Research reviewed by Gram found that 47 active duty service members reported too little vitamin K2 and vitamin D, and their body fat and K2 intake did not significantly change over one year. Exploratory protein tests linked K2 to inflammation and blood sugar control, but this small study cannot prove K2 prevents injuries or heart disease.
Research reviewed by Gram analysis looked at whether vitamin K2, a nutrient found in fermented foods like cheese and natto, could help active duty soldiers and airmen stay healthy and ready for duty. The study followed 47 service members, averaging 27 years old, for 12 months. Many of them had high blood pressure, and 45% had more body fat than military standards allow. Participants reported getting too little vitamin K2 and vitamin D from their diets. Over the year, their body fat and vitamin K2 intake did not change in a meaningful way, and they reported 10 noncombat injuries to muscles, joints, or bones. In exploratory blood protein tests, vitamin K2 was linked to inflammation, bone structure, and blood sugar control. Because the group was small and the tests were exploratory, these links are early clues rather than proof that vitamin K2 protects service members from injury or heart disease.
Key Statistics
A 2026 cohort study of 47 active duty U.S. Army and Air Force members found that participants reported insufficient dietary intake of vitamin K1 plus K2 and vitamin D at the start of the study.
In a 12-month study of 47 service members published in 2026, 45% met the criteria for stage I hypertension and 45% exceeded military body fat standards at baseline.
A 2026 study of 47 active duty service members reported 10 noncombat musculoskeletal injuries over 12 months, while body fat and vitamin K2 intake showed no significant change.
The Quick Take
- What they studied: Researchers wanted to know whether the amount of vitamin K2 in people’s diets is linked to bone health, blood sugar and heart risk, inflammation, and the chance of getting hurt, in military members whose fitness and readiness matter a great deal.
- Who participated: 47 active duty members of the U.S. Army and Air Force, enrolled between August 2023 and July 2024. Most were men, the group was racially and ethnically diverse, the average age was 27, and the average time in service was 6.5 years.
- Key finding: Participants reported too little vitamin K2 and vitamin D in their diets at the start. Over 12 months, their body fat and vitamin K2 intake did not change significantly, and they reported 10 noncombat injuries. Early protein tests suggested links between vitamin K2 and inflammation and blood sugar control, but these were exploratory results.
- What it means for you: The study does not prove that vitamin K2 supplements or foods will prevent injuries, lower body fat, or protect the heart. It does suggest that many people may not get enough vitamin K2 and vitamin D, so paying attention to fermented foods and leafy greens in your diet may be a reasonable step to discuss with a doctor or dietitian.
The Research Details
The researchers followed a group of active duty soldiers and airmen over one year. At the start and again at 12 months, each participant filled out questionnaires about their age, background, and eating habits, including how often they ate foods that are rich in vitamin K2. Trained staff also measured body composition, bone density, blood pressure and other heart and blood sugar markers, and collected blood samples.
Activity trackers worn on the wrist recorded physical activity and sleep throughout the study period. This allowed the team to see how movement and rest changed alongside diet and health measures, rather than relying only on what people remembered.
In addition to the main measurements, the team ran an exploratory analysis of proteins in participants’ blood. Proteins are the molecules that carry out most of the body’s work, so changes in them can hint at how the body responds to a nutrient. This part of the study was designed to generate ideas for future research rather than to test a specific hypothesis.
Following the same people over time makes it easier to see whether changes in diet are connected to changes in health, because each person is compared with themselves. Collecting diet, body measures, activity, sleep, and blood samples together also gives a fuller picture than any single test could. Because military members have demanding physical jobs, studying them can reveal practical health challenges that matter for readiness.
This is a small study with 47 participants, which makes it hard to draw firm conclusions or apply the results to the general population. Diet was measured with questionnaires, which depend on memory and can be inaccurate. The protein analysis was exploratory, meaning it was not designed to confirm a specific result, so its findings should be treated as starting points. The study was published in a nursing journal, and its authors are nursing researchers, which reflects a focus on patient education and clinical practice.
What the Results Show
At the start of the study, participants reported that their diets did not provide enough vitamin K2 or vitamin D. Vitamin K2 is a nutrient that helps activate certain proteins that the body uses to keep bones strong and to manage inflammation, which is the body’s response to injury or irritation. Because these proteins depend on vitamin K2, low intake could matter for both bone and immune health.
Over the 12 months, participants reported only a slight increase in eating fermented foods, such as yogurt, cheese, and kimchi, which are among the richer everyday sources of vitamin K2. Their physical activity and sleep patterns did not change much over the year. Despite this, the researchers did not find a significant change in body composition, body fat, or intake of vitamin D or vitamin K2.
Participants also reported 10 noncombat musculoskeletal injuries during the study, which means injuries to muscles, bones, joints, or connective tissue that were not caused by combat. The study was not designed to determine whether vitamin K2 affected these injuries, so this number describes the group rather than showing a link to diet.
In the exploratory protein analysis, the researchers identified connections between vitamin K2 and proteins involved in inflammation, bone structure, the way the body handles blood sugar, and insulin receptors, which are the docking points that help cells respond to insulin. These links are interesting, but they come from a small, exploratory analysis and do not show cause and effect.
Nearly half of participants (45%) met the criteria for stage I hypertension, which means their blood pressure was higher than recommended, and 45% had body fat above military standards. These are important readiness concerns, and they show that heart and weight-related risks are common in this group even among young, active people. The study suggests that these are areas where nutrition and clinical support could be useful, though this study did not show that vitamin K2 changed them.
Earlier laboratory and animal studies have shown that vitamin K-dependent proteins help control bone building and inflammation, which is the basis for this research. Some large human studies have linked higher vitamin K2 intake with better bone and heart outcomes, mainly in older adults. This study adds information about a younger, active military population, a group that has been studied less often for vitamin K2, but it does not yet show the same benefits.
The study included only 47 people, so the results may not apply to other groups, such as women, older adults, or civilians. The study tracked people for only one year, which is too short to show long-term effects on injuries, heart disease, or diabetes. Diet was measured with questionnaires, which can be inaccurate. Injuries were self-reported rather than checked by medical records. The protein analysis was exploratory, and the study was not designed to prove that vitamin K2 causes any of the changes it observed. Without a comparison group receiving a vitamin K2 intervention, it is not possible to tell whether any changes came from diet or from other factors.
The Bottom Line
Based on this study alone, the evidence is not strong enough to recommend vitamin K2 supplements for preventing injuries, lowering body fat, or improving heart health (low confidence). The study does support paying attention to vitamin K2 and vitamin D intake, since participants were not getting enough of either (moderate confidence that the diet gap exists in this group). Eating more fermented foods and leafy greens is a low-risk step that many people can take, and a doctor or dietitian can advise whether a supplement is appropriate.
Service members, military health staff, nurses, and dietitians working with active duty personnel may find these findings useful for thinking about nutrition and readiness. Members of the general public who are interested in bone and heart health may also find the discussion helpful. People with kidney disease or who take blood thinners such as warfarin should talk to a doctor before taking any vitamin K supplement, because vitamin K can interact with certain medicines and conditions.
Changes in diet and nutrient levels can show up in blood tests within weeks, but changes in bone density, body fat, or injury rates usually take months to years to appear. This study only followed participants for 12 months and did not find a meaningful change in body fat or vitamin K2 intake, so it cannot tell us how long a benefit might take. Larger, longer studies would be needed to answer that question.
Frequently Asked Questions
Does vitamin K2 help prevent injuries in military members?
A 2026 study of 47 active duty Army and Air Force members did not test whether vitamin K2 prevents injuries. It recorded 10 noncombat musculoskeletal injuries over 12 months, and the researchers say more and larger studies are needed before any injury benefit can be claimed.
What foods are high in vitamin K2?
Fermented foods are among the richest everyday sources of vitamin K2, including natto, aged cheeses, sauerkraut, kimchi, and some yogurts. Participants in a 2026 study of 47 service members reported eating only slightly more fermented foods over one year.
Can vitamin K2 lower body fat or blood pressure?
A 12-month study of 47 active duty service members did not find a significant change in body fat tied to vitamin K2 intake. Although 45% had stage I hypertension and 45% exceeded military body fat standards at the start, the study did not show that vitamin K2 changed either.
Should I take a vitamin K2 supplement?
A small 2026 study suggests many service members may get too little vitamin K2 and vitamin D from food, but it does not prove supplements improve health. People taking blood thinners or with kidney disease should talk to a doctor first, since vitamin K can interact with some medicines.
Want to Apply This Research?
- Log the number of servings per week of fermented foods such as yogurt, aged cheese, sauerkraut, kimchi, or natto, and track your estimated daily intake of vitamin K2 and vitamin D using a food database. Aim to record at least 5 days per week so you can see trends over a month.
- Add one serving of a fermented food to a meal you already eat, such as yogurt at breakfast or sauerkraut with lunch, and keep a weekly leafy green side dish on your plan. Review your progress with the app’s weekly summary and discuss any vitamin supplement decision with your healthcare provider.
- Track fermented food servings, diet quality, blood pressure readings if you have a home monitor, body weight or waist measurements, and activity and sleep data from your wearable every month. Review trends every 3 months with a healthcare provider, and keep a log of any muscle, joint, or bone injuries so they can be discussed at a medical visit.
This article summarizes an early, small study of 47 active duty service members followed for 12 months. The findings are exploratory and cannot show that vitamin K2 prevents injuries, lowers body fat, or protects the heart. This information is for general education and is not medical advice. Talk with a doctor, registered dietitian, or military health provider before starting any supplement, especially if you take blood thinners or have kidney, heart, or bone conditions.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.