Handout PDF download: Dr. Faith Christensen’s Vitamin D Handout
Vitamin D Overview
Vitamin D, calciferol, is a fat-soluble vitamin. It is found in food, but also can be made in your body after exposure to ultraviolet rays from the sun. Vitamin D exists in several forms, each with a different activity. The major biologic function of vitamin D is to maintain normal blood levels of calcium and phosphorus. Vitamin D aids in the absorption of calcium, helping to form and maintain strong bones. It promotes bone mineralization in concert with a number of other vitamins, minerals, and hormones.
Without vitamin D, bones can become thin, brittle, soft, or misshapen. Vitamin D prevents rickets in children and osteomalacia in adults, which are skeletal diseases that result in defects that weaken bones. Infants through elderly populations have been tested in many research studies and a strikingly high rate ranging from 30-70% of people had deficient vitamin D levels.
Other symptoms that may indicate a vitamin D deficiency are muscle weakness, feeling of heaviness in the legs, chronic musculoskeletal pain, fatigue or easy tiring, frequent infections, depression(general or seasonal).
Vitamin D Sources
• Vitamin D supplements are often recommended for exclusively breast-fed infants because human milk may not contain adequate vitamin D. Another option is to check mother’s vitamin D levels and supplement the mother if below optimal.
• Cod liver oil, salmon, mackerel, tuna, sardines, fortified foods (milk, cereal, margarine), eggs, beef liver, swiss cheese. Most contain less than 300 IU per serving. In general, food sources are not high enough in vitamin D to offer adequate amounts without sun exposure or supplementation.
Exposure to Sunlight:
UV rays from sunlight trigger vitamin D synthesis in skin. Up to 20,000 IU can be synthesized by direct sun exposure. Season, latitude, time of day, cloud cover, smog, and sunscreens affect UV ray exposure. For example, in Boston the average amount of sunlight is insufficient to produce significant vitamin D synthesis in the skin from November through February. Tanning beds are also a source of UV rays and if used sparingly can significantly increase vitamin D levels. Care should be taken to limit time to 25% to 50% of the time it would take for the skin to turn a light pink and only go three times a week. Sunscreens with a sun protection factor of 8 or greater will block UV rays that produce vitamin D.
• Calculate sun exposure to receive 5000 IU a day. Visit this site to calculate your specific sun time. You will need the latitude and longitude of your city. For example, one would need 20 minutes of sun exposure every other day on hands face and arms in January in Salt Lake City.
Conditions affected by Vitamin D levels ¹, ²
Arthritis: Progression of degenerative arthritis of the knee and hip is faster in people with lower vitamin D concentrations.
Autoimmune Disorders: Multiple Sclerosis, Sjogren’s Syndrome, rheumatoid arthritis, thyroiditis and Crohn’s disease have all been linked with low vitamin D levels. Single, infrequent, intense, skin exposure to UV-B light suppresses the immune system and causes harm. However repeated low-level exposure to sunlight normalizes immune function and enhances immune cell production. This reduces abnormal inflammatory responses such as found in autoimmune disorders, and reducing occurrences of infectious disease.
Cancer: Vitamin D also acts an effective regulator of cell growth and differentiation in a number of different cell types, including cancer cells. Laboratory, animal, and epidemiological evidence suggest that vitamin D may be protective against some cancers. Clinical studies now show vitamin D deficiency to be associated with four of the most common cancers: Breast, Prostate, Colon and Skin. Recent studies have found that vitamin D levels of 33 ng/ml provided a 50% lower risk of colon cancer and at levels higher than 52 ng/ml provided a 50% lower risk of breast cancer.
Chronic pain: Vitamin D deficiencies have been found in 33 studies looking at chronic pain such as fibromyalgia, myalgia or chronic fatigue syndrome. In these studies 48-100% of the participants were deficient in vitamin D levels. Improvement in pain and muscle strength occurred in studies that supplemented with vitamin D levels. Another study that looked at 360 patients with chronic low back pain with no known cause, identified 83% of the patients were deficient in vitamin D. After supplementation, 95% of patients noted clinical improvement in back pain.
Cardiovascular health: In a study following 51,000 males ages 40-75, only 23% had levels above 30 ng/ml. Researchers followed these men for 10 years and found that men significantly deficient in vitamin D were 200% more likely to have a heart attack. Vitamin D also lowers blood pressure by relaxing the blood vessels and low levels contribute to inflammation and calcification of the vascular walls of blood vessels. Peripheral artery disease is 64% more common in people with vitamin D deficiency.
Diabetes: Vitamin D deficiency has been associated with insulin deficiency and insulin resistance. In fact, last year it was shown that vitamin D deficiency is likely to be a major factor for the development of type one diabetes in children.
Infertility and PMS: Infertility is associated with low vitamin D, and PMS(premenstrual syndrome) has been completely reversed in many women by the addition of calcium, magnesium and vitamin D.
Influenza and colds: Vitamin D boosts bacteria killing white blood cells (macrophages) and enhances the body’s natural antibiotic molecules within the respiratory tract. Studies have shown that vitamin D reduces the frequency of respiratory infections in children. Some researchers have hypothesized that the flu is a symptom of vitamin D deficiency, but more research is needed to prove this. Currently, 2000 IU a day is recommended to combat cold and flu and boost the immune system.
Fatigue, Depression and Seasonal Affective Disorder: Activated vitamin D in the adrenal gland regulates tyrosine hydroxylase, the rate limiting enzyme necessary for the production of dopamine, epinephrine and norepinephrine. Low vitamin D may contribute to chronic fatigue and depression. Seasonal Affective Disorder has been treated successfully with vitamin D. In a recent study covering 30 days of treatment comparing Vitamin D and 2 hour daily use of ‘light boxes’, depression completely resolved in the D group, but not in the light box group.
Obesity: Vitamin D deficiency has been linked with obesity. Vitamin D has recently been shown to lower leptin secretion. Leptin is a hormone produced by fat cells and is involved in weight regulation. Additionally, obesity by itself probably further worsens vitamin D deficiency due to the decreased bioavailability of vitamin D from skin and dietary sources, because of its being deposited in body fat.
Osteoporosis: Vitamin D deficiency has been associated with greater incidence of hip fractures. A greater vitamin D intake from diet and supplements has been associated with less bone loss in older women. Since bone loss increases the risk of fractures, vitamin D supplementation may help prevent fractures resulting from osteoporosis.
Syndrome X: Vitamin D deficiency has been clearly linked with Syndrome X. Syndrome X refers specifically to a group of health problems that can include insulin resistance (the inability to properly deal with dietary carbohydrates and sugars), abnormal blood fats (such as elevated cholesterol and triglycerides), overweight, and high blood pressure.
Vitamin D and Steroids: Steroids, like prednisone, are often prescribed to reduce inflammation from a variety of medical problems. These medicines may be essential for a person’s medical treatment, but they have potential side effects, including decreased calcium absorption and possibly impair vitamin D metabolism.
Current Vitamin D Recommendations
Vitamin D requirements are highly individual and depend on numerous factors, such as the color of your skin, your location, and how much sunshine you’re exposed to on a regular basis. It is impossible to know what an individual’s needs are without checking the blood levels. Much higher doses of vitamin D are used to supplement if blood values are deficient. Blood levels should also be checked periodically to make sure that supplementation is sufficient and to protect against toxic levels.
Current recommendations are to test vitamin D levels in the early fall to identify the highest level of vitamin D after summer sun exposure and in the late spring to identify the lowest level of vitamin D. Seasonal or year round supplementation is recommended based on these two levels.
After beginning supplementation with Vitamin D, it is important to check the value in 1-3 months to monitor levels. Some people need significantly more than 5,000 units if blood levels are deficient. I have seen people requiring 50,000 units of vitamin D a week for 8-16 weeks to reach therapeutic levels.
¹ Dr Mercola?s vitamin D Overview
² Khalsa, Soram. (2009). The vitamin D Revolution. Hay House: Carlsbad, CA.
Written by Dr. Faith Christensen ND, RN
Reprinted with permission of springsnaturalmedicine.com