4 Supplements to Take With Vitamin D for Better Absorption

Vitamin D helps your body absorb calcium, supports muscle movement, and boosts immune function. Many people take vitamin D supplements when they can’t get enough from fortified foods or sun exposure.

Here are four supplements that may enhance vitamin D absorption and provide added health benefits.

1. Magnesium

Magnesium is an important mineral for blood pressure regulation and nerve function. Taking magnesium with vitamin D supplements can increase vitamin D levels in the blood.

“Magnesium plays a crucial role in activating vitamin D in the body. If the body is deficient, vitamin D can remain in its inactive form,” Angel Planells, MS, RDN, a Seattle-based registered dietitian nutritionist and spokesperson for the Academy of Nutrition and Dietetics, told Verywell in an email.

Vitamin D helps prevent osteoporosis, a condition in which bones become weak and fracture-prone. Research suggests that vitamin D needs magnesium to support bone health and lower osteoporosis risk.

Because high doses of vitamin D can lower magnesium levels, talk with a healthcare provider about the right balance for your needs.

2. Omega-3 Fatty Acids 

You can find combination supplements that include vitamin D and omega-3 fatty acids.

“Because vitamin D is fat-soluble, taking it with omega-3s or other healthy fats can improve absorption,” Planells said.

Some research suggests that taking these supplements together may help slow biological aging and improve fasting blood glucose levels in people with prediabetes.

Omega-3 supplements such as fish, krill, and flaxseed oil are generally safe, but these may cause mild side effects like diarrhea or fishy burps.

3. Vitamin K2

Vitamin K2, a compound known as menaquinone, supports bone and heart health. Taking K2 with vitamin D may boost these benefits.

“Vitamin K2 works synergistically with vitamin D by helping direct calcium into bones and teeth rather than soft tissues or arteries,” Planells said.

Studies show that combining vitamins D and K2 may increase bone mineral density and reduce the risk of fractures and osteoporosis.

4. Probiotics

Researchers are still learning about the connection between vitamin D and gut health. Some studies show that vitamin D promotes good gut bacteria and may reduce intestinal inflammation in people with ulcerative colitis. A 2020 review also found that taking probiotics with vitamin D may improve mental health, insulin sensitivity, and inflammation.

Gut health may also influence how the body metabolizes vitamin D. Certain strains of gut-supporting probiotics could enhance vitamin D’s effects, but more research is needed, Planells said.

Take Vitamin D Supplements With Food

Whether you take vitamin D alone or with other supplements, it is a good idea to take it with a meal.

“Taking it on an empty stomach or without a fat source can reduce absorption substantially,” Planells said.

Vitamin D is fat-soluble, so it needs a fat source for absorption. Otherwise, you may feel nauseous or not get all the expected benefits.

Supplements to Avoid Taking With Vitamin D

While vitamin D supplements are generally safe, avoid taking them with certain medications, like orlistat, statins, steroids, and thiazide diuretics.

Vitamin D and calcium work together to support bone health, but taking them in high doses can cause nausea, vomiting, dehydration, or kidney stones. Check with your healthcare provider before combining them.

Planells added that vitamin D may also compete with the retinol form of vitamin A for receptor sites, and taking it with iron can reduce iron absorption.