Vitamin D Deficiency & Feeling Tired

On November 30th, 2010, the Institute of Medicine revised their recommendations to increase vitamin D supplementation with the hope of preventing deficiencies that are especially prominent during the winter. As you lose your vitamin D stores accumulated in the sunny summer months, you may feel weak, tired or more likely to get sick when it is not sustained in your diet. Vitamin D lives up to its many titles such as calciferol or the sunshine vitamin, with the power to enhance bone formation, strengthen the immune system, decrease risks of autoimmune disorders, enhance calcium and phosphate absorption, inhibit parathyroid hormone secretion and stimulate pancreatic insulin production.

Significance

Vitamin D is considered a pro-homone and deficiencies are common in places without adequate sunlight. A deficiency in vitamin D partners with low calcium levels, which stimulates the production of parathyroid hormones, or PTH. This causes bone mobilization and renal conservation of calcium that also increases the excretion of phosphate, resulting in weak bones and muscles that contribute to lethargy. Rickets, common in children; osteomalacia, common in adults; and the exacerbation of osteoporosis are all related to low vitamin D levels. A study published in 2008 from the Archives of Internal Medicine shows that a deficiency in vitamin D not only increases generalized muscle and bone weakness and aches, it also increases the risk of atherosclerosis and heart disease.

Mechanism and Identification

Dietary vitamin D3 or D2 forms must be metabolized by your liver and kidney enzymes to become the active form, 1,25-dihydroxyvitamin D, used by your body. 25-hydroxyvitamin D, or 25(OH)D, is the form stored in your tissues that determines the levels in your body. According to the Vitamin D Council, you do not reliably begin to store 25(OH)D until levels reach 50ng/ml or 125nmol/L. Doctors who make the mistake of ordering a 1,25-dihydroxyvitamin D test will only see the adaptive effects of calcium intake and not actual vitamin D stores. If your levels fall below 30ng/ml, you may want to increase dietary intake or start supplementing to prevent feeling tired and weak. Routine screening is suggested.

Food Sources

Fish liver oils, salt water fish, shrimp, whole eggs and liver are good sources of vitamin D. In some developed countries, vitamin D-fortified dairy products such as milk and cheeses and foods such as cereals are common. Eating foods high in vitamin D is crucial to support your bone and muscle health and your immune system, and also promotes heart health especially if you have the habit of putting on sunscreen daily or do not receive enough sunlight. Acquiring vitamin D from your diet is the safest way to sustain levels during periods of low sun exposure.

How Much Sunlight In A Day?

If you have access to sunlight daily, all you need is a little dose of the warm rays every day to keep the doctors away. As the vitamin D levels are restored on a constant basis, the less likely you are to feel tired from a deficiency. Skin synthesis of vitamin D declines with age as the requirements for vitamin D increase. The darker your skin is, the more you are protected against skin cancer; however, darker skin also decreases your ability to absorb UVB rays. According to a report in US News, depending on how much skin is exposed and the time of day, you may only need a few minutes without sunscreen. If you are already tan, 15 to 20 minutes is usually enough exposure before applying adequate sunscreen.

Supplementation

With adequate exposure to sunlight, supplementation is not required. The Mayo Clinic states that the D3 form, cholecalciferol, is naturally synthesized by your skin during sun exposure. The D2 form, ergocalciferol, is synthesized by plants and not as bio-available to your body. The recommendations published by the Institute of Medicine as of 2010 are 600 IUs for individuals over 1 year of age and 800 IUs for those over 70. Vitamin D is fat soluble and should be consumed with meals to aid with absorption. Excessive intake is toxic over long periods so taking more than 4,000 IUs a day for individuals past age 1 is not recommended. Always consult your doctor before beginning any new regimen.