A randomized trial indicates that magnesium optimizes the status of vitamin D, increasing it in individuals with deficient levels and lowering it in individuals with high levels.
This study was published in The American Journal of Clinical Nutrition. This study is important because of controversial discoveries from ongoing study into the association of vitamin D levels with colorectal cancer and other diseases. It also included a recent report from the VITAL trial.
It gave confirmation to a previous observational research in 2013 which linked low magnesium levels with low levels of vitamin D. Some researchers have also discovered that individuals with higher magnesium intakes have higher bone mineral density, and a low osteoporosis risk, than those with lower intakes, the researchers said.
The trial also discovered something new. That magnesium had a regulating effect in individuals with high vitamin D levels. The research provides evidence that magnesium may play a role in the optimization of vitamin D levels. And it may also help in the prevention of conditions related to vitamin D levels.
Qi Dai, MD, Ph.D., Ingram Professor of Cancer Research, was the lead author of the study. He described the ideal level as being in the middle range of a U-shape. This is because at this level vitamin D has been associated with the lowest risk of cardiovascular disease in prior observational studies.
Though, vitamin D was not linked to cardiovascular disease in the latest VITAL trial. He and Martha Shrubsole, are studying the role which magnesium may play with cancer as part of the Personalized Prevention of Colorectal Cancer Trial.
“There’s a lot of information about the relationship between vitamin D and colorectal cancer risk. This information is based upon observational studies versus clinical trials,” Shrubsole said. “But the information is mixed so far.”
Researchers became much interested in a role for magnesium. Because many people synthesize vitamin D differently with vitamin levels in some persons not rising even after high dose supplements. “Magnesium insufficiency stops the vitamin D synthesis and metabolism pathway,” Dai said.
The randomized study involved 250 individuals. These people were considered at risk for developing colorectal cancer. This may be due to either risk factors or having a precancerous polyp removed. Doses of placebo and magnesium were modified based on baseline dietary ingestion.
“Vitamin D deficiency has been recognized as a possible health problem on a large scale in the U.S.,” Shrubsole said. “Many people have received commendations to take vitamin D supplements from their health care providers to increase their levels on the basis of their blood tests.
Along with vitamin D, however, magnesium insufficiency is also an under-recognized problem. Around 80 percent of people do not ingest adequate magnesium in a day. An adequate amount of magnesium is needed by each person to meet the recommended dietary allowance (RDA) based on national estimates.”
Shrubsole emphasized that the magnesium levels were in line with RDA guidelines in the trial. And she suggested dietary changes as the best way of increasing intake. Foods with high magnesium levels include beans, whole grains, dark leafy greens, dark chocolate, fatty fish such as salmon, and avocados.