intake can disrupt this balance.

The current recommendation to keep daily vitamin K intakes consistent often translates into patients limiting vitamin K intake. According to the new trial, patients would be better advised to increase the amount of vitamin K in their diet.

“I think all warfarin-treated patients would benefit from increasing their daily vitamin K intake, said lead study author Guylaine Ferland, professor of nutrition at Université de Montréal and scientist at the Montreal Heart Institute Research Centre. “That said, given the direct interaction between dietary vitamin K and the action of the drug, it is important that (higher) daily vitamin K intakes be as consistent as possible.”

Ferland will present the research at Nutrition 2019, the American Society for Nutrition annual meeting, held June 8-11, 2019 in Baltimore.

“Our hope is that healthcare professionals will stop advising warfarin-treated patients to avoid green vegetables,” said Ferland. She explained that eating plenty of green vegetables and other nutritious vitamin-K rich foods can help stabilize anticoagulation therapy and offers many other health benefits.

The study is the first randomized controlled trial to test how patients on warfarin respond to a dietary intervention aimed at systematically increasing vitamin K intake. Researchers enrolled 46 patients with a history of anticoagulation instability. Half attended dietary counseling sessions and cooking lessons that provided general nutrition information, while half attended counseling sessions and cooking lessons focused on increasing intake of green vegetables and vitamin-K rich oils and herbs.

After six months, 50 percent of those counseled to increase their vitamin K intake were maintaining stable anticoagulation levels, compared with just 20 percent of those who received the general nutritional counseling, a significant improvement. The results suggest patients taking warfarin would benefit from consuming foods that provide a minimum of 90 micrograms of vitamin K per day for women and 120 micrograms per day for men, Ferland said.

Source: American Society for Nutrition

Low Vitamin K May Reduce Mobility in Older Adults

Catharine Paddock wrote . . . . . . . . .

Dietary sources of vitamin K include kale, spinach, broccoli, and other leafy greens. Some dairy foods also contain vitamin K.

The investigators who carried out the study say that their findings “suggest vitamin K may be involved in the disablement process in older age.”

They describe their work in a paper that features in a recent issue of The Journals of Gerontology: Series A.

Previous studies have established links between vitamin K and long-term conditions that can raise the risk of mobility disability. These conditions include cardiovascular disease and osteoarthritis.

However, none of those earlier investigations had examined the relationship between vitamin K and mobility disability directly.

M. Kyla Shea is the new study’s first and corresponding author. She researches Vitamin K at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, MA.

Shea explains that: “Low vitamin K status has been associated with the onset of chronic diseases that lead to disability, but the work to understand this connection is in its infancy.”

She and her colleagues believe that they are the first to evaluate the relationship between “vitamin K status and incident mobility disability” in older adults.

The new evidence builds on earlier studies that have associated low levels of circulating vitamin K with “slower gait speed and a higher risk of osteoarthritis,” Shea explains.

Mobility is fundamental to healthy aging

Researchers typically define mobility as the “ability to move independently” from one place to another.

Physical independence is integral to healthy aging and older adults’ quality of life. From being able to get out of bed to walking and climbing stairs, much of daily activity involves mobility.

A 2018 study that reviewed the available evidence suggested that around 30% of older adults have limited mobility.

The most common causes of mobility disability in older people are the onset of lung problems, arthritis, and other long-term conditions.

A common measure of mobility is the ability to walk and climb stairs.

Mobility and vitamin K status

Vitamin K is a group of fat-soluble compounds that have a similar chemical structure and are present in some foods. Phylloquinone is the main dietary form of vitamin K and is present mainly in leafy greens.

To assess vitamin K status, Shea and her colleagues measured two blood biomarkers: phylloquinone and uncarboxylated matrix Gla protein (ucMGP), a protein that requires vitamin K. They note that ucMGP in the blood “increases when vitamin K status is low.”

The data that they analyzed came from 688 women and 635 men in the Health, Aging, and Body Composition (Health ABC) Study. Around 40% of the participants were black, and their ages ranged from 70 to 79 years.

The Health ABC study assessed mobility every 6 months for a period of between 6 and 10 years. The participants attended clinics and also completed interviews on the phone.

The researchers defined mobility limitation as two consecutive 6-monthly reports of experiencing “any amount of difficulty either with walking a quarter of a mile or climbing 10 steps without resting.”

They defined mobility disability as two consecutive 6-monthly reports of experiencing “a lot of difficulty or inability” to complete the same walking and climbing challenge.

The analysis showed that the older people who were most likely to develop mobility limitation and disability were the ones with low blood levels of phylloquinone.

In particular, the researchers found that developing mobility limitation was almost 1.5 times more likely in those with low blood levels of phylloquinone compared with those who had sufficient levels.

In addition, the chance of developing mobility disability for those low in phylloquinone was almost double that of those with sufficient levels.

There was no clear relationship between either mobility limitation or disability with blood levels of ucMGP.

The results for men and women were largely similar.

The researchers call for further studies to confirm their findings and clarify the mechanisms that might link vitamin K to mobility.

Source: Medical News Today

Leafy Greens May Contribute to A Healthy Heart

Ana Sandoiu wrote . . . . . .

A new study published in The Journal of Nutrition examines the link between vitamin K levels and heart structure and functioning in young people.

Vitamin K plays a key role in blood coagulation and bone health. Deficient levels of the vitamin raise the risk of hemorrhage, osteoporosis, and bone fractures.

In its dietary form, vitamin K is known as phylloquinone, or vitamin K-1. This is abundantly found in leafy green vegetables such as kale, parsley, broccoli, spinach, iceberg lettuce, and cabbage.

The new research suggests that insufficient levels of the vitamin may affect the structure of the heart, leading to a condition called left ventricular hypertrophy (LVH).

The left ventricle is the heart’s major pumping chamber, and in LVH, this chamber is enlarged to an unhealthy degree. As the authors of the new study explain, a larger heart can malfunction with time, becoming less effective at pumping blood.

LVH tends to affect adults, but the researchers decided to study this heart structure in young people because cardiac abnormalities that begin in childhood tend to predict the risk of cardiovascular disease in adulthood.

To the best of the authors’ knowledge, this is the first time that a study has examined links between vitamin K levels and heart structure in teenagers.

Mary K. Douthit and Mary Ellen Fain, both of the Georgia Prevention Institute at Augusta University, are the study’s co-first authors. Dr. Norman Pollock, a bone biologist at the same institute, is the study’s corresponding author.

Low vitamin K-1 intake correlates with LVH

Douthit and colleagues examined 766 healthy adolescents aged between 14 and 18. Half of the participants were male and half were female. Half of the participants were also black Americans.

The researchers assessed the diet and physical activity habits of these teenagers over a period of 7 days, using the participants’ self-reporting and accelerometry devices. Left ventricular structure and functioning were assessed using echocardiography.

Overall, the study found that the teenagers who consumed the least amount of vitamin K-1 had considerably greater left ventricles compared with those who consumed sufficient amounts of the vitamin.

Around 10 percent of the teenagers had LVH to some degree, as determined by measurements of the overall size of the ventricle and the thickness of its walls.

The researchers divided the results into tertiles, or thirds, of vitamin K-1 intake. They found, “The prevalence of [LVH] progressively decreased across tertiles of phylloquinone intake.”

In other words, the more vitamin K-1 the teenagers consumed, the less likely they were to develop LVH.

Fain says that the findings were independent of other potential confounders, such as sex, race, or physical activity patterns. The findings help them to “clarify the importance of phylloquinone intake to cardiovascular development,” the authors write.

Although further research is now needed, they add, the new findings could ultimately “lead to phylloquinone interventions in childhood aimed to improve cardiovascular development and to reduce the subsequent risk of [cardiovascular disease].”

Source: Medical News Today


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