Osta K2 & D3 Algae by Vitakruid

Best absorbable forms of vitamin D & K

Vitamin D is a fat-soluble vitamin. Technically, vitamin D is not a vitamin but a hormone that the body can produce itself. Our skin captures sunlight and converts it into vitamin D. The form obtained from animal products (vitamin D3) is identical to the vitamin D produced by human skin, making it the best absorbable form for the human digestive system.

Vitamin K2 (MK-7)

Vitamin K2, also known as menaquinone, is produced by bacteria. There are many forms of menaquinone (MK), ranging from MK-4 to MK-14. It occurs in small amounts in dairy, meat, and eggs, and in moderate amounts in fermented foods such as yogurt and cheese. Japanese natto, fermented soybeans using Bacillus subtilis, is an exceptionally rich source of MK-7. For this reason, our product contains vitamin K2 in the best available form: menaquinone-7.

The importance of calcium and vitamin D during menopause

Calcium and vitamin D can help reduce bone mineral loss in women aged 50 and older during menopause. Low bone mineral density is a risk factor for fractures related to osteoporosis. This beneficial effect can be achieved with a daily intake of at least 1200 mg calcium from food sources such as milk, wholegrain bread, and spinach, combined with 20 mcg vitamin D from all sources.

For supplements, this effect is already achieved with 400 mg calcium, equivalent to two tablets of Osta K2 & D3.

Vitamin D3 increases calcium absorption in bones

Vitamin D3 offers many health benefits. It promotes calcium absorption, supports cell differentiation, contributes to muscle function, supports the immune system, and helps maintain strong bones and teeth. Vitamin D is therefore essential for a healthy calcium balance.

However, when high-dose vitamin D supplementation is used (from 75 mcg and higher), excessive calcium absorption may occur without proper regulation of where calcium is deposited. This may lead to unwanted calcium accumulation in kidneys and blood vessels.

Vitamin K2 supports bone formation

This is where vitamin K2 becomes important. Vitamin K2 contributes to bone composition and helps direct absorbed calcium to functional destinations such as bones and teeth.

Supplementation combining vitamin D3 and K2 is particularly relevant in colder climates where sunlight exposure is limited for much of the year, reducing natural vitamin D production. Additionally, Western diets often contain insufficient vitamin K2 for optimal health.

Vitamin D contributes to healthy bones and teeth

Our Osta K2 & D3 Algae product supports overall bone and dental health. Based on Lithothamnium calcareum (red algae), this formula includes vitamins D3 and K2 along with additional high-quality nutrients.

Aquamin®, a trademarked ingredient derived from red algae, provides highly bioavailable calcium, magnesium, strontium, and 72 trace minerals. This balanced nutrient mix supports bone formation and helps maintain strong bones. In 2016, Aquamin® received the Ingredient of the Year Award in the Healthy Ageing category.

Aquamin® red algae: nutrients from a natural source

Aquamin® is supplied by Marigot Ltd, a company specializing in sustainable algae harvesting. The red algae originate from the seabed off the west coast of Ireland and northwest coast of Iceland, regions known for exceptionally clean and mineral-rich waters.

Benefits

• Aquamin® red algae as a source of calcium and magnesium.
• Vitamin K2 supplied as extensively tested and award-winning MenaQ7®.
• Vitamin D3 and K2 (MenaQ7®) work synergistically.
• Aquamin® harvested off the west coast of Ireland and Iceland.
• Red algae naturally provide calcium and over 70 trace minerals.
• Magnesium supplied as highly absorbable magnesium bisglycinate.
• Produced in the Netherlands under strict quality standards.

Need advice?

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Patented ingredients

Aquamin® is a registered trademark of Marigot Ltd.

MenaQ7® Vitamin K2 is a trademark of NattoPharma ASA

Other information

Dietary supplement Vitamin supplement

Produced by Vitakruid BV
Jacobusspijkerdreef 430
2132 PZ Hoofddorp

For Smeets & Graas
G. Meirstraat 11
9728 TB Groningen
050 850 36 88

Last page change
8 februari 2026