What is HPU?

The abbreviation HPU stands for haemopyrrollactamuria and is named after the compound that is found in the urine of a group of patients, the haemopyrrollactam-complex. This complex chemical compound is not found anywhere else in the body and is probably a waste product of metabolism. The HPL-complex is formed by the breakdown of Copro I (coproporphyrine I) and the breakdown of vitamin B6, pyridoxinic acid. Because there is a difficulty to convert normal vitamin B6 to the activated form, it is degraded easily. Even if no vitamins are taken, the level of vitamin B6 in blood can be easily elevated. In tissue HPL is partly bound to copper, as is the active form of vitamin D3 (copper-calcitriol). HPU occurs more often in women than in men.

The clinical picture is called porphyrinuria or ‘toxic induced porphyria’ because during periods of overload, in addition to the pyrroles also other intermediate products of haem synthesis, such as coproporphyrins, are secreted in the urine as well.

A number of substances play an important role in the excretion: vitamin B6 or the ‘active’ form of vitamin B6 called pyridoxal-5-phosphate. In the blood, however, an accumulation of vitamin B6 can be found. Vitamin B6 is degraded to several compounds like pyridoxinic acid. This is one of the compounds found in the HPL-complex. This accumulation can take practitioners to the wrong track, because they draw the conclusion that there is no shortage at all. However the production of active forms of vitamin B6 show low levels. This active form is involved in a large number of processes in the body, such as the metabolism of carbohydrates and fats.

This deficiency has a dual effect. It not only disturbs biochemical processes that depend on this vitamin, but it also reduces the absorption of zinc, magnesium, manganese and chrome. HPU is therefore sometimes defined as a deficiency of pyridoxal-5-phosphate. At the same time, the low levels of magnesium reduce the phosphorylation, making the body less able to metabolise pyridoxal-5-phosphate from vitamin B6. That same step, called phosphorylation, plays a role in the reduction of production of active vitamin B1 and B2.

Hit by the shortages the body gets out of balance, which can lead to numerous health problems. Especially a failure on the hormonal axis, by forming antibodies to the thyroid, worsens the picture quickly. The first symptoms may already start immediately after birth. At older age a rich variety of symptoms arises, especially after pregnancies.

The vitamin and mineral deficiency cannot be corrected by eating foods rich in vitamin B6, zinc, and manganese, because the deficits in the body are to huge. With targeted nutritional supplements, HPU prevention is good to deal with.

Just like migraine headaches, jaundice and diabetes which are in fact no disease, we prefer not to call HPU an independent disease, but an inborn error of metabolism, with a confluence of factors leading to certain other, well defined diseases such as Hashimoto.