High exposure to carrageenan in young mice may impair behavior, immunity, redox and inflammatory states throughout the aging process

The rate of aging can be determined, among other factors, by the diet during childhood and adolescence. Many additives are currently added to food, including carrageenan (E-407), a thickener derived from red algae. Although the acceptable daily intake for carrageenan is periodically re-evaluated, children show the highest levels of exposure with unknown potential effects on the aging process and longevity. Therefore, the aim of the present study is to know the effects in young mice of carrageenan intake, at the maximum level exposure scenario surveyed in children, on the homeostatic (nervous and immune) systems, the redox-inflammatory state and the repercussion that this may have on the aging and longevity of the animals. Swiss mice of 2 months of age (equivalent to 8 years old children) were used and 4 experimental groups were created (N = 10 animals/group): females and males that ingested carrageenan (540 mg/kg of κ-carrageenan in 200 μL of drinking water by pipette tip administration) and control females and males that took 200 μL of water, daily for 15 days. After that time, a battery of behavioral tests was performed, and peritoneal leukocytes were extracted to assess different immune functions and their redox and inflammatory state. These tests were repeated when the mice reached adulthood (7 months) and old age (18 months). Fecal microbiota was analyzed at the same sampling times. The results showed that animals that ingested carrageenan presented elevated levels of anxiety, impaired immune function and increased oxidative-inflammatory stress, with these effects extending into adulthood and old age and leading to reduced longevity in these mice. Overall, observed microbiota changes were related more to the aging process than the carrageenan intake. In conclusion, the exposure to high doses of the food additive carrageenan in childhood may contribute to an impairment of homeostasis, and consequently of health, with an increased oxidative-inflammatory stress, which implies an accelerated aging process, leading to a lower longevity.