Most of us in North America have heard about the importance of vitamin D, but do you know the signs and symptoms of deficiency, and when to know if it’s something you should be supplementing with?
Vitamin D is a fat-soluble vitamin and while a small amount can be found in the diet, most of it is made in the body in response to sun exposure.
A Few Facts About Vitamin D
• Required for the absorption of calcium
• Needed for the proper formation of bones & teeth
• Assists in regulation of the heartbeat
• Aids in healthy thyroid function
• Important for proper blood clotting
• Essential for healthy neuromuscular function
• Helpful in maintaining healthy eyesight
• Enhances immune function (cancer prevention)
• Helps with depression and anxiety
Symptoms of Deficiency
• Muscle aches and pain, weakness
• Bone aches and pain. Bones can feel painful to moderate pressure.
(often more noticeable in the ribs or shin bones)
• Malformation of bones
• Osteomalacia (weakening of the bones – demineralization)
• Osteoporosis (thinning of bones, loss of bone density)
• Myopia (nearsightedness)
• Children with severe deficiency may have soft skull or leg bones. Their legs may look curved (bow-legged).
They may also complain of bone pains, often in the legs, muscle pains or muscle weakness. This condition is known as rickets.
A lack of vitamin D over a period of just a few months can cause the beginning stages of osteomalacia; skeletal demineralization of the spine, pelvis and lower extremities. Signs and symptoms of osteomalacia include: burning in the mouth and throat, bone tenderness, muscle weakness, nervousness, diarrhea, and insomnia.
Causes of Deficiency
• Metabolic abnormalities with absorption or metabolism of vitamin D
• Sedentary indoor lifestyle
• Those who always cover up when outside, including those who wear traditional veils or burqas.
• Regular use of sunblock
• People over the age of 65. The elderly tend to have thinner skin which means it contains less fat/cholesterol to be turned into vitamin D by the sun.
• Having dark skin (darker skin absorbs less vitamin D)
• Liver of gallbladder dysfunction
• Kidney and liver disorders
• Intestinal ailments such as IBS, Crohn’s and celiac disease
• Low fat diets
Types of Vitamin D
There are several forms of vitamin D. D2(ergocalciferol) comes from food sources such as: fish, cod liver oil, eggs, dandelion greens, mushrooms, potatoes, sweet potatoes, alfalfa, nettle, and parsley. Vitamin D3(cholecalciferol) is synthesized in the skin in response to sun exposure. Both types are available in supplement form, D3 being the most active and bioavailable.
Vitamin D has a potential for toxicity. Unless diagnosed with a vitamin D deficiency, supplementing more than 1,000 IU for adults and 400 IU for children is not recommended. Vitamin D is fat-soluble, which means your body has a hard time getting rid of it if you take too much. When you take large amounts of vitamin D, the liver produces a chemical called 25-hydroxy-vitamin D [25(OH)D].
Excess vitamin D increases calcium buildup in the blood and can increase the risk of kidney stones. High blood calcium is a condition called hypercalcemia.
Symptoms of hypercalcemia include: poor appetite or loss of appetite, thirst, frequent urination, abdominal pain, confusion, fatigue, and muscle weakness.
A 25-hydroxy vitamin D test is the most accurate way to measure how much vitamin D is in the body. Testing should be done at least once a year, especially at the beginning of winter. If you are supplementing, monitor your vitamin D levels approximately every 3 months until you are in the optimal range. If you are taking high doses as recommended by your doctor, ask to also have your calcium, phosphorous, and parathyroid hormone levels checked every 3 months.
Since everyone is different, Vitamin D toxicity can happen even at low levels of supplementation. (1)
As a Registered Holistic Nutritionist, my professional opinion is that we should all be supplementing wisely when it comes to fat-soluble vitamins.
• Dangerously Low Levels = Less than 12 ng/mL: Vitamin D deficiency, leading to rickets in infants and children and osteomalacia in adults
• Low Levels = 20-30 ng/mL: Vitamin D insufficiency
• Normal = Greater than 30 ng/mL: Sufficient
• Optimal = 50-80 ng/mL: Recommended
• High = Greater than 100 ng/mL: Emerging evidence links potential adverse effects to such high levels
Vitamin D and Thyroid Conditions
Vitamin D plays an important role in maintaining proper thyroid function and balancing the Th1 and Th2 cells of the immune system. It behaves as a co-hormone, as sufficient levels of vitamin D are essential for proper uptake of thyroid hormones by the cells. Studies show that vitamin D deficiency goes hand-in-hand with hypothyroidism.(2)
Vitamin D and Multiple Sclerosis
Vitamin D deficiency has been associated with numerous autoimmune diseases, including MS. Since vitamin D is absorbed in the small intestine, an inflamed GI tract, which is extremely common in people with multiple sclerosis, reduces its absorption. Many medical doctors prescribe megadoses of vitamin D to patients with MS. It is always wise to have blood serum levels checked before taking high doses of any fat-soluble vitamin.
FACTORS AFFECTING ABSORPTION
Stress and High Cortisol
High cortisol levels caused by stress or medications are also associated with lower vitamin D levels. The synthesis of active vitamin D from sunlight depends on cholesterol. Stress hormones are also made from cholesterol. When the body is in an active stress response, most of the cholesterol is used to make cortisol and not much is left over for the production of vitamin D. (3)
Obesity reduces the bioavailability of active vitamin D. Those who are overweight typically have lower serum levels since it’s extracted from the blood by fat cells, altering its release into the circulation. People with a body mass index of 30 or greater often have low blood levels of vitamin D. (4)
Poor Fat Metabolism
Poor fat metabolism is another factor contributing to malabsorption of this important vitamin. Vitamin D is fat-soluble, which means it requires fat to be absorbed. It also requires conversion by the liver and kidneys before becoming fully active. Those on low-fat diets and people with conditions that impair fat absorption like IBS, IBD, gall bladder dysfunction, liver or kidney disease are more likely to have low levels of vitamin D and are at higher risk for osteoporosis.
Some medications are known to reduce absorption or biologic activity of vitamin D such as antacids, replacement hormones, corticosteroids, anticoagulants, blood thinners and laxatives.
Inflammation of any type reduces the utilization of vitamin D, which is why those with any inflammatory health condition should be following a well balanced, hypoallergenic, anti-inflammatory diet! (5)