Serum ferritin and vitamin D evaluation in response to high altitude comparing Italians trekkers vs Nepalese porters

Abstract

Altitude hypoxia induces changes in iron homeostasis with serum ferritin (sFER) response being recently linked to erythropoiesis. The main aim of this study was to investigate sFER and Vitamin D (Vit D) response to hypobaric hypoxia, taking into account factors including nutrition and ethnic origin. As part of a "Kanchenjunga Exploration & Physiology" project, 6 Italian trekkers and 6 Nepalese porters took part in a 19-days long altitude trek in the Himalayas self-recording daily food consumption. Blood samples were collected and analyzed before and after the trek for sFER and Vit D. A webbased system calculated the dietary intake, generating reports that were used for later statistical analyses. sFER decreased after the trek (on average by 26% p = 0.013, partial η 2 = 0.479) in both groups, whereas Vit D did not change in both groups. Nepalese tended to have lower sFER, but this difference was reduced when corrected for the dietary intake. Mean Cell Volume (MCV) and Hematocrit (HCT), in respect to baseline, remained higher 10 days after the trek (respectively, 87.37-88.85 fL with p = 0.044, and 43.05-44.63% with p = 0.065) in Italian trekkers. The observed reduction of sFER levels was related to altitude per se as inflammation or anemia were medically excluded. sFER, therefore, may act as a primary factor in the examination of hypobaric hypoxia in field studies. The results of this study open a new door into the mechanisms of iron homeostasis in specific tissues related to hypoxia adaptations, taking into account dietary intake and ethnic origin.

OxInflammation at High Altitudes: A Proof of Concept from the Himalayas

“…For this reason, challenges to human homeostasis by such environmental stressors [ 2 ] provide an intriguing ecological model to reproduce physiological and pathophysiological conditions that share hypoxemia as the common denominator. In fact, altitude travel has increased massively in the last few decades, and the combination of physical activity and altitude hypoxia, as in high-altitude treks, enables medical and physiological responses to be investigated in the field [ 3 , 4 ].…”

Feeding Your Himalayan Expedition: Nutritional Signatures and Body Composition Adaptations of Trekkers and Porters

“…The specific physiological signature of altitude population for dealing with acute and chronic hypobaric hypoxia exposure have been studied often in terms of metabolic and genetic bases [ 4 , 5 ]. However, little attention has been posed to the role of nutrition, which may help to unravel some mechanisms underlying altitude adaptations [ 6 ]. Moreover, the focus has been posed to highland dwellers and to lowland trekkers and climbers.…”

Human adaptation to high altitude: a review of convergence between genomic and proteomic signatures

“…These changes were associated with the modulation of immune response [ 57 ]. Transferrin levels generally decrease upon ascent to high altitude irrespective of ethnicity, possibly due to augmented erythropoiesis [ 68 ]. ANGPTL4 is a secreted glycoprotein induced by peroxisome proliferation activators and plays a physiological role in lipid and glucose metabolism [ 86 ].…”