Magnesium can help boost vitamin D levels. Here are foods that are rich in these minerals.

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Avocados are one food considered to be high in magnesium. Getty Images

If you’re looking to get more vitamin D in your diet, take it with a side of magnesium.

That mineral appears to help regulate levels of vitamin D, which in turn manages the levels of other minerals such as calcium and phosphorus. It also improves bone strength and possibly reduces the risk of cardiovascular disease and cancer.

Researchers at the Vanderbilt-Ingram Cancer Center in Tennessee say that magnesium raises levels of vitamin D in people who need more of that substance and lowers levels among those who have an excess amount of the vitamin in their system.

The researchers reached their conclusions after conducting a randomized clinical trial involving 250 people considered at risk of colorectal cancer.

The study, published in the December 2018 issue of the , was the first direct evidence that magnesium plays a role in vitamin D regulation.

A previous study from the same group of researchers found an association between low magnesium levels and low vitamin D levels.

Researchers also have noted variations in vitamin D synthesis, with some people failing to raise their levels of the vitamin even when taking high-dose supplements.

Dr. Qi Dai, the lead author on the latest study and a professor of medicine at Vanderbilt University Medical Center, said their research explains why.

“Magnesium deficiency shuts down the vitamin D synthesis and metabolism pathway,” Dai said.

Exposure to sunlight is the primary way to get vitamin D.

However, deficiency of the vitamin is common, especially in the northern United States and Canada.

About 40 percent of people in the United States and of people worldwide may be deficient in vitamin D.

Foods rich in vitamin D include salmon and other fatty fish, egg yolks, mushrooms, and milk and juice fortified with the vitamin.

“Vitamin D insufficiency is something that has been recognized as a potential health problem on a fairly large scale in the U.S.,” said Martha Shrubsole, PhD, a study co-author and a research professor of medicine at Vanderbilt University Medical Center. “A lot of people have received recommendations from their healthcare providers to take vitamin D supplements to increase their levels based upon their blood tests.”

“In addition to vitamin D, however, magnesium deficiency is an under-recognized issue,” she told Healthline. “Up to 80 percent of people do not consume enough magnesium in a day to meet the recommended dietary allowance.”

“We know magnesium plays many vital roles in the body and is a mineral that is essential to many many cellular functions. It has a clear role in helping with heart health, blood pressure, migraine treatment, and more,” said Dr. Arielle Levitan, co-founder of Vous Vitamin and co-author of “The Vitamin Solution: Two Doctors Clear the Confusion About Vitamins and Your Health.” “It is not surprising that one of its many functions is to facilitate vitamin D’s activities.”

“This has big implications for bone health, suggesting that taking a magnesium supplement may help people get to a desired level of vitamin D faster,” Levitan told Healthline. “Magnesium may also facilitate the actions of vitamin D on bone health, though the data to prove an actual benefit in regards to fractures is not clearly established.”

Dai said further research is needed to determine the molecular mechanism underlying magnesium’s effect on vitamin D synthesis.

Dark leafy greens, beans, whole grains, dark chocolate, fatty fish (salmon, for example), nuts, bananas, and avocados are among the foods rich in magnesium.

Dai told Healthline that the study proposes a novel system for getting individuals to the levels of magnesium needed for proper vitamin D utilization.

“First, measure individuals’ baseline intakes of magnesium and calcium; estimate ratio of calcium to magnesium from diet and supplementation; and provide personalized doses of magnesium supplementation to reduce calcium to magnesium ratio from above 2.6 to around 2.3,” he explained. “The average calcium to magnesium ratio is about 3.5 in the U.S. population.”

“Our previous studies conducted in populations with high or low calcium to magnesium ratios found calcium to magnesium ratios between 1.7 and 2.6 were optimal for calcium or magnesium to be beneficial to total mortality, or mortality due to cancer and cardiovascular disease,” he added.

“An additional 200 mg or so of magnesium will safely bring most people up to an adequate intake,” Rachel Fine, a registered dietitian and owner of To The Pointe Nutrition, a nutrition counseling firm in New York City, told Healthline.

A single avocado contains 58 mg of magnesium, for example. A slice of whole wheat bread contains 23 mg of magnesium.

“If a person is regularly choosing refined grains over whole grains, they could be coming up short in magnesium, which can also be impacting their vitamin D levels,” Summer Yule, a registered dietitian, told Healthline. “Refined flour is only enriched with vitamins B1, B2, B3, B9, and iron. The magnesium, vitamin B6, and fiber that are lost in the process of refining whole grains are not added back.”

Laura Kunces, PhD, RD, director of nutrition research at Thorne Research, told Healthline that given the widespread deficiencies in both vitamin D and magnesium, the findings may support wider use of supplements for both.

“This study found that low magnesium may reduce vitamin D levels in persons within a normal range,” she said. “This is an important connection because we continue to see a high prevalence of suboptimal blood levels of both vitamin D and magnesium for many reasons: location, age, weight, diet, genetics, etc.”

“This study also looked at people who were not clinically magnesium deficient, and found that even in these individuals, supplementation with magnesium helped to reverse resistant vitamin D deficiency,” Kunces added. “Even with all the increased awareness of the importance of vitamin D, we still see many Americans present in a low range… sometimes even when they are taking vitamin D.”

Magnesium can be important in regulating levels of vitamin D.

Many Americans fail to get enough magnesium as well as vitamin D in their diet.

Improving levels of both minerals could improve bone strength and lower risk of cancer and heart disease.

Foods rich in vitamin D include salmon and mushrooms.

Foods rich in magnesium include avocados and bananas.