Some women experience real food cravings before having their period. For what ? This is the subject of a recent study, carried out by German researchers, which has just been published. She is studying the insulin trail to understand the phenomenon.
It’s a phenomenon you may be familiar with: before the start of each menstrual cycle, your hunger increases tenfold. How to explain this phenomenon ? According to a German study, this could be linked to a well-known hormone in our body, insulin.
Insulin, the hormone that regulates blood sugar levels
Insulin is a hormone made by the pancreas and plays an essential role in regulating blood sugar levels. But not only. The hormone would also have an impact on eating behavior, as well as on metabolism and fat storage.
As most studies of insulin’s action on the brain have focused on men, metabolic changes during the menstrual cycle in women remain poorly understood.
Based on this observation, scientists from Tübingen and Düsseldorf, Central Europe, wanted to study the effects of insulin in women, from a cerebral point of view.
Intranasal doses of insulin injected into participants
To do this, they brought together a cohort of 11 participants, who were subjected to hyperinsulinaemic-euglycaemic clamps, a gold standard technique for determining insulin sensitivity.
Using this procedure, insulin sensitivity was assessed in 11 women during the follicular phase (the first phase of the menstrual cycle which takes place over 10 to 18 days on average, from the first day of menstruation, until ovulation) and during the luteal phase (the second phase, which takes place after ovulation until menstruation). Brain insulin was introduced using a nasal spray and compared to placebo spray with change in glucose infusion rate as the primary endpoint.
Result: during the follicular phase, more glucose had to be infused after the administration of nasal insulin than after the administration of a placebo. Whereas during the luteal phase, no significant influence of brain insulin action on glucose infusion rate is detected after adjustment of blood glucose and insulin (secondary endpoint).
In another 15 women, hypothalamic insulin sensitivity was assessed by functional magnetic resonance imaging (fMRI) with intranasal insulin administration. Again, the responsiveness of the hypothalamus is influenced by insulin during the follicular phase but not during the luteal phase.
“NWe show that during the follicular phase, more glucose must be infused after nasal insulin administration than after placebo administration. Hypothalamus sensitivity is also influenced by insulin in the follicular phase but not in the luteal phase” write the authors.
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A link with the body’s preparation for a potential pregnancy?
In fact, participants’ brains were more sensitive to insulin during the first day of ovulation, but not in the following days.
According to scientists, this reaction, which allows energy to be stored, is linked to the preparation for a possible pregnancy.
“It is indeed tempting to speculate on the potential physiological functions of regulating brain insulin sensitivity throughout the menstrual cycle. One of the major functions of the menstrual cycle is the preparation of the uterus and the rest of the body to a possible future pregnancy. In the luteal phase, the absence of cerebral modulation of peripheral insulin sensitivity could promote energy storage in adipose tissue. explains Dr. Gérald Kierzek, emergency physician and medical director of TipsForWomens.
These natural changes in the brain’s modulation of adipose energy storage throughout the menstrual cycle could also contribute to differences in body fat distribution between the sexes and the feeling of cravings before menstruation!