Vitamin D – Info For WLS Gastric Bypass Roux-en-Y (RNY) Post-ops

Vitamin D

Vitamin D is a fat-soluble vitamin that is essential for maintaining normal calcium metabolism Vitamin D₃ (cholecalciferol) is the most important of the Vitamin D group and is the only Vitamin D recommended for WLS Post-ops. It can be synthesized by humans in the skin upon exposure to ultraviolet-B (UVB) radiation from sunlight, or it can be obtained from the diet. Vitamin D₂ is less effective in humans especial Post-op WLS patients. After surgery the only way for post-ops to receive adequate amounts of vitamin D₃ is via diet and vitamin supplements which must be taken for the rest of a post-op’s life..

Function & Activation of Vitamin D

Vitamin D itself is biologically inactive, and it must be metabolized to its biologically active forms. After it is consumed in the diet from food and supplements, vitamin D enters the circulation and is transported to the liver. In the liver, vitamin D is changed into a form that the body can circulate and make use of for other processes in the body. Increased dietary intake of vitamin D increases serum of 25(OH)D, making this serum level an excellent test for concentrations of Vitamin D in the body. In the kidneys, Vitamin D goes through a second transformation, resulting in the formation the most potent form of vitamin D. Most of the physiological effects of vitamin D in the body are related to the activity of form produces as a result of the kidneys transformation of the vitamin.

Mechanisms of Action

Many of the biological effects of controlled through a receptor in the body. Upon entering the nucleus of a cell, the Vitamin D associates with the receptor and promotes its association with the retinoic acid X receptor In the presence of Vitamin D, it’s receptor and the RXR complex causes binding of small sequences of DNA known as vitamin D response elements and initiates a cascade of molecular interactions that result in changes of specific genes. More than 50 genes in tissues throughout the body are known to be regulated by Vitamin D.

Calcium Balance

Maintenance of serum calcium levels within a narrow range is crucial for Post-op WLS patients. It results in normal functioning of the nervous system, as well as for bone growth and maintenance of bone density. Vitamin D is essential for the efficient utilization of calcium by the body.  The parathyroid glands sense serum calcium levels and secrete parathyroid hormone (PTH) if calcium levels drop too low. Elevations in PTH increase the activity of the Vitamin D enzyme in the kidney, resulting in increased production of  Vitamin D type that the body can utilize  to increase serum calcium levels in the body. It also causes increased the intestinal absorption of dietary calcium in normal people. Unfortunately for Post-op WLS patients this does not occur although increased re-absorption of calcium filtered by the kidneys, and  mobilizing calcium from bone when there is insufficient dietary calcium to maintain normal serum calcium levels does. Parathyroid hormone and Vitamin D receptors are required for these last two effects which are highly unlikely to be available in the bodies of Post-op WLS patients.

Cell Differentiation

Vitamin D also prevents uncontrolled propagation and mutations of cells While cellular production is essential for growth and wound healing, uncontrolled production of cells with may lead to diseases like cancer. The active form of vitamin D, inhibits propagation and stimulates the productions of appropriate cells.

Immunity

Vitamin D is a potent immune system enabler. The vitamin D receptor is expressed by most cells of the immune system, including T cells and antigen-presenting cells. There is considerable scientific evidence that the Vitamin D’s receptor has a variety of effects on immune system function, which may improve the body’s immunity and hinder the development of autoimmunity.

Insulin Secretion

The Vitamin D receptor is excreted by insulin-secreting cells of the pancreas, and the results of animal studies suggest that it plays a role in insulin secretion under conditions of increased insulin demand. Limited data in humans suggest that not enough vitamin D levels may have an adverse effect on insulin secretion and glucose tolerance in type 2 diabetic (noninsulin-dependent diabetes mellitus.

Blood Pressure Regulation

There is a whole range of studies going on the suggest that adequate vitamin D levels may be important for decreasing the risk of high blood pressure.

Deficiency

If you end up with a Vitamin D deficiency, which you most assuredly will if you’re a WLS Post-op and not taking you supplements you will end up in a position where your body will not be able to absorb enough calcium. This will result in PTH production by the parathyroid glands which will increase calcium mobilized from the skeleton to maintain normal serum calcium levels in the blood-a condition known as secondary hyperparathyroidism. Although it has long been known that severe vitamin D deficiency has serious penalty for bone health, recent research suggests that less obvious states of vitamin D shortage are common and increase the risk of osteoporosis and other health problems.

Severe Vitamin D Deficiency

Rickets: In infants and children, severe vitamin D deficiency results in the failure of bone to mineralize. Rapidly growing bones are most severely affected by rickets. The growth plates of bones continue to enlarge, but in the absence of adequate mineralization, weight-bearing limbs (arms and legs) become bowed. In infants, rickets may result in delayed closure of the fontanels (soft spots) in the skull, and the rib cage may become deformed due to the pulling action of the diaphragm. In severe cases, low serum calcium levels may cause seizures. Although fortification of foods has led to complacency regarding vitamin D in developed countries, deficiency nutritional rickets is still being reported in cities throughout the world.

Osteomalacia (softening of the bones)

Although adult bones are no longer growing, they are in a constant state of turnover, or “regeneration.” In adults with severe vitamin D deficiency, the collagenous bone matrix is preserved but bone mineral is progressively lost, resulting in bone pain and osteomalacia (soft bones).

Muscle Weakness and Pain

Vitamin D deficiency causes muscle weakness and pain in children and adults. Muscle pain and weakness were a prominent symptoms of vitamin D deficiency. In a study of a 150 consecutive patients referred to a clinic in Minnesota for the evaluation of persistent, nonspecific musculoskeletal pain, 93% had serum 25(OH)D levels indicative of vitamin D deficincy.

Risk Factors for Vitamin D Deficiency

• Exclusively breast-fed infants:
• Dark skin:
• Aging:
• Covering all exposed skin or using sunscreen whenever outside
• Fat malabsorption syndromes
• Inflammatory bowel disease
• Obesity: Obesity increases the risk of vitamin D deficiency. Once vitamin D is synthesized in the skin or ingested, it is deposited in body fat stores, making it less available to people with large stores of body fat.
• Post-op WLS patients with a mal-absorptive component to their surgery

Assessing Vitamin D Nutritional Status

Growing awareness that vitamin D insufficiency has serious health consequences beyond rickets and osteomalacia highlights the need for accurate assessment of vitamin D nutritional status. Serum 25(OH)D level is the best indicator of vitamin D deficiency. In general, serum 25(OH)D values less than 20-25 nmol/L (8-10 ng/mL) indicate severe deficiency associated with rickets and osteomalacia. Calcium absorption levels are not optimized until serum 25(OH)D levels reach approximately 80 nmol/L (32 ng/mL). Data from supplementation studies indicate that vitamin D intakes of at least 800-1,000 IU/day are required by adults living in temperate latitudes to achieve serum 25(OH)D levels of at least 80 nmol/L .

Disease Prevention

Vitamin D is known to be beneficial for the following:

·         Osteoporosis

• Cancer
  • Colorectal Cancer
  • Breast Cancer
  • Prostate Cancer
• Autoimmune Diseases
• Hypertension (High Blood Pressure)

Sources

Sunlight

Solar ultraviolet-B radiation (UVB; wavelengths of 290 to 315 nanometers) stimulates the production of vitamin D₃ in the epidermis of the skin. Sunlight exposure can provide most people with their entire vitamin D requirement. Children and young adults who spend a short time outside two or three times a week will generally synthesize all the vitamin D they need to prevent deficiency. One study reported that serum vitamin D concentrations following exposure to 1 minimal erythemal dose of simulated sunlight (the amount required to cause a slight pinkness of the skin) was equivalent to ingesting approximately 20,000 IU of vitamin D₂. People with dark-colour skin synthesize markedly less vitamin D on exposure to sunlight than those with light-colour skin. The application of sunscreen with an SPF factor of 8 reduces production of vitamin D by 95%. In latitudes around 40 degrees north or 40 degrees south (Boston is 42 degrees north), there is insufficient UVB radiation available for vitamin D synthesis from November to early March. Ten degrees farther north or south (Edmonton, Canada) the “vitamin D winter” extends from mid-October to mid-March. According to Dr. Michael Holick, as little as 5-10 minutes of sun exposure on arms and legs or face and arms three times weekly between 11:00 am and 2:00 pm during the spring, summer, and fall at 42 degrees latitude should provide a light-skinned individual with adequate vitamin D and allow for storage of any excess for use during the winter with minimal risk of skin damage.

Food sources

Vitamin D is found naturally in very few foods. Foods containing vitamin D include some fatty fish (mackerel, salmon, sardines), fish liver oils, and eggs from hens that have been fed vitamin D. In the U.S., milk and infant formula are fortified with vitamin D so that they contain 400 IU (10 mcg) per quart. However, other dairy products, such as cheese and yogurt, are not always fortified with vitamin D. Some cereals and breads are also fortified with vitamin D. Recently, orange juice fortified with vitamin D has been made available in the U.S. and Canada. Accurate estimates of average dietary intakes of vitamin D are difficult because of the high variability of the vitamin D content of fortified foods. Vitamin D contents of some vitamin D-rich foods are listed in the table below in both international units (IU) and micrograms (mcg).

Food	Serving	Vitamin D (IU)	Vitamin D (mcg)
Pink salmon, canned	3 ounces	530	13.3
Sardines, canned	3 ounces	231	5.8
Mackerel, canned	3 ounces	213	5.3
Quaker Nutrition for Women Instant Oatmeal	1 packet	154	3.9
Cow’s milk, fortified with vitamin D	8 ounces	98	2.5
Soy milk, fortified with vitamin D	8 ounces	100	2.5
Orange juice, fortified with vitamin D	8 ounces	100	2.5
Cereal, fortified	1 serving (usually 1 cup)	40-50	1.0-1.3
Egg yolk	1 large	21	0.53

Supplements

Most vitamin D supplements available without a prescription contain cholecalciferol (vitamin D₃), which is more potent than (vitamin D₂). Multivitamin supplements generally provide 400 IU (10 mcg) of vitamin D. Single ingredient vitamin D supplements may provide 400-2,000 IU of vitamin D, but 400 IU is the most commonly available dose. A number of calcium supplements may also provide vitamin D.

None of these are appropriate for Post-op WLS patients. Recommended dosages for Post-op WLS Patients is 500-1000 micrograms in an oil based gel-cap taken in conjuction with your calcium supplement. In other words, vitamin D tablets do not work and calcium tablets with added Vitamin D do NOT work.. It is shameful. Numerous WLS pateints taking calcium tablets with D–have been seen with Vitamin D blood levels of zero.

You may have to look, but if you want to enjoy the extraordinary benefits of vitamin D replacement, it must be an oil-based capsule.

Safety

Toxicity

Vitamin D toxicity creates abnormally high calcium levels (hypercalcemia), which could result in bone loss, kidney stones, and calcification of organs like the heart and kidneys if untreated over a long period of time. Hypercalcemia has been observed following daily doses of greater than 50,000 IU of vitamin D. When the Food and Nutrition Board of the Institute of Medicine established the reasonable upper intake level for vitamin D, published studies that adequately documented the lowest intake levels of vitamin D that induced hypercalcemia were very limited. Because the consequences of hypercalcemia are severe, the Food and Nutrition Board established a very conservative UL of 2,000 IU/day (50 mcg/day) for children and adults. Research published since 1997 suggests that the UL for adults is likely overly conservative and that vitamin D toxicity is very unlikely in healthy people at intake levels lower than 10,000 IU/day. Vitamin D toxicity has not been observed to result from sun exposure. Certain medical conditions can increase the risk of hypercalcemia in response to vitamin D, including primary hyperparathyroidism, sarcoidosis, tuberculosis, and lymphoma. People with these conditions may develop hypercalcemia in response to any increase in vitamin D nutrition and should thus consult a qualified health care provider regarding any increase in vitamin D intake.

Drug interactions

The following medications increase the metabolism of vitamin D and may decrease serum 25(OH)D levels: phenytoin (Dilantin), fosphenytoin (Cerebyx), phenobarbital (Luminal), carbamazepine (Tegretol), and rifampin (Rimactane). The following medications should not be taken at the same time as vitamin D because they can decrease the intestinal absorption of vitamin D: cholestyramine (Questran), colestipol (Colestid), orlistat (Xenical), mineral oil, and the fat substitute Olestra. The oral anti-fungal medication, ketoconazole, inhibits the 25(OH)D₃-1-hydroxylase enzyme and has been found to reduce serum levels of 1,25(OH)D in healthy men. The induction of hypercalcemia by toxic levels of vitamin D may precipitate cardiac arrhythmia in patients on digitalis (Digoxin).

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