America’s Most “Popular” Vitamin Kevin Thomas, RD POMH Food and Nutrition Services

Overview  Introduction of Vitamin D  Deficiency  Sources of vitamin D  Reaching “full” potential with vitamin D supplements  Testing for vitamin D

Introduction of Vitamin D  Vitamin D is a fat soluble vitamin (best absorbed with dietary fat)  Can be obtained with food (natural and fortified foods), sun exposure, and supplements. The sun’s ultraviolet-B rays absorbed through the skin are the body’s main source of this nutrient.  The only vitamin obtained from the sun

Introduction of Vitamin D  Vitamin D promotes calcium absorption in the gut and maintains acceptable blood calcium and phosphate concentrations to enable normal mineralization of bone and to prevent low calcium (4)  Bone growth and bone remodeling by osteoblasts (build up) and osteoclasts (breakdown) (4)

Potential Benefits of Optimal Vitamin D (3)  Prevention and treatment of type 1, type 2 diabetes, and Gestational Diabetes  Hypertension (high blood pressure)  Glucose Intolerance  Multiple Sclerosis  Cognition and dementia  Depression  Cancer  Should be noted that the National Institutes of Health (establish federal guidelines) “concluded that it is still not possible to specify a relationship between vitamin D and healthy outcomes other than bone health” (4)

Deficiency  Without sufficient vitamin D, bones can become thin, brittle, or misshapen.  Vitamin D sufficiency prevents rickets in children and osteomalacia (softening of the bones and weakness/pain) in adults.  Together with calcium, vitamin D also helps protect older adults from osteoporosis. (4)

Deficiency Studies indicate that the effects of a vitamin D deficiency include an elevated risk of developing, and dying from (1) :  Cancers of the colon, breast and prostate  High blood pressure and cardiovascular disease  Osteoarthritis  Immune-system abnormalities that can result in infections and autoimmune disorders like multiple sclerosis, Type 1 diabetes and rheumatoid arthritis

Deficiency (4)  Causes of vitamin D deficiency, include:  Levels of sun exposure (office work vs. construction work)  Darkness of a person’s skin  The amount of sunscreen used  Poor food intake  At risk populations, include:  People who are sun-phobic  Babies who are exclusively breast-fed  American Academy of Pediatrics recommends 400IU/day (supplement or formula)  Elderly/nursing homes

Current Trends in Vitamin D & Obesity (8)  Obese subjects had significantly lower vitamin D levels  57% lower vitamin D absorption in obese than in non-obese subjects (given the same sun exposure)  “Because vitamin D is fat soluble and is readily stored in adipose tissue, it could be sequestered (hidden) in the larger body pool of fat of obese individuals  An oral dose of 50,000 IU (prescription level) produced the same vitamin D blood levels and was not significantly different between the obese and non-obese subjects

Recommendations At risk for vitamin D deficiency Less than <12ng/mL Potentially at risk for inadequate vitamin D 12-20ng/mL Sufficient levels> 20ng/mL Optimal levels< 50ng/mL (1) (4)

Current Trends in Vitamin D (1) (4)  Recommended Vitamin D level is ng/mL 20-50ng/mL Caucasians average 18-22ng/mL African-Americans average 13-15ng/mL  African-American women are 10x more likely to have levels at or below 15ng/mL as white women

Lab Assessment  400 IU is the recommended amount for adults and children four or more years of age (5)  “Sun exposure is the body’s main source of this nutrient” vs. American Academy of Dermatology’s recommendation of, “no safe threshold level of UV exposure from the sun.” (6)  Some sun exposure is probably not bad but no validated recommended time recommendations.

Vitamin D sources  Food (small effect)  Sun (medium to large effect)  Supplements (medium to LARGE effect)

Food Sources of vitamin D (4)  Cod Liver oil, 1 Tbsp = 1360 IU  Tuna fish, in water, 3 ounces = 154 IU  Milk, vitamin D-fortified, 1 cup = IU 1mcg = 40 IU (International Units)

Food Sources of vitamin D (4)  Orange juice fortified w/vit D = 100 IU  ½ cup cooked Spinach = 100 IU  Egg, 1 large (vitamin D is found in yolk) = 40 IU  Ready-to-eat cereal = 40IU 1mcg = 40 IU (International Units)

Sunlight and Vitamin D  Geographic latitude does not consistently predict average serum vitamin D levels in a population  Vitamin D from the sun, influenced by:  Season  Time of day  Length of day  Cloud cover  Smog  Skin melanin content  Sunscreen

Sunlight Recommendations (4) (6)  No recommendations for sun exposure. Yet, there are general guidelines, such as:  5-30 minutes of sun exposure between 10am and 3pm at least twice a week to the face, arms, legs, or back, without sunscreen usually lead to sufficient vitamin D (National Institutes of Health)  American Academy of Dermatology:  “There is no scientifically validated, safe threshold level of UV exposure from the sun or indoor tanning devices that allows for maximal vitamin D synthesis without increasing skin cancer risk.”

Vitamin D Supplements  There is a natural “cutoff” of vitamin D when one gets too much direct sunlight.  There is no natural “cutoff” of vitamin D supplementation because it goes directly to the liver when consumed.  Dr. Edward Giovannucci (nutrition researched at Harvard School of Public Health) and Dr. Michael Holick (of Boston University, a leading expert of vitamin D and author of “the Vitamin D Solution”) both state that it is very hard to reach toxic levels (1)  They site a few examples where adults have taken 10,000IU vitamin D per day for 6 months or longer without any adverse effects  Consider that the typical prescription is weekly dosing of 50,000IU until vitamin D level is corrected.

Supplementing Vitamin D

Vitamin D Supplements  Available in soft gels, gummies, and drops  Varies greatly in dosage (normally start at 400IU). Up to 50,000IU.  Cost is usually less than 10 cents per day  Can be taken on an empty stomach but best with food

INSTITUTE OF MEDICINE (IOM) Recommendations (2) (4) Recommended Dietary Allowances (RDAs) for Vitamin D Age MaleFemalePregnancyLactation 0–12 months* 400 IU (10 mcg) 1–13 years 600 IU (15 mcg) 14–18 years 600 IU (15 mcg) 19–50 years 600 IU (15 mcg) 51–70 years 600 IU (15 mcg) >70 years 800 IU (20 mcg) The IOM recommendations were formed assuming the individual has no skin synthesis of vitamin D because of inadequate sun exposure. NHANES survey: Males consume IU/day, Women IU/day

Supplementation  Recommendations vary greatly depending upon the health organization  Aim for supplementation the prevents deficiency but less than toxic amounts  Supplementing with as little as 400IU to as much as 5,000IU per day is fine for most people  Especially important in the winter months, if you tend to stay indoors, or if you are already deficient in vitamin D.

Vitamin D Testing  Not all insurances will cover it  Generally, this would be brought up at a yearly physical  Out-of-pocket costs without insurance is $92.20 (this is subject to change. Call to make certain of the price). x22204  Vitamin D Test Kit $50.00 at Vitamin D Council at test-kit/

Cited Sources DocumentsRegulatoryInformation/LabelingNutrition/ucm ht m 6. Vitamin%20D.pdf 7. the-vitamin-d-my-body-needs/ 8.