Vitamin D Toxicity

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Vitamin D toxicity is unlikely at blood levels of less than 100 and when consuming less than 60 I.U. per pound of your body weight. 

Normal levels in your blood should be no less than 35 with the normal range being between 50 and 70.  (Most people's blood levels over the winter in northern climates drop to between 15-18).

Since over 60% of the population is Vitamin D deficient during most of the year, Vitamin D overdoses are rare, however, if you are currently using a tanning bed AND taking high levels of Vitamin D, it is important to know the signs and symptoms of getting too much.

Vitamin D Tests:

The best tests to determine the levels of Vitamin D in your bloodstream report Vitamin D2 and Vitamin D3, separately and as a total amount.  D2 (ergocalciferol) comes from plants and many laboratories do not measure it accurately. 

This is important to know because if you underestimate your actual blood levels, you may overestimate the amount of Vitamin D3 which you need to supplement your low values. 

In his book, The Vitamin D Cure, author and Rheumatologist, James E. Dowd, M.D. cautions that most lab tests can adequately measure 25-hydroxy-Vitamin D3, however most physicians use Vitamin D2 (ergocalciferol) as a replacement for people with severe deficiencies.  Vitamin D2 originates from plants. 

Dr. Dowd recommends the DiaSorin method and HPLC (high performance liquid chromatography) verified with tandem mass spectroscopy as the 2 methods that measure both Vitamin D2 and Vitamin D3. 

PTH Tests:  Dr. Dowd also recommends measuring blood levels of parathyroid hormone (PTH).  PTH is a hormone that comes from the parathyroid gland.  (It is a different gland than your thyroid gland.) 

PTH (Parathyroid Hormone) regulates the metabolism of calcium and phosphorus.  When calcium or Vitamin D levels fall or when phosphorus levels rise, PTH levels also rise.  Rising phosphorus levels in your blood are typically associated with falling calcium levels. 

Falling blood calcium levels and rising phosphorus levels commonly accompany kidney failure.  So, if you are unsure about your kidney function, have your health professional check it, too. 

Normal PTH (Parathyroid Hormone) levels are between 10 and 65 with an ideal range between 10 and 40, preferably below 40.  Higher levels of PTH cause your body to begin to sap calcium and phosphorus from your bones and put it back into your bloodstream.

Vitamin D Overdose Symptoms of Vitamin D Hypervitaminosis:

• Frequent urination


• Nausea
   
• Vomiting
   
• Poor Appetite
   
• Constipation
   
• Muscle Weakness
   
• Weight Loss

Since Vitamin D contributes to increased blood levels of calcium, other Vitamin D "side effects" of taking too much are:

• Increased urination
   
• Dehydration
   
• Lethargy
   
• Mental Confusion

Vitamin D Toxicity

Chronically high blood levels of calcium can cause calcium and phosphate deposits in your skin, muscles,  internal organs, soft tissue damage, kidney damage, digestive upset, headaches and kidney stones. 

Since Vitamin D helps the body synthesize calcium, you probably don't need to take calcium supplements at the same time as Vitamin D, but check with your doctor to make sure. 

More than 600 milligrams of calcium per day (including the calcium in foods you eat), can cause constipation, back pain and possibly kidney stones. 

If you feel you have taken too much Vitamin D or Vitamin A, call your doctor, immediately.  He/She will check your blood levels and from the test results will decide on appropriate treatment.

Vitamin D Half Life

Humans cannot store vitamin D, or any other vitamin.  All bioactive nutrients have a half-life.  A half-life is the length of time the substance is in your body before half of it is used up. 

Unlike Vitamin C which has a half-life of 30 minutes, Vitamin D is a hormone with numerous and variable lengths of activity.  Vitamin D3 (25 hydroxy vitamin D3), measured in blood tests has an approximate 2-1/2 month half-life. 

This means that half of it will be gone from your body in 2-3 months, depending on the amount of sun exposure you receive each day, your diet and your activity (exercise) level.  

Vitamin D Dosage

In the past, calculating Vitamin D intake was based on flat universal dosages (one size fits all).  The newer calculations, based on each person's body weight is much more accurate and a safer method than flat level universal dosage. 

Once you have normalized your D, and eat one or more servings of yogurt or skim milk each day, calcium supplementation is probably unnecessary, as, most people are not low in calcium, they are deficient in Vitamin D. 

Vitamin D Overdose Symptoms

Nausea, vomiting, weakness, poor appetite, constipation and weight loss.

Too much Vitamin D can raise blood calcium levels to abnormal levels and cause mental confusion and heart rhythm abnormalities.

Sun:  Vitamin D toxicity is not obtained because of excessive sun exposure because it is believed that the sun's heat on the skin photodegrades pre-Vitamin D3.

Dietary:  It is unlikely that high dietary intakes of Vitamin D foods will result in Vitamin D toxicity unless large amounts of cod liver oil is consumed.

Supplements:  Large doses of Vitamin D3 over a short period of time do not appear to cause Vitamin D toxicity, because the body can store it in limited amounts for times when exposure to sunlight is limited, such as in the winter. 

Newer clinical trials are being conducted and while the results have not been fully compiled, they point to intakes as high as 10,000 I.U. per day as doing no harm.  Until clinical trials are fully complete, however, if you wish to begin taking higher than daily recommended dosages, consult your doctor or health professional.

In our efforts to increase low blood levels of vitamin D through the use of supplements, as with any herb, vitamin or drug, safety is always the first concern.

If you decide to begin taking Vitamin D supplements for yourself and your family, should you have any of the foregoing signs or symptoms of Vitamin D toxicity, contact your doctor or health care provider at once.