Parathyroid Hormone (PTH)

Parathyroid hormone (PTH) is an important regulator of calcium metabolism whose chronic elevation, driven primarily by dietary calcium deficiency, is a central mediator of inflammation, soft-tissue calcification, and suppressed energy production. 2 When blood calcium falls, PTH mobilizes calcium from bone, but its excess is associated with many inflammatory and degenerative diseases, including heart failure, cardiac hypertrophy, and diabetes. 3 Peat argued that simply eating an adequate amount of calcium and magnesium can alleviate many problems related to stress and aging, and that the suppression of PTH is probably the main mechanism by which intravenous calcium relaxes blood vessels and improves heart function. 2

PTH operates within a network of adaptive stress hormones, and its actions are profoundly antimetabolic. It increases the activity of nitric oxide synthase, contributing to vascular leakiness, and causes mast cells to release promoters of inflammation, including histamine and serotonin. 3 PTH suppresses phagocytosis, stimulates the proliferation of lymphocytes and T cells, and can produce anemia by a variety of mechanisms. 2 Roddy has emphasized that PTH increases lactic acid formation by bone cells and reduces carbon dioxide, shifting cellular energy production toward inefficient glycolysis. 8 Dinkov has characterized PTH as the functional link between the stress system (HPA) and the thyroid, noting that high PTH is known to suppress the synthesis of thyroid hormone. 10

The primary dietary factor governing PTH secretion is the ratio of calcium to phosphate. A generous phosphate intake, typical of Western or even "ancestral" diets heavy in muscle meats, easily leads to increased PTH if calcium intake is insufficient. 2 Peat noted that many things increase PTH, including serotonin, estrogen, cortisol, and prolactin, while progesterone and thyroid are the main things that help to inhibit it. 11 He also observed that people with high blood calcium are often overdriving their PTH by eating too much phosphate, and that increasing dietary calcium, along with vitamin D and vitamin K, can quickly normalize blood calcium levels. 11 Even baking soda can help lower PTH, and thyroid function is the crucial factor for magnesium retention, which is more important than the dietary calcium-to-magnesium ratio itself. 6

Maintaining a low PTH level is critical for preventing degenerative processes. Peat stated that if a blood test for PTH is above 40 on the standard scale, a person is probably rapidly calcifying, and he referenced a doctor who aimed to get PTH below 11, where 20 is considered below normal. 4 Dinkov added that a PTH level in the upper 50th percentile is already a cause for worry, and a level in the upper 25th percentile warrants seriously increasing calcium intake or taking vitamin D. 9 Optimal levels of carbon dioxide, such as those achieved during adaptation to high altitude, can greatly decrease PTH, an effect similar to supplementing with calcium, vitamin D, and vitamin K. 2 Frequent, smaller meals can also reduce PTH, making milk a convenient food for this purpose. 3