Cod Liver Oil
Vitamin D Council:
and A on Cod Liver Oil, Vitamin A, and Vitamin D
By Dr. Ben
late 2008, the Vitamin
D Council issued a warning on ingesting cod liver oil due to
concerns about high levels of vitamin A in many brands of cod liver
follows are my answers to the most common queries that I received
on the Vitamin D Council's paper.
you still recommend taking cod liver oil?
but I can only recommend taking cod liver oil made by Carlson Labs,
as this is the brand that I've been taking for several years now.
It's also the brand that I have researched most thoroughly.
guessing that there are other quality brands out there - I just
haven't spent much time researching and trying other brands because
I've been happy with Carlson's product.
are your thoughts on the Council's position that cod liver oil contains
too much vitamin A?
understanding is that different brands of cod liver oil vary greatly
in total vitamin A content.
cod liver oil contains approximately 800 IU of vitamin A per teaspoon.
and scientists aren't in agreement on what a safe upper level of
vitamin A is for the average adult. Some feel that up to 10,000
IU per day is safe. The Institute of Medical Science has marked
3,000 IU per day as being the recommended daily allowance for male
adolescents and adults, and 2,333 IU per day for female adolescents
feeling is that the safe upper limit of vitamin A is different for
each of us and dependent on overall health status and what we regularly
generally, if a person doesn't regularly eat large quantities of
liver or other organ meats that may be high in vitamin A, I feel
that 5,000 IU per day is a safe amount for most adolescents and
adults, assuming that vitamin D and other micronutrient statuses
are in healthy ranges.
the 5,000 IU mark in mind, the average adolescent or adult should
be able to safely take about 6 teaspoons of Carlson cod liver oil
per day. But to tread conservatively and take into account each
individual's body weight, I typically recommend taking about 1 teaspoon
per 50 pounds of body weight per day.
those who wish to be even more conservative, my feeling is that
taking just 1 teaspoon of Carlson cod liver oil per day is perfectly
safe, and provides amounts of vitamin A, D, and omega-3 fatty acids
that can make positive differences in overall health status.
the issue that there is too much vitamin A relative to D in cod
John Cannell, head of the Vitamin D Council, suggests that "The
key is having the proper ratio of vitamin D to vitamin A in your
Cannell also suggests that the best way to obtain the proper ratio
of vitamin D to vitamin A is to eat a variety of colorful vegetables
that are rich in carotenoids, which a healthy body can convert to
vitamin A, and to obtain vitamin D by taking "1,000 IU of vitamin
D3 per every 25 pounds of body weight in the winter and stop all
vitamin D in the summer and sunbathe."
an alternative to sunbathing when the sun is too low in the horizon
to do so, Dr. Cannell suggests using a tanning bed.
line: The general consensus among members of the Vitamin D Council
is that there is too much vitamin A in cod liver oil, enough to
increase deleterious effects on vitamin D function and overall health.
reality - one that all physicians and scientists can agree upon
- is that our vitamin A and D levels are constantly in flux, with
precise levels determined by what we're eating and how much sunlight
we're being exposed to, and this has been true for all humans throughout
the history of our world.
highlighting the importance of maintaining a proper ratio of vitamin
D to vitamin A to promote optimal health, my feeling is that Dr.
Cannell is encouraging people to rely on natural sources rather
than risk disruptions to our health by taking high doses of vitamin
fact that no specific ratio was stated as being optimal supports
the idea that the Vitamin D Council's suggestions are meant to encourage
avoidance of cod liver oil that contains high levels of vitamin
is why I feel Carlson's cod liver oil is a good choice among the
many brands out there - the ratio between vitamin A and vitamin
D in Carlson's brand is about 2 to 1. Apparently, there are some
brands of cod liver oil that are at 5 to 1 and even 10 to 1.
is the ratio between vitamin A and vitamin D different among different
understanding is that some companies add extra vitamin A or D during
the manufacturing process.
doesn't add any extra vitamin A; the amount of vitamin A in the
final product is all naturally occurring.
does blend in extra vitamin D (from cod liver oil) when necessary
to ensure that the final product contains approximately 400 IU of
vitamin D per teaspoon.
is the recommended dose for children?
doses are as follows:
children 2-4 years of age: half a teaspoon of Carlson cod liver
oil per day, providing approximately 400 IU of vitamin A.
children 4 years or older: 1 teaspoon of Carlson cod liver oil per
day, providing approximately 800 IU of vitamin A.
children younger than 2 years of age: I feel that breast milk from
a healthy mother is the best source of all nutrients for at least
the first 6 months. After the 12-month mark, my feeling is that
half a teaspoon of Carlson cod liver oil is a good amount, but it's
best to consult with one's personal physician on this.
take cod liver oil anyway?
don't have to take cod liver oil to experience your best health.
I use and recommend taking cod liver oil by Carlson because it's
an excellent source of omega-3
fatty acids, vitamin A, and vitamin D - if you'd like to know
the health benefits of making sure that you are getting enough of
these nutrients, please do a quick search for them using the search
bar at the top of this page.
you can get sunlight exposure on bare skin during warmer months,
I think it's better to use fish oil, which provides omega-3 fatty
acids, but doesn't contain vitamin A or vitamin D.
sunlight in warm weather isn't available, my feeling is that one
needs more vitamin D than what Carlson cod liver oil provides in
the doses that I recommend. So on top of taking Carlson cod liver
oil whenever one can't make vitamin D from sunlight exposure, it's
important to consider getting vitamin D from other sources as well,
a good one being a high quality D3 supplement.
much vitamin D is needed every day for optimal health?
one knows for sure, and the answer varies for each individual based
on health status, diet, and sunlight exposure, but to be conservative,
my feeling is that it's best to get at least 1,000 IU per day from
all sources (sunlight, diet, supplements).
evidence indicates that even up to about 10,000 IU of vitamin D
per day isn't toxic, but my feeling is that it's always best to
be conservative, especially when dealing with fat-soluble nutrients
like vitamins A, D, E, and K.
upper limit for vitamin D is about 2,000 IU per day, in my opinion.
Cannell recommends that people avoid taking vitamin A (not carotenoids)
"unless you have a bowel disease that impairs absorption of vegetables
and transportation of carotenoids" - what do you think about this?
seen enough strict vegans who have relied solely on carotenoids
for vitamin A and who have displayed signs of vitamin A deficiency
for me to believe that this is the best stance on vitamin A supplementation.
understanding is that poor absorption of carotenoids is more prevalent
than most physicians imagine - more information on this topic can
be accessed from the following study:
absorption is poor and variable even under ideal conditions.
it's certainly possible to meet all of one's vitamin A requirements
from carotenoids found in plant foods - it's just not a given for
everyone, and all physicians should know this.
the main nutrient in question by the Vitamin D Council's report
is vitamin A, for reference, here is a table that shows the recommended
daily allowance for vitamin A for different age groups and genders,
as created by the Institute of Medical Science in 2001:
(RDA) for Vitamin A as Preformed Vitamin A (Retinol Activity
years and older
years and younger
years and older
years and younger
years and older
a look at the two Carlson products that I use and recommend, please
feel free to view the following links:
Cod Liver Oil (Omega-3 fatty acids, vitamin A, and vitamin D)
Fish Oil (Just omega-3 fatty acids, no vitamin A or vitamin D)
you have any thoughts on this topic, please feel free to share via
the comment feature in the article tools box below. Thank you.
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