RDA for Vitamin D is “Grossly Inadequate”

Introduction:

A huge and growing amount of research has now shown that vitamin D deficiency is very common (at least 50% of the general population and 80% in infants), and plays a major role in the development in many of the chronic degenerative diseases. In fact, vitamin D deficiency may be the most common medical condition in the world, and vitamin D supplementation may be the most cost effective strategy in improving health, reducing disease, and living longer. Those deficient in vitamin D have twice the rate of death and a doubling of risk for many diseases, such as cancer, cardiovascular disease, diabetes, asthma and autoimmune diseases, such as multiple sclerosis.

The optimum blood levels of vitamin D and what constitutes vitamin D deficiency is somewhat controversial in mainstream medicine. For optimum health, most experts recommend blood levels of vitamin D3 (25(OH)D₃) between 50-80 ng/mL (125-200 nmol/L).

Although an individual’s vitamin D requirement may be met through synthesis of vitamin D from 7-dehydrocholesterol in the skin through exposure to sunlight, most people have serum concentration of 25-hydroxyvitamin D in the subnormal range and require treatment with supplemental vitamin D.

A new study published in the Journal of the American Board of Family Medicine demonstrates quite clearly that the RDA for vitamin D is grossly inadequate, and considerably higher dosages than the RDA are required to help meet a person’s vitamin D requirement.

Background Data:
Vitamin D3 acts as a vital key to unlock binding sites on the human genome for the expression of the genetic code. The human genome contains more than 2,700 binding sites for D3; those binding sites are near genes that are involved in virtually every known major disease of humans.

Vitamin D Deficiency Syndrome (VDDS) is newly designated disorder linked to blood levels of D3 less than 25 ng/ml and the presence of at least two of following conditions:

• Osteoporosis
• Heart Disease
• High blood pressure
• Autoimmune disease
• Chronic fatigue
• Cancer
• Allergies
• Asthma
• Psoriasis or Eczema
• Recurrent infections

Risk Factors for Vitamin D Deficiency

• Insufficient exposure to sunlight- working and playing indoors, covering up with clothes or sunscreen when outside, residing at a high latitude.
• Aging – seniors are at greater risk due to lack of mobility and skin that is less responsive to ultraviolet light.
• Darker skin – high incidence of vitamin D deficiency and its associated conditions in Blacks is widely documented. Blacks are at greatest risk of vitamin D deficiency, due to higher skin melanin content.
• Breastfeeding – breastfeeding will result in vitamin D deficiency in the baby if the mother fails to ensure her own levels are high enough to provide for her baby’s needs. When the mother is deficient, the breast-fed child will be deficient due to the low vitamin D content of the mother’s breast milk.
• Obesity – fat-soluble vitamin D gets trapped in fat tissue, preventing its utilization by the body.

New Data:
Researchers from the University of Missouri conducted a study to determine whether the recommended doses of vitamin D3 are adequate to correct deficiency and maintain normal blood levels. They also sought to develop a predictive equation for replacement doses of vitamin D.

They reviewed the response to vitamin D supplementation in 1,327 patients and 3,885 episodes of vitamin D supplementation. For the whole population, the average daily dose resulting in any increase in blood levels of vitamin D3 was 4,707 IU/day; corresponding values for ambulatory and nursing home patients were 4229 and 6103 IU/day, respectively.

The authors concluded that the recommended daily allowance for vitamin D (600 to 800 IU) is grossly inadequate for correcting low blood levels of D3 in many adult patients. They estimated that 5000 IU vitamin D3 per day is usually needed to correct deficiency, and the maintenance dose in adults should be equal to or greater than 2000 IU per day. Furthermore, for people living in nursing homes or not getting any direct sunlight, slightly higher dosages may be necessary.

Commentary:
This new study confirms that most adults need to be supplementing with 2,000 to 5,000 IU of vitamin D3 each day. Of course, the ideal method for determining the exact optimal dosage of vitamin D3 is to get a blood test for 25-hydroxyvitamin D₃ or 25(OH)D₃. Many doctors are now routinely checking vitamin D status in their patients, which is a great service. You can also order a test from www.vitaminDcouncil.org where you collect a small blood sample by skin prick and send it in to the lab. Again, for optimum health, 25(OH)D₃ blood levels should be around 50-80 ng/mL (125-200 nmol/L).

Reference:
Singh G, Bonham AJ. A predictive equation to guide vitamin d replacement dose in patients. J Am Board Fam Med. 2014 Jul-Aug;27(4):495-509.