vitamin d: from sunshine to supplements 2010 - 2011 family and consumer sciences lesson
TRANSCRIPT
Vitamin D: For Bones, and Beyond!
“We estimate that
Vitamin D deficiency
is the most common
medical condition in
the world.”
Michael Holick, MD, PhDnoted 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 D3, 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 bodyHumans 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 600Males 9-13 years 600 14-18 years 600 19-30 years 600 31-50 years 600 51-70 years 600 > 70 years 800
New DRIs for Vitamin D (in IU), cont’d.
Females 9-13 years 60014-18 years 600 19-30 years 60031-50 years 600 51-70 years 600>70 800
Pregnancy < 18 yrs 600 19-30 years 600
31-50 years 600 Lactation 18 years 600
19-30 years 600 31-50 years 600
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 D3 supplement is necessary for mother during breastfeeding, because the circulating D3 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 adequacyObesity traps vitamin D in body fat – it is
made by body but not available for its useSupplement 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 lowconcentrations
Vitamin D sources, continued…
D3 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:
http://ods.od.nih.gov/factsheets/VitaminD-Consumer.asp
Need more info on vitamin D?