Eating fatty fish such as salmon, sardines and mackerel at least once per week may delay puberty in girls, a new study has found.
The first menstrual period of these girls is said to be significantly more delayed than those who eat such fish once per month.
Red meat, however, causes the exact opposite, as girls who consume it frequently experience their first menstrual cycle five months earlier than those who do not.
Diet seems to have a role in the age of menarche or first ever menstrual period. To investigate, researchers from the University of Michigan, Ann Arbor studied the association of the age of menarche and the consumption of red meat during ages 5 to 12 years old.
Looking At Diet And Menarche
The authors looked into the usual diets of 456 girls aged 8.4 ± 1.7 years old in Bogotá, Colombia via a food-frequency questionnaire. They followed up the participants for a median of 5.6 years.
From time to time, the researchers would ask the girls about the occurrence and the date of menarche. The findings show that the median age of menarche was 12.4 years old.
Girls who eat red meat twice per day had a notably earlier age of menarche than those who consume red meat less than four times per week.
The authors also incidentally found that those who eat fish products such as tuna or sardines more than once per week had a significantly later age of menarche than those who eat the same fish types at a frequency of less than once per month.
The authors did not find any relationship between the age of menarche and other animal food groups.
Senior author Eduardo Villamor says the team does not know what is it exactly in red meat that causes early menarche. Such components may be protein or other micronutrients that red meat naturally contain. However, it can also be byproducts resulting in meat manufacturing, processing or cooking. Another possibility is that it can come from the food being provided to the cattle.
Disease Implications
Although five months may seem like a short period of time to cause significant impacts, it is vital when it comes to population studies like this.
"It is an important difference because it is associated with the risk of disease later in life," says first author Erica Jansen. She adds that the findings are important because very few diet-associated factors are recognized to have an impact on the age of menarche.
The results of the study may also add to the knowledge about why consumption of red meat early in life is connected to elevated risk of breast cancer later in life.
Aside from breast cancer, early puberty has also been linked with obesity, heart disease and type 2 diabetes.
Villamor says that early puberty usually leads to other public health problems such as early engagement to sexual activity, teenage pregnancy, alcohol consumption and tobacco use.
Ultimately, Villamor says the team cannot give a definitive conclusion that points out to the causal role of red meat in the initiation of puberty. Despite this, he said that there is a growing number of evidence that suggests that high consumption of red meat at particular stages of life may be related to a variety of adverse health effects, especially some kinds of cancer.
The study was published in The Journal of Nutrition on Wednesday.
