Problems With Vitamin D

FAT SOLUBLE VITAMINS: Overlooked and Misunderstood
The Failure of the Drug Model:  Why Vitamin D Isn’t Enough

Are you taking a vitamin D supplement?  Is your 25 hydroxy vitamin D level (25 OH vitamin D) in the optimal range between 40 and 60 ng/ml)?  The answer to both questions may be”yes”, but you may be at risk for vitamin A deficiency. What I’m about to tell you is a recent concern of the scientific community and leads us to a path of moderation the use of supplements.

Vitamin D may be the “Nutrient of the Decade”.  A combination of factors — sun phobia, dietary fat phobia and an increasingly sedentary lifestyle — have created a vitamin D deficiency pandemic.  Over 50% of Americans are deficient in this vital nutrient. 

Vitamin D is essentially captured sunlight.  Fear of skin cancer has caused us to reduce our exposure to the sun, possibly to our detriment.  Vitamin D is a fat soluble nutrient, meaning it is found in dietary fat — mainly fatty fish (salmon, sardines, mackerel, herring) and full fat dairy.  Fear of dietary fat has compounded the difficulties of getting enough vitamin D from the few available food sources.  Sitting around indoors behind a desk, in front of a TV or behind the wheel of an automobile also limits sun exposure.

An abundance of research has led to the widespread use of vitamin D supplementation.  And why not?  Since 1979 researchers have identified over 50 target tissues for vitamin D in the body, including brain, bone, heart, liver, muscle, kidneys and intestines.  Vitamin D helps regulate mood, heart function, calcium absorption, growth, immune function and hormones.  Low levels of vitamin D are associated with increased risk of heart attack, depression, hip fracture and early death –compelling evidence to support aggressive supplementation.  Many patients are now routinely prescribed as many as 5000 International Units (IUs) of vitamin D a day, sometimes more.

Single-minded focus on Vitamin D in a drug model fashion (one nutrient isolated from another) can cause vitamin A deficiency.  Vitamin A, or retinoic acid, is also fat soluble.  Because retinoic acid is found in what many still regard as health threatening animal foods, especially animal organ meats and full fat dairy foods, so-called experts have encouraged the consumption of plant source pre-vitamin A in the form of beta carotene.  Many supplements now include vitamin A only as its pre-vitamin beta carotene or carotenoid form.  This may be OK for some, but recent research from England suggests that up to 50% of the population has trouble converting beta carotene to its active retinoic acid form.  

Vitamins D and A share the same receptor and engage in regular cross-talk.  The basic concept is simple — they work as as a team and we humans have been used to getting together in food for ages.  Examination of healthy traditional diets shows us that vitamin A rich foods –organ meats and full fat dairy, for example — were highly valued. 

Because vitamins D and A share a common receptor in the nucleus of the cell (known as the retinoid X receptor) means we need to receive these two nutrients into our bodies in a balanced way.  Adding one nutrient in large amounts to the exclusion of the can cause a deficiency in the other. 

When you take high daily doses of vitamin D without adequate amounts of retinoic acid, you risk vitamin A deficiency.  And as I indicated above, getting vitamin A from plants in carotenoid forms may not be enough.   Vitamin A deficiency disturbs immune functioning and can increase your susceptibility to infection, specifically in the mucus lined tissues of the respiratory, urinary and digestive tracts. 

So how much vitamin D should you take? How much vitamin A?  Without going into fine detail, 1000 – 2000 IUs of vitamin D are enough for most.  Up to 10,000 IUs daily of  vitamin A (retinoic acid) is regarded as safe — if teamed up with vitamin D. 

An elegant strategy for achieving these levels is to use cod liver oil.  But which cod liver oil?  There are several products that contain very small amounts of vitamin D per serving (e.g. 40 IUs) along with large amounts of retinoic acid (usually several thousand).  Avoid these.

High quality products from Carlson’s and Nordic Naturals contain balanced amounts of both vitamins, but they are heat processed, which destroys potentially valuable nutrients.  On the other hand, fermented cod liver does not require high heat; the enzyme processing methods for fermented cod liver oil preserve nutrients, but it is expensive and takes about six months to arrive at a the final product.

The fermented cod liver I use and recommend is the Blue Ice brand from Green Pastures (  One serving (2 capsules) supplies 360 IUs of vitamin D and and 3000 units of vitamin A (retinoic acid).  Two to four capsules daily should be enough if you include fatty fish in your diet. If you’re not enjoying regular servings of fatty fish several times a week, consider adding 1000 IUs of vitamin D in gel capsule form.  Carlson’s makes just such a product that is inexpensive and easily obtainable on the internet ( Fermented cod liver oil is a reasonable “closest to food” solution to your body’s need for both vitamin D and A as well as the all-important marine source omega 3 fatty acids.  I believe cod liver oil products from Carlson’s and Nordic Naturals are also reasonable choices, with adequate amounts of both vitamins.  As a general rule, however,”closer to food” is usually better for your health, which is why I prefer fermented cod liver oil.

Next week we’ll talk more about the how’s and why’s of balancing the all-important fat soluble vitamins — A, D, K and E — in your diet. Fear and misunderstanding of healthy, natural fats continues to jeopardize the health of many health conscious Americans.

I have no financial connection to any of the abovementioned companies.

One comment

  • Dr. Inglis, I used to get your newsletter in the mail, but it eventually stopped being printed. I found this web site through google & am happy to have found you at this web site. I also was getting e-mails from you “The Country Doctor” with priceless information. Could I be put on your list to get e-mail updates from you? Thank you

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