Monday, July 23, 2007

Fat Soluble Vitamins---Vitamin A and WLS

Vitamins A, D, E and K are all classified as fat soluble vitamins - since they are soluble in fat and are absorbed by the body from the intestinal tract. They follow the same path of absorption as fat and any condition interfering with the absorption of fats would result in poor absorption of these vitamins as well. This class of vitamin can be stored in the body to some extent, mostly in the liver, and because of this, short term deficiencies are less likely to manifest themselves slower than the water-soluble vitamins.

All this being said, Vitamin A deficiency can occur years later in those who have WLS. It's the nature of the beast, so to speak, as I wrote about in this post. Due to the malabsortive properties of the RNY procedure of WLS, many vitamins depend on just where and how they are absorbed to be effective. Fat soluble vitamins are particularly difficult. This is from Linus Pauling Institute of Oregon State University:

Vitamin A is a generic term for a large number of related compounds. Retinol (an alcohol) and retinal (an aldehyde) are often referred to as preformed vitamin A. Retinal can be converted by the body to retinoic acid, the form of vitamin A known to affect gene transcription. Retinol, retinal, retinoic acid, and related compounds are known as retinoids. Beta-carotene and other carotenoids that can be converted by the body into retinol are referred to as pro vitamin A carotenoids. Hundreds of different carotenoids are synthesized by plants, but only about 10 % of them are pro vitamin A carotenoids

Vitamin A plays a major role in many bodily functions Vision, Regulation of gene expression, Immunity, Growth and development, Red blood cell production, and Nutrient interactions (works with zinc and iron). In vision retinol plays a major role in night vision.


Retinoic acid (RA) and its isomers act as hormones to affect gene expression and thereby influence numerous physiological processes.

Regulation of gene expression

Through the stimulation and inhibition of transcription of specific genes, retinoic acid plays a major role in cellular differentiation, the specialization of cells for highly specific physiological roles. Most of the physiological effects attributed to vitamin A appear to result from its role in cellular differentiation.


Vitamin A is commonly known as the anti-infective vitamin, because it is required for normal functioning of the immune system. The skin and mucosal cells (cells that line the airways, digestive tract, and urinary tract) function as a barrier and form the body's first line of defense against infection. Retinol and its metabolites are required to maintain the integrity and function of these cells. Vitamin A and retinoic acid (RA) play a central role in the development and differentiation of white blood cells, such as lymphocytes that play critical roles in the immune response. Activation of T-lymphocytes, the major regulatory cells of the immune system, appears to require all-trans RA binding of RAR.

Growth and development

Both vitamin A excess and deficiency are known to cause birth defects. Retinol and retinoic acid (RA) are essential for embryonic development. During fetal development, RA functions in limb development and formation of the heart, eyes, and ears. Additionally, RA has been found to regulate expression of the gene for growth hormone.

Red blood cell production

Red blood cells, like all blood cells, are derived from precursor cells called stem cells. These stem cells are dependent on retinoids for normal differentiation into red blood cells. Additionally, vitamin A appears to facilitate the mobilization of iron from storage sites to the developing red blood cell for incorporation into hemoglobin, the oxygen carrier in red blood cells.

Nutrient interactions
  • Zinc
Zinc deficiency is thought to interfere with vitamin A metabolism in several ways: 1) Zinc deficiency results in decreased synthesis of retinol binding protein (RBP), which transports retinol through the circulation to tissues (e.g., the retina). 2) Zinc deficiency results in decreased activity of the enzyme that releases retinol from its storage form, retinyl palmitate, in the liver. 3) Zinc is required for the enzyme that converts retinol into retinal. At present, the health consequences of zinc deficiency on vitamin A nutritional status in humans are unclear.

  • Iron
Vitamin A deficiency may exacerbate iron deficiency anemia. Vitamin A supplementation has been shown to have beneficial effects on iron deficiency anemia and improve iron nutritional status among children and pregnant women. The combination of vitamin A and iron seems to reduce anemia more effectively than either iron or vitamin A alone.

As you can see from this---Vitamin A is just one of the keys to good health for anyone---but as it pertains to those of us who have undergone WLS---it is so much more than that. Because we have difficulty tolerating fat. Well some of you do, I don't. Also I've found some interesting research about this whole fat tolerance. But that is for another post.

The thing is---because of the bypass of the upper portion of the small intestine in the RNY surgery---we don't absorb fat as easily. Hence we don't absorb fat soluble vitamins as easily---ergo we are very susceptible to Vitamin A deficiency. The main points as far as deficiency go as related to WLS have to do with the role it plays with iron and zinc as stated above. Here are 2 additional key points about this deficiency.

Vitamin A deficiency and vision

Vitamin A deficiency among children in developing nations is the leading preventable cause of blindness. The earliest evidence of vitamin A deficiency is impaired dark adaptation or night blindness. Mild vitamin A deficiency may result in changes in the conjunctiva (corner of the eye) called Bitot's spots. Severe or prolonged vitamin A deficiency causes a condition called xeropthalmia (dry eye), characterized by changes in the cells of the cornea (clear covering of the eye) that ultimately result in corneal ulcers, scarring, and blindness.

This has been shown to happen even years after WLS. Sometimes leading to BLINDNESS. Yep, that's right. You can go completely blind from not having enough absorption of Vitamin A. Check this out: Vitamin A Deficiency Related to GI Surgery Can Occur Years Later You will have to register to be able to access the info. Here are some highlights:

Intestinal surgery may result in malabsorption of vitamin A, with ocular symptoms manifesting years or even decades after surgery, especially when other comorbidities are present, ophthalmologists report.

Drs. Chae and Foroozan, of the Baylor College of Medicine in Houston, reviewed the records of patients diagnosed with vitamin A deficiency from January through December 2005. The researchers detected four cases related to GI surgery; one patient developed ocular symptoms within months of gastric bypass surgery, while the other three did not have visual symptoms until at least 18 years after intestinal surgery.

The first was a 69-year-old man who reported 4 months of night blindness. He had undergone intestinal bypass surgery 20 years earlier.

The second patient was an 80-year old man presenting with 4 months of decreased vision in the right eye that was worse in dim light. Thirty-six years earlier he had undergone partial small and large bowel resection for ruptured ileum related to Crohn's disease.

The third patient reported several months of decreased vision in both eyes that was worse at night. Her medical history included "multiple abdominal surgeries 18 to 20 years earlier as a result of complications from a cholecystectomy.

In a related editorial, Dr. W. B. Lee and Dr. I. R. Schwab point out that other investigators have reported severe visual complications, including blindness, that followed gastric bypass surgery resulting in malabsorption of vitamin A.

I don't know about y'all, but that scares the begeezes out of me. The fact that even years after having this surgery I may go through this. :shudders:
Here's some more of that article:

The two male patients were treated with intramuscular injection of vitamin A, and both reported improvements in vision in both eyes within the first week. The woman refused further treatment and was lost to follow-up.

Dr. Chae and Dr. Foroozan recommend that "vitamin A deficiency should be suspected in patients with unexplained decreased vision and a history of intestinal surgery, regardless of the timing of the surgical procedure."

Well at least there is some hope for reversal of the symptoms. That is good to know.
Vitamin A also plays a role in the immune system. I don't know about y'all, but I don't like being sick. Hell, I don't know of too many people who actually enjoy being sick.

Vitamin A deficiency and infectious disease

Vitamin A deficiency can be considered a nutritionally acquired immunodeficiency disease. Even children who are only mildly deficient in vitamin A have a higher incidence of respiratory disease and diarrhea, as well as a higher rate of mortality from infectious disease, than children who consume sufficient vitamin A. Supplementation of vitamin A has been found to decrease the severity of and deaths from diarrhea and measles in developing countries, where vitamin A deficiency is common.

This is what the RDA recommends for Vitamin A supplementation:

Recommended Dietary Allowance (RDA) for Vitamin A as Preformed Vitamin A (Retinol)
Life Stage Age Males: mcg/day (IU/day) Females: mcg/day (IU/day)
Infants 0-6 months 400 (1333 IU) 400 (1333 IU)
Infants 7-12 months 500 (1667 IU) 500 (1667 IU)
Children 1-3 years 300 (1000 IU) 300 (1000 IU)
Children 4-8 years 400 (1333 IU) 400 (1333 IU)
Children 9-13 years 600 (2000 IU) 600 (2000 IU)
Adolescents 14-18 years 900 (3000 IU) 700 (2333 IU)
Adults 19 years and older 900 (3000 IU) 700 (2333 IU)
Pregnancy 18 years and younger - 750 (2500 IU)
Pregnancy 19-years and older - 770 (2567 IU)
Breastfeeding 18 years and younger - 1,200 (4000 IU)
Breastfeeding 19-years and older - 1,300 (4333 IU

Now this is for NORMAL people. As someone who has had WLS, you are never NORMAL again. Your whole entire life is different. That again is something for another post. Anyway back to the topic at hand.

As far as vitamins go most people think if 1 tab is good than 2 is twice as good. That you can never get enough of a good thing. That is not always the case. There can be major problems associated with getting too much Vitamin A. But how much is too much??? First let's talk about what having too much can do to your body.

It is important to note that treatment with high doses of natural or synthetic retinoids overrides the body's own control mechanisms, and therefore carries with it risks of side effects and toxicity. Additionally, all of these compounds have been found to cause birth defects. Women who have a chance of becoming pregnant should avoid treatment with these medications. Retinoids tend to be very long acting; side effects and birth defects have been reported to occur months after discontinuing retinoid therapy.


The condition caused by vitamin A toxicity is called hypervitaminosis A. It is caused by overconsumption of preformed vitamin A, not carotenoids. Preformed vitamin A is rapidly absorbed and slowly cleared from the body, so toxicity may result acutely from high-dose exposure over a short period of time, or chronically from much lower intake. Vitamin A toxicity is relatively rare. Symptoms include nausea, headache, fatigue, loss of appetite, dizziness, and dry skin. Signs of chronic toxicity include, dry itchy skin, loss of appetite, headache, and bone and joint pain. Severe cases of hypervitaminosis A may result in liver damage, hemorrhage, and coma. Generally, signs of toxicity are associated with long-term consumption of vitamin A in excess of 10 times the RDA (8,000 to 10,000 mcg/day or 25,000 to 33,000 IU/day). However, there is evidence that some populations may be more susceptible to toxicity at lower doses, including the elderly, chronic alcohol users, and some people with a genetic predisposition to high cholesterol (9). In January 2001, the Food and Nutrition Board (FNB) of the Institute of Medicine set the tolerable upper level (UL) of vitamin A intake for adults at 3,000 mcg (10,000 IU)/day of preformed vitamin A.

Tolerable Upper Level of Intake (UL) for Preformed Vitamin A (Retinol)
Age Group UL in mcg/day (IU/day)
Infants 0-12 months 600 (2,000 IU)
Children 1-3 years 600 (2,000 IU)
Children 4-8 years 900 (3,000 IU)
Children 9-13 years 1,700 (5,667 IU)
Adolescents 14-18 years 2,800 (9,333 IU)
Adults 19 years and older 3,000 (10,000 IU)

So since our absorption of vitamin is remarkably decreased for several reasons, we really should be taking the maximum allowed without fear of toxicity. It would be safe to state, that 10,000 IU would be our recommended dose.

But where do you get Vitamin A from? Can you take it in a pill?? Can you get it from eating whole foods alone??? This is what I have found.

Retinol activity equivalency (RAE)

Different dietary sources of vitamin A have different potencies. For example, beta-carotene is less easily absorbed than retinol and must be converted to retinal and retinol by the body. The most recent international standard of measure for vitamin A is retinol activity equivalency (RAE), which represents vitamin A activity as retinol. Two micrograms (mcg) of beta-carotene in oil provided as a supplement can be converted by the body to 1 mcg of retinol giving it an RAE ratio of 2:1. However, 12 mcg of beta-carotene from foods are required to provide the body with 1 mcg of retinol, giving dietary beta-carotene an RAE ratio of 12:1. Other provitamin A carotenoids in foods are less easily absorbed than beta-carotene, resulting in RAE ratios of 24:1. The RAE ratios for beta-carotene and other provitamin A carotenoids are shown in the table below. An older international standard, still commonly used, is the international unit (IU). One IU is equivalent to 0.3 mcg of retinol.

Retinol activity equivalency (RAE) ratios for beta-carotene and other provitamin A carotenoids
Quantity Consumed Quantity Bioconverted to Retinol RAE ratio
1 mcg of dietary or supplemental vitamin A 1 mcg of retinol* 1:1
2 mcg of supplemental beta-carotene 1 mcg of retinol 2:1
12 mcg of dietary beta-carotene 1 mcg of retinol 12:1
24 mcg of dietary alpha-carotene 1 mcg of retinol 24:1
24 mcg of dietary beta-cryptoxanthin 1 mcg of retinol 24:1

*One IU is equivalent to 0.3 mcg of retinol, and one mcg of retinol is equivalent to 3.33 IU of retinol.

Food sources

Free retinol is not generally found in foods. Retinyl palmitate, a precursor and storage form of retinol, is found in foods from animals. Plants contain carotenoids, some of which are precursors for vitamin A (e.g., alpha-carotene and beta-carotene). Yellow and orange vegetables contain significant quantities of carotenoids. Green vegetables also contain carotenoids, though the pigment is masked by the green pigment of chlorophyll (1). A number of good food sources of vitamin A are listed in the table below along with their vitamin A content in retinol activity equivalents (mcg RAE). In those foods where retinol activity comes mainly from provitamin A carotenoids, the carotenoid content and the retinol activity equivalents are presented. You may use the USDA food composition database to check foods for their content of several different carotenoids, including lycopene, lutein and zeaxanthin.

Food Serving Vitamin A, RAE
Vitamin A, IU Retinol, mcg Retinol, IU
Cod liver oil 1 teaspoon 1,350 mcg 4,500 IU 1,350 mcg 4,500 IU
Fortified breakfast cereals 1 serving 150-230 mcg 500-767 IU 150-230 mcg 500-767 IU
Egg 1 large 91 mcg 303 IU 89 mcg 296 IU
Butter 1 tablespoon 97 mcg 323 IU 95 mcg 317 IU
Whole milk 1 cup (8 fl ounces) 68 mcg 227 IU 68 mcg 227 IU
2% fat milk (vitamin A added) 1 cup (8 fl ounces) 134 mcg 447 IU 134 mcg 447 IU
Nonfat milk (vitamin A added) 1 cup (8 fl ounces) 149 mcg 500 IU 149 mcg 500 IU
Sweet potato 1/2 cup, mashed 959 mcg 3,196 IU 0 0
Carrot (raw) 1/2 cup, chopped 385 mcg 1,283 IU 0 0
Cantaloupe 1/2 medium melon 466 mcg 1,555 IU 0 0
Spinach 1/2 cup, cooked 472 mcg 1,572 IU 0 0
Squash, butternut 1/2 cup, cooked 572 mcg 1,906 IU 0 0


The principal forms of preformed vitamin A (retinol) in supplements are retinyl palmitate and retinyl acetate. Beta-carotene is also a common source of vitamin A in supplements, and many supplements provide a combination of retinol and beta-carotene. If a percentage of the total vitamin A content of a supplement comes from beta-carotene, this information is included in the Supplement Facts label under vitamin A. Most multivitamin supplements available in the U.S. provide 1,500 mcg (5,000 IU) of vitamin A, substantially more than the current RDA for vitamin A. This is due to the fact that the Daily Values (DV) used by the FDA for supplement labeling are based on the RDAs established in 1968 rather than the most recent RDAs, and multivitamin supplements typically provide 100% of the DV for most nutrients. Because retinol intakes of 5,000 IU/day have recently been associated with an increased risk of osteoporosis in older adults, some companies have reduced the retinol content in their multivitamin supplements to 750 mcg (2,500 IU).

So there you have it y'all. Everything you always wanted to know about Vitamin A. Hey it's probably more than you want to know. But you definitely NEED to know.

WLS is not a "quick fix" for obesity. It is not the "easy way out" so many seem to think it is. This is --everything changes for the rest of your life--surgery, not to be taken lightly.

My advice to anyone who has had WLS or is thinking about it---know what is needed to maintain proper health now that we are no longer NORMAL. Eat good sound whole foods---not food products. Take your supplements religiously. Have your doc do routine blood work that includes checking your Vitamin A levels.

Hey, it is NOT standard procedure to have this test done. So don't even think you are "peachy keen" if your doc states your "labs" look great. Ask for a print out of them. Know exactly what tests they have done. Don't just blindly accept or assume this was one value they checked.

Every health consumer---not just those having WLS--- should be proactive in their own care.

Stay tuned for many more posts dealing with supplements after WLS.


Meagan said...

This is very scary!! Six years after an RNY gastric bypass, I've already dealt with anemia and b-12 deficiencies that had to be corrected with intravenous vitamins weekly for three months. My eyesight has been getting worse lately but I never thought about an A deficiency. :( I am definitely going to try to beef up my intake of A-rich foods in addition to continuing with my supplements.

BamaGal said...

I'm only 3 years out and I've already had 2 rounds IV iron---but that was last year---now I eat liver every week and take my supplements
I'm glad you got something out of this--check back I'm gonna be doing several more posts dealing with nutrition after WLS---things we aren't always told post op

Sandi said...

yep, this is great stuff, and very similar to the info my surgeon made me read before wls. He is very ahead of the game in the supplements department. I may switch to cod liver oil for awhile--I doubt my chewable multi and flax seed and the flax oil I take are keeping up with my demand for ADEK...

As usual, thanks for the very well documented head's up!

hugs my goddess!

Anonymous said...

Excellent, excellent article!

David said...

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