Vitamin normal range

Although it is being found that vitamin D metaboUtes play a role ia many different biological functions, metaboHsm primarily occurs to maintain the calcium homeostasis of the body. When calcium semm levels fall below the normal range, 1 a,25-dihydroxy-vitainin is made when calcium levels are at or above this level, 24,25-dihydroxycholecalciferol is made, and 1 a-hydroxylase activity is discontiaued. The calcium homeostasis mechanism iavolves a hypocalcemic stimulus, which iaduces the secretion of parathyroid hormone. This causes phosphate diuresis ia the kidney, which stimulates the 1 a-hydroxylase activity and causes the hydroxylation of 25-hydroxy-vitamin D to 1 a,25-dihydroxycholecalciferol. Parathyroid hormone and 1,25-dihydroxycholecalciferol act at the bone site cooperatively to stimulate calcium mobilization from the bone (see Hormones). Calcium blood levels are also iafluenced by the effects of the metaboUte on intestinal absorption and renal resorption. 

The so-called normal range of blood and serum vitamin levels is always derived from observations on healthy young subjects. How about a comparison with healthy old subjects, whose percentage in the population is steadily increasing Much may be learned about the cause of the decrease of physiological function and of the increased susceptibility to organic disease in old age, if the role of vitamins as parameter of these alterations were investigated with a view to preventive theory. 

See also individuality, biochemical as an enemy, 204-206 blood differences, 3-4 deviates, 6-7 normal ranges and, 2-4 quantitative research and, 204, 205 research into, 7 vertebral anatomy, 45 vision, 202-203 vitamin A, 162-166, 169, 199 animal studies, 163-164 growth rate relationship to intake of, 166f human needs award contest, 162-163... 

In mild forms of malabsorption, vitamin D (25,000-50,000 units three times per week) should suffice to raise serum levels of 25(OH)D into the normal range. Many patients with severe disease do not respond to vitamin D. Clinical experience with the other metabolites is limited, but both calcitriol and calcifediol have been used successfully in doses similar to those recommended for treatment of renal osteodystrophy. Theoretically, calcifediol should be the drug of choice under these conditions, because no impairment of the renal metabolism of 25(OH)D to l,25(OH)2D and 24,25(OH)2D exists in these patients. Both calcitriol and 24,25(OH)2D may be of importance in reversing the bone disease. However, calcifediol is no longer available. 

Harrison (H5) has reported that serum citrate is increased above the normal range in hypervitaminosis D. Winberg and Zetterstrom (Wl) found it to be low in an 11-month-old infant suffering from vitamin D intoxication. Forfar et al. (F7) have reported that during the active phase of idiopathic hypercalcemia, serum citrate levels are low. 

Iron deficiency may be present in postgastrectomy patients and occasionally this may mask an underlying megaloblastic anemia. Treatment of the iron deficiency will unmask the megaloblastic process and macrocytes will appear in the peripheral blood. Iron therapy appears able to influence the serum vitamin B12 level and Williams (W6) noted a substantial increase in the serum vitamin level following treatment with oral iron for 3 months. Of his patients, 36 had a low serum vitamin level before iron therapy, and in 26 the level rose to within the normal range. 

Blood tests were performed and had the following results hematocrit 33% (normal is 38%-45%) reticulocyte count 2.0% (normal is 0.5%-1.5%) mean corpuscular volume 90 (normal). A decreased erythrocyte sedimentation rate and a prothombrin time (PT) of 15 s (normal 11-13 s) were noted. A complete blood cell count values for total protein and albumin, ALT, and AST, fasting glucose, Hb-Alc, as well as amylase and lipase were within normal range. Plasma levels of vitamins A and K were below normal, and there was near absence of vitamin E. Dysmorphic red blood cells (RBC) with multiple thorny projections (acanthocytes) were present on a blood smear. All other laboratory tests and findings were within normal limits. 

On the day of admission, the patient had developed a deep venous thrombosis in his right calf, a site not involved in the injury. In investigating the underlying cause of the deep venous thrombosis, serum homocysteine was measured and found to be 17.4 pmol/L (normal is < 14 pmol/I.).To distinguish between folic acid and vitamin B12 deficiencies, a serum methylmalonic acid (MMA) assay was performed it yielded a result of 0.59 pmol/I. MMA (normal is < 0.30 pmol/L). This confirmed the presence of vitamin B12 deficiency, despite a serum B12 concentration that was within the normal range. 

The dietary history and laboratory findings for this patient pointed to calcium-deficiency as the cause of her rickets a low serum calcium within the normal range secondary hyperparathyroidism with an elevated serum concentration of PTH and a normal serum concentration of 25-hydroxyvitamin with an elevated serum concentration of 1,25-dihydroxyvitamin D, the active hormone form of vitamin D. The patient s calcium-deficiency was due to the fact that she did not have access to milk because of the expense and the lack of adequate storage facilities for fresh dairy products in the home. 

Intoxication with vitamin D causes weakness, nausea, loss of appetite, headache, abdominal pains, cramps, and diarrhea. More seriously, it also causes hypercalcemia, with plasma concentrations of calcium between 2.75 to 4.5 mmol per L, compared with the normal range of 2.2 to 2.5 mmol per L. At plasma concentrations of calcium above 3.75 mmol per L, vascular smooth muscle may contract abnormally, leading to hypertension and hypertensive encephalopathy. Hypercalciuria may also result in the precipitation of calcium phosphate in the renal tubules and hence the development of urinary calculi. Hypercalcemia can also result in calcinosis - the calcification of soft tissues, including kidneys, heart, lungs, and blood vessels. This is assumed to be the result of increased calcium uptake into tissues in response to excessive plasma concentrations of the vitamin and its metabolites. 

I.6. Various Diseases. Abbassy et al. (Al) observed in 12 cases of malnutrition (including kwashiorkor), toxic dyspepsia, 8 cases of acute nephritis, 8 cases of infective hepatitis, and muscular dystrophy an increased spontaneous excretion of xanthurenic acid, the amount of which was found to depend on the severity of the case. In all these cases, with the exception of acute nephritis and hepatitis, the amount of xanthurenic acid was restored to normal levels after vitamin Be therapy. In 8 children with mental retardation, cerebral palsy, recurrent convulsions, 5 with nephrotic syndrome, and 5 with pellagra the amount of xanthurenic acid spontaneously excreted was found to be within the normal range, indicating that pyridoxine is probably not concerned in these cases. 

Did the vitamin Bj InjectiDns succeed in bringing the serum Bn values into the normal range (Tigune 9,22) ... 

The assay for serum Bn levels is a direct lest, as it measures the concentration of the vitamin itself. The assay of MM A levels is a functional test of B12 status, as it measures a compound whose metabolism is dependent on the correct functioning of vitamin Bn- The results of the MMA test reflect the activity of methylmalonyl-CoA mutase in the liver It is thought that the functional test is more valuable than the direct test. Serum vitamin Bij levels may not reflect the functioning of the B j-requiring enzymes of the cell. Serum Bii levels may sometimes be withm the normal range despite an increased excretion of MMA. Normal scrum Bt2 values range from 0.2 to 1,0 ng/ml. Normal serum MMA levels range from 20 to 75 ng/ml, and normal urinary MMA levels from 0,6 to 3-0 pg/ml. 

The normal range of plasma concentrations of vitamins Dj and is 1 to 2 ng/ml, 25-HydK3xy itamin P3 is the form of the vitamin present at highest concentrations, with normal values ranging from 8 to 40 ng/mJ, A value of 12 ng/ml has been used as a cutoff point to indicate itamin D deficiency, though some clinicians have used lower levels to indicate vitamin D deficiency. The hormonally active form of the vitamin, l,25-(OH)jD occurs at much lower levels (15-45 pg/ml). 

Normal serum values for vitamin E range from 3.0 to 16.0 pg/ml. The marked influence of the lipid levels in the bloodstream on plasma tocopherol makes it... 

The regulation of plasma calcium levels is detailed under Vitamin D in Chapter 9. Further details on plasma cakium levels in normal and pathological situations arc revealed in the present section. Plasma calcium levels generally do not reflect calcium. status. Plasma calcium is maintained in the normal range during periods of negative cakium balance because of the actions of and l,25-(OH)2D3. Our... 

Rickets, which is diagnosed by X-rays of leg bones, heals promptly with 4000 lU of oral vitamin D per day, with treatment for a month. In performing this treatment, the physician needs to monitor plasma 25-hydrox3witamin D to make certain that they are raised to the normal range. The bone abnormalities (visible by X-ray) disappear gradually over the course of 3-9 months. Parents are instructed to take their infants outdoors for about 20 minutes per day with their faces exposed in order to prevent deficiency. Osteomalacia is treated by eating 2500 lU/day for about three months. Measurements of 25-hydroxyvitamin D, calcium, and parathyroid hormone are also part of the treatment process. 

---