Tics, muscle spasms and cramps, seizures, anxiety, and irregular heart rhythms are among the classic signs and symptoms of low magnesium. Further symptoms of magnesium deficiency are headaches, insomnia, depression, and chronic fatigue. Magnesium deficiency also increases inflammation markers
Magnesium deficiency is most common in those that have kidney disease, Crohn's or other digestive issues, parathyroid problems, take antibiotics or drugs for diabetes or cancer, older adults or those that abuse alcohol.
Proton Pump Inhibitors (PPI's), which are common medications used for those with acid reflux also often have magnesium deficiency. PPI's include Dexilant, Prevacid, Protonix, Prilosec, Nexium, Aciphex, etc. If these are taken on a long term basis, you should have magnesium levels tested.
High amounts of magnesium are safe, if you get them from food, but getting it from supplements can be toxic. The most one should add in the form of supplements is about 400 mg/day.
Magnesium supplements can interact with some medications, so you should always talk to your doctor or pharmacist, about supplementing, if you take any kind of medication.
It's perfectly okay not to supplement magnesium if you can get what you need from food. The best sources of magnesium are: Green, leafy vegetables, like spinach, Nuts, Beans, peas, and soybeans, Whole-grain cereals. I, personally, avoid all soy products...
If you have symptoms of deficiency, talk to your doctor and ask to be tested. If your levels are sufficient, supplementing will not be beneficial.
I would not take magnesium without some knowledge of your serum levels compared to its reference range. If it is low in the range, then supplementing with a small amount might be beneficial.
You really don't want Vitamin D to be excessive. We usually suggest a minimum of 50. With your level at 55, why does the doctor think you need an increase?
Note the following info on Vitamin D I think you can see that there is no real need for the 10,000 IU per day. .Excessive intakes of vitamin D can lead to high levels of calcium (hypercalcemia). The symptoms of this are weakness, confusion, constipation, loss of appetite, and development of painful calcium deposits.
"To avoid this, keep your supplement intake below the Tolerable Upper Limit per day
4 to 8 years 9 to 18 years 19+ years
IOM 3,000 IU/day 4,000 IU/day 4,000 IU/day
Endocrine Society 4,000 IU/day 10,000 IU/day 10,000 IU/day
This limit is set as the most that a person can consume safely. The arguments against these levels stem from the fact that you can get 10,000-25,000 IU from exposure to the sun in one day. Studies have shown that supplementation over 10,000 IU/day can cause kidney and tissue damage. A recent study found that high-dose vitamin D supplementation (20,000-40,000 IU/week) caused a slight but significant increase in hemoglobin A1C and C-reactive protein, and a decrease in serum HDL. Currently, there are not enough credible studies to support the safety or necessity of taking a supplement in a dose that exceeds the current tolerable upper limits.
Taking magnesium, vitamin D and K are more important if you're taking them with a calcium supplement to help prevent osteoporosis or rebuild bone, as those minerals are needed for the best absorption of calcium.
It's important to note that many/most doctors don't tell us that we need all of them... My doctor put me on calcium, years ago, but didn't bother telling me that I needed the others to help get best absorption...
You can increase your vitamin D level just taking the vitamin D and if that's all you need, you'll probably be fine, but you might want to check with your doctor just to make sure.