Based on a new study performed in people lower hemoglobin levels may protect human-being from both obesity and metabolic syndrome. The phenomenon may be related to the body's response to low-oxygen conditions and is used, for example, by endurance athletes in high-altitude training.
Hemoglobin is a protein in your red blood cells that carries oxygen to your body's organs and tissues and transports carbon dioxide from your organs and tissues back to your lungs.
Hemoglobin levels vary from one individual to another, with normal levels ranging from 117 to 155 gr/liter in females and 134 to 167 gr/liter in males.
The hemoglobin levels are associated with body mass index, glucose metabolism, blood lipids, and blood pressure, with subjects having lower hemoglobin levels being healthier in terms of metabolic measures. The study considered hemoglobin values within the normal range.
"We found a clear association between hemoglobin levels and key cardiovascular traits, and the associations became more pronounced as the subjects aged," said the principal investigators, Professor Johan Auvinen.
The effect of lower hemoglobin observed in this research is related to lack of oxygen in the body and the corresponding response (HIF response) which is activated as a result. The research team of Professor Peppi Karppinen is internationally known for its studies on this phenomenon. The finding builds up the understanding of the central role that the HIF response has in balancing the body's energy metabolism.
"Hemoglobin levels are a good measure of the body's ability to carry oxygen. A mild lack of oxygen activates the HIF response, which makes the body's energy metabolism less economical and thus may protect against obesity and unfavorable metabolism," explains Karppinen, who guided the study.
Working at the Faculty of Biochemistry and Molecular Medicine, Karppinen's team has already shown in previous research that activation of the hypoxia response protects mice from obesity, metabolic syndrome, fatty liver, and atherosclerosis (hardening of the arteries). The study now published is the first to declare the link between oxygen deficiency and a wide range of metabolism.