Vitamin D: From Sunshine to Supplements

2010 - 2011Family 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, 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 – 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 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?

Thank you!

Sandy Procter, PhD, RDDepartment of Human Nutrition

204 Justin HallManhattan, KS 66506