Vitamin A and ATP levels

[Guest guest]

Scientists Identify Vitamin A Role in Energy Production

March 2010

Vitamin A may play a critical role in the production of energy in our cells,

says an international team of researchers who claim to have solved the question

of why vitamin A deficiency causes so many diseases.

According to findings published in the FASEB Journal, vitamin A (retinol) may

play a role in the synthesis of ATP in mitochondria—the power plant of the

cells—and when vitamin A is deficient the production of energy is reduced by

30%.

Researchers led by Ulrich Hammerling from the Institute for Cancer Research, New

York, found that when vitamin A supplies are adequate, the preferred energy

sources are glycolysis and pyruvate production. On the other hand, when the

vitamin is scarce the body turns to fat reserves, preparing the organism to win

energy from fat oxidation.

However, when cells are deprived of retinol, the synthesis of ATP decreases as

does respiration. But such declines were reversed when retinol levels were

restored, and no conversion to other retinoids was observed, showing the effect

was related purely to retinol.

" Bioenergetics is fundamental to all cells, " wrote the researchers. " In view of

this tenet, it is puzzling why metabolic regulation by the pathway described in

this report depends on retinol that vertebrates cannot synthesize de novo

(anew).

" In limiting vitamin A to nutritional sources, there must be an evolutionary

advantage of such import as to override the physiological needs for vitamin A in

vision and retinoic acid-dependent transcription.

" The answer may lie in the scenario that finite amounts of vitamin A are subject

to depletion during periods of severe starvation when an organism is forced to

conserve energy. Our observation that in the absence of vitamin A energy

generation by respiration adapts downwards appears relevant in this context, "

added the researchers.

Data from vitamin A-deficient mice has previously indicated that triglycerides

accumulate in the liver and may signify a switch to fat for energy generation,

said the researchers, in order to offset the limited use of glycolysis and

pyruvate production.

" It is also predictable that chronic deviations of vitamin A transport will lead

to metabolic disease, " Hammerling and his co-workers added.

FASEB Journal 24(2):627-626, 2010