Supplements, calcium, lead

Parathyroidectomy is a treatment of last resort for sHPT, but should be considered in patients with persistently elevated iPTH levels above 800 pg/mL (800 ng/L) that is refractory to medical therapy to lower serum calcium and/or phosphorus levels.39 A portion or all of the parathyroid tissue may be removed, and in some cases a portion of the parathyroid tissue may be transplanted into another site, usually the forearm. Bone turnover can be disrupted in patients undergoing parathyroidectomy whereby bone production outweighs bone resorption. The syndrome, known as hungry bone syndrome, is characterized by excessive uptake of calcium, phosphorus, and magnesium for bone production, leading to hypocalcemia, hypophosphatemia, and hypomagnesemia. Serum ionized calcium levels should be monitored frequently (every 4 to 6 hours for the first 48 to 72 hours) in patients receiving a parathyroidectomy. Calcium supplementation is usually necessary, administered IV initially, then orally (with vitamin D supplementation) once normal calcium levels are attained for several weeks to months after the procedure. 

For acute symptomatic hypocalcemia, 200 to 300 mg of elemental calcium is administered IV and repeated until symptoms are fully controlled. This is achieved by infusing 1 g of calcium chloride or 2 to 3 grams of calcium at a rate no faster than 30 to 60 mg of elemental calcium per minute. More rapid administration is associated with hypotension, bradycardia, or cardiac asystole. Total calcium concentration is commonly monitored in critically ill patients. Under normal circumstances, about half of calcium is loosely bound to serum proteins while the other half is free. Total calcium concentration measures bound and free calcium. Ionized calcium measures free calcium only. Under usual circumstances, a normal calcium level implies a normal free ionized calcium level. Ionized calcium should be obtained in patients with comorbid conditions that would lead to inconsistency between total calcium and free serum calcium (abnormal albumin, protein, or immunoglobulin concentrations). For chronic asymptomatic hypocalcemia, oral calcium supplements are given at doses of 2 to 4 g/day of elemental calcium. Many patients with calcium deficiency have concurrent vitamin D deficiency that must also be corrected in order to restore calcium homeostasis.2,37,38... 

Some calcium products contain lead.12 While the clinical significance and long-term risks are unknown, it is best to use supplements without a high lead content. Because of the number of calcium supplements available, patients may find it overwhelming to choose a supplement. Health care providers can help... 

Bourgoin BP, Evans DR, Cornett JR, et al. 1993. Lead content in 70 brands of dietary calcium supplements. Am J Pub Health 83(8) 1155-1160. 

What are things made from We have become a society obsessed with questions about composition, and for good reason. Lead in petrol shows up in the snow fields of Antarctica mercury poisons fish in South America. Radon from the earth poses health hazards in regions built on granite, and natural arsenic contaminates wells in Bangladesh. Calcium supplements combat bone-wasting... 

Disease Hypoparathyroidism Pathophysiology Decreased parathyroid hormone secretion leads to impaired bone resorption and hypocalcemia Primary Drug Treatment Calcium supplements, vitamin D... 

Diuretics. Hypercalcaemia may develop in patients administered thiazide diuretics with either calcium or vitamin D supplements, leading to a need... 

The long-term intake of hydralazine could lead to vitamin B6 deficiency, while the therapeutic effects of verapamil could be antagonized by calcium supplements. 

When calcium carbonate is used in tablets containing aspirin and related substances, traces of iron may cause discoloration. This may be overcome by inclusion of a suitable chelating agent. Grades with reduced lead levels are commercially available for use in antacids and calcium supplements. 

Calcium from clean, natural sources, such as fresh vegetables, has proven health benefits. We will talk about dairy products later in the book. Calcium supplements unadulterated by processing practices that involve chemicals or fillers (such as lead, which is found in many brands of calcium supplements) may be beneficial as well. Their effectiveness has as much to do with the body s capacity to assimilate and use the calcium as it does with the quantity of the calcium. If a product claim sounds too good to be true, chances are it is. 

Not all supplements are created equal. That multivitamin at the grocery or big-box store is not the same as the professional-grade multivitamin your natural medicine doctor recommends. The doses, and even the ingredients, may be different. You may be shocked to learn that many of your favorite supplements are acidic. They can contain preservatives, alcohol, and sugar or other sweeteners, all of which can create harmful acidity in your body. Some supplements contain binders or fillers, or even heavy metals such as lead (a common problem in many calcium supplements). In addition, the manufacturing processes used by many nutritional supplement companies cause these pills to become acidic. This can happen through contamination when the supplement is being produced. Enzyme supplements, for example, may be... 

PO/IV. Well absorbed, 80% metabolized in first pass. 90% protein bound. Metabolites are active. Half-life is 5 hrs but may be up to 20 hrs in patients with cirrhosis. Patient on IV blockers or digitalis. A-V node block, sick sinus syndrome, cardiogenic shock, heart failure, hypotension. Beta blockers or digitalis Increases likelihood of bradycardia or A-V blockade. Quinicfine or prazosin Increases hypotension. Digoxin levels are increased. Cimetidine reduces verapamil clearance. Calcium supplements may inhibit actions of verapamil. Depolarization (leading to contraction) of vascular smooth muscle is dependent on calcium entry. Vasodilation is induced by calcium entry blockers because they inhibit calcium influx. 

Diuretics. Hypercalcaemia may develop in patients administered thiazide diuretics with either calcium or vitamin D supplements, leading to a need to monitor plasma or serum calcium levels. The concurrent use of potassium-sparing diuretics, and other potassium supplements or potassium-containing salt substitutes, could lead to serious hyperkalaemia. Hyperkalaemia is known to interfere with the absorption of vitamin B12. There is a need to warn patients and monitor serum potassium levels. The risk of hypokalaemia is minimal with low doses of thiazides, for example 5 mg of bendroflumethiazide. Hypokalaemia is a concern in patients receiving treatment with drugs such as digoxin, amiodarone, disopyramide or flecainide (drugs used to treat cardiac disorders). 

Dietary calcium supplements have been found to contain lead. Natural source and bone meal supplements tend to have higher amounts of lead than dolomite supplements. Since... 

Bernard P. Bourgoin et al., Lead Content in 70 Brands of Dietary Calcium Supplements, American Journal of Public Health 83 (1993) 1155-1160. Refer to article for amount of lead in specific calcium supplements. 

Gulson, B.L., Mizon, K.J., Korsch, M.J., Palmer, J.M., Donnelly, J.B., 2004. Blood lead changes during pregnancy and postpartum with calcium supplementation. Environ. Health Perspect. 112, 1499-1507. 

Pregnancy Similarly, the effects of calcium supplement prescribed during pregnancy on the risk of preterm birth or low birth weight infants is inconclusive [69. A similar literature survey-based study concluded that calcium supplement during pregnancy may help reduce the incidence of pre-eclampsia, especially in a population at risk and in those with low baseline calcium intake. However, inadequate calcium intake may lead to an increased incidence of hypertension [70 j. 

This mineral, which is also known as dolomitic limestone, is a major ingredient in several antacids, and food supplements. It is a mixture of approximately equal parts of calcium carbonate and magnesium carbonate. Dolomitic limestone contains about 5 times as much magnesium, and about 5/8 as much calcium as ordinary limestone. A typical analysis of dolomite follows calcium, 22.30% chlorine, 0.12% iron, 0.08% magnesium, 9.99% phosphorus, 0.04% and potassium, 0.36°/o. Dolomite is sometimes used as a calcium supplement for humans however, it should be tested and found free of lead and other impurities. 

Amarasiriwardena, D., Sharma, K., and Barnes, R. M. (1998). Determination of lead concentration and lead isotope ratios in calcium supplements by inductively coupled plasma mass spectrometry after high pressure, high temperature digestion. Fresenius J. Anal. Chem. 362(5), 493. 

When heated, sodium hydrogencarbonate readily decomposes evolving carbon dioxide, a reaction which leads to its use as baking powder when the carhon dioxide evolved aerates the dough. In the soda-ammonia process the carbon dioxide evolved is used to supplement the main carbon dioxide supply obtained by heating calcium carbonate ... 

The calcium oxide product is supplemented with fresh limestone and returned to the fluidized bed. Two undesirable side reactions can occur in the regeneration of spent lime leading to the production of calcium sulfide ... 

Cathodic protection is a useful supplement to other forms of water treatment, as a general corrosion inhibiting device in HW boilers, or where specific design configurations can lead to inadequately protected localized metal in steam boilers. Where BW makeup demands are minimal and boiler output is fairly constant, cathodic protection devices can also provide some measure of protection against hardness scales. Calcium carbonate salt is formed as a floc-culant or soft sludge rather than a hard scale, due to the peptizing effects of a zinc hydroxide complex formed from zinc ions in alkaline BW. 

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