Strong bones, healthy muscles and a well-functioning immune system are vital throughout life to help us stay active, independent and full of vim and vigour. Yet today’s diet and lifestyle can make it hard to get the nutrients the body needs to work at its best.
🕒 7 min read
Vitamin D has long been recognised for its role in helping the body absorb calcium to support healthy bones, teeth, muscles and immunity. Yet deficiency is common especially as we get older.
Vitamin K, which contributes to normal blood clotting and the maintenance of normal bones, is also gaining interest for its ability to work alongside vitamin D, guiding calcium to where it’s required. It too is often lacking in today’s diets.
Together they make perfect partners to help support long-term health and wellbeing.
Vitamin D3 supports normal bones, muscles and immune function, while vitamin K2 supports normal bones and blood clotting. MK-7 is a form of K2 used in supplements; the immune-support benefit comes from vitamin D.1
What is vitamin D3?
Vitamin D3 is one of two main forms of vitamin D used in supplements; the other is vitamin D2 (see below). It’s the form our bodies make when skin is exposed to sunlight. Because it matches the vitamin D our bodies naturally produce vitamin D3 is usually considered more effective at helping to improve vitamin D status.
Like all forms of vitamin D, vitamin D3 acts as a ‘pro-hormone.’ That is a chemical converted in the body into an active hormone - in this case calcitriol - needed to maintain:
- Normal blood calcium levels
- Normal bones and teeth
- Normal muscle function
- Immune system function
Vitamin D3 & K2
For immune, bone and blood health with vitamin D3 and vitamin K2 as MK-7.
- 100 µg vitamin D3 and 100 µg vitamin K2 per tablet
- Uses the pure, active form of K2 called MK-7
- Supports normal bones, muscles, immunity and blood clotting
What you need to know about vitamin D
It is fat soluble: stored in body fat
Sunlight is the main source: only a small amount comes from food; most is made in the skin through sunlight exposure
There are different forms:
- vitamin D2 - ergocalciferol - comes from plants including mushrooms, yeast, fortified foods and UV-exposed mushrooms
- vitamin D3 – cholecalciferol - is synthesised in the body when sunlight hits the skin; it’s also found in small amounts in foods such as oily fish e.g. salmon, mackerel and sardines, eggs, fortified spreads, and some breakfast cereals
- 25(OH)D – calcidiol - a circulating form of vitamin D measured via a blood test
Season and latitude play a part: in the UK and other northern regions most people can make enough vitamin D from sunlight from late March or early April to the end of September
It doesn't stick around: we do not make enough vitamin D from sunlight between October and early March in the UK2
Deficiency is common: one in six adults has low levels of vitamin D especially in winter and spring
Low levels aren’t always obvious: subclinical deficiency can occur without telltale symptoms and is linked with poorer bone health
Am I getting enough?
You may be at risk of low vitamin D if you:
- have black, brown or darker skin (the skin pigment melanin reduces UVB absorption)
- use a high strength sunscreen or cover up with clothing
- live in the UK or another northern latitude
- spend little time outside between 11 a.m. and 3 p.m.
- are overweight or obese (vitamin D is stored in fat so less is available for the body to use)
- eat few vitamin-containing foods
- are older – skin synthesis declines with age
- live in a nursing home
- have conditions affecting fat absorption (e.g. liver disease, cystic fibrosis, coeliac disease, Crohn’s or Colitis) or have had gastric bypass surgery
The NHS advises adults with little sun exposure or darker skin to consider 10 micrograms (400 IU) daily throughout the year. A higher dose may be advised for a diagnosed deficiency; the risk factors above do not automatically mean you need more. Explore our Vitamin D range to compare options.2
What is vitamin K2?
Vitamin K2 (menaquinone) is a key member of the vitamin K family which as a whole is a group of compounds that contribute to normal blood clotting and the maintenance of normal bones.
Vitamin K works by activating proteins that move calcium around the body to places where it is needed such as the bones. Vitamin K contributes to normal blood clotting and the maintenance of normal bones.1
What you need to know about vitamin K
It is fat soluble: it is absorbed with fat-rich foods and stored in the body’s fatty tissue
There are different forms:
- Vitamin K1 (phylloquinone) comes mainly from plants: leafy greens (spinach, kale), vegetable oils, berries, kiwi fruit, and prunes
- Vitamin K2 is found in gut bacteria, fermented foods including some cheeses and natto (a traditional Japanese food made from fermented soya beans)
Vitamin K2 makes up around 10–25% of vitamin K intake: vitamin K1 makes up the rest. The exact proportion can vary by region.
MK-7 (menaquinone-7) is one form of vitamin K2 used in supplements, including Healthspan’s D3 and K2 formula. It provides vitamin K’s recognised support for normal bones and blood clotting. You can also find MK-7 in our separate Vitamin K2 supplement.
Note: Do not take vitamin K supplements while taking warfarin without advice from your doctor or anticoagulation clinic.4
Why vitamin D3 and vitamin K2 are often taken together
Calcium levels in our bodies are kept within a tight range. This is essential to maintain the level of calcium needed to maintain normal bones and teeth while preventing calcium overload elsewhere.
The body operates a finely tuned system to achieve this balance with vitamins D3 and K2 playing complementary roles:
- Vitamin D3 increases the amount of calcium we absorb
- Vitamin K2 contributes to the maintenance of normal bones
If vitamin K2 is lacking, the proteins responsible for managing calcium distribution stay inactive. This in turn means that calcium absorbed through the action of vitamin D may be used less effectively where it is most needed.
Think of them as two nutrients with complementary jobs: D3 helps the body absorb calcium, while K2 supports proteins involved in normal bone maintenance.
Together they create a natural synergy to support bone strength and contribute to overall wellbeing.
What does the evidence mean for you?
Vitamin D’s roles in normal bones, muscles and immune function, and vitamin K’s roles in normal bones and blood clotting, are recognised health claims. These benefits do not mean a D3 and K2 supplement treats osteoporosis or prevents fractures or infections.1
The NHS advises that most people should be able to get enough vitamin K from a varied, balanced diet. Choosing a combined supplement is an option, rather than a requirement for everyone taking vitamin D.3
Could I benefit from a combined supplement?
A supplement containing D3 and K2 may be useful if you
- spend little time in sunlight e.g. you spend a lot of time indoors, live in a northern latitude, cover your skin for cultural or other reasons
- have a low vitamin D level naturally
- are older and spend little time outdoors
- are post-menopausal (women) – vitamin D deficiency is common (though under-reported) in this group
- already take vitamin D3 but want the convenience of combining two nutrients that support normal bones
- are looking for broad support for normal bones, muscles and immune function.
Why choose Healthspan’s formulation?
Healthspan’s new formulation combines two well-researched active forms of vitamin D and vitamin K:
- vitamin D3
- vitamin K2 as MK-7
Each tablet provides 100 micrograms of vitamin D3 (4,000 IU) and 100 micrograms of vitamin K2. The vitamin D amount is the NHS adult daily upper limit, rather than the usual 10-microgram daily guidance; there is no equivalent 100-microgram limit for K2.
The two nutrients have been chosen to support the body’s natural processing of calcium as follows:
- Vitamin D contributes to normal blood calcium levels and the maintenance of normal bones and teeth
- Vitamin D contributes to the maintenance of normal muscle function and the function of the immune system
- Vitamin K contributes to normal blood clotting and the maintenance of normal bones.
All Healthspan supplements are crafted from the purest ingredients and rigorously tested in the UK to meet the highest standards of quality and safety.
