What to take with vitamin D

In this article:

• Supplements to take with vitamin D
• Magnesium
• Vitamin K2
• Calcium
• Vitamin D absorption
• What to avoid on vitamin D

In this article

• Supplements to take with vitamin D
• Magnesium
• Vitamin K2
• Calcium
• Vitamin D absorption
• What to avoid on vitamin D

About 5% of people age 1 and older in the U.S. are at risk of a vitamin D deficiency, and another 18% are at risk of inadequate levels of vitamin D, according to national survey data from the National Institutes of Health (NIH): Office of Dietary Supplements. Some experts believe the number of people with a vitamin D deficiency to be much higher.

Low vitamin D can cause symptoms like fatigue and vague bone or muscle aches. Over time, deficiency can soften or weaken bones, causing rickets (a bone disorder) in children, osteomalacia in adults, and contributing to the bone loss in osteoporosis (a bone disease).

Because of this, healthcare providers often recommend vitamin D supplements for older adults, those with limited sun exposure or darker skin, anyone with an absorption issue like celiac disease or Crohn’s disease, and people with obesity (since vitamin D gets stored in body fat, leaving less in your blood). Most over-the-counter vitamin D3 (cholecalciferol) supplements are measured in international units (IU), with 1,000 to 2,000 IU a common starting point. It’s recommended to take vitamin D supplements with a fatty meal to improve absorption.

What supplements should I take with Vitamin D?

If you’re wondering what to take with vitamin D, taking it with a meal or snack that contains fat can improve absorption. However, vitamin D supplements are often combined with other nutrients or supplements, such as magnesium, calcium, and vitamin K2.

 

List of supplements to take with vitamin D
Nutrient or supplement	Why it pairs well with vitamin D	Notes on timing or form	Coupons
Magnesium	Helps to convert vitamin D from its inactive form into its usable form	Glycinate or citrate absorb better than oxide; 200 mg to 400 mg, often taken at night	Magnesium glycinate coupons Magnesium citrate coupons
Vitamin K2	Directs the calcium vitamin D helps absorb into bones rather than soft tissue	Fat-soluble, so take with a fatty meal; you can purchase combined D3 + K2 supplements	VItamin K2 coupons
Calcium	Vitamin D’s main role is helping your body absorb calcium for bone health	Calcium doses of 500 mg or less absorb best; calcium carbonate is best taken with food, while calcium citrate can be taken with or without food	Calcium coupons
Dietary fat	Vitamin D is fat-soluble, so fat in the gut improves how much you absorb	Take your supplement with a meal that contains some fat or with an omega-3 supplement	Omega-3 fish oil coupons

Vitamin D and magnesium

Magnesium and vitamin D work better together than they do alone, so they’re often taken at the same time. Vitamin D enters your body in its inactive form. Magnesium turns it into its active, hormone-like form, so your body can actually use it. When your body doesn’t have enough magnesium, vitamin D can’t do its job as well.

Nearly half of Americans don’t get enough magnesium through diet, according to NIH data. Early signs of low magnesium include loss of appetite, nausea, fatigue, and weakness. Severe magnesium deficiencies can cause muscle cramps and an abnormal heart rhythm. Because many people with low magnesium levels also have low vitamin D, symptoms of deficiencies in both can cause overlapping symptoms.

Magnesium glycinate, usually 200 mg to 400 mg taken at night, is well absorbed and has a calming effect for some people, says James J. Chao, MD, chief medical officer at VedaNu Wellness in San Diego, California.. He adds that magnesium oxide, which is common in lower-cost supplements, doesn’t absorb nearly as well, so the body may absorb less magnesium from a similar dose.

Food sources of magnesium include:

• Leafy greens, such as a kale and spinach
• Nuts, like almonds and cashews
• Seeds, such as pumpkin and chia seeds
• Legumes, such as beans and lentils
• Whole grains

Some people take vitamin D and magnesium to support weight loss, but there’s no solid evidence that this combination helps you lose weight. Correcting a deficiency may help you feel better overall, but neither nutrient is a weight-loss treatment.

RELATED: Which magnesium supplement is right for me?

Vitamin D and K2

Vitamin D and vitamin K2 work together to help your body use calcium. Vitamin D’s main job is to help your gut absorb calcium from the food you eat or from supplements. Vitamin K2 then activates special proteins (including osteocalcin and matrix Gla protein) that move that calcium into your bones.

Dr. Chao emphasizes that vitamin K2 is an important companion to vitamin D because it helps your body use calcium more effectively and keeps it from building up in soft tissue. However, according to the NIH, roughly two-thirds of Americans don’t get the recommended amount of vitamin K.

“Some research suggests that combining [vitamins] D3 and K2 may have some benefits for bone mineral density,” says Katie Whitson, MS, RDN, a registered dietitian nutritionist at Health Loft. “This works by K2 activating proteins that direct calcium to the bone while vitamin D increases calcium absorption.”

You can still absorb calcium without enough vitamin K2, but your body has less control over where that calcium ends up. Severe vitamin K deficiency is rare but can cause easy bleeding or bruising.

Many over-the-counter supplements combine D3 and K2 in a single capsule or tablet. If you’re considering one, ask your healthcare provider what dose is best.

Like the vitamin D and magnesium combo, D3 and K2 are sometimes marketed for weight loss, but there’s no strong evidence to support this.

Vitamin D and calcium

Vitamin D helps your gut absorb calcium from food, so without enough vitamin D, your body may absorb less of the calcium you eat. National survey data show that around 39% of people ages 4 and older don’t consume the estimated average calcium requirement, even with supplements. Severely low calcium levels can lead to numbness or tingling around the mouth or in the hands and feet, and in more serious cases, muscle spasms.

Pairing vitamin D and calcium makes the most sense if your diet is low in calcium or you’re already taking a calcium supplement for bone health. You can get too much of a good thing with these supplements. High intakes of calcium supplements, especially those that are combined with vitamin D, have been linked to a higher risk of kidney stones. Extremely high doses of vitamin D over long periods can also cause vitamin D toxicity. If you take a multivitamin, make sure you’re not double-dosing these supplements.

For kids, check with a pediatrician to decide whether a supplement is needed, and the appropriate dose. For adults, calcium absorbs best in doses of 500 mg or less at a time. Experts recommend getting as much of your calcium as possible from calcium‑rich foods, such as:

• Dairy, including milk, yogurt, and cheese
• Canned fish with bones, such as sardines
• Leafy greens

The best time to take vitamin D and calcium is with a meal. However, it’s best to avoid taking calcium supplements with iron-rich foods or supplements since calcium may interfere with iron absorption temporarily.

What helps your body absorb vitamin D?

Vitamin D is a fat-soluble vitamin, which means it absorbs best alongside dietary fat. “I usually tell clients to take vitamin D with a meal that has fats in it since it can help increase absorption,” says Whitson. Good pairings include eggs, avocado, nuts, olive oil, or fatty fish.

Whitson recommends vitamin D3 (cholecalciferol) over vitamin D2 (ergocalciferol) “since it is already in the form that the body creates from our skin, making it better at raising and maintaining vitamin D levels.” D2, found in plants and fungi, is also effective but it generally doesn’t raise vitamin D levels as well as D3.

Food sources of vitamin D include:

• Fatty fish including salmon, tuna, mackerel, and sardines
• Egg yolks
• Beef liver
• Cod liver oil
• Mushrooms

If you normally eat a low-fat diet, consider pairing your vitamin D with a meal with health fats or an omega-3 fatty acid supplement to help improve absorption.

Some fortified foods have added vitamin D to help you meet your daily needs, including:

• Milk
• Yogurt
• Orange juice
• Breakfast cereals
• Oat milk and other plant milks
• Infant formula

In some cases, your healthcare provider may check your vitamin D level through a blood test that measures 25-hydroxyvitamin D.

What not to take with vitamin D

Most supplements are safe to take with vitamin D, but a handful of medications can interfere with it or with the calcium it helps absorb:

• Xenical (orlistat), a weight-loss drug that blocks fat absorption, may prevent vitamin D absorption.
• Corticosteroids like prednisone may impair how your body absorbs vitamin D and calcium.
• Bile acid sequestrants like cholestyramine and colestipol can reduce vitamin D absorption.
• Anticonvulsants like phenytoin and phenobarbital may increase the breakdown of vitamin D.
• Thiazide diuretics combined with vitamin D may increase blood calcium levels.

You may not have to stop taking your vitamin D supplement, but your healthcare provider may recommend spacing doses or monitoring specific blood levels.

If you’re unsure, your pharmacist can review your full medication and supplement list for potential interactions.