Too much vitamin A can increase the risk of bone fracture

Consuming too much vitamin A can decrease the thickness of the bone, leading to bone fragility and fracture, according to a study published in the Journal of Endocrinology. The study, conducted in mice, revealed that a sustained intake of vitamin A, at levels equivalent to 4.5-13 times the daily intake recommended by humans, resulted in a significant weakening of the bones and suggested that people be cautious when they consume too much vitamin A in their diet.

Vitamin A is an essential vitamin that is important for many biological processes, including growth, vision, immunity and organ function. Our body is unable to produce vitamin A, but a healthy diet including meat, dairy and vegetables should be enough to meet the nutritional needs of the body. Some evidence suggests that people taking vitamin A supplements may increase their risk of bone damage. Previous studies on mice have shown that a short-term overdose of vitamin A, equivalent to 13 to 142 times the recommended daily intake in humans, resulted in a decrease in thickness of bone and an increased risk of fractures after only 1-2 weeks. This study is the first to examine the effects of lower doses of vitamin A, more equivalent to those consumed by people taking supplements, over longer periods.

In this study, Dr. Ulf Lerner and colleagues at the Sahlgrenska Academy of the University of Gothenburg reported that mice receiving lower doses of vitamin A, equivalent to 4.5-13 times the RDA in humans , over a longer period, also showed thinning of their bones after only 8 days, which progressed during the ten-week study period.

Dr. Ulf Lerner commented: "Previous studies on rodents have shown that vitamin A reduces bone thickness, but these studies have been conducted with very high doses of vitamin A over a short period of time. our study, we have shown that much lower concentrations of Vitamin A, a more relevant range for humans, further decreases the thickness and strength of the rodent bone. "

Dr. Ulf Lerner then intends to investigate whether doses of vitamin A adapted to human activity affect exercise-induced bone growth, an issue that has not been addressed in this study. In addition, his team will study the effects of vitamin A supplementation in elderly mice, where skeletal growth has stopped, as in the elderly.

Dr. Ulf Lerner warned, "Overconsumption of vitamin A may be a growing problem as more and more people take vitamin supplements.A vitamin D overdose may increase the risk of bone-weakening disorders in children. However, more studies are needed to study it, and in the majority of cases a balanced diet is enough to maintain the body's vitamin A requirements. "

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More information:
The study "Clinically relevant doses of cortical bone loss in vitamin A in mice" will be published in Journal of Endocrinology on Tuesday, October 09, 2018.