Vitamin D3 and vitamin K2 are two of the most-asked-about vitamins in our store, and they are often sold together for a good reason: they work as a team on calcium. Here's what each one does, how they complement each other, and what to look for on the label.
Vitamin D3 and K2 in detail
Vitamin D3 (cholecalciferol), the "sunshine vitamin," is the form your skin makes in sunlight. It helps your body absorb calcium from food and supports healthy immune function.* Many people fall short on vitamin D because of indoor lifestyles, sunscreen, age or the time of year.
Vitamin K2 is less famous but just as important. It activates proteins that help direct calcium into bones and teeth, and it supports normal blood clotting.*
How D3 and K2 complement each other
- Calcium absorption and use: D3 helps you absorb calcium; K2 helps put that calcium where it belongs, in bones and teeth.*
- Bone health: together they support healthy bone density as part of a balanced diet with enough calcium.*
- Cardiovascular wellness: K2 supports healthy arteries by helping keep calcium in the bones rather than soft tissue.*
- Immune support: vitamin D supports normal immune function.*
Food sources
Vitamin D3: mostly from sun exposure; also oily fish (salmon, mackerel, sardines), cod liver oil, egg yolks and fortified foods. Food alone usually supplies only a small share of what most adults need.
Vitamin K2: natto (fermented soybeans) is the richest source; smaller amounts come from cheese, egg yolks, grass-fed dairy and other fermented foods. K2 (menaquinone) stays in the bloodstream longer than K1 from leafy greens.
Is vitamin D3 the same as vitamin D2?
No. Vitamin D2 (ergocalciferol) is plant- or yeast-derived and often used in fortified foods. Vitamin D3 is the form your body makes from sunlight, and it is generally more effective at raising vitamin D levels in the blood. If you are vegan, look for D3 made from lichen.
How much vitamin D do you need?
The National Institutes of Health sets these Recommended Dietary Allowances:
- Infants (0–12 months): 400 IU (10 mcg)
- Children and adults up to 70: 600 IU (15 mcg)
- Adults over 70: 800 IU (20 mcg)
- Pregnant and breastfeeding women: 600 IU (15 mcg)
The upper limit for adults is 4,000 IU (100 mcg) a day unless your doctor advises more. Many people take 1,000–2,000 IU daily; a blood test from your doctor is the best way to know your own level.
For vitamin K, the National Academy of Medicine sets an Adequate Intake of 120 mcg a day for men and 90 mcg for women. D3 + K2 supplements commonly provide 45–200 mcg of K2 as MK-7.
When is the best time to take vitamin D3?
D3 is fat-soluble, so take it with a meal that contains some fat, such as eggs, avocado or nuts. Morning or midday works well for most people; a few find it affects their sleep if taken late in the evening. The best time is the one you'll remember every day.
Safety and considerations
- Too much vitamin D over time can raise calcium levels; stay within the label directions.
- Vitamin K affects blood clotting. If you take warfarin (Coumadin) or another blood thinner, talk to your doctor before taking any vitamin K.
- Vitamin D can interact with some medications, including certain diuretics and steroids. Check with your pharmacist or doctor.
Shop vitamin D3 and K2 in Palm Beach Gardens
We carry D3 drops, softgels, gummies and sprays, plus D3 + K2 combinations from Bluebonnet, Solaray, Carlson, NOW and more. Browse our vitamin D and vitamin K shelves online, or stop by the store at 2401 PGA Blvd, Suite 136 and ask us which one fits your routine.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for general information and is not medical advice.