Unlocking the Synergistic Benefits of Vitamins D and K for Cardiovascular Health

Vitamins D and K play crucial roles in maintaining bone health and regulating blood clotting in the body. Recent studies have revealed the synergistic effects of both vitamins on cardiovascular well-being. Low levels of vitamins K and D have been linked to a higher risk of all-cause mortality compared to individuals with normal levels of these vitamins. This article provides an overview of the benefits of vitamins K and D for heart health.

What Is Vitamin K?

Vitamin K is a fat-soluble vitamin found in various foods and also available as a dietary supplement. It is involved in the production of proteins responsible for blood clotting. Certain anticoagulant medications inhibit the action of vitamin K, preventing blood from clotting.

Vitamin K has two forms: K1 and K2. K1 is primarily found in leafy green vegetables and is the main dietary source of vitamin K. On the other hand, K2 is present in animal-based foods and fermented products like cheese and yogurt. Additionally, the bacteria in your gut produce some vitamin K2.

Research suggests that vitamin K may help prevent the calcification of blood vessel walls, making it beneficial for preventing atherosclerosis and supporting cardiovascular health. While the body stores vitamin K in the liver and other tissues like the brain, heart, and bones, it is not completely retained. About 50% is excreted through feces and 20% through urine, which is why a healthy diet often includes leafy greens. These vegetables are not only rich in vitamin K but also contain vitamins A, C, and E, iron, magnesium, potassium, calcium, carotenoids, antioxidants, and fiber.

What Is Vitamin D?

Vitamin D, also known as calciferol, is another fat-soluble vitamin present in certain foods, added to others like milk, and available as a dietary supplement. It is unique because the body can produce it when exposed to sunlight, earning it the nickname “sunshine vitamin.” Vitamin D promotes calcium absorption in the bones, preventing calcium accumulation in the blood. Insufficient vitamin D can lead to weak and brittle bones, as well as a condition called osteoporosis. In children, vitamin D prevents a condition known as rickets.

There are two primary forms of vitamin D: D2 and D3. The main active form in the body is Vitamin D2. Food sources of vitamin D include salmon, trout, tuna, fish oils, mushrooms, and egg yolks. Some foods are fortified with vitamin D, such as milk, margarine, cheese, ice cream, and plant-based milk alternatives from soy, almonds, or oats. Additionally, your body can produce its own vitamin D through exposure to sunlight, although factors like the time of day, cloud cover, smog, and skin melanin content affect the amount of sunlight absorbed. It’s important to protect yourself from excessive UV light exposure to prevent serious skin conditions, but it’s worth noting that sunscreen use inhibits the absorption of UV light required for vitamin D synthesis. This is why many foods are fortified with vitamin D, and why vitamin D supplementation is often recommended.

Cardiovascular Risk Factors

According to the World Health Organization (WHO), cardiovascular diseases have become the leading cause of global mortality, with an estimated 17.9 million deaths attributed to cardiovascular disease (CVD) in 2019. Cardiovascular diseases encompass conditions such as coronary heart disease (which leads to heart attacks), cerebrovascular disease (which leads to strokes), and peripheral arterial disease (which affects the blood vessels in the arms and legs). Heart attacks and strokes occur due to the blockage of blood flow to the heart or brain, typically caused by the buildup of fatty acids in the arterial walls. The good news is that most cardiovascular diseases can be prevented by making lifestyle modifications and addressing risk factors such as tobacco smoking, obesity, unhealthy diet, lack of physical activity, and excessive alcohol consumption.

One of the most impactful risk factors for cardiovascular disease prevention is adopting a healthy diet and quitting tobacco use. Reducing the consumption of processed foods high in salt, avoiding tobacco products, and limiting alcohol intake can significantly contribute to preventing cardiovascular diseases. Eating a diet rich in fruits and vegetables and engaging in regular physical activity for at least 30 minutes per day are two behaviors that can help safeguard against cardiovascular disease.

Synergistic Effects of Vitamins K and D

The Journal of Nutrition has highlighted the potential synergistic effects of vitamins D and K on cardiovascular health. Low concentrations of these vitamins have been associated with high blood pressure and increased arterial wall thickness. Vitamin D has been shown to stimulate the production of vitamin K-dependent proteins. While it is possible to supplement with vitamin D or vitamin K separately, taking them together may have a superior combined effect.

A study by Dal Canto et al., involving 601 individuals aged 70 and older, discovered that participants with low levels of both vitamin D and vitamin K had higher body mass indexes (BMIs), a greater prevalence of chronic conditions like type 2 diabetes, and higher blood pressure compared to those with normal vitamin levels. Furthermore, participants with low levels of vitamins D and K had a higher usage rate of heart disease medications. Among the 601 participants, 321 individuals with chronic conditions like high blood pressure exhibited structural changes in their heart muscles, and these individuals also had low levels of vitamins D and K.

In the VINDICATE study (Effects of Vitamin D on Cardiac Function in Patients with Chronic Heart Failure), high-dose supplementation with vitamin D (approximately 4,000 International Units [IU]) was associated with improved cardiac function, indicating better heart pumping ability. Women (but not men) with higher levels of vitamin K showed improvements in their left ventricular mass index, which measures the size and workload of the heart due to high blood pressure.

Recommended Intakes of Vitamins D and K

In addition to consuming leafy greens, many multivitamin supplements provide around 75% of the recommended daily value of vitamin K. Some dietary supplements exclusively contain vitamin K or combine it with other nutrients like calcium, magnesium, or vitamin D. The recommended daily intake of vitamin K is 120 micrograms (mcg) for men and 90 mcg for women. Before supplementing with vitamin K, it is advisable to consult with a healthcare provider, as it can interact with certain medications, particularly those used to prevent clotting.

To increase vitamin D intake, apart from consuming fish and milk or producing it through sun exposure, you can consider taking vitamin D supplements, either on their own or in combination with calcium. Vitamin D is measured in micrograms and International Units (IU), with 1 mcg equaling 40 IU. The recommended daily allowances for adults up to 70 years of age are 600 IU or 15 mcg, while individuals aged 70 or older are advised to have 800 IU daily. Several professional societies recommend higher intakes, with the Endocrine Society suggesting that adults take 1,500–2,000 IU daily.

Key Takeaway

Protecting cardiovascular health is essential for leading a long and healthy life. As mentioned by the World Health Organization, many risk factors associated with cardiovascular disease can be modified. Vitamin K and D can also contribute to safeguarding cardiovascular health. Before starting any new supplements, it is crucial to consult with a healthcare provider, especially if you are taking medications that may interact with dietary supplements. Remember that maintaining a healthy diet filled with leafy greens and vegetables can prevent severe cardiovascular conditions, allowing you to enjoy a long, healthy, and happy life.