Vitamin D3 & K2: A Secret Weapon for Weight Loss?

Vitamin D3 plays a vital role in several aspects of weight loss—metabolism, thyroid function, glucose metabolism, insulin sensitivity, and body fat regulation—but the role of vitamin D3 and K2 is directed more towards bone and heart health than weight loss.

Most people are familiar with the importance of vitamin D3 supplementation, but they’re unaware that vitamin K helps ensure proper transportation of vitamin D3.

Naturally, it’s a power duo that should always be taken together. But while the pair is great for bone health, does it offer benefits for weight loss?

If you’re struggling to lose weight, we’re giving you all the details on whether vitamin D3 and K2 can support weight loss.

Let’s start with the basics: what are vitamin D2 and K2, and what do they do?

The Benefits of Vitamin D3 and K2

Vitamin D3

Chances are you’ve heard something about vitamin D3. The sunshine vitamin has been all the rage lately for anyone looking to achieve optimal health from the inside out.

It’s called the sunshine vitamin because it’s produced in the body from exposure to UVB rays from the sun. But while vitamin D2 converts to the active form, vitamin D3 is the most beneficial supplementation form.

Also known as cholecalciferol, vitamin D3 is a fat-soluble vitamin produced endogenously that plays a crucial role in helping your body absorb calcium and phosphorus and, therefore, maintaining healthy bones.

But while vitamin D may be classified as a vitamin, it functions more as a fat-soluble hormone with endocrine, paracrine, and autocrine functions ¹.

You’ll find the vitamin D receptor in virtually all types of cells, indicating that its roles extend far beyond bone metabolism.

Some of these functions include:

• Immune function
• Mood
• Inflammation
• Weight management
• Cardiovascular health
• Growth and development
• Brain health
• GI disease prevention

Although relatively easy to obtain, most people are low in vitamin D, which can lead to a host of side effects, including:

• Weakened immunity/frequent illness or infection
• Fatigue and tiredness
• Bone pain
• Back pain
• Slow wound healing
• Bone loss (osteomalacia)
• Hair loss
• Muscle pain
• Weight gain
• Anxiety/depression

Vitamin K2

The other half of the power duo is vitamin K2, which refers to a group of fat-soluble compounds that play a major role in everything from blood clotting and bone health to cardiovascular health to insulin sensitivity ².

The primary role of vitamin K is as a cofactor for vitamin K-dependent proteins that require carboxylation for optimal activity.

But how is vitamin K involved?

Dietary vitamin K intake is a limiting factor in these carboxylation reactions ³; insufficient levels lead to partial carboxylation, which interferes with its actions.

Like other nutrients, there’s more than one form of vitamin K. Vitamin K1, also known as phylloquinone, is found primarily in plant-based foods and supplements. In contrast, vitamin K2 or menaquinone comes in several forms and is found in animal foods.

The primary menaquinones we look at are short-chain MK-4 and long-chain menaquinones MK-7, MK-8, MK-9, and MK-10, all of which can be obtained through diet.

To summarize, vitamin K is involved in ^4-9:

• Bone health
• Preventing vascular calcification (calcium buildup in the arteries)
• Enhancing cardiovascular health
• Insulin sensitivity
• Blood clotting
• Neuroprotection
• Neuroinflammation

For people that don’t consume animal products, getting enough vitamin K2 through diet can be tricky, so knowing the signs and symptoms of vitamin K deficiency can be helpful:

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• Easy bruising
• Small blood clots underneath the nails
• Bleeding in mucous membranes that line areas inside the body
• Dark black, tar-like stool that contains blood
• Weakened bones (increased risk of fractures)

Why Should Vitamin D Be Taken with Vitamin K2?

Knowing the optimal time to take vitamins and minerals can feel like a losing battle, but when it comes to vitamin D3 and K2, together is better. Research suggests that vitamin D3 and K2 have an important synergetic relationship.

These nutrients are required to ensure calcium transported by vitamin D is effectively absorbed into your bones instead of accumulating and depositing in blood vessel walls ¹⁰.

One of vitamin D’s leading roles is in maintaining normal calcium levels in the blood. It does this in two ways ^{11, 12}:

1. Supporting calcium absorption: Enhances the absorption of calcium from dietary intake.
2. Takes calcium from bones: When dietary calcium is insufficient, vitamin D pulls calcium from the bones to maintain adequate serum concentrations.

Insufficient calcium intake causes calcium to be pulled from bones, which, over time, can lead to bone loss and even osteoporosis. So, how does vitamin K fit into the picture?

Although vitamin K has its roles in supporting bone health—promoting the calcification of bone and reducing calcification of soft tissue—a high intake of vitamin D without sufficient vitamin K might spell trouble.

There are several lines to support this: ^13-19:

• Vitamin D toxicity can lead to hypercalcemia
• Calcified blood vessels increase the risk of cardiovascular issues
• Vitamin K deficiency is associated with blood vessel calcification
• High-dose vitamin K supplements in animal studies prevented blood vessel calcification and may reduce it in humans
• A higher vitamin K intake may reduce the risk of heart disease

Simply put, loading up on vitamin D without vitamin K can lead to blood vessel calcification.

But while many of the benefits of D3 and K2 extend cardiovascular and bone health, what’s the deal with weight?

Vitamin D3 and K2 for Weight Loss: Is There Evidence?

There’s a growing body of evidence showing that vitamin D3 and K2 can both promote healthy weight management.

There are a few essential roles for vitamin D in weight loss ^20-23:

1. Optimizes metabolism by supporting healthy thyroid function
2. Promotes proper glucose metabolism by stimulating insulin release from pancreatic B-cells
3. Assists with insulin resistance
4. May reduce fat cell formation and accumulation

While vitamin D3 may not directly boost your weight loss efforts, research suggests that vitamin D deficiency can lead to weight gain in that obese individuals tend to have lower vitamin D levels ²⁴.

Vitamin D receptors are also widely distributed on adipocytes, and vitamin D levels may influence lipogenesis, lipolysis, adipogenesis, and adipocyte gene transcription.

Several studies have shown links between higher vitamin D levels and greater fat and weight loss, as well as improved fat oxidation and total energy expenditure ^{25, 26}.

But what about vitamin K2?

The links between vitamin K2 and weight loss aren’t as concrete as with vitamin D3. Still, some research shows that a high intake of vitamin K2 may promote weight loss and abdominal and visceral fat loss in subjects with a strong increase in circulating carboxylated osteocalcin (cOC), which is used as a marker of vitamin K status ²⁷.

How Much Vitamin D3 and K2?

While vitamin D3 and K2 may not be the power duo for weight loss, they are the power duo for optimal health, so getting enough of them through diet and supplementation is crucial. But how much do you need?

The recommended intake for vitamin D3 is up to 100 mcg (4,000 IU) for adults over 19 and pregnant and breastfeeding teens and women.

For K2, the recommended intake for men over 19 is 120 mcg and for women is 90 mcg, including breastfeeding and lactating women.

Final Thoughts

Vitamin D3 and K2 both have a role in optimal performance and maintaining an optimal weight. Still, based on research, it’s not likely that they have any direct and profound contributions to weight loss.

That said, it’s still important to get enough. If you can’t do so by diet, supplementation is the next best thing—and for that, we recommend Performance lab D3+K2.

It’s an advanced D3+K2 complex using liposomal vitamin D for maximum absorption (86% more potent than other forms) and NutriGenesis® K2 for the most effective food-identical form.