"We considered it very important to study the effects [of caffeine] on the growth of infants, as the rapid growth of infants is very consistently associated with the development of childhood obesity and even adulthood," wrote Papadopoulou an e-mail. "In other words, children and adults who grow more rapidly in infancy than peers have a higher risk of being overweight or obese."
The study looked at over 50,000 women from all over Norway who were recruited from the Norwegian mother-child cohort study between 1
Based on self-reported nutritional data, caffeine intake was characterized as low (0-49 mg / day), average (50-199 mg / day), high (200-299 mg / day), or very high (300 mg / day) or more mg / day). Possible caffeine sources were coffee, black tea, caffeinated soft drinks / energy drinks, chocolate, chocolate milk and some desserts.
"It is important for pregnant women to know that caffeine comes not only from coffee but from caffeine-containing soda. Drinks can also contribute with significant amounts of caffeine," wrote Papadopoulou , "The current recommendation for pregnant women should not exceed 200 mg of caffeine intake per day, which is approximately 2-3 cups of black coffee." This recommendation is based on all scientific evidence of adverse effects of caffeine on pregnancy outcome such as miscarriage and restriction of fetal growth. " Researchers found that women who had very high caffeine intake during pregnancy had a 66% increased risk of having a child with overgrowth in their first year of low intake of caffeine. Excess growth was defined as a weight for age greater than the 75th percentile for that age.
Women who had an average or high intake of caffeine had a 10% and 30% higher risk, respectively, of having children with over-growth in infancy than children with low caffeine consumption.
"There are many risk factors for childhood obesity that occur during pregnancy," Li added.
In addition to over-growth in infancy, the study looked at whether children who were exposed to very high levels of caffeine during pregnancy became overweight in infancy. Exposure to average, high and very high caffeine content in utero was found to be associated with a significantly higher risk of overweight at the age of 3 years and 5 years.
"Our findings indicate that high maternal caffeine intake during pregnancy was associated with over-growth in infancy and obesity in later childhood, and supports the current recommendations to limit caffeine intake during pregnancy to less than 200 mg caffeine per day Day, that's about 2-3 cups of coffee … (but) we also found associations with caffeine intake below 200 mg, "said Papadopoulou.
At the age of 8 years, however, an increased risk of obesity was found only in children exposed to a very high caffeine content. Specifically, these children weighed an average of 213 grams (7.5 ounces) more at 3 years, 320 grams (11.3 ounces) more at 5 years, and 480 grams (16.9 ounces) more at 8 years old than children who were low Caffeine content were exposed.
"Once you are about 10 years old, all the other factors are added to determine obesity, especially nutrition and exercise," Li said. "Sedentary behaviors like Games, computers and television all come into play and can overwhelm the internal mechanism of caffeine intake during pregnancy. "
But the new study is the first to examine the effects of caffeine at low concentrations of 50 milligrams per day. According to Papadopoulou, it is also one of the first to look at the growth rates in the first year of life.
"Our findings on caffeine intake and rapid growth in infancy are new," she said. "The finding that caffeine intake in the area of recommendations was linked to excessive infant growth was also somewhat surprising."
According to Li, caffeine could affect the development of the hypothalamic-pituitary axis in the brain, which is responsible for the regulation of many hormones responsible for the growth and development of childhood, leading to decreased uterine growth and growth leads to increased growth after childbirth.
"We know that caffeine affects the baby's brain function … so the hypothesis is very plausible," Li said. "We know that caffeine affects the neurotransmitters that affect the brain, and we know that everything, what happens during the fetal period, is intensified and lasts on a long-term basis. "
But not everyone agrees with the current position of the organization.
"I did not like this idea," Li said, "I think the idea should drink as little as possible (caffeine), do your best, and if you can not, you absolutely should not go over 200 milligrams. "
The new study was based on self-reported data from a racially and ethnically homogenous population – one of the main limitations of the study, according to Li.
According to Tom Sanders, professor of nutrition and dietetics at King's College London who is not It also did not control breastfeeding, which is known to affect infant growth rates.
But the results add even more to the argument that increased caffeine intake during pregnancy could have long-term adverse effects on the baby's health, Papadopoulou said.
"Our findings support the current recommendation, as caffeine inputs greater than 200 mg / day were most commonly associated with (excessive) child growth," she said. "However, our study also adds to the growing body of evidence suggesting that completely avoiding caffeine during pregnancy may be advisable."