Vitamin K is a vital fat-soluble nutrient essential for blood clotting and bone health, found predominantly in green leafy vegetables but also present in various fruits. Whilst vegetables remain the richest sources, certain fruits such as kiwi, avocado, blueberries, and prunes provide meaningful amounts of vitamin K1 (phylloquinone) and can help diversify your intake. Understanding which fruits contain vitamin K is particularly important for individuals managing anticoagulant therapy or seeking to support overall health through diet. This article explores vitamin K-rich fruits, daily requirements, and practical tips for incorporating them into a balanced UK diet.

What Is Vitamin K and Why Do You Need It?

Vitamin K is a fat-soluble vitamin essential for several critical physiological processes in the human body. It exists primarily in two forms: vitamin K1 (phylloquinone), found predominantly in green leafy vegetables and some fruits, and vitamin K2 (menaquinone), which is found in fermented foods and animal products. Bacteria in the gut can produce some vitamin K2, though the contribution to overall vitamin K status varies and is uncertain.

The most well-established function of vitamin K is its crucial role in blood clotting (coagulation). Vitamin K acts as a cofactor for enzymes that activate clotting factors in the liver, including factors II, VII, IX, and X. Without adequate vitamin K, the blood cannot clot properly, leading to increased bleeding risk and potentially serious haemorrhagic complications. This is why newborn babies in the UK are routinely offered vitamin K prophylaxis, usually as an intramuscular injection, to prevent Vitamin K Deficiency Bleeding (VKDB), as they are born with limited stores.

Beyond coagulation, vitamin K plays an important role in bone health. It activates proteins such as osteocalcin, which helps bind calcium to the bone matrix, thereby supporting bone mineralisation and strength. Some research suggests vitamin K may contribute to cardiovascular health by preventing calcium deposition in arterial walls, though evidence remains limited and inconclusive, and does not currently support supplementation for this purpose in the general population. Adequate vitamin K intake is important throughout life to support essential bodily functions and maintain overall health.

Which Fruits Are High in Vitamin K?

While green leafy vegetables are the richest dietary sources of vitamin K1, several fruits also provide meaningful amounts of this essential nutrient. Understanding which fruits contain vitamin K can help individuals diversify their intake, particularly those who may have difficulty consuming large quantities of vegetables or who are managing their vitamin K intake for medical reasons, such as patients taking warfarin.

Kiwi fruit stands out as one of the richest fruit sources of vitamin K, with a medium kiwi (approximately 80g) providing approximately 28–40 micrograms. Both green and gold varieties contain vitamin K, though green kiwis typically have slightly higher levels. Avocado is another excellent source, with half an avocado (approximately 70g) containing around 21 micrograms of vitamin K. It is worth noting that avocados are also rich in healthy monounsaturated fats, which can enhance the absorption of this fat-soluble vitamin.

Blueberries, blackberries, and grapes provide moderate amounts of vitamin K, with 100g of blueberries offering approximately 29 micrograms. Prunes (dried plums) are particularly noteworthy, containing about 60 micrograms per 100g serving, making them one of the most concentrated fruit sources. Other fruits with smaller but still relevant amounts include pomegranate, figs, and tomatoes (botanically a fruit), each contributing to daily vitamin K intake.

It is important to recognise that whilst these fruits contain vitamin K, the amounts are generally lower than those found in leafy greens such as kale, spinach, or spring greens. However, fruits offer additional nutritional benefits including fibre, antioxidants, and other vitamins, making them valuable components of a balanced diet. For individuals on warfarin, maintaining consistent fruit intake is more important than avoiding vitamin K-containing foods entirely. Do not start vitamin K supplements or make large, abrupt dietary changes without consulting your anticoagulation clinic.

Note that vitamin K content can vary by cultivar, ripeness and analytical method used to measure it.

How Much Vitamin K Do You Need Daily?

The UK does not have a formal Reference Nutrient Intake (RNI) for vitamin K due to limited data on requirements. Instead, the Department of Health and Social Care provides guidance on safe intake levels based on observed intakes in healthy populations.

For adults, the suggested safe intake is approximately 1 microgram per kilogram of body weight per day. This translates to roughly 70 micrograms daily for women and 80 micrograms daily for men of average weight. Pregnant and breastfeeding women do not require significantly increased amounts, as vitamin K does not readily cross the placenta or concentrate in breast milk, which is why newborns receive supplementation. Children's requirements are proportionally lower, ranging from approximately 10 micrograms for infants to 45–60 micrograms for adolescents.

Most people in the UK obtain sufficient vitamin K through a varied diet that includes vegetables, fruits, and other food sources. Deficiency is relatively uncommon in healthy adults with normal digestive function, as the body recycles vitamin K efficiently. However, certain groups are at higher risk of inadequacy, including:

• Newborn infants (hence routine supplementation)

• Individuals with malabsorption disorders (coeliac disease, Crohn's disease, ulcerative colitis)

• Those with chronic liver disease, where vitamin K-dependent clotting factor production is impaired

• People taking certain medications, including long-term antibiotics (which disrupt gut bacteria), bile acid sequestrants, orlistat, enzyme-inducing anticonvulsants (such as carbamazepine, phenytoin), and certain cephalosporin antibiotics

If you are taking warfarin or other vitamin K antagonist anticoagulants, it is essential to maintain consistent vitamin K intake rather than avoiding it entirely. Sudden changes in dietary vitamin K can affect anticoagulation control and INR (International Normalised Ratio) levels. Patients should discuss their diet with their GP or anticoagulation clinic and avoid drastic dietary changes without medical guidance. It's worth noting that direct oral anticoagulants (DOACs) such as apixaban and rivaroxaban are not affected by dietary vitamin K intake.

Tips for Including Vitamin K Fruits in Your Diet

Incorporating vitamin K-rich fruits into your daily diet is straightforward and can enhance both nutritional intake and meal variety. Because vitamin K is fat-soluble, consuming these fruits alongside a source of healthy fat can improve absorption and utilisation by the body.

Practical suggestions for increasing vitamin K fruit intake include:

• Start your day with kiwi fruit – Add sliced kiwi (80g, one medium fruit) to porridge, yoghurt, or smoothies for a vitamin K boost at breakfast. The fruit's natural sweetness complements both sweet and savoury dishes.

• Include avocado regularly – Use avocado in salads, on wholegrain toast, or blended into smoothies. Pair with olive oil-based dressings to enhance fat-soluble vitamin absorption.

• Snack on berries – Keep fresh or frozen blueberries and blackberries on hand for convenient snacking (a portion is about 80g), or add them to cereals and desserts.

• Choose prunes for bone health – A small serving of prunes (30g, about 3-4 prunes) provides both vitamin K and other nutrients beneficial for bone health. They work well as a mid-morning or afternoon snack.

• Add pomegranate seeds – Sprinkle pomegranate arils over salads, grain bowls, or yoghurt for added texture, flavour, and nutrients.

For individuals on anticoagulant therapy, consistency is key. Rather than avoiding vitamin K-containing fruits, aim to consume similar amounts each week. Keep a food diary if needed and inform your anticoagulation clinic of any significant dietary changes. Avoid starting vitamin K-containing supplements or concentrated green powders without consulting your clinic first. If you notice unusual bruising, bleeding gums, or blood in urine or stools, contact your GP promptly. For severe bleeding, head injury, or black/tarry stools, seek urgent medical help via NHS 111 or 999.

Storage and preparation tips: Vitamin K is relatively stable during cooking and storage, though prolonged exposure to light can cause some degradation. Store fruits properly away from direct light to maintain freshness and nutritional content. Frozen fruits retain their vitamin K content well and offer a convenient, year-round option.

A balanced approach that includes a variety of fruits, vegetables, whole grains, and healthy fats will naturally provide adequate vitamin K alongside other essential nutrients. If you have concerns about your vitamin K intake or status, particularly if you have a medical condition affecting absorption or are taking medications that interact with vitamin K, consult your GP or a registered dietitian for personalised advice.

If you experience any suspected side effects from medicines, report them via the MHRA Yellow Card scheme.

Frequently Asked Questions