In The News
Vitamin
D - Not Just for Bones Anymore
New
info about vitamin D, the “sunshine vitamin”, is
reported almost daily increasing our understanding of
the importance of this fat-soluble nutrient. D is
commonly used to prevent the deficiency bone disease
called rickets. We now know that vitamin D has receptors
in almost every cell in the body: Thus making it
important for much more than was originally thought.
Vitamin
D acts like a hormone relaying chemical messages. A
deficiency of vitamin D may play a role in cancers,
auto-immune diseases such as multiple sclerosis, type 1
diabetes, and rheumatoid arthritis. Additionally, mood
disorders, autism, chronic pain, muscle weakness, type 2
diabetes, osteopenia, osteoporosis, infections, obesity
and cardiovascular disease have all been linked to low
levels of vitamin D.
Vitamin
D is made from exposure to sunlight. It is found in
limited amounts in foods: oily fish such as salmon and
mackerel, cod liver oil and egg yolk. To prevent
rickets, foods such as milk, orange juice, cheese,
cereal and breads have been fortified with D.
Unfortunately, because of our fear of exposure to
sunlight and skin cancer very low levels of vitamin D
appear to be common in the population. Even rickets is
making a comeback.
The
Institute of Medicine currently recommends the following
intake of D:
·
200 IU
daily for adults up to age 50
·
400 IU
daily for adults 51 to 70 years of age
·
600 IU
daily over 70
However, these doses do not maintain adequate D levels
and debate is currently going on about how much higher
recommended doses should be. In the past many cautioned
about an excess of vitamin D since it can be stored and
a risk of toxicity was feared. Now it is thought that
doses up to 10,000 IU are likely to be safe. With sun
exposure the body will manufacture thousands of units of
vitamin D safely. But is D taken as a supplement as safe
as that made in the body? No one knows that answer.
Who
needs more Vitamin D?
Almost
everyone it seems. To avoid deficiency and rickets the
American Academy of Pediatrics recommends that children
from infancy through the teen years get 400 IU of D each
day- double the previous recommendation. This is
especially true for infants that are exclusively feed
breast milk because their mothers are often deficient in
vitamin D.
Since D
is a fat soluble vitamin, dietary fat is needed to aid
in its absorption. Low fat dieters are likely to be
deficient in vitamin D.
Sunscreen blocks the ability of the body to make vitamin
D. As little as 10 minutes three times a week of sun
exposure during summer months can improve D levels.
Dark-skinned people are more likely to be D deficient as
darker skin absorbs less sunlight. African –Americans
generally have lower D blood levels and poorer health
outcomes than Caucasians.
The
latitude where you live and time of year effects D
levels. Those of us who reside north of a line drawn
from Los Angeles through South Carolina don’t get enough
sunlight at the right angle to ensure adequate vitamin D
manufacture year round. A recent study found that teens
living in Hawaii getting plenty of sun exposure still
had low D levels.
Consider the Following:
-
Cancer cases increase as the distance from the
Equator increases.
-
Type 1 diabetes is more common in countries where
exposure to sunlight is lower.
-
Increasing cases of asthma especially in
African-American kids may be the result of low D
levels in mothers when pregnant.
-
Higher death rates from all causes and from
cardiovascular disease double in men and women with
below-average vitamin D levels.
-
Research has shown that women with blood levels of
more than 52ng/ml have a 50% lower risk of breast
cancer than those with blood levels of less than 10.
-
Research done on teens and young women in sunny
California found a high prevalence of lower vitamin
D levels and an association of higher BMI and
abdominal fat than those with normal levels.
How to
Measure Vitamin D
Ask
your doctor to order a 25(OH) D level. Currently the
normal lab value is reported as 20-56 ng/ml or 50-140
nmol/l. Keep in mind that normal values are not optimal
values. Optimal levels are often considered to be
30-50ng/ml although some practitioners aim for 60 ng/ml.
Any level below 32 ng/ml should be a red flag.
Once it
has been determined that levels are too low,
supplementation with D3 is the best approach to safely
increasing your levels. Retesting blood levels should be
done after 3 months of regular supplementation.
Doses
and target levels should be individualized. FYI, toxic
levels may occur when 25(OH) D levels exceed 100ng/ml.
Toxicity can result in high blood calcium levels,
anorexia, kidney stones, fever, vomiting, weight loss
and pain.
Until
further and more definitive research clarifies
therapeutic ranges discuss supplementation with your
healthcare provider.
In the
coming year I’m sure we will continue to hear more on
this long-neglected but vital nutrient. What is very
clear now is that vitamin D should be tested on everyone
as a part of a routine exam and dosing individualized
based on lab values, health history and risk factors.
The information presented on this site is in
no way
intended as medical advice or as a substitute for medical treatment.
This information should be used in conjunction with the guidance and
care of your physician. Consult your physician before beginning this
program as you would any weight-loss or weight-maintenance program.
Those of you on diuretics or diabetes medication should proceed only
under a doctor’s supervision as changing your diet usually requires a
change in medication dosages. As with any plan, the weight-loss phases
of this program should not be used by patients on dialysis or by
pregnant or nursing women. As with any weight-loss plan, we recommend
anyone under the age of 18 follow the program under the guidance of
their physician.