Vitamin D: From Sunshine to Supplements Family and Consumer Sciences Lesson

Vitamin D: For Bones, and Beyond! “We estimate that Vitamin D deficiency is the most common medical condition in the world.” Michael Holick, MD, PhD noted Vit. D researcher, Boston U. Med Center Vitamin D Crystals

Participants will…  Recognize key functions of vitamin D  Be able to list three or more diseases associated with low vitamin D levels  Identify ways to improve own vitamin D level

“Sunshine Vitamin” is in the spotlight!  3 out of 4 in U.S. have low levels of vitamin D  Levels down in past 20 years  Research reveals new understanding of our need for vitamin D

Vitamin D then…  Problem recognized for centuries, in form of rickets  In 1919, vitamin D discovered – key to good bone formation  Cod liver oil found to solve deficiency  Vitamin D added to milk in US beginning in 1930s

Vitamin D research now  Low vitamin D levels now linked to: –decreased glucose tolerance –cardiovascular disease –multiple sclerosis –rheumatoid arthritis –types 1 and 2 diabetes –at least 15 types of cancers –chronic gum disease –depression and falls in older adults

We now know…  Vitamin D 3, cholecalciferol, is produced in human skin in presence of sunlight  Is key in mineral metabolism, bone formation with calcium  Not actually a vitamin – functions in the human body as a hormone, targeting over 36 organs!  Vitamin D is stored in the body  Humans make and require vitamin D at different levels, so recommendations are difficult

“D”tails: The Making of Vitamin D in Humans  Wintertime, clouds, sunscreen, smog, body fat and darkly pigmented skin reduce body’s ability – also heavy veils worn in some cultures  Persons who stay inside and have poor diets may have deficiency  Exposure to sunlight cannot cause vitamin D toxicity – only supplements can

How Vitamin D is measured  Blood levels of 25-hydroxyvitamin D [written as 25(OH)D] in healthy persons is best indicator of vitamin D status –Storage form –Determined by simple blood test –Most experts agree that levels below 50 nmol/L (or 20ng/mL) indicate deficiency

Symptoms of Vitamin D deficiency Symptoms are subtle!  Difficult to connect varied symptoms – can affect bones, depression, blood pressure, immunity  Blood test is needed to be certain

How much Vitamin D is enough?  New recommended levels believed adequate amount needed to prevent illness, other deficiency “symptoms”  Some researchers recommending levels at 5000 IU per day, but official recommendations do not support this level  Cannot make leap from basic science to public health recommendations  Individual needs do vary, depending on age and health, diet, skin color, even history of certain diseases & medicines. Obesity may also affect deficiency

New Current DRIs for Vitamin D (in International Units) Life Stage Vitamin D  Infants 0-6 mos 400  7-12 months 400  Children 1-3 yrs 600  4-8 years 600 Males 9-13 years 600  years 600  years 600  years 600  years 600  > 70 years 800

New DRIs for Vitamin D (in IU), cont’d. Females 9-13 years years years years years 600 > Pregnancy < 18 yrs years years 600 Lactation 18 years years years 600

Vitamin D – Essential at all ages

Vitamin D in pregnancy  Emerging research ties pre- eclampsia with low vitamin D levels in pregnancy  Adequate vitamin D in pregnancy may help prevent future cancer, diabetes and heart disease in child  Strong resurgence of rickets since 1990s, in dark-skinned infants who were exclusively breast fed New pregnancy and lactation recommendation of 600 IU per day from foods and supplements

Breast milk and Vitamin D  Recurrence of infant rickets since 1990s, especially in dark-skinned, breastfed infants, points to need for increased vitamin D in the very young  A supplement of 400 IU per day of vitamin D is recommended for all breastfed infants  The vitamin D content of human milk is directly related to the mother’s vitamin D status (Wagner, et al., 2008) Is breast milk lacking by design?

The research says…  A daily vitamin D 3 supplement is necessary for mother during breastfeeding, because the circulating D 3 moves into the milk and affects its anti-ricket activity  Breastfed infants are at risk for vitamin D deficiency

The American Academy of Pediatrics has stepped in…  Increased previous recommended amount for all children, adolescents from birth - age 18  Advises 400 IU supplemental vitamin D each day, beginning within 2 months of birth  New DRIs set at 600 IU for children age 1 or older  A result of evidence of vitamin D’s role in bone health

During childhood…  Vitamin D builds bone in tandem with calcium  Immune system matures with adequacy  Obesity traps vitamin D in body fat – it is made by body but not available for its use  Supplement encouraged in most cases

During adult years…  Possible connections to diseases and medical problems –diabetes –high blood pressure –colon, prostate, breast cancers –autoimmune conditions multiple sclerosis rheumatoid arthritis

Sunlight as vitamin D source  Sunlight is a valuable though uneven source, due to variations in many factors: –Age, wintertime, clouds, sunscreen, smog, body fat and darkly pigmented skin reduce body’s ability – also heavy veils worn in some cultures  Even those exposed to sun may have limited skin area exposed, and still be vitamin D deficient

In Kansas…  Only able to produce vitamin D in the sunlight from March through October –We need to apply sunscreen AFTER 15 minutes of direct sun exposure, in order to maximize vitamin D production –Angle of the sun is too indirect the rest of the time  Supplements are recommended when sunlight is inadequate

Other than the sun…  Vitamin D is found naturally in very few foods –Oily fish Cod Salmon Tuna Swordfish Sardines –Egg yolk –Butter –Liver  Added to milk, in low concentrations

Vitamin D sources, continued…  D 3 is preferred, active form now added to increasing number of foods such as juice, yogurt, cereals  Supplements recommended for most people – often in combination with calcium  Tanning beds NOT considered a safe, dependable method to increase vitamin D levels

Too much of a good thing?  Toxicity is possible, as vitamin D is stored in the body and will build up over time  Excess vitamin D a result of supplements, not from food or sun  Safe upper level (UL) intake also set by IOM –Age dependent –Set at 4,000 IU/day for those age 9 and above –NOT amounts people need or should consume

Big changes have been announced  The Institute of Medicine reviewed recent research, and released new findings on November 30, 2010  “Current evidence does not support benefits beyond bone health, but targeted research should continue.”

Steps you can take…  Talk with your health care provider to see if you need your vitamin D level tested  Let the sun shine – safely! Find out how much sunlight is right for you  Focus on food sources of vitamin D  Ask if your meds affect your vitamin D level  Find out if a supplement is right for you

For more information, go to: Need more info on vitamin D?

Thank you! Sandy Procter, PhD, RD Department of Human Nutrition 204 Justin Hall Manhattan, KS 66506