January 2019

Got Sun??? Not in Central Pennsylvania for sure. Let's go to the vitamin aisle and buy some Vitamin-D


Sources: very few foods contain natural Vitamin-D: fish liver oils, egg yolk, fortified milk, synthesized in skin exposed to UV light. Vitamin-D3 (cholecalciferol) comes from animal source. Vitamin-D2 (ergocalciferol) comes from plant sources.

Function: acts as a hormone, and plays a role in calcium homeostasis. Vitamin D regulates calcium and phosphorus metabolism. Following conversion to active metabolites (eg, calcifediol, calcitriol), maintenance of normal calcium and phosphate concentrations is achieved by promoting intestinal calcium and phosphate absorption in the gut, mobilization of calcium from bone, and reduction of renal calcium/phosphate excretion. Calcitriol is the most active metabolite.

Deficiency: More adults are deficient in vitamin D for the following reasons:
  • increased use of sunscreens
  • spending more time indoors
  • and less efficient vitamin D absorption as people age
  • Darker skin and living at higher latitudes also increase risk.
  • renal failure, hypoparathyroidism, estrogens, phenytoin, phenobarbital, fat malabsorption, high alcohol consumption
  • Consider testing for patients who are likely to be deficient such as house bound elderly, especially in a nursing home.
Rickets: still common in tropical countries even though adequate skin exposure. Soft bones in children become easily deformed. Low blood calcium & phosphate occur because of Vitamin-D deficiency. Lack of Vitamin -D stimulates parathyroid hormone to restore calcium levels.

DOSE: adults recommend 800-2000iu per day. Feel comfortable recommending up to 2000iu of Vitamin-D without doing the 25-hydroyx-vitamin-D level. Most evidence from studies suggests that to prevent falls, a dose of at least 800 IU per day is required for our elderly patients.

Do I have to swallow a capsule, what about drinking milk, or exposure to sunshine? Dairy Products: It takes about 5 quarts of milk, to equal 2000iu in a capsule…. not to mention over 2750 calories!

Sun Exposure: Sun Exposure (Ultraviolet-B) 2 to 3 times a week during mid-day. Bare arms & legs for10-15 minutes per session is usually adequate. The effect of sunlight exposure and vitamin D synthesis is reduced in individuals with darker skin pigment. Effective use of a sunscreen does block the synthesis of Vitamin-D in the dermis. Middle aged and elderly persons who use sunscreens daily have significantly lower serum concentrations of 25-Hydroxyvitamin D3. However, the benefits of using a sunscreen, far outweigh the disadvantages of a decrease in Vitamin-D. A local dermatologist told me “it is easier to treat Vitamin-D deficiency than it is to treat skin cancer...so use a sunscreen.”

What is the difference between ergocalciferol (Vit-D2) and cholecalciferol (Vit-D3): Vitamin D2 (ergocalciferol) available as Drisdol® comes from ergosterol, a plant sterol, and yeast. Vitamin D3 (cholecalciferol) is synthesized in the skin via 7-dehydrocholesterol, a cholesterol precursor. The vitamin D2 in supplements is made by irradiating ergosterol from yeast, and vitamin D3 in supplements is made by irradiating 7-dehydrocholesterol from lanolin. Both D2 and D3 are efficient at raising serum vitamin D levels. But at high doses vitamin D3 seems be almost twice as potent. In patients with renal disease (especially stage 5 or dialysis patients), production of active vitamin D (calcitriol) is impaired, and use of calcitriol (Rocaltrol) or other active vitamin D sterol may be indicated.

What about Infants & children?
  • Recommended daily intake of vitamin D is 400 IU per day in all infants (beginning in the first few days of life), children, and adolescents.
  • Breastfed and partially breastfed infants should begin vitamin D supplementation beginning in the first few days of life.
Excessive dose: Side effects with excessive use may include nausea, anorexia, weight loss, constipation, polyuria, polydipsia, hypertension, weakness, and muscle aches or stiffness.

Under the FDA’s new labeling regulations for foods and dietary supplements that take effect by January 1, 2020 (for companies with annual sales of $10 million or more) or January 1, 2021 (for smaller companies), vitamin D will be listed only in mcg and not IUs. New labeling requirements for FAT SOLUBLE vitamins are to take effect, to label fat soluble vitamins by their weight (in mcg) as opposed to measure activity (in IU)

To convert Vitamin D: From IU to mcg: IU/40 = mcg

INTERNATIONAL UNITS (old labeling) MICROGRAMS (new labeling)
400iu 10mcg
800iu 20mcg
1000iu 25mcg
2000iu 50mcg
5000iu 125mcg
50,000iu Rx only 1250mcg= 1.25mg

As we continue our review of the fat soluble vitamins, lets discuss Vitamin-D, the one fat soluble vitamin we should be recommending. In a study done in 2011, the overall prevalence rate of vitamin D deficiency was 41.6%, with the highest rate seen in blacks (82.1%), followed by Hispanics (69.2%).

With 41% of the population being vitamin D deficient, especially in these latitudes, we need to be recommending this Vitamin a whole lot more. Drinking milk and sun exposure is not the answer to correcting this wide scale deficiency. People low in vitamin D who take a supplement may be less likely to fall. That makes sense, given that vitamin D plays a key role in keeping bones and muscles strong.

Have a great day on the bench!!

Next time you are in the butcher shop... avoid the polar bear liver!

Now we start our journey through the fat-soluble vitamins of A, D, E, K. These vitamins can accumulate and cause adverse effects. Rarely does someone get excess fat-soluble vitamins from the diet, but excess supplementation may cause accumulation and potential serious side effects. Vitamin-A

What it does: Vitamin A is the name of a group of fat-soluble retinoids, which are involved in immune function, vision, reproduction, and cellular communication. Vitamin A is critical for vision as an essential component of rhodopsin, a protein that absorbs light in the retinal receptors, and because it supports the normal differentiation and functioning of the conjunctival membranes and cornea. Vitamin A also supports cell growth and differentiation, playing a critical role in the normal formation and maintenance of the heart, lungs, kidneys, and other organs
  • Dietary sources: fish liver oils, egg yolks, green leafy, orange & yellow vegetables.
  • Random useless fact: Toxic doses of Vitamin-A if polar bear liver is consumed.
Deficiency States:
  • Night blindness: early sign of Vitamin-A deficiency. May progress to xerophthalmia which is dryness & ulceration of the cornea. May progress to blindness.
  • See decrease in heath and integrity of skin
  • Patients that need Vitamin supplementation include those taking Orlistat (Alli/Xenical), cystic fibrosis patients; however, deficiency is rare in the United States.
Adverse effects: dry mucus membranes, cheilitis, yellowing of skin, fatigue, nausea, hair loss, headache, vertigo, blurred vision, birth defects, loss of muscular coordination, dry scaly skin. To help remember the side effects of Vitamin A therapy think of the topical side effects of Accutane (isotretinoin), which is a Vitamin-A analog.
  • Multivitamin supplements typically contain 2,500–10,000 IU vitamin A, often in the form of both retinol and beta-carotene
  • RDAs for vitamin A are given as mcg of retinol activity equivalents (RAE) to account for the different bioactivities of retinol and provitamin A carotenoids.
  • Excess Vitamin-A supplementation: leads to increased intracranial pressure (pseudotumor cerebri), dizziness, nausea, headaches, skin irritation, pain in joints and bones, coma, and even death.
Under the FDA’s new labeling regulations for foods and dietary supplements that take effect by January 1, 2020 (for companies with annual sales of $10 million or more) or January 1, 2021 (for smaller companies), vitamin A will be listed only in mcg RAE and not IUs. New labeling requirements for FAT SOLUBLE vitamins are to take effect, to label fat soluble vitamins by their weight (in mcg) as opposed to measure activity (in IU)
  • To convert Vitamin A as retinol: From IU to mcg: IU/3.33 = mcg
INTERNATIONAL UNITS (old labeling) MICROGRAMS (new labeling)
a5000iu 1500mcg (1.5mg)
8000iu 2400mcg (2.4mg)
10,000iu 3000mcg (3mg)
  • To convert Vitamin A as beta-carotene: From IU to mcg: IU/1.66 = mcg
INTERNATIONAL UNITS (old labeling) MICROGRAMS (new labeling)
25,000iu 15,000mcg (15mg)

Smokers should avoid Vitamin-A supplements. Taking beta-carotene seems to increase the risk of lung cancer in people who smoke (especially those smoking more than 1 pack per day), former smokers, asbestos exposure, and those who use alcohol (one or more drinks per day) in addition to smoking. Beta-carotene from the diet does not seem to have this adverse effect. (CARET and ATBC studies)

As the writer of these practice points, I always try to write things that are clinically relevant, that is applicable to a patient you might see in your pharmacy or clinic. I frequently use the example of polar bear liver as a fun fact, but of no clinical applicability. I have yet to have ever seen a case of hypervitaminosis-A due to eating polar bear liver. We have lots of grocery stores in our area, but I’ve never seen polar bear liver for sale!

Research has shown that a healthy adult person can tolerate a maximum of around 10,000 units of vitamin A. Adverse effects occur comes 25,000 and 33,000 units of ingestion. One pound of polar bear liver — a fist-sized chunk and barely a meal — can contain 9 million units of vitamin A!

Knowing to avoid Vitamin-A supplementation in smokers is far more critical to our patient’s safety, than the knowledge of the adverse effects of polar bear liver consumption!

Have a great day on the bench!!

We expect a LOT from our vitamin-C ! From prevention of colds to cancer!

Let’s wrap up all of the water-soluble vitamins this week. We are familiar the B-complex, they are short lived in the body, but remember that Vitamin-B-12 is stored in the liver and we have 2 years on board! So…. What happened to the other Vitamin-B numbers??
  • Vitamin B4: adenine: is synthesized by the human body.
  • Vitamin B8: adenosine monophosphate, is synthesized by the human body.
  • Vitamin B10: para-aminobenzoic acid (PABA)
  • Vitamin B11: pteryl-hepta-glutamic acid, one of five folates necessary for humans
So here is our last water soluble vitamin…
Vitamin-C (ascorbic acid)