Vitamin D Hormonal Deficiency

Paul L. Reller L.Ac. / Last Updated: August 03, 2017

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The Metabolic Cycle of the Vitamin D Hormones

It is now widely acknowledged that the whole metabolic cycle of the D3 hormone calcitriol, as well as the whole hormonal feedback cycle centered on this hormone we call still mistakenly refer to as Vitamin D, is all important in considerations of the so-called Vitamin D deficiency. Since the association between hormone D3 and the many serious chronic disease states linked to Vitamin D deficiency is still unclear, physicians, scientists, and patients are beginning to understand that simply supplementing with even a relatively high dose of cholecalciferol is not by itself guaranteed to correct the related health problem. The metabolic issues involved in this pathological relation between disease and Vitamin D deficiency may involve low daily production of D3, poor absorption of dietary prescursors, poor transport of either the hormonal precursors cholesterol, cholecalciferol, or calcidiol, poor conversion of one of these chemicals to the other, or to the D3 hormone calcitriol, lowered expression of D3 receptors, poor function of D3 receptors on specific target cells and tissues, and hormonal imbalances related to the regulation of D3. In addition, extrinsic factors may alter the utilization of D3, such as chronic inflammatory disease, thyroid dysfunction, adverse effects of certain medications, cortisol imbalance, and perhaps even obesity. Thus the determination of not only the optimum daily level of D3 and calcidiol in circulation, but also the individual need for the D3 hormone, is still not clearly determined by simple blood levels on lab tests and a normal range. This does not mean that supplementation does not work, but rather that it should be used within a more holistic protocol in individualized treatment that addresses these many factors affecting the hormone Vitamin D metabolism and utilization. This means that consultation and treatment with a knowledgeable Complementary Medicine physician, who spends the time and energy to help determine what is needed, and a proactive participation of the patient, is needed to really correct this problem. Of course, this requires some work on the part of the patient to actually gain a real understanding of the hormone Vitamin D metabolism.

The prohormone Vitamin D3 is cholecalciferol, which is now what we supplement with when a deficiency of circulation Vitamin D hormone is noted on blood tests. The correct amount of this hormone Vitamin D in the body is highly regulated, though, and a daily production of 20,000 to 50,000 IU (international units) is necessary to maintain our health. Vitamin D precursors in the diet supply a very small percentage of this hormone, and an array of organ systems is involved in production and regulation of the hormone we call Vitamin D. In the body cholecalciferol is made in the skin epidermis and dermis from 7-dehydrocholesterol (7DHC). This form of cholesterol may accumulate in the skin and other membranes and be linked to cholesterol depletion (re: Smith-Lemli-Opitz syndrome). Researchers have identified industrial chemicals that may cause a similar effect to the disease state, such as cyclohexanes, which are used as nonpolar solvents. A variety of exogenous chemicals are being investigated to explain problems with the Vitamin D3 metabolism, but this complex question is still poorly understood. 7HDC is equally stored in the dermis and epidermis, but the epidermal 7HDC produces 80% of the cholecalciferol. Cholecalciferol then circulates to the liver, where hydoxylation and phosphorylation occur to produce the prehormone calcidiol, which is the most prevalent form of D3 in circulation. Again, hydroxylation occurs in the kidney to produce the hormone, but this rate of hormone creation is regulated by the amount of parathyroid hormone in circulation in order to keep calcium absorption, storage and utilization tightly controlled. The D3 hormone and parathyroid hormone also regulate the amount of phosphorus in the body, which must be balanced with calcium.

Not only the kidney/adrenal glands, but other tissues in the body have the ability to make and regulate their own D3 hormone, calcitriol. Locally produced calcitriol is found in skin keratinocytes, immune cell macrophages, brain and parathyroid tissues, as well as the kidney and adrenals, and plays many important roles in the body, including cell-differentiation and control of cancerous growth. Calcitriol production is dependent on the level of circulating or stored calcidiol. Calcidiol deficiency not only creates a potential deficiency of the hormone calcitriol, but has also been found to be a risk factor for hyperparathyroidism, and is associated with a wide variety of disorders, which have already been mentioned in this article. Hyperparathyroidism is a growing concern that could account for many calcium imbalances, and is associated with subclinical hypothyroid disorders. The hyperparathyroid syndromes create excess parathyroid hormone, which decreases the rate of calcitriol production, and are often seen together with syndrome of subclinical hypothyroidism. In correction of the problem of the calcitriol production, it is logical to assume that problems with thyroid and parathyroid balance should also be addressed.

Calcium is perhaps the most highly regulated molecule in the body, and is literally found in all cells and tissues. Regulation of calcium is a complex process, but 3 major hormones lie at the heart of this complex process, the hormone Vitamin D, parathyroid hormone and calcitonin (a thyroid hormone), which interact to control absorption, utilization, transport and storage of the charged ionic calcium molecules. Thus, imbalances between these 3 important hormones will lead to serious long-term health problems. For example, higher levels of parathyroid hormone or deficient phosphorus concentrations in blood (hypophosphatemia) will increase the formation of the active D3, or calcitriol, while lower parathyroid hormone levels and excess phosphorus in blood will cause a relative D3 deficiency. The hormones prolactin, estradiol, placental lactogen and possibly somatotropin also affect the conversion and secretion of D3. These hormones appear to interact to achieve this regulation, and so just the level of one of these hormones is not very important, but rather the whole hormonal balance. Calcium demands in the body will alter the level of all of these hormones to maintain homeostasis, in a quantum effect, though. So we see that simple measurement of just Vitamin D3 calcidiol in circulation is not enough to fully evaluate D3 deficiency in relation to disease or disease prevention. Numerous human clinical studies have demonstrated that specific acupuncture stimulations modulate serum cortisol and prolactin in fertility studies (PMID: 19118825), and circulating gonadotropins and metabolic hormones in studies of PCOS (PMID: 25963796), while bioidentical estriol and progesterone stimulating topical creams effectively restore steroid hormone levels. Treatment protocol combining such protocols clearly can restore the healthy hormonal homeostasis that is needed to correct the hormone Vitamin D metabolism.

These hormonal feedback systems are very important in evaluating and treating hormonal disoders. For example, prolactin, a hormone created by the hypothalamus/pituitary complex in the brain, may increase the production of calcitriol, and increased calcitriol may stimulate increased prolactin. Prolactin, once thought to be primarily secreted to stimulate production of breast milk, is now known to have over 300 effects in the body. Prolactin, with dopamine, is involved with emotional feeling of sexual gratification, and highly elevated levels decrease the production of estrogens and testosterone temporarily, while normal levels stimulate gonadotropin and suppress gonadotropin releasing hormone. Prolactin is also involved with cell proliferation in the central and peripheral nervous systems, stimulating increased myelin production capability. Prolactin has both a diurnal and ovulatory cycle, and a seasonal cycle, and is increased during periods of high estrogen levels, especially during pregnancy. High prolactin levels inhibit FSH and LH, decreasing fertility and ovulation, and high prolactin secretion is associated with microtumors of the hypothalamus and pituitary, which could lead to subclinical hyperthyroidism or subclinical hypothyroidism. Prolactin levels may vary due to many factors, and a too simple equation of imbalance will not tell us enough to correct a specific health problem. Not only the level of active Vitamin D hormone, but the levels of calcitonin from the thyroid and parathyroid hormone from the parathyroid glands may determine a different optimum amount of prolactin in the body to properly regulate calcium metabolism. The controls of this hormonal, or endocrine, system are feedback controls, and ultimately, hormonal balance and endocrine health is needed to restore homeostasis.

While this complex physiology of Vitamin D metabolism may seem daunting to the patient, who understandably just wants to know whether to take Vitamin D supplements, and at what dose, the standard practice of providing a simplistic explanation and treatment strategy is not only not helpful, but it is in fact a lie, and malpractice. Perpetuating this standard of misleading information about hormone Vitamin D and disease should end now. Lowered hormone Vitamin D status is prevalent and a serious contributor to many diseases. To truly restore this hormone Vitamin D metabolism, though, a more thorough and holistic health protocol is needed. CIM/TCM offers an array of treatment protocols that provide an array of symbiotic effects, able to achieve a more individualized and holistic restoration of what we still euphemistically and unfortunately just call Vitamin D deficiency. While we obviously cannot just correct this hormonal metabolism with a simple stimulation from a few acupuncture points or with just a few simple herbs for a short period of time, and no human clinical trials will provide evidence of this direct simplified approach, abundant evidence of an array of health benefits that are needed along with quality cholecalciferol Vitamin D3 supplement and improved diet to restore the hormonal Vitamin D metabolism is available.

The other forms of the Vitamin D hormone family and what they do:

While the so-called Vitamin D3, ergo cholecalciferol, calcidiol and calcitriol (and its analogue), are much discussed now, the other members of this hormonal family may also play important roles in our health. D1 is the name given to the compound ergocalciferol plus lumisterol in equal proportion. Lumisterol is a carbon hydrogen oxygen compound that is produced when excess sunlight stimulates the stored 7HDC in the skin, and is an inactive compound that limits the amount of cholecalciferol that is produced. Vitamin D2 is the supplement that has long been added to our foods, and plays a specific role in the Vitamin D metabolism, but is not a substitute for D3, or the precursor cholecalciferol. Distinguishing these molecules, rather than insisting on a dumbed-down explanation, is important in medical treatment.

D2 is the name given to either ergocalciferol or calciferol, and is produced in plants and invertebrates when exposed to sunlight. D2 supplementation has long been common, in pills and in additives to foods such as milk. D2 can also produce the prehormone calcidiol, or 25-hydroxycholecalciferol, but is much less efficient than D3. Vitamin D2 added to milk is usually in the dosage of 100 IU per glass, which is not significant. Ergocalciferol has been used for decades in the United States by physicians to treat various disorders, including parathyroid imbalances.

D4 is the name given to 22,23-dihydroergocalciferol. Presently, a topical cream with D4 is being investigated for treatment of psoriasis.

D5 is the name given to sitocalciferol (made from 7-dehydrositosterol). Sitosterol is a plant sterol, or phytohormone, with a chemical structure similar to cholesterol, and found in saw palmetto, Pygeum africanum, pumpkin seed oil, soybeans, and other herbs now widely used to treat or prevent prostate hypertrophy, or enlarged prostate. Beta-sitosterol is not only touted to treat benign prostate hypertrophy (BPH), but has also been found to reduce excess cholesterol levels in circulation, and some small studies have demonstrated benefit in treating male hair loss, or balding. Analogues of 7-Dehydrositosterol (Vitamin D5 precursor) have been investigated and proposed as pharmaceutical anti-tumor, or anti-cancer treatments.